10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

____________________________________________________________________________

FORM 10-K

(Mark One)
☒	ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
FOR THE FISCAL YEAR ENDED		December 31, 2021
OR
☐	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission file number: 1-7933

___________________________________________________________________________________________

Aon plc

(Exact name of registrant as specified in its charter)

IRELAND	98-1539969
(State or other jurisdiction of	(I.R.S. Employer
incorporation or organization)	Identification No.)

Metropolitan Building, James Joyce Street, Dublin 1, Ireland              D01 K0Y8

     (Address of principal executive offices)                      (Zip Code)

+353 1 266 6000

(Registrant’s Telephone Number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Class A Ordinary Shares, $0.01 nominal value	AON	New York Stock Exchange
Guarantees of Aon plc’s 4.00% Senior Notes due 2023	AON23	New York Stock Exchange
Guarantees of Aon plc’s 3.50% Senior Notes due 2024	AON24	New York Stock Exchange
Guarantees of Aon plc’s 3.875% Senior Notes due 2025	AON25	New York Stock Exchange
Guarantees of Aon plc’s 2.875% Senior Notes due 2026	AON26	New York Stock Exchange
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.05% Senior Notes due 2031	AON31	New York Stock Exchange
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.60% Senior Notes due 2031	AON31A	New York Stock Exchange
Guarantees of Aon plc’s 4.25% Senior Notes due 2042	AON42	New York Stock Exchange
Guarantees of Aon plc’s 4.45% Senior Notes due 2043	AON43	New York Stock Exchange
Guarantees of Aon plc’s 4.60% Senior Notes due 2044	AON44	New York Stock Exchange
Guarantees of Aon plc’s 4.75% Senior Notes due 2045	AON45	New York Stock Exchange
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.90% Senior Notes due 2051	AON51	New York Stock Exchange

Securities registered pursuant to Section 12(g) of the Act: NONE

________________________________________________________________________________________________________________________________________________________________________________

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act. Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ☒ Accelerated filer ☐ Non-accelerated filer ☐ Smaller reporting company ☐ Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of June 30, 2021, the aggregate market value of the registrant’s Class A Ordinary Shares held by non-affiliates of the registrant was $53,867,751,208 based on the closing sales price as reported on the New York Stock Exchange — Composite Transaction Listing.

Number of the registrant’s Class A Ordinary Shares of Aon plc, $0.01 nominal value, outstanding as of February 17, 2022: 213,944,460.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s proxy statement for its 2022 Annual General Meeting of Shareholders are incorporated by reference in this report in response to Part III, Items 10, 11, 12, 13, and 14.

Information Concerning Forward-Looking Statements

This report contains certain statements related to future results, or states our intentions, beliefs, and expectations or predictions for the future, which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements represent management’s expectations or forecasts of future events. Forward-looking statements are typically identified by words such as “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “project,” “intend,” “plan,” “probably,” “potential,” “looking forward,” “continue,” and other similar terms, and future or conditional tense verbs like “could,” “may,” “might,” “should,” “will,” and “would.” You can also identify forward-looking statements by the fact that they do not relate strictly to historical or current facts. For example, we may use forward-looking statements when addressing topics such as: market and industry conditions, including competitive and pricing trends; changes in our business strategies and methods of generating revenue; the development and performance of our services and products; changes in the composition or level of our revenues; our cost structure and the outcome of cost-saving or restructuring initiatives; the outcome of contingencies; dividend policy; the expected impact of acquisitions, dispositions, and other significant transactions or the termination thereof; pension obligations; cash flow and liquidity; expected effective tax rate; potential changes in laws or future actions by regulators; and the impact of changes in accounting rules. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from either historical or anticipated results depending on a variety of factors. Potential factors, which may be revised or supplemented in subsequent reports filed or furnished with the Securities and Exchange Commission (the “SEC”), that could impact results include:

•changes in the competitive environment or damage to our reputation;

•fluctuations in currency exchange and interest rates that could impact our financial condition or results;

•changes in global equity and fixed income markets that could affect the return on invested assets;

•changes in the funded status of our various defined benefit pension plans and the impact of any increased pension funding resulting from those changes;

•the level of our debt and the terms thereof reducing our flexibility or increasing borrowing costs;

•rating agency actions that could limit our access to capital and our competitive position;

•our global tax rate being subject to a variety of different factors, which could create volatility in that tax rate;

•changes in our accounting estimates and assumptions on our financial statements;

•limits on our subsidiaries’ ability to pay dividends or otherwise make payments to us;

•the impact of legal proceedings and other contingencies, including those arising from acquisition or disposition transactions, errors and omissions and other claims against us;

•the impact of, and potential challenges in complying with, laws and regulations of the jurisdictions in which we operate, particularly given the global nature of operations and the possibility of differing or conflicting laws and regulations, or the application or interpretation thereof, across such jurisdictions;

•the impact of any regulatory investigations brought in Ireland, the United Kingdom (the “U.K.”), the United States (the “U.S.”). and other countries;

•failure to protect intellectual property rights or allegations that we have infringed on the intellectual property rights of others;

•general economic and political conditions in the countries in which we do business around the world, including the withdrawal of the U.K. from the European Union (the “E.U.”);

•the failure to retain, attract and develop experienced and qualified personnel;

•international risks associated with our global operations;

•the effects of natural or man-made disasters, including the effects of the COVID-19 and other health pandemics and the impacts of climate change;

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•the potential for a system or network disruption or breach to result in operational interruption or improper disclosure of confidential, personal, or proprietary data, and resulting damage to our reputation;

•our ability to develop and implement new technology;

•the actions taken by third parties that perform aspects of our business operations and client services;

•the extent to which we are exposed to certain risks, including lawsuits, related to our actions we may take in being responsible for making decisions on behalf of clients in our investment consulting business or in other advisory services that we currently provide, or will provide in the future;

•our ability to continue, and the costs and risks associated with, growing, developing and integrating acquired business, and entering into new lines of business or products;

•our ability to secure regulatory approval and complete transactions, and the costs and risks associated with the failure to consummate proposed transactions;

•changes in commercial property and casualty markets, commercial premium rates or methods of compensation;

•our ability to implement initiatives intended to yield cost savings and the ability to achieve those cost savings; and

•the effects of Irish law on our operating flexibility and the enforcement of judgments against us.

Any or all of our forward-looking statements may turn out to be inaccurate, and there are no guarantees about our performance. The factors identified above are not exhaustive. Aon and its subsidiaries operate in a dynamic business environment in which new risks may emerge frequently. Accordingly, readers should not place undue reliance on forward-looking statements, which speak only as of the dates on which they are made. We are under no (and expressly disclaim any) obligation to update or alter any forward-looking statement that we may make from time to time, whether as a result of new information, future events, or otherwise. Further information about factors that could materially affect Aon, including our results of operations and financial condition, is contained in the “Risk Factors” section in Part I, Item 1A of this report.

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Table of Contents

PART I
	Item 1. Business
	Item 1A. Risk Factors
	Item 1B. Unresolved Staff Comments
	Item 2. Properties
	Item 3. Legal Proceedings
	Item 4. Mine Safety Disclosure
PART II
	Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities
	Item 6. [Reserve]
	Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations
	Item 7A. Quantitative and Qualitative Disclosures About Market Risk
	Item 8. Financial Statements and Supplementary Data
	Aon plc Consolidated Statements of Income
	Aon plc Consolidated Statements of Comprehensive Income
	Aon plc Consolidated Statements of Financial Position
	Aon plc Consolidated Statements of Shareholders' Equity
	Aon plc Consolidated Statements of Cash Flows
	Notes to Consolidated Financial Statements
	Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
	Item 9A. Controls and Procedures
	Item 9B. Other Information
	Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevents Inspections
PART III
	Item 10. Directors, Executive Officers and Corporate Governance
	Item 11. Executive Compensation
	Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters
	Item 13. Certain Relationships and Related Transactions, and Director Independence
	Item 14. Principal Accountant Fees and Services
PART IV
	Item 15. Exhibits and Financial Statement Schedules
	Item 16. Form 10-K Summary
SIGNATURES

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The below definitions apply throughout this report unless the context requires otherwise:

Term	Definition
ABO	Accumulated Benefit Obligation
AGI	Allianz Global Investors U.S. LLC
ASC	Accounting Standards Codification
BPS	Basis Points
CCC	Christchurch City Council
CODM	Chief Operating Decision Maker
CPI	Consumer Price Index
DCF	Discounted Cash Flow
DOJ	Department of Justice
E&O	Errors and Omissions
EBITDA	Earnings before Interest, Taxes, Depreciation, and Amortization
ERISA	Employee Retirement Income Security Act of 1974
ESG	Environmental, Social, Corporate Governance
E.U.	European Union
FASB	Financial Accounting Standards Board
FCA	Financial Conduct Authority
FINRA	Financial Industry Regulatory Authority
Fitch	Fitch, Inc.
GAAP	Generally Accepted Accounting Principles
GILTI	Global Intangible Low-Tax Income
HSR Act	Hart-Scott-Rodino Antitrust Improvements Act
I&D	Inclusion and Diversity
LOC	Letter of Credit
LPP	Leadership Performance Plan
MDI	Market Derived Income
NEBC	National Employee Benefits Committee
NYSE	New York Stock Exchange
OECD	Organization for Economic Co-operation and Development
PBO	Projected Benefit Obligation
PCAOB	Public Company Accounting Oversight Board
PSA	Performance Share Awards
REIT	Real Estate Investment Trusts
ROU	Right-of-use
RPGIC	Retirement Plan Governance and Investment Committee
RSU	Restricted Share Units
S&P	Standard & Poor’s
SEC	Securities and Exchange Commission
U.K.	United Kingdom
U.S.	United States
VIE	Variable Interest Entity
WTW	Willis Towers Watson Public Limited Company

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PART I

Item 1.    Business

OVERVIEW

Aon plc (which may be referred to as “Aon,” the “Company,” “we,” “us,” or “our”) is a leading global professional services firm providing a broad range of risk, health, and wealth solutions. Through our experience, global reach, and comprehensive analytics, we are better able to help clients meet rapidly changing, increasingly complex, and interconnected challenges. We are committed to accelerating innovation to address unmet and evolving client needs, so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business. Management is focused on strengthening Aon and uniting the firm with one portfolio of capability enabled by data and analytics and one operating model to deliver additional insight, connectivity, and efficiency.

Our clients are in over 120 countries and include all market segments and almost every industry. This diversification of our customer base helps provide us stability in different economic scenarios that could affect specific industries, customer segments, or geographies.

We have continued to focus our portfolio on higher-margin, capital-light professional services businesses that have high recurring revenue streams and strong cash flow generation. We endeavor to make capital allocation decisions based upon return on invested capital.

BUSINESS SEGMENT

The Company operates as one segment that includes all of Aon’s continuing operations, which, as a global professional services firm, provides advice and solutions to clients focused on risk, health and wealth through four principal products and services: Commercial Risk Solutions, Reinsurance Solutions, Health Solutions, and Wealth Solutions. Collectively, these products and service lines make up our one segment: Aon United. In addition, the Company is continuing to expand on Aon United growth initiatives through its New Ventures Group.

In 2021, our consolidated total revenue was $12,193 million. This includes $6,635 million in Commercial Risk Solutions, $1,997 million in Reinsurance Solutions, $2,154 million in Health Solutions, and $1,426 million in Wealth Solutions, before intercompany eliminations.

Principal Products and Services

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. In retail brokerage, our dedicated teams of risk professionals utilize comprehensive analytics capabilities and insights providing clients with risk advice for their organizations. We utilize Aon’s differentiated capabilities in industry sector- and segment-specific approaches to risk transfer options and deliver them through a variety of channels including bespoke solutions for complex needs, structured solutions for mid-market and small and medium-sized enterprises, and digital distribution including CoverWallet. Our specialty-focused organizational structure includes financial and professional lines, cyber, surety and trade credit, crisis management, transaction liability, and intellectual property. We develop market leading insights on the most efficient risk transfer vehicles for clients in today’s complex and integrated risk environment to enable clients to make better decisions. Global risk consulting and captive management is a global leader in supporting better management of companies’ risk profiles by identifying and quantifying the risks they face, mapping out optimal risk mitigation, retention and transfer solutions and thus enabling them to be more informed to make better decisions for their businesses. Affinity programs include development, marketing, and administration of customized and targeted insurance programs, facilities, and other structured solutions, including Aon Client Treaty. We collaborate with sponsors and other privileged distribution channels through which Aon can deliver differentiated, highly targeted, and highly valuable solutions for unique risk solutions.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, and capital markets. Treaty reinsurance addresses underwriting and capital objectives on a portfolio level, allowing our clients to more effectively manage the combination of premium growth, return on capital, and rating agency interests on an integrated basis. This includes the development of more competitive, innovative, and efficient risk transfer options. Facultative reinsurance empowers clients to better understand, manage, and transfer risk through innovative facultative solutions and provides the most efficient access to the global facultative reinsurance markets. Capital markets is a global investment bank with expertise in insurance-linked securities, capital raising, strategic advice, restructuring, and mergers and acquisitions. We partner with insurers, reinsurers, investment firms, and corporations in executing innovative risk management products, capital market solutions and corporate finance advisory services.

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Health Solutions includes consulting and brokerage, voluntary benefits and enrollment solutions, and human capital solutions. Consulting and brokerage develops and implements innovative, customized health and benefits strategies for clients of all sizes across industries and geographies to manage risk, drive engagement, and strengthen the workforce through improved health and well-being. We partner with insurers and other strategic partners to develop and implement new and innovative solutions and leverage world-class analytics and technology to help clients make informed decisions and manage healthcare outcomes. Consulting and brokerage also advises multinational companies on global benefits, including insurance placement across more than 120 countries, program design and management, financing optimization, and enhanced employee experience, as well as assists in navigating global regulatory and compliance requirements in countries in which they operate. Voluntary benefits and enrollment solutions designs and delivers innovative voluntary consumer benefits that improve an employer’s total rewards strategy and positively impacts their employees’ financial and overall well-being. We leverage our proprietary digital platform to provide efficient enrollment strategies through an effective combination of data, analytics, and tailored products. Multi-channel and targeted communications solutions increase consumer benefit knowledge and enhance engagement. Our human capital team delivers data, analytics, and advice to business leaders so they can make better workforce decisions and align their business and people strategies. We support clients across the full employee lifecycle, including talent assessment and selection, compensation benchmarking, total rewards strategy optimization, workforce analytics and benchmarking, workforce resilience planning, human capital integration in transaction situations, Corporate Governance, ESG consulting and strategic employee communication.

Wealth Solutions includes retirement consulting, pension administration, and investments consulting. Retirement consulting specializes in providing clients across the globe with strategic design consulting on their retirement programs, actuarial services, and risk management, including pension de-risking, governance, integrated pension administration and legal and compliance consulting. We also help organizations manage their balance sheet volatility. Retirement consulting and pension administration leverage Aon’s pension expertise to deliver high-quality integrated retirement services. Our customized services include outsourcing, co-sourcing and in-sourcing options. Our partnership-driven model is powered by deep pension experience and enabled with smart technology. Our investments consulting team provides public and private companies and other institutions with advice on developing and maintaining investment programs across a broad range of plan types, including defined benefit plans, defined contribution plans, endowments and foundations. Our delegated investment solutions offer ongoing management of investment programs and fiduciary responsibilities either in a partial or full discretionary model for multiple asset owners. We partner with clients to deliver our scale and experience to help them effectively manage their investments, risk, and governance and potentially lower costs. We believe in the power of connecting participants to experts to make better informed and smarter decisions about their wealth.

Revenue and Compensation

Our business generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services we provide to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which we act. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services, and (2) fees and commissions for administrative and other services provided to or on behalf of insurers and reinsurers. Fees from clients for advice and consulting services are dependent on the extent and value of the services we provide. Payment terms are consistent with current industry practices.

Funds Held on Behalf of Clients

We typically hold funds on behalf of clients, including premiums received from clients and claims due to clients that are in transit to and from insurers. Certain funds held on behalf of clients are invested in interest-bearing premium trust accounts and can fluctuate significantly depending on when we collect and remit cash. The principal is segregated and not available for general operating purposes, although we may earn interest on these accounts.

Competition

Our business operates in a highly competitive and fragmented environment. We compete with numerous other global insurance brokers and consulting companies, including Marsh & McLennan Companies, Inc., WTW, Arthur J Gallagher & Company, and Lockton Companies, Inc., as well as numerous other global specialist, regional, and local firms in almost every area of our business. We also compete with insurance and reinsurance companies that directly market and service their insurance products without the assistance of brokers or agents. Additionally, we compete with other businesses that do not fall into the categories above, including large financial institutions and independent consulting firms and consulting organizations affiliated with accounting, information systems, technology, and financial services firms.

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Seasonality

Due to buying patterns and delivery of certain products and services in the markets we serve, revenues recognized tend to be higher in the first and fourth quarters of each fiscal year.

Licensing and Regulation

Our business activities are subject to licensing requirements and extensive regulation under the laws of countries in which we operate, including U.S. federal and state laws. See the “Risk Factors” section in Part I, Item 1A of this report for information regarding how actions by regulatory authorities or changes in legislation and regulation in the jurisdictions in which we operate may have an adverse effect on our business.

Regulatory authorities in the U.S. and most other countries in which our operating subsidiaries conduct business may require individuals, entities and related service providers to obtain a license from a government agency, including (but not limited to) licenses to operate as insurance producers, brokers, agents, and consultants, reinsurance brokers or managing general agents.

Certain jurisdictions issue licenses only to resident entities or individuals. In such jurisdictions, if the Company has no licensed subsidiary, we may maintain arrangements with residents or business entities licensed to act in such jurisdiction. Such arrangements are subject to an internal review and approval process.

Our subsidiaries must comply with laws and regulations of the jurisdictions in which they do business. These laws and regulations are enforced by the FCA in the U.K., by federal and state agencies in the U.S., and by various regulatory agencies and other supervisory authorities in other countries through the granting and revoking of licenses to do business, the licensing of agents, the monitoring of trade practices, policy form approval, limits on commission rates, and mandatory remuneration disclosure requirements.

Insurance authorities in the U.K., U.S., and certain other jurisdictions in which our subsidiaries operate have enacted laws and regulations governing the investment of funds, such as premiums and claims proceeds, held in a fiduciary capacity for others. These laws and regulations generally require the segregation of these fiduciary funds and limit the types of investments that may be made with them.

Investment, securities, and futures licensing authorities also govern certain business activities. For example, in the U.S., we use Aon Securities LLC, an indirect, wholly owned subsidiary of Aon, and a U.S.-registered broker-dealer and investment advisor, member of FINRA and Securities Investor Protection Corporation, for investment banking, capital advisory services and other broker-dealer activities. Similar operations exist in other jurisdictions outside of the U.S.

Further, pension and financial laws and regulations, including oversight and supervision by the FCA in the U.K., the SEC in the U.S., and regulators in other countries govern certain of the retirement-related consulting services provided by Aon and its subsidiaries and affiliates. This includes Aon subsidiaries that provide investment advisory services regulated by various U.S. federal authorities including the SEC and FINRA, as well as authorities on the state level. In addition, other services provided by Aon and its subsidiaries and affiliates, such as trustee services and retirement and employee benefit program administrative services, are subject in various jurisdictions to pension, investment, securities, and insurance laws and regulations, and supervision.

Clientele

Our clients operate in many businesses and industries throughout the world. No one client accounted for more than 2% of our consolidated total revenues in 2021. Additionally, we place insurance with many insurance carriers, none of which individually accounted for more than 10% of the total premiums we placed on behalf of our clients in 2021.

Human Capital Management

Our Culture

Our culture is driven by our values – committed as one firm to our purpose, united through trust as one inclusive, diverse team, and passionate about making our colleagues and clients successful. Our colleagues are the cornerstone of Aon's success. Collaboration and innovation drive our culture, bringing the best of Aon to clients in a holistic and seamless manner. Our Delivering Aon United strategy defines how Aon colleagues work together to deliver value to clients, setting a new standard for client leadership. Delivering Aon United is brought to life through our common client value creation model which scales strategies from across the firm to bring the best of Aon to clients.

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Colleagues

As of December 31, 2021, we employed approximately 50,000 employees and conducted our operations in more than 120 countries and territories. Our colleagues’ diverse talents, expertise, and insights contribute to the success of both our firm and our clients, and we seek to attract, grow, and retain the best talent in the industry. Our Inclusive People Leadership strategy is a central part of our Aon United Blueprint and is a key enabler to realizing our aspirations and purpose as a firm. At Aon, all colleagues are called upon to be leaders in embracing and modelling our Aon United values and behaviors. Inclusive People Leadership at Aon ensures that all colleagues – at every stage of their career journey – are equipped and motivated to deliver on our purpose and able to achieve their full potential.

Training and Development

We invest significant resources to develop the talent needed to remain at the forefront of innovation and make Aon an attractive employer. Colleagues are invited to complete a variety of curricula to meet their career stage goals and developmental needs. We provide our colleagues what they need to learn, grow, and become the leaders our clients seek. From self-guided Aon University courses to advanced learning programs, the curriculum is aligned to the Aon United Blueprint and Inclusive People Leader strategy. While the COVID-19 pandemic changed how our colleagues work and collaborate, it did not slow us down. Aon’s investment in technology and use of virtual based learning and development programs during the pandemic has allowed us to continue these efforts despite much of our workforce remaining virtual during 2021.

Colleague Engagement and Retention

Providing an engaging and rewarding colleague experience is a top priority for our firm and understanding colleagues’ feedback helps us reach that goal. We use a variety of channels to facilitate open, on-going, and direct communication with colleagues. These channels include open forums and town halls with executives, surveys, and engagement through our Business Resource Groups. Business Resource Groups are our independent, voluntary, non-profit associations that provide input, take action, and help identify opportunities for our firm to further its diversity and inclusion commitments.

In response to the challenging events of 2020, we updated our engagement survey process by offering more frequent pulse surveys to understand how colleagues are engaging with their teams, the firm, and clients. This outreach effort allows us to gather insights more rapidly and take timely action to address feedback. Our current practice is to conduct pulse surveys with subsets of the overall colleague population approximately six to eight times per year on timely or targeted issues, as well as an annual all-colleague engagement survey. The pulse surveys for 2021 were focused on topics such as manager and leadership support, especially in how we serve clients, colleague well-being, inclusion and diversity, and performance & rewards. Aon’s workforce feedback provides management a better understanding of evolving colleague viewpoints, and ensures we are taking appropriate steps to drive colleague engagement and retention. For discussion of the risks related to the attraction and retention of senior management and other professional personnel, see the “Risk Factors” section in Part I, Item 1A of this report.

Rewards

In addition to an inspired purpose and culture, we are proud to offer our colleagues a total rewards program that combines competitive pay, incentive opportunities, and benefits. Our compensation programs, including salary, recognition, cash and equity incentives, connect to our formal performance management and career development approach. These programs serve to reward colleagues for their impact both in what they accomplish for clients, colleagues, and shareholders and how they achieve those results. We maintain a global commitment to colleague well-being and play a key role in supporting colleagues across the physical, emotional, financial, and social spectrum. Our comprehensive benefit programs are competitive for the markets in which we operate and aligned with our values and culture.

In recognition of our colleagues’ role in growing the firm, we introduced the Aon United Growth Ownership Plan in 2021. Through the plan, all eligible colleagues that were active on September 24, 2021, received a one-time, stock-based award, enabling Aon colleagues to share in the future success of our Aon United mission.

Our compensation philosophy aligns with our Aon United strategy and delivering long-term shareholder value creation. Our executive incentives are based on driving results, delivery of strategic initiatives, and leadership. Beginning in 2021, 20% of the short-term incentives for senior executives are based on quantifiable performance against firm-wide Inclusion and Diversity initiatives.

Inclusion and Diversity

We believe that diverse, inclusive teams produce better insight, better solutions, and ultimately the best outcomes for clients and Aon’s long-term success.

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We are focused on being a firm that is representative of the communities in which we operate. We achieve this by aligning I&D actions to the following pillars: Recruitment, Education, Promotion, and Representation. We strongly believe that only when colleagues can be their authentic selves will they reach their full potential.

Our commitment to I&D starts from the top with our Board of Directors, including its I&D Sub-Committee. Our Global Inclusive Leadership Council is sponsored by our Chief Executive Officer and Chief People Officer. Regional Inclusive Leadership Councils and our Executive Leadership Teams drive actions to increase the diversity of our teams, and colleague-led Business Resource Groups support execution and provide additional opportunities for colleagues to enhance our inclusive environment.

As of December 31, 2021, Aon’s global workforce was 54% women and 46% men, and the Aon Executive Committee which leads the firm was 45% women and 55% men. At the manager level, 26% of senior leaders and 42% of managers with one or more direct report were women. New colleague hires for the year were 52% women and 48% men. Aon’s U.S. workforce was 24% racially or ethnically diverse, calculated as a percentage of colleagues that have voluntarily disclosed their race or ethnicity to Aon. At the manager level, 13% of U.S. senior leaders and 17% of U.S. managers with one or more direct report were racially or ethnically diverse. New colleague hires for the year in the U.S. were 34% racially or ethnically diverse.

Our Apprenticeship Program

Apprenticeship programs help build a talent pipeline of highly skilled and diverse professionals while providing apprentices with advanced education and work experience. By removing some of the traditional barriers to entry-level employment, Aon can contribute to local workforce development and cultivate talent while improving retention rates in these entry-level roles. As a founding member of six apprentice networks within the U.S., we partner with companies and organizations to assist them in building their own programs through sharing best practices and learnings. Across these networks, we have over 100 organizations committed as of December 31, 2021.

Aon's two-year Apprenticeship Program, which was implemented in the U.K. and U.S. in 2012 and 2017, respectively, serves as an alternate route into a permanent role that normally requires a specific degree or professional experience. Aon provides motivated, high-potential individuals with the required training (on the job and in the classroom), professional skills development, mentorship, and experiential learning to bridge the gap. Over 440 Aon apprentices have been hired since the inception of the program across the U.S. and U.K. Both programs are certified apprenticeship programs, by the Department of Labor in the U.S. and the Department of Education in the U.K. In 2021, we expanded our U.S. program to include additional U.S. cities outside of Chicago's metropolitan area to the following six metropolitan areas hiring over 100 apprentices and partnering with seven additional community colleges: Houston, Minneapolis, New York, Philadelphia, San Francisco, and Washington, DC.

Website Access to Reports and Other Information

Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and all amendments to those reports are made available free of charge through our website (http://www.aon.com) as soon as reasonably practicable after such material is electronically filed with or furnished to the SEC. Also posted on our website are the charters for our Audit, Organization and Compensation, Governance/Nominating, and Finance Committees, and Compliance and Inclusion & Diversity Sub-Committees, our Governance Guidelines, and our Code of Business Conduct. Within the time period required by the SEC and the NYSE, we will post on our website any amendment to or waiver of the Code of Business Conduct applicable to any executive officer or director. In addition, we may announce material information to investors and the marketplace using our investor relations website. While not all of the information that we post to such website is of a material nature, some information could be deemed to be material. Accordingly, we encourage investors, the media, and others interested in our company to review the information that we share at our investor relations link located at the bottom of the page on www.aon.com. The information provided on our website is not part of this report and is therefore not incorporated herein by reference.

Item 1A.    Risk Factors

The risk factors set forth below reflect risks associated with our existing and potential businesses and the industries in which we operate generally and contain “forward-looking statements” as discussed in the “Business” Section of Part I, Item 1 of this report. Readers should consider these risks in addition to the other information contained in this report because our business, financial condition, or results of operations could be materially adversely affected if any of these risks were to actually occur and the occurrence of such risks could cause our actual results to differ materially from those stated in or implied by the forward-looking statements in this document and elsewhere.

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Risks Related to Our Business

An overall decline in economic and business activity could have a material adverse effect on the financial condition and results of operations of our business.

The results of our operations are generally affected by the level of business activity of our clients, which in turn is affected by the economy of the industries and markets these clients serve. Economic downturns, volatility, or uncertainty in the broader economy or in specific markets (including as a result of endemics or pandemics, climate change, political unrest, or otherwise) may cause reductions in technology and discretionary spending by our clients, which may result in reductions in the growth of new business or reductions in existing business. If our clients become financially less stable, enter bankruptcy, liquidate their operations or consolidate, our revenues and collectability of receivables could be adversely affected.

The demand for property and casualty insurance generally rises as the overall level of economic activity increases and generally falls as such activity decreases, affecting both the commissions and fees generated by our Commercial Risk Solutions, Reinsurance Solutions, and Wealth Solutions lines. The economic activity that impacts property and casualty insurance is most closely correlated with employment levels, corporate revenues, and asset values. Downward fluctuations in the year-over-year insurance premiums charged by insurers to protect against the same risk, referred to in the industry as softening of the insurance market, could adversely affect these businesses as a significant portion of the earnings are determined as a percentage of premiums charged to our clients. In addition, certain discretionary services within our business, such as Human Capital, project-related work within Commercial Risk Solutions and Health Solutions, and transaction liability, may see a decrease in activity if the overall level of economic activity results in a reduction to our clients’ discretionary spending. Insolvencies and consolidations associated with an economic downturn, especially insolvencies in the insurance industry, could adversely affect our brokerage business through the loss of clients by hampering our ability to place insurance and reinsurance business. Also, error and omission claims against us, which we refer to as E&O claims, may increase in economic downturns, also adversely affecting our business.

We face significant competitive pressures from traditional and non-traditional competitors that could affect our business.

As a global professional services firm, we compete with global, national, regional, and local insurance companies that market and service their own products, other financial services providers, brokers, and investment managers, independent firms, and consulting organizations affiliated with accounting, information systems, technology, and financial services firms. We compete with respect to service, delivery of insights, product features, price, commission structure, technology, financial strength, ability to access certain insurance markets, and name recognition. Our competitors may have better financial, technical and marketing resources, broader customer bases, greater name recognition, more comprehensive products, stronger presence in certain geographies, or more established relationships with their customers and suppliers than we have.

In addition, alliances among competitors or mergers of competitors could affect our business, and some of our competitors may have or may develop a lower cost structure, adopt more aggressive pricing policies, or provide services that gain greater market acceptance than the services that we offer or develop.

Our competitors may be more successful in innovating and delivering services to meet new and existing client needs. Competitors may be able to respond to the need for technological changes, innovate faster, respond better to evolving client demand and industry conditions, or price their services more aggressively than we do. They may also compete for skilled professionals, finance acquisitions, fund internal growth, and compete for business more effectively than we do. Further, new and non- traditional competitors, our clients’ increasing ability and determination to self-insure, and capital market alternatives to traditional insurance and reinsurance markets cause additional forms of competition and innovation that could affect our business. This competition is further intensified by an industry trend where clients elect to engage multiple brokers to service different portions of their accounts. If we fail to respond successfully to the to the evolving competition we face, our financial condition or results of operations might be adversely affected.

If our clients are not satisfied with our services, we may face additional cost, loss of profit opportunities, damage to our reputation, or legal liability.

We depend, to a large extent, on our relationships with our clients and our reputation for high-quality advice and solutions. If a client is not satisfied with our services, it could cause us to incur additional costs and impair profitability, or lose the client relationship altogether. Moreover, if we fail to meet our contractual obligations, we could be subject to legal liability or loss of client relationships.

The nature of much of our work involves assumptions and estimates concerning future events, the actual outcome of which we cannot know with certainty in advance. For example, in our investment consulting business, we may be measured based on our track record regarding judgments and advice on investments that are susceptible to influences unknown at the time the advice was given. In addition, we could make computational, software programming, or data entry or management errors. A

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client may claim it suffered losses due to reliance on our consulting advice, which poses risks of liability exposure and costs of defense and increased insurance premiums. Many of our clients are businesses that actively share information among themselves about the quality of service they receive from their vendors. Accordingly, poor service to one client may negatively impact our relationships with multiple other clients.

Damage to our reputation could have a material adverse effect on our business.

We advise our clients on and provide services related to a wide range of subjects and our ability to attract and retain clients is highly dependent upon the external perceptions of our level of service, trustworthiness, business practices, financial condition, and other subjective qualities. Negative perceptions or publicity regarding these matters or others could erode trust and confidence and damage our reputation among existing and potential clients and existing and future employees, which could make it difficult for us to attract new clients and employees and retain existing ones. Negative public opinion could also result from actual or alleged conduct by us or those currently or formerly associated with us. Damage to our reputation, including as a result of negative perceptions or publicity regarding environmental matters, climate change, workforce diversity, pay equity, harassment, social justice, cyber security or data privacy, or our inability to meet commitments or client and stakeholder expectations with respect to such matters, could affect the confidence of our clients, rating agencies, regulators, stockholders, employees and third parties in transactions that are important to our business adversely affecting our business, financial condition, and operating results.

Revenues from commission arrangements may fluctuate due to many factors, including cyclical or permanent changes in the insurance and reinsurance markets outside of our control.

Revenues from commission arrangements have historically been affected by significant fluctuations arising from uncertainties and changes in the industries in which we operate. A significant portion of our revenue consists of commissions paid to us out of the premiums that insurers and reinsurers charge our clients for coverage. We have no control over premium rates, and our revenues and profitability are subject to change to the extent that premium rates fluctuate or trend in a particular direction. The potential for changes in premium rates is significant, due to pricing cyclicality in the commercial insurance and reinsurance markets.

In addition to movements in premium rates, our ability to generate premium-based commission revenue may be challenged by:

•the growing availability of alternative methods for clients to meet their risk-protection needs, including a greater willingness on the part of corporations to “self-insure,” the use of so-called “captive” insurers, and the development of capital markets-based solutions and other alternative capital sources for traditional insurance and reinsurance needs that increase market capacity, increase competition, and put pressure on pricing;

•fluctuation in the need for, or relevancy of, insurance;

•the level of compensation, as a percentage of premium, that insurance carriers are willing to compensate brokers for placement activity;

•the growing desire of clients to move away from variable commission rates and instead compensate brokers based upon flat fees, which can negatively impact us as fees are not generally indexed for inflation and may not rise as much as commission-based compensation;

•competition from insurers seeking to sell their products directly to consumers, including online sales, without the involvement of an insurance broker; and

•growing number of technology-enabled competitors offering new risk-transfer solutions that eliminate the traditional broker-client relationship in both commercial insurance and reinsurance markets.

The profitability of our operations may not meet our expectations due to unexpected costs, cost overruns, inflation, early contract terminations, unrealized assumptions used in our contract bidding process or the inability to maintain our prices.

Our profitability is highly dependent upon our ability to control our costs and improve our efficiency. As we adapt to changes in our business and the market, adapt to the regulatory environment, enter into new engagements, acquire additional businesses, and take on new employees in new locations, we may not be able to manage our large, diverse and changing workforce, control our costs, or improve our efficiency.

Our profit margin, and therefore our profitability, is largely a function of the revenue generated from our services and the staffing costs for our personnel. Accordingly, if we are not able to maintain the rates we charge for our services or appropriately manage the staffing costs of our personnel, we may not be able to sustain our profit margin and our profitability will suffer. The

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prices we are able to charge for our services are affected by a number of factors, including competitive factors, the extent of ongoing clients’ perception of our ability to add value through our services, and general economic conditions. If we cannot drive suitable cost efficiencies, our profit margins will suffer. Our cost efficiencies may also be impacted by factors such as our ability to transition consultants from completed projects to new assignments, our ability to secure new business, our ability to forecast demand for our services (and, consequently, appropriately manage the size and location of our workforce), employee attrition, inflation (including wage inflation) and the need to devote time and resources to training and professional and business development.

In our investment consulting business, we advise or act on behalf of clients regarding their investments. The results of these investments are uncertain and subject to numerous factors, some of which are within our control and some which are not. Clients that experience losses or lower than expected investment returns may leave us for competitors and/or assert claims against us.

Our investment consulting business provides advice to clients on: investment strategy, which can include advice on setting investment objectives, asset allocation, and hedging strategies; selection (or removal) of investment managers; the investment in different investment instruments and products; and the selection of other investment service providers such as custodians and transition managers. For some clients, we are responsible for making decisions on these matters and we may implement such decisions in a fiduciary or agency capacity without assuming title over the underlying funds or assets invested. Asset classes may experience poor absolute performance and third parties we recommend or select, such as investment managers, may underperform their benchmarks due to poor market performance, negligence, or other reasons, resulting in poor investment returns or losses. These losses may be attributable in whole or in part to failures on our part or to events entirely outside of our control, including but not limited to uncertainty or volatility in financial markets due to economic, political, and regulatory conditions or pandemics. Plaintiffs have, and may continue to, file individual and class action lawsuits alleging investment consultants have charged excessive fees, given improper advice due to conflicts of interest, or recommended investments that underperformed other investments available at the time. Defending against these claims can involve potentially significant costs, including legal defense costs, as well as cause substantial distraction and diversion of other resources. If any lawsuit – against the Company or any other investment consultant – results in a large adverse verdict, the size of the verdict or resultant negative adverse publicity may prompt the filing of additional lawsuits. Furthermore, our ability to limit our potential liability is restricted in certain jurisdictions and in connection with claims involving breaches of fiduciary or agency duties or other alleged errors or omissions.

The anticipated benefits of the redomiciliation from the U.K. to Ireland may not be realized.

In April 2020, we changed the jurisdiction of incorporation for our parent company from the U.K. to Ireland by means of a scheme of arrangement under English law (the “Reorganization”). At the time of the Reorganization we expected, and we continue to expect, that the Reorganization will, among other things, provide greater certainty around ongoing access to existing U.S. treaties with other EU member countries from which we derive benefit. However, we may not realize the benefits we anticipate from the Reorganization, which could have an adverse effect on our business.

Financial Risks

We are exposed to fluctuations in currency exchange rates that could negatively impact our financial results and cash flows.

We face exposure to adverse movements in exchange rates of currencies other than our reporting currency, the U.S. dollar, as a significant portion of our business is located outside of the U.S. These exposures may change over time, and they could have a material adverse impact on our financial results and cash flows. Approximately 55% of our consolidated revenue is non-U.S., attributed on the basis of where the services are performed, and where products are sold, and the exposures created can have significant currency volatility. These currency exchange fluctuations create risk in both the translation of the financial results of our global subsidiaries into U.S. dollars for our consolidated financial statements, as well as in those of our operations that receive revenue and incur expenses other than in their respective local currencies, which can reduce the profitability of our operations based on the direction the respective currencies’ exchange rates move. A decrease in the value of certain currencies relative to other currencies could place us at a relative disadvantage compared to our competitors that benefit to a greater degree from a specific exchange rate move and can, as a result, deliver services at a lower cost or receive greater revenues from such a transaction. Although we use various derivative financial instruments to help protect against certain adverse foreign exchange rate fluctuations, we cannot eliminate such risks, and, as a result, changes in exchange rates may adversely affect our results. For example, the strengthening of the value of the U.S. dollar versus other currencies might adversely affect the value of our products and services when translated to U.S. dollar, even if the value of such products and services has not changed in their original currency.

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Changes in interest rates and deterioration of credit quality could reduce the value of our cash balances and investment portfolios and adversely affect our financial condition or results.

Operating funds available for corporate use were $836 million at December 31, 2021 and are reported in Cash and cash equivalents and Short-term investments. Of the total balance, $160 million was restricted to its use as of December 31, 2021. Funds held on behalf of clients and insurers were $6.1 billion at December 31, 2021 and are reported in Fiduciary assets. We also carry an investment portfolio of other long-term investments. As of December 31, 2021, these long-term investments had a carrying value of $64 million. Adverse changes in interest rates, performance, and counterparty credit quality, including default, could reduce the value of these funds and investments, thereby adversely affecting our financial condition or results. We may experience reduced investment earnings on our cash and short-term investments of fiduciary and operating funds if the yields on investments deemed to be low risk remain at or near their current low levels or fall below their current levels, or if negative yields on deposits or investments are experienced, as we have experienced in Japan and certain jurisdictions in the E.U. On the other hand, higher interest rates could result in a higher discount rate used by investors to value our future cash flows thereby resulting in a lower valuation of the Company. In addition, during times of stress in the banking industry, counterparty risk can quickly escalate, potentially resulting in substantial losses for us as a result of our cash or other investments with such counterparties, as well as substantial losses for our clients and the insurance companies with which we work.

Our pension obligations and value of our pension assets could adversely affect our shareholders’ equity, net income, cash flow, and liquidity.

To the extent that the pension obligations associated with our pension plans continue to exceed the fair value of the assets supporting those obligations, our financial position and results of operations may be adversely affected. In particular, lower interest rates and investment returns could result in the present value of plan liabilities increasing at a greater rate than the value of plan assets, resulting in higher unfunded positions in our pension plans. In addition, the periodic revision of pension assumptions or variances of actual results from our assumptions can materially change the present value of expected future benefits, and therefore the funded status of the plans and resulting net periodic pension expense. As a result, we may experience future changes in the funded status of our plans that could require us to make additional cash contributions beyond those that have been estimated and which could adversely affect shareholders’ equity, net income, cash flow and liquidity.

Our worldwide pension plans are significant, and therefore our pension contributions and expense are sensitive to various market, demographic, and other factors. These factors include equity and bond market returns, fair value of pension assets, the assumed interest rates we use to discount our pension liabilities, foreign exchange rates, rates of inflation, mortality assumptions, potential regulatory and legal changes or developments, and counterparty exposure from various investments and derivative contracts, including annuities. Variations or developments in connection with any of these factors could cause significant changes to our financial position and results of operations from year to year. In addition, contributions are generally based on statutory requirements and local funding practices, which may differ from measurements under U.S. GAAP.

We have debt outstanding that could adversely affect our financial flexibility.

As of December 31, 2021, we had total consolidated debt outstanding of approximately $9.4 billion. The level of debt outstanding could adversely affect our financial flexibility by reducing our ability to use cash from operations for other purposes, including working capital, dividends to shareholders, share repurchases, acquisitions, capital expenditures and general corporate purposes. We also are subject to risks that, at the time any of our outstanding debt matures, we will not be able to retire or refinance the debt on terms that are acceptable to us, or at all.

As of December 31, 2021, we had two committed credit facilities outstanding. Each of these facilities is intended to support our commercial paper obligations and our general working capital needs. In addition, each of these facilities included customary representations, warranties, and covenants, including financial covenants that require us to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, tested quarterly.

A substantial portion of our outstanding debt, including certain intercompany debt obligations, contains financial and other covenants. The terms of these covenants may limit our ability to obtain, or increase the costs of obtaining, additional financing to fund working capital, capital expenditures, acquisitions, or general corporate requirements. This in turn may have the impact of reducing our flexibility to respond to changing business and economic conditions, thereby placing us at a relative disadvantage compared to competitors that have less indebtedness, or fewer or less onerous covenants associated with such indebtedness, and making us more vulnerable to general adverse economic and industry conditions.

If we cannot service our indebtedness, we may have to take actions such as selling assets, seeking additional equity, or reducing or delaying capital expenditures, strategic acquisitions, investments, and alliances, any of which could impede the implementation of our business strategy or prevent us from entering into transactions that would otherwise benefit our business.

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Additionally, we may not be able to take such actions or refinance any of our debt, if necessary, on commercially reasonable terms, or at all.

A decline in the credit ratings of our senior debt and commercial paper may adversely affect our borrowing costs, access to capital, and financial flexibility.

A downgrade in the credit ratings of our senior debt and commercial paper could increase our borrowing costs, reduce or eliminate our access to capital, reduce our financial flexibility, and limit our ability to implement on corporate strategy. Our senior debt ratings at December 31, 2021 were A- with a stable outlook S&P, BBB+ with a stable outlook (Fitch), and Baa2 with a stable outlook (Moody’s). Our commercial paper ratings were A-2 (S&P), F-2 (Fitch) and P-2 (Moody’s).

Real or anticipated changes in our credit ratings will generally affect any trading market for, or trading value of, our securities. Such changes could result from any number of factors, including the modification by a credit rating agency of the criteria or methodology it applies to particular issuers, a change in the agency’s view of us or our industry, or as a consequence of actions we take to implement our corporate strategies. A change in our credit rating could adversely limit our access to capital and our competitive position.

Our global effective tax rate is subject to a variety of different factors, which could create volatility in that tax rate, expose us to greater than anticipated tax liabilities or cause us to adjust previously recognized tax assets and liabilities.

We are, and anticipate we will be, subject to income taxes in Ireland, the U.K., the U.S. and many other jurisdictions. As a result, our global effective tax rate from period to period can be affected by many factors, including changes in tax legislation or regulations, the continuing development of regulations and other governmental action that affect the application of such legislation, our global mix of earnings, the use of global funding structures, the tax characteristics of our income, the effect of complying with transfer pricing requirements under laws of many different countries on our revenues and costs, the consequences of acquisitions and dispositions of businesses and business segments. In addition, we could be subject to increased taxation as a result of changes in eligibility for the benefits of current income tax treaties between and among Ireland, the U.K., the U.S and other countries, including any future amendments to the current income tax treaties between and among such countries, or any new statutory or regulatory provisions that might limit our ability to take advantage of any such treaties. Significant judgment is required in determining our worldwide provision for income taxes, and our determination of the amount of our tax liability is always subject to review by applicable tax authorities. Our actual global tax rate may vary from our expectation and that variance may be material.

The overall tax environment in the jurisdictions in which we are or may be subject to taxes is highly uncertain and increasingly complex. Countries around the world are considering changes in their tax laws and regulations. In the U.S., various proposals to raise corporate income taxes are under active consideration, which could have a material adverse effect on our effective tax rate, results of operations, cash flows and financial condition. The OECD, a global coalition of member countries, proposed a plan to reform international taxation which includes the introduction of a global minimum tax. There remains significant uncertainty as to if, when and how the various OECD proposals will ultimately be enacted in the various countries in which Aon is or may be subject to taxes, including the E.U. member states, and, if enacted, the extent of their impact. Some of the proposals, if enacted, could have a material adverse effect on our effective tax rate, results of operations, cash flows and financial condition.

We are, and anticipate we will be, subject to tax audits conducted by Ireland, the U.K., the U.S., and other tax authorities, and the resolution of such audits could impact our tax rate in future periods, as would any reclassification or other changes (such as those in applicable accounting rules) that increases the amounts we have provided for income taxes in our consolidated financial statements. The tax laws and regulations in Ireland, the U.K., the U.S., and the other tax jurisdictions in which the we operate are inherently complex, and we will be obligated to make judgments and interpretations about the application of these laws and regulations to our operations and businesses. The interpretation and application of these laws and regulations could be challenged by the relevant governmental authorities, which could result in administrative or judicial procedures, actions or sanctions, which could be material.

There can be no assurance that we would be successful in attempting to mitigate the adverse impacts resulting from any changes in tax laws and regulations, including any changes in the interpretation of such tax authorities, or from audits and other matters. Our inability to mitigate the negative consequences of such actions could cause our global effective tax rate to increase, our use of cash to increase and our financial condition and results of operations to suffer.

Changes in our accounting estimates and assumptions could negatively affect our financial position and results of operations.

We prepare our consolidated financial statements in accordance with U.S. GAAP. These accounting principles require us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets

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and liabilities at the date of our consolidated financial statements. We are also required to make certain judgments that affect the reported amounts of revenues and expenses during each reporting period. We periodically evaluate our estimates and assumptions including, but not limited to, those relating to revenue recognition, pensions, recoverability of assets including customer receivables, valuation of goodwill and intangibles, contingencies, share-based payments, and income taxes. We base our estimates on historical experience and various assumptions that we believe to be reasonable based on specific circumstances. These assumptions and estimates involve the exercise of judgment and discretion, which may evolve over time in light of operational experience, regulatory direction, developments or changes in accounting principles or standards, and other factors. Actual results could differ from these estimates, or changes in assumptions, estimates, policies, or developments in the business may change our initial estimates, which could materially affect the Consolidated Statements of Income, Comprehensive Income, Financial Position, Shareholders’ Equity, and Cash Flows.

We may be required to record goodwill or other long-lived asset impairment charges, which could result in a significant charge to earnings.

Under U.S. GAAP, we review our long-lived assets for impairment when events or changes in circumstances indicate the carrying value may not be recoverable. Goodwill is assessed for impairment at least annually. Factors that may be considered in assessing whether goodwill or other long-lived assets may not be recoverable include a decline in our share price or market capitalization, reduced estimates of future cash flows and slower growth rates in our industry. We may experience unforeseen circumstances that adversely affect the value of our goodwill or other long- lived assets and trigger an evaluation of the recoverability of the recorded goodwill and other long-lived assets. Future goodwill or other long-lived asset impairment charges could materially impact our consolidated financial statements.

We are a holding company and, therefore, may not be able to receive dividends or other payments in needed amounts from our subsidiaries.

The Company is organized as a holding company, a legal entity separate and distinct from our operating entities. As a holding company without significant operations of its own, our principal assets are the shares of capital stock of our subsidiaries. We rely on dividends, interest, and other payments from these subsidiaries to meet our obligations for paying principal and interest on outstanding debt, paying dividends to shareholders, repurchasing ordinary shares, and corporate expenses. Certain of our subsidiaries are subject to regulatory requirements of the jurisdictions in which they operate or other restrictions that may limit the amounts that subsidiaries can pay in dividends or other payments to us. No assurance can be given that there will not be further changes in law, regulatory actions, or other circumstances that could restrict the ability of our subsidiaries to pay dividends or otherwise make payments to us. Furthermore, no assurance can be given that our subsidiaries may be able to make timely payments to us in order for us to meet our obligations.

Legal and Regulatory Risks

We are subject to E&O claims against us as well as other contingencies and legal proceedings, some of which, if determined unfavorably to us, could have a material adverse effect on our financial condition or results of operations.

We assist our clients with various matters, including advising on and placing insurance and reinsurance coverage and handling related claims, consulting on various human resources matters, and providing actuarial, investment consulting, and asset management services. E&O claims against us may allege our potential liability for damages arising from these services. E&O claims could include, for example, the failure of our employees or sub-agents, whether negligently or intentionally, to place coverage correctly or notify carriers of claims on behalf of clients, to provide insurance carriers with complete and accurate information relating to the risks being insured, or the failure to give error-free consulting or investment advice. It is not always possible to prevent and detect E&O, and the precautions we take may not be effective in all cases. In addition, we are subject to other types of claims, litigation, and proceedings in the ordinary course of business, which along with E&O claims, may seek damages, including punitive damages, in amounts that could, if awarded, have a material adverse impact on the Company’s financial position, earnings, and cash flows. In addition to potential liability for monetary damages, such claims or outcomes could harm our reputation or divert management resources away from operating our business.

We have historically purchased, and intend to continue to purchase, insurance to cover E&O claims and other insurance to provide protection against certain losses that arise in such matters. However, we have exhausted or materially depleted our coverage under some of the policies that protect us for certain years and, consequently, are self-insured or materially self-insured for some historical claims. Additionally, parts or all of an E&O claim could fall within insurance deductibles, self-insured retentions, or policy exclusions. Accruals for these exposures, and related insurance receivables, when applicable, have been provided to the extent that losses are deemed probable and are reasonably estimable. These accruals and receivables are adjusted from time to time as developments warrant and may also be adversely affected by disputes we may have with our insurers over coverage. Amounts related to settlement provisions are recorded in Other general expenses in the Consolidated

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Statements of Income. Discussion of some of these claims, lawsuits, and proceedings are contained in the Notes to Consolidated Financial Statements.

In addition, we provide a variety of guarantees and indemnifications to our customers and others. In the event of a default, our potential exposure is equal to the amount of the guarantee or indemnification.

The ultimate outcome of claims, lawsuits, proceedings, guarantees and indemnifications cannot be ascertained, and liabilities in indeterminate amounts may be imposed on us. It is possible that future results of operations or cash flows for any particular quarterly or annual period could be materially affected by an unfavorable resolution of these matters.

Our businesses are subject to extensive governmental regulation, which could reduce our profitability, limit our growth, or subject us to legal and regulatory actions.

Our businesses are subject to extensive legal and regulatory oversight throughout the world, including the Irish Companies Act, the U.S. securities laws, rules, and regulations, the rules and regulations promulgated by the FCA and a variety of other laws, rules, and regulations addressing, among other things, licensing, data privacy and protection, trade sanctions laws, restrictions and export controls, anti-money laundering, wage-and-hour standards, employment and labor relations, anti-competition, anti-corruption, currency, reserves, government contracting, and the amount of local investment with respect to our operations in certain countries. This legal and regulatory oversight could reduce our profitability or limit our growth by: increasing the costs of legal and regulatory compliance; limiting or restricting the products or services we sell, the markets we serve or enter, the methods by which we sell our products and services, the overall structure of our business units, the type of services and prices we can charge for our services, or the form of compensation we can accept from our clients, carriers, and third parties; or by subjecting our businesses to the possibility of legal and regulatory actions, proceedings, or fines.

The global nature of our operations increases the complexity and cost of compliance with laws and regulations adding to our cost of doing business. In addition, many of these laws and regulations may have differing or conflicting legal standards across jurisdictions, increasing the complexity and cost of compliance. In emerging markets and other jurisdictions with less developed legal systems, local laws and regulations may not be established with sufficiently clear and reliable guidance to provide us adequate assurance that we are operating our business in a compliant manner with all required licenses or that our rights are otherwise protected. In addition, certain laws and regulations, such as the Foreign Corrupt Practices Act and the Foreign Account Tax Compliance provisions of the Hiring Incentives to Restore Employment Act in the U.S., and the Bribery Act of 2010 in the U.K., impact our operations outside of the legislating country by imposing requirements for the conduct of overseas operations, and in several cases, requiring compliance by foreign subsidiaries.

In addition to the complexity of the laws and regulations themselves, the development of new laws and regulations or changes in application or interpretation of current laws and regulations or conflict between them also increases our legal and regulatory compliance complexity. Additionally, our acquisitions of new businesses and our continued operational changes and entry into new jurisdictions and new service offerings increases our legal and regulatory compliance complexity, as well as the type of governmental oversight to which we may be subject. Changes in laws and regulations could mandate significant and costly changes to the way we implement our services and solutions, impose additional licensure requirements or costs to our operations and services, or cause us to cease offering certain services or solutions. Furthermore, as we enter new jurisdictions or businesses and further develop and expand our services, including through acquisitions, we may become subject to additional types of laws and governmental oversight and supervision, such as those applicable to the financial lending or other service institutions. Regulatory developments that could result in changes that adversely affect us or cause us to change our business or operations include: additional requirements respecting data privacy, data security, and data usage in jurisdictions in which we operate that may increase our costs of compliance and potentially reduce the manner in which we can use data; changes in tax regulations in the jurisdictions in which we operate; regulatory actions or changes that require us to change our compensation model; or additional regulations promulgated by , regulatory bodies in jurisdictions in which we operate.

Governmental and public attention to climate change and environmental matters, including new or enhanced reporting, diligence or disclosure rules and regulations, could expand the nature, scope, and complexity of matters that we are required to control, assess, and report. These and other rapidly changing laws, rules and regulations, may increase the cost of our compliance and risk management and otherwise impact our business, which could have a material adverse effect on our business, results of operations, and financial condition. In addition, the shift toward a lower-carbon economy, driven by changes in laws, rules and regulations, low-carbon technology advancement, consumer sentiment, and/or liability risks, may negatively impact our business model and/or the business models of our clients. In addition, as governments, investors and other stakeholders face additional pressures to accelerate actions to address climate change and other ESG topics, governments and other stakeholders may impose new rules or expectations causing a shift in disclosure and other behaviors that may negatively impact our business.

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In all jurisdictions, the applicable laws and regulations are subject to amendment or interpretation by regulatory authorities. Generally, such authorities are vested with relatively broad discretion to grant, renew, and revoke licenses and approvals and to implement regulations. Accordingly, we may have a license revoked or be unable to obtain new licenses and therefore be precluded or suspended from carrying on or developing some or all of our activities or otherwise fined or penalized in a given jurisdiction. No assurances can be given that our business can further develop or continue to be conducted in any given jurisdiction in the future as it has been conducted in the past. Changes in the regulatory scheme, or even changes in how existing regulations are interpreted, could have an adverse impact on our results of operations by limiting revenue streams or increasing costs of compliance.

Our business’ regulatory oversight also includes licensing of insurance brokers and agents, managing general agency or general underwriting operations, and the regulation of the handling and investment of client funds held in a fiduciary capacity. Our continuing ability to provide insurance broking in the jurisdictions in which we operate depends on our compliance with the rules and regulations promulgated by the regulatory authorities in each of these jurisdictions, and our failure to adhere to these rules and regulations can expose us to fines or other sanctions. Also, we can be affected indirectly by the governmental regulation and supervision of insurance companies. For instance, if we are providing or managing general underwriting services for an insurer, we may have to contend with regulations affecting our client.

Services provided in our Health Solutions and Wealth Solutions businesses are also the subject of ever-evolving government regulation, either because the services provided to our clients are regulated directly or because third parties upon whom we rely to provide services to clients are regulated, thereby indirectly affecting the manner in which we provide services to those clients. In particular, our health care exchange business depends upon the private sector of the U.S. insurance system and its role in financing health care delivery, and insurance carriers’ use and payment of commissions to agents, brokers, and other organizations to market and sell individual and family health insurance products and plans. Uncertainty regarding, or any changes to, state or federal law, or the interpretation of such law by applicable regulatory agencies could delay client adoption of our health care exchanges, impair our ability to retain clients who have adopted our health care exchanges, or cause insurance carriers to alter or eliminate the products and plans that they offer or attempt to move members into new products or plans for which we receive lower commissions. In addition, changes in laws, government regulations, or the way those regulations are interpreted in the jurisdictions in which we operate could affect the viability, value, use, or delivery of benefits and human resources programs, including changes in regulations relating to health and welfare plans (such as medical), defined contribution plans (such as 401(k)), or defined benefit plans (such as pension), may adversely affect the demand for, or profitability of, our services.

If we violate the laws and regulations to which we are subject, we could be subject to fines, penalties, or criminal sanctions and could be prohibited from conducting business in one or more countries. There can be no assurance that our employees, contractors, or agents will not violate these laws and regulations, causing an adverse effect on our operations and financial condition.

Heightened regulatory oversight and scrutiny may lead to additional regulatory investigations, increased government involvement, or enforcement actions, which could consume significant management time and resources and could have adverse effects on our business and operations. For instance, increased scrutiny by competition authorities may increase our costs of doing business or force us to change the way we conduct business or refrain from or otherwise alter the way we engage in certain activities. Additionally, we could suffer significant financial or reputational harm if we fail to properly identify and manage potential conflicts of interest, which exist or could exist any time we or any of our employees have or may have an interest in a transaction or engagement that is inconsistent with our clients’ interests. This could occur, for example, when we are providing services to multiple parties in connection with a transaction. We also provide services to advise and assist in satisfying all our clients’ needs from all our businesses, creating a greater potential for conflicts with advisory services.

Due to the broad scope of our businesses and our client base, we regularly address potential conflicts of interest, including, without limitation, situations where our services to a particular client or our own investments or other interests conflict, or are perceived to conflict, with the interests of another client. If these are not adequately identified and managed, this could then lead to failure or perceived failure to protect the client’s interests, with consequential regulatory and reputational risks, including litigation or enforcement actions that could adversely affect us and our operations. Identifying conflicts of interest may also prove particularly difficult as we continue to bring systems and information together and integrate newly acquired businesses. In addition, we may not be able to adequately address such conflicts of interest.

Insurance intermediaries have traditionally been remunerated by base commissions paid by insurance carriers in respect of insurance placements for clients, or by fees paid by clients. Intermediaries also obtain other revenue from insurance carriers. This revenue, when derived from carriers in their capacity as insurance markets (as opposed to as corporate clients of the intermediaries where they may be purchasing insurance or reinsurance or other non-market related services), is commonly known as MDI. MDI is another example of an area in which potential conflicts of interest may arise. This revenue may be subject to scrutiny by various regulators under conflict of interest, anti-trust, unfair competition, conduct and anti-bribery laws

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and regulations. MDI takes a variety of forms, including volume- or profit-based contingent commissions, facilities administration charges, business development agreements, and fees for providing consulting services to carriers. While accepting MDI is a lawful and acceptable business practice, we cannot predict whether our position will result in regulatory or other scrutiny and our controls may not be fully effective.

Failure to protect our intellectual property rights, or allegations that we have infringed on the intellectual property rights of others, could harm our reputation, ability to compete effectively, and financial condition.

To protect our intellectual property rights, we rely on a combination of trademark laws, copyright laws, patent laws, trade secret protection, confidentiality agreements, and other contractual arrangements with our affiliates, employees, clients, strategic partners, and others, as well as internal policies and procedures regarding our management of intellectual property. However, the protective steps that we take may be inadequate to deter misappropriation of our proprietary information. In addition, we may be unable to detect the unauthorized use of, or take appropriate steps to enforce, our intellectual property rights. Further, we operate in many jurisdictions and effective trademark, copyright, patent, and trade secret protection may not be available or adequate in every country or jurisdiction in which we offer our services or employ our colleagues. Additionally, our competitors may develop products similar to our products that do not conflict with our related intellectual property rights. Failure to protect our intellectual property adequately could harm our reputation and affect our ability to compete effectively.

In addition, to protect or enforce our intellectual property rights, we may initiate litigation against third parties, such as infringement suits or interference proceedings. Third parties may assert intellectual property rights claims against us, which may be costly to defend, could require the payment of damages, and could limit our ability to use or offer certain technologies, products, or other intellectual property. Any intellectual property claims, with or without merit, could be expensive, take significant time and divert management’s attention from other business concerns. Successful challenges against us could require us to modify or discontinue our use of technology or business processes where such use is found to infringe or violate the rights of others, or require us to purchase licenses from third parties, any of which could adversely affect our business, financial condition, and operating results.

Operational Risks

Our results of operations have been adversely affected and could be materially adversely affected in the future by the COVID-19 global pandemic.

The COVID-19 global pandemic and the emergence of COVID-19 variants has created significant public health concerns and significant volatility, uncertainty, and economic disruption in every region where we operate.

A number of evolving factors related to the global pandemic and the post-pandemic recovery period may influence the duration, nature and extent of the impact on our business and financial results. Such factors include worldwide macroeconomic conditions, including interest rates, employment rates, consumer confidence and spending, gross domestic product, property values, and changes in client behavior, and foreign exchange rates in each of the markets in which we operate; business closures; changes in laws, regulations (including those changes that may provide for extended premium payment terms), and guidance; court decisions and litigation trends; a decline in business and the ability of counterparties to pay for our services on time or at all; an increased number of E&O claims in those areas impacted by the pandemic, as well as an increase in the incidence or severity of E&O claims against us and our market partners; our ability to sell and provide our services, including due to the impact of travel restrictions, lockdowns, quarantines, social distancing, and alternative work arrangements; the health of, and the effect of the pandemic on, our employees; political disruption; potential effects on our internal controls and risk mitigation processes, including those over financial reporting, as a result of changes in working environments for our employees and business partners; resurgences of spread; identification of new, more contagious variants of the virus; resulting “lockdowns,” government restrictions, mandates, requirements or recommendations; and uncertainties in vaccine adoption.

In addition, the continuing COVID-19 pandemic may again create significant disruptions or volatility in the credit or financial markets, or impact our credit ratings, which could adversely affect our ability to access capital on favorable terms or at all.

Finally, the impact of the COVID-19 pandemic may heighten other risks discussed in this Annual Report on Form 10-K, which could adversely affect our business, financial condition, results of operations, cash flows, and stock price.

The economic and political conditions of the countries and regions in which we operate could have an adverse impact on our business, financial condition, operating results, liquidity, and prospects for growth.

Our operations in countries undergoing political change or experiencing economic instability are subject to uncertainty and risks that could materially adversely affect our business. These risks include, particularly in emerging markets, the possibility

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we would be subject to undeveloped or evolving legal systems, unstable governments and economies, and potential governmental actions affecting the flow of goods, services, and currency.

Furthermore, the U.K. formally withdrew from the E.U., commonly referred to as Brexit. The E.U. and U.K. ratified a trade cooperation agreement governing their future relationship in 2021 to address trade, economic arrangements, law enforcement, judicial cooperation and a governance framework including procedures for dispute resolution, among other things. Because the agreement merely sets forth a framework in many respects and requires ongoing complex additional bilateral negotiations between the U.K. and the E.U. as both parties continue to work on the rules for implementation, significant political and economic uncertainty remains. We have significant operations and a substantial workforce within the U.K., and we previously enjoyed certain benefits based on the U.K.’s membership in the E.U., and the lack of clarity around the future relationship between the U.K. and the E.U. creates uncertainty that may have a material impact on our business and operations. We may also be required to incur additional expense as we adapt to and create the ability to operate within the new political and regulatory environment.

Additionally, any development that has the effect of devaluing the euro or British pound could meaningfully reduce the value of our assets and reduce the usefulness of liquidity alternatives denominated in that currency such as our multicurrency U.S. credit facility. We also deposit some of our cash, including cash held in a fiduciary capacity, with certain European financial institutions. While we continuously monitor and manage exposures associated with those deposits, to the extent the uncertainty surrounding economic stability in Europe and the future viability of the euro suddenly and adversely impacts those financial institutions, some or all of those cash deposits could be at risk.

Our success depends on our ability to retain, attract and develop experienced and qualified personnel, including our senior management team and other personnel.

We depend, in material part, upon the members of our senior management team who possess extensive knowledge and a deep understanding of our business and our strategy, as well as the colleagues who are critical to developing and retaining client relationships. The unexpected loss of services of any of these senior leaders could have a disruptive effect adversely impacting our ability to manage our business effectively and execute our business strategy. Additionally, competition for experienced professional personnel is increasingly intense, and we are constantly working to retain, attract and develop these professionals. If we cannot successfully do so, our business, operating results, and financial condition could be adversely affected. We may also become involved in disputes and litigation in connection with our efforts to retain and hire personnel, which can be disruptive to our business. While we have plans for key management succession and long-term compensation plans designed to retain our senior management team and critical colleagues, if our succession plans and retention programs do not operate effectively, our business could be adversely affected.

We strive to maintain an equitable work environment that unlocks the full potential of all of our personnel - this includes our commitment to diversity and inclusion, focus on colleague wellness and mental health, and building a flexible work environment that meets colleague and client needs. If we are unsuccessful in maintaining such a work environment or adapting to colleague needs or expectations, we could experience difficulty attracting and retaining personnel, which could have a negative impact on our business.

Our global operations expose us to various international risks that could adversely affect our business.

Our operations are conducted globally. Accordingly, we are subject to regulatory, legal, economic, and market risks associated with global operations and sourcing, including:

•difficulties in staffing and managing our offices, and overseeing joint venture operations and compliance in disparate jurisdictions, including due to unexpected inflation (including wage inflation) or job turnover, and the increased travel, infrastructure, and legal and compliance costs and risks associated with multiple international locations;

•hyperinflation in certain countries;

•conflicting regulations across the countries in which we do business;

•imposition of investment requirements or other restrictions by governments in certain countries;

•longer payment cycles;

•greater difficulties in collecting accounts receivable;

•insufficient demand for our services in certain jurisdictions;

•our ability to execute effective and efficient cross-border sourcing of services on behalf of our clients;

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•the reliance on or use of third parties to perform services on behalf of the Company;

•disparate tax regimes;

•restrictions on the import and export of technologies; and

•trade barriers.

The occurrence of natural or man-made disasters could result in declines in business and increases in claims that could adversely affect our financial condition and results of operations.

We are exposed to various risks arising out of natural disasters, including earthquakes, hurricanes, fires, floods, tornadoes, extreme weather, or other climate events; pandemic health events, and man-made disasters, including acts of terrorism, civil unrest, violence, military actions, and cyber-terrorism (including, but not limited to, ransomware). The continued threat of terrorism and other events or disasters may cause significant volatility in global financial markets, and a natural or man-made disaster could trigger energy shortages, public health issues, or an economic downturn or instability in the areas directly or indirectly affected by the disaster. These consequences could, among other things, result in a decline in business and increased claims from those areas. They could also result in reduced underwriting capacity, making it more difficult for our professionals to place business. Disasters also could disrupt public and private infrastructure, including communications and financial services, which could disrupt our normal business operations. If access to underwriting markets for certain lines of coverage becomes unavailable or difficult due to the impact of climate change on the claims environment, this may have a negative impact on our clients’ access to coverage, which could in turn reduce our ability to place certain lines of coverage and negatively impact our business.

A natural or man-made disaster also could disrupt the operations of our counterparties or result in increased prices for the products and services they provide to us. In addition, a disaster could adversely affect the value of the assets in our investment portfolio. Finally, a natural or man-made disaster could increase the incidence or severity of E&O claims against us. Climate change may increase the likelihood or severity of a natural or man-made disaster.

Our inability to successfully recover should we experience a disaster or other business continuity problem could cause material financial loss, loss of human capital, regulatory actions, reputational harm, or legal liability.

Our operations are dependent upon our ability to protect our personnel, offices, and technology infrastructure against damage from business continuity events that could have a significant disruptive effect on our operations. Should we experience a local or regional disaster or other business continuity problem, such as a security incident or attack, a natural disaster, climate event, terrorist attack, pandemic, power loss, telecommunications failure, or other natural or man-made disaster, our continued success will depend, in part, on the availability of our personnel and office facilities, and the proper functioning of computer systems, telecommunications, and other related systems and operations. In events like these, while our operational size, the multiple locations from which we operate, and our existing back-up systems provide us with some degree of flexibility, we still can experience near-term operational challenges in particular areas of our operations. We could potentially lose access to key executives, personnel, or client data or experience material adverse interruptions to our operations or delivery of services to our clients in a disaster recovery scenario. A disaster on a significant scale or affecting certain of our key operating areas within or across regions, or our inability to successfully recover should we experience a disaster or other business continuity problem, could materially interrupt our business operations and cause material financial loss, loss of human capital, regulatory actions, reputational harm, damaged client relationships, or legal liability.

We rely on third parties to perform key functions of our business operations enabling our provision of services to our clients. These third parties may act in ways that could harm our business.

We rely on third parties, and in some cases subcontractors, to provide services, data, and information such as technology, information security, funds transfers, data processing, support functions, and administration that are critical to the operations of our business. These third parties include correspondents, agents and other brokerage and intermediaries, insurance markets, data providers, plan trustees, payroll service providers, benefits administrators, software and system vendors, business process outsourcing providers, health plan providers, investment managers, and providers of human resources, among others. As we do not fully control the actions of these third parties, we are subject to the risk that their decisions, actions, or inactions may adversely impact us and replacing these service providers could create significant delay and expense. A failure by third parties to comply with service level agreements or regulatory or legal requirements in a high quality and timely manner, particularly during periods of our peak demand for their services, could result in economic and reputational harm to us. In addition, we face risks as we transition from in-house functions to third- party support functions and providers that there may be disruptions in service or other unintended results that may adversely affect our business operations. These third parties face their own technology, operating, business, and economic risks, and any significant failures by them, including the improper use or disclosure of our confidential client, employee, or company information, could cause harm to our business and reputation. An

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interruption in or the cessation of service by any service provider as a result of systems failures, cybersecurity incidents (including, but not limited to, ransomware), capacity constraints, financial difficulties, or for any other reason could disrupt our operations, impact our ability to offer certain products and services, and result in contractual or regulatory penalties, liability claims from clients, or employees, damage to our reputation, and harm to our business.

Our business is exposed to risks associated with the handling of client funds.

Certain of our businesses collect premiums from insureds and remits the premiums to the respective insurers. We also collect claims or refunds from insurers on behalf of insureds, which are then remitted to the insureds. Consequently, at any given time, we may be holding and managing funds of our clients. This function creates a risk of loss arising from, among other things, fraud by employees or third parties, execution of unauthorized transactions, errors relating to transaction processing, or other cybersecurity events or security breaches. We are also potentially at risk in the event the financial institution in which we hold these funds suffers any kind of insolvency or liquidity event. The occurrence of any of these types of events in connection with this function could cause us financial loss and reputational harm.

In connection with the implementation of our corporate strategies and initiatives, we face risks associated with, among others, the acquisition or disposition of businesses, the integration and development of acquired businesses, and the entry into new lines of business or products.

In pursuing our corporate strategy, we often acquire other businesses or dispose of or exit businesses we currently own and we routinely are actively engaged in the process of identifying, analyzing, and negotiating possible transactions. The success of this strategy is dependent upon our ability to identify appropriate acquisition and disposition targets, negotiate transactions on favorable terms, secure regulatory approval of transactions where required, complete transactions and, in the case of acquisitions, successfully integrate them into our existing businesses and culture. If a proposed transaction is not consummated, the time and resources spent pursuing it could adversely impact employees, clients and shareholders and the failure to consummate a proposed transaction could result in payment of termination fees and reimbursement of expenses, reputational harm, disputes and litigation and missed opportunities to locate and acquire other businesses. If acquisitions are made, there can be no assurance that we will realize the anticipated benefits of such acquisitions, including, but not limited to, revenue growth, operational efficiencies, or expected synergies, and we could incur unexpected costs in connection with integration. If we dispose of or otherwise exit certain businesses, there can be no assurance that we will not incur certain disposition related charges, will not be subject to post-closing liabilities, obligations or restrictions, will be able to reduce overhead related to the divested assets, or will realize the intended benefits of the disposition.

We may enter new lines of business or offer new products and services within existing lines of business either through acquisitions or through initiatives to generate organic revenue growth. These new lines of business, products, and services present the Company with additional risks, particularly in instances where the markets are new or not fully developed. Such risks include the investment of significant time and resources; the possibility that these efforts will be not be successful; the possibility that the marketplace does not accept our products or services or that we are unable to retain clients that adopt our new products or services; and the risk of new or additional liabilities associated with these efforts. In addition, many of the businesses that we acquire and develop will likely have significantly smaller scales of operations prior to the implementation of our growth strategy. If we are not able to manage the growing complexity of these businesses, including improving, refining, or revising our systems and operational practices, and enlarging the scale and scope of the businesses, our business may be adversely affected. Other risks include developing knowledge of and experience in the new business, product or service, integrating the acquired business into our systems and culture, recruiting and retaining experienced professionals, and developing and capitalizing on new relationships with experienced market participants. External factors, such as compliance with new or revised regulations, competitive alternatives, and shifting market preferences may also impact the successful implementation of a new line of business, products, or services. Failure to manage these risks in the acquisition or development of new businesses could materially and adversely affect our business, results of operations, and financial condition.

We are subject to various risks and uncertainties in connection with the sale of the Divested Business.

On May 1, 2017, the Company completed the sale of the benefits administration and business process outsourcing business (the “Divested Business) to an entity controlled by affiliates of The Blackstone Group L.P. (the “Buyer”). This transaction carries inherent risks, including the risk that we will not earn the $500 million of additional consideration or otherwise realize the intended value of the transaction.

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Risks Related to Technology, Cybersecurity, and Data Protection

We rely on complex information technology systems and networks to operate our business. Any significant system or network disruption due to a breach in the security of our information technology systems could have a negative impact on our reputation, operations, sales, and operating results.

We rely on the efficient, uninterrupted, and secure operation of complex information technology systems and networks, some of which are within the Company and some of which are outsourced to third parties. All information technology systems are potentially vulnerable to damage or interruption from a variety of sources, including but not limited to cyber-attacks, computer viruses, security breaches, and unauthorized access or improper actions by insiders or employees. We are at risk of attack by a growing list of adversaries through new and increasingly sophisticated methods of attack, including methods that take advantage of remote work scenarios due to COVID-19. Because the techniques used to obtain unauthorized access or sabotage systems change frequently, we may be unable to anticipate these techniques, implement adequate preventative measures, or detect and respond quickly enough in the event of an incident or attack. We regularly experience social engineering attempts, attacks to our systems and networks and have from time to time experienced cybersecurity incidents, such as computer viruses, unauthorized parties gaining access to our information technology systems, ransomware incidents, data loss via malicious and non-malicious methods, and similar incidents, which to date have not had a material impact on our business. If we are unable to efficiently and effectively maintain and upgrade our system safeguards, we may incur unexpected costs and certain of our systems may become more vulnerable to unauthorized access. Problems with the information technology systems of vendors, including breakdowns or other disruptions in communication services provided by a vendor, failure of a vendor to handle current or higher volumes, difficulties in the migration of services or data to third parties or the cloud hosted by third parties, cyber-attacks, and security breaches could adversely affect our ability to deliver products and services to customers and otherwise conduct business. Additionally, we are a global and acquisitive organization and we therefore might not adequately identify weaknesses in certain of our information systems, including those of targets we acquire, which could expose us to unexpected liabilities and fines or make our own systems more vulnerable to attack. These types of incidents affecting us, our clients, insurance carriers, vendors, or other third-parties could result in intellectual property or other confidential information being lost or stolen, including client or employee personal information or company data.

We have implemented various measures to manage our risks related to system and network security and disruptions, but a security breach or a significant or extended disruption in the functioning of our information technology systems could damage our reputation, cause us to lose clients, adversely impact our operations, sales, and operating results, and require us to incur significant expense and divert resources to address and remediate or otherwise resolve such issues. Additionally, in order to maintain the level of security, service, and reliability that our clients require, we may be required to make significant additional investments in our information technology system.

Improper disclosure of confidential, personal, or proprietary data could result in regulatory scrutiny, legal liability, or harm to our reputation.

One of our significant responsibilities is to maintain the security and privacy of our employees’ and clients’ confidential and proprietary information, including confidential information about our clients’ and employees’ compensation, medical information, and other personally identifiable information. We maintain policies, procedures, and technological safeguards designed to protect the security and privacy of this information. Nonetheless, we cannot eliminate the risk of human error, employee or vendor malfeasance, or cyber-attacks that could result in improper access to or disclosure of confidential, personal, or proprietary information. Such access or disclosure could harm our reputation and subject us to liability under our contracts and laws and regulations that protect personal data, resulting in increased costs, fines, loss of revenue, and loss of clients. The release of confidential information as a result of a security breach could also lead to litigation or other proceedings against us by affected individuals or business partners, or by regulators, and the outcome of such proceedings, which could include penalties or fines, could have a significant negative impact on our business.

In many jurisdictions, including in the E.U. and the U.S., we are subject to laws and regulations relating to the collection, use, retention, security, and transfer of this information. These laws and regulations are frequently changing and are becoming increasingly complex and sometimes conflict among the various jurisdictions and countries in which we provide services both in terms of substance and in terms of enforceability. This makes compliance challenging and expensive. Additionally, certain jurisdictions’ regulations include notice provisions that may require us to inform affected clients or employees in the event of a breach of confidential information before we fully understand or appreciate the extent of the breach. These notice provisions present operational challenges and related risk. In particular, in 2021 there have been a number of new privacy laws around the globe including China, Brazil and significant privacy rulings in the E.U. relating to the “Schrems II” case, which imposed significant changes to the way companies export personal data from the E.U. We have had to implement new requirements set out in these laws within our business before the effective date causing distraction from other aspects of our business. This new guidance issued to firms by the European Regulators has and will continue to require significant time to implement and may require significant effort to review and effect applicable changes to IT systems and transfer methods. Non-compliance with new

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and existing laws could result in proceedings against us by governmental entities or others and additional costs in connection therewith. We expect additional jurisdictions to continue to adopt new privacy regulations and there to be amendments to existing regulations as governments continue to legislate in respect of personal data. We have and will continue to incur expenses and devote resources to bring our practices into compliance with these regulations and future regulations. Our failure to comply with or successfully implement processes in response to changing regulatory requirements in this area could result in legal liability, result in proceedings or fines against us by governmental entities or others, or impair our reputation in the marketplace. Further, regulatory initiatives in the area of data protection are more frequently including provisions allowing authorities to impose substantial fines and penalties, and therefore, failure to comply could also have a significant financial impact.

Our business performance and growth plans could be negatively affected if we are not able to develop, implement, update, and enhance technology-based solutions to support our business operations or if we are not able to effectively drive value for our clients through innovation and technology-based solutions.

Our success depends, in part, on our ability to enhance and implement the technology systems necessary to operate our businesses and to achieve intended efficiencies and improvements. We may not be successful in anticipating or responding to rapid and continuing changes in technology, industry standards and client preferences. The effort to gain technological expertise, develop new technologies in our business, and achieve internal efficiencies through technology require us to incur significant expenses.

We also make investments in technology-based solutions, including data and analytics solutions, for our clients. If we cannot innovate as quickly as our competitors, if our competitors develop more cost-effective technologies, or if our ideas are not accepted in the marketplace, it could have a material adverse effect on our ability to obtain and complete client engagements. For example, we have invested significantly in the development of our proprietary data and analytics tools including repositories of global insurance and reinsurance placement information, which we use to drive results for our clients in the insurance and reinsurance placement process. Our competitors are developing competing data and analytics tools, and their success in this space may impact our ability to differentiate our services to our clients through the use of unique technological solutions. Innovations in software, cloud computing, data and analytics or other technologies that alter how our services are delivered could significantly undermine our investment in the business if we are slow to innovate or unable to take advantage of these developments.

Risks Related to Being an Irish-incorporated Company

We are incorporated in Ireland, and Irish law differs from the laws in effect in the U.S. and may afford less protection to holders of our securities.

It may not be possible to enforce court judgments obtained in the U.S. against us in Ireland, based on the civil liability provisions of the U.S. federal or state securities laws. In addition, there is some uncertainty as to whether the courts of Ireland would recognize or enforce judgments of U.S. courts obtained against us or our directors or officers based on the civil liabilities provisions of the U.S. federal or state securities laws or hear actions against us or those persons based on those laws. We have been advised that the U.S. currently does not have a treaty with Ireland providing for the reciprocal recognition and enforcement of judgments in civil and commercial matters. Therefore, a final judgment for the payment of money rendered by any U.S. federal or state court based on civil liability, whether or not based solely on U.S. federal or state securities laws, would not automatically be enforceable in Ireland.

As an Irish company, we are governed by the Irish Companies Act, which differs in some material respects from laws generally applicable to U.S. corporations and shareholders, including, among others, differences relating to interested director and officer transactions and shareholder lawsuits. Likewise, the duties of directors and officers of an Irish company generally are owed to the company only. Shareholders of Irish companies generally do not have a personal right of action against directors or officers of the company and may exercise such rights of action on behalf of the company only in limited circumstances. Accordingly, holders of our securities may have more difficulty protecting their interests than would holders of securities of a corporation incorporated in a jurisdiction of the U.S.

In addition, depending on the circumstances, the acquisition, ownership and/or disposition of our ordinary shares may subject shareholders to different or additional tax consequences under Irish law including, but not limited to, Irish stamp duty, dividend withholding tax and capital acquisitions tax.

As an Irish public limited company, certain capital structure decisions regarding the Company will require the approval of shareholders, which may limit the Company’s flexibility to manage its capital structure.

Irish law generally provides that a board of directors may allot and issue shares (or rights to subscribe for or convert into shares) if authorized to do so by a company’s constitution or by an ordinary resolution of shareholders. Such authorization may

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be granted in respect of up to the entirety of a company’s authorized but unissued share capital and for a maximum period of five years, at which point it must be renewed by another ordinary resolution. The Company’s constitution authorizes our directors to allot shares up to the maximum of the Company’s authorized but unissued share capital for a period of five years from March 31, 2020. This authorization will need to be renewed by ordinary resolution upon its expiration and at periodic intervals thereafter. Under Irish law, an allotment authority may be given for up to five years at each renewal, but governance considerations may result in renewals for shorter periods or in respect of less than the maximum permitted number of shares being sought or approved.

Irish law also generally provides shareholders with statutory pre-emption rights when new shares are issued for cash. However, it is possible for such statutory pre-emption rights to be dis-applied in a company’s constitution or by a special resolution of shareholders. Such dis-application of pre-emption rights may be given in respect of up to the entirety of a company’s authorized but unissued share capital and for a maximum period of five years, at which point it must be renewed by another special resolution. The Company’s constitution dis-applies statutory pre-emption rights up to the maximum of the Company’s authorized but unissued share capital for a period of five years from March 31, 2020. This dis-application will need to be renewed by special resolution upon its expiration and at periodic intervals thereafter. Under Irish law, a dis-application of statutory pre-emption rights may be given for up to five years at each renewal, but governance considerations may result in renewals for shorter periods or in respect of less than the maximum permitted number of unissued shares being sought or approved.

Irish law requires us to have available “distributable profits” to pay dividends to shareholder and generally to make share repurchases and redemptions.

Under Irish law, we may only pay dividends and, generally, make share repurchases and redemptions from distributable profits. Distributable profits may be created through the earnings of the Company or other methods (including certain intra-group reorganizations involving the capitalization of the Company’s un-distributable profits and their subsequent reduction). While it is our intention to maintain a sufficient level of distributable profits in order to pay dividends on our ordinary shares and make share repurchases, there is no assurance that the Company will maintain the necessary level of distributable profits to do so.

Item 1B.    Unresolved Staff Comments

None.

Item 2.    Properties

We have offices in various locations throughout the world. Substantially all of our offices are located in leased premises. We maintain our corporate headquarters at Metropolitan Building, James Joyce Street, Dublin 1, Ireland, where we occupy approximately 43,000 square feet of space under an operating lease agreement that expires in 2032. The following are additional significant leased properties, along with the occupied square footage and expiration.

Property:	Occupied Square Footage	Lease Expiration Dates
200 E. Randolph Street, Chicago, Illinois	312,000	2028
165 Broadway, New York, New York	217,000	2028
122 Leadenhall Street, London, England	178,000	2034
4 Overlook Point, Lincolnshire, Illinois	174,000	2024

As leases expire, we do not anticipate difficulty in negotiating renewals or finding other satisfactory space if the premise becomes unavailable. We believe that the facilities we currently occupy are adequate for the purposes for which they are being used and are well maintained. In certain circumstances, we may have unused space and may seek to sublet such space to third parties, depending upon the demands for office space in the locations involved. Due to COVID-19, the vast majority of colleagues are working remotely. We continue to be fully operational and to reoccupy certain offices in phases, where deemed appropriate and in compliance with governmental restrictions considering the impact on health and safety of our colleagues, their families, and our clients, and we have restricted or minimized access to offices where appropriate to support the health and safety of our colleagues. See Note 8 “Lease Commitments” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report for information with respect to our lease commitments as of December 31, 2021.

Item 3.    Legal Proceedings

We hereby incorporate by reference Note 15 “Claims, Lawsuits, and Other Contingencies” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report.

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Item 4.    Mine Safety Disclosure

Not applicable.

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Information about our Executive Officers

The executive officers of Aon, as of February 18, 2022 unless otherwise noted, their business experience during a period of the last five years or longer, and their ages and positions held are set forth below.

Name	Age	Position
Eric Andersen	57	President. Mr. Andersen joined Aon in 1997 upon the completion of the acquisition of Minet. Mr. Andersen has served in a variety of roles during his more than 20 year career at Aon, including as Chief Executive Officer of Aon Risk Solutions Americas from 2011 to 2013, and Chief Executive Officer of Aon Benfield from September 2013 to May 2018. Mr. Andersen was appointed Co-President of the Company in May 2018 and became President in February 2020. He was named an Executive Officer in February 2017.
Gregory C. Case	59	Chief Executive Officer. Mr. Case became Chief Executive Officer of Aon in April 2005. He also served as Aon’s President from April 2005 to May 2018. Prior to joining Aon, Mr. Case was a partner with McKinsey & Company, a global management consulting firm, for 17 years, most recently serving as head of the Financial Services Practice. He previously was responsible for McKinsey’s Global Insurance Practice and was a member of McKinsey’s governing Shareholders’ Committee. Prior to joining McKinsey, Mr. Case worked for the investment banking firm of Piper, Jaffray and Hopwood and the Federal Reserve Bank of Kansas City.
Christa Davies	50	Chief Financial Officer. Ms. Davies became Executive Vice President - Global Finance in November 2007. In March 2008, Ms. Davies assumed the additional role of Chief Financial Officer. Prior to joining Aon, Ms. Davies served for 5 years in various capacities at Microsoft Corporation, an international software company, most recently serving as Chief Financial Officer of the Platform and Services Division. Before joining Microsoft in 2002, Ms. Davies served at ninemsn, an Australian joint venture with Microsoft.
Michael Neller	43	Chief Accounting Officer and Global Controller. Mr. Neller joined Aon in August 2011 as its Vice President, Technical Accounting and Policy. From December 2011 to February 2018, Mr. Neller served as Aon’s Deputy Global Controller. In this role, he was responsible for Aon’s Latin America and North America regions, as well as global accounting policy, corporate accounting, and external reporting. Before joining Aon, Mr. Neller served from July 2009 to August 2011 as a Senior Manager of KPMG LLP, an international public accounting firm, in its Department of Professional Practice (National Office). He was named Senior Vice President and Global Controller in February 2018.
James Platt	50	Chief Operating Officer. Mr. Platt joined Aon in September 2014 as the Chief Executive Officer of Aon Inpoint and Head of Data & Analytics for Aon Risk Solutions and served in that role until December 2016. From January 2017 through June 2019, Mr. Platt served as the Chief Operating Officer of Aon Risk Solutions, and then from June 2019 through September 2020, as the Company’s Global Solution Lines Chief Operating Officer. From September 2020 to June 2021, Mr. Platt served as Aon’s Business Chief Operating Officer and was appointed Chief Operating Officer of the Company in June 2021.
Jillian Slyfield	49	Chief Innovation Officer. Ms. Slyfield joined Aon in November 2015 as an Account Executive and later served as the Resident Sales Director for San Francisco until her appointment to Managing Director, Digital Economy Practice Leader in 2018. Ms. Slyfield was appointed Chief Innovation Officer of Aon in December 2021. Prior to joining Aon in 2015, Ms. Slyfield held client executive and commercial insurance executive positions at Marsh and Wells Fargo Insurance Services.
Lisa Stevens	52	Chief People Officer and Head of Global Human Capital Solutions. Ms. Stevens joined Aon in December 2018 as Global Executive Vice President and was named as Chief People Officer in October 2019. Prior to joining Aon, Ms. Stevens held a variety of roles during her 29-year career at Wells Fargo, most recently as Executive Vice President where she led the Western Region for the Community Bank.
Andy Weitz	45	Chief Marketing Officer. Mr. Weitz joined Aon in 2014 as Senior Vice President for Global Marketing and Communications. Before joining Aon, Mr. Weitz was President and CEO of the U.S. region for Hill + Knowlton Strategies, a global strategic communications consultancy. Prior to Hill + Knowlton, Mr. Weitz worked at Marsh, Inc., a global insurance brokerage, and served in various roles at Trilogy, Inc. a software company.
Darren Zeidel	50	General Counsel and Company Secretary. Mr. Zeidel was named General Counsel and Company Secretary in July 2019. Prior to this Mr. Zeidel held several leadership roles with Aon, including as Deputy General Counsel immediately prior to his appointment; Global Chief Counsel - Corporate, Retirement & Investment and Health Exchanges from 2017 to 2019; and Global Chief Counsel of Aon Hewitt upon joining Aon in 2012 to 2017. Before this Mr. Zeidel worked for Honeywell, where he held business segment general counsel roles in the aerospace strategic business unit and at Honeywell UOP LLC. Mr. Zeidel began his career as an Associate in the Mergers and Acquisitions group in the New York office of Skadden, Arps, Slate, Meagher & Flom, LLP.

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PART II

Item 5.    Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

Our class A ordinary shares, $0.01 nominal value per share, are traded on the NYSE under the trading symbol AON.

On February 17, 2022, the last reported sale price of our ordinary shares as reported by the NYSE was $281.04 per share. We have approximately 403 holders of record of our class A ordinary shares as of February 17, 2022.

The following information relates to the repurchases of equity securities by Aon or any affiliated purchaser during any month within the fourth quarter of the fiscal year covered by this report:

Period	Total Number of Shares Purchased	Average Price Paid per Share (1)		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs (2)	Maximum Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs (1) (2)
10/1/21 – 10/31/21	1,305,162	$	305.71	1,305,162	$	3,321,244,884
11/1/21 – 11/30/21	4,004,487	$	298.47	4,004,487	$	2,126,024,122
12/1/21 – 12/31/21	1,372,594	$	295.62	1,372,594	$	1,720,253,713
	6,682,243	$	299.30	6,682,243	$	1,720,253,713

(1)Does not include commissions or other costs paid to repurchase shares.

(2)The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in authorized repurchases in February 2022 for a total of $27.5 billion in repurchase authorizations.

Information relating to the compensation plans under which equity securities of Aon are authorized for issuance is set forth under Part III, Item 12 “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” of this report and is incorporated herein by reference.

We did not make any unregistered sales of equity in 2021.

Item 6.    [Reserve]

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Item 7.    Management’s Discussion and Analysis of Financial Condition and Results of Operations

EXECUTIVE SUMMARY OF 2021 FINANCIAL RESULTS

Aon plc is a leading global professional services firm providing a broad range of risk, health, and wealth solutions. Through our experience, global reach, and comprehensive analytics, we are better able to help clients meet rapidly changing, increasingly complex, and interconnected challenges. We are committed to accelerating innovation to address unmet and evolving client needs, so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business. Management is focused on strengthening Aon and uniting the firm with one portfolio of capability enabled by data and analytics and one operating model to deliver additional insight, connectivity, and efficiency.

Financial Results

The following is a summary of our 2021 financial results:

•Revenue increased $1.1 billion, or 10%, to $12.2 billion in 2021 compared to 2020, reflecting 9% organic revenue growth and a 2% favorable impact from foreign currency translation, partially offset by a 1% unfavorable impact from divestitures, net of acquisitions.

•Operating expenses increased $1.8 billion, or 22%, to $10.1 billion in 2021 compared to 2020 due primarily to a $1.3 billion increase in charges related to terminating the combination with WTW and related costs, increased expenses associated with 9% organic revenue growth, and a $195 million unfavorable impact from translating prior year period results at current period foreign exchange rates (“foreign currency translation”), partially offset by a $72 million decrease in amortization related to certain tradenames that were fully amortized in the second quarter of 2020 and a $58 million decrease in expenses related to divestitures, net of acquisitions.

•Operating margin decreased to 17.1% in 2021 from 25.1% in 2020. The decrease was driven by an increase in operating expenses as listed above, partially offset by organic revenue growth of 9%.

•Due to the factors set forth above, Net income was $1.3 billion in 2021, a decrease of $0.7 billion, or 35%, from 2020.

•Diluted earnings per share decreased 34% to $5.55 per share during the twelve months of 2021 compared to $8.45 per share for the prior year period.

•Cash flows provided by operating activities was $2.2 billion in 2021, a decrease of $0.6 billion, or 22%, from $2.8 billion in 2020, primarily due to the $1 billion termination fee payment and additional payments related to terminating the combination with WTW, partially offset by strong revenue growth.

We focus on four key metrics not presented in accordance with U.S. GAAP that we communicate to shareholders: organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, and free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our Consolidated Financial Statements. The following is our measure of performance against these four metrics for 2021:

•Organic revenue growth, a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth,” was 9% in 2021, compared to 1% organic growth in the prior year.

•Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was 30.1% in 2021, compared to 28.5% in the prior year. The increase in adjusted operating margin primarily reflects 9% organic revenue growth and a favorable impact from foreign currency translation of $63 million.

•Adjusted diluted earnings per share, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was $12.00 per share in 2021, an increase of $2.19 per share, or 22%, from $9.81 per share in 2020. The increase in adjusted diluted earnings per share primarily reflects strong operational performance and effective capital management, highlighted by $3.5 billion of share repurchase during 2021, and a favorable impact from foreign currency translation.

•Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was $2.0 billion in 2021, a decrease of $597 million, or 23%, from $2.6 billion in 2020, reflecting a decrease in cash flows from operations, partially offset by a $4 million decrease in capital expenditures.

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BUSINESS OVERVIEW

In the third quarter of 2021, we announced a realignment of our principal service lines to the following: Commercial Risk Solutions, Reinsurance Solutions, Health Solutions, and Wealth Solutions. Realignment to these four solution lines results in the following changes in the presentation of our principal service line reporting:

•Data & Analytic Services’ revenue and organic revenue results, which were previously reported as a separate principal service line and include Affinity, Aon Inpoint, CoverWallet, and ReView, are included within Commercial Risk Solutions.

•Human Capital, which was previously reported within Retirement Solutions, is included within Health Solutions’ revenue and organic revenue results.

•Wealth Solutions includes revenue and organic revenue results for all businesses previously reported within Retirement Solutions, excluding Human Capital.

The changes in the solution line structure affects only the manner in which our revenue and organic revenue results for our principal service lines were previously reported and have no impact our previously reported Consolidated Financial Statements, results of operations, or total organic revenue growth. We continue to operate as one segment that includes all of our operations. See the “Principal Products and Services” section in Part I, Item 1 of this report for information on each of the four principal service lines.

TERMINATION OF BUSINESS COMBINATION AGREEMENT

On March 9, 2020, we and WTW entered into a Business Combination Agreement with respect to a combination of the parties (the “Combination”). The parties’ respective shareholders approved the Combination on August 26, 2020.

On June 16, 2021, the DOJ filed a civil antitrust lawsuit against the Company and WTW in the United States District Court for the District of Columbia seeking to enjoin the Combination. On July 26, 2021, the Company and WTW mutually agreed to terminate the Business Combination Agreement (the “Termination Agreement”). Pursuant to the Termination Agreement, the Business Combination Agreement was terminated and a termination fee of $1 billion (the “Termination Fee”) was paid to WTW. Following the termination, the lawsuit by the DOJ was dismissed.

Aon Corporation, a subsidiary of Aon plc, paid the Termination Fee to WTW on July 27, 2021, reflecting that U.S. business services provided by Aon Corporation and its subsidiaries were the primary focus of the DOJ’s challenge to our proposed combination. The Termination Fee was paid to defend the existing U.S. business of Aon Corporation and to avoid additional remedy divestitures of critical Aon Corporation business segments in the U.S. and the continuing delay and uncertainty in completing the combination.

COVID-19 PANDEMIC

The outbreak of the coronavirus, which causes COVID-19, was declared by the World Health Organization to be a pandemic and has impacted almost all countries, in varying degrees, creating significant public health concerns, and significant volatility, uncertainty, and economic disruption in every region in which we operate. The COVID-19 pandemic has resulted, and may continue to result, in significant economic disruption and volatility, although in recent months progress has been made in the development and distribution of vaccines, contributing to overall improved economic conditions globally, despite recent developments as a result of the Delta and Omicron variants. We continue to closely monitor the situation and its impacts on our business, liquidity, and capital planning initiatives. We continue to be fully operational and to reoccupy certain offices in phases, where deemed appropriate and in compliance with governmental restrictions considering the impact on health and safety of our colleagues, their families, and our clients, and we have restricted or minimized access to offices where appropriate to support the health and safety of our colleagues. We continue to deploy business continuity protocols to facilitate remote working capabilities to ensure the health and safety of our colleagues and to comply with public health and travel guidelines and restrictions.

As the situation continues to evolve, the scale and duration of disruption cannot be predicted, and it is not possible to quantify or estimate the full impact that COVID-19 will have on our business. While we continue to focus on managing our cash flow to meet liquidity needs, our results of operations, particularly with respect to our more discretionary revenues, may be adversely affected. However, for the year ended December 31, 2021, the impacts of COVID-19 on our business results have lessened and we have seen overall strength across the firm. We continue to monitor the situation closely.

The impacts of the pandemic on our business operations and results of operations for the year ended December 31, 2021 are further described in the sections entitled “Review of Consolidated Results” and “Liquidity and Financial Condition” contained in Part II, Item 7 of this report.

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ENVIRONMENTAL, SOCIAL, AND GOVERNANCE

For many companies, the management of ESG risks and opportunities has become increasingly important. Aon offers a wide range of consulting and advisory solutions designed to address and manage ESG issues for clients. We view ESG risks as presenting an important opportunity to help clients and improve our impact on ESG matters.

REVIEW OF CONSOLIDATED RESULTS

Summary of Results

Our consolidated results are as follow (in millions, except per share data):

	Years Ended December 31
	2021		2020		2019
Revenue
Total revenue	$	12,193	$	11,066	$	11,013
Expenses
Compensation and benefits	6,738		5,905		6,054
Information technology	477		444		494
Premises	327		291		339
Depreciation of fixed assets	179		167		172
Amortization and impairment of intangible assets	147		246		392
Other general expense	2,235		1,232		1,393
Total operating expenses	10,103		8,285		8,844
Operating income	2,090		2,781		2,169
Interest income	11		6		8
Interest expense	(322)		(334)		(307)
Other income	152		13		—
Income before income taxes	1,931		2,466		1,870
Income tax expense	623		448		297
Net income	1,308		2,018		1,573
Less: Net income attributable to noncontrolling interests	53		49		41
Net income attributable to Aon shareholders	$	1,255	$	1,969	$	1,532
Diluted net income per share attributable to Aon shareholders	$	5.55	$	8.45	$	6.37
Weighted average ordinary shares outstanding - diluted	226.1		233.1		240.6

Consolidated Results for 2021 Compared to 2020

Revenue

Total revenue increased $1.1 billion, or 10%, to $12.2 billion in 2021, compared to $11.1 billion in 2020. The increase was driven by 9% organic revenue growth and a 2% favorable impact from foreign currency translation, partially offset by a 1% unfavorable impact from divestitures, net of acquisitions.

Commercial Risk Solutions revenue increased $774 million, or 13%, to $6.6 billion in 2021, compared to $5.9 billion in 2020. Organic revenue growth was 11% in 2021, reflecting growth across every major geography, driven by strong new business generation, retention, and management of the renewal book portfolio. Strength in retail brokerage was highlighted by double-digit growth in the U.S., Latin America, and Asia. Results also reflect growth in the more discretionary portions of the business, including double-digit growth in transaction solutions and project-related work. On average globally, exposures and pricing were both modestly positive, which resulted in a modestly positive market impact overall.

Reinsurance Solutions revenue increased $183 million, or 10%, to $2.0 billion in 2021, compared to $1.8 billion in 2020. Organic revenue growth was 8% in 2021 driven by strong net new business generation in treaty, as well as solid growth in facultative placements and double-digit growth in capital markets transactions. In addition, market impact was modestly positive on results.

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Health Solutions revenue increased $87 million, or 4%, to $2.2 billion in 2021, compared to $2.1 billion in 2020. Organic revenue growth was 10% in 2021 driven by double-digit growth in human capital due to growth in both rewards and assessments solutions. In health and benefits brokerage, solid growth globally in the core was driven by strong retention and management of the renewal book portfolio, as well as growth in the more discretionary portions of the business, including double-digit growth in voluntary benefits and enrollment solutions and project-related work.

Wealth Solutions revenue increased $85 million, or 6%, to $1.4 billion in 2021, compared to $1.3 billion in 2020. Organic revenue growth was 2% in 2021 driven by growth in investments, including solid growth in delegated investment management, as well as growth in retirement, primarily from higher utilization rates and project-related work.

Compensation and Benefits

Compensation and benefits increased $833 million, or 14%, in 2021 compared to 2020. The increase was primarily driven by an increase in expense associated with 9% organic revenue growth, a $245 million increase in charges related to terminating the combination with WTW and related costs, and a $151 million unfavorable impact from foreign currency translation, partially offset by a $17 million decrease in expenses related to divestitures, net of acquisitions.

Information Technology

Information technology, which represents costs associated with supporting and maintaining our infrastructure, increased $33 million, or 7%, in 2021 compared to 2020. The increase was primarily driven by a $17 million increase in charges related to terminating the combination with WTW and related costs, an increase in expense associated with 9% organic revenue growth, investments in long-term growth, and a $5 million unfavorable impact from foreign currency translation.

Premises

Premises, which represents the cost of occupying offices in various locations throughout the world, increased $36 million, or 12%, in 2021 compared to 2020. The increase was primarily driven by a $22 million increase in charges related to terminating the combination with WTW and related costs and a $10 million unfavorable impact from foreign currency translation.

Depreciation of Fixed Assets

Depreciation of fixed assets primarily relates to software, leasehold improvements, furniture, fixtures and equipment, computer equipment, buildings, and automobiles. Depreciation of fixed assets increased $12 million, or 7%, in 2021 compared to 2020. The increase was primarily driven by a $16 million increase in charges related to terminating the combination with WTW and related costs.

Amortization and Impairment of Intangible Assets

Amortization and impairment of intangibles primarily relates to finite-lived tradenames and customer-related, contract-based, and technology assets. Amortization and impairment of intangibles decreased $99 million, or 40%, in 2021 compared to 2020. The decrease was primarily driven by a $72 million decrease from certain tradenames that were fully amortized in the second quarter of 2020.

Other General Expenses

Other general expenses increased $1.0 billion, or 81%, in 2021 compared to 2020. The increase was primarily driven by a $1.0 billion increase in charges related to terminating the combination with WTW and related costs, a $21 million unfavorable impact from foreign currency translation, and an increase in expense associated with 9% organic revenue growth, partially offset by a $37 million decrease in expenses related to divestitures, net of acquisitions.

Interest Income

Interest income represents income earned on operating cash balances and other income-producing investments. It does not include interest earned on Funds held on behalf of clients. Interest income was $11 million in 2021, an increase of $5 million, or 83%, from 2020.

Interest Expense

Interest expense, which represents the cost of our debt obligations, was $322 million in 2021, a decrease of $12 million, or 4%, from 2020. The decrease was primarily driven by lower average outstanding term debt.

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Other Income

Other income was $152 million in 2021, compared to $13 million in 2020. Other income in 2021 primarily includes $142 million of gains from the disposal of business, compared to $25 million in 2020.

Income before Income Taxes

Due to factors described above, income before income taxes was $1.9 billion in 2021, a 22% decrease from $2.5 billion in 2020. The decrease was primarily driven by a $1.0 billion increase in charges related to terminating the combination with WTW and related costs, as previously described.

Income Taxes

The effective tax rate on net income was 32.3% in 2021 and 18.2% in 2020. The primary drivers of the 2021 tax rate were the impact of the Termination Fee, the U.K. statutory tax rate increase, and the tax benefit of share-based payments. The U.K. enacted legislation in the second quarter of 2021 which increases the corporate income tax rate from 19% to 25% with effect from April 1, 2023 and the Company remeasured its U.K. deferred tax assets and liabilities accordingly.

The 2020 tax rate was primarily driven by the geographical distribution of income, as well as certain discrete items, primarily the favorable impacts of share-based payments and the release of a valuation allowance.

Net Income Attributable to Aon Shareholders

Net income attributable to Aon shareholders decreased to $1.3 billion, or $5.55 per diluted share, in 2021, compared to $2.0 billion, or $8.45 per diluted share, in 2020.

Consolidated Results for 2020 Compared to 2019

We have elected not to include a discussion of our consolidated results for 2020 compared to 2019 in this report in reliance upon Instruction 1 to Item 303(b) of Regulation S-K. This discussion can be found in our Annual Report on Form 10-K for the year ended December 31, 2020, which was filed with the SEC on February 19, 2021.

Non-GAAP Metrics

In our discussion of consolidated results, we sometimes refer to certain non-GAAP supplemental information derived from consolidated financial information specifically related to organic revenue growth (decline), adjusted operating margin, adjusted diluted earnings per share, free cash flow, and the impact of foreign exchange rate fluctuations on operating results. Management believes that these measures are important to make meaningful period-to-period comparisons and that this supplemental information is helpful to investors. Management also uses these measures to assess operating performance and performance for compensation. This non-GAAP supplemental information should be viewed in addition to, not instead of, our Consolidated Financial Statements.

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Organic Revenue Growth (Decline)

We use supplemental information related to organic revenue growth (decline) to help us and our investors evaluate business growth from existing operations. Organic revenue growth (decline) is a non-GAAP measure that includes the impact of intercompany activity and excludes the impact of changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures, transfers between revenue lines, and gains or losses on derivatives accounted for as hedges. This supplemental information related to organic revenue growth (decline) represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements. Industry peers provide similar supplemental information about their revenue performance, although they may not make identical adjustments. A reconciliation of this non-GAAP measure to the reported Total revenue is as follows (in millions, except percentages):

	Years Ended
	Dec 31, 2021		Dec 31, 2020		% Change		Less: Currency Impact (1)		Less: Fiduciary Investment Income (2)		Less: Acquisitions, Divestitures & Other		Organic Revenue Growth (3)
Commercial Risk Solutions	$	6,635	$	5,861	13	%	2	%	—	%	—	%	11	%
Reinsurance Solutions	1,997		1,814		10		2		—		—		8
Health Solutions	2,154		2,067		4		2		—		(8)		10
Wealth Solutions	1,426		1,341		6		3		—		1		2
Elimination	(19)		(17)		N/A		N/A		N/A		N/A		N/A
Total revenue	$	12,193	$	11,066	10	%	2	%	—	%	(1)	%	9	%

	Years Ended
	Dec 31, 2020		Dec 31, 2019		% Change		Less: Currency Impact (1)		Less: Fiduciary Investment Income (2)		Less: Acquisitions, Divestitures & Other		Organic Revenue Growth (Decline) (3)
Commercial Risk Solutions	$	5,861	$	5,857	—	%	—	%	—	%	(1)	%	1	%
Reinsurance Solutions	1,814		1,686		8		—		(1)		(1)		10
Health Solutions	2,067		2,104		(2)		(1)		—		1		(2)
Wealth Solutions	1,341		1,380		(3)		—		—		(2)		(1)
Elimination	(17)		(14)		NA		NA		NA		NA		NA
Total revenue	$	11,066	$	11,013	—	%	—	%	—	%	(1)	%	1	%

(1)Currency impact is determined by translating last year’s revenue at this year’s foreign exchange rates.

(2)Fiduciary investment income for the years ended December 31, 2021 and 2020 was $8 million and $27 million, respectively.

(3)Organic revenue growth (decline) includes the impact of intercompany activity, changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures, transfers between revenue lines, and gains or losses on derivatives accounted for as hedges.

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Adjusted Operating Margin

We use adjusted operating margin as a non-GAAP measure of core operating performance of the Company. Adjusted operating margin excludes the impact of certain items, as listed below, because management does not believe these expenses reflect our core operating performance. This supplemental information related to adjusted operating margin represents a measure not in accordance with U.S. GAAP, and should be viewed in addition to, not instead of, our Consolidated Financial Statements.

A reconciliation of this non-GAAP measure to reported operating margins is as follows (in millions, except percentages):

	Years Ended December 31
	2021			2020
Revenue	$	12,193		$	11,066
Operating income - as reported	$	2,090		$	2,781
Amortization and impairment of intangible assets	147			246
Transaction costs and other charges related to the combination and resulting termination (1)	1,436			123
Operating income - as adjusted	$	3,673		$	3,150
Operating margin - as reported	17.1		%	25.1		%
Operating margin - as adjusted	30.1		%	28.5		%

(1)As part of the terminated combination with WTW, certain transaction costs have been incurred by us in 2021. These costs may include advisory, legal, accounting, valuation, and other professional or consulting fees related to the combination, including planned divestitures that have been terminated, as well as certain compensation expenses and expenses related to further steps on our Aon United operating model as a result of the termination. Additionally, this includes the $1 billion Termination Fee paid in connection with the termination of the combination.

Adjusted Diluted Earnings per Share

We use adjusted diluted earnings per share as a non-GAAP measure of our core operating performance. Adjusted diluted earnings per share excludes the items identified above, along with pension settlements and related income taxes, because management does not believe these expenses are representative of our core earnings. This supplemental information related to adjusted diluted earnings per share represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements. A reconciliation of this non-GAAP measure to reported diluted earnings per share is as follows (in millions, except per share data and percentages):

	Year Ended December 31, 2021
	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income	$	2,090		$	1,583	$	3,673
Interest income	11			—		11
Interest expense	(322)			—		(322)
Other income (1)	152			(124)		28
Income before income taxes	1,931			1,459		3,390
Income tax expense (2)	623			—		623
Net income	1,308			1,459		2,767
Less: Net income attributable to noncontrolling interests	53			—		53
Net income attributable to Aon shareholders	$	1,255		$	1,459	$	2,714
Diluted net income per share attributable to Aon shareholders	$	5.55		$	6.45	$	12.00
Weighted average ordinary shares outstanding — diluted	226.1			—		226.1
Effective tax rates (2)	32.3		%			18.4		%

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	Year Ended December 31, 2020
	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income	$	2,781		$	369	$	3,150
Interest income	6			—		6
Interest expense	(334)			—		(334)
Other income (3)	13			—		13
Income before income taxes	2,466			369		2,835
Income tax expense (2)	448			51		499
Net income	2,018			318		2,336
Less: Net income attributable to noncontrolling interests	49			—		49
Net income attributable to Aon shareholders	$	1,969		$	318	$	2,287
Diluted net income per share attributable to Aon shareholders	$	8.45		$	1.36	$	9.81
Weighted average ordinary shares outstanding — diluted	233.1			—		233.1
Effective tax rates (2)	18.2		%			17.6		%

(1)Adjusted Other income excludes gains from dispositions of $124 million, for the year ended December 31, 2021.

(2)Adjusted items are generally taxed at the estimated annual effective tax rate, except for the applicable tax impact associated with accelerated tradename amortization, impairment charges, certain gains from dispositions, and certain transaction costs and other charges related to the combination and resulting termination, which are adjusted at the related jurisdictional rate. In addition, income tax expense for the year ended December 30, 2021 excludes the impact of remeasuring the net deferred tax liabilities in the U.K. as a result of the corporate income tax rate increase enacted in the second quarter of 2021.

(3)There was $1 million of income for the year ended December 31, 2020, including the related tax effect, from discontinued operations recognized in Net Income from discontinued operations in the Consolidated Statement of Income.

Free Cash Flow

We use free cash flow, defined as cash flow provided by operations minus capital expenditures, as a non-GAAP measure of our core operating performance and cash generating capabilities of our business operations. This supplemental information related to free cash flow represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, the Consolidated Financial Statements. The use of this non-GAAP measure does not imply or represent the residual cash flow for discretionary expenditures. A reconciliation of this non-GAAP measure to cash flow provided by operations is as follows (in millions):

	Years Ended December 31
	2021		2020
Cash provided by operating activities	$	2,182	$	2,783
Capital expenditures	(137)		(141)
Free cash flow	$	2,045	$	2,642

Impact of Foreign Currency Exchange Rate Fluctuations

Because we conduct business in more than 120 countries, foreign currency exchange rate fluctuations have a significant impact on our business. Foreign currency exchange rate movements may be significant and may distort true period-to-period comparisons of changes in revenue or pretax income. Therefore, to give financial statement users meaningful information about our operations, we have provided an illustration of the impact of foreign currency exchange rate fluctuations on our financial results. The methodology used to calculate this impact isolates the impact of the change in currencies between periods by translating the prior year’s revenue, expenses, and net income using the current year’s foreign currency exchange rates.

Currency fluctuations had a favorable impact of $0.17 on earnings per diluted share during the year ended December 31, 2021 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.03 on earnings per diluted share during the year ended December 31, 2020, if 2019 results were translated at 2020 rates.

Currency fluctuations had a favorable impact of $0.23 on adjusted earnings per diluted share during the year ended December 31, 2021 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.04 on adjusted earnings per diluted share during the year ended December 31, 2020, if 2019

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results were translated at 2020 rates. These translations are performed for comparative and illustrative purposes only and do not impact the accounting policies or practices for amounts included in our Financial Statements.

LIQUIDITY AND FINANCIAL CONDITION

Liquidity

Executive Summary

We believe that our balance sheet and strong cash flow provide us with adequate liquidity. Our primary sources of liquidity in the near-term include cash flows provided by operations and available cash reserves; primary sources of liquidity in the long-term include cash flows provided by operations, debt capacity available under our credit facilities and capital markets. Our primary uses of liquidity are operating expenses and investments, capital expenditures, acquisitions, share repurchases, pension obligations, and shareholder dividends. We believe that cash flows from operations, available credit facilities, available cash reserves, and the capital markets will be sufficient to meet our liquidity needs, including principal and interest payments on debt obligations, capital expenditures, pension contributions, and anticipated working capital requirements in the next twelve months and over the long-term. Although there continues to be uncertainties around future economic conditions due to COVID-19, we have largely returned to normal levels of liquidity and will continue to monitor our needs as economic conditions change.

In the third quarter of 2021, the Combination with WTW was terminated and on July 27, 2021, we paid the Termination Fee of $1 billion. Refer to “Termination of Business Combination Agreement” within Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for further information. The Termination Fee, along with other payments made in the third and fourth quarters related to terminating the combination with WTW, are reflected as an outflow to operating activities.

Cash on our balance sheet includes funds available for general corporate purposes, as well as amounts restricted as to their use. Funds held on behalf of clients in a fiduciary capacity are segregated and shown together with uncollected insurance premiums and claims in Fiduciary assets in the Consolidated Statements of Financial Position, with a corresponding amount in Fiduciary liabilities.

In our capacity as an insurance broker or agent, we collect premiums from insureds and, after deducting our commission, remit the premiums to the respective insurance underwriters. We also collect claims or refunds from underwriters on behalf of insureds, which are then returned to the insureds. Unremitted insurance premiums and claims are held by us in a fiduciary capacity. The levels of funds held on behalf of clients and liabilities can fluctuate significantly depending on when we collect the premiums, claims, and refunds, make payments to underwriters and insureds, and collect funds from clients and make payments on their behalf, and upon the impact of foreign currency movements. Funds held on behalf of clients, because of their nature, are generally invested in very liquid securities with highly rated, credit-worthy financial institutions. Fiduciary assets include funds held on behalf of clients comprised of cash and cash equivalents of $6.1 billion and $5.7 billion at December 31, 2021 and 2020, and fiduciary receivables of $8.3 billion and $8.1 billion at December 31, 2021 and 2020, respectively. While we earn investment income on the funds held in cash and money market funds, the funds cannot be used for general corporate purposes.

We maintain multi-currency cash pools with third-party banks in which various Aon entities participate. Individual Aon entities are permitted to overdraw on their individual accounts provided the overall global balance does not fall below zero. At December 31, 2021, non-U.S. cash balances of one or more entities may have been negative; however, the overall balance was positive.

The following table summarizes our Cash and cash equivalents, Short-term investments, and Fiduciary assets as of December 31, 2021 (in millions):

	Statement of Financial Position Classification
Asset Type	Cash and cash equivalents		Short-term investments		Fiduciary assets		Total
Certificates of deposit, bank deposits, or time deposits	$	544	$	—	$	3,475	$	4,019
Money market funds	—		292		2,626		2,918
Cash, Short-term investments, and Funds held on behalf of clients	544		292		6,101		6,937
Fiduciary receivables	—		—		8,285		8,285
Total	$	544	$	292	$	14,386	$	15,222

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Cash and cash equivalents and Funds held on behalf of clients increased $72 million in 2021 compared to 2020. A summary of our cash flows provided by and used for operating, investing, and financing activities is as follows (in millions):

	Years Ended December 31
	2021		2020 (1) (As Revised)
Cash provided by operating activities	$	2,182	$	2,783
Cash provided by (used for) investing activities	$	49	$	(679)
Cash used for financing activities	$	(1,924)	$	(1,772)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	$	(235)	$	297

(1) Certain amounts on the Consolidated Statements of Cash Flows as presented in our financial statements previously filed in the Company’s Annual Reports on Form 10-K have been restated. Refer to Note 1 “Basis of Presentation” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report.

Operating Activities

Net cash provided by operating activities during the year ended December 31, 2021 decreased $601 million, or 22%, from the prior year to $2,182 million. This amount represents net income reported, as adjusted for gains or losses on sales of businesses, share-based compensation expense, depreciation expense, amortization and impairments, and other non-cash income and expenses, as well as changes in working capital that relate primarily to the timing of payments of accounts payable and accrued liabilities and the collection of receivables.

Pension Contributions

Pension contributions were $87 million for the year ended December 31, 2021, as compared to $120 million for the year ended December 31, 2020. In 2022, we expect to contribute approximately $74 million in cash to our pension plans, including contributions to non-U.S. pension plans, which are subject to changes in foreign exchange rates.

Investing Activities

Cash flows provided by investing activities during the year ended December 31, 2021 were $49 million, an increase of $728 million compared to prior year. Generally, the primary drivers of cash flows provided by investing activities are sales of businesses, sales of short-term investments, and proceeds from investments. Generally, the primary drivers of cash flows used for investing activities are acquisition of businesses, purchases of short-term investments, capital expenditures, and payments for investments. The gains and losses corresponding to cash flows provided by proceeds from investments and used for payments for investments are primarily recognized in Other income in the Consolidated Statements of Income.

Short-term Investments

Short-term investments decreased $16 million at December 31, 2021 as compared to December 31, 2020. As disclosed in Note 14 “Fair Value Measurements and Financial Instruments” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report, the majority of our investments carried at fair value are money market funds. These money market funds are held throughout the world with various financial institutions. We are not aware of any market liquidity issues that would materially impact the fair value of these investments.

Acquisitions and Dispositions of Businesses

During 2021, the Company completed the acquisition of two businesses for consideration of $14 million, net of cash and funds held on behalf of clients, and the disposition of six businesses for a $218 million cash inflow, net of cash and funds held on behalf of clients.

During 2020, the Company completed the acquisition of six businesses for consideration of $368 million, net of cash and funds held on behalf of clients, and the disposition of one business for a $30 million cash inflow, net of cash and funds held on behalf of clients.

Capital Expenditures

The Company’s additions to fixed assets, including capitalized software, which amounted to $137 million in 2021 and $141 million in 2020, primarily related to the refurbishing and modernizing of office facilities, software development costs, and computer equipment purchases.

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Financing Activities

Cash flows used for financing activities during the year ended December 31, 2021 was $1,924 million, an increase of $152 million compared to prior year. Generally, the primary drivers of cash flows used for financing activities are issuances of debt, net of repayments, share repurchases, change in net fiduciary liabilities, dividends paid to shareholders, issuances of shares for employee benefit plans, transactions with noncontrolling interests, and other financing activities, such as collection of or payments for deferred consideration in connection with prior-year business acquisitions and divestitures.

Share Repurchase Program

We have a share repurchase program authorized by our Board of Directors. The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases, and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in authorized repurchases in February 2022 for a total of $27.5 billion in repurchase authorizations.

The following table summarizes the Company’s Share Repurchase activity (in millions, except per share data):

	Years Ended December 31
	2021		2020
Shares repurchased	12.4		8.5
Average price per share	$	286.82	$	206.28
Costs recorded to retained earnings
Total repurchase cost	$	3,543	$	1,761
Additional associated costs	—		2
Total costs recorded to retained earnings	$	3,543	$	1,763

At December 31, 2021, the remaining authorized amount for share repurchase under the Repurchase Program was approximately $1.7 billion. Under the Repurchase Program, we have repurchased a total of 149.6 million shares for an aggregate cost of approximately $18.3 billion.

Borrowings

Total debt at December 31, 2021 was $9.4 billion, an increase of $1.7 billion compared to December 31, 2020. Commercial paper activity during the years ended December 31, 2021 and 2020 is as follows (in millions):

	Years Ended December 31
	2021		2020
Total issuances (1)	$	4,478	$	3,162
Total repayments	(3,807)		(3,275)
Net issuances (repayments)	$	671	$	(113)

(1) The proceeds of the commercial paper issuances were used primarily for short-term working capital needs.

Commercial paper may be issued in aggregate principal amounts of up to $1 billion under the U.S. Program and €625 million under the European Program, not to exceed the amount of our committed credit facilities, which was $1.75 billion at December 31, 2021. The aggregate capacity of the U.S. Program was increased in the fourth quarter of 2021 from $900 million to $1 billion. The aggregate capacity of the Commercial Paper Program remains fully backed by our committed credit facilities.

Proceeds from commercial paper issued by Aon Corporation under the U.S. Program, where the aggregate principal was raised on July 26, 2021, were used to pay approximately $400 million of the Termination Fee on July 27, 2021.

On December 2, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales, co-issued $500 million aggregate principal amount of 2.60% Senior Notes set to mature on December 2, 2031. We intend to use the net proceeds of the offering for general corporate purposes.

In November 2021, the Company’s $500 million 2.20% Senior Notes due November 2022 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statements of Financial Position as the date of maturity is in less than one year as of December 31, 2021.

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On August 23, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales, both wholly owned subsidiaries of the Company, co-issued $400 million of 2.05% Senior Notes due August 2031 and $600 million of 2.90% Senior Notes due August 2051. We intend to use the net proceeds from the offering for general corporate purposes.

On January 13, 2021, Aon Global Limited, a limited company organized under the laws of England and Wales and a wholly owned subsidiary of Aon plc, issued an irrevocable notice of redemption to holders of its 2.80% Senior Notes for the redemption of all $400 million outstanding aggregate principal amount of the notes, which were set to mature in March 2021 and classified as Short-term debt and current portion of long-term debt as of December 31, 2020. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

On May 29, 2020, Aon Corporation, a Delaware corporation and a wholly owned subsidiary of the Company, issued an irrevocable notice of redemption to holders of its 5.00% Senior Notes, which were set to mature on September 30, 2020, for the redemption of all $600 million outstanding aggregate principal amount of the notes. The redemption date was on June 30, 2020 and resulted in a loss of $7 million due to extinguishment.

On May 12, 2020, Aon Corporation issued $1 billion 2.80% Senior Notes due May 2030. Aon Corporation used a portion of the net proceeds on June 30, 2020 to repay its outstanding 5.00% Senior Notes, which were set to mature on September 30, 2020. We used the remainder to repay other borrowings and for general corporate purposes.

Other Liquidity Matters

Distributable Profits

We are required under Irish law to have available “distributable profits” to make share repurchases or pay dividends to shareholders. Distributable profits are created through the earnings of the Irish parent company and, among other methods, through intercompany dividends or a reduction in share capital approved by the High Court of Ireland. Distributable profits are not linked to a U.S. GAAP reported amount (e.g. retained earnings). On July 16, 2021, we received approval from the High Court of Ireland to complete a reduction in share premium to create distributable profits of $34.0 billion to support the payment of possible future dividends or future share repurchases, if and to the extent declared by the directors in compliance with their duties under Irish law. As of December 31, 2021 and December 31, 2020, we had distributable profits in excess of $32.7 billion and $0.2 billion, respectively. We believe that we will have sufficient distributable profits for the foreseeable future.

Credit Facilities

We expect cash generated by operations for 2021 to be sufficient to service our debt and contractual obligations, finance capital expenditures, and continue to pay dividends to our shareholders. Although cash from operations is expected to be sufficient to service these activities, we have the ability to access the commercial paper markets or borrow under our credit facilities to accommodate any timing differences in cash flows. Additionally, under current market conditions, we believe that we could access capital markets to obtain debt financing for longer-term funding, if needed.

As of December 31, 2021, we had two primary committed credit facilities outstanding: our $1.0 billion multi-currency U.S. credit facility expiring in September 2026 and our $750 million multi-currency U.S. credit facility expiring in October 2023. In aggregate, these two facilities provide $1.75 billion in available credit. The $1.0 billion credit facility was entered into on September 28, 2021 and replaced the $900 million credit facility, which was scheduled to mature on February 2, 2022.

Each of these primary committed credit facilities includes customary representations, warranties, and covenants, including financial covenants that require us to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to consolidated adjusted EBITDA, tested quarterly. At December 31, 2021, we did not have borrowings under either facility, and we were in compliance with the financial covenants and all other covenants contained therein during the rolling year ended December 31, 2021.

Shelf Registration Statement

On May 12, 2020, we filed a shelf registration statement with the SEC, registering the offer and sale from time to time of an indeterminate amount of, among other securities, debt securities, preference shares, Class A Ordinary Shares and convertible securities. Our ability to access the market as a source of liquidity is dependent on investor demand, market conditions, and other factors.

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Rating Agency Ratings

The major rating agencies’ ratings of our debt at February 18, 2022 appear in the table below.

	Ratings
	Senior Long-term Debt	Commercial Paper	Outlook
Standard & Poor’s	A-	A-2	Stable
Moody’s Investor Services	Baa2	P-2	Stable
Fitch, Inc.	BBB+	F-2	Stable

Guarantees in Connection with the Sale of the Divested Business

In connection with the sale of the Divested Business, we guaranteed future operating lease commitments related to certain facilities assumed by the Buyer. We are obligated to perform under the guarantees if the Divested Business defaults on the leases at any time during the remainder of the lease agreements, which expire on various dates through 2025. As of December 31, 2021, the undiscounted maximum potential future payments under the lease guarantee were $40 million, with an estimated fair value of $5 million. No cash payments were made in connection to the lease commitments during the year ended December 31, 2021.

Additionally, we are subject to performance guarantee requirements under certain client arrangements that were assumed by the Buyer. Should the Divested Business fail to perform as required by the terms of the arrangements, we would be required to fulfill the remaining contract terms, which expire on various dates through 2023. As of December 31, 2021, the undiscounted maximum potential future payments under the performance guarantees were $52 million, with an estimated fair value of less than $1 million. No cash payments were made in connection to the performance guarantees during the year ended December 31, 2021.

Letters of Credit and Other Guarantees

We have entered into a number of arrangements whereby our performance on certain obligations is guaranteed by a third party through the issuance of an LOC. We had total LOCs outstanding of approximately $75 million at December 31, 2021, compared to $79 million at December 31, 2020. These LOCs cover the beneficiaries related to certain of our U.S. and Canadian non-qualified pension plan schemes and secure deductible retentions for our own workers’ compensation program. We also have obtained LOCs to cover contingent payments for taxes and other business obligations to third parties, and other guarantees for miscellaneous purposes at our international subsidiaries.

We have certain contractual contingent guarantees for premium payments owed by clients to certain insurance companies. The maximum exposure with respect to such contractual contingent guarantees was approximately $153 million at December 31, 2021, compared to $113 million at December 31, 2020.

Contractual Obligations

Our contractual obligations and commitments as of December 31, 2021 are comprised of principal payments on debt, interest payments on debt, operating leases, pension and other postretirement benefit plans, and purchase obligations.

Operating leases are primarily comprised of leased office space throughout the world. As leases expire, we do not anticipate difficulty in negotiating renewals or finding other satisfactory space if the premise becomes unavailable. In certain circumstances, we may have unused space and may seek to sublet such space to third parties, depending upon the demands for office space in the locations involved. Refer to Note 8 “Lease Commitments” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report for further information.

Pension and other postretirement benefit plan obligations include estimates of our minimum funding requirements pursuant to the ERISA and other regulations, as well as minimum funding requirements agreed with the trustees of our U.K. pension plans. Additional amounts may be agreed to with, or required by, the U.K. pension plan trustees. Nonqualified pension and other postretirement benefit obligations are based on estimated future benefit payments. We may make additional discretionary contributions. Refer to Note 11 “Employee Benefits” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report for further information.

Purchase obligations are defined as agreements to purchase goods and services that are enforceable and legally binding on us, and that specifies all significant terms, including the goods to be purchased or services to be rendered, the price at which the goods or services are to be rendered, and the timing of the transactions. Most of our purchase obligations are related to purchases of information technology services or other service contracts.

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We had no other cash requirements from known contractual obligations and commitments that have, or are reasonably likely to have, a current or future material effect on the Company’s financial condition, results of operations, or liquidity.

Guarantee of Registered Securities

In connection with the Reorganization, on April 1, 2020 Aon plc and Aon Global Holdings plc, a company incorporated under the laws of England and Wales, entered into various agreements pursuant to which they agreed to guarantee the obligations of Aon Corporation arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Global Limited and the obligations of Aon Global Limited arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Corporation. Those agreements include: (1) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, and Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”) (amending and restating the Amended and Restated Indenture, dated April 2, 2012, among Aon Corporation, Aon Global Limited and the Trustee); (2) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 12, 2012, among Aon Corporation, Aon Global Limited plc and the Trustee); (3) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated May 20, 2015, among Aon Corporation, Aon Global Limited and the Trustee); (4) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated November 13, 2015, among Aon Corporation, Aon Global Limited and the Trustee); and (5) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 3, 2018, among Aon Corporation, Aon Global Limited and the Trustee).

After the Reorganization, newly issued and outstanding debt securities by Aon Corporation are guaranteed by Aon Global Limited, Aon plc, and Aon Global Holdings plc, and include the following (collectively, the “Aon Corporation Notes”):

Aon Corporation Notes

2.20% Senior Notes due November 2022

8.205% Junior Subordinated Notes due January 2027

4.50% Senior Notes due December 2028

3.75% Senior Notes due May 2029

2.80% Senior Notes due 2030

6.25% Senior Notes due September 2040

All guarantees of Aon plc, Aon Global Limited, and Aon Global Holdings plc of the Aon Corporation Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the company. There are no subsidiaries other than those listed above that guarantee the Aon Corporation Notes.

After the Reorganization, newly issued and outstanding debt securities by Aon Global Limited are guaranteed by Aon plc, Aon Global Holdings plc, and Aon Corporation, and include the following (collectively, the “Aon Global Limited Notes”):

Aon Global Limited Notes

4.00% Senior Notes due November 2023

3.50% Senior Notes due June 2024

3.875% Senior Notes due December 2025

2.875% Senior Notes due May 2026

4.25% Senior Notes due December 2042

4.45% Senior Notes due May 2043

4.60% Senior Notes due June 2044

4.75% Senior Notes due May 2045

All guarantees of Aon plc, Aon Global Holdings plc, and Aon Corporation of the Aon Global Limited Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future

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unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the company. There are no subsidiaries other than those listed above that guarantee the Aon Global Limited Notes.

Newly co-issued and outstanding debt securities by Aon Corporation and Aon Global Holdings plc (together, the “Co-Issuers”) are guaranteed by Aon plc and Aon Global Limited and include the following (collectively, the “Co-Issued Notes”):

Co-Issued Notes - Aon Corporation and Aon Global Holdings plc

2.05% Senior Notes due August 2031

2.60% Senior Notes due December 2031

2.90% Senior Notes due August 2051

All guarantees of Aon plc and Aon Global Limited of the Co-Issued Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the Co-Issuers. There are no subsidiaries other than those listed above that guarantee the Co-Issued Notes.

Aon Corporation, Aon Global Limited, and Aon Global Holdings plc are indirect wholly owned subsidiaries of Aon plc. Aon plc, Aon Global Limited, Aon Global Holdings plc, and Aon Corporation together comprise the “Obligor group”. The following tables set forth summarized financial information for the Obligor group.

Adjustments are made to the tables to eliminate intercompany balances and transactions between the Obligor group. Intercompany balances and transactions between the Obligor group and non-guarantor subsidiaries are presented as separate line items within the summarized financial information. These balances are presented on a net presentation basis, rather than a gross basis, as this better reflects the nature of the intercompany positions and presents the funding or funded position that is to be received or owed. No balances or transactions of non-guarantor subsidiaries are presented in the summarized financial information, including investments of the Obligor group in non-guarantor subsidiaries. Summarized Statement of Income information for the Obligor group is as follows (in millions):

	Obligor Group
	Summarized Statement of Income Information
	Year Ended December 31, 2021
Revenue	$	—
Operating loss	$	(1,156)
Expense from non-guarantor subsidiaries before income taxes	$	(778)
Net loss	$	(2,120)
Net loss attributable to Aon shareholders	$	(2,120)

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Summarized Statement of Financial Position information for the Obligor group is as follows (in millions):

	Obligor Group
	Summarized Statement of Financial Position Information
	As of December 31, 2021
Receivables due from non-guarantor subsidiaries	$	1,646
Other current assets	57
Total current assets	$	1,703
Non-current receivables due from non-guarantor subsidiaries	$	498
Other non-current assets	882
Total non-current assets	$	1,380
Payables to non-guarantor subsidiaries	$	13,509
Other current liabilities	2,013
Total current liabilities	$	15,522
Non-current payables to non-guarantor subsidiaries	$	7,139
Other non-current liabilities	9,512
Total non-current liabilities	$	16,651

CRITICAL ACCOUNTING POLICIES AND ESTIMATES

The Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. To prepare these financial statements, we make estimates, assumptions, and judgments that affect what we report as our assets and liabilities, what we disclose as contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of revenues and expenses during the periods presented.

In accordance with our policies, we regularly evaluate our estimates, assumptions, and judgments, including, but not limited to, those concerning revenue recognition, pensions, goodwill and other intangible assets, contingencies, share-based payments, and income taxes, and base our estimates, assumptions, and judgments on our historical experience and on factors we believe reasonable under the circumstances. The results involve judgments about the carrying values of assets and liabilities not readily apparent from other sources. If our assumptions or conditions change, the actual results we report may differ from these estimates. We believe the following critical accounting policies affect the more significant estimates, assumptions, and judgments we use to prepare these Consolidated Financial Statements.

Revenue Recognition

The Company recognizes revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, the Company assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, the Company allocates consideration based on their relative fair values.

Costs incurred by the Company in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services

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to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units transferred and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly, over the term of the arrangement in installments based on deposit or minimum premiums for most treaty reinsurance arrangements.

Health Solutions includes consulting and brokerage, Human Capital, and voluntary benefits and enrollment solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services using input or output measures, including units delivered or time elapsed, to provide a faithful depiction of the progress towards completion of the performance obligation. For Human Capital, revenue is recognized over time or at a point in time upon completion of the services. For arrangements recognized over time, revenue is based on a measure of progress that depicts the transfer of control of the services to the customer utilizing an appropriate input or output measure to provide a faithful depiction of the progress towards completion of the performance obligation, including units delivered or time elapsed. Input and output measures utilized vary based on the arrangement but typically include reports provided or days elapsed. Revenue from voluntary benefits and enrollment solutions arrangements are typically recognized upon successful enrollment of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

Wealth Solutions includes retirement consulting, pension administration and investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Pensions

We sponsor defined benefit pension plans throughout the world. Our most significant plans are located in the U.S., the U.K., the Netherlands, and Canada, which are closed to new entrants. We have ceased crediting future benefits relating to salary and services for our U.S., U.K., Netherlands, and Canada plans to the extent statutorily permitted.

The service cost component of net periodic benefit cost is reported in Compensation and benefits and all other components are reported in Other income. We used a full-yield curve approach in the estimation of the service and interest cost components of net periodic pension and postretirement benefit cost for our major pension and other postretirement benefit plans; this was obtained by applying the specific spot rates along the yield curve used in the determination of the benefit obligation to the relevant projected cash flows.

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Recognition of Gains and Losses and Prior Service

Certain changes in the value of the obligation and in the value of plan assets, which may occur due to various factors such as changes in the discount rate and actuarial assumptions, actual demographic experience, and/or plan asset performance are not immediately recognized in net income. Such changes are recognized in Other comprehensive income and are amortized into net income as part of the net periodic benefit cost.

Unrecognized gains and losses that have been deferred in Other comprehensive income, as previously described, are amortized into expense as a component of periodic pension expense based on the average life expectancy of the U.S., U.K., Netherlands, and Canada plan members. We amortize any prior service expense or credits that arise as a result of plan changes over a period consistent with the amortization of gains and losses.

As of December 31, 2021, our pension plans have deferred losses that have not yet been recognized through income in the Consolidated Financial Statements. We amortize unrecognized actuarial losses outside of a corridor, which is defined as 10% of the greater of market-related value of plan assets or PBO. To the extent not offset by future gains, incremental amortization as calculated above will continue to affect future pension expense similarly until fully amortized.

The following table discloses our accumulated other comprehensive loss, the number of years over which we are amortizing the loss, and the estimated 2022 amortization of loss by country (in millions, except amortization period):

	U.K.		U.S.		Other
Accumulated other comprehensive loss	$	1,255	$	1,551	$	483
Amortization period	7 - 26		6 - 23		11 - 35
Estimated 2022 amortization of loss	$	34	$	67	$	14

The U.S. had no unrecognized prior service cost (credit) at December 31, 2021. The unrecognized prior service cost (credit) at December 31, 2021 was $40 million, and $(6) million for the U.K. and other plans, respectively.

For the U.S. pension plans, we use a market-related valuation of assets approach to determine the expected return on assets, which is a component of net periodic benefit cost recognized in the Consolidated Statements of Income. This approach recognizes 20% of any gains or losses in the current year’s value of market-related assets, with the remaining 80% spread over the next four years. As this approach recognizes gains or losses over a five-year period, the future value of assets and therefore, our net periodic benefit cost will be impacted as previously deferred gains or losses are recorded. As of December 31, 2021, the market-related value of assets was $2.2 billion. We do not use the market-related valuation approach to determine the funded status of the U.S. plans recorded in the Consolidated Statements of Financial Position. Instead, we record and present the funded status in the Consolidated Statements of Financial Position based on the fair value of the plan assets. As of December 31, 2021, the fair value of plan assets was $2.4 billion. Our non-U.S. plans use fair value to determine expected return on assets.

Rate of Return on Plan Assets and Asset Allocation

The following table summarizes the expected long-term rate of return on plan assets for future pension expense as of December 31, 2021:

	U.K.	U.S.	Other
Expected return on plan assets, net of administration expenses	2.34%	2.03 - 5.28%	1.80 - 3.15%

In determining the expected rate of return for the plan assets, we analyze investment community forecasts and current market conditions to develop expected returns for each of the asset classes used by the plans. In particular, we surveyed multiple third-party financial institutions and consultants to obtain long-term expected returns on each asset class, considered historical performance data by asset class over long periods, and weighted the expected returns for each asset class by target asset allocations of the plans.

The U.S. pension plan asset allocation is based on approved allocations following adopted investment guidelines. The investment policy for U.K. and other non-U.S. pension plans is generally determined by the plans’ trustees. Because there are several pension plans maintained in the U.K. and other non-U.S. categories, our target allocation presents a range of the target allocation of each plan. Target allocations are subject to change.

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Impact of Changing Economic Assumptions

Changes in the discount rate and expected return on assets can have a material impact on pension obligations and pension expense.

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our discount rate would have on our PBO at December 31, 2021 (in millions):

Increase (decrease) in projected benefit obligation (1)	25 BPS Change in Discount Rate
	Increase		Decrease
U.K. plans	$	(201)	$	219
U.S. plans	$	(89)	$	93
Other plans	$	(64)	$	69

(1)Increases to the PBO reflect increases to our pension obligations, while decreases in the PBO are recoveries toward fully-funded status. A change in the discount rate has an inverse relationship to the PBO.

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our discount rate would have on our estimated 2022 pension expense (in millions):

	25 BPS Change in Discount Rate
Increase (decrease) in expense	Increase		Decrease
U.K. plans	$	(1)	$	1
U.S. plans	$	2	$	(2)
Other plans	$	1	$	(1)

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our long-term rate of return on plan assets would have on our estimated 2022 pension expense (in millions):

	25 BPS Change in Long-Term Rate of Return on Plan Assets
Increase (decrease) in expense	Increase		Decrease
U.K. plans	$	(15)	$	15
U.S. plans	$	(5)	$	5
Other plans	$	(4)	$	4

The net unfunded pension balance has continued to improve in 2021, reflecting continued progress in reducing the funded status at risk. As a result, the potential impact of a hypothetical adverse change in discount rates and return seeking asset exposures would have a less significant impact as compared to prior years. A hypothetical discount rates decrease of 1% and return seeking assets decline of 10% would have resulted in expected balance sheet deterioration at 2021 of approximately $235 million, as compared to approximately $410 million in 2019, an improvement of approximately $175 million. This is largely due to greater amounts of liability matching assets and de-risking actions.

Estimated Future Contributions

We estimate cash contributions of approximately $74 million to our pension plans in 2022 as compared with cash contributions of $87 million in 2021.

Goodwill and Other Intangible Assets

Goodwill represents the excess of cost over the fair market value of the net assets acquired. We classify our intangible assets acquired as either tradenames, customer-related and contract-based, or technology and other.

Goodwill is not amortized, but rather tested for impairment at least annually in the fourth quarter. We test more frequently if there are indicators of impairment or whenever business circumstances suggest that the carrying value of goodwill may not be recoverable. These indicators may include a sustained significant decline in our share price and market capitalization, a decline in our expected future cash flows, or a significant adverse change in legal factors or in the business climate, among others.

We perform impairment reviews at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment (referred to as a “component”). A component of an operating segment is a reporting unit if the component

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constitutes a business for which discrete financial information is available and segment management regularly reviews the operating results of that component. An operating segment shall be deemed to be a reporting unit if all of its components are similar, if none of its components are a reporting unit, or if the segment comprises only a single component.

When evaluating these assets for impairment, we may first perform a qualitative assessment to determine whether it is more likely than not that a reporting unit is impaired. If we do not perform a qualitative assessment, or if we determine that it is not more likely than not that the fair value of the reporting unit exceeds its carrying amount, then the goodwill impairment test becomes a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit.

In determining the fair value of our reporting units, we use a DCF model based on our most current forecasts. We discount the related cash flow forecasts using the weighted average cost of capital method at the date of evaluation. Preparation of forecasts and selection of the discount rate for use in the DCF model involve significant judgments, and changes in these estimates could affect the estimated fair value of one or more of our reporting units and could result in a goodwill impairment charge in a future period. We also use market multiples which are obtained from quoted prices of comparable companies to corroborate our DCF model results. The combined estimated fair value of our reporting units from our DCF model often results in a premium over our market capitalization, commonly referred to as a control premium. We believe the implied control premium determined by our impairment analysis is reasonable based upon historic data of premiums paid on actual transactions within our industry.

We review intangible assets that are being amortized for impairment whenever events or changes in circumstance indicate that their carrying amount may not be recoverable. If we are required to record impairment charges in the future, they could materially impact our results of operations.

Contingencies

We define a contingency as an existing condition that involves a degree of uncertainty as to a possible gain or loss that will ultimately be resolved when one or more future events occur or fail to occur. Under U.S. GAAP, we are required to establish reserves for loss contingencies when the loss is probable and we can reasonably estimate its financial impact. We are required to assess the likelihood of material adverse judgments or outcomes, as well as potential ranges or probability of losses. We determine the amount of reserves required, if any, for contingencies after carefully analyzing each individual item. The required reserves may change due to new developments in each issue. We do not recognize gain contingencies until the contingency is resolved and amounts due are probable of collection.

Share-Based Payments

Share-based compensation expense is measured based on the grant date fair value and recognized over the requisite service period for awards that we ultimately expect to vest. For purposes of measuring share-based compensation expense, we consider whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2021, 2020, or 2019. We also estimate forfeitures at the time of grant based on our actual experience to date and revise our estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

Restricted Share Units

RSUs are service-based awards for which we recognize the associated compensation cost on a straight-line basis over the requisite service period. We estimate the fair value of the awards based on the market price of the underlying share on the date of grant, reduced by the present value of estimated dividends foregone during the vesting period where applicable.

Performance Share Awards

PSAs are performance-based awards for which vesting is dependent on the achievement of certain objectives. Such objectives may be made on a personal, group or company level. We estimate the fair value of the awards based on the market price of the underlying share on the date of grant, reduced by the present value of estimated dividends foregone during the vesting period.

Compensation expense is recognized over the performance period. The number of shares issued on the vesting date will vary depending on the actual performance objectives achieved, which are based on a fixed number of potential outcomes. We make assessments of future performance using subjective estimates, such as long-term plans. As a result, changes in the underlying assumptions could have a material impact on the compensation expense recognized.

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The largest plan is the LPP, which has a three-year performance period. As the percent of expected performance increases or decreases, the potential change in expense can go from 0% to 200% of the targeted total expense. The 2019 to 2021 performance period ended on December 31, 2021, the 2018 to 2020 performance period ended on December 31, 2020, and the 2017 to 2019 performance period ended on December 31, 2019. The LPP currently has two open performance periods: 2020 to 2022 and 2021 to 2023. A 10% upward adjustment in our estimated performance achievement percentage for both open performance periods would not have increased our 2021 expense, while a 10% downward adjustment would have decreased our expense by approximately $7.6 million.

Income Taxes

We earn income in numerous countries and this income is subject to the laws of taxing jurisdictions within those countries.

The carrying values of deferred income tax assets and liabilities reflect the application of our income tax accounting policies and are based on management’s assumptions and estimates about future operating results and levels of taxable income, and judgments regarding the interpretation of the provisions of current accounting principles.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Considerations with respect to the realizability of deferred tax assets include the period of expiration of the deferred tax asset, historical earnings and projected future taxable income by jurisdiction as well as tax liabilities for the tax jurisdiction to which the tax asset relates. Significant management judgment is required in determining the assumptions and estimates related to the amount and timing of future taxable income. Valuation allowances are evaluated periodically and will be subject to change in each future reporting period as a result of changes in various factors.

We assess carryforwards and tax credits for realization as a reduction of future taxable income by using a “more likely than not” determination.

We base the carrying values of liabilities and assets for income taxes currently payable and receivable on management’s interpretation of applicable tax laws and incorporate management’s assumptions and judgments about using tax planning strategies in various taxing jurisdictions. Using different estimates, assumptions, and judgments in accounting for income taxes, especially those that deploy tax planning strategies, may result in materially different carrying values of income tax assets and liabilities and changes in our results of operations.

NEW ACCOUNTING PRONOUNCEMENTS

Note 2 “Summary of Significant Accounting Principles and Practices” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report contains a summary of our significant accounting policies, including a discussion of recently issued accounting pronouncements and their impact or future potential impact on our financial results, if determinable.

Item 7A.    Quantitative and Qualitative Disclosures About Market Risk

We are exposed to potential fluctuations in earnings, cash flows, and the fair values of certain of our assets and liabilities due to changes in interest rates and foreign exchange rates. To manage the risk from these exposures, we enter into a variety of derivative instruments. We do not enter into derivatives or financial instruments for trading or speculative purposes.

The following discussion describes our specific exposures and the strategies we use to manage these risks. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report for a discussion of our accounting policies for financial instruments and derivatives.

Foreign Exchange Risk

We are subject to foreign exchange rate risk. Our primary exposures include exchange rates between the U.S. dollar and the euro, the British pound, the Canadian dollar, the Australian dollar, the Indian rupee, and the Japanese yen. We use over-the-counter options and forward contracts to reduce the impact of foreign currency risk to our financial statements.

Additionally, some of our non-U.S. brokerage subsidiaries receive revenue in currencies that differ from their functional currencies. Our U.K. subsidiaries earn a portion of their revenue in U.S. dollars, euro, and Japanese yen, but most of their expenses are incurred in British pounds. At December 31, 2021, we have hedged approximately 45% of our U.K. subsidiaries’ expected exposures to the U.S. dollar, euro, and Japanese yen transactions for the years ending December 31, 2022 and 2023. We generally do not hedge exposures beyond three years.

We also use forward and option contracts to economically hedge foreign exchange risk associated with monetary balance sheet exposures, such as intercompany notes and current assets and liabilities that are denominated in a non-functional currency and are subject to remeasurement.

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The potential loss in future earnings from foreign exchange derivative instruments resulting from a hypothetical 10% adverse change in year-end exchange rates would be $48 million and $10 million at December 31, 2022 and 2023, respectively.

The translated value of revenues and expenses from our international brokerage operations are subject to fluctuations in foreign exchange rates. If we were to translate prior year results at current year exchange rates, diluted earnings per share would have a favorable $0.17 impact during the year ended December 31, 2021. Further, adjusted diluted earnings per share, a non-GAAP measure as defined and reconciled under the caption “Review of Consolidated Results — Adjusted Diluted Earnings Per Share,” would have a favorable $0.23 impact during the year ended December 31, 2021 if we were to translate prior year results at current quarter exchange rates.

Interest Rate Risk

Our fiduciary investment income is affected by changes in international and domestic short-term interest rates. We monitor our net exposure to short-term interest rates and, as appropriate, hedge our exposure with various derivative financial instruments. This activity primarily relates to brokerage funds held on behalf of clients in the U.S. and in continental Europe. A hypothetical, instantaneous parallel decrease in the year-end yield curve of 100 BPS would cause a decrease, net of derivative positions, of $64 million to each of 2022 and 2023 pretax income. A corresponding increase in the year-end yield curve of 100 BPS would cause an increase, net of derivative positions, of $64 million to each of 2022 and 2023 pre-tax income.

We have long-term debt outstanding, excluding the current portion, with a fair market value of $9.2 billion and $8.8 billion as of December 31, 2021 and December 31, 2020, respectively. The fair value was greater than the carrying value by $0.9 billion at December 31, 2021, and $1.4 billion greater than the carrying value at December 31, 2020. A hypothetical 1% increase or decrease in interest rates would change the fair value by a decrease of 8% or an increase of 9%, respectively, at December 31, 2021.

We have selected hypothetical changes in foreign currency exchange rates, interest rates, and equity market prices to illustrate the possible impact of these changes; we are not predicting market events.

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Item 8.    Financial Statements and Supplementary Data

Report of Independent Registered Public Accounting Firm

To the Shareholders and Board of Directors of Aon plc

Opinion on the Financial Statements

We have audited the accompanying consolidated statement of financial position of Aon plc (the Company) as of December 31, 2021 and 2020, the related consolidated statements of income, comprehensive income, shareholders’ equity and cash flows for each of the three years in the period ended December 31, 2021, and the related notes (collectively referred to as the “financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 18, 2022, expressed an unqualified opinion thereon.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the account or disclosure to which it relates.

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	Realizability of Deferred Tax Assets
Description of the Matter	As discussed in Note 10 “Income Taxes” of the Notes to Consolidated Financial Statements, the Company had net deferred tax assets of $365 million at December 31, 2021. Deferred tax assets are reduced by a valuation allowance if, based on the weight of all available evidence, in management’s judgment it is more likely than not that some portion, or all, of the deferred tax assets will not be realized. Conclusions on the realizability of certain net deferred tax assets involve significant management judgement including assumptions and estimates related to the amount and timing of future taxable income. Auditing the deferred tax asset calculation and the related forecast of future taxable income was especially challenging as it involved a high degree of auditor judgement around management’s assumptions and estimates.
How We Addressed the Matter in Our Audit	We obtained an understanding, evaluated the design and operating effectiveness of internal controls that address the risks of material misstatement relating to the realizability of deferred tax assets, including controls over management’s projections of future taxable income and the related assumptions. Among other audit procedures performed, we evaluated the assumptions used by the Company to develop projections of future taxable income by income tax jurisdiction and tested the completeness and accuracy of the underlying data used in the projections. For example, we inspected the growth rate used in the calculation, the estimates of the reversal of cumulative temporary differences by year and the capital and debt requirements by jurisdiction. We compared the projections of future taxable income with the actual results of prior periods, as well as management’s considerations of current industry and economic trends. Further, we involved tax subject matter professionals in the review of the information identified.

We have served as the Company’s auditor since 1986.

Chicago, Illinois

February 18, 2022

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Aon plc

Consolidated Statements of Income

	Years Ended December 31
(millions, except per share data)	2021		2020		2019
Revenue
Total revenue	$	12,193	$	11,066	$	11,013
Expenses
Compensation and benefits	6,738		5,905		6,054
Information technology	477		444		494
Premises	327		291		339
Depreciation of fixed assets	179		167		172
Amortization and impairment of intangible assets	147		246		392
Other general expense	2,235		1,232		1,393
Total operating expenses	10,103		8,285		8,844
Operating income	2,090		2,781		2,169
Interest income	11		6		8
Interest expense	(322)		(334)		(307)
Other income	152		13		—
Income before income taxes	1,931		2,466		1,870
Income tax expense	623		448		297
Net income	1,308		2,018		1,573
Less: Net income attributable to noncontrolling interests	53		49		41
Net income attributable to Aon shareholders	$	1,255	$	1,969	$	1,532
Basic net income per share attributable to Aon shareholders	$	5.59	$	8.49	$	6.42
Diluted net income per share attributable to Aon shareholders	$	5.55	$	8.45	$	6.37
Weighted average ordinary shares outstanding - basic	224.7		231.9		238.6
Weighted average ordinary shares outstanding - diluted	226.1		233.1		240.6

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Comprehensive Income

	Years Ended December 31
(millions)	2021		2020		2019
Net income	$	1,308	$	2,018	$	1,573
Less: Net income attributable to noncontrolling interests	53		49		41
Net income attributable to Aon shareholders	1,255		1,969		1,532
Other comprehensive income (loss), net of tax:
Change in fair value of financial instruments	1		13		3
Foreign currency translation adjustments	(289)		263		14
Postretirement benefit obligation	277		(101)		(141)
Total other comprehensive income (loss)	(11)		175		(124)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(1)		3		—
Total other comprehensive income (loss) attributable to Aon shareholders	(10)		172		(124)
Comprehensive income attributable to Aon shareholders	$	1,245	$	2,141	$	1,408

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Shareholders’ Equity

(millions, except per share data)	Shares	Ordinary Shares and Additional Paid-in Capital		Retained Earnings (Accumulated Deficit)		Accumulated Other Comprehensive Loss, Net of Tax		Non-controlling Interests		Total
Balance at December 31, 2018	240.1	$	5,967	$	2,093	$	(3,909)	$	68	$	4,219
Net income	—	—		1,532		—		41		1,573
Shares issued — employee stock compensation plans	2.5	(130)		(1)		—		—		(131)
Shares purchased	(10.5)	—		(1,960)		—		—		(1,960)
Share-based compensation expense	—	317		—		—		—		317
Dividends to shareholders ($1.72 per share)	—	—		(410)		—		—		(410)
Net change in fair value of financial instruments	—	—		—		3		—		3
Net foreign currency translation adjustments	—	—		—		14		—		14
Net postretirement benefit obligation	—	—		—		(141)		—		(141)
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(35)		(35)
Balance at December 31, 2019	232.1	6,154		1,254		(4,033)		74		3,449
Adoption of new accounting guidance	—	—		(6)		—		—		(6)
Balance at January 1, 2020	232.1	6,154		1,248		(4,033)		74		3,443
Net income	—	—		1,969		—		49		2,018
Shares issued — employee stock compensation plans	1.9	(154)		—		—		—		(154)
Shares purchased	(8.5)	—		(1,763)		—		—		(1,763)
Share-based compensation expense	—	317		—		—		—		317
Dividends to shareholders ($1.78 per share)	—	—		(412)		—		—		(412)
Net change in fair value of financial instruments	—	—		—		13		—		13
Net foreign currency translation adjustments	—	—		—		260		3		263
Net postretirement benefit obligation	—	—		—		(101)		—		(101)
Net purchases of shares from noncontrolling interests	—	(3)		—		—		(6)		(9)
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(32)		(32)
Balance at December 31, 2020	225.5	6,314		1,042		(3,861)		88		3,583
Net income	—	—		1,255		—		53		1,308
Shares issued — employee stock compensation plans	1.7	(129)		(1)		—		—		(130)
Shares purchased	(12.4)	—		(3,543)		—		—		(3,543)
Share-based compensation expense	—	449		—		—		—		449
Dividends to shareholders ($1.99 per share)	—	—		(447)		—		—		(447)
Net change in fair value of financial instruments	—	—		—		1		—		1
Net foreign currency translation adjustments	—	—		—		(288)		(1)		(289)
Net postretirement benefit obligation	—	—		—		277		—		277
Net purchases of shares from noncontrolling interests	—	(8)		—		—		(5)		(13)
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(38)		(38)
Balance at December 31, 2021	214.8	$	6,626	$	(1,694)	$	(3,871)	$	97	$	1,158

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Financial Position

	As of December 31
(millions, except nominal value)	2021		2020
Assets
Current assets
Cash and cash equivalents	$	544	$	884
Short-term investments	292		308
Receivables, net	3,094		3,070
Fiduciary assets	14,386		13,798
Other current assets	716		624
Total current assets	19,032		18,684
Goodwill	8,434		8,666
Intangible assets, net	492		640
Fixed assets, net	529		599
Operating lease right-of-use assets	786		911
Deferred tax assets	766		724
Prepaid pension	1,366		1,280
Other non-current assets	512		610
Total assets	$	31,917	$	32,114
Liabilities and equity
Liabilities
Current liabilities
Accounts payable and accrued liabilities	$	2,192	$	2,016
Short-term debt and current portion of long-term debt	1,164		448
Fiduciary liabilities	14,386		13,798
Other current liabilities	1,331		1,171
Total current liabilities	19,073		17,433
Long-term debt	8,228		7,281
Non-current operating lease liabilities	772		897
Deferred tax liabilities	401		262
Pension, other postretirement, and postemployment liabilities	1,375		1,763
Other non-current liabilities	910		895
Total liabilities	30,759		28,531
Equity
Ordinary shares - $0.01 nominal value     Authorized: 500.0 shares (issued: 2021 - 214.8; 2020 - 225.5)	2		2
Additional paid-in capital	6,624		6,312
Retained earnings (accumulated deficit)	(1,694)		1,042
Accumulated other comprehensive loss	(3,871)		(3,861)
Total Aon shareholders' equity	1,061		3,495
Noncontrolling interests	97		88
Total equity	1,158		3,583
Total liabilities and equity	$	31,917	$	32,114

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Cash Flows

	Years Ended December 31
(millions)	2021		2020 (As Revised)		2019 (As Revised)
Cash flows from operating activities
Net income	$	1,308	$	2,018	$	1,573
Adjustments to reconcile net income to cash provided by operating activities:
Gain from sales of businesses and investments	(142)		(25)		(13)
Depreciation of fixed assets	179		167		172
Amortization and impairment of intangible assets	147		246		392
Share-based compensation expense	449		312		317
Deferred income taxes	11		9		(36)
Change in assets and liabilities:
Receivables, net	(119)		108		(371)
Accounts payable and accrued liabilities	264		186		(28)
Current income taxes	200		(17)		(20)
Pension, other postretirement and postemployment liabilities	(119)		(141)		(156)
Other assets and liabilities	4		(80)		5
Cash provided by operating activities	2,182		2,783		1,835
Cash flows from investing activities
Proceeds from investments	58		64		61
Payments for investments	(91)		(97)		(113)
Net sales (purchases) of short-term investments - non fiduciary	15		(167)		35
Acquisition of businesses, net of cash and funds held on behalf of clients	(14)		(368)		(39)
Sale of businesses, net of cash and funds held on behalf of clients	218		30		52
Capital expenditures	(137)		(141)		(225)
Cash provided by (used for) investing activities	49		(679)		(229)
Cash flows from financing activities
Share repurchase	(3,543)		(1,763)		(1,960)
Issuance of shares for employee benefit plans	(130)		(149)		(131)
Issuance of debt	5,973		4,153		6,052
Repayment of debt	(4,220)		(3,882)		(4,941)
Increase in fiduciary liabilities, net of fiduciary receivables	568		316		1,246
Cash dividends to shareholders	(447)		(412)		(410)
Noncontrolling interests and other financing activities	(125)		(35)		(103)
Cash used for financing activities	(1,924)		(1,772)		(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(235)		297		63
Net increase in cash and cash equivalents and funds held on behalf of clients	72		629		1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	6,573		5,944		4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	$	6,645	$	6,573	$	5,944
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	$	544	$	884	$	790
Funds held on behalf of clients	6,101		5,689		5,154
Total cash and cash equivalents and funds held on behalf of clients	$	6,645	$	6,573	$	5,944
Supplemental disclosures:
Interest paid	$	328	$	326	$	289
Income taxes paid, net of refunds	$	412	$	455	$	353

See accompanying Notes to Consolidated Financial Statements.

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Notes to Consolidated Financial Statements

1.    Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. The Consolidated Financial Statements include the accounts of Aon plc and all of its controlled subsidiaries (“Aon” or the “Company”). Intercompany accounts and transactions have been eliminated. The Consolidated Financial Statements include, in the opinion of management, all adjustments (consisting of normal recurring adjustments and reclassifications) necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows for all periods presented.

References in this report to “Aon,” the “Company,” “we,” “us,” or “our” for time periods prior to April 1, 2020 refer to Aon Global Limited. References in the Financial Statements to “Aon,” the “Company,” “we,” “us,” or “our” for time periods on or after April 1, 2020, refer to Aon plc.

Reclassification

Certain amounts in the prior year's Consolidated Financial Statements have been reclassified to conform to the current year’s presentation. For the years ended December 31, 2020 and December 31, 2019, there was $1 million of income and $1 million of loss, respectively, including the related tax effect, from discontinued operations recognized in Net Income from discontinued operations in the Consolidated Statements of Income and Consolidated Statements of Cash Flows. These amounts are now included in Other income in the Consolidated Statements of Income and Other assets and liabilities in the Consolidated Statements of Cash Flows for the years ended December 31, 2020 and December 31, 2019. There was no impact to the effective tax rate on Net income or earnings per share in either period.

Additionally, for the years ended December 31, 2020 and December 31, 2019, a cash outflow of $127 million and a cash inflow of $3 million, respectively, was classified as an adjustment to Net income from Restructuring reserves in the Consolidated Statements of Cash Flows. These amounts are now included in Other assets and liabilities in the Consolidated Statements of Cash Flows for the years ended December 31, 2020 and December 31, 2019. There was no impact on Cash provided by operating activities.

Disaggregation of Revenue

In 2021, the Company announced steps to further accelerate its Aon United strategy, which now includes four solution lines: Commercial Risk Solutions, Reinsurance Solutions, Health Solutions, and Wealth Solutions. Disaggregation of revenue by the new solution line’s structure is reflected in Note 3 “Revenue from Contracts with Customers”, where prior period amounts have been reclassified to conform to the current periods’ presentation. The changes in the solution line structure affect only the manner in which the Company's revenue results for the Company’s principal service lines were previously reported and have no impact on the Company's previously reported Consolidated Financial Statements, results of operations, or total organic revenue growth. Refer to Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for more information about the changes in the presentation of our principal service line reporting. The Company continues to operate as one segment that includes all of the Company’s operations, refer to Note 16 “Segment Information” for further information.

Use of Estimates

The preparation of the accompanying Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of reserves and expenses. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management believes its estimates to be reasonable given the current facts available. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, foreign currency exchange rate movements, and the COVID-19 pandemic increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment would, if applicable, be reflected in the Consolidated Financial Statements in future periods.

Revision of Previously Issued Financial Statements

During the fourth quarter of 2021, the Company identified and corrected an immaterial presentation error related to funds held on behalf of clients in the Consolidated Statements of Cash Flows.

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Based on an analysis of quantitative and qualitative factors in accordance with SEC Staff Accounting Bulletins 99 “Materiality” and 108 “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements”, the Company concluded that these errors were immaterial, individually and in the aggregate, to the Consolidated Statements of Cash Flows as presented in the Company’s quarterly and annual financial statements previously filed in the Company’s Quarterly Reports on Form 10-Q and Annual Reports on Form 10-K. There was no impact to the Consolidated Statements of Income, Statements of Comprehensive Income, Statements of Financial Position, or Statements of Shareholders’ Equity for any period presented.

In preparing the Company’s Consolidated Statement of Cash Flows for the year ended December 31, 2021, the Company made appropriate revisions to its Consolidated Statements of Cash Flows for historical periods. Such changes are reflected for the years ended December 31, 2020 and 2019, included in these financial statements, and will also be reflected in the historical periods included in the Company’s subsequent quarterly and annual consolidated financial statements.

The impact to the Consolidated Statements of Cash Flows previously filed in Annual Reports on Form 10-K is as follows (in millions):

	Year Ended December 31, 2020						Year Ended December 31, 2019
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	2,783	$	—	$	2,783	$	1,835	$	—	$	1,835
Cash used for investing activities	(679)		—		(679)		(229)		—		(229)
Cash provided by (used for) financing activities	(2,088)		316		(1,772)		(1,493)		1,246		(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	78		219		297		21		42		63
Net increase in cash and cash equivalents and funds held on behalf of clients	94		535		629		134		1,288		1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	790		5,154		5,944		656		3,866		4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	$	884	$	5,689	$	6,573	$	790	$	5,154	$	5,944

The impact to the Consolidated Statements of Cash Flows previously filed in unaudited Quarterly Reports on Form 10-Q is as follows (in millions):

	Three Months Ended March 31, 2021						Six Months Ended June 30, 2021						Nine Months Ended September 30, 2021
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	561	$	—	$	561	$	1,345	$	—	$	1,345	$	1,251	$	—	$	1,251
Cash provided by (used for) investing activities	102		—		102		(27)		—		(27)		(116)		—		(116)
Cash provided by (used for) financing activities	(709)		28		(681)		(1,122)		386		(736)		(1,380)		786		(594)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(16)		(18)		(34)		11		18		29		(30)		(63)		(93)
Net increase (decrease) in cash and cash equivalents and funds held on behalf of clients	(62)		10		(52)		207		404		611		(275)		723		448
Cash and cash equivalents and funds held on behalf of clients at beginning of year	884		5,689		6,573		884		5,689		6,573		884		5,689		6,573
Cash and cash equivalents and funds held on behalf of clients at end of year	$	822	$	5,699	$	6,521	$	1,091	$	6,093	$	7,184	$	609	$	6,412	$	7,021

2.    Summary of Significant Accounting Principles and Practices

Revenue Recognition

The Company generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services provided to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several

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factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which the Company acts. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services and (2) fees and commissions for administrative and other services provided to or on behalf of insurers. In Aon’s capacity as an insurance and reinsurance broker, the service promised to the customer is placement of an effective insurance or reinsurance policy, respectively. At the completion of the insurance or reinsurance policy placement process once coverage is effective, the customer has obtained control over the services promised by the Company. Judgment is not typically required when assessing whether the coverage is effective. Fees from clients for advice and consulting services are dependent on the extent and value of the services provided. Payment terms for the Company’s principal service lines are discussed below; the Company believes these terms are consistent with current industry practices. Significant financing components are typically not present in Aon’s arrangements.

The Company recognizes revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, the Company assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, the Company allocates consideration based on their relative fair values.

Costs incurred by the Company in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

The Company has elected to apply practical expedients to not disclose the revenue related to unsatisfied performance obligations if (1) the contract has an original duration of 1 year or less, (2) the Company has recognized revenue for the amount in which it has the right to bill, and (3) the variable consideration is allocated entirely to an unsatisfied performance obligation which is recognized as a series of distinct goods or services that form a single performance obligation.

Disaggregation of Revenue

The following is a description of principal service lines from which the Company generates its revenue:

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units transferred and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly, over the term of the arrangement in installments based on deposit or minimum premiums for most treaty reinsurance arrangements.

Health Solutions includes consulting and brokerage, Human Capital, and voluntary benefits and enrollment solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services using input or output measures, including units delivered or time elapsed, to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue from health care exchange arrangements is typically recognized upon successful enrollment

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of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

Wealth Solutions includes retirement consulting and pension administration, as well as investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services, or for certain arrangements, at a point in time upon completion of the services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Share-based Compensation Expense

Share-based payments to employees, including grants of RSUs and PSAs, are measured based on grant date fair value. For purposes of measuring share-based compensation expense, the Company considered whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2021, 2020, or 2019. The Company recognizes compensation expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs materially from original estimates.

Pension and Other Postretirement Benefits

The Company records net periodic cost relating to its pension and other postretirement benefit plans based on calculations that include various actuarial assumptions, including discount rates, assumed rates of return on plan assets, inflation rates, mortality rates, compensation increases, and turnover rates. The Company reviews its actuarial assumptions on an annual basis and modifies these assumptions based on current rates and trends. The effects of gains, losses, and prior service costs and credits are amortized over future service periods or future estimated lives if the plans are frozen as reflected in Other income within the Consolidated Statements of Income. The funded status of each plan, calculated as the fair value of plan assets less the benefit obligation, is reflected in the Company’s Consolidated Statements of Financial Position using a December 31 measurement date.

Earnings per Share

Basic earnings per share is computed by dividing net income available to ordinary shareholders by the weighted-average number of ordinary shares outstanding, including participating securities, which consist of unvested share awards with non-forfeitable rights to dividends. Diluted earnings per share is computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding, which have been adjusted for the dilutive effect of potentially issuable ordinary shares, including certain contingently issuable shares. The diluted earnings per share calculation reflects the more dilutive effect of either (1) the two-class method that assumes that the participating securities have not been exercised, or (2) the treasury stock method.

Potentially issuable shares are not included in the computation of diluted earnings per share if their inclusion would be antidilutive.

Cash and Cash Equivalents and Short-term Investments

Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments consist of money market funds. The estimated fair value of Cash and cash equivalents and Short-term investments approximates their carrying values.

At December 31, 2021, Cash and cash equivalents and Short-term investments totaled $836 million compared to $1,192 million at December 31, 2020, a decrease of $356 million. Of the total balance, $160 million and $102 million was restricted as to its use at December 31, 2021 and 2020, respectively. Included within Short-term investments as of December 31, 2021 and 2020 balances, respectively, were £84.3 million ($112.8 million at December 31, 2021 exchanges rates) and £44.4 million ($60.2

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million at December 31, 2020 exchange rates) of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator. During 2021, following discussions with the FCA, and to take into consideration the potential future effects from market volatility due to COVID-19, the Company changed the basis of calculating its liquidity requirement and increased the amount of funds held by £34.3 million ($45.9 million at December 31, 2021 exchange rates).

Fiduciary Assets and Liabilities

In its capacity as an insurance agent and broker, Aon collects premiums from insureds and, after deducting its commission, remits the premiums to the respective insurers. Aon also collects claims or refunds from insurers on behalf of insureds. Uncollected premiums from insureds and uncollected claims or refunds from insurers are recorded as Fiduciary assets in the Company’s Consolidated Statements of Financial Position. Unremitted insurance premiums and claims are held in a fiduciary capacity and the obligation to remit these funds is recorded as Fiduciary liabilities in the Consolidated Statements of Financial Position.

Funds held on behalf of clients represent fiduciary assets held by Aon for premiums collected from insureds but not yet remitted to insurance companies and claims collected from insurance companies but not yet remitted to insureds of $6.1 billion and $5.7 billion at December 31, 2021 and 2020, respectively. Fiduciary receivables were $8.3 billion and $8.1 billion at December 31, 2021 and 2020, respectively. These funds and a corresponding liability are included in Fiduciary assets and Fiduciary liabilities, respectively, in the accompanying Consolidated Statements of Financial Position.

Allowance for Doubtful Accounts

The Company’s estimate for allowance for credit losses with respect to receivables is based on a combination of factors, including evaluation of forward-looking information, historical write-offs, aging of balances, and other qualitative and quantitative analyses. Receivables, net included an allowance for doubtful accounts of $90 million and $98 million at December 31, 2021 and 2020, respectively.

Fixed Assets

Fixed assets are stated at cost, less accumulated depreciation. Included in this category are certain capitalized costs incurred during the application development stage related to directly obtaining, developing, or enhancing internal use software. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which are generally as follows:

Asset Description	Estimated Useful Life
Software	Lesser of the life of an associated license, or 4 to 7 years
Leasehold improvements	Lesser of estimated useful life or lease term, not to exceed 10 years
Furniture, fixtures and equipment	4 to 10 years
Computer equipment	4 to 6 years
Buildings	35 years
Automobiles	6 years

Goodwill and Intangible Assets

Goodwill represents the excess of acquisition cost over the fair value of the net assets acquired in the acquisition of a business. Goodwill is allocated to applicable reporting units. Upon disposition of a business entity, goodwill is allocated to the disposed entity based on the fair value of that entity compared to the fair value of the reporting unit in which it was included. Goodwill is not amortized, but instead is tested for impairment at least annually. The goodwill impairment test is performed at the reporting unit level. The Company may initially perform a qualitative analysis to determine if it is more likely than not that the goodwill balance is impaired. If a qualitative assessment is not performed or if a determination is made that it is not more likely than not that their value of the reporting unit exceeds its carrying amount, then the Company will perform a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit. Any resulting difference will be a charge to Amortization and impairment of intangible assets in the Consolidated Statements of Income in the period in which the determination is made. Fair value is determined using a combination of present value techniques and market prices of comparable businesses.

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We classify our intangible assets acquired as either tradenames, customer-related and contract-based, or technology and other. Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Derivatives

Derivative instruments are recognized in the Consolidated Statements of Financial Position at fair value. Where the Company has entered into master netting agreements with counterparties, the derivative positions are netted by counterparties and are reported accordingly in other assets or other liabilities. Changes in the fair value of derivative instruments are recognized in earnings each period, unless the derivative is designated and qualifies as a cash flow or net investment hedge.

The Company has historically designated the following hedging relationships for certain transactions: (1) a hedge of the change in fair value of a recognized asset or liability or firm commitment (“fair value hedge”), (2) a hedge of the variability in cash flows from a recognized variable-rate asset or liability or forecasted transaction (“cash flow hedge”), and (3) a hedge of the net investment in a foreign operation (“net investment hedge”).

In order for a derivative to qualify for hedge accounting, the derivative must be formally designated as a fair value, cash flow, or a net investment hedge by documenting the relationship between the derivative and the hedged item. The documentation must include a description of the hedging instrument, the hedged item, the risk being hedged, Aon’s risk management objective and strategy for undertaking the hedge, and the method for assessing the effectiveness of the hedge. Additionally, the hedge relationship must be expected to be highly effective at offsetting changes in either the fair value or cash flows of the hedged item at both the inception of the hedge and on an ongoing basis. Aon assesses the ongoing effectiveness of its hedges quarterly or more frequently if facts and circumstances require.

For a derivative designated as a fair value hedging instrument, the gain or loss is recognized in earnings in the period of change together with the offsetting loss or gain on the hedged item attributable to the risk being hedged. The effect is to reflect in earnings the extent to which the hedge is not effective in achieving offsetting changes in fair value. For a cash flow hedge that qualifies for hedge accounting, the change in fair value of a hedging instrument is recognized in Accumulated Other Comprehensive Income and subsequently reclassified to earnings in the same period the hedged item impacts earnings. For a net investment hedge, the change in fair value of the hedging instrument is recognized in Accumulate Other Comprehensive Income as part of the cumulative translation adjustment.

Changes in the fair value of a derivative that is not designated as part of a hedging relationship (commonly referred to as an “economic hedge”) are recorded in Other income in the Consolidated Statements of Income in the period of change.

The Company discontinues hedge accounting prospectively when (1) the derivative expires or is sold, terminated, or exercised, (2) the qualifying criteria are no longer met, or (3) management removes the designation of the hedging relationship.

Foreign Currency

Certain of the Company’s non-U.S. operations use their respective local currency as their functional currency. These operations that do not have the U.S. dollar as their functional currency translate their financial statements at the current rates of exchange in effect at the balance sheet date and revenues and expenses using rates that approximate those in effect during the period. The resulting translation adjustments are included in Net foreign currency translation adjustments within the Consolidated Statements of Shareholders’ Equity. Further, gains and losses from the remeasurement of monetary assets and liabilities that are denominated in a non-functional currency of that entity are included in Other income within the Consolidated Statements of Income.

Income Taxes

Deferred income taxes are recognized for the effect of temporary differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted marginal tax rates and laws that are currently in effect. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period when the rate change is enacted.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences,

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future taxable income exclusive of reversing temporary differences and carry-forwards, taxable income in carry-back years, and tax planning strategies that are both prudent and feasible.

The Company recognizes the effect of income tax positions only if sustaining those positions is more likely than not. Tax positions that meet the more likely than not recognition threshold but are not highly certain are initially and subsequently measured based on the largest amount of benefit that is greater than 50% likely of being realized upon settlement with the taxing authority. Only information that is available at the reporting date is considered in the Company’s recognition and measurement analysis, and events or changes in facts and circumstances are accounted for in the period in which the event or change in circumstance occurs.

The Company records penalties and interest related to unrecognized tax benefits in Income taxes in the Company’s Consolidated Statements of Income.

Leases

The Company leases office facilities, equipment, and automobiles under operating and finance leases. The Company’s lease obligations are primarily for the use of office facilities. The Company evaluates if a leasing arrangement exists upon inception of a contract. A contract contains a lease if the contract conveys the right to control the use of identified tangible assets for a period of time in exchange for consideration. Identified property, plant, or equipment may include a physically distinct portion of a larger asset, or a portion of an asset that represents substantially all of the capacity of the asset but is not physically distinct. The Company assesses whether a contract implicitly contains the right to control the use of a tangible asset that is not already owned. In addition, the Company subleases certain real estate properties to third parties, which are classified as operating leases.

The Company’s leases expire at various dates and may contain renewal, expansion or termination options. The exercise of lease renewal and expansion options are typically at the Company’s sole discretion and are only included in the determination of the lease term if the Company is reasonably certain to exercise the option. In addition, the Company’s lease agreements typically do not contain any material residual value guarantees or restrictive covenants.

ROU assets and lease liabilities are based on the present value of the minimum lease payments over the lease term. The Company has elected the practical expedient related to lease and non-lease components, as an accounting policy election for all asset classes, which allows a lessee to not separate non-lease components from lease components and instead account for consideration received in a contract as a single lease component.

The Company made a policy election to not recognize ROU assets and lease liabilities that arise from leases with an initial term of twelve months or less in the Consolidated Statements of Financial Position. However, the Company recognized these lease payments in the Consolidated Statements of Income on a straight-line basis over the lease term and variable lease payments in the period in which the expense was incurred. The Company chose to apply this accounting policy across all classes of underlying assets.

A portion of the Company’s lease agreements include variable lease payments that are not recorded in the initial measurement of the lease liability and ROU asset balances. For real estate arrangements, base rental payments may be escalated according to annual changes in the CPI or other indices. The escalated rental payments based on the estimated CPI at the lease commencement date are included within minimum rental payments; however, changes in CPI are considered variable in nature and are recognized as variable lease costs in the period in which the obligation is incurred. Additionally, real estate lease agreements may include other variable payments related to operating expenses charged by the landlord based on actual expenditures. Information technology equipment agreements may include variable payments based on usage of the equipment. These expenses are also recognized as variable lease costs in the period in which the expense is incurred.

The Company utilizes discount rates to determine the present value of the lease payments based on information available at the commencement date of the lease. As the rate implicit in each lease is not typically readily available, the Company uses an incremental borrowing rate based on factors such as the lease term and the economic environment where the lease exists to determine the appropriate present value of future lease payments. When determining the incremental borrowing rate, the Company considers the rate of interest it would pay on a secured borrowing in an amount equal to the lease payments for the underlying asset under similar terms.

Operating leases are included in Operating lease ROU assets, Other current liabilities, and Non-current operating lease liabilities in the Consolidated Statements of Financial Position. Finance leases are included in Other non-current assets, Other current liabilities, and Other non-current liabilities in the Consolidated Statements of Financial Position.

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Principles of Consolidation

The accompanying Consolidated Financial Statements include the accounts of Aon plc and those entities in which the Company has a controlling financial interest. To determine if Aon holds a controlling financial interest in an entity, the Company first evaluates if it is required to apply the VIE model to the entity, otherwise, the entity is evaluated under the voting interest model. Where Aon holds rights that give it the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, combined with a variable interest that gives the right to receive potentially significant benefits or the obligation to absorb potentially significant losses, the Company has a controlling financial interest in that VIE. The Company does not consolidate the VIEs and Aon’s interest in VIEs as of December 31, 2021 was insignificant. Aon holds a controlling financial interest in entities that are not VIEs where it, directly or indirectly, holds more than 50% of the voting rights or where it exercises control through substantive participating rights or as a general partner.

New Accounting Pronouncements

Adoption of New Accounting Standards

Contract Assets and Contract Liabilities Acquired in a Business Combination

In October 2021, FASB issued new accounting guidance related to the accounting for contract assets and contract liabilities from contracts with customers acquired in a business combination. The new guidance improves the accounting for acquired revenue contracts with customers in a business combination by addressing diversity in practice and inconsistency. The new guidance requires an entity to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with the current accounting standard on revenue from contracts with customers, ASC 606. The new guidance is effective for Aon in the first quarter of 2023, with early adoption permitted. The Company elected to early adopt this guidance in the fourth quarter of 2021. The Company adopted the new guidance on a prospective basis while applying the amendments to all business combinations that occurred during 2021 as required by the new guidance. The early adoption of the new guidance did not have a material impact on the Consolidated Financial Statements.

3.    Revenue from Contracts with Customers

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions). Prior year amounts from the Consolidated Financial Statements have been reclassified to conform to the current year’s presentation. Refer to Note 1 “Basis of Presentation” for further information regarding the changes to the Company’s principal service lines.

	Years Ended December 31
	2021		2020		2019
Commercial Risk Solutions	$	6,635	$	5,861	$	5,857
Reinsurance Solutions	1,997		1,814		1,686
Health Solutions	2,154		2,067		2,104
Wealth Solutions	1,426		1,341		1,380
Elimination	(19)		(17)		(14)
Total revenue	$	12,193	$	11,066	$	11,013

Consolidated revenue from contracts with customers by geographic area, which is attributed on the basis of where the services are performed, is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	5,459	$	5,032	$	5,016
Americas other than U.S.	1,027		911		919
U.K.	1,681		1,579		1,502
Ireland	127		84		75
Europe, Middle East, & Africa other than U.K. and Ireland	2,565		2,236		2,263
Asia Pacific	1,334		1,224		1,238
Total revenue	$	12,193	$	11,066	$	11,013

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Contract Costs

Changes in the net carrying amount of costs to fulfill contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	339	$	335
Additions	1,504		1,360
Amortization	(1,478)		(1,360)
Impairment	—		—
Foreign currency translation and other	(4)		4
Balance at end of period	$	361	$	339

Changes in the net carrying amount of costs to obtain contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	184	$	171
Additions	59		61
Amortization	(48)		(47)
Impairment	—		—
Foreign currency translation and other	(16)		(1)
Balance at end of period	$	179	$	184

4.    Other Financial Data

Consolidated Statements of Income Information

Other Income

The components of Other income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Foreign currency remeasurement	$	26	$	(12)	$	9
Gain from disposals of business	142		25		13
Pension and other postretirement	21		13		9
Equity earnings	8		4		4
Extinguishment of debt	—		(7)		—
Financial instruments	(45)		(10)		(35)
Total	$	152	$	13	$	—

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Consolidated Statements of Financial Position Information

Allowance for Doubtful Accounts

Changes in the net carrying amount of allowance for doubtful accounts are as follows (in millions):

	2021		2020		2019
Balance at beginning of period	$	98	$	70	$	62
Adoption of new accounting guidance (1)	—		7		—
Adjusted balance at beginning of period	98		77		62
Provision	26		29		27
Accounts written off, net of recoveries	(37)		(6)		(19)
Foreign currency translation and other	3		(2)		—
Balance at end of period	$	90	$	98	$	70

(1) The adoption of the new accounting standard on the measurement of credit losses on January 1, 2020 resulted in addition to the Allowance for doubtful accounts of $7 million. After tax impacts, this resulted in a $6 million decrease to Retained earnings. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” for further information.

Other Current Assets

The components of Other current assets are as follows (in millions):

As of December 31	2021		2020
Costs to fulfill contracts with customers(1)	$	361	$	339
Taxes receivable	53		95
Prepaid expenses	137		111
Other	165		79
Total	$	716	$	624

(1)Refer to Note 3 “Revenue from Contracts with Customers” for further information.

Fixed Assets, net

The components of Fixed assets, net are as follows (in millions):

As of December 31	2021		2020
Software	$	797	$	808
Leasehold improvements	425		375
Computer equipment	268		249
Furniture, fixtures and equipment	279		246
Construction in progress	45		155
Other	33		34
Fixed assets, gross	1,847		1,867
Less: Accumulated depreciation	1,318		1,268
Fixed assets, net	$	529	$	599

Depreciation expense, which includes software amortization, was $179 million, $167 million, and $172 million for the years ended December 31, 2021, 2020, and 2019, respectively.

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Other Non-current Assets

The components of Other non-current assets are as follows (in millions):

As of December 31	2021		2020
Costs to obtain contracts with customers (1)	$	179	$	184
Investments	64		74
Leases (2)	63		89
Taxes receivable	95		125
Other	111		138
Total	$	512	$	610

(1)    Refer to Note 3 “Revenue from Contracts with Customers” for further information.

(2) Refer to Note 8 “Lease Commitments” for further information.

Other Current Liabilities

The components of Other current liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred revenue (1)	$	321	$	296
Taxes payable	149		80
Leases (2)	213		234
Other	648		561
Total	$	1,331	$	1,171

(1)$553 million and $454 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2021 and December 31, 2020, respectively.

(2)Refer to Note 8 “Lease Commitments” for further information.

Other Non-current Liabilities

The components of Other non-current liabilities are as follows (in millions):

As of December 31	2021		2020
Taxes payable (1)	$	609	$	561
Leases (2)	46		65
Compensation and benefits	58		53
Deferred revenue	70		76
Other	127		140
Total	$	910	$	895

(1)Includes $145 million for the non-current portion of the transition tax as of December 31, 2021 and December 31, 2020. Refer to Note 9 “Income Taxes” for further information on the transition tax.

(2)Refer to Note 8 “Lease Commitments” for further information.

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5.    Acquisitions and Dispositions of Businesses

Completed Acquisitions

The Company completed two acquisitions during the year ended December 31, 2021 and six acquisitions during the year ended December 31, 2020. The following table includes the preliminary fair values of consideration transferred, assets acquired, and liabilities assumed as a result of the Company’s acquisitions (in millions):

	Year Ended December 31, 2021
Consideration transferred
Cash	$	27
Deferred, contingent, and other consideration	17
Aggregate consideration transferred	$	44
Assets acquired
Goodwill	17
Other intangible assets	13
Other assets (1)	26
Total assets acquired	56
Liabilities assumed
Total liabilities assumed	12
Net assets acquired	$	44

(1)     In the year ended December 31, 2021, cash and cash equivalents of $12 million and funds held on behalf of client of $1 million were acquired.

Intangible assets acquired include customer-related and contract-based assets. The intangible assets acquired as part of business acquisitions in 2021 had a weighted average useful economic life of 9 years. Acquisition related costs for completed acquisitions incurred and recognized within Other general expense for the year ended December 31, 2021 were insignificant.

The results of operations of these acquisitions are included in the Consolidated Financial Statements as of the respective acquisition dates. The Company’s results of operations would not have been materially different if these acquisitions had been reported from the beginning of the period in which they were acquired.

2021 Acquisitions

On December 22, 2021, the Company completed the transaction to acquire 100% share capital of For Welfare S.r.l, a company focused on bancassurance programs in Italy.

On September 1, 2021, the Company completed the transaction to acquire 51% of Aon India Insurance Brokers Limited (formerly known as Anviti Insurance Brokers Private Limited). Prior to the acquisition date, the Company accounted for its 49% interest in Anviti as an equity-method investment. The acquisition-date fair value of the previous equity interest was $15 million and is included in the measurement of consideration transferred. There was no significant impact as a result of remeasuring the carrying value of the Company’s prior equity interest in Anviti held before the business combination.

2020 Acquisitions

On April 6, 2020, the Company completed the acquisition of 100% share capital of Farmington Administrative Services LLC, a U.S.-based national provider of enrollment solutions and voluntary benefits, and certain assets of other Farmington companies.

On January 31, 2020, the Company completed the acquisition of 100% share capital of Cytelligence Inc., a Canadian-based cyber security firm that provides incident response advisory, digital forensic expertise, security consulting services, and cyber security training for employees to help organizations respond to cyber security threats and strengthen their security position.

On January 3, 2020, the Company completed the acquisition of 100% share capital of CoverWallet, Inc., a U.S.-based digital insurance platform for small- and medium-sized businesses.

On January 1, 2020, the Company completed the acquisition of 100% share capital of TRIUM GmbH Insurance Broker, an insurance broker based in Germany.

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On January 1, 2020, the Company completed the acquisition of 100% share capital of Assimedia SA, an insurance broker based in Switzerland.

On January 1, 2020, the Company completed the acquisition of 100% share capital of Apollo Conseil et Courtage, an insurance broker based in France.

Completed Dispositions

The Company completed six dispositions during the year ended December 31, 2021, including the sale of Aon’s Retiree Health ExchangeTM business. The Company completed one disposition during the year ended December 31, 2020 and eight dispositions during the year ended December 31, 2019.

The pretax gains recognized related to dispositions were $142 million, $25 million, and $13 million for the years ended December 31, 2021, December 31, 2020 and December 31, 2019, respectively. Gains recognized as a result of a disposition are included in Other income in the Consolidated Statements of Income. The pretax losses recognized in the Consolidated Statements of Income related to these dispositions were insignificant for the years ended December 31, 2021, December 31, 2020 and December 31, 2019, respectively.

Other Significant Activity

On March 9, 2020, Aon and WTW, an Irish public limited company, entered into a business combination agreement (the “Business Combination Agreement”) with respect to a combination of the parties (the “Combination”). On July 26, 2021, Aon and WTW mutually agreed to terminate the Business Combination Agreement, (the “Termination Agreement”). Aon Corporation paid a $1 billion termination fee pursuant to the Termination Agreement. Refer to “Termination of Business Combination Agreement” within Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for further information.

6.    Goodwill and Other Intangible Assets

The changes in the net carrying amount of goodwill for the years ended December 31, 2021 and 2020, respectively, are as follows (in millions):

Balance as of January 1, 2020	$	8,165
Goodwill related to current year acquisitions	314
Goodwill related to disposals	(3)
Foreign currency translation and other	190
Balance as of December 31, 2020	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434

Other intangible assets by asset class are as follows (in millions):

As of December 31	2021						2020
	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
Customer-related and contract-based	$	2,289	$	1,848	$	441	$	2,337	$	1,775	$	562
Technology and other	407		357		50		435		358		77
Tradenames (1)	14		13		1		14		13		1
Total	$	2,710	$	2,218	$	492	$	2,786	$	2,146	$	640

(1)In 2020, Aon wrote off $1.0 billion of fully amortized tradenames, including the Hewitt and Benfield tradenames. The company no longer expects to receive economic benefits from these tradenames.

Amortization expense and impairment charges from finite lived intangible assets were $147 million, $246 million, and $392 million for the years ended December 31, 2021, 2020, and 2019, respectively.

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The estimated future amortization for finite-lived intangible assets as of December 31, 2021 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2022	$	100
2023	89
2024	72
2025	59
2026	37
Thereafter	135
Total	$	492

7.    Debt

The following is a summary of outstanding debt (in millions):

As of December 31	2021		2020
Commercial paper	$	665	$	—
2.80% Senior Notes due March 2021 (1)	—		400
2.20% Senior Notes due November 2022 (2)	499		498
4.00% Senior Notes due November 2023	349		349
3.50% Senior Notes due June 2024	598		597
3.875% Senior Notes due December 2025	748		747
2.875% Senior Notes due May 2026 (EUR 500M)	563		606
8.205% Junior Subordinated Notes due January 2027	521		521
4.50% Senior Notes due December 2028	347		347
3.75% Senior Notes due May 2029	745		744
2.80% Senior Notes due May 2030	993		992
2.05% Senior Notes due August 2031	396		—
2.60% Senior Notes due December 2031	496		—
6.25% Senior Notes due September 2040	296		296
4.25% Senior Notes due December 2042	201		200
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	544		544
4.75% Senior Notes due May 2045	593		593
2.90% Senior Notes due August 2051	591		—
Other	—		48
Total debt	9,392		7,729
Less: Short-term debt and current portion of long-term debt	1,164		448
Total long-term debt	$	8,228	$	7,281

(1)The 2.80% Senior Notes due March 2021 were repaid in full on February 16, 2021.

(2)The 2.20% Senior Notes due November 2021 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2021.

Notes

On December 2, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales, both wholly owned subsidiaries of the company, co-issued $500 million aggregate principal amount of 2.60% Senior Notes set to mature on December 2, 2031. The Company intends to use the net proceeds of the offering for general corporate purposes.

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On August 23, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales, both wholly owned subsidiaries of the Company, co-issued $400 million 2.05% Senior Notes due August 2031 and $600 million of 2.90% Senior Notes due August 2051. The Company intends to use the net proceeds of the offering for general corporate purposes.

On January 13, 2021, Aon Global Limited, a limited company organized under the laws of England and Wales and a wholly owned subsidiary of Aon plc, issued an irrevocable notice of redemption to holders of its 2.80% Senior Notes for the redemption of all $400 million outstanding aggregate principal amount of the notes, which were set to mature in March 2021 and classified as Short-term debt and current portion of long-term debt as of December 31, 2020. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

On May 29, 2020, Aon Corporation, a Delaware corporation and a wholly owned subsidiary of Aon Corporation, issued an irrevocable notice of redemption to holders of its 5.00% Senior Notes, which were set to mature on September 30, 2020, for the redemption of all $600 million outstanding aggregate principal amount of the notes. The redemption date was on June 30, 2020 and resulted in a loss of $7 million due to extinguishment.

On May 12, 2020, Aon Corporation issued $1 billion 2.80% Senior Notes due May 2030. Aon Corporation used a portion of the net proceeds on June 30, 2020 to repay its outstanding 5.00% Senior Notes, which were set to mature on September 30, 2020. The Company used the remainder to repay other borrowings and for general corporate purposes.

Each of the notes issued by Aon Corporation is fully and unconditionally guaranteed by Aon Global Limited, Aon plc, and Aon Global Holding plc. Each of the notes issued by Aon Global Limited is fully and unconditionally guaranteed by Aon plc, Aon Global Holdings plc, and Aon Corporation. All guarantees of Aon plc and Aon Global Limited of the Co-Issued Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the Co-Issuers. Refer to “Guarantee of Registered Securities” within Part II Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for further information regarding guarantees of outstanding debt securities. Each of the notes described and identified in the table above contains customary representations, warranties, and covenants, and the Company was in compliance with all such covenants as of December 31, 2021.

Repayments of total debt as of December 31, 2021 are as follows (in millions):

2022	$	1,165
2023	350
2024	600
2025	750
2026	566
Thereafter	6,077
Total Repayments	9,508
Unamortized discounts, premiums, and debt issuance costs	(116)
Total Debt	$	9,392

Revolving Credit Facilities

As of December 31, 2021, Aon plc had two primary committed credit facilities outstanding: its $1.0 billion multi-currency U.S. credit facility expiring in September 2026 and its $750 million multi-currency U.S. credit facility expiring in October 2023. In aggregate, these two facilities provide $1.75 billion in available credit. The $1.0 billion credit facility was entered into on September 28, 2021 and replaced the $900 million credit facility, which was scheduled to mature on February 2, 2022.

Each of these primary committed credit facilities includes customary representations, warranties, and covenants, including financial covenants that require Aon to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, in each case, tested quarterly. At December 31, 2021, Aon did not have borrowings under either of these primary committed credit facilities, and was in compliance with the financial covenants and all other covenants contained therein during the rolling year ended December 31, 2021.

Commercial Paper

Aon Corporation has established a U.S. commercial paper program (the “U.S. Program”) and Aon Global Holdings plc has established a European multi-currency commercial paper program (the “European Program” and, together with the U.S. Program, the “Commercial Paper Programs”). Commercial paper may be issued in aggregate principal amounts of up to

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$1 billion under the U.S. Program and €625 million under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was $1.75 billion at December 31, 2021. The aggregate capacity of the U.S. Program was increased in the fourth quarter of 2021 from $900 million to $1 billion. The aggregate capacity of the Commercial Paper Program remains fully backed by the Company’s committed credit facilities. The U.S. Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, and Aon Global Holdings plc and the European Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, and Aon Corporation.

Approximately $400 million of the Termination Fee (as defined in Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations) was paid on July 27, 2021 using proceeds of commercial paper issued by Aon Corporation under the U.S. Program, where the aggregate principal was raised on July 26, 2021.

Commercial paper outstanding, which is included in Short-term debt and current portion of long-term debt in the Company’s Consolidated Statements of Financial Position, is as follows (in millions):

As of December 31	2021		2020
Commercial paper outstanding	$	665	$	—

The weighted average commercial paper outstanding and its related interest rates are as follows (in millions, except percentages):

	Years Ended December 31
	2021			2020
Weighted average commercial paper outstanding	$	273		$	343
Weighted average interest rate of commercial paper outstanding	0.01		%	1.47		%

8.    Lease Commitments

The classification of operating and finance lease asset and liability balances within the Consolidated Statements of Financial Position are as follows (in millions):

As of December 31		2021		2020
Assets
Operating lease assets	Operating lease right-of-use assets	$	786	$	911
Finance lease assets	Other non-current assets	63		89
Total lease assets		$	849	$	1,000
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	194	$	204
Finance	Other current liabilities	19		30
Non-current lease liabilities
Operating	Non-current operating lease liabilities	772		897
Finance	Other non-current liabilities	46		65
Total lease liabilities		$	1,031	$	1,196

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The components of lease costs are as follows (in millions):

	Years Ended December 31
	2021		2020
Operating lease cost	$	217	$	221
Finance lease costs
Amortization of leased assets	26		25
Interest on lease liabilities	1		3
Variable lease cost	49		48
Short-term lease cost (1)	11		10
Sublease income	(31)		(32)
Net lease cost	$	273	$	275

(1) Short-term lease cost does not include expenses related to leases with a lease term of one month or less.

Weighted average remaining lease term and discount rate related to operating and finance leases are as follows:

As of December 31	2021		2020
Weighted average remaining lease term (years)
Operating leases	6.9		7.4
Finance leases	3.6		4.2
Weighted average discount rate
Operating leases	2.8	%	2.9	%
Finance leases	1.0	%	1.0	%

Other cash and non-cash related activities are as follows (in millions):

	Years Ended December 31
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	244	$	236
Financing cash flows for finance leases	$	23	$	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	44	$	146
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	13
Operating lease ROU asset expense (1)	$	142	$	178
Changes in Non-current operating lease liabilities (1)	$	(125)	$	(47)

(1)The Company has recorded non-cash changes in Operating lease ROU assets and Non-current operating lease liabilities through Other assets and liabilities in Cash flows from operations within the Consolidated Statements of Cash Flows.

Maturity analysis of operating and finance leases as of December 31, 2021 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2022	$	207	$	26	$	233
2023	175		20		195
2024	144		18		162
2025	121		10		131
2026	110		—		110
Thereafter	299		—		299
Total undiscounted future minimum lease payments	1,056		74		1,130
Less: Imputed interest	(90)		(9)		(99)
Present value of lease liabilities	$	966	$	65	$	1,031

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9.    Income Taxes

Income before income tax and the provision for income tax consist of the following (in millions):

	Years Ended December 31
	2021		2020		2019
Income (loss) before income taxes:
Ireland	$	15	$	(86)	$	200
U.K.	549		634		228
U.S.	(818)		(28)		(220)
Other	2,185		1,946		1,662
Total	$	1,931	$	2,466	$	1,870
Income tax expense:
Current:
Ireland	$	2	$	2	$	1
U.K.	50		30		20
U.S. federal	197		126		22
U.S. state and local	72		22		41
Other	291		259		249
Total current tax expense	$	612	$	439	$	333
Deferred tax expense (benefit):
Ireland	$	(1)	$	(1)	$	(1)
U.K.	131		39		35
U.S. federal	(83)		(72)		(20)
U.S. state and local	(30)		(4)		(27)
Other	(6)		47		(23)
Total deferred tax expense (benefit)	$	11	$	9	$	(36)
Total income tax expense	$	623	$	448	$	297

Income before income taxes shown above is based on the location of the business unit to which such earnings are attributable for tax purposes. In addition, because the earnings shown above may, in some cases, be subject to taxation in more than one country, the income tax provision shown above as Ireland, U.K., U.S. or Other may not correspond to the geographic attribution of the earnings.

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The Company performs a reconciliation of the income tax provisions based on its domicile and statutory rate at each reporting period. Due to the Reorganization, the 2021 and 2020 reconciliations are based on the Irish statutory corporate tax rate of 25.0%, while the 2019 reconciliation is based on the U.K. statutory corporate tax rate of 19.0%. The reconciliation to the provisions reflected in the Consolidated Financial Statements is as follows:

	Years Ended December 31
	2021	2020	2019
Statutory tax rate	25.0%	25.0%	19.0%
U.S. state income taxes, net of U.S. federal benefit	1.5	1.0	0.5
Taxes on international operations (1) (4)	(15.4)	(9.8)	(6.0)
Nondeductible expenses	3.3	2.1	1.6
Adjustments to prior year tax requirements	(0.2)	—	0.1
Deferred tax adjustments, including statutory rate changes	3.2	0.7	—
Deferred tax adjustments, international earnings	1.8	0.7	—
Adjustments to valuation allowances	(0.2)	—	1.8
Change in uncertain tax positions	2.1	1.5	2.2
Excess tax benefits related to shared based compensation (2)	(2.4)	(2.2)	(2.8)
U.S. Tax Reform impact (3)	—	—	(0.3)
Capital Losses	—	(1.8)	—
Non-deductible transaction costs	1.1	1.3	—
Non-deductible termination fee	12.9	—	—
Other — net	(0.4)	(0.3)	(0.2)
Effective tax rate	32.3%	18.2%	15.9%

(1)The Company determines the adjustment for taxes on international operations based on the difference between the statutory tax rate applicable to earnings in each foreign jurisdiction and the enacted rate of 25.0%, 25.0% and 19.0% at December 31, 2021, 2020, and 2019, respectively. The benefit to the Company’s effective income tax rate from taxes on international operations relates to benefits from lower-taxed global operations, primarily due to the use of global funding structures and the tax holiday in Singapore.

(2)Excess tax benefits and deficiencies from share-based payment transactions are recognized as income tax expense or benefit in the Company’s Consolidated Statements of Income.

(3)The impact of the Tax Cuts and Jobs Act including adjustments to the Transition Tax.

(4)In July 2020, final U.S. tax regulations were issued regarding the GILTI high tax election, allowing taxpayers to exclude from GILTI the income of a Controlled Foreign Corporation that incurs a foreign tax rate more than 90% of the top U.S. corporate tax rate. A GILTI high tax election may be made on an annual basis, and taxpayers may choose to apply the election to taxable years beginning after December 31, 2017. The Company expects to make the GILTI high-tax election for 2021 and therefore recorded the impact of making the election.

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The Company has elected to account for GILTI in the period in which it is incurred, and therefore has not provided deferred tax impacts of GILTI in its Consolidated Financial Statements.

The components of the Company’s deferred tax assets and liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	581	$	653
Lease liabilities	207		248
Employee benefit plans	160		312
Other accrued expenses	132		103
Accrued interest	97		—
Federal and state benefit of interest from uncertain tax positions (1)	45		37
Deferred revenue	36		36
Investment basis differences	25		28
Lease and service guarantees	1		2
Other	25		17
Total	1,309		1,436
Valuation allowance on deferred tax assets	(230)		(205)
Total	$	1,079	$	1,231
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(243)	$	(291)
Lease right-of-use asset	(173)		(211)
Deferred costs	(159)		(141)
Unremitted earnings	(58)		(37)
Other accrued expenses	(27)		(22)
Unrealized foreign exchange gains	(22)		(26)
Other	(32)		(41)
Total	$	(714)	$	(769)
Net deferred tax asset	$	365	$	462

(1)The $37 million of Federal and state benefit of interest from uncertain tax positions as of December 31, 2020 was previously classified as Other.

Deferred income taxes (assets and liabilities have been netted by jurisdiction) have been classified in the Consolidated Statements of Financial Position as follows (in millions):

As of December 31	2021		2020
Deferred tax assets — non-current	766		724
Deferred tax liabilities — non-current	(401)		(262)
Net deferred tax asset	$	365	$	462

In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized and adjusts the valuation allowance accordingly. Considerations with respect to the realizability of deferred tax assets include the period of expiration of the deferred tax asset, historical earnings and projected future taxable income by jurisdiction as well as tax liabilities for the tax jurisdiction to which the tax asset relates. Significant management judgment is required in determining the assumptions and estimates related to the amount and timing of future taxable income. Valuation allowances have been established primarily with regard to the tax benefits of certain net operating loss, capital loss, and interest carryforwards. Valuation allowances increased by $25 million as of December 31, 2021, when compared to December 31, 2020. The change is primarily attributable to the increase in the UK tax rate offset by the release of valuation allowances related to certain net operating and capital loss carryforwards.

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The Company generally intends to limit distributions from foreign subsidiaries in excess of U.S. tax earnings and profits (except where distributions would be limited by available cash) and to limit repatriations from certain other jurisdictions that would otherwise generate a U.S. tax liability. As of December 31, 2021, the Company has accrued $58 million for local country income taxes, withholding taxes and state income taxes on those undistributed earnings that are not indefinitely reinvested. The Company has not provided for deferred taxes on outside basis differences in our investments in our foreign subsidiaries that are unrelated to these accumulated undistributed earnings, as these outside basis differences are indefinitely reinvested. A determination of the unrecognized deferred taxes related to these other components of our outside basis differences is not practicable.

The Company had the following carryforwards (in millions):

As of December 31	2021		2020
U.K.
Operating loss carryforwards	$	41	$	266
Capital loss carryforwards	$	573	$	577
Interest carryforwards	$	—	$	121
U.S.
Federal operating loss carryforwards	$	25	$	49
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	1,140	$	1,220
State operating loss carryforwards	$	398	$	378
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	551	$	573
Other Non-U.S.
Operating loss carryforwards	$	301	$	400
Capital loss carryforwards	$	35	$	42
Interest carryforwards	$	26	$	34
Other carryforwards	$	5	$	—

The U.K. operating losses, capital losses, and interest carryforward each have an indefinite carryforward period. The federal operating loss carryforwards generated through December 31, 2017 expire at various dates between 2034 and 2036 while federal operating loss carryforwards generated after this date have indefinite carryforward periods. State net operating losses as of December 31, 2021 have various carryforward periods and will begin to expire in 2022. Federal and state capital losses can be carried forward until 2023. Federal and state interest carryforwards have indefinite carryforward periods. Operating, capital losses, and other carryforwards in other non-U.S. jurisdictions have various carryforward periods and will begin to expire in 2022. The interest carryforwards in other non-U.S. jurisdictions have an indefinite carryforward period.

During 2012, the Company was granted a tax holiday for the period from October 1, 2012 through September 30, 2022, with respect to withholding taxes and certain income derived from services in Singapore. This tax holiday and reduced withholding tax rate may be extended when certain conditions are met or may be terminated early if certain conditions are not met. The benefit realized was approximately $104 million, $97 million, and $90 million during the years ended December 31, 2021, 2020, and 2019, respectively. The impact of this tax holiday on diluted earnings per share was $0.46, $0.42, and $0.37 during the years ended December 31, 2021, 2020, and 2019, respectively.

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Uncertain Tax Positions

The following is a reconciliation of the Company’s beginning and ending amount of uncertain tax positions (in millions):

	2021		2020
Balance at January 1	$	321	$	299
Additions based on tax positions related to the current year	33		25
Additions for tax positions of prior years	7		7
Reductions for tax positions of prior years	(4)		(3)
Settlements	—		—
Business combinations	—		—
Lapse of statute of limitations	(10)		(7)
Foreign currency translation	—		—
Balance at December 31	$	347	$	321

The Company’s liability for uncertain tax positions as of December 31, 2021, 2020, and 2019, includes $295 million, $270 million, and $248 million, respectively, related to amounts that would impact the effective tax rate if recognized. It is possible that the amount of unrecognized tax benefits may change in the next twelve months; however, the Company does not expect the change to have a significant impact on its consolidated statements of income or consolidated balance sheets. These changes may be the result of settlements of ongoing audits. At this time, an estimate of the range of the reasonably possible outcomes within the next twelve months cannot be made.

The Company recognizes interest and penalties related to uncertain tax positions in its provision for income taxes. The Company accrued potential interest and penalties of $22 million, $21 million, and $24 million in 2021, 2020, and 2019, respectively. The Company recorded a liability for interest and penalties of $142 million, $120 million, and $99 million as of December 31, 2021, 2020, and 2019, respectively.

The Company and its subsidiaries file income tax returns in their respective jurisdictions. The Company has substantially concluded all U.S. federal income tax matters for years through 2007. Material U.S. state and local income tax jurisdiction examinations have been concluded for years through 2012. The Company has concluded income tax examinations in its primary non-U.S. jurisdictions through 2008.

10.    Shareholders’ Equity

Distributable Profits

The Company is required under Irish law to have available “distributable profits” to make share repurchases or pay dividends to shareholders. Distributable profits are created through the earnings of the Irish parent company and, among other methods, through intercompany dividends or a reduction in share capital approved by the High Court of Ireland. Distributable profits are not linked to a U.S. GAAP reported amount (e.g., retained earnings). On July 26, 2021, we received approval from the High Court of Ireland to complete a reduction in share premium to create distributable profits of $34.0 billion to support the payment of possible future dividends or future share repurchases, if and to the extent declared by the directors in compliance with their duties under Irish law. As of December 31, 2021 and 2020, the Company had distributable profits in excess of $32.7 billion and $0.2 billion, respectively. We believe that we have the ability to create sufficient distributable profits for the foreseeable future.

Ordinary Shares

Aon has a share repurchase program authorized by the Company’s Board of Directors. The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in authorized repurchases in February 2022 for a total of $27.5 billion in repurchase authorizations.

Under the Repurchase Program, the Company’s class A ordinary shares may be repurchased through the open market or in privately negotiated transactions, from time to time, based on prevailing market conditions and will be funded from available capital.

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The following table summarizes the Company’s share repurchase activity (in millions, except per share data):

	Years Ended December 31
	2021		2020
Shares repurchased	12.4		8.5
Average price per share	$	286.82	$	206.28
Costs recorded to retained earnings
Total repurchase cost	$	3,543	$	1,761
Additional associated costs	—		2
Total costs recorded to retained earnings	$	3,543	$	1,763

At December 31, 2021, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $1.7 billion. Under the Repurchase Program, the Company has repurchased a total of 149.6 million shares for an aggregate cost of approximately $18.3 billion.

Weighted Average Ordinary Shares

Weighted average ordinary shares outstanding are as follows (in millions):

	Years Ended December 31
	2021	2020	2019
Basic weighted average ordinary shares outstanding	224.7	231.9	238.6
Dilutive effect of potentially issuable shares	1.4	1.2	2.0
Diluted weighted average ordinary shares outstanding	226.1	233.1	240.6

Potentially issuable shares are not included in the computation of Diluted net income per share attributable to Aon shareholders if their inclusion would be antidilutive. There were 0.3 million shares excluded from the calculation in 2021 and no shares excluded from the calculation in 2020 and 2019.

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Accumulated Other Comprehensive Loss

Changes in Accumulated other comprehensive loss by component, net of related tax, are as follows (in millions):

	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2018	(15)		(1,319)		(2,575)		(3,909)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	(10)		15		(287)		(282)
Tax benefit (expense)	1		(1)		58		58
Other comprehensive income (loss) before reclassifications, net	(9)		14		(229)		(224)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	14		—		109		123
Tax expense	(2)		—		(21)		(23)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		88		100
Net current period other comprehensive income (loss)	3		14		(141)		(124)
Balance at December 31, 2019	(12)		(1,305)		(2,716)		(4,033)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	1		258		(255)		4
Tax benefit	—		2		60		62
Other comprehensive income (loss) before reclassifications, net	1		260		(195)		66
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	15		—		125		140
Tax expense	(3)		—		(31)		(34)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		94		106
Net current period other comprehensive income (loss)	13		260		(101)		172
Balance at December 31, 2020	$	1	$	(1,045)	$	(2,817)	$	(3,861)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	—		(290)		227		(63)
Tax benefit (expense)	—		2		(58)		(56)
Other comprehensive income (loss) before reclassifications, net	—		(288)		169		(119)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	2		—		142		144
Tax expense	(1)		—		(34)		(35)
Amounts reclassified from accumulated other comprehensive income, net (3)	1		—		108		109
Net current period other comprehensive income (loss)	1		(288)		277		(10)
Balance at December 31, 2021	$	2	$	(1,333)	$	(2,540)	$	(3,871)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Consolidated Statements of Income. Refer to Note 13 “Derivatives and Hedging” for further information regarding the Company’s derivative and hedging activity.

(2)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Other income (expense) in the Consolidated Statements of Income.

(3)It is the Company’s policy to release income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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11.    Employee Benefits

Defined Contribution Savings Plans

Aon maintains defined contribution savings plans for the benefit of its employees. The expense recognized for these plans is included in Compensation and benefits in the Consolidated Statements of Income. The expense for the significant plans in the U.S., U.K., Netherlands, and Canada is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	103	$	87	$	98
U.K.	46		42		41
Netherlands and Canada	35		26		25
Total	$	184	$	155	$	164

Pension and Other Postretirement Benefits

The Company sponsors defined benefit pension and postretirement health and welfare plans that provide retirement, medical, and life insurance benefits. The postretirement health care plans are contributory, with retiree contributions adjusted annually, and the life insurance and pension plans are generally noncontributory. The significant U.S., U.K., Netherlands, and Canada pension plans are closed to new entrants.

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Pension Plans

The following tables provide a reconciliation of the changes in the projected benefit obligations and fair value of assets for the years ended December 31, 2021 and 2020, and a statement of the funded status as of December 31, 2021 and 2020, for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. These plans represent approximately 90% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2021		2020		2021		2020		2021		2020
Change in projected benefit obligation
At January 1	$	5,406	$	4,779	$	3,380	$	3,192	$	1,625	$	1,425
Service cost	1		—		—		—		—		—
Interest cost	65		88		57		85		12		19
Plan amendment	—		3		—		—		—		—
Settlements	(14)		(7)		—		—		—		—
Actuarial (gain) loss	(292)		520		(103)		274		24		112
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(58)		232		—		—		(83)		113
As of December 31	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Accumulated benefit obligation at end of year	$	4,919	$	5,406	$	3,164	$	3,380	$	1,504	$	1,592
Change in fair value of plan assets
At January 1	$	6,652	$	5,959	$	2,276	$	2,066	$	1,497	$	1,303
Actual return on plan assets	(136)		618		211		289		46		109
Employer contributions	9		8		61		92		17		20
Settlements	(14)		(7)		—		—		—		—
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(76)		283		—		—		(83)		109
As of December 31	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Market related value at end of year	$	6,246	$	6,652	$	2,174	$	2,076	$	1,430	$	1,497
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	1,327	$	1,246	$	(786)	$	(1,104)	$	(101)	$	(128)
Unrecognized prior-service cost	40		43		—		—		(6)		(7)
Unrecognized loss	1,215		1,286		1,551		1,812		489		521
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

Net actuarial gains decreased the benefit obligation in 2021 primarily due to the increase in the discount rates. During 2020, the net actuarial losses increased the benefit obligation primarily due to the decrease in discount rates.

In November 2020, the Company entered into an insurance contract that covers a portion of the assets within a select U.K. pension scheme. The transaction resulted in a decrease in Prepaid pension assets and Accumulated other comprehensive income of $94 million.

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Amounts recognized in the Consolidated Statements of Financial Position consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Prepaid benefit cost (1)	$	1,344	$	1,268	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(52)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(16)		(21)		(734)		(1,052)		(96)		(123)
Accumulated other comprehensive loss	1,255		1,329		1,551		1,812		483		514
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

(1)Included in Prepaid pension.

(2)Included in Other current liabilities.

(3)Included in Pension, other postretirement, and postemployment liabilities.

Amounts recognized in Accumulated other comprehensive loss (income) that have not yet been recognized as components of net periodic benefit cost at December 31, 2021 and 2020 consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Net loss	$	1,215	$	1,286	$	1,551	$	1,812	$	489	$	521
Prior service cost (income)	40		43		—		—		(6)		(7)
Total	$	1,255	$	1,329	$	1,551	$	1,812	$	483	$	514

In 2021, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $3.2 billion, an ABO of $3.2 billion, and plan assets with a fair value of $2.4 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $17 million, an ABO of $17 million and no plan assets. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.5 billion and plan assets with a fair value of $1.4 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $409 million and plan assets with a fair value of $326 million.

In 2020, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $3.3 billion, an ABO of $3.3 billion, and plan assets with a fair value of $2.2 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $54 million, an ABO of $54 million and plan assets with a fair value of $32 million. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.6 billion and plan assets with a fair value of $1.4 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $443 million and plan assets with a fair value of $342 million.

Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	U.K.						U.S.						Other
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Service cost	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	65		88		109		57		85		108		12		19		27
Expected return on plan assets, net of administration expenses	(137)		(159)		(191)		(130)		(134)		(136)		(32)		(34)		(40)
Amortization of prior-service cost	2		2		1		—		1		2		—		—		—
Amortization of net actuarial loss	32		30		29		78		68		53		15		12		12
Net periodic benefit (income) cost	(37)		(39)		(52)		5		20		27		(5)		(3)		(1)
Settlement expense	5		2		5		—		—		—		—		—		—
Total net periodic benefit cost (income)	$	(32)	$	(37)	$	(47)	$	5	$	20	$	27	$	(5)	$	(3)	$	(1)

The Company uses a full-yield curve approach in the estimation of the service and interest cost components of net periodic pension and postretirement benefit cost for its major pension and other postretirement benefit plans. This estimation was obtained by applying the specific spot rates along the yield curve used in the determination of the benefit obligation to the relevant projected cash flows.

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Transfer payments from certain U.K. pension plans exceeded the plan’s service and interest cost in 2021, 2020, and 2019. This triggered settlement accounting which required immediate recognition of a portion of the accumulated losses associated with the plan. Consequently, the Company recognized a non-cash settlement charge for approximately £3 million in 2021 ($5 million using December 31, 2021 exchange rates), approximately £2 million in 2020 ($2 million using December 31, 2020 exchange rates), and approximately £4 million in 2019 ($5 million using December 31, 2019 exchange rates).

The weighted-average assumptions used to determine benefit obligations are as follows:

	U.K.		U.S. (1)		Other
	2021	2020	2021	2020	2021	2020
Discount rate	1.96%	1.45%	2.23 - 2.80%	1.74 - 2.45%	1.00 - 2.97%	0.38 - 2.47%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.52%	2.12%	N/A	N/A	2.00%	2.00%

(1)U.S. pension plans are frozen and therefore not impacted by compensation increases or price inflation.

The weighted-average assumptions used to determine the net periodic benefit cost are as follows:

	U.K.			U.S.			Other
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Discount rate	1.20%	1.89%	2.95%	1.12 - 1.79%	2.36 - 2.76%	3.92 - 4.26%	0.28 - 2.00%	0.74 - 2.90%	1.89 - 3.88%
Expected return on plan assets, net of administration expenses	2.04%	2.74%	3.64%	2.65 - 6.56%	3.30- 7.04%	7.05%	1.70 - 2.65%	2.10 - 3.10%	2.50 - 4.10%
Rate of compensation increase	3.22 - 3.72%	3.24 - 3.74%	3.73 - 4.23%	N/A	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%	1.00 - 3.00%

Expected Return on Plan Assets

To determine the expected long-term rate of return on plan assets, the historical performance, investment community forecasts, and current market conditions are analyzed to develop expected returns for each asset class used by the plans. The expected returns for each asset class are weighted by the target allocations of the plans. The expected return of 6.56% on U.S. plan assets reflects a portfolio that is seeking asset growth through a higher equity allocation while maintaining prudent risk levels. The portfolio contains certain assets that have historically resulted in higher returns, as well as other financial instruments to minimize downside risk.

No plan assets are expected to be returned to the Company during 2022.

Fair value of plan assets

The Company determined the fair value of plan assets through numerous procedures based on the asset class and available information. Refer to Note 14 “Fair Value Measurements and Financial Instruments” for a description of the procedures performed to determine the fair value of the plan assets.

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The fair values of the Company’s U.S. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	93	$	93	$	—	$	—
Equity investments:
Equity securities	86		86		—		—
Equity derivatives	19		—		19		—
Pooled funds (2)	548		—		—		—
Fixed income investments:
Corporate bonds	249		—		249		—
Government and agency bonds	230		192		38		—
Pooled funds (2)	838		—		—		—
Other investments:
Real estate (2) (3)	156		—		—		—
Alternative investments (2) (4)	159		—		—		—
Total	$	2,378	$	371	$	306	$	—

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	79	$	79	$	—	$	—
Equity investments:
Equity securities	207		207		—		—
Equity derivatives	62		—		62		—
Pooled funds (2)	640		90		—		—
Fixed income investments:
Corporate bonds	167		—		167		—
Government and agency bonds	233		200		33		—
Pooled funds (2)	543		212		—		—
Other investments:
Real estate (2)(3)	163		—		—		—
Alternative investments (2) (4)	182		—		—		—
Total	$	2,276	$	788	$	262	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of property funds and trusts holding direct real estate investments.

(4)Consists of limited partnerships, private equity, and hedge funds.

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The fair values of the Company’s major U.K. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	872	$	872	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(1,640)		—		(1,640)		—
Government and agency bonds	2,969		2,969		—		—
Annuities	2,305		—		—		2,305
Pooled funds (2)	463		—		—		—
Other investments:
Real estate (2) (4)	130		—		—		—
Pooled funds (2) (5)	1,147		—		—		—
Total	$	6,246	$	3,841	$	(1,640)	$	2,305

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	182	$	182	$	—	$	—
Equity investments:
Pooled funds (2)	4		—		—		—
Fixed income investments:
Derivatives (3)	(1,424)		—		(1,424)		—
Corporate bonds	4		4		—		—
Government and agency bonds	2,872		2,872		—		—
Annuities	2,625		—		—		2,625
Pooled funds (2)	875		—		—		—
Other investments:
Real estate (2) (4)	117		—		—		—
Pooled funds (2) (5)	1,397		4		—		—
Total	$	6,652	$	3,062	$	(1,424)	$	2,625

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of equity securities and equity derivatives, including repurchase agreements.

(4)Consists of property funds and trusts holding direct real estate investments.

(5)Consists of multi-strategy limited partnerships, private equity, hedge funds, and collective investment schemes with a diversified portfolio of cash, equities, equity related securities, derivatives, and/or fixed income securities.

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The following table presents the changes in the Level 3 fair-value category in the Company’s U.K. pension plans for the years ended December 31, 2021 and December 31, 2020 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2020	$	1,849
Actual return on plan assets:
Relating to assets still held at December 31, 2020	13
Purchase, sales and settlements-net	682
Foreign exchange	81
Balance at December 31, 2020	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchases, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	$	2,305

The fair values of the Company’s other major pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	29	$	29	$	—	$	—
Equity investments:
Equity securities	72		72		—		—
Pooled funds (2)	316		—		—		—
Fixed income investments:
Government and agency bonds	350		350		—		—
Pooled funds (2)	597		—		—		—
Other investments:
Alternative investments (2) (3)	55		—		—		—
Real estate (2) (4)	11		—		—		—
Total	$	1,430	$	451	$	—	$	—

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			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	37	$	37	$	—	$	—
Equity investments:
Equity securities	75		75		—		—
Pooled funds (2)	290		—		—		—
Fixed income investments:
Government and agency bonds	395		395		—		—
Pooled funds (2)	627		—		—		—
Other investments:
Alternative investments (2) (3)	63		—		—		—
Real estate (2) (4)	10		—		—		—
Total	$	1,497	$	507	$	—	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of limited partnerships, private equity, and hedge funds.

(4)Consists of property funds and trusts holding direct real estate investments.

Investment Policy and Strategy

The U.S. investment policy, as established by the RPGIC, seeks reasonable asset growth at prudent risk levels within weighted average target allocations. At December 31, 2021, the weighted average targeted allocation for the U.S. plans was 31% for equity investments, 54% for fixed income investments, and 15% for other investments. Aon believes that plan assets are well-diversified and are of appropriate quality. The investment portfolio asset allocation is reviewed quarterly and re-balanced to be within policy target allocations. The investment policy is reviewed at least annually and revised, as deemed appropriate by the RPGIC. The investment policies for international plans are generally established by the local pension plan trustees and seek to maintain the plans’ ability to meet liabilities and to comply with local minimum funding requirements. Plan assets are invested in diversified portfolios that provide adequate levels of return at an acceptable level of risk. The investment policies are reviewed at least annually and revised, as deemed appropriate to ensure that the objectives are being met. At December 31, 2021, the weighted average targeted allocation for the U.K. and non-U.S. plans was 6% for equity investments, 88% for fixed income investments, and 6% for other investments.

Cash Flows

Contributions

Based on current assumptions, in 2022, the Company expects to contribute approximately $7 million, $52 million, and $15 million to its significant U.K., U.S., and other major pension plans, respectively.

Estimated Future Benefit Payments

Estimated future benefit payments for plans, not including voluntary one-time lump sum payments, are as follows at December 31, 2021 (in millions):

	U.K.		U.S.		Other
2022	$	164	$	193	$	47
2023	$	171	$	191	$	48
2024	$	177	$	193	$	49
2025	$	183	$	193	$	50
2026	$	188	$	183	$	52
2027 - 2031	$	1,017	$	882	$	275

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U.S. and Canadian Other Postretirement Benefits

The following table provides an overview of the accumulated PBO, fair value of plan assets, funded status and net amount recognized as of December 31, 2021 and 2020 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2021		2020
Accumulated projected benefit obligation	$	109	$	117
Fair value of plan assets	17		17
Funded status	(92)		(100)
Unrecognized prior-service credit	(1)		(1)
Unrecognized loss	2		13
Net amount recognized	$	(91)	$	(88)

Other information related to the Company’s other postretirement benefit plans are as follows:

	2021	2020	2019
Net periodic benefit cost recognized (millions)	$5	$4	$3
Weighted-average discount rate used to determine future benefit obligations	2.52 - 3.06%	2.10 - 2.58%	2.93 - 3.25%
Weighted-average discount rate used to determine net periodic benefit costs	1.45 - 2.68%	2.93 - 3.25%	3.91 - 4.26%

Based on current assumptions, the Company expects:

•The amount in Accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost during 2022 is $0.9 million net gain and $0.2 million of prior-service credit.

•To contribute $5 million to fund significant other postretirement benefit plans during 2022.

•Estimated future benefit payments will be approximately $5 million each year for 2022 through 2026, and $25 million in aggregate for 2027-2031.

12.    Share-Based Compensation Plans

The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):

	Years Ended December 31
	2021		2020		2019
Restricted share units	$	204	$	186	$	198
Performance share awards	189		116		110
Employee share purchase plans and other (1)	56		10		9
Total share-based compensation expense	449		312		317
Tax benefit	87		61		66
Share-based compensation expense, net of tax	$	362	$	251	$	251

(1) Includes expenses related to the Aon United Growth Ownership Plan.

Restricted Share Units

RSUs generally vest between three and five years. The fair value of RSUs is based upon the market value of the Company’s class A ordinary shares at the date of grant. With certain limited exceptions, any break in continuous employment will cause the forfeiture of all non-vested awards. Compensation expense associated with RSUs is recognized on a straight-line basis over the requisite service period. Dividend equivalents are paid on certain RSUs, based on the initial grant amount.

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The following table summarizes the status of the Company’s RSUs (shares in thousands, except fair value):

	Years Ended December 31
	2021			2020			2019
	Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)
Non-vested at beginning of year	3,309	$	163	3,634	$	143	4,208	$	120
Granted	1,257	$	253	1,329	$	185	1,306	$	175
Vested	(1,248)	$	151	(1,426)	$	133	(1,661)	$	113
Forfeited	(243)	$	184	(228)	$	157	(219)	$	131
Non-vested at end of year	3,075	$	203	3,309	$	163	3,634	$	143

(1)Represents per share weighted average fair value of award at date of grant.

The fair value of RSUs that vested during 2021, 2020 and 2019 was $189 million, $190 million, and $187 million, respectively.

Unamortized deferred compensation expense amounted to $447 million as of December 31, 2021, with a remaining weighted average amortization period of approximately 2.1 years.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of earnings per share related performance over a three-year period. The actual issuance of shares may range from 0-200% of the target number of PSAs granted, based on the terms of the plan and level of achievement of the related performance target. The grant date fair value of PSAs is based upon the market price of the Company’s class A ordinary shares at the date of grant. The performance conditions are not considered in the determination of the grant date fair value for these awards. Compensation expense is recognized over the performance period based on management’s estimate of the number of units expected to vest. Management evaluates its estimate of the actual number of shares expected to be issued at the end of the programs on a quarterly basis. The cumulative effect of the change in estimate is recognized in the period of change as an adjustment to Compensation and benefits in the Consolidated Statements of Income, if necessary. Dividend equivalents are not paid on PSAs.

The following table summarizes the Company’s target PSAs granted and shares that would be issued at current performance levels for PSAs granted during the years ended December 31, 2021, 2020, and 2019, respectively (shares in thousands and dollars in millions, except fair value):

	2021		2020		2019
Target PSAs granted during period	382		500		467
Weighted average fair value per share at date of grant	$	225	$	163	$	165
Number of shares that would be issued based on current performance levels	737		970		888
Unamortized expense, based on current performance levels	$	122	$	51	$	—

During 2021, the Company issued approximately 0.5 million shares in connection with performance achievements related to the 2018-2020 LPP. During 2020, the Company issued approximately 0.6 million shares in connection with performance achievements related to the 2017-2019 LPP cycle. During 2019, the Company issued approximately 0.7 million shares in connection with performance achievements related to the 2016-2018 LPP cycle.

13.    Derivatives and Hedging

The Company is exposed to market risks, including changes in foreign currency exchange rates and interest rates. To manage the risk related to these exposures, the Company enters into various derivative instruments that reduce these risks by creating offsetting exposures. The Company does not enter into derivative transactions for trading or speculative purposes.

Foreign Exchange Risk Management

The Company is exposed to foreign exchange risk when it earns revenues, pays expenses, enters into monetary intercompany transfers or other transactions denominated in a currency that differs from its functional currency. The Company uses foreign exchange derivatives, typically forward contracts, options and cross-currency swaps, to reduce its overall exposure to the effects of currency fluctuations on cash flows. These exposures are hedged, on average, for less than two years. These derivatives are accounted for as hedges, and changes in fair value are recorded each period in Other comprehensive income (loss) in the Consolidated Statements of Comprehensive Income.

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The Company also uses foreign exchange derivatives, typically forward contracts and options, to economically hedge the currency exposure of the Company’s global liquidity profile, including monetary assets or liabilities that are denominated in a non-functional currency of an entity, typically on a rolling 90-day basis, but may be for up to one year in the future. These derivatives are not accounted for as hedges, and changes in fair value are recorded each period in Other income in the Consolidated Statements of Income.

The notional and fair values of derivative instruments are as follows (in millions):

	Notional Amount				Net Amount of Derivative Assets Presented in the Statements of Financial Position (1)				Net Amount of Derivative Liabilities Presented in the Statements of Financial Position (2)
As of December 31	2021		2020		2021		2020		2021		2020
Foreign exchange contracts
Accounted for as hedges	$	629	$	633	$	27	$	33	$	—	$	—
Not accounted for as hedges (3)	412		367		2		1		—		1
Total	$	1,041	$	1,000	$	29	$	34	$	—	$	1

(1)Included within Other current assets ($21 million in 2021 and $11 million in 2020) or Other non-current assets ($8 million in 2021 and $23 million in 2020).

(2)Included within Other current liabilities ($1 million in 2020).

(3)These contracts typically are for 90-day durations and executed close to the last day of the most recent reporting month, thereby resulting in nominal fair values at the balance sheet date.

The amounts of derivative gains (losses) recognized in the Consolidated Financial Statements are as follows (in millions):

	2021		2020		2019
Gain (loss) recognized in Accumulated other comprehensive loss	$	—	$	1	$	(9)

The amounts of derivative gains (losses) reclassified from Accumulated other comprehensive loss to the Consolidated Statements of Income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Total revenue	$	(3)	$	(14)	$	(12)
Compensation and benefits	1		—		(1)
Interest expense	—		(1)		(1)
Total	$	(2)	$	(15)	$	(14)

The Company estimates that approximately $5 million of pretax gains currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

The Company recorded a loss of $24 million in 2021, a gain of $1 million in 2020, and a loss of $18 million in 2019 in Other income for foreign exchange derivatives not designated or qualifying as hedges.

Net Investments in Foreign Operations Risk Management

The Company uses non-derivative financial instruments to protect the value of its investments in a number of foreign subsidiaries. The Company has designated a portion of its euro-denominated commercial paper issuances as a non-derivative hedge of the foreign currency exposure of a net investment in its European operations. The change in fair value of the designated portion of the euro-denominated commercial paper due to changes in foreign currency exchange rates is recorded in Foreign currency translation adjustment, a component of Accumulated other comprehensive loss, to the extent it is effective as a hedge. The foreign currency translation adjustment of the hedged net investments is also recorded in Accumulated other comprehensive loss. Ineffective portions of net investment hedges, if any, are reclassified from Accumulated other comprehensive loss into earnings during the period of change.

The Company had no outstanding euro-denominated commercial paper at December 31, 2021 and 2020 designated as a hedge of the foreign currency exposure of its net investment in its European operations. The unrealized gain recognized in Accumulated other comprehensive loss related to the net investment non-derivative hedging instrument was $29 million, as of December 31, 2021 and 2020.

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The Company did not reclassify any deferred gains or losses related to net investment hedges from Accumulated other comprehensive loss to earnings for 2021, 2020, and 2019.

14.    Fair Value Measurements and Financial Instruments

Accounting standards establish a three-tier fair value hierarchy that prioritizes the inputs used in measuring fair values as follows:

•Level 1 — observable inputs such as quoted prices for identical assets in active markets;

•Level 2 — inputs other than quoted prices for identical assets in active markets, that are observable either directly or indirectly; and

•Level 3 — unobservable inputs in which there is little or no market data which requires the use of valuation techniques and the development of assumptions.

The following methods and assumptions are used to estimate the fair values of the Company’s financial instruments, including pension assets (refer to Note 11 “Employee Benefits”):

Money market funds consist of institutional prime, treasury, and government money market funds. The Company reviews treasury and government money market funds to obtain reasonable assurance that the fund net asset value is $1 per share and reviews the floating net asset value of institutional prime money market funds for reasonableness.

Cash and cash equivalents consist of cash and institutional short-term investment funds. The Company reviews the short-term investment funds to obtain reasonable assurance that the fund net asset value is $1 per share.

Equity investments consist of equity securities and equity derivatives valued using the closing stock price on a national securities exchange. Over the counter equity derivatives are valued using observable inputs such as underlying prices of the underlying security and volatility. On a sample basis the Company reviews the listing of Level 1 equity securities in the portfolio, agrees the closing stock prices to a national securities exchange, and independently verifies the observable inputs for Level 2 equity derivatives and securities.

Fixed income investments consist of certain categories of bonds and derivatives. Corporate, government, and agency bonds are valued by pricing vendors who estimate fair value using recently executed transactions and proprietary models based on observable inputs, such as interest rate spreads, yield curves, and credit risk. Asset-backed securities are valued by pricing vendors who estimate fair value using DCF models utilizing observable inputs based on trade and quote activity of securities with similar features. Fixed income derivatives are valued by pricing vendors using observable inputs such as interest rates and yield curves. The Company obtains an understanding of the models, inputs, and assumptions used in developing prices provided by its vendors through discussions with the fund managers. The Company independently verifies the observable inputs, as well as assesses assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on internal Company guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These adjustments do not occur frequently and historically are not material to the fair value estimates used in the Consolidated Financial Statements.

Pooled funds consist of various equity, fixed income, and real estate mutual fund type investment vehicles. Pooled investment funds fair value is estimated based on the proportionate share ownership in the underlying net assets of the investment, which is based on the fair value of the underlying securities. The underlying securities typically trade on a national securities exchange or may be valued by the fund managers using applicable models, inputs, and assumptions. The Company gains an understanding of the investment guidelines and valuation policies of the fund and discusses fund performance with pooled fund managers. The Company obtains audited fund manager financial statements, when available. If the pooled fund is designed to replicate a publicly traded index, the Company compares the performance of the fund to the index to assess the reasonableness of the fair value measurement.

Alternative investments consist of limited partnerships, private equity, and hedge funds. Alternative investment fair value is generally estimated based on the proportionate share ownership in the underlying net assets of the investment as determined by the general partner or investment manager. The valuations are based on various factors depending on investment strategy, proprietary models, and specific financial data or projections. The Company obtains audited fund manager financial statements, when available. The Company obtains a detailed understanding of the models, inputs, and assumptions used in developing prices provided by the investment managers, or appropriate party, through regular discussions. The Company also obtains the investment manger’s valuation policies and assesses the assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on the Company’s guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These

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adjustments do not occur frequently and historically are not material to the fair value estimates in the Consolidated Financial Statements.

Derivatives are carried at fair value, based upon industry standard valuation techniques that use, where possible, current market-based or independently sourced pricing inputs, such as interest rates, currency exchange rates, or implied volatility.

Annuity contracts consist of insurance group annuity contracts purchased to match the pension benefit payment stream owed to certain selected plan participant demographics within a few major U.K. defined benefit plans. Annuity contracts are valued using a DCF model utilizing assumptions such as discount rate, mortality, and inflation.

Real estate and REITs consist of publicly traded REITs and direct real estate investments. Level 1 REITs are valued using the closing stock price on a national securities exchange. Non-Level 1 values are based on the proportionate share of ownership in the underlying net asset value as determined by the investment manager. The Company independently reviews the listing of Level 1 REIT securities in the portfolio and agrees the closing stock prices to a national securities exchange. The Company gains an understanding of the investment guidelines and valuation policies of the non-Level 1 real estate funds and discusses performance with the fund managers. The Company obtains audited fund manager financial statements, when available. See the description of “Alternative investments” for further detail on valuation procedures surrounding non-Level 1 REITs.

Debt is carried at outstanding principal balance, less any unamortized issuance costs, discount or premium. Fair value is based on quoted market prices or estimates using DCF analyses based on current borrowing rates for similar types of borrowing arrangements.

The following tables present the categorization of the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2021 and December 31, 2020 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,918	$	2,918	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	40	$	—	$	40	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	11	$	—	$	11	$	—

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			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,781	$	2,781	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Equity investments	$	3	$	—	$	3	$	—
Derivatives (2)
Gross foreign exchange contracts	$	38	$	—	$	38	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	5	$	—	$	5	$	—

(1)Included within Fiduciary assets or Short-term investments in the Consolidated Statements of Financial Position, depending on their nature and initial maturity.

(2)Refer to Note 13 “Derivatives and Hedging” for additional information regarding the Company’s derivatives and hedging activity.

There were no transfers of assets or liabilities between fair value hierarchy levels during 2021 or 2020. The Company recognized no realized or unrealized gains or losses in the Consolidated Statements of Income related to assets and liabilities measured at fair value using unobservable inputs in 2021, 2020, or 2019.

The fair value of debt is classified as Level 2 of the fair value hierarchy. The following table provides the carrying value and fair value for the Company’s term debt (in millions):

	2021				2020
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	499	$	507	$	400	$	401
Long-term debt	$	8,228	$	9,204	$	7,281	$	8,752

15.    Claims, Lawsuits, and Other Contingencies

Legal

Aon and its subsidiaries are subject to numerous claims, tax assessments, lawsuits and proceedings that arise in the ordinary course of business, which frequently include E&O claims. The damages claimed in these matters are or may be substantial, including, in many instances, claims for punitive, treble, or extraordinary damages. While Aon maintains meaningful E&O insurance and other insurance programs to provide protection against certain losses that arise in such matters, Aon has exhausted or materially depleted its coverage under some of the policies that protect the Company and, consequently, is self-insured or materially self-insured for some claims. Accruals for these exposures, and related insurance receivables, when applicable, are included in the Consolidated Statements of Financial Position and have been recognized in Other general expense in the Consolidated Statements of Income to the extent that losses are deemed probable and are reasonably estimable. These amounts are adjusted from time to time as developments warrant. Matters that are not probable and reasonably estimable are not accrued for in the financial statements.

The Company has included in the current matters described below certain matters in which (1) loss (including interest and costs) is probable, (2) loss (including interest and costs) is reasonably possible (that is, more than remote but not probable), or (3) there exists the reasonable possibility of loss (including interest and costs) greater than the accrued amount. In addition, the Company may from time to time disclose matters for which the probability of loss could be remote but the claim amounts associated with such matters are potentially significant. The reasonably possible range of loss (including interest and costs) for the matters described below for which loss is estimable, in excess of amounts that are deemed probable and estimable and therefore already accrued, is estimated to be between $0 and $0.8 billion, exclusive of any insurance coverage. These estimates are based on available information as of the date of this filing. As available information changes, the matters for which Aon is able to estimate, and the estimates themselves, may change. In addition, many estimates involve significant judgment and uncertainty. For example, at the time of making an estimate, Aon may only have limited information about the facts underlying the claim and predictions and assumptions about future court rulings and outcomes may prove to be inaccurate. Although

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management at present believes that the ultimate outcome of all matters described below, individually or in the aggregate, will not have a material adverse effect on the consolidated financial position of Aon, legal proceedings are subject to inherent uncertainties and unfavorable rulings or other events. Unfavorable resolutions could include substantial monetary or punitive damages imposed on Aon or its subsidiaries. If unfavorable outcomes of these matters were to occur, future results of operations or cash flows for any particular quarterly or annual period could be materially adversely affected.

Current Matters

On October 3, 2017, CCC invoked arbitration to pursue a claim that it asserts against Aon New Zealand. Aon provided insurance broking services to CCC in relation to CCC’s 2010-2011 material damage and business interruption program. In December 2015, CCC settled its property and business interruption claim for its losses arising from the 2010-2011 Canterbury earthquakes against the underwriter of its material damage and business interruption program and the reinsurers of that underwriter. CCC contends that acts and omissions by Aon caused CCC to recover less in that settlement than it otherwise would have. CCC claims damages of approximately NZD 320 million ($218 million at December 31, 2021 exchange rates) plus interest and costs. Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon Hewitt Investment Consulting, Inc, now known as Aon Investments USA, Inc. (“Aon Investments”), Lowe’s Companies, Inc. and the Administrative Committee of Lowe’s Companies, Inc. (collectively “Lowe’s”) were sued on April 27, 2018 in the U.S. District Court for the Western District of North Carolina (the “Court”) in a class action lawsuit brought on behalf of participants in the Lowe’s 401(k) Plan (the “Plan”). Aon Investments provided investment consulting services to Lowe’s under the ERISA. The plaintiffs contend that in 2015 Lowe’s imprudently placed the Hewitt Growth Fund in the Plan’s lineup of investments, the Hewitt Growth Fund underperformed its benchmarks, and that Aon had a conflict of interest in recommending the proprietary fund for the Plan. The plaintiffs allege the Plan suffered over $200 million in investment losses when compared to the eight funds it replaced. The plaintiffs allege that Aon Investments breached its duties of loyalty and prudence pursuant to the ERISA statute. The matter was tried to the Court the last week of June 2021, and the Court entered judgment in favor of Aon on all claims on October 12, 2021. Plaintiffs have filed an appeal with the United States Court of Appeals for the Fourth Circuit. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims.

A retail insurance brokerage subsidiary of Aon was sued on September 6, 2018 in the United States District Court for the Southern District of New York by a client, Pilkington North America, Inc., that sustained damage from a tornado to its Ottawa, Illinois property. The lawsuit seeks between $45 million and $85 million in property and business interruption damages from either its insurer or Aon. The insurer contends that insurance proceeds were limited to $15 million in coverage by a windstorm sub-limit purportedly contained in the policy procured by Aon for Pilkington. The insurer therefore has tendered $15 million to Pilkington and denied coverage for the remainder of the loss. Pilkington sued the insurer and Aon seeking full coverage for the loss from the insurer or, in the alternative, seeking the same damages against Aon on various theories of professional liability if the court finds that the $15 million sub-limit applies to the claim. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon faces legal action arising out of a fatal plane crash in November 2016. Aon U.K. Limited placed an aviation civil liability reinsurance policy for the Bolivian insurer of the airline. After the crash, the insurer determined that there was no coverage under the airline’s insurance policy due to the airline’s breach of various policy conditions. In November 2018, the owner of the aircraft filed a claim in Bolivia against Aon, the airline, the insurer and the insurance broker. The claim is for $16 million plus any liability the owner has to third parties. In November 2019, a federal prosecutor in Brazil filed a public civil action naming three Aon entities as defendants, along with the airline, the insurer, and the lead reinsurer. That claim seeks pecuniary damages for families affected by the crash in the sum of $300 million; or, in the alternative, $50 million; or, in the alternative, $25 million; plus “moral damages” of an equivalent sum. Separately, in March 2020, the Brazilian Federal Senate invited Aon to give evidence to a Parliamentary Commission of Inquiry in an investigation into the accident. Aon is cooperating with that inquiry. In August 2020, 43 individuals (surviving passengers and estates of the deceased) filed a motion in the Circuit Court of the 11th Judicial Circuit in and for Miami-Dade County, Florida, seeking permission to commence proceedings against Aon (and the insurer and reinsurers) for claims totaling $844 million. Finally, in April 2021, representatives of 16 passengers issued a claim against Aon in the High Court in England seeking damages under the Fatal Accidents Act 1976 in the sum of £29 million ($39 million at December 31, 2021 exchange rates). Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon Investments and AGI were sued on September 16, 2020, in the U.S. District Court for the Southern District of New York by the Blue Cross and Blue Shield Association NEBC. Aon Investments and its predecessors provided investment advisory services to NEBC since 2009. The NEBC contends that it suffered investment losses exceeding $2 billion in several Structured Alpha funds managed by AGI and recommended by Aon. The NEBC is pursuing claims against Aon Investments for breach of fiduciary duty and breach of cofiduciary duty. The NEBC alleges that Aon Investments and AGI are jointly and severally liable for damages, which include the restoration of investment losses, disgorgement of fees and profits, and attorneys’ fees. Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

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In April 2017, the FCA announced an investigation relating to suspected competition law breaches in the aviation and aerospace broking industry, which, for Aon in 2016, represented less than $100 million in global revenue. The European Commission assumed jurisdiction over the investigation in place of the FCA, and the European Commission has now closed its investigation. Other antitrust agencies outside the E.U. are conducting formal or informal investigations regarding these matters. Aon intends to work diligently with all antitrust agencies concerned to ensure they can carry out their work as efficiently as possible. At this time, in light of the uncertainties and many variables involved, Aon cannot estimate the ultimate impact on our company from these investigations or any related private litigation, nor any damages, penalties, or fines related to them.

Guarantees and Indemnifications

The Company provides a variety of guarantees and indemnifications to its customers and others. The maximum potential amount of future payments represents the notional amounts that could become payable under the guarantees and indemnifications if there were a total default by the guaranteed parties, without consideration of possible recoveries under recourse provisions or other methods. These amounts may bear no relationship to the expected future payments, if any, for these guarantees and indemnifications. Any anticipated amounts payable are included in the Financial Statements and are recorded at fair value.

The Company expects that, as prudent business interests dictate, additional guarantees and indemnifications may be issued from time to time.

Guarantee of Registered Securities

In connection with the Reorganization, on April 1, 2020 Aon plc and Aon Global Holdings plc, a company incorporated under the laws of England and Wales, entered into various agreements pursuant to which they agreed to guarantee the obligations of Aon Corporation arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Global Limited and the obligations of Aon Global Limited arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Corporation. Those agreements include: (1) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, and Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”) (amending and restating the Amended and Restated Indenture, dated April 2, 2012, among Aon Corporation, Aon Global Limited and the Trustee); (2) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 12, 2012, among Aon Corporation, Aon Global Limited plc and the Trustee); (3) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated May 20, 2015, among Aon Corporation, Aon Global Limited and the Trustee); (4) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated November 13, 2015, among Aon Corporation, Aon Global Limited and the Trustee); and (5) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 3, 2018, among Aon Corporation, Aon Global Limited and the Trustee).

Sale of the Divested Business

In connection with the sale of the Divested Business, the Company guaranteed future operating lease commitments related to certain facilities assumed by the buyer. The Company is obligated to perform under the guarantees if the Divested Business defaults on such leases at any time during the remainder of the lease agreements, which expire on various dates through 2025. As of December 31, 2021, the undiscounted maximum potential future payments under the lease guarantee were $40 million, with an estimated fair value of $5 million. No cash payments were made in connection with the lease commitments during the year ended December 31, 2021.

Additionally, the Company is subject to performance guarantee requirements under certain client arrangements that were assumed by the buyer. Should the Divested Business fail to perform as required by the terms of the arrangements, the Company would be required to fulfill the remaining contract terms, which expire on various dates through 2023. As of December 31, 2021, the undiscounted maximum potential future payments under the performance guarantees were $52 million, with an estimated fair value of less than $1 million. No cash payments were made in connection to the performance guarantees during the year ended December 31, 2021.

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Letters of Credit

Aon has entered into a number of arrangements whereby the Company’s performance on certain obligations is guaranteed by a third party through the issuance of LOCs. The Company had total LOCs outstanding of approximately $75 million at December 31, 2021, and $79 million at December 31, 2020. These LOCs cover the beneficiaries related to certain of Aon’s U.S. and Canadian non-qualified pension plan schemes and secure deductible retentions for Aon’s own workers compensation program. The Company has also obtained LOCs to cover contingent payments for taxes and other business obligations to third parties, and other guarantees for miscellaneous purposes at its international subsidiaries.

Premium Payments

The Company has certain contractual contingent guarantees for premium payments owed by clients to certain insurance companies. The maximum exposure with respect to such contractual contingent guarantees was approximately $153 million at December 31, 2021 compared to $113 million at December 31, 2020.

16.    Segment Information

The Company operates as one segment that includes all of Aon’s operations, which as a global professional services firm provides a broad range of risk, health, and wealth solutions through four solution lines which make up its principal products and services. The CODM assesses the performance of the Company and allocates resources based on one segment: Aon United.

The Company’s reportable operating segment has been determined using a management approach, which is consistent with the basis and manner in which the CODM uses financial information for the purposes of allocating resources and evaluating performance. The CODM assesses performance and allocates resources based on total Aon results against its key four metrics, including organic revenue growth, expense discipline, and collaborative behaviors that maximize value for Aon and its shareholders, regardless of which solution line it benefits.

As Aon operates as one segment, segment profit or loss is consistent with consolidated reporting as disclosed in the Consolidated Statements of Income. Refer to Note 3 “Revenue from Contracts with Customers” for further information on revenue by principal service line.

Consolidated long-lived assets, net by geographic area are as follows (in millions):

As of December 31	Total		United States	Americas other than U.S.	United Kingdom	Ireland	Other Europe, Middle East, & Africa	Asia Pacific
2021	$	1,378	563	121	180	7	293	214
2020	$	1,599	681	127	213	11	357	210

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Item 9.    Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

None.

Item 9A.    Controls and Procedures

Evaluation of Disclosure Controls and Procedures

We have conducted an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures, as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) as of the end of the period covered by this annual report of December 31, 2021. Based on this evaluation, our chief executive officer and chief financial officer concluded as of December 31, 2021 that our disclosure controls and procedures were effective such that the information relating to Aon, including our consolidated subsidiaries, required to be disclosed in our SEC reports is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms, and is accumulated and communicated to Aon’s management, including our chief executive officer and chief financial officer, as appropriate to allow timely decisions regarding required disclosure.

Management’s Report on Internal Control Over Financial Reporting

Management of Aon plc is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act. The Company’s internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Under the supervision and with the participation of our senior management, including our Chief Executive Officer and Chief Financial Officer, we assessed the effectiveness of our internal control over financial reporting as of December 31, 2021. In making this assessment, we used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in the Internal Control — Integrated Framework (2013 Framework). Based on this assessment, management has concluded our internal control over financial reporting is effective as of December 31, 2021.

The effectiveness of our internal control over financial reporting as of December 31, 2021 has been audited by Ernst & Young, LLP, the Company’s independent registered public accounting firm, as stated in their report titled “Report of Independent Registered Public Accounting Firm on Internal Control over Financial Reporting.”

Changes in Internal Control Over Financial Reporting

No changes in Aon’s internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) occurred during 2021 that have materially affected, or that are reasonably likely to materially affect, Aon’s internal control over financial reporting.

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Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders of Aon plc

Opinion on Internal Control over Financial Reporting

We have audited Aon plc’s internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 Framework), (the COSO criteria). In our opinion, Aon plc (the Company) maintained, in all material respects, effective internal control over financial reporting as of December 31, 2021, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated statements of financial position of the Company as of December 31, 2021 and 2020, and the related consolidated statements of income, comprehensive income, shareholders' equity and cash flows for each of the three years in the period ended December 31, 2021, and the related notes and our report dated February 18, 2022 expressed an unqualified opinion thereon.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control Over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects.

Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

Definition and Limitations of Internal Control Over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Chicago, Illinois

February 18, 2022

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Item 9B.    Other Information

Not applicable.

Item 9C.    Disclosure Regarding Foreign Jurisdictions that Prevents Inspections

Not applicable.

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PART III

Item 10.    Directors, Executive Officers and Corporate Governance

Information relating to Aon’s directors is set forth under the heading “Proposal 1 — Resolutions Regarding the Election of Directors” in the Proxy Statement for the 2022 Annual General Meeting of Shareholders (the “Proxy Statement”) and is incorporated herein by reference. Information relating to Aon’s executive officers is set forth in Part I of this report and is incorporated herein by reference. The remaining information required by this item is set forth under the headings “Corporate Governance” and “Board of Directors and Committees” in the Proxy Statement, and all such information is incorporated herein by reference.

We have adopted a code of ethics that applies to the Company’s directors, officers, and employees, including the Chief Executive Officer, Chief Financial Officer, Controller, and Chief Accounting Officer and other persons performing similar functions. The text of our code of ethics, which we call our Code of Business Conduct, is available on our website as disclosed in Part 1 of this report. We will provide a copy of the code of ethics without charge upon request to the Company Secretary, Metropolitan Building, James Joyce Street, Dublin 1, Ireland. We will disclose on our website any amendment to or waiver from our code of ethics on behalf of any of our executive officers or directors.

Item 11.    Executive Compensation

Information relating to director and executive officer compensation is set forth under the headings “Compensation Committee Report,” “Compensation Discussion and Analysis,” and “Executive Compensation” in the Proxy Statement, and all such information is incorporated herein by reference.

The material incorporated herein by reference to the information set forth under the heading “Compensation Committee Report” in the Proxy Statement shall be deemed furnished, and not filed, in this Form 10-K and shall not be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act as a result of this furnishing, except to the extent that it is specifically incorporated by reference by Aon.

Information relating to compensation committee interlocks and insider participation is set forth under the heading “Compensation Discussion and Analysis - Compensation Committee Interlocks and Insider Participation” in the Proxy Statement and is incorporated herein by reference.

Item 12.    Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Information relating to equity compensation plans and the security ownership of certain beneficial owners and management of Aon plc’s ordinary shares is set forth under the headings “Equity Compensation Plan Information,” “Principal Holders of Voting Securities,” and “Security Ownership of Directors and Executive Officers” in the Proxy Statement, and all such information is incorporated herein by reference.

Item 13.    Certain Relationships and Related Transactions, and Director Independence

Information required by this Item is included under the headings “Corporate Governance — Director Independence” and “Certain Relationships and Related Transactions” in the Proxy Statement and is incorporated herein by reference.

Item 14.    Principal Accountant Fees and Services

Information required by this Item is included under the heading “Auditor Fees” in the Proxy Statement and is incorporated herein by reference.

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PART IV

Item 15.    Exhibits and Financial Statement Schedules

(a)	(1) and (2). The following documents have been included in Part II, Item 8.
	Report of Ernst & Young LLP, Independent Registered Public Accounting Firm (PCAOB ID: 42), on Financial Statements
	Consolidated Statements of Financial Position — As of December 31, 2021 and 2020
	Consolidated Statements of Income — Years Ended December 31, 2021, 2020, and 2019
	Consolidated Statements of Comprehensive Income — Years Ended December 31, 2021, 2020 and 2019
	Consolidated Statements of Shareholders’ Equity — Years Ended December 31, 2021, 2020 and 2019
	Consolidated Statements of Cash Flows — Years Ended December 31, 2021, 2020 and 2019
	Notes to Consolidated Financial Statements

The following document has been included in Part II, Item 9.

Report of Ernst & Young LLP, Independent Registered Public Accounting Firm, on Internal Control over Financial Reporting

All schedules for the Registrant and consolidated subsidiaries have been omitted because the required information is not present in amounts sufficient to require submission of the schedules or because the information required is included in the respective financial statements or notes thereto.

(a)(3). List of Exhibits (numbered in accordance with Item 601 of Regulation S-K)
	Plan of Acquisition, Reorganization, Arrangement, Liquidation or Succession.
		2.1*	Business Combination Agreement, dated March 9, 2020, between Aon plc and Willis Towers Watson Public Limited Company (“WTW”) - incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8-K filed March 10, 2020.
		2.2*	Appendix 3 to the Rule 2.5 Announcement, dated March 9, 2020 - incorporated by reference to Exhibit 2.2 to Aon’s Current Report on Form 8-K filed March 10, 2020.
		2.3*	Expenses Reimbursement Agreement, dated March 9, 2020, between Aon plc and WTW - incorporated by reference to Exhibit 2.3 to Aon’s Current Report on Form 8-K filed March 10, 2020.
		2.4*	Assignment Agreement, dated April 2, 2020, between Aon plc and Aon plc (UK) - incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8-K filed April 2, 2020.
		2.5*	Amendment No. 1 to the Business Combination Agreement, dated October 30, 2020, between Aon plc and WTW - incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8-K filed October 30, 2020.
	Articles of Association.
		3.1*	Memorandum and Articles of Association of Aon plc - incorporated by reference to Exhibit 3.1 to Aon’s Current Report on Form 8-K filed June 4, 2021.
	Instruments Defining the Rights of Security Holders, Including Indentures.
		4.1*	Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the Indenture, dated January 13, 1997) - incorporated by reference to Exhibit 4.1 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
		4.2*	Capital Securities Guarantee Agreement dated as of January 13, 1997 between Aon and The Bank of New York, as Guarantee Trustee — incorporated by reference to Exhibit 4.8 to Aon’s Registration Statement on Form S-4 (File No. 333-21237) filed on February 6, 1997.
		4.3*	Capital Securities Exchange and Registration Rights Agreement dated as of January 13, 1997 among Aon, Aon Capital A, Morgan Stanley & Co. Incorporated and Goldman, Sachs & Co. — incorporated by reference to Exhibit 4.10 to Aon’s Registration Statement on Form S-4 (File No. 333-21237) filed on February 6, 1997.
		4.4*	Debenture Exchange and Registration Rights Agreement dated as of January 13, 1997 among Aon, Aon Capital A, Morgan Stanley & Co. Incorporated and Goldman, Sachs & Co. — incorporated by reference to Exhibit 4.11 to Aon’s Registration Statement on Form S-4 (File No. 333-21237) filed on February 6, 1997.

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4.5*	Guarantee Exchange and Registration Rights Agreement dated as of January 13, 1997 among Aon, Aon Capital A, Morgan Stanley & Co. Incorporated and Goldman, Sachs & Co. — incorporated by reference to Exhibit 4.12 to Aon’s Registration Statement on Form S-4 (File No. 333-21237) filed on February 6, 1997.
4.6*	Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the Indenture, dated September 10, 2010) - incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.7*	Form of 6.25% Senior Note due 2040 — incorporated by reference to Exhibit 4.4 to Aon’s Current Report on Form 8-K filed on September 10, 2010.
4.8*	Indenture dated as of March 8, 2011, among Aon Finance N.S. 1, ULC, Aon Corporation and Computershare Trust Company of Canada. — incorporated by reference to Exhibit 4.1 to Aon’s Current Report on Form 8-K filed on March 8, 2011.
4.9*	First Supplemental Indenture, dated April 2, 2012, among Aon Finance N.S. 1, ULC, Aon Corporation, Aon plc and Computershare Trust Company of Canada (supplementing the Indenture, dated March 8, 2011) - incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.
4.10*	Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Indenture, dated December 12, 2012) - incorporated by reference to Exhibit 4.3 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.11*	Form of 4.250% Senior Note Due 2042 - incorporated by reference to Exhibit 4.6 to Aon’s Registration Statement on Form S-4 (File No. 333-187637) filed on March 29, 2013.
4.12*	Second Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Amended and Restated Indenture, dated May 20, 2015, amending and restating the Indenture, dated May 24, 2013) - incorporated by reference to Exhibit 4.4 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.13*	Form of 4.45% Senior Note due 2043 — incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed on May 24, 2013.
4.14*	Form of 4.00% Senior Note due 2023 — incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed on November 26, 2013.
4.15*	Form of 3.500% Senior Note due 2024 - incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed on May 27, 2014.
4.16*	Form of 4.600% Senior Note due 2044 - incorporated by reference to Exhibit 4.3 to Aon’s Current Report on Form 8-K filed on May 27, 2014.
4.17*	Form of 4.750% Senior Note due 2045 - incorporated by reference to Exhibit 4.1 to Aon’s Current Report on Form 8-K filed on May 20, 2015.
4.18*	Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Indenture, dated November 13, 2015) - incorporated by reference to Exhibit 4.5 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.19*	Form of 3.875% Senior Note due 2025 - incorporated by reference to Exhibit 1.1 to Aon’s Current Report on Form 8-K filed on February 29, 2016.
4.20*	Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A. (amending and restating the Indenture, dated December 3, 2018) - incorporated by reference to Exhibit 4.6 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.21*	Form of 4.500% Senior Note due 2028 - incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed December 3, 2018.
4.22*	Form of 3.750% Senior Note due 2029, incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed May 2, 2019.
4.23*	Form of 2.200% Senior Note due 2022, incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed November 15, 2019.

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4.24*	Form of 2.800% Senior Note due 2030 - incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed May 15, 2020.
4.25*	Description of Securities of Aon plc that are registered under Section 12 of the Securities Exchange Act of 1934, as amended - incorporated by reference to Exhibit 4.7 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
4.26*	First Indenture Supplement, dated August 23, 2021, among Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Aon plc and The Bank of New York Mellon Trust Company, N.A., as trustee – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed August 23, 2021.
4.27*	Form of 2.050% Senior Note due 2031 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed August 23, 2021.
4.28*	Form of 2.900% Senior Note due 2051 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed August 23, 2021.
4.29*	Second Indenture Supplement, dated December 2, 2021, among Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Aon plc and The Bank of New York Mellon Trust Company, N.A., as trustee – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed December 2, 2021.
4.30*	Form of 2.600% Senior Note due 2031 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed December 2, 2021.

Material Contracts.
	10.1*	$1,000,000,000 Credit Agreement, dated September 28, 2021, among Aon plc, Aon Corporation, Aon UK Limited, Aon Global Holdings plc and Aon Global Limited with Citibank, N.A., as administrative agent, the lenders party thereto, HSBC Bank USA, National Association and Morgan Stanley Senior Funding, Inc., as syndication agents, and Citibank, N.A., HSBC Securities (USA) and Morgan Stanley Senior Funding, Inc., as joint lead arrangers and joint bookrunners - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on September 30, 2021.
	10.2*	$400,000,000 Five-Year Credit Agreement, dated October 19, 2017 (the “2017 Credit Agreement”), among Aon plc, Aon Corporation, Citibank, N.A., as administrative agent, the lenders party thereto, HSBC Bank USA, National Association, as syndication agent, and Citigroup Global Markets, Inc. and HSBC Securities (USA) Inc., as joint lead arrangers and joint bookrunners - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed October 20, 2017.
	10.3*	Form of Notice of Extension of the 2017 Credit Agreement - incorporated by reference to Exhibit 10.7 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2019.
	10.4*	Lender Assumption Agreement, dated February 27, 2020, among Aon plc, Citibank, N.A. and the parties thereto, with respect to the 2017 Credit Agreement - incorporated by reference to Exhibit 10.12 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
	10.5*	Waiver and Amendment No. 1 to the 2017 Credit Agreement, dated April 1, 2020, among Aon plc, Aon Corporation, Citibank, N.A. and the lenders party thereto - incorporated by reference to Exhibit 10.11 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
	10.6*	Amendment No. 2 to the 2017 Credit Agreement, dated September 28, 2021, among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Citibank, N.A., as administrative agent, and the lenders party thereto - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed on September 30, 2021.
	10.7*	Purchase Agreement, dated February 9, 2017, between Aon plc and Tempo Acquisition, LLC - incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8-K filed February 10, 2017.
	10.8*	Amendment No. 1 to Purchase Agreement, dated April 17, 2017, between Aon plc and Tempo Acquisition, LLC - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on 10-Q for the quarter ended March 31, 2017.
	10.9*#	Deed of Assumption of Aon plc, dated April 1, 2020 - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
	10.10*#	Deed of Assumption of Aon Global Limited, dated April 2, 2012 - incorporated by reference to Exhibit 10.7 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.

106

10.11*#	Aon Corporation Outside Director Corporate Bequest Plan (as amended and restated, effective January 1, 2010) - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2010.
10.12*#	Amended and Restated Aon Stock Incentive Plan - incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed May 24, 2006.
10.13*#	First Amendment to the Amended and Restated Aon Stock Incentive Plan - incorporated by reference to Exhibit 10(au) to Aon’s Annual Report on Form 10-K for the year ended December 31, 2006.
10.14*#	Second Amendment to the Amended and Restated Aon Stock Incentive Plan, dated April 2, 2012 - incorporated by reference to Exhibit 10.10 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.
10.15*#	Aon Stock Award Plan (as amended and restated through February 2000) - incorporated by reference to Exhibit 10(a) to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2000.
10.16*#	First Amendment to the Aon Stock Award Plan - incorporated by reference to Exhibit 10(as) to Aon’s Annual Report on Form 10-K for the year ended December 31, 2006.
10.17*#	Aon plc 2011 Incentive Plan (as amended and restated, effective March 29, 2019) - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2019.
10.18*#	First Amendment to the Aon plc 2011 Incentive Plan, effective September 13, 2021 - incorporated by reference to Exhibit 10.9 to Aon’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2021.
10.19*#	Aon plc Executive Committee Incentive Compensation Plan - incorporated by reference to Exhibit 10.3 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2016.
10.20#	Aon plc Leadership Performance Program (as amended and restated, effective January 1, 2021)
10.21*#	Aon plc Senior Executive Combined Severance and Change in Control Plan (as amended and restated, effective June 21, 2019) - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter end June 30, 2019.
10.22*#	First Amendment to the Aon plc Amended and Restated Senior Executive Combined Severance and Change in Control Plan, effective September 30, 2021 - incorporated by reference to Exhibit 10.10 to Aon’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2021.
10.23*#	Aon plc Senior Executive Incentive Compensation Plan (as amended and restated, effective January 1, 2021) - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2021.
10.24*#	Form of Deed of Indemnity of Aon plc - incorporated by reference to Exhibit 10.4 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
10.25*#	Form of Deed of Indemnity for Directors of Aon Global Limited - incorporated by reference to Exhibit 10.4 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.
10.26*#	Form of Deed of Indemnity for Gregory C. Case - incorporated by reference to Exhibit 10.5 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.
10.27*#	Form of Deed of Indemnity for Executive Officers of Aon plc - incorporated by reference to Exhibit 10.6 to Aon’s Current Report on Form 8-K12B filed April 2, 2012.
10.28*#	Form of Service as a Non-Executive Director Agreement - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2016.
10.29*#	Amended and Restated Employment Agreement, dated January 16, 2015, among Aon plc, Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed January 23, 2015.
10.30*#	Amendment to Employment Agreement, dated April 20, 2018, among Aon plc, Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed April 25, 2018.
10.31*#	Amendment to Employment Agreement, dated May 10, 2018, by and among Aon plc, Aon Corporation, and Gregory C. Case - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on May 15, 2018.

107

10.32*#	Amendment to Employment Agreement, dated July 26, 2021, among Aon plc, Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.3 to Aon’s Current Report on Form 8-K filed on July 26, 2021.
10.33*#	Amended and Restated Change in Control Agreement, dated November 13, 2009, between Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed on November 17, 2009.
10.34*#	Amendment to the Amended and Restated Change in Control Agreement, dated April 27, 2016, between Aon plc and Gregory C. Case - incorporated by reference to Exhibit 10.11 on Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2016.
10.35*#	International Assignment Letter, effective July 1, 2016, between Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2016.
10.36*#	Amendment to International Assignment Letter, dated June 25, 2018, with Gregory C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed on June 27, 2018.
10.37*#	Amendment to International Assignment Letter, dated June 25, 2019, with Gregory C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed on June 25, 2019.
10.38*#	Amendment to International Assignment Letter, dated June 19, 2020, between Aon Corporation and Greg C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed June 25, 2020.
10.39*#	Amendment to International Assignment Letter, dated July 8, 2021, between Aon Corporation and Gregory C. Case - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2021.
10.40*#	Employment Agreement dated as of October 3, 2007 between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on October 3, 2007.
10.41*#	Amendment effective as of March 27, 2012 to Employment Agreement between Aon Corporation and Christa Davies dated as of October 3, 2007 - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on March 30, 2012.
10.42*#	Amendment to Employment Agreement, dated February 20, 2015, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on February 26, 2015.
10.43*#	Amendment to Employment Agreement, dated April 19, 2018, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on April 25, 2018.
10.44*#	Amendment to Employment Agreement, dated July 26, 2021, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K filed on July 26, 2021.
10.45*#	International Assignment Letter, effective July 1, 2016, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2016
10.46*#	Amendment to International Assignment Letter, dated June 25, 2018, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on June 27, 2018.
10.47*#	Amendment to International Assignment Letter, dated June 25, 2019, between Aon Corporation and Christa Davies, incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed on June 25, 2019.
10.48*#	Amendment to International Assignment Letter, dated June 19, 2020, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed June 25, 2020.
10.49*#	Amendment to International Assignment Letter, dated July 8, 2021, between Aon Corporation and Christa Davies - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2021.
10.50#	Letter Agreement, dated July 16, 2019, between Aon Corporation and Darren Zeidel.
10.51#	Letter Agreement, dated October 22, 2019, between Aon Corporation and Lisa Stevens.

108

10.52*#	Letter Agreement, dated May 11, 2018, by and between Aon Corporation and Eric Andersen- incorporated by reference to Exhibit 10.3 to Aon’s Current Report on Form 8-K filed on May 15, 2018.
10.53*#	Employment Letter, dated November 6, 2018, between Aon Corporation and John Bruno - incorporated by reference to Exhibit 10.51 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.
10.54*#	Transition and Separation Agreement, dated April 27, 2021, between Aon Corporation and John Bruno - incorporated by reference to Exhibit 10.3 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2021.
10.55*#	Consent to Shared-Sacrifice Reduction in Salary, dated April 23, 2020, between Aon plc and Gregory C. Case - incorporated by reference to Exhibit 10.6 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
10.56*#	Consent to Shared-Sacrifice Reduction in Salary, dated April 23, 2020, between Aon plc and Christa Davies - incorporated by reference to Exhibit 10.7 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
10.57*#	Consent to Shared-Sacrifice Reduction in Salary, dated April 23, 2020, between Aon plc and Eric Andersen - incorporated by reference to Exhibit 10.8 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
10.58*#	Consent to Shared-Sacrifice Reduction in Salary, dated April 23, 2020, between Aon plc and John Bruno - incorporated by reference to Exhibit 10.9 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020.
10.59*#	Amended and Restated Aon Deferred Compensation Plan, dated November 16, 2016 - incorporated by reference to the Annual Report on Form 10-K for the year ended December 31, 2016.
10.60*#	First Amendment to the Aon Deferred Compensation Plan, effective December 8, 2016, incorporated by reference to the Annual Report on Form 10-K for the year ended December 31, 2016.
10.61*#	Second Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective April 19, 2017 - incorporated by reference to Exhibit 10.1 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2017.
10.62*#	Third Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective December 27, 2019 - incorporated by referenced to Exhibit 10.51 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2019.
10.63*#	Fourth Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective May 7, 2020 - incorporated by reference to Exhibit 10.60 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.
10.64#	Fifth Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective October 1, 2021.
10.65*#	Aon plc Global Share Purchase Plan, amended and restated effective January 1, 2021 - incorporated by reference to Exhibit 10.61 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.
10.66*#	Form of Restricted Stock Unit Award Agreement, incorporated by reference to Exhibit 10.51 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2016.
10.67*#	Form of Restricted Stock Unit Agreement, incorporated by reference to Exhibit 10.2 to Aon’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2019.
10.68*#	Aon Supplemental Savings Plan, amended and restated effective January 1, 2017, incorporated by reference to Exhibit 10.52 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2016.
10.69*#	First Amendment to the Aon Supplemental Savings Plan, effective March 30, 2017, incorporated by reference to Exhibit 10.52 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2017.
10.70*#	Second Amendment to the Aon Supplemental Savings Plan, effective December 31, 2018 - incorporated by reference to Exhibit 10.58 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2019.
10.71*#	Third Amendment to the Aon Supplemental Savings Plan, effective December 27, 2019 - incorporated by reference to Exhibit 10.59 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2019.
10.72*#	Fourth Amendment to the Aon Supplemental Savings Plan, effective May 1, 2020 - incorporated by reference to Exhibit 10.68 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.

109

	10.73*#	Fifth Amendment to the Aon Supplemental Savings Plan, effective January 1, 2021 – incorporated by reference to Exhibit 10.69 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.
	10.74#	Sixth Amendment to the Aon Supplemental Savings Plan, effective October 1, 2021
	10.75*#	Aon Corporation Excess Benefit Plan (as amended and restated, effective January 1, 2009) and the following amendments thereto: First Amendment, dated January 1, 2009, Second Amendment, dated December 16, 2009, Third Amendment, dated December 31, 2018, and Fourth Amendment, dated December 27, 2019 - incorporated by reference to Exhibit 10.60 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2019.
	10.76*#	Master Assignment, Assumption and Amendment Deed to Change in Control Arrangements of Aon plc, dated April 1, 2020 - incorporated by reference to Exhibit 10.2 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
	10.77*#	Master Amendment to the Remaining Plans, dated April 1, 2020, of Aon Corporation - incorporated by reference to Exhibit 10.3 to Aon’s Current Report on Form 8-K12B filed April 1, 2020.
	10.78*	Form of Irrevocable Director Undertaking - incorporated by reference to Exhibit 10.1 to Aon’s Form 8-K filed March 10, 2020.
	10.79*#	Form of Acknowledgment of Tax Equalization Process Letter Agreement with Non-Employee Directors - incorporated by reference to Exhibit 10.74 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2020.
	10.80*	Termination Agreement, dated July 26, 2021, between Aon plc and WTW - incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed July 26, 2021.
	10.81*#	Transition and Separation Agreement, dated July 27, 2021, between Anthony R. Goland and Aon Corporation - incorporated by reference to Exhibit 10.5 to Aon’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2021.
Subsidiaries of the Registrant.
	21.1	List of Subsidiaries of Aon.
Subsidiary Guarantors and Issuers of Guaranteed Securities and Affiliates Whose Securities Collateralize Securities of the Registrant
	22.1	Subsidiary Guarantors and Issuers of Guaranteed Securities
Consents of Experts and Counsel.
	23	Consent of Ernst & Young LLP.
Rule 13a-14(a)/15d-14(a) Certifications.
	31.1.	Rule 13a-14(a) Certification of Chief Executive Officer of Aon in accordance with Section 302 of the Sarbanes-Oxley Act of 2002.
	31.2.	Rule 13a-14(a) Certification of Chief Financial Officer of Aon in accordance with Section 302 of the Sarbanes-Oxley Act of 2002.

110

Section 1350 Certifications.
	32.1.	Section 1350 Certification of Chief Executive Officer of Aon in accordance with Section 906 of the Sarbanes-Oxley Act of 2002.
	32.2.	Section 1350 Certification of Chief Financial Officer of Aon in accordance with Section 906 of the Sarbanes-Oxley Act of 2002.
XBRL Exhibits.
Interactive Data Files. The following materials are filed electronically with this Annual Report on Form 10-K:
	101.SCH	Inline XBRL Taxonomy Extension Schema Document.
	101.CAL	Inline XBRL Taxonomy Calculation Linkbase Document.
	101.DEF	Inline XBRL Taxonomy Definition Linkbase Document.
	101.PRE	Inline XBRL Taxonomy Presentation Linkbase Document.
	101.LAB	Inline XBRL Taxonomy Calculation Linkbase Document.
	104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)*

*    Document has been previously filed with the SEC and is incorporated herein by reference herein. Unless otherwise indicated, such document was filed under Commission File Number 001-07933.

#    Indicates a management contract or compensatory plan or arrangement.

The registrant agrees to furnish to the SEC upon request a copy of (1) any long-term debt instruments that have been omitted pursuant to Item 601(b)(4)(iii)(A) of Regulation S-K, and (2) any schedules omitted with respect to any material plan of acquisition, reorganization, arrangement, liquidation or succession set forth above.

Item16.    Form 10-K Summary

None.

111

SIGNATURES

        Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

		Aon plc
		By:	/s/ GREGORY C. CASE
			Gregory C. Case, Chief Executive Officer
Date:	February 18, 2022

    Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Signature	Title	Date
/s/ GREGORY C. CASE	Chief Executive Officer and Director (Principal Executive Officer)	February 18, 2022
Gregory C. Case
/s/ LESTER B. KNIGHT	Non-Executive Chairman and Director	February 18, 2022
Lester B. Knight
/s/ JIN-YONG CAI	Director	February 18, 2022
Jin-Yong Cai
/s/ JEFFREY C. CAMPBELL	Director	February 18, 2022
Jeffrey C. Campbell
/s/ FULVIO CONTI	Director	February 18, 2022
Fulvio Conti
/s/ CHERYL A. FRANCIS	Director	February 18, 2022
Cheryl A. Francis
/s/ J. MICHAEL LOSH	Director	February 18, 2022
J. Michael Losh
/s/ RICHARD B. MYERS	Director	February 18, 2022
Richard B. Myers
/s/ RICHARD C. NOTEBAERT	Director	February 18, 2022
Richard C. Notebaert
/s/ GLORIA SANTONA	Director	February 18, 2022
Gloria Santona
/s/ BYRON SPRUELL	Director	February 18, 2022
Byron Spruell
/s/ CAROLYN Y. WOO	Director	February 18, 2022
Carolyn Y. Woo
/s/ CHRISTA DAVIES	Chief Financial Officer (Principal Financial Officer)	February 18, 2022
Christa Davies
/s/ MICHAEL NELLER	Global Controller (Principal Accounting Officer)	February 18, 2022
Michael Neller

112

EX-10.20

Table of Contents

Performance Award Certificate	3
Appendix A	4
Appendix B-1	9
Appendix B-2	14
Appendix B-3	22
Appendix C	26
LPP Plan Document	53
LPP Goals and Payout Scales For 2021-2023 LPP	60

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LPP 2021-202

LEADERSHIP PERFORMANCE PROGRAM

PERFORMANCE AWARD CERTIFICATE

In Connection with the Performance Cycle

January 1, 2021 through December 31, 2023

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LPP 2021-202

APPENDIX A

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE
In Connection with Performance Cycle
January 1, 2021 through December 31, 2023

The following terms and conditions apply to all Participants unless otherwise noted herein or in Appendices B or C.

1.Governing Law. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to Appendix B to this Agreement, and the rights and obligations of the parties thereunder, shall be governed by and construed in accordance with the substantive internal laws of the State of Illinois, without regard to the conflict of law principles, rules or statutes of any jurisdiction. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to all other Sections of this Agreement, and the rights and obligations of the parties hereunder, shall be governed by and construed in accordance with the substantive internal laws of the State of Delaware, without regard to the conflict of law principles, rules or statutes of any jurisdiction. The foregoing provisions of this Section 1 shall apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may be governed by the laws of another jurisdiction (if any).

2.Venue and Jurisdiction. Venue for any legal proceedings instituted related to this Agreement shall be exclusively in the state and/or federal courts located in Cook County, Illinois, and the Participant hereby knowingly, voluntarily and irrevocably agrees, consents and submits to the exclusive jurisdiction and venue of such courts within the State of Illinois. The Participant further hereby knowingly, voluntarily and irrevocably waives, and agrees not to assert, any objection, challenge or defense to such exclusive venue or jurisdiction (including without limitation any defense of forum non conveniens), and further agrees not to file any claim or action related to this Agreement in any other jurisdiction or venue. The foregoing provisions of this Section 2 shall apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may provide for or permit venue or jurisdiction with respect to such other restrictive covenant in any other court or forum (if any). The foregoing provisions of this Section 2 shall not apply to a Participant who resides in California.

3.No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding the Participant’s participation in the Program, or the acquisition or sale of Ordinary Shares. The Participant should consult with the Participant’s own personal tax, legal and financial advisors regarding the Participant’s participation in the Program and execution of this Agreement, before executing this Agreement or otherwise taking any action at any time related to the Program.

4.Waiver; Section Headings. Waiver of any term or condition of this Agreement by any party shall not be construed as a waiver of a subsequent breach or failure of the same term or condition, or a waiver of any other term or condition of this Agreement. Any waiver must be in writing.

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The section headings in this Agreement are for convenience only and are not to be used in interpreting this Agreement.

5.Severability. To the extent that the terms set forth in this Agreement or any word, phrase, clause or sentence is found to be illegal or unenforceable by a court of competent jurisdiction for any reason, such term, word, phrase, clause or sentence shall be modified in such manner so as to afford the Company the fullest protection commensurate with making this Agreement, as modified, legal and enforceable under applicable laws. If, however, a court of competent jurisdiction finds that any such term, word, phrase, clause or sentence cannot be so modified and thus made enforceable, or otherwise declines for any reason to do so, such term, word, phrase, clause or sentence shall be deemed severed from this Agreement and of no force and effect, and the balance of this Agreement shall not be affected thereby, the balance being construed as severable and independent. The foregoing provisions of this Section 5 shall not apply to a Participant who resides in California.

6.Intellectual Property. The Participant hereby assigns to the Company the Participant’s entire right, title and interest in and to all discoveries and improvements, patentable or otherwise, trade secrets and ideas and writings and copyrightable material, which are conceived, developed, reduced to practice, or acquired by the Participant (collectively, “IP”) during the Participant’s employment and which relate to the business of the Company or any of its Affiliates, parent companies or Subsidiaries. The Participant further acknowledges that all original works of authorship which are made by the Participant (solely or jointly with others) within the scope of and during the period of his/her employment with the Company and which are protectable by copyright are “works made for hire,” as that term is defined in the United States Copyright Act. The Participant agrees to disclose promptly, fully and in writing all such IP to the Company. The Participant will upon the Company’s request, execute, acknowledge and deliver to the Company all instruments and do all other acts which are necessary or desirable to enable the Company or any of its Affiliates, parent companies, or Subsidiaries to file and prosecute applications for, and to acquire, maintain and enforce, all patents, trademarks, and copyrights in all countries. To the extent the Participant is bound by an employee handbook or contract provision that protects the Company’s intellectual property at least to the extent provided in this Section 6, the provision set forth in such employment handbook or contractual arrangement between the Participant and the Company will prevail and govern.

7.Incentive Repayment Policy. If the Participant has been designated and notified by the board of directors of the Company that the Participant is a reporting officer for purposes of Section 16 of the Exchange Act, the Participant is subject to Aon’s Incentive Repayment Policy (the “Policy”). The Policy provides that the Company will have the discretion to cancel or require reimbursement to the Company of the Award set forth in this Agreement if the grant or vesting was based on the achievement of financial results that were subsequently restated. The Participant can obtain a copy of the Policy from the Company’s Global Compensation team. If the Participant is subject to the Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by it. Notwithstanding the foregoing, to the extent the Participant is bound by an employee handbook or contract provision that protects the Company’s intellectual

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LPP 2021-202

property at least to the extent provided in this Section 7, the provision set forth in such employment handbook or contractual arrangement between the Participant and the Company will prevail and govern.

8.Compliance with Law. Notwithstanding any other provision of the Program or this Agreement, unless there is an available exemption from any registration, qualification or other legal requirement applicable to the Ordinary Shares, the Company shall not be required to deliver any Ordinary Shares issuable upon vesting/settlement of the Performance Share Units prior to the completion of any registration or qualification of the Ordinary Shares under any local, state, federal or foreign securities or exchange control law or under rulings or regulations of the U.S. Securities and Exchange Commission (“SEC”) or of any other governmental regulatory body, or prior to obtaining any approval or other clearance from any local, state, federal or foreign governmental agency, which registration, qualification or approval the Company shall, in its absolute discretion, deem necessary or advisable. The Participant understands that the Company is under no obligation to register or qualify the Ordinary Shares with the SEC or any state or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Ordinary Shares. Further, the Participant agrees that the Companyshall have unilateral authority to amend the Program and the Agreement without the Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Ordinary Shares.

9.Appendices. Notwithstanding any provision of this Agreement to the contrary, if the Participant resides in a country outside the United States or is otherwise subject to the laws of a country other than the United States, the Performance Share Units shall be subject to Appendix C to this Agreement. In addition, the terms of Appendix B-1 shall apply if the Participant resides in the United States other than in the state of California, the terms of Appendix B-2 shall apply if the Participant resides in the state of California, and the terms of Appendix B-3 shall apply if the Participant permanently resides in (or is otherwise remunerated through the local payroll of) a country outside the United States. Moreover, if the Participant relocates to one of the countries included in Appendix C, the special terms and conditions for such country will apply to the Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons.

10.Imposition of Other Requirements. The Company reserves the right to impose other requirements on the Participant’s participation in the Program, on the Performance Share Units and on any Ordinary Shares acquired under the Program, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require the Participant to sign or accept any additional agreements or undertakings that may be necessary to accomplish the foregoing.

11.Data Privacy.

The Participant is hereby notified of the collection, use and transfer, in electronic or other form, of the Participant’s personal data as described in this Agreement, any other Performance Share Units grant materials and the Company’s or, where applicable, the Employer’s

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applicable employee Privacy Notice. Such personal data may be collected, used and transferred by and among, as applicable, the Company, the Employer, any other Subsidiary or Affiliate and any third parties assisting (presently or in the future) with the implementation, administration and management of the Program, such as Fidelity Stock Plan Services, LLC (“Fidelity”) or its successor for the exclusive purpose of implementing, administering and managing the Participant’s participation in the Program. Where required under applicable law, personal data also may be disclosed to certain securities or other regulatory authorities where the Company’s shares are listed or traded or regulatory filings are made, or to certain tax authorities for compliance with the Company’s, the Employer’s and/or the Participant’s tax obligations. The Participant understands that the collection, use and transfer of the Participant’s personal data is mandatory for compliance with applicable law and necessary for the performance of the Program and that the Participant’s refusal to provide such personal data would make it impossible for the Company to perform its contractual obligations and may affect the Participant’s ability to participate in the Program.

12.Tax Withholding Obligations. The Participant acknowledges that, regardless of any action taken by the Company and/or the Employer, the ultimate liability for all income tax, social insurance contributions, payroll tax, payments on account or other tax-related items related to the Participant’s participation in the Program and legally applicable or deemed applicable to the Participant (“Tax-Related Items”), is and remains the Participant’s responsibility and may exceed the amount, if any, actually withheld by the Company or the Employer. The Participant further acknowledges that the Company and/or the Employer: (a) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the grant of Performance Share Units or the underlying Shares, including, but not limited to, the grant, vesting or settlement of the Performance Share Units, the issuance of Ordinary Shares upon settlement of the Performance Share Units, the subsequent sale of Ordinary Shares acquired pursuant to such vesting/settlement and the receipt of any dividends and/or dividend equivalents; and (b) do not commit to and are under no obligation to structure the terms of the Award or any aspect of the Performance Share Units to reduce or eliminate the Participant’s liability for Tax-Related Items or achieve any particular tax result. Further, if the Participant is subject to Tax-Related Items in more than one jurisdiction, the Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction.

a)Prior to any relevant taxable or tax withholding event, as applicable, the Participant agrees to make adequate arrangements satisfactory to the Company or the Employer, to satisfy all Tax-Related Items. In this regard, the Participant authorises the Company and/or the Employer, or their respective agents, at the Company’s discretion, to satisfy the obligations with regard to all Tax-Related Items by one or a combination of the following: (i) withholding from any wages or other cash compensation payable to the Participant; or (ii) withholding in Ordinary Shares to be issued upon vesting/settlement of the Performance Share Units; or (iii) withholding from the proceeds of the sale of Ordinary Shares acquired upon vesting/settlement of the Performance Share Units either through a voluntary sale or through a mandatory sale arranged by the Company (on the

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Participant’s behalf pursuant to this authorisation without further consent); provided, however, that if the Participant is a Section 16 officer under the Exchange Act, as amended, the Committee shall establish the method of withholding from alternatives (i) - (iii) herein.

b)The Company and/or the Employer may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates in the Participant’s jurisdiction(s), including maximum applicable rates. If Tax-Related Items are withheld in excess of the Participant’s actual tax liability, any over-withheld amount may be refunded to the Participant in cash by the Company or the Employer (with no entitlement to the equivalent in Ordinary Shares) or, if not refunded, the Participant may seek a refund from the local tax, social security or other applicable authorities. If the obligation for Tax-Related Items is satisfied by withholding in Ordinary Shares, for tax purposes, the Participant shall be deemed to have been issued the full number of Ordinary Shares subject to the vested Performance Share Units, notwithstanding that a number of Ordinary Shares are held back solely for the purpose of paying the Tax-Related Items.

c)Finally, the Participant shall pay to the Company and/or the Employer any amount of Tax-Related Items that the Company and/or the Employer may be required to withhold as a result of the Participant’s participation in the Program that cannot be satisfied by the means previously described. The Company may refuse to deliver the Ordinary Shares or the proceeds of the sale of Ordinary Shares if the Participant fails to comply with the Participant’s obligations in connection with the Tax-Related Items.

d)Notwithstanding anything in this Section 12 to the contrary, to avoid a prohibited distribution under Code Section 409A in the case of a Participant who is subject to U.S. federal income tax (a “U.S. Taxpayer”), if Ordinary Shares underlying the Performance Share Units will be withheld (or sold on the Participant’s behalf) to satisfy any Tax-Related Items arising prior to the date of settlement of the Performance Share Units for any portion of the Performance Share Units that is considered “nonqualified deferred compensation” subject to Code Section 409A, then the number of Ordinary Shares withheld (or sold on the Participant’s behalf) shall not exceed the number of Ordinary Shares that equals the liability for the Tax-Related Items.

13.Language. The Participant acknowledges that the Participant is proficient in the English language, or has consulted with an advisor who is proficient in English, so as to enable the Participant to understand the provisions of this Agreement and the Program. If the Participant has received this Agreement or any other document related to the Program translated into a language other than English, and if the meaning of the translated version is different than the English version, the English version will control.

14.Insider Trading Restrictions/Market Abuse Laws. The Participant may be subject to insider trading restrictions and/or market abuse laws based on the exchange on which the Ordinary Shares are listed and in applicable jurisdictions, including the United States, the Participant’s

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country or the designated broker’s country, which may affect the Participant’s ability to accept, acquire, sell or otherwise dispose of Ordinary Shares, rights to Ordinary Shares (e.g., Performance Share Units) or rights linked to the value of Ordinary Shares (e.g., dividend equivalents) under the Program during such times as the Participant is considered to have “inside information” regarding the Company (as defined by the laws in applicable jurisdictions). Local insider trading laws and regulations may prohibit the cancellation or amendment of orders the Participant placed before the Participant possessed inside information. Furthermore, the Participant could be prohibited from (i) disclosing the inside information to any third party, including fellow employees and (ii) “tipping” third parties or causing them otherwise to buy or sell securities. Any restrictions under these laws or regulations are separate from and in addition to any restrictions that may be imposed under any applicable insider trading policy of the Company. The Participant acknowledges that it is the Participant’s responsibility to comply with any applicable restrictions, and the Participant should speak to the Participant’s personal advisor on this matter.

15.Exchange Control, Foreign Asset/Account and/or Tax Reporting. Depending upon the country to which laws the Participant is subject, the Participant may have certain foreign asset/account and/or tax reporting requirements that may affect the Participant’s ability to acquire or hold Ordinary Shares under the Program or cash received from participating in the Program (including from any dividends or dividend equivalents or sale proceeds arising from the sale of Ordinary Shares) in a brokerage or bank account outside the Participant’s country of residence. The Participant’s country may require that the Participant report such accounts, assets or transactions to the applicable authorities in the Participant’s country. The Participant also may be required to repatriate cash received from participating in the Program to the Participant’s country within a certain period of time after receipt. The Participant is responsible for knowledge of and compliance with any such regulations and should speak with the Participant’s own personal tax, legal and financial advisors regarding same.

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APPENDIX B-1

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE FOR U.S. (NON-CALIFORNIA) PARTICIPANTS
In Connection with the Performance Cycle
January 1, 2021 through December 31, 2023

The following provisions shall apply to Participants who reside in the United States, other than in the state of California.

1.Business Considerations; Restrictive Covenants; Acknowledgments; Injunctive Relief; Confidential Information.

a)Business Considerations. Aon plc and its Subsidiary, Aon Corporation, a Delaware corporation with its corporate and business headquarters in Chicago, Illinois, and Aon Corporation’s Subsidiaries and Affiliates (and divisions thereof) (collectively, with Aon plc, “Aon”) are in the business of providing conventional and alternative risk management products and services covering the businesses of insurance brokerage, reinsurance brokerage, benefits consulting, compensation consulting, human resources consulting, human resources and benefits outsourcing, management, investigatory and security consulting, retirement and investment consulting, managing underwriting and related services, including accounting, actuarial, claims management and handling, and information systems on behalf of commercial and individual clients which are national and international and are not confined to any geographic area (the “Business”). The Participant further acknowledges that the Participant’s material employment duties and responsibilities, including without limitation with respect to Aon clients, prospective clients, referral sources and other employees, span geographic areas that extend well beyond the state in which the Participant is physically employed and resides. An essential element of the Business is the development and maintenance of personal contacts and relationships with clients and prospective clients. Aon invests considerable time and money to develop and maintain client relationships and referral sources, including payment of employees’ salaries, benefits, travel, entertainment and other business expenses and assistance in servicing clients by making available to its employees specially developed and researched industry data, client-specific information, legal support, accounting support, marketing, advertising and other corporate services, as well as providing training and professional development and valuable confidential business and professional information, toward the development and maintenance of its client relationships and related goodwill. While these clients, prospective clients, and referral sources may be secured or serviced by Aon employees, including the Participant, the Participant acknowledges that such clients, prospective clients and referral sources remain at all times the clients, prospective clients and referral sources of Aon and that the goodwill engendered by the relationships is intended to inure only to the benefit of Aon; the goodwill is owned by Aon; and Aon shall be the sole beneficiary of such goodwill during and after termination of the Participant’s employment with Aon. In addition, the

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Participant acknowledges that the Participant has acquired and/or will acquire, for the purpose of furthering the Business, knowledge of Aon’s confidential and proprietary information; the Participant further acknowledges Aon’s legitimate interest in safeguarding confidential and proprietary information from disclosure.

The personal identification of clients or referral sources of Aon with an Aon employee, including the Participant, creates the potential for the Participant’s appropriation of the benefits of the relationships developed with clients and referral sources on behalf of and at the expense of Aon. Since Aon would suffer irreparable harm if the Participant left its employ and solicited the Business of the clients, prospective clients and referral sources of Aon, or solicited the employees of Aon, it is reasonable to protect Aon against certain competitive activities by the Participant for a limited period of time after the Participant leaves employment so that Aon may renew or restore its business relationship with its clients, prospective clients, referral sources and employees. Consequently, the Participant is willing to enter into the covenants set forth herein in order to provide Aon with reasonable protection for its client, prospective client, referral sources and employee relationships and its investment therein as above-described, its goodwill, and its confidential and proprietary information.

b)Covenant Not to Solicit Clients and Prospective Clients. The Participant hereby covenants and agrees that, except with the prior written consent of Aon, the Participant (on the Participant’s own behalf or on behalf of any other person or entity) will not, during the course of employment, and for a period of two years after the Participant’s Termination Date (the “Restricted Period”), directly or indirectly, call upon, solicit, accept, engage in, service or perform, other than on behalf of Aon, any business of the same type or kind as the Business performed by Aon from or with respect to (i) clients of Aon with respect to whom the Participant provided services, either alone or with others, or had a business relationship, or on whose account the Participant worked or became familiar, or supervised directly or indirectly the servicing activities related to such clients, during the 24 months prior to the Participant’s Termination Date (or such shorter time as Participant was employed) (“Look Back Period”) and, further provided, such clients were clients of Aon either on the Participant’s Termination Date or within 12 months prior to such Termination Date and (ii) prospective clients of Aon which the Participant alone, in combination with others, or in a supervisory capacity, solicited during the six months prior to the Participant’s Termination Date and to which a proposal for services was rendered by Aon during the six months prior to the Participant’s Termination Date. “Client” means any person or entity listed on the books of Aon as such, or any majority owned subsidiary of a person or entity listed on the books of Aon as a client. “Solicit” is understood to include any direct or indirect interaction between the Participant and another person or entity that takes place in an effort to develop or further a business relationship, irrespective of which party first initiates contact, and expressly includes notifying a client that the Participant has left Aon’s employ to go to another company.

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c)Covenant Not to Solicit Employees. The Participant hereby also agrees, for the duration of the Restricted Period, not to, directly or indirectly, hire, solicit or induce, or cause any person or other entity to solicit or induce, any employee of Aon with whom the Participant had material contact or about whom the Participant had access to Confidential Information during the twenty-four (24) months prior to the Participant’s termination of employment to work for the Participant or for any third party or entity, or to leave the employ of Aon.

d)Covenant Not to Solicit Referral Sources. The Participant hereby covenants and agrees that, except with the prior written consent of Aon, the Participant (on the Participant’s own behalf or on behalf of any other person or entity) will not, during the Restricted Period, directly or indirectly, call upon, solicit, accept, engage in, service, other than on behalf of Aon, any business of the same type or kind as the business performed by Aon from or with respect to Referral Sources. "Referral Sources" means each and every entity from whom Aon has received referrals with regard to its products and services at any time during the Look Back Period, and about whom Participant had gained Confidential Information or with whom Participant had material contact during the Look Back Period; and (ii) each and every entity that is a source of referrals for business and to whom Participant submitted or assisted in a proposal for services, or otherwise solicited or assisted in the solicitation of referrals from such entity, at any time during the Look Back Period.

e)Other Covenants. Notwithstanding any other language in the Agreement, this Agreement does not preclude the enforceability of any restrictive covenant provision contained in any prior or subsequent agreement entered into by the Participant, (any such covenant, an “Other Covenant”), including without limitation any covenant contained in any Confidentiality and Non-Solicitation Agreement between the Participant and any Aon entity, and further including without limitation any covenant not to compete, to solicit or perform services for clients, or to solicit employees, any confidentiality or intellectual property covenant, and any covenant with respect to a pre-resignation notice period. Further, no Other Covenant precludes the enforceability of any provision contained in this Agreement. No subsequent agreement entered into by the Participant may amend, supersede, or override the covenants contained herein unless such subsequent agreement specifically references subsections (b), (c) and (d) of this Section.

f)Acknowledgments. Aon and the Participant acknowledge and agree that the covenants contained in subsections (b), (c) and (d) of this Section are necessary and reasonable for the protection of Aon and are reasonably limited with respect to the activities prohibited, duration, geographical scope and their effect on the Participant and the public. The parties acknowledge that the purpose and effect of the covenants simply are to protect Aon for a limited period of time from unfair competition by the Participant.

The Participant acknowledges that there is no general geographical restriction contained in the preceding paragraphs because the restrictions apply only to the specified clients of

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Aon and because the Participant’s material duties, responsibilities, and relationships with Aon clients, prospective clients, and employees are not limited to any particular geographic area. Nothing in this Agreement shall prohibit the Participant from obtaining a livelihood for the Participant or the Participant’s family by being engaged in the Business.

g)Right to Injunctive Relief; Attorneys’ Fees and Costs; Extension. The Participant acknowledges that the Participant’s services to Aon are of a unique character which gives them a special value to Aon, the loss of which cannot reasonably or adequately be compensated in damages in an action at law, and that a breach of this Section 1 will result in irreparable and continuing harm to Aon, and that therefore, in addition to any other remedy which Aon may have at law or in equity, Aon shall be entitled to temporary, preliminary and permanent injunctive relief for a breach or threatened breach of this Agreement by the Participant (without the need to post any bond or other security). The parties acknowledge and agree that each Aon entity, including the Participant’s Employer, is an intended third-party beneficiary of this Agreement, and may be a named plaintiff in any subsequent suit brought by Aon to enforce the terms of this Section 1. In the event that Aon brings an action to enforce the terms and conditions of the Agreement, the Participant shall pay the costs and expenses incurred by Aon in bringing such action, including without limitation attorneys’ and other legal fees. If Participant violates one of the post-employment restrictions in this Agreement on which there is a specific time limitation, the time period for that restriction will be extended by one day for each day Participant violates it, up to a maximum extension equal to the time period originally prescribed for the restrictions, so as to give the Company the full benefit of the bargained-for length of forbearance.

h)Trade Secrets and Confidential Information. The Participant acknowledges that Aon’s Business depends to a significant degree upon the possession of confidential, proprietary, and trade secret information which is not generally known to others, and that the profitability of such Business requires that this information remain proprietary to Aon. The Participant recognises that, by virtue of the Participant’s employment with Aon, and to assist the Participant in the solicitation, production and servicing of client Business, the Participant will be granted otherwise prohibited access to such information.

(i)This information (hereinafter referred to as “Confidential Information”) includes, without limitation, lists of clients and prospective clients; contract terms and conditions; client information relating to services, insurance, benefits programs, employees, finances, and compensation (unless the Participant’s own); copyrighted materials; corporate, management and business plans and strategies; compensation and revenues; methods and strategies of marketing; market research and data; technical know-how; computer software and manuals; policies and procedures; and the conduct of the affairs of Aon. Confidential Information does not include any information that lawfully is or has become generally or

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publicly known other than through the Participant’s breach of this Agreement or a breach by another person of some other obligation to Aon. Further, Confidential Information does not include information lawfully acquired by a non-management employee (laborer) about wages, hours or other terms and conditions of employment if used by them for purposes protected by §7 of the National Labor Relations Act (the NLRA) such as joining or forming a union, engaging in collective bargaining, or engaging in other concerted activity for their mutual aid or protection. The Participant understands that under the NLRA, covered employees have a right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection, and to refrain from any or all of such activities.

The Participant shall not, except as required in the course of employment by Aon or as otherwise provided by applicable law or in this subsection (g), disclose or use during or subsequent to the course of employment, any Confidential Information. This restriction on use or disclosure of Confidential Information will only apply for three (3) years after the end of the Participant’s employment, where information that does not qualify as a trade secret is concerned; however, the restrictions will continue to apply to trade secret information for as long as the information at issue remains qualified as a trade secret.

(ii)The Participant understands that nothing contained in this Agreement limits the Participant’s ability to report possible violations of law or regulation to, or file a charge or complaint with, the Securities and Exchange Commission, the Equal Employment Opportunity Commission, the National Labor Relations Board, the Occupational Safety and Health Administration, the Department of Justice, the Congress, any Inspector General, or any other federal, state or local governmental agency or commission (“Government Agencies”). The Participant further understands that this Agreement does not limit the Participant’s ability to participate in any investigation or proceeding that may be conducted by any Government Agency, without notice to the Company.

Nothing in this Agreement shall limit the Participant’s ability under applicable United States federal law to (i) disclose in confidence trade secrets to federal, state, and local government officials, or to an attorney, for the sole purpose of reporting or investigating a suspected violation of law or (ii) disclose trade secrets in a document filed in a lawsuit or other proceeding, but only if the filing is made under seal and protected from public disclosure.

(iii)Upon termination of employment or upon Aon’s request (whichever is earlier), the Participant will promptly return to Aon all Confidential Information and all materials and all copies or tangible embodiments of materials involving

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Confidential Information, and all other Aon property, in the Participant’s possession or control, except as otherwise provided by law or in this subsection (g). The Participant agrees to represent in writing to Aon upon termination of employment that the Participant has complied with the provisions of this subsection (g).

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APPENDIX B-2

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE FOR CALIFORNIA PARTICIPANTS
In Connection with the Performance Cycle
January 1, 2021 through December 31, 2023

The following provisions shall apply for Participants who reside in California.

1.Business Considerations; Restrictive Covenants; Acknowledgments; Injunctive Relief; Confidential Information.

a)Business Considerations. Aon plc and its Subsidiary, Aon Corporation, a Delaware corporation with its corporate and business headquarters in Chicago, Illinois, and Aon Corporation’s Subsidiaries and Affiliates (and divisions thereof) (collectively, with Aon plc, “Aon”) are in the business of providing conventional and alternative risk management products and services covering the businesses of insurance brokerage, reinsurance brokerage, benefits consulting, compensation consulting, human resources consulting, human resources and benefits outsourcing, management, investigatory and security consulting, retirement and investment consulting, managing underwriting and related services, including accounting, actuarial, claims management and handling, and information systems on behalf of commercial and individual clients which are national and international and are not confined to any geographic area (the “Business”). The Participant further acknowledges that the Participant’s material employment duties and responsibilities, including without limitation with respect to Aon clients, prospective clients, referral sources and other employees, span geographic areas that extend well beyond the state in which the Participant is physically employed and resides. An essential element of the Business is the development and maintenance of personal contacts and relationships with clients and prospective clients. Aon invests considerable time and money to develop and maintain client relationships and referral sources, including payment of employees’ salaries, benefits, travel, entertainment and other business expenses and assistance in servicing clients by making available to its employees specially developed and researched industry data, client-specific information, legal support, accounting support, marketing, advertising and other corporate services, as well as providing training and professional development and valuable confidential business and professional information, toward the development and maintenance of its client relationships and related goodwill. While these clients, prospective clients and referral sources may be secured or serviced by Aon employees, including the Participant, the Participant acknowledges that such clients, prospective clients and referral sources remain at all times the clients and prospective clients of Aon and that the goodwill engendered by the relationships is intended to inure only to the benefit of Aon; the goodwill is owned by Aon; and Aon shall be the sole beneficiary of such goodwill during and after termination of the Participant’s employment with Aon. In addition, the Participant acknowledges that the Participant has acquired and/or will acquire, for the

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purpose of furthering the Business, knowledge of Aon’s confidential and proprietary information; the Participant further acknowledges Aon’s legitimate interest in safeguarding confidential and proprietary information from disclosure.

The personal identification of clients or referral sources of Aon with an Aon employee, including the Participant, creates the potential for the Participant’s appropriation of the benefits of the relationships developed with clients and referral sources on behalf of and at the expense of Aon. Since Aon would suffer irreparable harm if the Participant left its employ and solicited the Business of the clients, prospective clients and referral sources of Aon, or solicited the employees of Aon, it is reasonable to protect Aon against certain competitive activities by the Participant for a limited period of time after the Participant leaves employment so that Aon may renew or restore its business relationship with its clients, prospective clients, referral sources and employees. Consequently, the Participant is willing to enter into the covenants set forth herein in order to provide Aon with reasonable protection for its client, prospective client, referall sources and employee relationships and its investment therein as above-described, its goodwill, and its confidential and proprietary information.

b)Covenant Not to Solicit Clients and Prospective Clients. The Participant hereby covenants and agrees that, except with the prior written consent of Aon, the Participant (on the Participant’s own behalf or on behalf of any other person or entity) will not, during the course of employment, and for a period of two years after the Participant’s Termination Date (the “Restricted Period”), directly or indirectly, call upon, solicit, accept, engage in, service or perform, other than on behalf of Aon, any business of the same type or kind as the Business performed by Aon from or with respect to (i) clients of Aon with respect to whom the Participant provided services, either alone or with others, or had a business relationship, or on whose account the Participant worked or became familiar, or supervised directly or indirectly the servicing activities related to such clients, during the 24 months prior to the Participant’s Termination Date (or such shorter time as Participant was employed) (“Look Back Period”) and, further provided, such clients were clients of Aon either on the Participant’s Termination Date or within 12 months prior to such Termination Date and (ii) prospective clients of Aon which the Participant alone, in combination with others, or in a supervisory capacity, solicited during the six months prior to the Participant’s Termination Date and to which a proposal for services was rendered by Aon during the six months prior to the Participant’s Termination Date. “Client” means any person or entity listed on the books of Aon as such. “Solicit” is understood to include any direct or indirect interaction between the Participant and another person or entity that takes place in an effort to develop or further a business relationship, irrespective of which party first initiates contact, and expressly includes notifying a client that the Participant has left Aon’s employ to go to another company.

c)Covenant Not to Solicit Employees. The Participant hereby also agrees, for the duration of the Restricted Period, not to, directly or indirectly, hire, solicit or induce, or cause any person or other entity to solicit or induce, any employee of Aon with whom the

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Participant had material contact or about whom the Participant had access to Confidential Information during the twenty-four (24) months prior to the Participant’s termination of employment to work for the Participant or for any third party or entity, or to leave the employ of Aon.

d)Covenant Not to Solicit Referral Sources. The Participant hereby covenants and agrees that, except with the prior written consent of Aon, the Participant (on the Participant’s own behalf or on behalf of any other person or entity) will not, during the Restricted Period, directly or indirectly, call upon, solicit, accept, engage in, service, other than on behalf of Aon, any business of the same type or kind as the business performed by Aon from or with respect to Referral Sources. "Referral Sources" means each and every entity from whom Aon has received referrals with regard to its products and services at any time during the Look Back Period, and about whom Participant had gained Confidential Information or with whom Participant had material contact during the Look Back Period; and (ii) each and every entity that is a source of referrals for business and to whom Participant submitted or assisted in a proposal for services, or otherwise solicited or assisted in the solicitation of referrals from such entity, at any time during the Look Back Period

e)Other Covenants. Notwithstanding any other language in the Agreement, this Agreement does not preclude the enforceability of any restrictive covenant provision contained in any prior or subsequent agreement entered into by the Participant (any such covenant, an “Other Covenant”), including without limitation any covenant contained in any Confidentiality and Non-Solicitation Agreement between the Participant and any Aon entity, and further including without limitation any covenant not to compete, to solicit or perform services for clients, or to solicit employees, any confidentiality or intellectual property covenant, and any covenant with respect to a pre-resignation notice period. Further, no Other Covenant precludes the enforceability of any provision contained in this Agreement. No subsequent agreement entered into by the Participant may amend, supersede, or override the covenants contained herein unless such subsequent agreement specifically references subsections (b), (c) and (d) of this Section.

f)Acknowledgments. Aon and the Participant acknowledge and agree that the covenants contained in subsections (b), (c) and (d) of this Section are necessary and reasonable for the protection of Aon and are reasonably limited with respect to the activities prohibited, duration, geographical scope and their effect on the Participant and the public. The parties acknowledge that the purpose and effect of the covenants simply are to protect Aon for a limited period of time from unfair competition by the Participant.

The Participant acknowledges that there is no general geographical restriction contained in the preceding paragraphs because the restrictions apply only to the specified clients of Aon and because the Participant’s material duties, responsibilities and relationships with Aon clients, prospective clients, and employees are not limited to any particular geographic area. Nothing in this Agreement shall prohibit the Participant from obtaining

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a livelihood for the Participant or the Participant’s family by being engaged in the Business.

g)Right to Injunctive Relief; Attorneys’ Fees and Costs; Extension. The Participant acknowledges that the Participant’s services to Aon are of a unique character which gives them a special value to Aon, the loss of which cannot reasonably or adequately be compensated in damages in an action at law, and that a breach of this Agreement will result in irreparable and continuing harm to Aon, and that therefore, in addition to any other remedy which Aon may have at law or in equity in an arbitration pursuant to Section 2 of this Appendix B-2 below, Aon shall be entitled to emergency, injunctive or other interim relief in an arbitration pursuant to Section 2 of this Appendix B-2 below for a breach of this Agreement by the Participant. The parties acknowledge and agree that each Aon entity is an intended third-party beneficiary of this Agreement, and may be a named plaintiff in any subsequent arbitration brought by Aon to enforce the terms of this Agreement. In the event that Aon brings an action to enforce the terms and conditions of the Agreement, the Participant shall pay the costs and expenses incurred by Aon in bringing such action, including without limitation attorneys’ and other legal fees. If Participant violates one of the post-employment restrictions in this Agreement on which there is a specific time limitation, the time period for that restriction will be extended by one day for each day Participant violates it, up to a maximum extension equal to the time period originally prescribed for the restrictions, so as to give the Company the full benefit of the bargained-for length of forbearance.

h)Trade Secrets and Confidential Information. The Participant acknowledges that Aon’s Business depends to a significant degree upon the possession of confidential, proprietary, and trade secret information which is not generally known to others, and that the profitability of such Business requires that this information remain proprietary to Aon. The Participant recognises that, by virtue of the Participant’s employment with Aon, and to assist the Participant in the solicitation, production and servicing of client Business, the Participant will be granted otherwise prohibited access to such information.

(i)This information (hereinafter referred to as “Confidential Information”) includes, without limitation, lists of clients and prospective clients; contract terms and conditions; client information relating to services, insurance, benefits programs, employees, finances, and compensation (unless the Participant’s own); copyrighted materials; corporate, management and business plans and strategies; compensation and revenues; methods and strategies of marketing; market research and data; technical know-how; computer software and manuals; policies and procedures; and the conduct of the affairs of Aon. Confidential Information does not include any information that lawfully is or has become generally or publicly known other than through the Participant’s breach of this Agreement or a breach by another person of some other obligation to Aon. Further, Confidential Information does not include information lawfully acquired by a non-management employee (laborer) about wages, hours or other terms and

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conditions of employment if used by them for purposes protected by §7 of the National Labor Relations Act (the NLRA) such as joining or forming a union, engaging in collective bargaining, or engaging in other concerted activity for their mutual aid or protection. The Participant understands that under the NLRA, covered employees have a right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection, and to refrain from any or all of such activities.

The Participant shall not, except as required in the course of employment by Aon or as otherwise provided by applicable law or in this subsection (g), disclose or use during or subsequent to the course of employment, any Confidential Information. This restriction on use or disclosure of Confidential Information will only apply for three (3) years after the end of the Participant’s employment, where information that does not qualify as a trade secret is concerned; however, the restrictions will continue to apply to trade secret information for as long as the information at issue remains qualified as a trade secret.

(ii)The Participant understands that nothing contained in this Agreement limits the Participant’s ability to report possible violations of law or regulation to, or file a charge or complaint with, the Securities and Exchange Commission, the Equal Employment Opportunity Commission, the National Labor Relations Board, the Occupational Safety and Health Administration, the Department of Justice, the Congress, any Inspector General, or any other federal, state or local governmental agency or commission (“Government Agencies”). The Participant further understands that this Agreement does not limit the Participant’s ability to participate in any investigation or proceeding that may be conducted by any Government Agency, without notice to the Company.

Nothing in this Agreement shall limit the Participant’s ability under applicable United States federal law to (i) disclose in confidence trade secrets to federal, state, and local government officials, or to an attorney, for the sole purpose of reporting or investigating a suspected violation of law or (ii) disclose trade secrets in a document filed in a lawsuit or other proceeding, but only if the filing is made under seal and protected from public disclosure.

(iii)Upon termination of employment or upon Aon’s request (whichever is earlier), the Participant will promptly return to Aon all Confidential Information and all materials and all copies or tangible embodiments of materials involving Confidential Information, and all other Aon property, in the Participant’s possession or control, except as otherwise provided by law or in this subsection (g). The Participant agrees to represent in writing to Aon upon termination of

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employment that the Participant has complied with the provisions of this subsection (g).

2.Arbitration

a)The Participant and the Company (including on behalf of Aon Corporation) agree that, to the maximum extent permitted by law, all claims or disputes between or involving the Participant and Aon (including without limitation any subsidiary of the Company) (i) arising under or relating to Sections 1 and 2 of this Appendix B-2 or any Other Covenant, or (ii) involving the interpretation, applicability, enforceability or formation of Sections 1 and 2 of this Appendix B-2, any Other Covenant, or any portion thereof (including without limitation the agreement to arbitrate in this Section 2, and further including without limitation any claim or dispute alleging that Sections 1 and 2 of this Appendix B-2, any Other Covenant, or any portion thereof is a contract of adhesion, lacks consideration, is substantively or procedurally unconscionable, is void against public policy, or otherwise is void or voidable for any reason), shall be determined and resolved exclusively by arbitration in Chicago, Illinois (or such other location to which the Participant and the Company may agree) before a single neutral arbitrator (which may include, as provided below, a single neutral Emergency Arbitrator (defined below) and then a single neutral regular arbitrator), in compliance with and as further provided in this Section. Any and all such claims and disputes shall be brought solely in a party’s individual capacity and not as a claimant or class member (or similar capacity) in any purported multiple-claimant, class, collective, representative or other similar proceeding, except as otherwise required by law. Unless otherwise indicated in this Section expressly or by context, the term “arbitrator” means an Emergency Arbitrator and/or a regular arbitrator.

b)The arbitrator shall have the authority to make any award or impose any remedy that is available to a court of general jurisdiction sitting in Chicago, Illinois and that was requested by a party to the claim or dispute, including without limitation the authority to award emergency, injunctive or other interim relief pending the conducting of the arbitration on the merits and the rendering of a final award, whether styled as a temporary or preliminary injunction or otherwise (collectively, “Interim Arbitral Relief”). The arbitrator shall not have the authority to make an award or impose a remedy that is not available to such a court or is not requested by such a party, and the jurisdiction of the arbitrator is limited accordingly. For avoidance of doubt, the parties hereby acknowledge and agree that the Company (including Aon Corporation) or the Participant may assert a claim or dispute encompassed by this Section, and seek a remedy or relief for or associated with such claim or dispute (including without limitation emergency, injunctive or other interim relief, or final relief) only in arbitration pursuant to this Section, and may not pursue an action in court for or relating to any such claim, dispute, remedy or relief, other than as provided in Section 2(h) of this Appendix B-2 below solely for the purpose of entering judgment enforcing an interim or final arbitration award.

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c)If a party seeks Interim Arbitral Relief, including without limitation to enforce any covenant in Section 1 of this Appendix B-2 or Other Covenant, the arbitration of such Interim Arbitral Relief request shall be administered by JAMS’ Chicago, Illinois office and conducted in accordance with the Emergency Relief Procedures set forth in Section 2(c) of the JAMS Comprehensive Arbitration Rules & Procedures (as in effect or amended from time to time, or any successor provision thereto) (hereafter, the “Emergency Relief Procedures” and the “Comprehensive Rules,” respectively), except as otherwise provided (whether or not by reference to specific Rules) in this Section. During the first thirty-six (36) hours after the filing with JAMS and service of the party’s Interim Arbitral Relief request (or, if earlier, the first thirty-six (36) hours after the party’s notification (whether or not in writing) to the other party of such request), the parties shall make good faith efforts to confer and to agree upon an arbitrator to hear and decide such Interim Arbitral Relief request (the “Emergency Arbitrator”). If, by the end of such thirty-six (36) hour period (or such longer period to which the parties may agree), the parties are unable to so confer or otherwise do not reach agreement on an Emergency Arbitrator, or the respondent to the Interim Arbitral Relief request does not respond to or cooperate in such Emergency Arbitrator selection efforts, the Emergency Arbitrator shall be selected by JAMS’ Chicago, Illinois office in accordance with the Emergency Relief Procedures and this Section.

d)If a party demands arbitration and does not seek Interim Arbitral Relief, or if a request for Interim Arbitral Relief has been withdrawn, decided or otherwise resolved (whether by agreement, by an interim award by the Emergency Arbitrator, or otherwise) and the arbitration of the claim or dispute proceeds thereafter, such arbitration shall be administered by JAMS’ Chicago, Illinois office and conducted in accordance with the Comprehensive Rules, except as otherwise provided (whether or not by reference to specific Rules) in this Section. The parties expressly are not agreeing to the following Rules (or amended or successor rules thereof) within the Comprehensive Rules, which shall not apply to any arbitration under this Section 2 (whether or not seeking Interim Arbitral Relief): Rule 16.1 (Application of Expedited Procedures), Rule 32 (Bracketed (or High-Low) Arbitration Option), Rule 33 (Final Offer (or Baseball) Arbitration Option), and Rule 34 (Optional Arbitration Appeal Procedure). Unless the parties otherwise agree to the selection of an arbitrator for such arbitration (which may be the Emergency Arbitrator if the parties and JAMS so agree, or another arbitrator), the arbitrator shall be selected by JAMS’ Chicago, Illinois office in accordance with the Comprehensive Rules and this Section.

e)In selecting an Emergency Arbitrator and/or regular arbitrator (as applicable), JAMS shall select and assign an arbitrator from JAMS’ Chicago, Illinois arbitrator roster who shall have reasonably substantial experience in litigating or arbitrating restrictive covenant disputes or, if such arbitrator is not then available, shall select and assign an arbitrator from JAMS’ Chicago, Illinois arbitrator roster who shall have reasonably substantial experience as a judge presiding over civil litigation matters in a general civil litigation division (including a general law division or general chancery division) of a

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federal or state court. Unless the parties otherwise agree, any arbitrator selected pursuant to this Section (whether selected by the parties or by JAMS) shall be based in and reside in the Chicago, Illinois metropolitan area.

f)The arbitrator shall have no power to modify the provisions of this Agreement (except pursuant to Section 4 of this Appendix B-2 below), and furthermore, notwithstanding any other provision of this Agreement, in no event may the arbitrator consolidate or allow any party to join any claims of any other employee or person in a single arbitration proceeding (whether as a multiple-claimant, class, collective, representative or other similar proceeding) without the express written consent of the Company and the Participant (except as otherwise required by law), and in each case the jurisdiction of the arbitrator is limited accordingly. The arbitrator shall apply the substantive internal law of the State of Illinois, including applicable statutes of limitation, except as otherwise required by law or provided in this Section, and provided further (for avoidance of doubt) that privileges and other immunities from discovery or disclosure (including without limitation the attorney-client privilege and the work product doctrine) shall be governed by, and the arbitrator shall apply to such issues, federal law (including without limitation Rules 26(b)(3), (4) and (5) of the Federal Rules of Civil Procedure (as in effect or amended from time to time) and the attorney-client privilege as articulated in Upjohn Co. v. United States, 449 U.S. 383 (1981) and its progeny, but excluding any choice of law rules or principles (e.g., Federal Rule of Evidence 501) that might otherwise cause state law, or some other law besides federal law, to govern the attorney-client privilege or work product doctrine). Each party to the arbitration is entitled to be represented by legal counsel of such party’s choosing. The Company shall pay the fees and costs of the arbitrator and of JAMS (including case administration, hearing room and hearing transcription fees), but each party shall be responsible for such party’s own attorneys’ fees and related arbitration costs and expenses except to the extent otherwise allocated by the arbitrator in accordance with the applicable Emergency Relief Procedures or Comprehensive Rules and Section 1(f) of this Appendix B-2 above.

g)Adequate discovery and an opportunity to be heard and to present evidence will be permitted by the arbitrator consistent with applicable law and the objectives of arbitration, provided, however, that the parties expressly are not agreeing to Rules 17(a), 17(b) or 17(c) (or amended or successor rules thereof) within the Comprehensive Rules (Exchange of Information), which shall not apply to any arbitration under this Section (whether or not seeking Interim Arbitral Relief). The parties may serve interrogatories, document requests and requests for admission, and take depositions, as provided by and in accordance with the Federal Rules of Civil Procedure (as in effect or amended from time to time), including without limitation any limitations on discovery provided therein, except as otherwise ordered by the arbitrator following motion of a party or as agreed to by the parties. Disclosures with respect to any expert witnesses shall be made as provided by and in accordance with Rule 26(a)(2) (except subpart (D) thereof) of the Federal Rules of Civil Procedure (as in effect or amended from time to time). The timing of discovery and any such disclosures (including without limitation any prehearing

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disclosures) shall be determined by the arbitrator in accordance with the Comprehensive Rules or as agreed to by the parties. Each party shall have the right to file a Motion (or Motions) for Summary Disposition of any given claim(s) or issue(s), which shall be considered and ruled upon by the arbitrator.

h)The arbitrator’s decision or award (whether an interim decision or award based on a request for Interim Arbitral Relief or a final decision or award deciding or resolving the claim or dispute), shall be in writing summarizing the basis therefor and shall be final and binding, and judgment thereupon may be entered in any Illinois federal or state court.

i)Any arbitration conducted hereunder, and all communications with respect thereto or in the course thereof, including all transcripts, briefs and exhibits, shall be confidential. Unless the parties otherwise agree in writing or except as required by law or as is necessary to enforce this Agreement or any award, the parties, their representatives, and the arbitrator shall not disclose to any third parties (other than to the parties’ respective attorneys, accountants, auditors, financial advisors, and spouses, as applicable, each of whom shall maintain such information in strict confidence, and, in the case of Aon, except as reasonably necessary in the course of its business) any information regarding the arbitration process or proceedings, including any testimony, other evidence and briefs presented and the terms of any award. All written materials and documents produced by a party, and all copies thereof, shall be returned by the other party to the producing party or destroyed (as the producing party shall direct) promptly after the arbitration is concluded, except that legal counsel (both internal and outside, as applicable) for a party may retain copies thereof in legal counsel’s confidential files.

3.Venue and Jurisdiction. Venue for any arbitration proceedings instituted under this Agreement shall be exclusively in Chicago, Illinois (unless the parties otherwise agree), and the parties hereby submit and agree to the exclusive jurisdiction of the State of Illinois for the purposes of any such arbitration. The parties also hereby submit and agree to the exclusive venue and exclusive jurisdiction of the federal and state courts in Chicago, Illinois for the purpose of any claim or action to enter judgment enforcingan arbitration decision or award (whether interim or final) rendered pursuant to Section 2 of this Appendix B-2 above, and for any other claim or action (if any) arising under or relating to this Agreement (whether or not such claim or action is validly asserted in light of Section 2 of this Appendix B-2 above), and the parties hereby agree that any such claim or action (if any) shall be brought exclusively in such federal and state courts in Chicago, Illinois. Nothing in this Section waives or limits in any way a party’s arbitration or other obligations under Section 2 of this Appendix B-2 above or under any other provision of this Agreement.

4.Severability. To the extent that the terms set forth in this Agreement or any word, phrase, clause or sentence is found to be illegal or unenforceable for any reason, such word, phrase, clause or sentence shall be modified or deleted in such manner so as to afford the Company the fullest protection commensurate with making this Agreement, as modified, legal and enforceable under

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applicable laws, and the balance of this Agreement shall not be affected thereby, the balance being construed as severable and independent.

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APPENDIX B-3

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE FOR NON-U.S. PARTICIPANTS
In Connection with the Performance Cycle
January 1, 2021 through December 31, 2023

The following terms and conditions apply for Participants who reside outside the United States or who are otherwise subject to the laws of a country other than the United States.

Acknowledgment of Nature of the Program and the Performance Share Units

By accepting the grant of the Performance Share Units, the Participant acknowledges, understands and agrees that:

(1)the Program is established voluntarily by the Company, it is discretionary in nature, and it may be modified, amended, suspended or terminated by the Company at any time without notice and without compensation;

(2)the grant of the Performance Share Units is exceptional, voluntary and occasional and does not create any contractual or other right to receive any or the same number of Performance Share Units, or benefits in lieu of Performance Share Units, even if such Performance Share Units or a certain number of Performance Share Units have been granted in the past;

(3)all decisions with respect to future grants of Performance Share Units, if any, will be at the sole discretion of the Company;

(4)the Participant’s participation in the Program shall not interfere with the ability of the Employer to terminate the Participant’s employment or service relationship (if any) at any time;

(5)the Participant is voluntarily participating in the Program;

(6)the Performance Share Units and the underlying Ordinary Shares, and the income from and value of same, are not intended to replace any pension rights or compensation;

(7)the Performance Share Units and the underlying Ordinary Shares, and the income from and value of same, are extraordinary items that do not constitute compensation of any kind for services of any kind rendered to the Company or the Employer, and which are outside the scope of the Participant’s employment or service contract, if any;

(8)the Performance Share Units and the underlying Ordinary Shares, and the income from and value of same, are not part of normal or expected compensation for any purposes, including, but not limited to, calculating any severance, resignation, termination, redundancy, dismissal, end of service payments, holiday pay, bonuses, long-service awards, pension or retirement or welfare benefits or similar mandatory payments, and in

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no event should be considered as compensation for, or relating in any way to, past services for the Company or the Employer or any Subsidiary;

(9)the grant of the Performance Share Units and the Participant’s participation in the Program will not be interpreted to form an employment or service contract with the Company or any Subsidiary or Affiliate;

(10)the future value of the underlying Ordinary Shares is unknown, indeterminable and cannot be predicted with certainty;

(11)in the event of termination of the Participant’s services (whether or not later found to be invalid or in breach of employment laws in the jurisdiction where the Participant is employed or the terms of the Participant’s employment agreement, if any), unless otherwise provided in the Program or this Agreement or determined by the Company, the Participant’s right to vest in the Performance Share Units under the Program, if any, will terminate effective as of the date that the Participant is no longer actively providing services; the Company shall have the exclusive discretion to determine when the Participant is no longer actively providing services for purposes of the Participant’s Award of Performance Share Units;

(12)no claim or entitlement to compensation or damages, including pro-rated compensation or damages, shall arise from forfeiture of the Performance Share Units resulting from the Participant’s ceasing to provide services to the Employer or the Company (or any Subsidiary) (regardless of the reason for such termination and whether the termination is later found to be invalid or in breach of employment laws in the jurisdiction where the Participant is employed or the terms of the Participant’s employment agreement, if any) and in consideration of the grant of the Performance Share Units to which the Participant is not otherwise entitled, the Participant irrevocably agrees never to institute any claim against the Company, the Employer or any Subsidiary or Affiliate, waives the Participant’s ability, if any, to bring any such claim and releases the Company, the Employer and any Subsidiary or Affiliate from any such claim; if, notwithstanding the foregoing, any such claim is allowed by a court of competent jurisdiction, then, by accepting the Performance Share Units, the Participant shall be deemed irrevocably to have agreed not to pursue such claim and agrees to execute any and all documents necessary to request dismissal or withdrawal of such claims;

(13)unless otherwise agreed with the Company, the Performance Share Units and the underlying Ordinary Shares, and the income from and value of same, are not granted as consideration for, or in connection with, any service the Participant may provide as a director of a Subsidiary or Affiliate;

(14)the Performance Share Units and the benefits evidenced by this Agreement do not create any entitlement, not otherwise specifically provided for in the Program document or provided by the Company in its discretion, to have the Performance Share Units or any such benefits transferred to, or assumed by, another company nor to be exchanged,

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cashed out or substituted for, in connection with any corporate transaction affecting the Shares; and

(15)neither the Company, the Employer nor any Subsidiary or Affiliate shall be liable for any foreign exchange rate fluctuation between the Participant’s local currency and the United States Dollar that may affect the value of the Performance Share Units or of any amounts due to the Participant pursuant to the vesting/settlement of the Performance Share Units or the subsequent sale of any Ordinary Shares acquired upon vesting/settlement.

Conditions

The Company and its Subsidiary, Aon Corporation, a Delaware corporation with its corporate and business headquarters in Chicago, Illinois, and Aon Corporation’s Subsidiaries and Affiliates (and divisions thereof) (collectively referred to in this Appendix B as the “Company”) are in the business of providing conventional and alternative risk management products and services covering the businesses of insurance brokerage, reinsurance brokerage, benefits consulting, compensation consulting, human resources consulting, human resources and benefits outsourcing management, investigatory and security consulting, managing underwriting and related services, including accounting, actuarial, claims management and handling, and information systems on behalf of commercial and individual clients which are national and international and are not confined to any geographic area (the “Business”). An essential element of the Business is the development and maintenance of personal contacts and relationships with clients. Because of these contacts and relationships, it is common for the Company’s clients to develop identification with the employee who services its Business needs, rather than with the Company itself. The personal identification of clients of the Company with a Company employee creates potential for the employee’s appropriation of the benefits of the relationships developed with clients on behalf of and at the expense of the Company. Since the Company would suffer irreparable harm if the employee left its employment and solicited any business of clients of the Company of the same type or kind as the Business performed by Aon or if the employee left its employ and solicited other employees of the Company, it is reasonable to protect the Company against solicitation activities by the employee for a limited period of time after the employee leaves the Company and for the Company to make the award of Performance Share Units conditional on the Participant not engaging in such solicitation activities.

It is therefore a condition of this Agreement that:

1.    the Participant agrees that the Participant will not for 12 months after the Participant’s Termination Date either directly or indirectly:

1.1    in competition with the Company solicit, canvass or approach or endeavour to solicit, canvass or approach, or handle or accept business of the same type or kind as the Business performed by Aon from, either on the Participant’s own behalf or on behalf of any other person, firm or company, any client or prospective client of the Company with which the Participant had material dealings or for which the Participant was responsible or in relation to which the Participant was in possession of confidential information at any time during the Relevant Period; or

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1.2    solicit or entice away or endeavour to solicit or entice away from the Company, either on the Participant’s own behalf or on behalf of any other person, firm or company, any person who is employed by or is an agent, officer or consultant to the Company with whom the Participant had dealings as a colleague in the Relevant Period and who by reason of their seniority or position is likely to be in possession of confidential information which is likely to be of assistance to any person, firm or company competing with the Company whether or not such person would commit a breach by reason of their leaving the Company;

2.    any unvested Performance Share Units of any Participant will be immediately forfeited if the Company considers that the Participant has at any time in the period of two years after the Participant’s Termination Date (without the prior written consent of the Company) either directly or indirectly:

2.1    in competition with the Company solicited, canvassed or approached or endeavored to solicit, canvass or approach, or handled or accepted business of the same type or kind as the Business performed by Aon from, either on the Participant’s own behalf or on behalf of any other person, firm or company, any client or prospective client of the Company with which the Participant had material dealings or for which the Participant was responsible or in relation to which the Participant was in possession of confidential information at any time during the Relevant Period; or

2.2    solicited or enticed away or endeavoured to solicit or entice away from the Company, either on the Participant’s own behalf or on behalf of any other person, firm or company, any person who is employed by or is an agent, officer or consultant to the Company and with whom the Participant had dealings as a colleague in the Relevant Period and who by reason of their seniority or position is likely to be in possession of confidential information which is likely to be of assistance to any person, firm or company competing with the Company whether or not such person would commit a breach by reason of their leaving the Company.

For the purposes of (1) and (2) above:

(a)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

(b)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

(c)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

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(d)the parties agree that the provisions contained in (1) and (2) above will apply globally unless the parties have specified a reduced territory in the Participant’s employment agreement, in which case the territory specified in the employment agreement will prevail and govern; and

(e)to the extent the parties have set forth an alternate restraint on competition and/or solicitation in the Participant’s employment agreement, the version set forth in the employment agreement will prevail and govern.

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APPENDIX C

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE
In Connection with the Performance Cycle
January 1, 2021 through December 31, 2023

Terms and Conditions

This Appendix C includes special terms and conditions applicable to Participants in the countries below. These terms and conditions are in addition to, or, if so indicated, in place of, the terms and conditions set forth in the Agreement, including Appendices A, B-1, B-2, and B-3.

Notifications

This Appendix C also includes notifications relating to exchange control and other issues of which the Participant should be aware with respect to the Participant’s participation in the Program. The information is based on the exchange control, securities and other laws in effect in the respective countries as of February 2021. Such laws are often complex and change frequently. As a result, the Company strongly recommends that the Participant not rely on the information noted herein as the only source of information relating to the consequences of the Participant’s participation in the Program because the information may be out of date at the time the Participant vests in the Performance Share Units or sells Ordinary Shares the Participant acquires under the Program.

In addition, the information is general in nature and may not apply to the Participant’s particular situation, and the Company is not in a position to assure the Participant of any particular result. Accordingly, the Participant should seek appropriate professional advice as to how the relevant laws in the Participant’s country apply to the Participant’s specific situation.

If the Participant is a citizen or resident of a country other than the one in which the Participant is currently working, transfers employment and/or residency after the Performance Share Units are granted, or is considered a resident of another country for local law purposes, the notifications contained in this Appendix C may not be applicable to the Participant. In addition, the Company shall, in its discretion, determine to what extent the terms and conditions contained herein shall be applicable to the Participant.

Argentina

Terms and Conditions

Appendix B-3. Appendix B-3 is amended to include a new Section as follows:

Nothing in this Agreement shall affect the Company’s right to commence legal proceedings in any appropriate jurisdiction, or concurrently in more than one jurisdiction, or to serve process, pleadings and other legal papers upon the Participant in any manner authorised by the laws of any such jurisdiction for any potential violation of Appendix B-3. In addition, the Participant irrevocably waives, to the fullest extent permitted by applicable law: (i) any objection which it may now or hereafter have to the venue of

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any action, suit or proceeding brought in any court referred to in this Section; and (ii) any claim that any such action, suit or proceeding brought in any such court has been brought in an inconvenient forum. To the extent that the Participant may, in any suit, legal action or proceeding brought in a court of the Republic of Argentina or elsewhere arising out of or in connection with this Agreement, be entitled to the benefit of any provision of law requiring the Company in such suit, legal action or proceeding to post security for the Participant’s costs or to post a bond or to take similar action, as the case may be, the Participant hereby irrevocably waives such benefit, in each case to the fullest extent now or hereafter permitted under the laws of any applicable jurisdiction. The Participant expressly recognises that either the Company or its subsidiary employing the Participant, Aon Risk Services Argentina S.A.; Aon Soluciones S.A.; Asevasa Argentina S.A.; Aon Benfield Argentina S.A.; or Aon Affinity Argentina S.A., as applicable, may bring any such legal proceeding.

Notifications

Securities Law Notice. The Performance Share Units and the Ordinary Shares to be issued pursuant to the Performance Share Units are not publicly offered or listed on any stock exchange in Argentina. As they are offered in a private transaction, the Performance Share Units and Shares are not subject to securities registration under Argentine law.

Tax/Exchange Control Information. The Participant must comply with any and all Argentine currency exchange restrictions, approvals and reporting requirements in connection with the Performance Share Units. For example, the Participant is required to report any equity interests the Participant holds in a foreign company (e.g., Ordinary Shares acquired under the Program) as of December 31 on the Participant’s informative annual tax return. In addition, the Participant also is required to report the Participant’s equity interests for personal assets tax purposes.

Provided the Participant is not required to purchase foreign currency and remit funds out of Argentina to acquire Ordinary Shares under the Program, local exchange control restrictions should not apply. However, exchange control regulations in Argentina are subject to frequent change.

The Participant should consult with the Participant’s personal legal advisor regarding any exchange control obligations that may arise from participation in the Program.

Australia

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Australia) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Appendix B-3. Appendix B-3 is amended by deleting the final section and replacing it with the following:

For the purposes of (1) and (2) above:

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(a)“Company” means Aon plc, a public company incorporated under Irish law, and each of its affiliates and subsidiaries including, without limitation, the following:

1.Aon Benfield Australia Limited an Australian corporation;

2.Aon Hewitt Financial Advice Limited an Australian corporation;

3.Aon Hewitt Limited an Australian corporation;

4.Aon Services Pty Limited an Australian corporation;

5.Aon Superannuation Pty Limited an Australian corporation;

6.Aon Risk Services Australia Limited, an Australian corporation;

7.Aon Hewitt (PNG) Limited a Papua New Guinean corporation;

8.Aon Risk Services (PNG) Limited a Papua New Guinean corporation;

9.Aon Superannuation (PNG) Limited a Papua New Guinean corporation;

10.HIA Insurance Services Pty Limited an Australian corporation;

11.One Underwriting Pty Limited an Australian Corporation;

12.Aon Product Design & Development Australia Pty Ltd, an Australian corporation;

13.Hewitt Associates Pty Ltd, an Australian corporation;

14.Aon Charitable Foundation Pty Ltd, an Australian corporation;

15.Aon Risk and Asset Management Pty Ltd, an Australian corporation; and

16.Affinity Risk Partners (Brokers) Pty Limited.

(b)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

(c)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

(d)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

(e)the parties agree that nothing in the provisions contained in (1) and (2), shall (or be construed so as to) limit any restraints on competition and/or solicitation in the Participant’s employment agreement.

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Notifications

Australia Offer Document. The offer of Performance Share Units is intended to comply with the provisions of the Corporations Act 2001, ASIC Regulatory Guide 49 and ASIC Class Order CO 14/1000. Additional details are set forth in the offer document distributed with this Agreement.

Tax Information. Subdivision 83A-C of the Income Tax Assessment Act, 1997, applies to Performance Share Units granted under the Program, such that the Performance Share Units are intended to be subject to deferred taxation.

Belgium

Terms and Conditions

Appendix B-3. Appendix B-3 is amended to include a new Section as follows:

Nothing in this Agreement shall affect the Company’s right to commence legal proceedings in any appropriate jurisdiction, or concurrently in more than one jurisdiction, or to serve process, pleadings and other legal papers upon the Participant in any manner authorised by the laws of any such jurisdiction, including in Belgium, for any potential violation of Appendix B-3. In addition, the Participant irrevocably waives, to the fullest extent permitted by applicable law: (i) any objection which it may now or hereafter have to the venue of any action, suit or proceeding brought in any court referred to in this Section; and (ii) any claim that any such action, suit or proceeding brought in any such court has been brought in an inconvenient forum. To the extent that the Participant may, in any suit, legal action or proceeding brought in a court of Belgium or elsewhere arising out of or in connection with this Agreement, be entitled to the benefit of any provision of law requiring the Company in such suit, legal action or proceeding to post security for the Participant’s costs or to post a bond or to take similar action, as the case may be, the Participant hereby irrevocably waives such benefit, in each case to the fullest extent now or hereafter permitted under the laws of any applicable jurisdiction.

Notifications

Tax/Exchange Control Reporting. The Participant is required to report any taxable income attributable to the grant of the Performance Share Units on the Participant’s annual tax return. In addition, the Participant is required to report any securities, bank or brokerage accounts opened and maintained outside Belgium on the Participant’s annual income tax return. In a separate report, the Participant must provide the National Bank of Belgium with certain details regarding such foreign securities, bank or brokerage accounts (including the account number, bank name and country in which such account was opened). This report, as well as additional information on how to complete it, can be found on the website of the National Bank of Belgium, www.nbb.be, under the Kredietcentrales / Centrales des crédits caption.

Bermuda

Terms and Conditions

Third Party Rights. The Company is entering into this Agreement for itself and as agent for and trustee of the Employer and all other Subsidiaries and Affiliates and is duly authorised to do so. The parties

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intend that the Employer and each Subsidiary and Affiliate should be able to enforce in its own right the terms of this Agreement which expressly or impliedly confer a benefit on that company subject to and in accordance with applicable statute, law or regulation concerning third party rights.

Appendix B-3. Appendix B-3 of this Agreement is deleted in its entirety and replaced with the following.

Conditions

The Company (in this Appendix B-3 such term to include the Bermuda Company and all Group Companies as defined below) is in the business of providing insurance brokerage, reinsurance brokerage, benefits consulting, compensation consulting, human resources consulting, managing underwriting and related services including accounting, claims management and handling, contract wording, information systems and actuarial services. An essential element of its business is the development and maintenance of personal contacts and relationships with clients. Because of these contacts and relationships, it is common for the Company’s clients to develop identification with the employee who services its insurance needs, rather than with the Company itself. The personal identification of clients of the Company with a Company employee creates potential for the employee’s appropriation of the benefits of the relationships developed with clients on behalf of and at the expense of the Company. Since the Company would suffer irreparable harm if the employee left its employment and solicited the insurance or other related business of clients of the Company or if the employee left its employ and solicited other employees of the Company, it is reasonable to protect the Company against solicitation activities by the employee for a limited period of time after the employee leaves the Company and for the Company to make the award of Performance Share Units conditional on the Participant not engaging in such solicitation activities.

In consideration of the granting of Performance Share Units to the Participant, the Participant agrees to the following reasonable conditions and restrictions:

1.    the Participant agrees that the Participant will not for a period of 12 months after the Termination Date (without the prior written consent of the Bermuda Company) either directly or indirectly and whether alone or in conjunction with or on behalf of any other person, organisation or entity and whether as a principal, shareholder, director, employee, agent, consultant, partner or otherwise:

1.1    be involved in any Capacity with any business concern which is (or intended to be) in competition with any Relevant Product and Services;

1.2    solicit, canvass or approach or cause to be solicited, canvassed or approached, or deal or contract with or accept business from any Relevant Client in relation to the supply or provision of any Relevant Products or Services, or endeavour to do so; or

1.3    solicit, induce, encourage, or entice away or endeavour to solicit, induce, encourage or entice away from the Bermuda Company or any Relevant Group Company any person who is employed by or is an agent, officer, independent contractor or consultant appointed or engaged by the Bermuda Company or a Relevant Group Company (i) in a senior, executive, professional, technical or sales capacity and with whom the Participant had material contact in the course of that person’s employment, appointment or

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engagement during the Relevant Period; or (ii) for whom the Participant had direct or indirect managerial responsibility during the Relevant Period, and in either case whether or not such person would commit any breach of the Participant’s contract of employment or engagement by leaving the service of the Bermuda Company or Relevant Group Company;

2.    any unvested Performance Share Units of any Participant will be immediately forfeited if the Company considers that the Participant has breached the restrictions at 1 above; and

3.    None of the restrictions in clause 1 shall prevent the Participant from:

(i)holding an investment by way of shares or other securities of not more than 5% of the total issued share capital of any company, whether or not it is listed or dealt in on a recognised stock exchange; or

(ii)being engaged or concerned in any business concern, provided that the Participant’s duties or work shall relate solely to services or activities of a kind with which the Participant was not concerned to a material extent in the 12 months before the Termination Date.

4.    the Participant shall be prohibited both during the Participant’s employment (otherwise than in the proper performance of the Participant’s duties and then only to those who need to know such Confidential Information for legitimate business reasons) or thereafter (except with the prior written consent of the Bermuda Company or as required by law) from:

(a)divulging or communicating to any person (including, but not limited to, any representative of the press or broadcasting or other media);

(b)causing or facilitating any unauthorised disclosure or publication through any failure by the Participant to exercise all due care, skill and diligence; or

(c)making use of or encouraging or permitting the use of (other than for the benefit of the Bermuda Company and any Relevant Group Company), any Confidential Information which may have come to the Participant’s knowledge or possession or control during the Participant’s employment. The Participant must also use the Participant’s best endeavours to prevent the publication or disclosure of any such Confidential Information.

This restriction will not apply to:

(i)Confidential Information which the Participant can demonstrate is in the public domain otherwise than through unauthorised disclosure; or

(ii)any disclosure required by the order of a court of competent jurisdiction or as otherwise required by law.

5.    For the purposes of (1) through (4) above:

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(a)The following words and expressions shall have the following meanings:

(i)“Confidential Information” has the meaning given within the Business Confidentiality provisions of the contractual section of the Bermuda employee handbook, as amended from time to time;

(ii)“Capacity” as agent, consultant, director, employee, owner, partner, shareholder or in any other capacity;

(iii)“Group Company” means the Company and its Holding Companies, its Subsidiary Companies and its Affiliated Companies from time to time (“Holding Company”, “Subsidiary Company” and “Affiliated Company” having the meanings set out in section 86 Companies Act 1981);

(iv)“Relevant Client” means any person, firm, company or organisation who or which at any time during the Relevant Period is or was (i) negotiating with or engaged in discussions with the Bermuda Company or Relevant Group Company for the sale or supply of Relevant Products or Services; or (ii) a client or customer of, or in the habit of dealing with, the Bermuda Company or Relevant Group Company for the sale or supply of Relevant Products or Services, and in each case with whom or which the Participant had material contact or dealings or about whom or which the Participant was in possession of Confidential Information during the Relevant Period in the course of the Participant’s employment and/or with whom any Bermuda Company or Relevant Group Company employees, agents, officers, consultants or independent contractors reporting to the Participant had material contact or dealings during the Relevant Period in the course of their employment or engagement;

(v)“Relevant Group Company” any Group Company (other than the Bermuda Company) for which the Participant has performed services or for or in respect of which the Participant has had operational/ management responsibility at any time during the Relevant Period;

(vi)“Relevant Period” means the period of 12 months immediately prior to the Termination Date (not including for this purpose any period during which the Participant was suspended or directed not to carry out the Participant’s duties pursuant to the Participant’s contract of employment;

(vii)“Relevant Products or Services” means products or services which are of the same kind as, or of a materially similar kind to or competitive with, any products or services supplied or provided by the Bermuda Company or Relevant Group Company within the Relevant Period and with which the Participant was materially involved in the course of the Participant’s employment during the Relevant Period and with which sale or supply the Participant was directly or otherwise materially concerned or connected or of which the Participant had personal knowledge in the Relevant Period;

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(viii)“Termination Date” means the date on which the Participant’s employment terminates; and

(ix)“Bermuda Company” means Aon Group (Bermuda) Ltd. a company registered in Bermuda with company number 1193;

(b)the period of 12 months in (1) above shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended, placed on garden leave or directed not to carry out the Participant’s duties; and

(c)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

(d)the parties agree that the provisions contained above will apply in any area or territory in which the Participant worked for the Bermuda Company or Relevant Group Company during the Relevant Period or any area or territory in which the Company or Relevant Group Company supplied or provided Relevant Products or Services during the Relevant Period; and

(e)to the extent the parties have set forth an alternate restraint on competition and/or solicitation in the Participant’s employment agreement, the version set forth in this Agreement will prevail and govern.

(f)Governing Law. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to Appendix B-3 only, and the rights and obligations of the parties hereunder, shall be governed by and construed in accordance with the substantive laws of Bermuda, without regard to the conflict of law principles, rules or statutes of any jurisdiction;

(g)Venue and Jurisdiction. Venue for any legal proceedings instituted related to the rights and obligations contained in this Appendix B-3 shall be the courts of Bermuda and the Participant agrees to submit to the exclusive jurisdiction of the courts of Bermuda for purposes of enforcement of the rights and obligations contained hereunder.

Brazil

Terms and Conditions

Appendix B-3. Appendix B-3 is amended to include a new Section as follows:

Nothing in this Agreement shall affect the Company’s right to commence legal proceedings in any appropriate jurisdiction, or concurrently in more than one jurisdiction, or to serve process, pleadings and other legal papers upon the Participant in any manner authorised by the laws of any such jurisdiction for any potential violation of Appendix B-3. In addition, the Participant irrevocably waives, to the fullest extent permitted by applicable law: (i) any objection which it may now or hereafter have to the venue of any action, suit or proceeding brought in any court referred to in this Section; and (ii) any claim that any

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such action, suit or proceeding brought in any such court has been brought in an inconvenient forum. To the extent that the Participant may, in any suit, legal action or proceeding brought in a court of Brazil or elsewhere arising out of or in connection with this Agreement, be entitled to the benefit of any provision of law requiring the Company in such suit, legal action or proceeding to post security for the Participant’s costs or to post a bond or to take similar action, as the case may be, the Participant hereby irrevocably waives such benefit, in each case to the fullest extent now or hereafter permitted under the laws of any applicable jurisdiction. The Participant expressly recognises that either the Company or its subsidiary employing the Participant, Aon Holdings Corretores de Seguros Ltda.; Aon Benfield Brasil Corretora de Resseguros Ltda.; Aon Affinity do Brasil Serviços e Corretora de Seguros Ltda.; Aon Affinity Administradora de Benefícios Ltda.; Farmaseg Solucoes Assistencia e Servicos Empresariais Ltda; or Adm Administradora de Beneficios Ltda, as applicable, may bring any such legal proceeding.

Labor Law Acknowledgment. This provision supplements the Acknowledgment section of Appendix B-3:

In accepting the Performance Share Units, the Participant acknowledges, understands and agrees that, for all legal purposes, (a) the benefits provided to the Participant under the Program are the result of commercial transactions unrelated to the Participant’s employment, (b) the Participant will be entitled to acquire Ordinary Shares only if the Participant continues to be an eligible Participant, (c) the income derived under the Program, if any, is not part of the Participant’s remuneration from employment and (d) the value of the underlying Ordinary Shares is not fixed and may increase or decrease without compensation to the Participant.

Compliance with the Law. In accepting the grant of the Performance Share Units, the Participant acknowledges the Participant’s agreement to comply with applicable Brazilian laws and to pay any and all applicable Tax-Related Items associated with the Performance Share Units, the sale of the Ordinary Shares acquired under the Program and the receipt of any dividends.

Notifications

Exchange Control Information. If the Participant is a resident or domiciled in Brazil, the Participant will be required to prepare and submit an annual declaration of assets and rights held outside of Brazil to the Central Bank of Brazil if the aggregate value of such assets and rights is greater than US$1,000,000. Assets and rights that must be reported include Ordinary Shares issued pursuant to the vesting/settlement of the Performance Share Units.

Canada

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Canada) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

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Termination of Employment. The following provision supplements Section 1(k) of Appendix A: For purposes of the Performance Share Units, the Participant’s employment or other services will be considered terminated, and the Participant’s right (if any) to earn, seek damages in lieu of, vest in or otherwise benefit from any portion of the Performance Share Units pursuant to the Agreement will be measured by the date that is the earliest of (i) the date the Participant’s employment with the Employer is terminated for any reason and (ii) the date the Participant’s receives written notice of termination from the Employer; in either case, regardless of any period during which notice, pay in lieu of notice or related payments or damages are provided or required to be provided under local law. For greater certainty, the Participant will not earn or be entitled to any pro-rated vesting for that portion of time before the date on which the Participant’s right to vest terminates, nor will the Participant be entitled to any compensation for lost vesting. Notwithstanding the foregoing, if applicable employment standards legislation explicitly requires continued vesting during a statutory notice period, the Participant’s right to vest in the Performance Share Units, if any, will terminate effective upon the expiry of the minimum statutory notice period, but the Participant will not earn or be entitled to pro-rated vesting if the date of settlement of the Performance Share Units falls after the end of the statutory notice period, nor will the Participant be entitled to any compensation for lost vesting.

Appendix B-3. Appendix B-3 is amended by deleting the final Section and replacing it with the following:

For the purposes of (1) and (2) above:

(a)“Company” means Aon plc, a public limited company incorporated under Irish law and each if its affiliates and subsidiaries including, without limitation, Aon Canada Inc. and each of its related and/or affiliated companies throughout Canada.

(b)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

(c)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

(d)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

(e)the parties agree that the provisions contained in (1) and (2) above will apply globally unless the parties have specified a reduced territory in the Participant’s employment agreement, in which case the territory specified in the employment agreement will prevail and govern; and

(f)to the extent the parties have set forth an alternate restraint on competition and/or solicitation in the Participant’s employment agreement, the version set forth in the employment agreement will prevail and govern.

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Form of Payment. Notwithstanding any discretion contained in the Program document, the Performance Share Units are payable in Ordinary Shares only.

The following provisions will apply to the Participants who are residents of Quebec:

Language Consent. The parties acknowledge that it is their express wish that the Agreement, as well as all documents, notices and legal proceedings entered into, given or instituted pursuant hereto or relating directly or indirectly hereto, be drawn up in English.

Les parties reconnaissent avoir exigé la rédaction en anglais de cette convention, ainsi que de tous documents, avis et procédures judiciaires, exécutés, donnés ou intentés en vertu de, ou liés directement ou indirectement à, la présente convention.

Data Privacy. This provision supplements Section 11 of Appendix A of the Agreement:

The Participant hereby authorises the Company and the Company’s representatives to discuss with and obtain all relevant information from all personnel, professional or non-professional, involved with the administration of the Program. The Participant further authorises the Company, the Employer or any other Subsidiary or Affiliate and Fidelity or any other stock plan service provider or designated third party that may be selected by the Company in the future to assist with the Program to disclose and discuss the Program with their advisors. The Participant also authorises the Company, the Employer and any other Subsidiary or Affiliate to record such information and to keep such information in the Participant’s file.

Notifications

Securities Law Notice. The Participant is permitted to sell Ordinary Shares acquired through the Program through the designated broker appointed under the Program, if any, provided the resale of Ordinary Shares acquired under the Program takes place outside of Canada through the facilities of a stock exchange on which the Ordinary Shares are listed. The Ordinary Shares are currently listed on the New York Stock Exchange.

Foreign Asset/Account Reporting Information. Specified foreign property, including Ordinary Shares and other rights to receive Ordinary Shares (e.g., Performance Share Units) of a non-Canadian company held by Canadian residents must generally be reported annually on a Form T1135 (Foreign Income Verification Statement) if the total cost of the individual’s specified foreign property exceeds C$100,000 at any time during the year. Thus, such Performance Share Units must be reported - generally at a nil cost - if the C$100,000 cost threshold is exceeded because other specified foreign property is held by the individual. When Ordinary Shares are acquired, their cost generally is the adjusted cost base (“ACB”) of the Ordinary Shares. The ACB would ordinarily equal the fair market value of the Ordinary Shares at the time of acquisition, but if the Participant owns other shares of the same company, this ACB may have to be averaged with the ACB of the other shares.

Colombia

Terms and Conditions

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Labor Law Acknowledgment. This provision supplements the Acknowledgment section of Appendix B-3:

In accepting the Performance Share Units, the Participant acknowledges, understands and agrees that pursuant to Article 15 of Law 50/1990 (Article 128 of the Colombian Labor Code), the Performance Share Units and any payments the Participant receives pursuant to the Performance Share Units are wholly discretionary and are a benefit of an extraordinary nature that do not exclusively depend on the Participant’s performance. Accordingly, the Performance Share Units and any payments the Participant receives pursuant to the Performance Share Units do not constitute a component of “salary” and will not be considered as made in the nature of a salary payment for any and all legal purposes, including for purposes of calculating any and all labor benefits, such as fringe benefits, vacation pay, termination or other indemnities, payroll taxes, social insurance contributions, or any other outstanding employment-related amounts, subject to the limitations provided in Law 1393/2010.

Notifications

Securities Law Notice. The Ordinary Shares are not and will not be registered in the Colombian registry of publicly traded securities (Registro Nacional de Valores y Emisores) and therefore the Ordinary Shares may not be offered to the public in Colombia. Nothing in this document should be construed as the making of a public offer of securities in Colombia.

Exchange Control Information. Investment in assets located abroad (such as Ordinary Shares acquired under the Program) does not require prior approval. However, all investments must be registered with the Central Bank (Banco de la República) regardless of value. In addition, all payments related to the liquidation of such investments must betransferred through the Colombian foreign exchange market (e.g., local banks), which includes the obligation ofcorrectly completing and filing the appropriate foreign exchange form (declaración de cambio).

The Participant is responsible for complying with any and all Colombian foreign exchange restrictions, approvals, registration and reporting requirements in connection with the Performance Share Units and any Ordinary Shares acquired or funds received under the Program.

The Participant should consult with the Participant’s personal legal and tax advisor regarding any such obligations in connection with the Participant’s participation in the Program.

Czech Republic

Notifications

Foreign Asset/Account Reporting Information. The Czech National Bank (“CNB”) may require Czech residents to fulfill certain notification duties in relation to the acquisition of Ordinary Shares and the opening and maintenance of a foreign account. In addition, Czech residents may need to report the following even in the absence of a request from the CNB: (a) foreign direct investments with a value of CZK 2,500,000 or more in the aggregate and (b) other foreign financial assets with a value meeting or exceeding a prescribed threshold. Because exchange control regulations change frequently and without notice, the Participant should consult the Participant’s personal legal advisor regarding participation in the

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Program to ensure compliance with current regulations. It is the Participant’s responsibility to comply with any applicable Czech exchange control laws.

France

Terms and Conditions

Grant of Performance Share Units. The Performance Share Units granted pursuant to this Agreement are not intended to be “French-qualified” restricted stock units and are not eligible for specific tax and/or social security treatment in France under Sections L. 225-197-1 to L. 225-197-5 and Sections L. 22-10-59 to L. 22-10-60 et seq. of the French Commercial Code, as amended.

Language Consent. By clicking on the “I accept” button or signing and returning this document providing for the terms and conditions of this grant, the Participant confirms having read and understood the documents relating to this grant (the Program and this Agreement) which were provided to the Participant in the English language. The Participant accepts the terms of these documents accordingly.

En cliquant sur le bouton “J’accepte” ou en signant et renvoyant le présent document décrivant les termes et conditions de cette attribution, le Participant confirme avoir lu et compris les documents relatifs à cette attribution (le Programme et ce Contrat) qui ont été communiqués au Participant en langue anglaise. Le Participant en accepte les termes en connaissance de cause.

Notifications

Exchange Control Information. The Participant must declare to the customs and excise authorities any cash or securities the Participant imports or exports without the use of a financial institution when the value of the cash or securities is equal to or exceeds €10,000. In addition, the Participant must declare any bank or stock account opened, held or closed abroad to the French tax authorities on an annual basis.

Germany

Notifications

Exchange Control Information. Cross-border payments in excess of €12,500 must be electronically reported on a monthly basis to the German Federal Bank. If the Participant uses a German bank to transfer a cross-border payment in excess of €12,500 in connection with the sale of Ordinary Shares acquired under the Program, the Participant must complete the appropriate report. The form of report (“Allgemeines Meldeportal Statistik”) can be accessed via Bundesbank’s website (www.bundesbank.de) and is available in both German and English.

Foreign Asset/Account Reporting Information. If the acquisition of Ordinary Shares under the Program leads to a so-called qualified participation at any point during the calendar year, the Participant will need to report the acquisition when the Participant files the Participant’s tax return for the relevant year. A qualified participation is attained if (i) the value of the Ordinary Shares acquired exceeds €150,000 or (ii) in the unlikely event the Participant holds Ordinary Shares exceeding 10% of the Company’s total common stock.    

Hong Kong

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Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Hong Kong) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Form of Payment. Notwithstanding any discretion contained in the Program document, the Performance Share Units are payable in Ordinary Shares only.

Sale of Ordinary Shares. Ordinary Shares received at vesting are accepted as a personal investment. In the event the Performance Share Units vest within six months of the Grant Date, the Participant agrees that the Participant will not dispose of the Ordinary Shares acquired prior to the six month anniversary of the Grant Date.

Notifications

Securities Law Notice.Warning: The contents of this document have not been reviewed by any regulatory authority in Hong Kong. The Participant should exercise caution in relation to the offer. If the Participant is in any doubt about any of the contents of the Agreement, including the Appendices, or the Program, the Participant should obtain independent professional advice. The Performance Share Units and underlying Ordinary Shares issued at vesting do not constitute a public offering of securities under Hong Kong law and are available only to employees of the Company or a Subsidiary. The Agreement, including the Appendices, the Program document and other incidental communication materials have not been prepared in accordance with and are not intended to constitute a “prospectus” for a public offering of securities under the applicable securities legislation in Hong Kong. The Performance Share Units are intended only for the personal use of each eligible Participant of the Company and its Subsidiaries and may not be distributed to any other person.

Occupational Retirement Schemes Ordinance Alert. The Company specifically intends that neither the Performance Share Units nor the Program will be an occupational retirement scheme for purposes of the Occupational Retirement Schemes Ordinance (“ORSO”).

Hungary

No country-specific terms apply.

India

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to seek restraining orders or injunctions against the Participant in the courts of any country (including the Courts

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of India) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Notifications

Exchange Control Information. Indian residents are required to repatriate to India any cash proceeds related to Ordinary Shares within a prescribed period of time (i.e., within 90 days of receipt of proceeds from the sale of Ordinary Shares acquired under the Program, and within 180 days of receipt of any cash dividends received in relation to the Ordinary Shares, or within any other timeframe prescribed under applicable Indian exchange control laws as may be amended from time to time) and convert such proceeds into local currency. Indian residents will receive a foreign inward remittance certificate (“FIRC”) from the bank where they deposit the foreign currency and must maintain the FIRC as evidence of the repatriation of funds in the event the Reserve Bank of India or the Employer requests proof of repatriation.

Foreign Asset/Account Reporting Information. Indian residents are required to declare any foreign bank accounts and any foreign financial assets (including Ordinary Shares held outside India) in their annual tax return.  The Participant is responsible for complying with any applicable reporting obligation and should confer with the Participant’s personal tax advisor in this regard.

Ireland

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Ireland) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Appendix B-3. Appendix B-2 is amended by deleting the final section and replacing it with the following:

For the purposes of (1) through (2) above:

(a)“Company” means Aon plc, a public limited company incorporated under Irish law and each of its affiliates and subsidiaries including, without limitation, each of its related and/or affiliated companies throughout Ireland;

(b)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

(c)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

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(d)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

(e)the parties agree that nothing in the provisions contained in (1) and (2), shall (or be construed so as to) limit any restraints on competition and/or solicitation in the Participant’s employment agreement.

Italy

Terms and Conditions

Program Document Acknowledgment. In accepting the grant of the Performance Share Units, the Participant acknowledges that the Participant has received a copy of the Program document and the Agreement and has reviewed the Program document and the Agreement, including the Appendices, in their entirety and fully understands and accepts all provisions of the Program and the Agreement, including the Appendices.

The Participant further acknowledges that the Participant has read and specifically and expressly approves the following sections of the Agreement (including the Appendices): (a) Governing Law; (b) Venue and Jurisdiction; (c) Imposition of Other Requirements; (d) Acknowledgment of Nature of the Program and the Performance Share Units; (e) Tax Withholding Obligations; (f) Language; and (g) Data Privacy.

Notifications

Foreign Asset/Account Reporting Information. If the Participant is an Italian resident and holds investments or financial assets outside of Italy (e.g., cash, Performance Share Units, Ordinary Shares) during any fiscal year which may generate income taxable in Italy (or if the Participant is the beneficial owner of such an investment or asset even if the Participant does not directly hold the investment or asset), the Participant is required to report such investments or assets on the Participant’s annual tax return for such fiscal year (on UNICO Form, RW Schedule, or on a special form if the Participant is not required to file a tax return).

Japan

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Japan) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Notifications

Foreign Asset/Account Reporting Information. The Participant is required to report details of any assets held outside of Japan as of December 31, including Ordinary Shares, to the extent such assets have a total net fair market value exceeding ¥50,000,000. Such report will be due from the Participant by

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March 15 each year. The Participant is responsible for complying with this reporting obligation and should confer with the Participant’s personal tax advisor in this regard.

Exchange Control Information. If the Participant acquires Ordinary Shares valued at more than ¥100,000,000 in a single transaction, the Participant must file a Securities Acquisition Report with the Ministry of Finance through the Bank of Japan within twenty days after acquisition of the Shares.

Lithuania

Notifications

Foreign Asset/Account Reporting Information. The Participant may be required to file an Annual Asset Returnof the Individual (Family) in Form No. FR0001 with respect to assets held outside of Lithuania (i.e., Shares), aswell as a foreign account report if the Participant opens an account with a foreign financial institution with annualturnover in the account exceeding EUR 15,000. The Participant should consult with the Participant’s personal taxadvisor regarding the Participant’s reporting obligations.

Mexico

Terms and Conditions

No Entitlement or Claims for Compensation. These provisions supplement the Acknowledgment section of Appendix B-3:

Modification. By accepting the Performance Share Units, the Participant understands and agrees that any modification of the Program or the Agreement or its termination shall not constitute a change or impairment of the terms and conditions of employment.

Policy Statement. The award of Performance Share Units is unilateral and discretionary and, therefore, the Company reserves the absolute right to amend it and discontinue it at any time without any liability.

The Company, with registered offices at Metropolitan Building, James Joyce Street, Dublin 1, Ireland, D01 K0Y8, is solely responsible for the administration of the Program and the Participant’s participation in the Program and the acquisition of Shares does not, in any way, establish an employment relationship between the Participant and the Company since the Participant is participating in the Program on a wholly commercial basis and the sole employer is Aon Risk Solutions Agente de Seguros y de Fianzas, S.A. de C.V., or Aon Life Agente de Seguros, S.A. de C.V., or Aon México Business Support, S.A. de C.V., or Aon México Holdings, S. de R.L. de C.V., or Aon Affinity México Agente de Seguros y de Fianzas, S.A. de C.V., or Aon Affinity México, S.A. de C.V., or Hewitt Associates, S.C., or Hewitt Beneficios Agente de Seguros y de Fianzas, S.A. de C.V., or Aon Benfield México Intermediario de Reaseguro, S.A. de C.V., as applicable, nor does it establish any rights between the Participant and the Employer.

Program Document Acknowledgment. By accepting the Performance Share Units, the Participant acknowledges that the Participant has received copies of the Program document, has reviewed the Program document and the Agreement in their entirety and fully understands and accepts all provisions of the Program and the Agreement.

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In addition, by accepting the Agreement, the Participant further acknowledges that the Participant has read and specifically and expressly approved the terms and conditions in the Acknowledgment section of Appendix B-3 in which the following is clearly described and established: (i) participation in the Program does not constitute an acquired right; (ii) the Program and participation in the Program is offered by the Company on a wholly discretionary basis; (iii) participation in the Program is voluntary; and (iv) the Company and any Subsidiary are not responsible for any decrease in the value of the Ordinary Shares underlying the Performance Share Units.

Finally, the Participant hereby declares that the Participant does not reserve any action or right to bring any claim against the Company for any compensation or damages as a result of the Participant’s participation in the Program and therefore grants a full and broad release to the Employer, the Company and any Subsidiary with respect to any claim that may arise under the Program.

Sin derecho a compensación o reclamaciones por compensación. Estas disposiciones complementan la Sección de Reconocimiento del Anexo B-3:

Modificación. Al aceptar las Unidades de Acciones Restringidas, el Participante entiende y acuerda que cualquier modificación al Programa o al Contrato o su terminación no constituirá un cambio o perjuicio a los términos y condiciones de empleo.

Declaración de Política. El Otorgamient que la Compañía está haciendo de conformidad con el Programa es unilateral y discrecional y, por lo tanto, la Compañía se reserva el derecho absoluto de modificar y discontinuar el mismo en cualquier momento, sin responsabilidad alguna.

La Compañía, con oficinas registradas ubicadas en Metropolitan Building, James Joyce Street, Dublin 1, Ireland, D01 K0Y8 es únicamente responsable de la administración del Programa y la participación en el Programa y la adquisición de Acciones no establece, de forma alguna, una relación de trabajo entre el Partícipe y la Compañía, ya que el Partícipe participa en el Programa de una forma totalmente comercial y el único patrón es Aon Risk Solutions Agente de Seguros y de Fianzas, S.A. de C.V., o Aon Life Agente de Seguros, S.A. de C.V., o Aon México Business Support, S.A. de C.V., o Aon México Holdings, S. de R.L. de C.V., o Aon Affinity México Agente de Seguros y de Fianzas, S.A. de C.V., o Aon Affinity México, S.A. de C.V., o Hewitt Associates, S.C., o Hewitt Beneficios Agente de Seguros y de Fianzas, S.A. de C.V., o Aon Benfield México Intermediario de Reaseguro, S.A. de C.V., en caso de ser aplicable, y tampoco establece ningún derecho entre el Partícipe y el Patrón.

Reconocimiento del Documento del Programa. Al aceptar el Otorgamiento de las Unidades de Acciones Restringidas, el Participante reconoce que el Partícipe ha recibido copias del Programa, ha revisado el Programa y el Contrato en su totalidad y entiende y acepta completamente todas las disposiciones contenidas en el Programa y en el Contrato.

Adicionalmente, al aceptar el Contrato, el Participante reconoce que ha leído y específica y expresamente ha aprobado los términos y condiciones de la Sección de Reconocimiento del Anexo B-3, en el que claramente se ha descrito y establecido que: (i) la participación en el Programa no constituye un derecho adquirido; (ii) el Programa y la participación en el Programa es ofrecida por la Compañía de forma enteramente discrecional; (iii) la participación en el Programa es voluntaria; y (iv) la

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Compañía y cualquier empresa afiliada no son responsables por cualquier disminución en el valor de las Acciones Ordinarias subyacentes a las Unidades de Acciones Restringidas.

Finalmente, el Partícipe en este acto declara que el Partícipe no se reserva ninguna acción o derecho para interponer una demanda o reclamación en contra de la Compañía por compensación, daño o perjuicio alguno como resultado de su participación en el Programa y, por lo tanto, otorga el más amplio finiquito al Patrón, la Compañía y cualquier empresa afiliada con respecto a cualquier demanda o reclamación que pudiera surgir en virtud del Programa.

Notifications

Securities Law Information. The Performance Share Units and the Shares offered under the Plan have not been registered with the National Register of Securities maintained by the Mexican National Banking and Securities Commission and cannot be offered or sold publicly in Mexico. In addition, the Plan, the Agreement and any other document relating to the Performance Share Units may not be publicly distributed in Mexico. These materials are addressed to the Participant only because of the Participant’s existing relationship with the Company and its Subsidiaries and these materials should not be reproduced or copied in any form. The offer contained in these materials does not constitute a public offering of securities but rather constitutes a private placement of securities addressed specifically to individuals who are present employees of the companies identified below made in accordance with the provisions of the Mexican Securities Market Law, and any rights under such offering shall not be assigned or transferred.

Netherlands

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of The Netherlands) relating to or in any way connected with the place of residency of the Participant, the place where the work is performed, or related to the breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Appendix B-3. Appendix B-3 is amended by deleting the final Section in its entirety and replacing it with the following:

For the purposes of (1) and (2) above:

(a)“Company” means Aon plc, a public limited company incorporated under Irish law and each if its affiliates and subsidiaries including, without limitation, Aon Groep Nederland bv and each of its related and/or affiliated companies throughout the Netherlands.

(b)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

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(c)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

(d)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

(e)the parties agree that the provisions contained in (1) and (2) above will apply globally unless the parties have specified a reduced territory in the Participant’s employment agreement, in which case the territory specified in the employment agreement will prevail and govern; and

(f)to the extent the parties have set forth an alternate restraint on competition and/or solicitation in the Participant’s employment agreement, the version set forth in the employment agreement will prevail and govern.

New Zealand

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of New Zealand) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement.

Appendix B-3. Appendix B-3 is amended by deleting the final Section in its entirety and replacing it with the following:

For the purposes of (1) and (2) above:

(a)“Company” means Aon Corporation, a Delaware corporation and each if its affiliates and subsidiaries including, without limitation, the following:

(i)Aon New Zealand a New Zealand corporation; and

(ii)Aon (Fiji) Limited a Fiji corporation.

(b)“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the Participant was suspended or directed not to carry out the Participant’s duties for the Company); and

(c)the period of 12 months in (1) and the period of two years in (2) shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties for the Company; and

(d)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) and (2) above; and

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(e)the parties agree that nothing in the provisions contained in (1) and (2), shall (or be construed so as to) limit any restraints on competition and/or solicitation in the Participant’s employment agreement.

Notifications

Securities Law Notice. Warning: This is an offer of Performance Share Units over Ordinary Shares. Ordinary Shares give the Participant a stake in the ownership of the Company. The Participant may receive a return if dividends are paid. Ordinary Shares are quoted on the New York Stock Exchange (“NYSE”). This means the Participant may be able to sell them on the NYSE if there are interested buyers. The Participant may get less than the Participant invested. The price will depend on the demand for the Ordinary Shares.

If the Company runs into financial difficulties and is wound up, the Participant will be paid only after all creditors have been paid. The Participant may lose some or all of the Participant’s investment.

New Zealand law normally requires people who offer financial products to give information to investors before they invest. This information is designed to help investors to make an informed decision. The usual rules do not apply to this offer because it is made under an employee share scheme. As a result, the Participant may not be given all the information usually required. The Participant will also have fewer other legal protections for this investment.

In compliance with applicable New Zealand securities laws, the Participant is entitled to receive, in electronic or other form and free of cost, copies of the Company’s latest annual report, relevant financial statements and the auditor’s report on said financial statements (if any).

The Participant should ask questions, read all documents carefully, and seek independent financial advice before committing him- or herself.

Poland

Notifications

Foreign Asset/Account Reporting Information. Polish residents holding foreign securities (including Ordinary Shares) and/or maintaining accounts abroad must report information to the National Bank of Poland on transactions and balances of the securities and cash deposited into such accounts if the value of such securities and cash (when combined with all other assets possessed abroad) exceeds PLN 7 million. If required, the reports must be filed on a quarterly basis on special forms available on the website of the National Bank of Poland.

Further, any fund transfers into or out of Poland in excess of certain thresholds (currently EUR 15,000, unless the transfer of funds is considered to be connected with the business activity of an entrepreneur, in which case a lower threshold may apply) must be effected through a bank in Poland. Polish residents are required to retain all documents related to any foreign exchange transactions for a period of five years, as measured from the end of the year in which the foreign exchange transactions were made.

Portugal

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Terms and Conditions

Language Consent. The Participant hereby expressly declares that the Participant has full knowledge of the English language and has read, understood and fully accepts and agrees with the terms and conditions established in the Program and the Agreement.

Conhecimento da Lingua. O Participante, pelo presente instrumento, declara expressamente que tem pleno conhecimento da língua inglesa e que leu, compreendeu e livremente aceitou e concordou com os termos e condições estabelecidas no Programa e do Contrato.

Notifications

Foreign Asset/Account Reporting Information. If Ordinary Shares are deposited with a Portuguese financial intermediary, the intermediary will be obligated to communicate the acquisition and sale of Ordinary Shares to the Bank of Portugal for statistical purposes and to the Portuguese Tax Authorities.

If Ordinary Shares are not deposited with a Portuguese financial intermediary, the Participant will be required to perform such reporting to the Bank of Portugal for statistical purposes and to the Portuguese Tax Authorities unless the Participant engages a Portuguese financial intermediary to file the reports on the Participant’s behalf.

Puerto Rico

No country-specific terms apply.

Singapore

Terms and Conditions

Venue and Jurisdiction. The following provision supplements Section 2 of Appendix A:

Nothing in this Section 2 shall (or shall be construed so as to) limit the right of the Company to take proceedings against the Participant in the courts of any country (including the Courts of Singapore) relating to or in any way connected with a breach or threatened breach of any of the conditions in Appendix B-3 to this Agreement to seek the appropriate relief (including, but not limited to, injunctive relief).

Sale of Shares. Shares acquired under the Program may not be sold or otherwise offered for sale in Singapore prior to the six-month anniversary of the Grant Date, unless such sale or offer in Singapore is made pursuant to the exemptions under Part XIII Division (1) Subdivision (4) (other than section 280) of the Securities and Futures Act (Chapter 289, 2006 Ed.) (“SFA”) or pursuant to, and in accordance with the conditions of, any other applicable provision(s) of the SFA.

Notifications

Securities Law Notice. The grant of the Performance Share Units is being made pursuant to the “Qualifying Person” exemption under section 273(1)(f) of the SFA and is not made with a view to the underlying Ordinary Shares being subsequently offered for sale to any other party. The Program

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document has not been nor will it be lodged or registered as a prospectus with the Monetary Authority of Singapore.

Director Notification Requirement. Directors (including alternate, substitute or shadow directors) of a Singapore Subsidiary are subject to certain notification requirements under the Singapore Companies Act. Directors must notify the Singapore Subsidiary in writing of an interest (e.g., Performance Share Units, Ordinary Shares, etc.) in the Company or any related companies within a prescribed period of time from (i) its acquisition or disposal, (ii) any change in a previously disclosed interest (e.g., when the Ordinary Shares are sold), or (iii) becoming a director.

South Africa

Terms and Conditions

Securities Law Information. In compliance with South African securities law, the Participant acknowledges that the Participant has been notified that the documents listed below are available for the Participant’s review at the addresses listed below:

•The Company’s most recent annual and quarterly financial statements: https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0000315293&type=10-&dateb=&owner=exclude&count=40.

•The Company’s most recent prospectus: Access the Participant’s www.netbenefits.com account then select Plan & Grant Documents.

The Participant acknowledges that the Participant may obtain a copy of the above documents, without fee, by contacting aonstockadministration@aon.com.

Tax Notification. This provision supplements Section 12 of Appendix A:

By accepting the Performance Share Units, the Participant agrees to notify the Employer of the amount of any gain realized upon vesting. If the Participant fails to advise the Employer of the gain realized upon vesting, the Participant may be liable for a fine. The Participant will be responsible for paying any difference between the actual tax liability and the amount of tax withheld.

Notifications

Exchange Control Information. The Participant is solely responsible for ensuring compliance with applicable exchange control laws and regulations in South Africa. Because no transfer of funds from South Africa is required in connection with the Performance Share Units, no filing or reporting requirements should apply to the Participant when the Performance Share Units are granted or when Ordinary Shares are issued upon vesting/settlement of the Performance Share Units. However, because the exchange control regulations change frequently and without notice, the Participant should consult the Participant’s legal advisor prior to the acquisition or sale of Ordinary Shares issued pursuant to the Performance Share Units to ensure compliance with current regulations. As noted above, it is the Participant’s responsibility to comply with the South African exchange control laws, and neither the Company nor the Employer will be liable for any fines or penalties resulting from failure to comply with applicable exchange control laws and regulations.

Spain

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Terms and Conditions

Termination of Employment.For purposes of the Performance Share Units, a termination of employment includes a termination that is deemed an “unfair dismissal” or a “constructive dismissal.”

Labor Law Acknowledgment. This provision supplements the Acknowledgment section of Appendix B-3:

In accepting the Performance Share Units, the Participant acknowledges that the Participant consents to participation in the Program and has received a copy of the Program.

The Participant understands and agrees that, as a condition of the grant of the Performance Share Units, except as provided for in the Program document or this Agreement, the Participant’s termination of employment for any reason (including for the reasons listed below) will automatically result in the cancellation and loss of any Performance Share Units that may have been granted to the Participant and that were not fully vested on the date of termination. In particular, the Participant understands and agrees that the Performance Share Units will be canceled without entitlement to the Ordinary Shares or to any amount as indemnification if the Participant terminates employment by reason of, including, but not limited to: resignation, disciplinary dismissal adjudged to be with cause, disciplinary dismissal adjudged or recognised to be without good cause (i.e., subject to a “despido improcedente”), individual or collective layoff on objective grounds, whether adjudged or recognised to be with or without good cause or adjudged or recognised to be without cause, material modification of the terms of employment under Article 41 of the Workers’ Statute, relocation under Article 40 of the Workers’ Statute, Article 50 of the Workers’ Statute, unilateral withdrawal by the Employer, and under Article 10.3 of Royal Decree 1382/1985.

Furthermore, the Participant understands that the Company has unilaterally, gratuitously and in its sole discretion decided to grant Performance Share Units under the Program to individuals who may be employees of the Company or a Subsidiary throughout the world. The decision is a limited decision that is entered into upon the express assumption and condition that any grant will not economically or otherwise bind the Company or a Subsidiary on an ongoing basis, over and above the specific terms of the Program. Consequently, the Participant understands that the Performance Share Units are granted on the assumption and condition that the Performance Share Units and the Ordinary Shares issued upon vesting/settlement of the Performance Share Units shall not become a part of any employment contract (either with the Company or a Subsidiary) and shall not be considered a mandatory benefit, salary for any purposes (including severance compensation) or any other right whatsoever. In addition, the Participant understands that the grant of the Performance Share Units would not be made to the Participant but for the assumptions and conditions referred to above; thus, the Participant acknowledges and freely accepts that should any or all of the assumptions be mistaken or should any of the conditions not be met for any reason, then any grant of Performance Share Units shall be null and void.

Notifications

Securities Law Notice. The Performance Share Units do not qualify as securities under Spanish regulations. No “offer of securities to the public,” as defined under Spanish law, has taken place or will take place in the Spanish territory. The present document has not been nor will it be registered with the

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Comisión Nacional del Mercado de Valores (Spanish Securities Exchange Commission) and does not constitute a public offering prospectus.

Exchange Control Information. To participate in the Program, the Participant agrees to comply with exchange control regulations in Spain. The acquisition of Ordinary Shares under the Program must be declared for statistical purposes to the Dirección General de Comercio e Inversiones (the “DGCI”). Because the Participant will not acquire the Ordinary Shares through the use of a Spanish financial institution, the Participant agrees to make the declaration by filing a D-6 form with the DGCI. Generally, the D-6 form must be filed each January while the Ordinary Shares are owned or to report the sale of Ordinary Shares. In addition, the sale of Ordinary Shares must also be declared on the D-6 form filed with the DGCI in January, unless the sale proceeds exceed the applicable threshold (currently €1,502,530), in which case, the filing is due within one month after the sale.

Further, the Participant is required to electronically declare to the Bank of Spain any foreign accounts (including brokerage accounts held abroad), any foreign instruments (including Ordinary Shares acquired under the Program), and any transactions with non-Spanish residents (including any payments of Ordinary Shares made to the Participant pursuant to the Program) if the balances in such accounts together with the value of such instruments as of December 31, or the volume of transactions with non-Spanish residents during the prior or current year, exceed €1,000,000. Once the €1,000,000 threshold has been surpassed in either respect, the Participant will generally be required to report all foreign accounts, foreign instruments and transactions with non-Spanish residents, even if the relevant threshold has not been crossed for an individual item. Generally, the Participant will only be required to report on an annual basis (by January 20 of each year); however, if the balances in the Participant’s foreign accounts together with the value of the Participant’s foreign instruments or the volume of transactions with non-Spanish residents exceed €100,000,000, more frequent reporting will be required.

Foreign Asset/Account Reporting Information. To the extent that the Participant holds rights or assets (e.g., cash or Ordinary Shares held in a bank or brokerage account) outside of Spain with a value in excess of €50,000 per type of right or asset category as of December 31 each year, the Participant is required to report information on such rights and assets on the Participant’s tax return (Form 720) for such year (or at any time during the year in which the Participant sells or disposes of such right or asset). After such rights or assets are initially reported, the reporting obligation will only apply for subsequent years if the value of any previously-reported rights or assets increases by more than €20,000 (for each type of right or asset category) as of each subsequent December 31, or if the Participant transfers or disposes of any previously-reported rights or assets. The Participant should consult with the Participant’s personal tax and legal advisors to ensure compliance with applicable reporting obligations.

Switzerland

Terms and Conditions

Appendix B-3. Appendix B-3 is amended by deleting the definition of “Relevant Period” in its entirety and replacing it with the following:

“Relevant Period” means the last 12 months of a Participant’s active employment (not including for this purpose any period immediately prior to the termination of the Participant’s employment when the

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Participant was suspended or directed not to carry out the Participant’s duties for the Company); and the Participant undertakes not to engage in any of the activities mentioned under the provisions contained in (1) and (2) of Appendix B-3 within Switzerland; and

Appendix B-3 is further amended to include a new Section (3) to the end thereof as follows:

In addition to the consequences provided in this Appendix B-3, in case of breach of the provisions contained in (1) and (2), the Participant must compensate the Company, any other group entity, including the employing entity, for any damages that the Company, any other group entity, including the employing entity, may have incurred as a result of the breach. Furthermore, the Company and/or any other group entity, including the employing entity, shall have the right to request that the Participant cease and desist from any prohibited activities and to apply to any court of competent jurisdiction, including Swiss courts, for injunctive relief.

Notifications

Securities Law Notice. Neither this document nor any other materials relating to the offer of Performance Share Units (i) constitutes a prospectus according to articles 35 et seq. of the Swiss Federal Act on Financial Services (“FinSA”), (ii) may be publicly distributed or otherwise made publicly available in Switzerland to any person other than an employee of the Company or one of its Subsidiaries or (iii) has been or will be filed with, approved or supervised by any Swiss reviewing body according to article 51 of FinSA or any Swiss regulatory authority, including the Swiss Financial Market Supervisory Authority (“FINMA”).

Turkey

Notifications

Securities Law Notice. The Performance Share Units are made available only to employees of the Company and its Subsidiaries, and the offer of participation in the Program is a private offering. The grant of Performance Share Units and the issuance of Ordinary Shares at vesting take place outside of Turkey.

Financial Intermediary Obligation. Any activity related to investments in foreign securities (e.g., the sale of Ordinary Shares) should be conducted through a bank or financial intermediary institution licensed by the Turkish Capital Markets Board and should be reported to the Turkish Capital Markets Board by the bank or intermediary assisting with the transaction. The Participant is solely responsible for complying with this requirement and should consult with a personal legal advisor for further information regarding any obligations in this respect.

United Arab Emirates

Notifications

Securities Law Notice. The Agreement, the Program, and other incidental communication materials are intended for distribution only to employees of the Company and its Subsidiaries for the purposes of an employee compensation or reward scheme.

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The Emirates Securities and Commodities Authority and the Central Bank have no responsibility for reviewing or verifying any documents in connection with this statement. Neither the Ministry of Economy nor the Dubai Department of Economic Development has approved this statement or taken steps to verify the information set out in it, and has no responsibility for it.

The securities to which this statement relates may be illiquid and/or subject to restrictions on their resale. Prospective acquirers of the securities offered should conduct their own due diligence on the securities.

Participants who do not understand the contents of the Agreement or the Program should consult their own authorised financial advisor.

United Kingdom

Terms and Conditions

Tax Withholding Obligations. The following supplements Section 12 of Appendix A:

Without limitation to Section 12 of Appendix A, the Participant agrees that the Participant is liable for all Tax-Related Items and hereby covenants to pay all such Tax-Related Items as and when requested by the Company or the Employer or by Her Majesty’s Revenue and Customs (“HMRC” ) (or any other tax or other relevant authority). The Participant also agrees to indemnify and keep indemnified the Company and the Employer against any taxes or other amounts that they are required to pay or withhold or have paid or will pay on the Participant’s behalf to HMRC (or any other tax or other relevant authority).

Notwithstanding the foregoing, if the Participant is a director or executive officer of the Company (within the meaning of Section 13(k) of the Exchange Act), the terms of the immediately foregoing provision will not apply. In such case, if the amount of any income tax due is not collected from or paid by the Participant within ninety (90) days of the end of the UK tax year in which an event giving rise to the indemnification described above occurs, the amount of any uncollected income tax may constitute a benefit to the Participant on which additional income tax and National Insurance contributions (“NICs”) may be payable. The Participant understands that the Participant will be responsible for paying and reporting any income tax due on this additional benefit directly to HMRC under the self-assessment regime and for paying the Company or the Employer, as applicable, the amount of any employee NICs due on this additional benefit, which the Company or the Employer, as applicable, may obtain from the Participant at any time thereafter by any of the means set forth in Section 12 of Appendix A.

Third Party Rights. The Company is entering into this Agreement for itself and as agent for and trustee of the Employer and all other Subsidiaries and Affiliates and is duly authorised to do so. The parties intend that the Employer and each Subsidiary and Affiliate should be able to enforce in its own right the terms of this Agreement which expressly or impliedly confer a benefit on that company subject to and in accordance with the provisions of the Contracts (Rights of Third Parties) Act 1999 or other applicable statute, law or regulation concerning third party rights.

Appendix B-3. The Conditions section of Appendix B-3 of this Agreement is deleted in its entirety and replaced with the following.

Conditions

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The Company (in this Appendix B-3 such term to include the UK Company and all Group Companies as defined below) is in the business of providing insurance brokerage, reinsurance brokerage, benefits consulting, compensation consulting, human resources consulting, managing underwriting and related services including accounting, claims management and handling, contract wording, information systems and actuarial services. An essential element of its business is the development and maintenance of personal contacts and relationships with clients. Because of these contacts and relationships, it is common for the Company’s clients to develop identification with the employee who services its insurance needs, rather than with the Company itself. The personal identification of clients of the Company with a Company employee creates potential for the employee’s appropriation of the benefits of the relationships developed with clients on behalf of and at the expense of the Company. Since the Company would suffer irreparable harm if the employee left its employment and solicited the insurance or other related business of clients of the Company or if the employee left its employ and solicited other employees of the Company, it is reasonable to protect the Company against solicitation activities by the employee for a limited period of time after the employee leaves the Company and for the Company to make the award of Performance Share Units conditional on the Participant not engaging in such solicitation activities.

In consideration of the granting of Performance Share Units to the Participant, the Participant agrees to the following conditions:

1.    the Participant agrees that the Participant will not for a period of 12 months after the Termination Date (without the prior written consent of the UK Company) either directly or indirectly and whether alone or in conjunction with or on behalf of any other person, organisation or entity and whether as a principal, shareholder, director, employee, agent, consultant, partner or otherwise:

1.1    so as to compete with the UK Company or any Relevant Group Company solicit, canvass or approach or cause to be solicited, canvassed or approached, or deal or contract with or accept business from any Relevant Client in relation to the supply or provision of any Relevant Products or Services, or endeavour to do so; or

1.2    solicit, induce, encourage, or entice away or endeavour to solicit, induce, encourage, or entice away from the UK Company or any Relevant Group Company any person who is employed by or is an agent, officer, independent contractor or consultant appointed or engaged by the UK Company or a Relevant Group Company (i) in a senior, executive, professional, technical or sales or managerial capacity and with whom the Participant had material contact in the course of that person’s employment, appointment or engagement during the Relevant Period; or (ii) for whom the Participant had direct or indirect managerial responsibility during the Relevant Period, and in either case whether or not such person would commit any breach of the Participant’s contract of employment or engagement by leaving the service of the UK Company or Relevant Group Company;

2.    any unvested Performance Share Units of any Participant will be immediately forfeited if the Company considers that the Participant has breached the restrictions at 1 above;

3.    the Participant shall be prohibited both during the Participant’s employment (otherwise than in the proper performance of the Participant’s duties and then only to those who need to know such

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Confidential Information for legitimate business reasons) or thereafter (except with the prior written consent of the UK Company or as required by law) from:

(a)divulging or communicating to any person (including, but not limited to, any representative of the press or broadcasting or other media);

(b)causing or facilitating any unauthorised disclosure or publication through any failure by the Participant to exercise all due care, skill and diligence; or

(c)making use of or encouraging or permitting the use of (other than for the benefit of the UK Company and any Relevant Group Company),

(d)any Confidential Information which may have come to the Participant’s knowledge or possession or control during the Participant’s employment. The Participant must also use the Participant’s best endeavours to prevent the publication or disclosure of any such Confidential Information.

This restriction will not apply to:

(i)Confidential Information which the Participant can demonstrate is in the public domain otherwise than through unauthorised disclosure; or

(ii)any disclosure required by the order of a court of competent jurisdiction or as otherwise required by law; or

(iii) any protected disclosure made by the Participant within the meaning of Part IV A of the Employment Rights Act 1996 made pursuant to and in accordance with the Public Interest Disclosure Act 1998.

4.    For the purposes of (1) through (3) above:

(a)The following words and expressions shall have the following meanings:

(i)“Confidential Information” has the meaning given within the contract of employment of the Participant, as amended from time to time, or otherwise within the confidentiality provisions of the contractual section of the Company’s policies or procedures, as amended from time to time, including without limitation the Aon Code of Business Conduct;

(ii)“Group Company” means the Company and its Parent Undertakings, its Subsidiary Undertakings and the Subsidiary Undertakings of any of its Parent Undertakings from time to time (“Parent Undertaking” and “Subsidiary Undertaking” having the meanings set out in section 1162 Companies Act 2006);

(iii)“Relevant Client” means any person, firm, company or organisation who or which at any time during the Relevant Period is or was (i) negotiating with or engaged in discussions with the UK Company or Relevant Group Company for the sale or supply of Relevant Products or Services; or (ii) a client or customer of, or in the habit of dealing with, the

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UK Company or Relevant Group Company for the sale or supply of Relevant Products or Services, and in each case with whom or which the Participant had material contact or dealings or about whom or which the Participant was in possession of Confidential Information during the Relevant Period in the course of the Participant’s employment and/or with whom any UK Company or Relevant Group Company employees, agents, officers, consultants or independent contractors reporting to the Participant had material contact or dealings during the Relevant Period in the course of their employment or engagement;

(iv)“Relevant Group Company” any Group Company (other than the UK Company) for which the Participant has performed services or for or in respect of which the Participant has had operational/ management responsibility at any time during the Relevant Period;

(v)“Relevant Period” means the period of 12 months immediately prior to the Termination Date (not including for this purpose any period during which the Participant was suspended or directed not to carry out the Participant’s duties pursuant to the Participant’s contract of employment;

(vi)“Relevant Products or Services” means products or services which are of the same kind as, or of a materially similar kind to or competitive with, any products or services supplied or provided by the UK Company or Relevant Group Company within the Relevant Period and with which the Participant was materially involved in the course of the Participant’s employment during the Relevant Period and with which sale or supply the Participant was directly or otherwise materially concerned or connected or of which the Participant had personal knowledge in the Relevant Period;

(vii)“Termination Date” means the date on which the Participant’s employment terminates; and

(viii)“UK Company” means Aon UK Limited a company registered in the UK with company number 00210725;

(b)the period of 12 months in (1) above shall be reduced by the duration of any period immediately prior to the Participant’s Termination Date when the Participant was suspended or directed not to carry out the Participant’s duties pursuant to the Participant’s contract of employment; and

(c)100% of the Performance Share Units awarded to the Participant have been specifically awarded in consideration of the provisions contained in (1) through (3) above; and

(d)the parties agree that the provisions contained in (1) through (3) above will apply in any area or territory in which the Participant worked for the UK Company or Relevant Group Company during the Relevant Period or any area or territory in which the Company or Relevant Group Company supplied or provided Relevant Products or Services during the Relevant Period; and

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(e)to the extent the parties have set forth an alternate restraint on competition and/or solicitation in the Participant’s employment agreement, the version set forth in this Agreement will prevail and govern.

(f)Governing Law. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to Appendix B-3 only, and the rights and obligations of the parties hereunder, shall be governed by and construed in accordance with the substantive laws of Ireland, without regard to the conflict of law principles, rules or statutes of any jurisdiction;

(g)Venue and Jurisdiction. Venue for any legal proceedings instituted related to the rights and obligations contained in this Appendix B-3 shall be the courts of Ireland and the Participant agrees to submit to the exclusive jurisdiction of the courts of Ireland for purposes of enforcement of the rights and obligations contained hereunder.

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AON PLC

LEADERSHIP PERFORMANCE PROGRAM

As Amended and Restated Effective January 1, 2021

1.Overview

The Leadership Performance Program (the “Program”) of Aon plc (the “Company”) has been adopted by the Organization and Compensation Committee of the Company’s Board of Directors (the “Committee) as a sub-plan of the Aon plc Amended and Restated 2011 Incentive Plan, as it may be amended from time to time (the “Stock Plan”). Capitalized terms not defined herein shall have the meaning assigned under the Stock Plan. The Program and all Awards issued hereunder are subject to the terms and conditions of the Stock Plan; in the event of any inconsistency between the Program and the Stock Plan, the Stock Plan will control to the extent consistent with applicable law.

2.Performance Cycle

The “Performance Cycle” means a three-year period commencing on the first day of the first calendar year of the three-year period, over which performance (as determined by the Committee) will be measured for purposes of the Program. A Performance Cycle may overlap with any other Performance Cycle under the Program.

3.Eligibility

As recommended by the Company’s Chief Executive Officer (the “CEO”) and approved by the Committee, key members of the Company’s senior leadership team are eligible to participate in the Program. The CEO is also eligible to participate in the Program as approved by the Committee.

4.Participation

The Committee will approve in writing by June 30 of the first year of the Performance Cycle (unless the Committee determines otherwise) the specific individuals eligible to participate in the Program (the “Participants”), each Participant’s Award (denominated as described below), the Target Earnings Per Share (as defined below), the Threshold Earnings Per Share (as defined below), and the Payout Scale (as defined below). Participants approved by the Committee shall be eligible to participate in the full Performance Cycle, retroactive to the first day of the Performance Cycle. A change in a Participant’s position or role during the Performance Cycle shall not affect the terms of any outstanding Award held by the Participant, subject to the Participant’s continued employment with the Company.

5.Performance Share Units

Each Participant’s Award shall be denominated in either US dollars or as a target number of performance share units (“Performance Share Units”), each representing a Class A Ordinary Share of the Company (an “Ordinary Share”). If the Award is denominated in US dollars, the target number of Performance Share Units under such Award will be derived by dividing the Award by the Fair Market Value of an Ordinary Share on the date the Award is approved in writing by the Committee (the “Grant Date”).

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6.Rules Applicable to Performance Share Units

(a)To the extent earned, the Performance Share Units will vest as of the date the Committee determines and certifies in writing whether and to what extent the applicable performance criteria have been achieved and the resulting payout (the “Settlement Date”), which shall occur as soon as administratively practicable following the end of the Performance Cycle.

(b)The number of Ordinary Shares into which the Performance Share Units settle upon vesting of such Performance Share Units (i) will be determined based on the Company’s actual cumulative Adjusted Earnings Per Share during the Performance Cycle, as compared to the Target Earnings Per Share, and (ii) will range from 0% to 200% of the target number of Performance Share Units awarded, as set forth in the Payout Scale.

(c)The Performance Share Units will settle into Ordinary Shares during the calendar year immediately following the end of the Performance Cycle.

(d)The Company shall have the right to satisfy all federal, state and local withholding tax requirements with respect to a settled Award by withholding Ordinary Shares equivalent in value to the amount of the required withholding (based on the Fair Market Value of an Ordinary Share on the Settlement Date).

(e)The Performance Share Units are not transferable and may not be sold, assigned, pledged, hypothecated or otherwise encumbered.

(f)Until the Settlement Date, the Participant will not be treated as a shareholder as to those Ordinary Shares relating to the Performance Share Units. No cash payments will be provided for dividend equivalents or other distributions.

(g)Each Award will be evidenced by a Performance Award Certificate (the “Certificate”) issued to the Participant. The Certificate, inclusive of its appendices, will set forth the target number of Performance Share Units granted to the Participant, among other terms and conditions. The Participant must sign and return to the Company the Certificate to indicate that the Participant agrees to be bound by the provisions of the Program, including any restrictive covenants set forth in the Certificate. Failure to return a signed Certificate to the Company will result in forfeiture of the Performance Share Units.

(h)Notwithstanding anything herein to the contrary, if a Participant’s employment with the Company terminates before the last day of the Performance Cycle, the following rules will apply to the vesting and settlement of the Performance Share Units, unless determined otherwise by the Committee:

Termination Event Impact on Performance Share Units

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Retirement (solely for Participants whose principal place of work is outside the EU or UK) Termination by Company without Cause Termination by Participant for Good Reason	The Participant will vest in a fraction (determined based on the number of full calendar quarters completed in the Performance Cycle as of the Participant’s termination date, as compared to the total number of calendar quarters in the Performance Cycle) of the Performance Share Units that would have vested and settled following the end of the Performance Cycle based on actual cumulative Adjusted EPS achieved during the Performance Cycle determined in accordance with the Payout Scale, as follows: To the extent earned, Performance Share Units will be settled in Ordinary Shares in accordance with Section 6(c) above.
Death or Total and Permanent Disability	If the Participant’s death or Total and Permanent Disability occurs in the first or second calendar years of the Performance Cycle, the Participant (or the Participant’s estate) will vest in the target number of Performance Share Units, which will be settled in Ordinary Shares as soon as administratively feasible following such death or Total and Permanent Disability. If the Participant’s death or Total Permanent Disability occurs in the third calendar year of the Performance Cycle, the Participant (or the Participant’s estate) will vest in the target number of Performance Share Units or, if greater, the number of Performance Share Units earned based on actual cumulative Adjusted EPS during the Performance Cycle, determined in accordance with the Payout Scale. Performance Share Units will be settled in Ordinary Shares in accordance with Section 6(c) above.
Voluntary Resignation (other than for Good Reason)	Performance Share Units will be forfeited in their entirety.

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Termination by Company for Cause

Performance Share Units will be forfeited in their entirety.

Certain Terminations Following a Change in Control

Following a Change in Control, the Performance Share Units will be subject to the following rules: (i)If the Participant’s employment is terminated by the Company without Cause or by the Participant for Good Reason after the Change in Control but prior to the end of the Performance Cycle, the Participant’s Performance Share Units will immediately vest at the greater of the target Performance Share Units or the number of units that would have been earned based on the proportion of achievement of the Target Earnings Per Share as of the last full calendar quarter preceding or on the Participant’s termination date. Performance Share Units will be settled in Ordinary Shares upon, or as soon as administratively feasible following, the Participant’s termination of employment. (ii)If the Participant’s employment is terminated by the Company for Cause, by the Participant other than for Good Reason, or by reason of the Participant’s death or Total and Permanent Disability, the terms of the Program shall continue to apply to the Performance Share Units as if the Change in Control had not occurred. (iii)If the Company is not the ultimate parent entity following the Change in Control, then all Performance Share Units will be converted into rights to acquire shares of the ultimate parent entity in accordance with Section 5.2 of the Stock Plan, and performance measures will be based on performance of the ultimate parent company (subject to adjustment in accordance with Section 5.2 of the Stock Plan), and not the Company.

(i)Notwithstanding the foregoing, in the event an individual employment agreement or other binding individual written arrangement between a Participant and the Company provides for more favorable vesting of Performance Share Units upon termination of employment or includes restrictive covenants specifically intended to apply to Awards under the Program, the provisions of such employment agreement or binding written arrangement will control if such provisions are approved by the Committee on or before the Grant Date.

(j)Notwithstanding the foregoing, if the successor to the Company in connection with a Change in Control does not assume and continue this Program substantially in its current form, the Performance Share Units shall become immediately vested at the greater of the target Performance Share Units or the number of units that would have been earned based on the proportion of achievement of the Target Earnings Per Share as of the last full calendar quarter as of or preceding the effective date of the Change in Control. Such Units will be settled in Ordinary Shares upon, or as soon as practicable following, the Change in Control.

(k)In the event that the Company’s Chief Executive Officer determines (or, in the case of the Chief Executive Officer as Participant, the Board determines), in the Chief Executive Officer’s or the

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Board’s sole discretion, as applicable, that forfeiture is appropriate based on the finding that (i) the Participant has materially violated Company policies and procedures, including (but not limited to) performing an act of race, sex, national origin, religion, disability, or age-based discrimination, or sexual harassment or any other material violation of the Aon Code of Business Conduct, or (ii) the Participant is in breach of any non-competition, non-solicitation, and/or confidentiality provisions or other restrictive covenants that apply to the Participant, all unvested Performance Share Units shall be forfeited.

7.Performance Measure for Performance Share Units

The performance measure for the Performance Share Units will be expressed as a target cumulative Adjusted Earnings Per Share for the Performance Cycle, as approved by the Committee by resolution (the “Target Earnings Per Share”).

Following the end of the Performance Cycle, the Committee will determine in its sole discretion the payout, which determination shall be final and binding. Performance Share Units will be subject to complete forfeiture if the Company’s performance for the Performance Cycle does not meet or exceed the minimum cumulative Adjusted Earnings Per Share approved by the Committee (the “Threshold Earnings Per Share”) by resolution, and the payout for performance at or above that level will be calculated using the “Applicable Percentage” as set forth on the payout scale approved by the Committee by resolution (the “Payout Scale”).

8.Adjustments to Performance Measures or Results

The Committee will make appropriate adjustments to actual Adjusted Earnings Per Share to take into account material and/or significant items or events as publicly reported in the Company’s annual Form 10-K or quarterly Form 10-Q, including the following and to the extent consistent with the Stock Plan, as amended: gain/loss on disposition of assets or business; extraordinary legal/regulatory judgments, settlements, fines, penalties, and other related expenses; extraordinary market conditions; effects of natural or man-made disasters (e.g., World Trade Center); hyperinflation (e.g., greater than 15%); foreign exchange impact; changes in applicable laws, regulations or accounting principles; and items that are unusual in nature and/or infrequently occurring. The Committee may not otherwise amend the Payout Scale in a manner that would be adverse to a Participant without the Participant’s consent.

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9.Nominal Value

As required under the Aon Ireland Constitution and the Irish Companies Act, at the time of settlement of Ordinary Shares under this Program, the settlement of Ordinary Shares shall be subject to the Participant’s payment of a nominal value (as determined in the sole discretion of the Company and in accordance with such law, as amended from time to time), and such obligation may be satisfied by the Participant in any manner to be established by the Company in its sole discretion.

10.Restrictive Covenants

Awards under the Program shall be subject to and contingent upon the Participant’s acceptance of and compliance with any restrictive covenants set forth in the applicable Performance Award Certificate.

11.Administration

It is expressly understood by the Participant that the Committee has the discretionary authority to administer, construe, and make all determinations necessary or appropriate to the administration of the Program, all of which will be binding upon the Participant. The Committee may delegate its authority to one or more of its members, or to one or more members of the Company’s senior management team, to offer participation in this Program to eligible individuals    . The Company shall, as necessary, adopt conforming amendments to this Program as are necessary to comply with applicable law.

12.General Provisions

All obligations of the Company under this Program with respect to payout of Awards, and the corresponding rights granted thereunder, shall be binding on any successor to the Company, whether the existence of such successor is the result of a direct or indirect purchase, merger, consolidation or other acquisition of all or substantially all of the business and/or assets of the Company.

This Program, together with the Stock Plan and any applicable Performance Award Certificate, constitutes a legal document which governs all matters involved with its interpretation and administration and supersedes any writing or representation inconsistent with its terms.

13.Reservation and Retention of Company Rights

The selection of any individual for participation in this Program will not give that Participant any right to be retained in the employ of the Company. No Participant will at any time have a right to be selected for participation in a future performance-based incentive program despite having been selected for participation in this Program or a previous program.

14.Code Section 409A

The Company intends that this Program and the Awards granted hereunder to U.S. participants be interpreted and construed to be exempt from, or otherwise comply with, Code Section 409A to the extent applicable thereto. Notwithstanding any provision of the Program to the contrary, the Program shall be interpreted and construed consistent with this intent, provided that the Company shall not be required to assume any increased economic burden in connection therewith. With respect to any payment subject to Code Section 409A that is triggered by a “specified employee’s” “separation from service” under Code

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Section 409A (as such terms are defined under Code Section 409A), such payment shall be delayed until the earlier to occur of the Participant’s death or the date that is six months and one day following the Participant’s termination of employment (the “Delay Period”). Upon the expiration of the Delay Period, all payments delayed pursuant to this section shall be paid to the Participant. For purposes of the Program, the terms “retirement,” “termination of employment,” “terminated,” “termination,” and variations thereof, as used in this Program, shall mean a “separation from service” under Code Section 409A. The time or schedule of any payout of Ordinary Shares pursuant to Performance Share Units may not be accelerated for U.S. participants except as otherwise permitted under Code Section 409A. Although the Committee intends to administer the Program so that it will comply with the applicable requirements of Code Section 409A, neither the Company nor the Committee represents or warrants that the Program will comply with Code Section 409A or any other provision of federal, state, local, or non-United States law. Neither the Company, its Subsidiaries, nor their respective directors, officers, employees or advisers shall be liable to any Participant (or any other individual claiming a benefit through any Participant) for any tax, interest, or penalties any participant may owe as a result of compensation paid under the Program, and the Company and its subsidiaries shall have no obligation to indemnify or otherwise protect the Participant from the obligation to pay any taxes pursuant to Code Section 409A.

15.Definitions

(a)“AdjustedEarnings Per Share” or “AdjustedEPS” means the Company’s adjustedearnings per share from continuing operations as publicly reported each quarter, and on an annual basis, in the Company’s earnings release and Form 10-K.

(b)“Cause” means such term as defined in any written binding individual employment agreement entered into between the Participant and the Company and approved by the Committee prior to the Grant Date, or, in the absence of any such agreement or defined term, means the Participant’s: (1) performance of a deliberate act of dishonesty, fraud, theft, embezzlement or misappropriation involving the Participant’s employment with the Company, or breach of the duty of loyalty to the Company; (2) performance of an act of race, sex, national origin, religion, disability, or age-based discrimination which, after investigation, counsel to the Company reasonably concludes will result in liability being imposed on the Company and/or the Participant; (3) material violation of Company policies and procedures including, but not limited to, the Aon Code of Business Conduct; or (4) performance of a criminal act resulting in a criminal felony charge (or equivalent offense in a non-US jurisdiction) brought against the Participant or a criminal conviction of the Participant (other than a conviction of a minor traffic violation). The existence of “Cause” shall be determined by the Committee in its sole discretion.

(c) “Code Section 409A” means Section 409A of the Internal Revenue Code of 1986, as amended, and all regulatory or other interpretive guidance issued thereunder.

(d)“Fair Market Value” means the per share value of the Ordinary Shares as determined by using the closing price of such shares as reported by the New York Stock Exchange on such date (or, if the New York Stock Exchange was not open for trading or the shares were not traded on that day, the next preceding day that the New York Stock Exchange was open for trading and Ordinary Shares were traded).

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(e)“Good Reason” means such term as defined in any written binding individual employment agreement entered into between the Participant and the Company and approved by the Committee prior to the Grant Date. If there is no such agreement, or such agreement does not define “Good Reason,” the Participant’s voluntary termination of employment shall be treated as a voluntary resignation.

(f)“Retirement” means, solely with respect to a Participant whose principal place of work is outside the European Union or United Kingdom, a voluntary termination of employment upon or after the Participant’s attainment of age 55. For purposes of this definition, the principal place of work for a Participant on secondment shall be considered to be the Participant’s home country. With respect to a Participant whose principal place of work is within the European Union or United Kingdom, the Participant’s voluntary termination of employment at any age shall be treated as a voluntary resignation.

(g)“Total and Permanent Disability” means (1) for US employees, entitlement to long-term disability benefits under the Company’s long-term disability program, as amended from time to time, and (2) for non-US employees, such term as established by applicable Company policy or as required by applicable local law or regulations.

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EX-10.50

PERSONAL AND CONFIDENTIAL

July 16, 2019

Darren Zeidel

[REDACTED]

Re: Employment Letter

Dear Darren,    

Aon Corporation (the “Company”) is pleased to confirm in this Employment Letter (this “Letter”) the terms of your employment as Executive Vice President, General Counsel and Company Secretary of Aon plc. Subject to your acceptance of this Letter, your employment pursuant to this Letter will be deemed to have commenced as of July 12, 2019 (the "Effective Date").

1. General.

At-Will Employment. Your employment with the Company pursuant to this Letter constitutes at-will employment and is not for a specified period. Nothing in this Letter is intended or should be construed as a contract for, or guarantee of, continued employment. This Letter supersedes all prior and contemporaneous agreements, negotiations, correspondence, undertakings and communications of the parties, whether oral or written, respecting your employment, and any and all prior employment agreements and amendments thereto between you and the Company; provided , however, that nothing in this Agreement shall limit or release you from any other obligation regarding confidentiality, intellectual or other property, return of property or post-employment competitive or solicitation activities that you have or may have to the Company or any of its affiliates including, without limitation, as set forth in any equity-based awards to which you are a party.

Responsibilities. You will serve in the position of Executive Vice President, General Counsel and Company Secretary of Aon plc, and will be a Level 1 senior executive of the Company (or comparable level if levels are changed). You will have the authority and responsibility consistent with your position, and also will perform other duties on behalf of the Company and its subsidiaries as may from time to time be authorized or directed by the Chief Executive Officer.

Outside Activities. You may engage in charitable, civic or community activities and may serve as a director of any other business corporation, provided that (a) such activities or service do not interfere with your duties hereunder or violate the terms of any restrictive covenants applicable to you, (b) such activities are consistent with the Aon Code of Business Conduct, and (c) such other business corporation provides you with director and officer insurance coverage which, in the opinion of the Company, is adequate under the circumstances.

2.    Compensation.

Base Salary. During your employment pursuant to this Letter, the Company will pay you a base salary at the rate of $550,000 per year (“Base Salary”) with effect from July 16, 2019, payable semi-monthly in accordance with the Company’s executive payroll policy. Your Base Salary will be reviewed annually on the Company’s regular executive compensation review schedule, and will be subject to adjustment at the discretion of the Organization and Compensation Committee of the Company’s Board of Directors (the “Compensation Committee”), which adjusted amount will be thereafter your “Base Salary” for all purposes hereunder.

Annual Incentive Compensation. You will be eligible to participate in the annual incentive compensation program for the Company’s senior executives in accordance with the provisions of such program, as amended from time to time. Your target annual incentive will be 100% of your Base Salary with effect from July 16, 2019. For the 2019 performance period, your annual incentive shall be based on a proration of the base salary and bonus targets in effect for the respective periods. Your annual incentive will be reviewed annually on the Company’s regular executive compensation review schedule, and will be subject to approval at the discretion of the Compensation Committee. You

acknowledge and agree that any such annual incentive compensation program awards will be subject to payment pursuant to and in accordance with the Aon Incentive Stock Program, payable in a combination of cash and an Aon equity-based award, if applicable.

Long-Term Incentive Compensation. You will be eligible to participate in the long-term incentive compensation programs for the Company’s senior executives in accordance with the provisions of such programs, as

Darren Zeidel

July 16, 2019
Page 2

amended from time to time, pursuant to which you will be eligible to receive, subject to the approval of the Compensation Committee, an annual equity award in an amount that reflects and is consistent with your role and contribution. Beginning in 2020, your target award will be 150% of your Base Salary. A special one-time additional award of $175,000 (for a total 2020 award of $1,000,000) will be recommended in recognition of your service in the Executive Vice President, General Counsel and Company Secretary role during 2019. Your annual long-term incentive will be reviewed annually on the Company’s regular executive compensation review schedule, and will be subject to approval at the discretion of the Compensation Committee.

Employee Benefits. During the course of your employment, you will be entitled to participate in the Company’s employee benefit plans generally available to senior executives of the Company. Nothing in this Letter will require the Company to establish, maintain or continue any of the benefits already in existence or hereafter adopted for employees of the Company and nothing in this Letter will restrict the right of the Company to amend, modify or terminate such programs.

Vacation Time. You will not accrue vacation time, but will be entitled to paid vacation time in accordance with usual Company practices applicable to similarly situated employees.

Expense Reimbursement. In accordance with Company policies and procedures and on prescribed Company forms, the Company will reimburse you for all proper expenses incurred by you in the performance of your duties hereunder.

Severance and Change in Control Protection. You will be eligible to participate in the severance and change in control plan for the Company’s senior executives (Senior Executive Committee Combined Severance and Change in Control Plan) in accordance with the provisions of such plan, as amended from time to time.

Restrictive Covenants. The compensation and benefits described above will be provided to you in consideration of your agreement to execute and comply with the Company’s standard non-competition and non-solicitation agreement for senior executives. By accepting this Letter, you ack knowledge the receipt and sufficiency of such consideration.

If you accept the above-described terms and conditions of employment with the Company, please sign below and return this Letter to the Company.

Sincerely,

/s/ Gregory Case

Gregory Case

Chief Executive Officer

Aon Corporation

ACCEPTED AND AGREED on this 16th day of July 2019:

/s/ Darren Zeidel
Darren Zeidel

-2-

EX-10.51

PERSONAL AND CONFIDENTIAL

October 22, 2019

Lisa Stevens

[REDACTED]

Re: Employment Offer Letter

Dear Lisa,    

Aon Corporation (the “Company”) is pleased to confirm in this Employment Letter (this “Letter”) the terms of your employment as Executive Vice President, Chief People Officer of Aon plc. Subject to your acceptance of this Letter, your employment pursuant to this Letter will be deemed to have commenced as of October 25, 2019 (the "Effective Date").

1. General.

At-Will Employment. Your employment with the Company pursuant to this Letter constitutes at-will employment and is not for a specified period. Nothing in this Letter is intended or should be construed as a contract for, or guarantee of, continued employment. This Letter supersedes all prior and contemporaneous agreements, negotiations, correspondence, undertakings and communications of the parties, whether oral or written, respecting your employment, and any and all prior employment agreements and amendments thereto between you and the Company; provided , however, that nothing in this Agreement shall limit or release you from any other obligation regarding confidentiality, intellectual or other property, return of property or post-employment competitive or solicitation activities that you have or may have to the Company or any of its affiliates including, without limitation, as set forth in any equity-based awards to which you are a party.

Responsibilities. You will serve in the position of Executive Vice President, Chief People Officer of Aon plc., and will be a Level 1 senior executive of the Company (or comparable level if levels are changed). You will have the authority and responsibility consistent with your position and will perform other duties on behalf of the Company and its subsidiaries as may from time to time be authorized or directed by the Chief Executive Officer.

Outside Activities. You may engage in charitable, civic or community activities and may serve as a director of any other business corporation, provided that (a) such activities or service do not interfere with your duties hereunder or violate the terms of any restrictive covenants applicable to you, (b) such activities are consistent with the Aon Code of Business Conduct, and (c) such other business corporation provides you with director and officer insurance coverage which, in the opinion of the Company, is adequate under the circumstances.

2.    Compensation.

Base Salary. During your employment pursuant to this Letter, the Company will pay you a base salary at the rate of $700,000 per year (“Base Salary”) with effect from October 25, 2019, payable semi-monthly in accordance with the Company’s executive payroll policy. Your Base Salary will be reviewed annually on the Company’s regular executive compensation review schedule and will be subject to adjustment at the discretion of the Organization and Compensation Committee of the Company’s Board of Directors (the “Compensation Committee”), which adjusted amount will be thereafter your “Base Salary” for all purposes hereunder.

Annual Incentive Compensation. You will be eligible to participate in the annual incentive compensation program for the Company’s senior executives in accordance with the provisions of such program, as amended from time to time. Your target annual incentive will be 100% of your Base Salary with effect from October 25, 2019. For the 2019 performance period, your annual incentive shall be based on a proration of the base salary and bonus targets in effect for the respective periods. Your annual incentive will be reviewed annually on the Company’s regular executive compensation review schedule and will be subject to approval at the discretion of the Compensation Committee. You acknowledge and agree that any such annual incentive compensation program awards will be subject

to payment pursuant to and in accordance with the Aon Incentive Stock Program, payable in a combination of cash and an Aon equity-based award, if applicable.

Long-Term Incentive Compensation. You will be eligible to participate in the long-term incentive compensation programs for the Company’s senior executives in accordance with the provisions of such programs, as amended from time to time, pursuant to which you will be eligible to receive, subject to the approval of the

Lisa Stevens

October 22, 2019
Page 2

Compensation Committee, an annual equity award in an amount that reflects and is consistent with your role and contribution. Beginning in 2020, your target award will be 150% of your Base Salary. Your annual long-term incentive will be reviewed annually on the Company’s regular executive compensation review schedule and will be subject to approval at the discretion of the Compensation Committee.

Employee Benefits. During the course of your employment, you will be entitled to participate in the Company’s employee benefit plans generally available to senior executives of the Company. Nothing in this Letter will require the Company to establish, maintain or continue any of the benefits already in existence or hereafter adopted for employees of the Company and nothing in this Letter will restrict the right of the Company to amend, modify or terminate such programs.

Vacation Time. You will not accrue vacation time, but will be entitled to paid vacation time in accordance with usual Company practices applicable to similarly situated employees.

Expense Reimbursement. In accordance with Company policies and procedures and on prescribed Company forms, the Company will reimburse you for all proper expenses incurred by you in the performance of your duties hereunder.

Severance and Change in Control Protection. You will be eligible to participate in the severance and change in control plan for the Company’s senior executives (Senior Executive Committee Combined Severance and Change in Control Plan) in accordance with the provisions of such plan, as amended from time to time.

Restrictive Covenants. The compensation and benefits described above will be provided to you in consideration of your agreement to execute and comply with the Company’s standard non-competition and non-solicitation agreement for senior executives. By accepting this Letter, you ack knowledge the receipt and sufficiency of such consideration.

If you accept the above-described terms and conditions of employment with the Company, please sign below and return this Letter to the Company.

Sincerely,

/s/ Gregory Case

Gregory Case

Chief Executive Officer

Aon Corporation

ACCEPTED AND AGREED on this 22nd day of October 2019:

/s/ Lisa Stevens
Lisa Stevens

-2-

EX-10.64

EXECUTION VERSION

AMENDMENT TO THE
AON DEFERRED COMPENSATION PLAN

This Fifth Amendment (“Amendment”) to the Aon Deferred Compensation Plan, as amended and restated effective November 17, 2016 (the “Plan”), is adopted by Aon Corporation, a Delaware corporation (the “Company”) and wholly owned subsidiary of Aon plc, (“Aon”), to be effective as set forth below.

RECITALS

WHEREAS, pursuant to Section 6.05 of the Plan, the Board of Directors of the Company (the “Board”) has the authority to amend the Plan, and, pursuant to Section 1.04 of the Plan, the Organization and Compensation Committee of Aon (the “OCC“) has authority to act for the Board with respect to the Plan; and

WHEREAS, pursuant to resolutions of the OCC dated June 13, 2016, the OCC delegated authority to Aon’s Administrative Committee (the “Committee”) to make certain amendments to the Plan; and

WHEREAS, pursuant to the resolutions of the Committee dated September 14, 2021, the Committee approved, and delegated to Company management authority to execute, an amendment of the Plan to effect a partial Plan termination with respect to certain participants.

NOW THEREFORE, the Plan is hereby amended, effective as of October 1, 2021, by adding the following as a new Supplement B to the Plan:

SUPPLEMENT B

CORPORATE TRANSACTIONS AND PARTIAL PLAN TERMINATIONS

1.Partial Plan Termination – Retiree Health Exchange. The Plan shall be terminated and liquidated, effective October 1, 2021, solely with respect to all Participants who experienced a “change in control event” (within the meaning of Code Section 409A) in connection with the sale of the Aon Retiree Health Exchange. Such termination and liquidation will be administered in accordance with Section 1.409A-3(j)(4)(ix)(B), with the entire vested balance of each such Participant’s account, determined as of February 28, 2022, to be distributed no later than March 15, 2022.

In addition, the Committee is authorized to make any additional adjustments to the plan document language to effect the intent of the foregoing, including but not limited to providing a restatement of the plan document incorporating such changes and all previous amendments.

EXECUTION VERSION

IN WITNESS WHEREOF, the Company has caused the Fifth Amendment to be executed on its behalf by its duly authorized officers, this 16th day of December 2021.

AON CORPORATION                    

By:                            

/s/ Lisa Stevens                

Lisa Stevens

Chief People Officer

EX-10.74

EXECUTION VERSION

SIXTH AMENDMENT

TO THE

AON SUPPLEMENTAL SAVINGS PLAN

(As amended and restated effective January 1, 2017)

This Sixth Amendment to the Aon Supplemental Savings Plan, as amended and restated as of January 1, 2017 (the “Plan”), is adopted by Aon Corporation, a Delaware corporation (the “Company”) and wholly owned subsidiary of Aon plc (“Aon”), to be effective as set forth below.

WHEREAS, pursuant to Section 7.05 of the Plan, the Board, or any person or entity authorized by the Board, has the authority to amend the Plan and, pursuant to Section 1.06 of the Plan, the Board has delegated its obligations, responsibilities, and duties with respect to the Plan to the Organization and Compensation Committee of the Board of Directors of Aon (the “OCC”); and

WHEREAS, pursuant to resolutions of the OCC dated June 13, 2016, the OCC delegated authority to Aon’s Administrative Committee (the “Committee”) to make certain amendments to the Plan; and

WHEREAS, pursuant to the resolutions of the Committee dated September 14, 2021, the Committee approved, and delegated to Company management authority to execute, a Plan amendment to effect a partial Plan termination with respect to certain participants.

NOW, THEREFORE, the Plan is hereby amended as follows, effective October 1, 2021 by adding the following item 2 to Supplement B of the Plan:

“2.     Partial Plan Termination – Retiree Health Exchange. The Plan shall be terminated and liquidated, effective October 1, 2021, solely with respect to all Participants who experienced a ‘change in control event’ (within the meaning of Code Section 409A) in connection with the sale of the Aon Retiree Health Exchange. Such termination and liquidation will be administered in accordance with Section 1.409A-3(j)(4)(ix)(B), with the entire vested balance of each such Participant’s account, determined as of February 15, 2022, to be distributed no later than March 15, 2022.”

In addition, the Committee is authorized to make any additional adjustments to the plan document language to effect the intent of the foregoing, including but not limited to providing a restatement of the plan document incorporating such changes and all previous amendments.

EXECUTION VERSION

IN WITNESS WHEREOF, the Company has caused this Amendment to the Plan to be executed on its behalf by its duly authorized officers, this 16thday of December 2021.

AON CORPORATION

By:

/s/ Lisa Stevens            

Lisa Stevens

Chief People Officer

EX-21.1

			Exhibit 21
Aon plc - Worldwide Subsidiaries as of December 31, 2021
Name	Country	State/Province
Admiseg S.A.	Argentina
Aon Affinity Argentina S.A. (in liquidation)	Argentina
Aon Argentina Corredores de Reaseguros S.A.	Argentina
Aon Risk Services Argentina S.A.	Argentina
Aon Soluciones S.A.	Argentina
Asevasa Argentina S.A.	Argentina
Marinaro Dundas S.A.	Argentina
SN Re S.A.	Argentina
Swire Blanch MSTC II S.A.	Argentina
Swire Blanch MSTC S.A.	Argentina
Affinity Risk Partners (Brokers) Pty Ltd	Australia
Aon Advisory Australia Pty Ltd	Australia
Aon Australia Group Pty Ltd	Australia
Aon Australian Holdco 1 Pty Ltd	Australia
Aon Australian Holdco 2 Pty Ltd	Australia
Aon Australian Holdco 3 Pty Ltd	Australia
Aon Charitable Foundation Pty Ltd	Australia
Aon Consolidated Group Pty Ltd	Australia
Aon Corporation Australia Limited	Australia
Aon Group Pty Ltd	Australia
Aon Hewitt Financial Advice Limited (in liquidation)	Australia
Aon Holdings Australia Pty Ltd	Australia
Aon Product Design & Development Australia Pty Ltd	Australia
Aon Reinsurance Australia Limited	Australia
Aon Risk & Asset Management Pty Ltd	Australia
Aon Risk Services Australia Limited	Australia

Name	Country	State/Province
Aon Services Pty Ltd	Australia
Aon Solutions Australia Limited	Australia
Aon Superannuation Pty Ltd	Australia
Cut-e Australia Pty Ltd	Australia
HIA Insurance Services Pty Ltd	Australia
Hogg Robinson Financial Services Limited	Australia
One Underwriting Pty Ltd	Australia
Aon Austria GmbH	Austria
Aon Holdings Austria GmbH	Austria
Aon Jauch & Hübener Gesellschaft m.b.H.	Austria
Insurance Company of the Bahamas Limited	Bahamas
J.S. Johnson & Company Limited	Bahamas
Aon Bahrain W.L.L.	Bahrain
Aon Insurance Managers (Barbados) Ltd.	Barbados
Agenion N.V./S.A.	Belgium
Aon Belgium B.V.	Belgium
Crion N.V.	Belgium
Probabilitas N.V./S.A.	Belgium
Aon (Bermuda) Ltd.	Bermuda
Aon Bermuda QI Holdings Ltd.	Bermuda
Aon Finance Bermuda 1 Ltd.	Bermuda
Aon Group (Bermuda) Ltd.	Bermuda
Aon Insurance Managers (Bermuda) Ltd.	Bermuda
Aon Underwriting Managers (Bermuda) Ltd.	Bermuda
Benfield Investment Holdings Limited	Bermuda
Benfield Juniperus Holdings Limited	Bermuda
International Risk Management Group Ltd.	Bermuda
Marilla Capital Limited	Bermuda

Name	Country	State/Province
Marilla Investment Management Limited	Bermuda
Marilla Reinsurance Holdings Limited	Bermuda
Marilla Reinsurance Limited	Bermuda
White Rock Insurance (Americas) Ltd.	Bermuda
White Rock Insurance (SAC) Ltd.	Bermuda
White Rock Services (Bermuda) Ltd.	Bermuda
Aon Bermuda Holding Company Limited	Bermuda / Singapore
Aon Bolivia S.A. Corredores de Seguros (in liquidation)	Bolivia
Aon Consulting Bolivia S.R.L. (in liquidation)	Bolivia
Aon Re Bolivia S.A. Corredores de Reaseguros (in liquidation)	Bolivia
ADM Administradora de Benefícios Ltda.	Brazil
Aon Affinity do Brasil Servicos e Corretora de Seguros Ltda.	Brazil
Aon Brasil Corretora de Resseguros Ltda.	Brazil
Aon Holdings Corretores de Seguros Ltda.	Brazil
Associação Instituto Aon	Brazil
Blist – Soluções, Assistência e Serviços Empresariais Ltda.	Brazil
7193599 Canada Inc.	Canada
Aon Canada Holdings N.S. ULC	Canada
Aon Canada Inc.	Canada
Aon Direct Group Inc.	Canada
Aon Finance Canada 1 Corp.	Canada
Aon Finance Canada 2 Corp.	Canada
Aon Finance International N.S. ULC	Canada
Aon Finance N.S. 1, ULC	Canada
Aon Finance N.S. 5, ULC	Canada
Aon Finance N.S. 9, ULC	Canada
Aon Hewitt Inc.	Canada
Aon Investments Canada Inc.	Canada

Name	Country	State/Province
Aon Parizeau Inc.	Canada
Aon Reed Stenhouse Inc.	Canada
Aon Reinsurance Canada ULC	Canada
Aon Risk Services Canada Inc.	Canada
Aon Securities Investment Management Inc.	Canada
Aon Solutions 3 Limited	Canada
Coles Aon Partnership	Canada
Cytelligence Inc.	Canada
Groupe-conseil Aon Inc.	Canada
Hewitt Associates (a partnership)	Canada
Hewitt Associates Corp.	Canada
IAO Actuarial Consulting Services Canada Inc.	Canada
J. Allan Brown Consultants, Inc.	Canada
K & K Insurance Brokers, Inc. Canada	Canada
Linx Underwriting Solutions Inc.	Canada
Minet Inc.	Canada
Townsend (Global Real Estate) GP Ontario Inc.	Canada
USLP Underwriting Solutions LP	Canada
Aon Insurance Managers (Cayman) Ltd.	Cayman Islands
Aon IP Advantage Off-shore Feeder Fund LP	Cayman Islands
Aon Risk Solutions (Cayman) Ltd.	Cayman Islands
Aon Chile Corredores de Reaseguros Ltda.	Chile
Aon Risk Services (Chile) Corredores de Seguros Limitada	Chile
Aon Risk Services Holdings (Chile) Ltda.	Chile
Inversiones Benfield Chile Ltda.	Chile
Aon Corporation Bejing Representative Office	China
Aon Enterprise Solutions (Shanghai) Co., Ltd.	China
Aon-COFCO Insurance Brokers Co., Ltd.	China

Name	Country	State/Province
Aon Affinity Colombia Ltda. Agencia de Seguros en Liquidación	Colombia
Aon Reinsurance Colombia Limitada Corredores de Reaseguros	Colombia
Aon Risk Services Colombia S.A. Corredores de Seguros	Colombia
Salud, Riesgos y Recursos Humanos Consultores Ltda.	Colombia
Tecsefin, S.A. en Liquidación	Colombia
Aon Cyprus Insurance Broker Company Limited	Cyprus
Aon Solutions Cyprus Limited	Cyprus
Aon Central and Eastern Europe a.s.	Czech Republic
Crystal Reinsurance s.r.o.	Czech Republic
ADIS A/S	Denmark
Aon Assessment Denmark A/S	Denmark
Aon Denmark A/S	Denmark
Aon Consulting Ecuador S.A.	Ecuador
Aon Risk Services Ecuador S.A. Agencia Asesora Productora de Seguros	Ecuador
UADBB Aon Baltic (Estonia Branch)	Estonia
Aon (Fiji) Pte Limited	Fiji
ADIS A/S - Finland branch	Finland
Aon Assessment (Finland) Oy	Finland
Aon Finland Oy	Finland
Aon France	France
Aon Holdings France SNC	France
Aon Services S.à.r.l.	France
Aon Assessment GmbH	Germany
Aon Beteiligungsmanagement Deutschland GmbH & Co. KG	Germany
Aon Deutschland Beteiligungs GmbH	Germany
Aon Holding Deutschland GmbH	Germany
Aon Pensions Insurance Broker GmbH	Germany
Aon Risiko- und Unternehmensberatungs GmbH	Germany

Name	Country	State/Province
Aon Solutions Germany GmbH	Germany
Aon Trust Germany GmbH	Germany
Aon Versicherungsberatungs GmbH	Germany
Aon Versicherungsmakler Deutschland GmbH	Germany
Hamburger Gesellschaft zur Forderung des Versicherungswesens mbH	Germany
Motor Service Pensions GmbH	Germany
One Underwriting Agency GmbH	Germany
PRORÜCK Rückversicherungs-Aktiengesellschaft	Germany
SG IFFOXX Assekuranzmaklergesellschaft mbH	Germany
TRIUM GmbH Insurance Broker	Germany
UNIT Versicherungsmakler GmbH	Germany
UnitedPensions Deutschland AG	Germany
Wannet Sports Insurance GmbH	Germany
Aon Insurance Managers Gibraltar Limited	Gibraltar
White Rock Insurance (Gibraltar) PCC Limited	Gibraltar
Aon Greece S.A.	Greece
Aon Solutions Greece S.A.	Greece
Agostini Insurance Brokers Grenada Limited	Grenada
Aon Insurance Managers (Guernsey) Limited	Guernsey
Aon Insurance Managers (Holdings) Limited	Guernsey
Aon PMI International Limited	Guernsey
Aon Services (Guernsey) Limited	Guernsey
Lake Erie Real Estate General Partner Limited	Guernsey
Lincolnshire Insurance Company PCC Limited	Guernsey
Lombard Trustee Company Limited	Guernsey
Townsend Lake Constance GP Limited	Guernsey
White Rock Insurance (Guernsey) ICC Limited	Guernsey
White Rock Insurance Company PCC Limited	Guernsey

Name	Country	State/Province
Aon (CR) Insurance Agencies Company Limited	Hong Kong
Aon Commercial Insurance Agencies Hong Kong Limited	Hong Kong
Aon Holdings Hong Kong Limited	Hong Kong
Aon Hong Kong Limited	Hong Kong
Aon Insurance Agencies (HK) Limited	Hong Kong
Aon Insurance Management Agencies (HK) Limited	Hong Kong
Aon Insurance Underwriting Agencies Hong Kong Limited	Hong Kong
Aon Product Risk Services Hong Kong Limited	Hong Kong
Aon Reinsurance China Limited	Hong Kong
Aon Securities (Hong Kong) Limited	Hong Kong
Aon Services Hong Kong Limited	Hong Kong
Aon Solutions Hong Kong Limited	Hong Kong
Contingency Insurance Brokers Limited	Hong Kong
Cut-e Assessment (Hong Kong) Limited	Hong Kong
E.W. Blanch Limited	Hong Kong
Essar Insurance Services Limited	Hong Kong
Stroz Friedberg (Asia) Limited	Hong Kong
Townsend Group Asia Limited	Hong Kong
Aon Hungary Insurance Brokers Risk and Human Consulting LLC	Hungary
Aon Consulting Private Limited	India
Aon India Insurance Brokers Private Limited	India
PT Aon Hewitt Indonesia (in liquidation)	Indonesia
PT Aon Indonesia	Indonesia
PT Aon Reinsurance Brokers Indonesia	Indonesia
Aon Bahrain W.L.L. (Iraq Branch)	Iraq
Aeropeople Limited (in liquidation)	Ireland
Aon Assessment (Ireland) Limited	Ireland
Aon Assessment Solutions Europe Limited	Ireland

Name	Country	State/Province
Aon Broking Technology Limited	Ireland
Aon Commercial Services and Operations Ireland Limited	Ireland
Aon Commercial Services Ireland Limited	Ireland
Aon Hewitt Management Company Limited (in liquidation)	Ireland
Aon Insurance Managers (Dublin) Limited	Ireland
Aon Insurance Managers (Shannon) Limited	Ireland
Aon Investment Holdings Ireland Limited	Ireland
Aon Ireland Limited	Ireland
Aon plc	Ireland
Aon Randolph Ireland 2 Limited	Ireland
Aon Randolph Ireland 3 Limited	Ireland
Aon REEM Company Limited	Ireland
Aon Solutions Ireland Limited	Ireland
Aon Solutions Limited (Ireland branch)	Ireland
Aon Treasury Ireland Limited	Ireland
Bacon & Woodrow Partnerships (Ireland) Limited (in liquidation)	Ireland
Becketts (Trustees) Limited	Ireland
Benton Finance Ireland Limited (in liquidation)	Ireland
Cut-e Assessment Global Holdings Limited	Ireland
Driftbrook Unlimited Company	Ireland
Private Clients Trustees Limited	Ireland
Randolph Finance Unlimited Company	Ireland
The Aon Ireland MasterTrustee Limited	Ireland
Aon (Isle of Man) Limited	Isle of Man
Aon Corporate Services (Isle of Man) Limited	Isle of Man
Aon Holdings (Isle of Man) Limited	Isle of Man
Aon Insurance Managers (Isle of Man) Limited	Isle of Man
White Rock Insurance PCC (Isle of Man) Limited	Isle of Man

Name	Country	State/Province
Aon Holdings Israel Ltd.	Israel
Aon Israel Insurance Brokerage Ltd.	Israel
Aon Reinsurance Israel Ltd.	Israel
Delek Motors Insurance Agency (2003) Ltd.	Israel
I. Beck Insurance Agency (1994) Ltd.	Israel
National Insurance Office Ltd.	Israel
Ronnie Elementary Insurance Agency Ltd.	Israel
Aon Advisory and Solutions S.r.l.	Italy
Aon Assessment Solutions Europe Limited (Italy branch)	Italy
Aon Italia S.r.l.	Italy
Aon Reinsurance Italia S.p.A.	Italy
Aon S.p.A. Insurance & Reinsurance Brokers	Italy
Coverall S.r.l. Insurance and Reinsurance Underwriting Agency	Italy
Global Safe Insurance Broker S.r.l.	Italy
One Underwriting S.r.l.	Italy
Welfare S.A.	Italy
Aon Group Japan Ltd.	Japan
Aon Holdings Japan Ltd.	Japan
Aon Japan Ltd.	Japan
Aon Solutions Japan Ltd.	Japan
PayPay Insurance Service Corporation	Japan
Townsend Re Global GP Limited	Jersey
Aon Consulting Kazakhstan LLP	Kazakhstan
Insurance Broker Aon Kazakhstan LLP	Kazakhstan
Aon Hewitt Consulting Korea Inc.	Korea
Aon Korea Inc.	Korea
UADBB Aon Baltic (Latvia Branch)	Latvia
Aon Insurance Managers (Liechtenstein) AG	Liechtenstein

Name	Country	State/Province
One Underwriting UAB	Lithuania
UADBB Aon Baltic	Lithuania
Aon Belgium B.V. (Luxembourg Branch)	Luxembourg
Aon Global Operations Luxembourg S.à r.l.	Luxembourg
Aon Global Operations SE	Luxembourg
Aon Global Risk Consulting Luxembourg S.à r.l.	Luxembourg
Aon Holdings Luxembourg S.à r.l.	Luxembourg
Aon Insurance Managers (Luxembourg) S.A.	Luxembourg
Aon Neudorf Finance S.à r.l.	Luxembourg
Aon Randolph Luxembourg S.à r.l.	Luxembourg
Aon Re Canada Holdings S.à r.l.	Luxembourg
TG Voltesso GP S.à r.l.	Luxembourg
TTG Cayuga Bavaria Intermediate 2 S.à r.l. (in liquidation)	Luxembourg
Aon Hong Kong Limited (Macau Branch)	Macau
Aon Insurance Brokers (Malaysia) Sdn. Bhd.	Malaysia
Aon Malaysia Sdn. Bhd.	Malaysia
Aon Reinsurance Malaysia Limited	Malaysia
Aon Insurance Managers (Malta) PCC Limited	Malta
Aon Malta Affinity Services Limited	Malta
Aon Services (Malta) Limited	Malta
White Rock Insurance (Europe) PCC Limited	Malta
White Rock Insurance (Netherlands) PCC Limited	Malta
Aon Mauritius Holdings	Mauritius
Aon Solutions Ltd.	Mauritius
Aon Affinity Mexico Agente de Seguros y de Fianzas, S.A. de C.V.	Mexico
Aon Affinity Mexico, S.A. de C.V.	Mexico
Aon Life, Agente de Seguros, S.A. de C.V.	Mexico
Aon Mexico Business Support, SA de CV	Mexico

Name	Country	State/Province
Aon Mexico Holdings, S. de R.L. de C.V.	Mexico
Aon México Intermediario de Reaseguro, S.A. de C.V.	Mexico
Aon Risk Solutions Agente de Seguros y de Fianzas, S.A. de C.V.	Mexico
Asevasa Mexico, S.A. de C.V.	Mexico
Hewitt Associates, S.C.	Mexico
Hewitt Beneficios Agente de Seguros y de Fianzas, S.A. de C.V.	Mexico
Aon Acore S.a.r.l.	Morocco
Casablanca Intermediation Company S.a.r.l.	Morocco
Alexander & Alexander Holding B.V.	Netherlands
Aon 3 B.V.	Netherlands
Aon Americas Holdings B.V.	Netherlands
Aon APAC Holdings B.V.	Netherlands
Aon CANZ Holdings B.V.	Netherlands
Aon Cash Management B.V.	Netherlands
Aon Global Risk Consulting B.V.	Netherlands
Aon Groep Nederland B.V.	Netherlands
Aon Group Holdings International 1 B.V.	Netherlands
Aon Group Holdings International 2 B.V.	Netherlands
Aon Group International N.V.	Netherlands
Aon Holdings B.V.	Netherlands
Aon Holdings International B.V.	Netherlands
Aon Holdings Mid Europe B.V.	Netherlands
Aon Investments Netherlands B.V.	Netherlands
Aon International B.V.	Netherlands
Aon LATAM Holdings N.V.	Netherlands
Aon Meeùs Assurantiën B.V.	Netherlands
Aon Nederland C.V.	Netherlands
Aon Netherlands Operations B.V.	Netherlands

Name	Country	State/Province
Aon Real Estate B.V.	Netherlands
Aon Risk Services EMEA B.V.	Netherlands
Aon Trust Services B.V.	Netherlands
Bekouw Mendes C.V.	Netherlands
Celinvest Amsterdam B.V.	Netherlands
One Underwriting B.V.	Netherlands
Aon Holdings New Zealand	New Zealand
Aon New Zealand	New Zealand
Aon New Zealand Group	New Zealand
Aon Product Design and Development New Zealand Limited	New Zealand
Aon Reinsurance New Zealand Limited	New Zealand
Aon Saver Limited	New Zealand
Superannuation Management Nominees Limited	New Zealand
Aon Assessment (Norway) AS	Norway
Aon Norway AS	Norway
Cut-e Nordic AS	Norway
Aon Majan LLC	Oman
Aon Benfield Panama S.A. (in liquidation)	Panama
Aon Broking Services S.A. (in liquidation)	Panama
Aon Risk Services (PNG) Limited	Papua New Guinea
Aon Solutions (PNG) Limited	Papua New Guinea
Aon Superannuation (PNG) Limited	Papua New Guinea
Aon Peru Corredores de Reaseguros S.A.	Peru
Aon Peru Corredores de Seguros S.A.	Peru
Aon Soluciones S.A.C.	Peru
Aon Insurance and Reinsurance Brokers Philippines Inc.	Philippines
Aon Insurance Managers (Singapore) Pte Ltd (Pohnpei branch)	Pohnpei (Micronesia)
Aon Polska Services Sp. z o.o.	Poland

Name	Country	State/Province
Aon Polska Sp. z o.o.	Poland
Aon Sp. z o.o.	Poland
Aon Portugal - Consultores, Unipessoal, Lda.	Portugal
Aon Portugal, S.A.	Portugal
Aon Reinsurance S.A.	Portugal
Aon Reinsurance Puerto Rico, Inc.	USA	Puerto Rico
Aon Risk Solutions of Puerto Rico, Inc.	USA	Puerto Rico
Hewitt Insurance, Inc.	USA	Puerto Rico
Aon Qatar LLC	Qatar
Aon Consulting Romania SRL	Romania
Aon Romania Broker de Asigurare - Reasigurare SRL	Romania
Aon Rus Insurance Brokers LLC	Russia
Aon Rus LLC	Russia
Agostini Insurance Brokers (St. Lucia) Limited	Saint Lucia
Aon Hewitt Saudi Arabia LLC	Saudi Arabia
Aon Reinsurance Solutions Saudi Arabia LLC	Saudi Arabia
Aon Saudi Arabia LLC	Saudi Arabia
Alexander & Alexander (Asia) Holdings Pte Ltd	Singapore
Aon Global Operations SE (Singapore Branch)	Singapore
Aon Insurance Agencies Pte Ltd	Singapore
Aon Insurance Managers (Singapore) Pte Ltd	Singapore
Aon Randolph Singapore 2 Pte Ltd	Singapore
Aon Randolph Singapore 3 Pte Ltd	Singapore
Aon Randolph Singapore Pte (in liquidation)	Singapore
Aon Reinsurance Solutions Asia Pte. Ltd.	Singapore
Aon Singapore (Broking Centre) Pte. Ltd.	Singapore
Aon Singapore Center for Innovation, Strategy and Management Pte Ltd	Singapore
Aon Solutions Singapore Pte. Ltd.	Singapore

Name	Country	State/Province
Stenhouse (South East Asia) Private Limited	Singapore
Aon Bratislava s.r.o.	Slovak Republic
Aon Central and Eastern Europe A.S. (Slovakia branch)	Slovak Republic
Aon Consulting South Africa (Pty) Ltd	South Africa
Aon Holdings Sub-Sahara Africa (Pty) Ltd	South Africa
Aon Limpopo (Pty) Ltd	South Africa
Aon Re Africa (Pty) Ltd	South Africa
Aon South Africa (Pty) Ltd	South Africa
Mafube Risk and Insurance Consultants (Pty) Ltd (in process of deregistration)	South Africa
TM Insurance Brokers (Pty) Ltd (in process of deregistration)	South Africa
Aon Consulting Services SA	Spain
Aon Delta Spain S.L.	Spain
Aon Iberia Correduria de Seguros y Reaseguros, S.A.U.	Spain
Aon Marketing Directo, S.A.U.	Spain
Aon Reinsurance Iberia Correduria de Reaseguros, S.A.U.	Spain
Aon Southern Europe y Cia, S.L.	Spain
CoverWallet Innovations, S.L.U.	Spain
Fundación Aon España	Spain
Grupo Innovac Sociedad Correduría de Seguros, S.A.	Spain
Inspiring Benefits, S.L.	Spain
One Underwriting Agencia de Suscripsión, S.L.U.	Spain
Zalba Caldu Correduría de Seguros S.A.	Spain
Aon Assessment (Sweden) AB	Sweden
Aon Global Risk Consulting AB	Sweden
Aon Solutions Sweden AB	Sweden
Aon Sweden AB	Sweden
Aon Insurance Managers (Switzerland) AG	Switzerland
Aon Reinsurance Italia S.p.A., Milano, Succursale di Maroggia (Switzerland Branch)	Switzerland

Name	Country	State/Province
Switzerland Aon Schweiz AG	Switzerland
Assimedia SA	Switzerland
Aon Management Consulting Taiwan Ltd.	Taiwan
Aon Taiwan Ltd.	Taiwan
Aon (Thailand) Limited	Thailand
Aon Consulting (Thailand) Limited	Thailand
Aon Group (Thailand) Limited	Thailand
Aon Re (Thailand) Limited	Thailand
Aon Risk Services (Thailand) Limited	Thailand
Aon Solutions (Thailand) Limited	Thailand
A.B. Insurances Limited	Trinidad and Tobago
Agostini Insurance Brokers Limited	Trinidad and Tobago
AIB Services Limited	Trinidad and Tobago
Aon Energy Caribbean Limited	Trinidad and Tobago
Cardea Health Solutions Limited	Trinidad and Tobago
Aon Sigorta ve Reasurans Brokerligi ve A.S.	Turkey
Aon Solutions Turkey Danismanlik A.S.	Turkey
J.S. Johnson & Company (Turks & Caicos) Limited	Turks & Caicos
Aon Finland Oy (Rep. office) (Ukraine Branch)	Ukraine
Aon Ukraine LLC	Ukraine
Aon (DIFC) Gulf Limited	United Arab Emirates
Aon Management Services (Middle East) Limited	United Arab Emirates
Aon Middle East Co LLC	United Arab Emirates
Aon Middle East Consulting LLC	United Arab Emirates
Aon Neudorf Finance S.a.r.l. (Dubai branch)	United Arab Emirates
Aon Reinsurance Solutions MENA Limited	United Arab Emirates
Aon Retirement Solutions Limited	United Arab Emirates
Aon Solutions Middle East Limited	United Arab Emirates

Name	Country	State/Province
Aon Solutions Middle East Limited (Abu Dhabi branch)	United Arab Emirates
Cut-e Consult DMCC	United Arab Emirates
McLagan Partners, Inc. (Dubai Branch)	United Arab Emirates
Stroz Friedberg Risk Management Limited	United Arab Emirates
Acumen Credit Insurance Brokers Limited	United Kingdom
Alexander Clay (in liquidation)	United Kingdom
Aon ANZ Holdings Limited	United Kingdom
Aon Assessment (UK) Limited	United Kingdom
Aon Belgium B.V. (UK Branch)	United Kingdom
Aon Consulting Financial Services Limited	United Kingdom
Aon Consulting Limited	United Kingdom
Aon DC Trustee Limited	United Kingdom
Aon Delta UK Limited	United Kingdom
Aon Finance UK 1 Limited	United Kingdom
Aon Finance UK 2 Limited	United Kingdom
Aon Finance UK 3 Limited	United Kingdom
Aon Finance UK 4 Limited	United Kingdom
Aon Global Holdings 1 Limited	United Kingdom
Aon Global Holdings 2 Limited	United Kingdom
Aon Global Holdings Intermediaries Limited	United Kingdom
Aon Global Holdings plc	United Kingdom
Aon Global Limited	United Kingdom
Aon Holdings Limited	United Kingdom
Aon Investments Europe Limited ( in liquidation)	United Kingdom
Aon Investments Limited	United Kingdom
Aon Minet Pension Trustees Limited	United Kingdom
Aon Overseas Holdings Limited	United Kingdom
Aon Pension Trustees Limited	United Kingdom

Name	Country	State/Province
Aon Randolph UK Limited	United Kingdom
Aon Risk Services (NI) Limited	United Kingdom
Aon Securities Limited	United Kingdom
Aon Solutions UK Limited	United Kingdom
Aon Southern Europe UK Limited	United Kingdom
Aon Trust Corporation Limited	United Kingdom
Aon UK Group Limited	United Kingdom
Aon UK Holdings Intermediaries Limited	United Kingdom
Aon UK Holdings Limited	United Kingdom
Aon UK Limited	United Kingdom
Aon UK Trustees Limited	United Kingdom
Aon US & International Holdings Limited	United Kingdom
Bacon & Woodrow Partnerships Limited	United Kingdom
Beaubien Finance Limited	United Kingdom
Beaubien UK Finance Limited	United Kingdom
Benton Finance Limited	United Kingdom
Contractsure Limited	United Kingdom
CoSec 2000 Limited	United Kingdom
Doveland Services Limited	United Kingdom
E. W. Blanch Holdings Limited	United Kingdom
Eurotempest Limited	United Kingdom
Gotham Digital Science Ltd	United Kingdom
Henderson Insurance Brokers Limited	United Kingdom
Henderson Risk Management Limited (in liquidation)	United Kingdom
International Space Brokers Europe Limited	United Kingdom
International Space Brokers Limited	United Kingdom
McLagan (Aon) Limited	United Kingdom
McLagan Partners, Inc. (UK Branch)	United Kingdom

Name	Country	State/Province
Minet Group	United Kingdom
NBS Nominees Limited	United Kingdom
One Underwriting B.V. (UK branch)	United Kingdom
Portus Consulting Limited (in liquidation)	United Kingdom
Portus Online LLP (in liquidation)	United Kingdom
SLE Worldwide Limited	United Kingdom
Stroz Friedberg Limited	United Kingdom
The Aon MasterTrustee Limited	United Kingdom
Townsend Group Europe Limited	United Kingdom
Aon Latin America S.A.	Uruguay
Marinaro Dundas SA	Uruguay
Access Plans USA, Inc.	USA	Oklahoma
Affinity Insurance Services, Inc.	USA	Pennsylvania
AIS Affinity Insurance Agency, Inc.	USA	California
AIS Insurance Agency, Inc.	USA	Washington
Alexander Reinsurance Intermediaries, Inc.	USA	New York
Allen Insurance Associates, Inc.	USA	California
Alliance HealthCard of Florida, Inc.	USA	Georgia
Alliance HealthCard, Inc.	USA	Georgia
American Insurance Services Corp.	USA	Texas
American Special Risk Insurance Company	USA	Delaware
AMXH, LLC	USA	Delaware
Aon Advantage Funds Holding Corporation	USA	Delaware
Aon Advantage Funds LLC	USA	Delaware
Aon Benefit Solutions Inc.	USA	Oklahoma
Aon Chile Holdings, LLC	USA	Delaware
Aon Consulting & Insurance Services	USA	California
Aon Consulting, Inc.	USA	New Jersey

Name	Country	State/Province
Aon Consulting, Inc.	USA	New York
Aon Corporation	USA	Delaware
Aon Edge Insurance Agency, Inc.	USA	Florida
Aon Fac, Inc.	USA	Illinois
Aon Finance US 1, LLC	USA	Delaware
Aon Finance US 2, LLC	USA	Delaware
Aon Financial & Insurance Solutions, Inc.	USA	California
Aon Foundation - Not For Profit Corporation	USA	Illinois
Aon Group, Inc.	USA	Maryland
Aon Insurance Agency LLC	USA	Delaware
Aon Insurance Managers (USA) Inc.	USA	Vermont
Aon Insurance Managers (USVI), Inc.	USA	US Virgin Islands
Aon International Holdings, Inc.	USA	Maryland
Aon Investments USA Inc.	USA	Illinois
Aon IP Advantage Blocker LLC	USA	Delaware
Aon IP Advantage Fund GP LLC	USA	Delaware
Aon IP Advantage Fund LP	USA	Delaware
Aon KHF Fund GP LLC	USA	Delaware
Aon Life Agency of Texas, Inc.	USA	Texas
Aon Mexico Holdings, LLC	USA	Delaware
Aon North America, Inc.	USA	Delaware
Aon Premium Finance, LLC	USA	Delaware
Aon Private Risk Management Insurance Agency, Inc.	USA	Illinois
Aon Property Risk Consulting, Inc.	USA	New York
Aon Re, Inc.	USA	Illinois
Aon Realty Services, Inc.	USA	Pennsylvania
Aon Reinsurance Holdings, Inc.	USA	Delaware
Aon Retirement Plan Advisors, LLC	USA	Delaware

Name	Country	State/Province
Aon Risk Consultants, Inc.	USA	Illinois
Aon Risk Insurance Services West, Inc.	USA	California
Aon Risk Services (Holdings) of Latin America, Inc.	USA	Delaware
Aon Risk Services (Holdings) of the Americas, Inc.	USA	Illinois
Aon Risk Services Central, Inc.	USA	Illinois
Aon Risk Services Companies, Inc.	USA	Maryland
Aon Risk Services Northeast, Inc.	USA	New York
Aon Risk Services South, Inc.	USA	North Carolina
Aon Risk Services Southwest, Inc.	USA	Texas
Aon Risk Services, Inc. of Florida	USA	Florida
Aon Risk Services, Inc. of Hawaii	USA	Hawaii
Aon Risk Services, Inc. of Maryland	USA	Maryland
Aon Risk Services, Inc. of Washington, D.C.	USA	District of Columbia
Aon Securities LLC	USA	Delaware
Aon Service Corporation	USA	Illinois
Aon Services Group, Inc.	USA	Delaware
Aon Solutions US, LLC	USA	Delaware
Aon Special Risk Resources, Inc.	USA	Delaware
Aon TC Holdings, Inc.	USA	New Jersey
Aon Trust Company LLC	USA	Illinois
Aon Underwriting Managers, Inc.	USA	Delaware
Aon US Holdings 2, Inc.	USA	Delaware
Aon US Holdings, Inc.	USA	Delaware
Aon Ward Financial Corporation	USA	Ohio
Aon/Albert G. Ruben Insurance Services, Inc.	USA	California
ARM International Corp.	USA	New York
ARM International Insurance Agency Corp.	USA	Ohio
ARMRISK CORP.	USA	New Jersey

Name	Country	State/Province
AS Holdings, Inc.	USA	Delaware
ASPN Insurance Agency, LLC	USA	Delaware
Association of Rural and Small Town Americans	USA	Missouri
Assurance Licensing Services, Inc.	USA	Illinois
B E P International Corp.	USA	New Jersey
Benefit Marketing Solutions, L.L.C.	USA	Oklahoma
Blanch Americas, Inc.	USA	Delaware
BMS Insurance Agency, L.L.C.	USA	Oklahoma
Bowes & Company, Inc., of New York	USA	New York
Cammack Health LLC	USA	New York
Cananwill Corporation	USA	Delaware
Cananwill, Inc.	USA	California
Cananwill, Inc.	USA	Pennsylvania
CEREP III Secondary Manager, LLC	USA	Delaware
CFSSG Real Estate Partners I, LLC	USA	Delaware
CFSSG Real Estate Partners II, LLC	USA	Delaware
CIF-H GP LLC	USA	Delaware
Citadel Insurance Managers, Inc.	USA	California
Coalition for Benefits Equality and Choice	USA	California
CoverWallet Science, Inc.	USA	Delaware
CoverWallet, Inc.	USA	Delaware
Crescent Meadow, LLC	USA	Delaware
Custom Benefit Programs, Inc.	USA	New Jersey
cut-e USA Inc.	USA	New York
E.W. Blanch International, Inc.	USA	Delaware
Elysium Digital, L.L.C.	USA	Delaware
Farmington Administrative Services, LLC	USA	Connecticut
Financial & Professional Risk Solutions, Inc.	USA	Illinois

Name	Country	State/Province
Futurity Group, Inc.	USA	Nevada
Gotham Digital Science, LLC	USA	Delaware
GPE IV Korea Feeder General Partner, LLC	USA	Delaware
Grant Park Capital, LLC	USA	Delaware
GTCR/AAM Blocker Corp.	USA	Delaware
HCI Townsend USA Fund Managers LLC	USA	Delaware
Healthy Paws Pet Insurance LLC	USA	Washington
Huntington T. Block Insurance Agency, Inc.	USA	District of Columbia
Impact Forecasting, L.L.C.	USA	Illinois
INPOINT, INC.	USA	Illinois
International Risk Management (Americas), Inc.	USA	Ohio
International Space Brokers, Inc.	USA	Virginia
IRM/GRC Holding Inc.	USA	Delaware
JDPT Manager, LLC	USA	Delaware
Johnson Rooney Welch, Inc.	USA	California
K & K Insurance Group, Inc.	USA	Indiana
KHF Fund, LP	USA	Delaware
KKT GP, LLC	USA	Delaware
KVT GP, LLC	USA	Delaware
Lake Tahoe II GP, LLC	USA	Delaware
Lake Tahoe III GP, LLC	USA	Delaware
Lake Tahoe IV GP, LLC	USA	Delaware
McLagan Partners Asia, Inc.	USA	Delaware
McLagan Partners, Inc.	USA	Delaware
Membership Leasing Trust	USA	Delaware
Minet Holdings Inc.	USA	New York
Minet Re North America, Inc.	USA	Georgia
Modern Survey, Inc.	USA	Minnesota

Name	Country	State/Province
Muirfield Underwriters, Ltd.	USA	Delaware
NJM Fund GP, LLC	USA	Delaware
Paragon Strategic Solutions Inc.	USA	Delaware
PathWise Solutions Group LLC	USA	Delaware
Penn Square I, LLC	USA	Delaware
Penn Square II, LLC	USA	Delaware
Penn Square Manager I, LLC	USA	Delaware
Penn Square Manager II, LLC	USA	Delaware
PGOF I, LLC	USA	Delaware
PGOF Manager I, LLC	USA	Ohio
Premier Auto Finance, Inc.	USA	Delaware
Private Equity Partnership Structures I, LLC	USA	Delaware
Protective Marketing Enterprises, Inc.	USA	Tennessee
SA Special Situations General Partner, LLC	USA	Delaware
Scritch Inc.	USA	Texas
Specialty Benefits, Inc.	USA	Indiana
Strategic Manager-III, LLC	USA	Delaware
Stroz Friedberg Inc.	USA	Delaware
Stroz Friedberg Investigations LLC	USA	Delaware
Stroz Friedberg, LLC	USA	New York
The Key West Saxon Group, LLC	USA	Florida
The Townsend Group, LLC	USA	Ohio
Townsend Alpha Manager I, LLC	USA	Delaware
Townsend Alpha Manager II, LLC	USA	Delaware
Townsend Alpha Manager III, LLC	USA	Delaware
Townsend Great Lakes and Plains GP, LLC	USA	Delaware
Townsend Group Advisors, LLC	USA	Delaware
Townsend Holdings LLC	USA	Delaware

Name	Country	State/Province
Townsend Opportunity Zone Fund GP, LLC	USA	Delaware
Townsend REF GP, LLC	USA	Delaware
Townsend Strategic Ventures GP, LLC	USA	Delaware
TownSquare Alpha Manager I-A, LLC	USA	Delaware
TTG Core Plus Investments, LLC	USA	Delaware
TTG German Investments I, LLC	USA	Ohio
TTG Manager, LLC	USA	Delaware
Underwriters Marine Services, Inc.	USA	Louisiana
Ward Financial Group, Inc.	USA	Ohio
West Lake General Partner, LLC	USA	Delaware
West Lake II GP, LLC	USA	Delaware
White Rock (District of Columbia) PCC Ltd.	USA	District of Columbia
White Rock USA Ltd.	USA	Vermont
Worldwide Integrated Services Company	USA	Texas
Wrapid Specialty, Inc.	USA	California
WT Government Services, LLC	USA	Delaware
WT Technologies, LLC	USA	Delaware
Administradora Aon, C.A.	Venezuela
Aon Group Venezuela, Corretaje de Reaseguros, C.A.	Venezuela
Aon Risk Services Venezuela, Corretaje de Seguros C.A.	Venezuela
Aon Vietnam Limited	Vietnam

EX-22.1

Exhibit 22.1

Subsidiary Guarantors and Issuers of Guaranteed Securities

The table below sets forth the respective issuers, co-issuers, and guarantors of the notes issued by Aon Global Limited, Aon Global Holdings plc, and Aon Corporation and the jurisdiction of incorporation of each such entity.

		Aon Corporation	Aon Global Limited	Aon Corporation and Aon Global Holdings plc
Entity	Jurisdiction of Incorporation	2.20% Senior Notes due 2022 8.205% Junior Subordinated Notes due 2027 4.50% Senior Notes due 2028 3.75% Senior Notes due 2029 2.80% Senior Notes due 2030 6.25% Senior Notes due 2040	4.00% Senior Notes due 2023 3.50% Senior Notes due 2024 3.875% Senior Notes due 2025 2.875% Senior Notes due 2026 4.25% Senior Notes due 2042 4.45% Senior Notes due 2043 4.60% Senior Notes due 2044 4.75% Senior Notes due 2045	2.05% Senior Notes due 2031 2.60% Senior Notes due 2031 2.90% Senior Notes due 2051
Aon plc	Ireland	Guarantor	Guarantor	Guarantor
Aon Global Limited	UK	Guarantor	Issuer	Guarantor
Aon Global Holdings plc	UK	Guarantor	Guarantor	Co-Issuer
Aon Corporation	US	Issuer	Guarantor	Co-Issuer

EX-23

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the following Registration Statements:

Registration Statement
Form	Number	Purpose
S-8	333-55773	Pertaining to Aon's stock award plan, stock option plan, and employee stock purchase plan
S-4	333-168320	Pertaining to the registration of 4,545,566 shares of common stock registered on Post Effective Amendment No. 1 related to the Amended and Restated Global Stock and Incentive Compensation Plan of Hewitt Associates, Inc.
S-8	333-103344	Pertaining to the Aon Stock Incentive Plan
S-8	333-106584	Pertaining to Aon's deferred compensation plan
S-8	333-145928	Pertaining to the Aon Stock Incentive Plan
S-8	333-145930	Pertaining to the registration of common stock underlying equity securities issued to Aon's president and chief executive officer
S-8	333-174788	Pertaining to Aon's 2011 stock incentive plan and 2011 employee stock purchase plan
S-4	333-178991	Pertaining to the registration of 355,110,708 Class A Ordinary Shares of Aon Global Limited, and in the related Proxy Statement / Prospectus of Aon Global and Aon Corporation contained therein
S-8	333-184999	Pertaining to Aon plc Company Share Save Plan
S-8	333-199759	Pertaining to the registration of an additional 9,000,000 Class A Ordinary Shares to be issued pursuant to the Aon plc 2011 Incentive Plan
S-8	333-235296	Pertaining to the registration of an additional 5,000,000 Class A Ordinary Shares to be issued pursuant to the Aon plc 2011 Incentive Plan
S-3	333-238189	Pertaining to the registration of debt securities, preference shares, Class A Ordinary Shares, share purchase contracts and share purchase units of Aon plc, debt securities of Aon Global Holdings plc, senior debt securities of Aon Corporation, and the related guarantees of each of Aon plc, AGH, Aon Corporation and Aon plc

of our reports dated February 18, 2022, with respect to the consolidated financial statements of Aon plc and the effectiveness of internal control over financial reporting of Aon plc, included in this Annual Report (Form 10-K) of Aon plc for the year ended December 31, 2021.

Chicago, Illinois

February 18, 2022

EX-31.1

Exhibit 31.1

CERTIFICATIONS

I, Gregory C. Case, the Chief Executive Officer of Aon plc, certify that:

1.     I have reviewed this annual report on Form 10-K of Aon plc;

2.     Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.     Based on my knowledge, the financial statements and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.     The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)     Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)     Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)     Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)     Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.     The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)     All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)     Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

		/s/ GREGORY C. CASE
Date:	February 18, 2022	Gregory C. Case Chief Executive Officer

EX-31.2

Exhibit 31.2

CERTIFICATIONS

I, Christa Davies, the Chief Financial Officer of Aon plc, certify that:

1.     I have reviewed this annual report on Form 10-K of Aon plc;

2.     Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.     Based on my knowledge, the financial statements and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.     The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)     Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)     Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)     Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)     Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.     The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)     All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)     Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

		/s/ CHRISTA DAVIES
Date:	February 18, 2022	Christa Davies Chief Financial Officer

EX-32.1

Exhibit 32.1

Certification Pursuant to Section 1350 of Chapter 63

of Title 18 of the United States Code

    I, Gregory C. Case, the Chief Executive Officer of Aon plc (the "Company"), certify that (i) the Annual Report on Form 10-K of the Company for the year ended December 31, 2021 (the "Report") fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and (ii) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ GREGORY C. CASE

Gregory C. Case
Chief Executive Officer

February 18, 2022

EX-32.2

Exhibit 32.2

Certification Pursuant to Section 1350 of Chapter 63

of Title 18 of the United States Code

    I, Christa Davies, the Chief Financial Officer of Aon plc (the "Company"), certify that (i) the Annual Report on Form 10-K of the Company for the year ended December 31, 2021 (the "Report") fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and (ii) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ CHRISTA DAVIES

Christa Davies
Chief Financial Officer

February 18, 2022

XML

Cover - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 17, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-7933
Entity Registrant Name	Aon plc
Entity Incorporation, State or Country Code	L2
Entity Tax Identification Number	98-1539969
Entity Address, Address Line One	Metropolitan Building, James Joyce Street
Entity Address, City or Town	Dublin 1
Entity Address, Country	IE
Entity Address, Postal Zip Code	D01 K0Y8
City Area Code	1
Local Phone Number	266 6000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 53,867,751,208
Entity Common Stock, Shares Outstanding		213,944,460
Documents Incorporated by Reference	Portions of the registrant’s proxy statement for its 2022 Annual General Meeting of Shareholders are incorporated by reference in this report in response to Part III, Items 10, 11, 12, 13, and 14.
Entity Central Index Key	0000315293
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Class A Ordinary Shares, $0.01 nominal value
Entity Information [Line Items]
Title of 12(b) Security	Class A Ordinary Shares, $0.01 nominal value
Trading Symbol	AON
Security Exchange Name	NYSE
Guarantees of Aon plc’s 4.00% Senior Notes due 2023
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 4.00% Senior Notes due 2023
Trading Symbol	AON23
Security Exchange Name	NYSE
Guarantees of Aon plc’s 3.50% Senior Notes due 2024
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 3.50% Senior Notes due 2024
Trading Symbol	AON24
Security Exchange Name	NYSE
Guarantees of Aon plc’s 3.875% Senior Notes due 2025
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 3.875% Senior Notes due 2025
Trading Symbol	AON25
Security Exchange Name	NYSE
Guarantees of Aon plc’s 2.875% Senior Notes due 2026
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 2.875% Senior Notes due 2026
Trading Symbol	AON26
Security Exchange Name	NYSE
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.05% Senior Notes due 2031
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.05% Senior Notes due 2031
Trading Symbol	AON31
Security Exchange Name	NYSE
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.60% Senior Notes due 2031
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.60% Senior Notes due 2031
Trading Symbol	AON31A
Security Exchange Name	NYSE
Guarantees of Aon plc’s 4.25% Senior Notes due 2042
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 4.25% Senior Notes due 2042
Trading Symbol	AON42
Security Exchange Name	NYSE
Guarantees of Aon plc’s 4.45% Senior Notes due 2043
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 4.45% Senior Notes due 2043
Trading Symbol	AON43
Security Exchange Name	NYSE
Guarantees of Aon plc’s 4.60% Senior Notes due 2044
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 4.60% Senior Notes due 2044
Trading Symbol	AON44
Security Exchange Name	NYSE
Guarantees of Aon plc’s 4.75% Senior Notes due 2045
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon plc’s 4.75% Senior Notes due 2045
Trading Symbol	AON45
Security Exchange Name	NYSE
Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.90% Senior Notes due 2051
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.90% Senior Notes due 2051
Trading Symbol	AON51
Security Exchange Name	NYSE

XML

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Location	Chicago, Illinois
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP

XML

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue
Total revenue	$ 12,193	$ 11,066	$ 11,013
Expenses
Compensation and benefits	6,738	5,905	6,054
Information technology	477	444	494
Premises	327	291	339
Depreciation of fixed assets	179	167	172
Amortization and impairment of intangible assets	147	246	392
Other general expense	2,235	1,232	1,393
Total operating expenses	10,103	8,285	8,844
Operating income	2,090	2,781	2,169
Interest income	11	6	8
Interest expense	(322)	(334)	(307)
Other income	152	13	0
Income before income taxes	1,931	2,466	1,870
Income tax expense	623	448	297
Net income	1,308	2,018	1,573
Less: Net income attributable to noncontrolling interests	53	49	41
Net income attributable to Aon shareholders	$ 1,255	$ 1,969	$ 1,532
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 5.59	$ 8.49	$ 6.42
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 5.55	$ 8.45	$ 6.37
Weighted average ordinary shares outstanding - basic (in shares)	224.7	231.9	238.6
Weighted average ordinary shares outstanding - diluted (in shares)	226.1	233.1	240.6

XML

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 1,308	$ 2,018	$ 1,573
Less: Net income attributable to noncontrolling interests	53	49	41
Net income attributable to Aon shareholders	1,255	1,969	1,532
Other comprehensive income (loss), net of tax:
Change in fair value of financial instruments	1	13	3
Foreign currency translation adjustments	(289)	263	14
Postretirement benefit obligation	277	(101)	(141)
Total other comprehensive income (loss)	(11)	175	(124)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(1)	3	0
Total other comprehensive income (loss) attributable to Aon shareholders	(10)	172	(124)
Comprehensive income attributable to Aon shareholders	$ 1,245	$ 2,141	$ 1,408

XML

Consolidated Statements of Financial Position - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 544	$ 884
Short-term investments	292	308
Receivables, net	3,094	3,070
Fiduciary assets	14,386	13,798
Other current assets	716	624
Total current assets	19,032	18,684
Goodwill	8,434	8,666
Intangible assets, net	492	640
Fixed assets, net	529	599
Operating lease right-of-use assets	786	911
Deferred tax assets	766	724
Prepaid pension	1,366	1,280
Other non-current assets	512	610
Total assets	31,917	32,114
Current liabilities
Accounts payable and accrued liabilities	2,192	2,016
Short-term debt and current portion of long-term debt	1,164	448
Fiduciary liabilities	14,386	13,798
Other current liabilities	1,331	1,171
Total current liabilities	19,073	17,433
Long-term debt	8,228	7,281
Non-current operating lease liabilities	772	897
Deferred tax liabilities	401	262
Pension, other postretirement, and postemployment liabilities	1,375	1,763
Other non-current liabilities	910	895
Total liabilities	30,759	28,531
Equity
Ordinary shares - $0.01 nominal value Authorized: 500.0 shares (issued: 2021 - 214.8; 2020 - 225.5)	2	2
Additional paid-in capital	6,624	6,312
Retained earnings (accumulated deficit)	(1,694)	1,042
Accumulated other comprehensive loss	(3,871)	(3,861)
Total Aon shareholders' equity	1,061	3,495
Noncontrolling interests	97	88
Total equity	1,158	3,583
Total liabilities and equity	$ 31,917	$ 32,114

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Consolidated Statements of Financial Position (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Ordinary shares, nominal value (in dollars per share)	$ 0.01	$ 0.01
Ordinary shares, authorized shares (in Shares)	500,000,000.0	500,000,000.0
Ordinary shares, issued shares (in Shares)	214,800,000	225,500,000

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Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Ordinary Shares and Additional Paid-in Capital	Ordinary Shares and Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Loss, Net of Tax	Accumulated Other Comprehensive Loss, Net of Tax Cumulative Effect, Period of Adoption, Adjusted Balance	Non-controlling Interests	Non-controlling Interests Cumulative Effect, Period of Adoption, Adjustment	Non-controlling Interests Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning Balance (in shares) at Dec. 31, 2018				240.1
Beginning Balance at Dec. 31, 2018	$ 4,219			$ 5,967		$ 2,093			$ (3,909)		$ 68
Increase (Decrease) in Shareholders' Equity
Net income	1,573					1,532					41
Shares issued — employee stock compensation plans (in shares)				2.5
Shares issued — employee stock compensation plans	(131)			$ (130)		(1)
Shares purchased (in shares)				(10.5)
Shares purchased	(1,960)					(1,960)
Share-based compensation expense	317			$ 317
Dividends to shareholders	(410)					(410)
Net change in fair value of financial instruments	3								3
Net foreign currency translation adjustments	14								14
Net postretirement benefit obligation	(141)								(141)
Dividends paid to noncontrolling interests on subsidiary common stock	$ (35)										(35)
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]
Ending Balance (in shares) at Dec. 31, 2019				232.1	232.1
Ending Balance at Dec. 31, 2019	$ 3,449	$ (6)	$ 3,443	$ 6,154	$ 6,154	1,254	$ (6)	$ 1,248	(4,033)	$ (4,033)	74	$ 0	$ 74
Increase (Decrease) in Shareholders' Equity
Net income	2,018					1,969					49
Shares issued — employee stock compensation plans (in shares)				1.9
Shares issued — employee stock compensation plans	(154)			$ (154)
Shares purchased (in shares)				(8.5)
Shares purchased	(1,763)					(1,763)
Share-based compensation expense	317			$ 317
Dividends to shareholders	(412)					(412)
Net change in fair value of financial instruments	13								13
Net foreign currency translation adjustments	263								260		3
Net postretirement benefit obligation	(101)								(101)
Dividends paid to noncontrolling interests on subsidiary common stock	(32)										(32)
Net purchases of shares from noncontrolling interests	$ (9)			$ (3)							(6)
Ending Balance (in shares) at Dec. 31, 2020	225.5			225.5
Ending Balance at Dec. 31, 2020	$ 3,583			$ 6,314		1,042			(3,861)		88
Increase (Decrease) in Shareholders' Equity
Net income	1,308					1,255					53
Shares issued — employee stock compensation plans (in shares)				1.7
Shares issued — employee stock compensation plans	(130)			$ (129)		(1)
Shares purchased (in shares)				(12.4)
Shares purchased	(3,543)					(3,543)
Share-based compensation expense	449			$ 449
Dividends to shareholders	(447)					(447)
Net change in fair value of financial instruments	1								1
Net foreign currency translation adjustments	(289)								(288)		(1)
Net postretirement benefit obligation	277								277
Dividends paid to noncontrolling interests on subsidiary common stock	(38)										(38)
Net purchases of shares from noncontrolling interests	$ (13)			$ (8)							(5)
Ending Balance (in shares) at Dec. 31, 2021	214.8			214.8
Ending Balance at Dec. 31, 2021	$ 1,158			$ 6,626		$ (1,694)			$ (3,871)		$ 97

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Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends (in dollars per share)	$ 1.99	$ 1.78	$ 1.72

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Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net income	$ 1,308	$ 2,018	$ 1,573
Adjustments to reconcile net income to cash provided by operating activities:
Gain from sales of businesses and investments	(142)	(25)	(13)
Depreciation of fixed assets	179	167	172
Amortization and impairment of intangible assets	147	246	392
Share-based compensation expense	449	312	317
Deferred income taxes	11	9	(36)
Change in assets and liabilities:
Receivables, net	(119)	108	(371)
Accounts payable and accrued liabilities	264	186	(28)
Current income taxes	200	(17)	(20)
Pension, other postretirement and postemployment liabilities	(119)	(141)	(156)
Other assets and liabilities	4	(80)	5
Cash provided by operating activities	2,182	2,783	1,835
Cash flows from investing activities
Proceeds from investments	58	64	61
Payments for investments	(91)	(97)	(113)
Net sales (purchases) of short-term investments - non fiduciary	15	(167)	35
Acquisition of businesses, net of cash and funds held on behalf of clients	(14)	(368)	(39)
Sale of businesses, net of cash and funds held on behalf of clients	218	30	52
Capital expenditures	(137)	(141)	(225)
Cash provided by (used for) investing activities	49	(679)	(229)
Cash flows from financing activities
Share repurchase	(3,543)	(1,763)	(1,960)
Issuance of shares for employee benefit plans	(130)	(149)	(131)
Issuance of debt	5,973	4,153	6,052
Repayment of debt	(4,220)	(3,882)	(4,941)
Increase in fiduciary liabilities, net of fiduciary receivables	568	316	1,246
Cash dividends to shareholders	(447)	(412)	(410)
Noncontrolling interests and other financing activities	(125)	(35)	(103)
Cash used for financing activities	(1,924)	(1,772)	(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(235)	297	63
Net increase in cash and cash equivalents and funds held on behalf of clients	72	629	1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	6,573	5,944	4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	6,645	6,573	5,944
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	544	884	790
Funds held on behalf of clients	6,101	5,689	5,154
Total cash and cash equivalents and funds held on behalf of clients	6,645	6,573	5,944
Supplemental disclosures:
Interest paid	328	326	289
Income taxes paid, net of refunds	$ 412	$ 455	$ 353

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Basis of Presentation

12 Months Ended

Dec. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. The Consolidated Financial Statements include the accounts of Aon plc and all of its controlled subsidiaries (“Aon” or the “Company”). Intercompany accounts and transactions have been eliminated. The Consolidated Financial Statements include, in the opinion of management, all adjustments (consisting of normal recurring adjustments and reclassifications) necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows for all periods presented.

References in this report to “Aon,” the “Company,” “we,” “us,” or “our” for time periods prior to April 1, 2020 refer to Aon Global Limited. References in the Financial Statements to “Aon,” the “Company,” “we,” “us,” or “our” for time periods on or after April 1, 2020, refer to Aon plc.

Reclassification

Certain amounts in the prior year's Consolidated Financial Statements have been reclassified to conform to the current year’s presentation. For the years ended December 31, 2020 and December 31, 2019, there was $1 million of income and $1 million of loss, respectively, including the related tax effect, from discontinued operations recognized in Net Income from discontinued operations in the Consolidated Statements of Income and Consolidated Statements of Cash Flows. These amounts are now included in Other income in the Consolidated Statements of Income and Other assets and liabilities in the Consolidated Statements of Cash Flows for the years ended December 31, 2020 and December 31, 2019. There was no impact to the effective tax rate on Net income or earnings per share in either period.

Additionally, for the years ended December 31, 2020 and December 31, 2019, a cash outflow of $127 million and a cash inflow of $3 million, respectively, was classified as an adjustment to Net income from Restructuring reserves in the Consolidated Statements of Cash Flows. These amounts are now included in Other assets and liabilities in the Consolidated Statements of Cash Flows for the years ended December 31, 2020 and December 31, 2019. There was no impact on Cash provided by operating activities.

Disaggregation of Revenue

In 2021, the Company announced steps to further accelerate its Aon United strategy, which now includes four solution lines: Commercial Risk Solutions, Reinsurance Solutions, Health Solutions, and Wealth Solutions. Disaggregation of revenue by the new solution line’s structure is reflected in Note 3 “Revenue from Contracts with Customers”, where prior period amounts have been reclassified to conform to the current periods’ presentation. The changes in the solution line structure affect only the manner in which the Company's revenue results for the Company’s principal service lines were previously reported and have no impact on the Company's previously reported Consolidated Financial Statements, results of operations, or total organic revenue growth. Refer to Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for more information about the changes in the presentation of our principal service line reporting. The Company continues to operate as one segment that includes all of the Company’s operations, refer to Note 16 “Segment Information” for further information.

Use of Estimates

The preparation of the accompanying Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of reserves and expenses. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management believes its estimates to be reasonable given the current facts available. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, foreign currency exchange rate movements, and the COVID-19 pandemic increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment would, if applicable, be reflected in the Consolidated Financial Statements in future periods.

Revision of Previously Issued Financial Statements

During the fourth quarter of 2021, the Company identified and corrected an immaterial presentation error related to funds held on behalf of clients in the Consolidated Statements of Cash Flows.

Based on an analysis of quantitative and qualitative factors in accordance with SEC Staff Accounting Bulletins 99 “Materiality” and 108 “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements”, the Company concluded that these errors were immaterial, individually and in the aggregate, to the Consolidated Statements of Cash Flows as presented in the Company’s quarterly and annual financial statements previously filed in the Company’s Quarterly Reports on Form 10-Q and Annual Reports on Form 10-K. There was no impact to the Consolidated Statements of Income, Statements of Comprehensive Income, Statements of Financial Position, or Statements of Shareholders’ Equity for any period presented.

In preparing the Company’s Consolidated Statement of Cash Flows for the year ended December 31, 2021, the Company made appropriate revisions to its Consolidated Statements of Cash Flows for historical periods. Such changes are reflected for the years ended December 31, 2020 and 2019, included in these financial statements, and will also be reflected in the historical periods included in the Company’s subsequent quarterly and annual consolidated financial statements.

The impact to the Consolidated Statements of Cash Flows previously filed in Annual Reports on Form 10-K is as follows (in millions):

	Year Ended December 31, 2020						Year Ended December 31, 2019
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	2,783	$	—	$	2,783	$	1,835	$	—	$	1,835
Cash used for investing activities	(679)		—		(679)		(229)		—		(229)
Cash provided by (used for) financing activities	(2,088)		316		(1,772)		(1,493)		1,246		(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	78		219		297		21		42		63
Net increase in cash and cash equivalents and funds held on behalf of clients	94		535		629		134		1,288		1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	790		5,154		5,944		656		3,866		4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	$	884	$	5,689	$	6,573	$	790	$	5,154	$	5,944

The impact to the Consolidated Statements of Cash Flows previously filed in unaudited Quarterly Reports on Form 10-Q is as follows (in millions):

	Three Months Ended March 31, 2021						Six Months Ended June 30, 2021						Nine Months Ended September 30, 2021
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	561	$	—	$	561	$	1,345	$	—	$	1,345	$	1,251	$	—	$	1,251
Cash provided by (used for) investing activities	102		—		102		(27)		—		(27)		(116)		—		(116)
Cash provided by (used for) financing activities	(709)		28		(681)		(1,122)		386		(736)		(1,380)		786		(594)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(16)		(18)		(34)		11		18		29		(30)		(63)		(93)
Net increase (decrease) in cash and cash equivalents and funds held on behalf of clients	(62)		10		(52)		207		404		611		(275)		723		448
Cash and cash equivalents and funds held on behalf of clients at beginning of year	884		5,689		6,573		884		5,689		6,573		884		5,689		6,573
Cash and cash equivalents and funds held on behalf of clients at end of year	$	822	$	5,699	$	6,521	$	1,091	$	6,093	$	7,184	$	609	$	6,412	$	7,021

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Summary of Significant Accounting Principles and Practices

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Principles and Practices

Summary of Significant Accounting Principles and Practices

Revenue Recognition

The Company generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services provided to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several

factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which the Company acts. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services and (2) fees and commissions for administrative and other services provided to or on behalf of insurers. In Aon’s capacity as an insurance and reinsurance broker, the service promised to the customer is placement of an effective insurance or reinsurance policy, respectively. At the completion of the insurance or reinsurance policy placement process once coverage is effective, the customer has obtained control over the services promised by the Company. Judgment is not typically required when assessing whether the coverage is effective. Fees from clients for advice and consulting services are dependent on the extent and value of the services provided. Payment terms for the Company’s principal service lines are discussed below; the Company believes these terms are consistent with current industry practices. Significant financing components are typically not present in Aon’s arrangements.

The Company recognizes revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, the Company assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, the Company allocates consideration based on their relative fair values.

Costs incurred by the Company in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

The Company has elected to apply practical expedients to not disclose the revenue related to unsatisfied performance obligations if (1) the contract has an original duration of 1 year or less, (2) the Company has recognized revenue for the amount in which it has the right to bill, and (3) the variable consideration is allocated entirely to an unsatisfied performance obligation which is recognized as a series of distinct goods or services that form a single performance obligation.

Disaggregation of Revenue

The following is a description of principal service lines from which the Company generates its revenue:

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units transferred and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly, over the term of the arrangement in installments based on deposit or minimum premiums for most treaty reinsurance arrangements.

Health Solutions includes consulting and brokerage, Human Capital, and voluntary benefits and enrollment solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services using input or output measures, including units delivered or time elapsed, to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue from health care exchange arrangements is typically recognized upon successful enrollment

of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

Wealth Solutions includes retirement consulting and pension administration, as well as investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services, or for certain arrangements, at a point in time upon completion of the services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Share-based Compensation Expense

Share-based payments to employees, including grants of RSUs and PSAs, are measured based on grant date fair value. For purposes of measuring share-based compensation expense, the Company considered whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2021, 2020, or 2019. The Company recognizes compensation expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs materially from original estimates.

Pension and Other Postretirement Benefits

The Company records net periodic cost relating to its pension and other postretirement benefit plans based on calculations that include various actuarial assumptions, including discount rates, assumed rates of return on plan assets, inflation rates, mortality rates, compensation increases, and turnover rates. The Company reviews its actuarial assumptions on an annual basis and modifies these assumptions based on current rates and trends. The effects of gains, losses, and prior service costs and credits are amortized over future service periods or future estimated lives if the plans are frozen as reflected in Other income within the Consolidated Statements of Income. The funded status of each plan, calculated as the fair value of plan assets less the benefit obligation, is reflected in the Company’s Consolidated Statements of Financial Position using a December 31 measurement date.

Earnings per Share

Basic earnings per share is computed by dividing net income available to ordinary shareholders by the weighted-average number of ordinary shares outstanding, including participating securities, which consist of unvested share awards with non-forfeitable rights to dividends. Diluted earnings per share is computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding, which have been adjusted for the dilutive effect of potentially issuable ordinary shares, including certain contingently issuable shares. The diluted earnings per share calculation reflects the more dilutive effect of either (1) the two-class method that assumes that the participating securities have not been exercised, or (2) the treasury stock method.

Potentially issuable shares are not included in the computation of diluted earnings per share if their inclusion would be antidilutive.

Cash and Cash Equivalents and Short-term Investments

Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments consist of money market funds. The estimated fair value of Cash and cash equivalents and Short-term investments approximates their carrying values.

At December 31, 2021, Cash and cash equivalents and Short-term investments totaled $836 million compared to $1,192 million at December 31, 2020, a decrease of $356 million. Of the total balance, $160 million and $102 million was restricted as to its use at December 31, 2021 and 2020, respectively. Included within Short-term investments as of December 31, 2021 and 2020 balances, respectively, were £84.3 million ($112.8 million at December 31, 2021 exchanges rates) and £44.4 million ($60.2

million at December 31, 2020 exchange rates) of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator. During 2021, following discussions with the FCA, and to take into consideration the potential future effects from market volatility due to COVID-19, the Company changed the basis of calculating its liquidity requirement and increased the amount of funds held by £34.3 million ($45.9 million at December 31, 2021 exchange rates).

Fiduciary Assets and Liabilities

In its capacity as an insurance agent and broker, Aon collects premiums from insureds and, after deducting its commission, remits the premiums to the respective insurers. Aon also collects claims or refunds from insurers on behalf of insureds. Uncollected premiums from insureds and uncollected claims or refunds from insurers are recorded as Fiduciary assets in the Company’s Consolidated Statements of Financial Position. Unremitted insurance premiums and claims are held in a fiduciary capacity and the obligation to remit these funds is recorded as Fiduciary liabilities in the Consolidated Statements of Financial Position.

Funds held on behalf of clients represent fiduciary assets held by Aon for premiums collected from insureds but not yet remitted to insurance companies and claims collected from insurance companies but not yet remitted to insureds of $6.1 billion and $5.7 billion at December 31, 2021 and 2020, respectively. Fiduciary receivables were $8.3 billion and $8.1 billion at December 31, 2021 and 2020, respectively. These funds and a corresponding liability are included in Fiduciary assets and Fiduciary liabilities, respectively, in the accompanying Consolidated Statements of Financial Position.

Allowance for Doubtful Accounts

The Company’s estimate for allowance for credit losses with respect to receivables is based on a combination of factors, including evaluation of forward-looking information, historical write-offs, aging of balances, and other qualitative and quantitative analyses. Receivables, net included an allowance for doubtful accounts of $90 million and $98 million at December 31, 2021 and 2020, respectively.

Fixed Assets

Fixed assets are stated at cost, less accumulated depreciation. Included in this category are certain capitalized costs incurred during the application development stage related to directly obtaining, developing, or enhancing internal use software. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which are generally as follows:

Asset Description	Estimated Useful Life
Software	Lesser of the life of an associated license, or 4 to 7 years
Leasehold improvements	Lesser of estimated useful life or lease term, not to exceed 10 years
Furniture, fixtures and equipment	4 to 10 years
Computer equipment	4 to 6 years
Buildings	35 years
Automobiles	6 years

Goodwill and Intangible Assets

Goodwill represents the excess of acquisition cost over the fair value of the net assets acquired in the acquisition of a business. Goodwill is allocated to applicable reporting units. Upon disposition of a business entity, goodwill is allocated to the disposed entity based on the fair value of that entity compared to the fair value of the reporting unit in which it was included. Goodwill is not amortized, but instead is tested for impairment at least annually. The goodwill impairment test is performed at the reporting unit level. The Company may initially perform a qualitative analysis to determine if it is more likely than not that the goodwill balance is impaired. If a qualitative assessment is not performed or if a determination is made that it is not more likely than not that their value of the reporting unit exceeds its carrying amount, then the Company will perform a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit. Any resulting difference will be a charge to Amortization and impairment of intangible assets in the Consolidated Statements of Income in the period in which the determination is made. Fair value is determined using a combination of present value techniques and market prices of comparable businesses.

We classify our intangible assets acquired as either tradenames, customer-related and contract-based, or technology and other. Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Derivatives

Derivative instruments are recognized in the Consolidated Statements of Financial Position at fair value. Where the Company has entered into master netting agreements with counterparties, the derivative positions are netted by counterparties and are reported accordingly in other assets or other liabilities. Changes in the fair value of derivative instruments are recognized in earnings each period, unless the derivative is designated and qualifies as a cash flow or net investment hedge.

The Company has historically designated the following hedging relationships for certain transactions: (1) a hedge of the change in fair value of a recognized asset or liability or firm commitment (“fair value hedge”), (2) a hedge of the variability in cash flows from a recognized variable-rate asset or liability or forecasted transaction (“cash flow hedge”), and (3) a hedge of the net investment in a foreign operation (“net investment hedge”).

In order for a derivative to qualify for hedge accounting, the derivative must be formally designated as a fair value, cash flow, or a net investment hedge by documenting the relationship between the derivative and the hedged item. The documentation must include a description of the hedging instrument, the hedged item, the risk being hedged, Aon’s risk management objective and strategy for undertaking the hedge, and the method for assessing the effectiveness of the hedge. Additionally, the hedge relationship must be expected to be highly effective at offsetting changes in either the fair value or cash flows of the hedged item at both the inception of the hedge and on an ongoing basis. Aon assesses the ongoing effectiveness of its hedges quarterly or more frequently if facts and circumstances require.

For a derivative designated as a fair value hedging instrument, the gain or loss is recognized in earnings in the period of change together with the offsetting loss or gain on the hedged item attributable to the risk being hedged. The effect is to reflect in earnings the extent to which the hedge is not effective in achieving offsetting changes in fair value. For a cash flow hedge that qualifies for hedge accounting, the change in fair value of a hedging instrument is recognized in Accumulated Other Comprehensive Income and subsequently reclassified to earnings in the same period the hedged item impacts earnings. For a net investment hedge, the change in fair value of the hedging instrument is recognized in Accumulate Other Comprehensive Income as part of the cumulative translation adjustment.

Changes in the fair value of a derivative that is not designated as part of a hedging relationship (commonly referred to as an “economic hedge”) are recorded in Other income in the Consolidated Statements of Income in the period of change.

The Company discontinues hedge accounting prospectively when (1) the derivative expires or is sold, terminated, or exercised, (2) the qualifying criteria are no longer met, or (3) management removes the designation of the hedging relationship.

Foreign Currency

Certain of the Company’s non-U.S. operations use their respective local currency as their functional currency. These operations that do not have the U.S. dollar as their functional currency translate their financial statements at the current rates of exchange in effect at the balance sheet date and revenues and expenses using rates that approximate those in effect during the period. The resulting translation adjustments are included in Net foreign currency translation adjustments within the Consolidated Statements of Shareholders’ Equity. Further, gains and losses from the remeasurement of monetary assets and liabilities that are denominated in a non-functional currency of that entity are included in Other income within the Consolidated Statements of Income.

Income Taxes

Deferred income taxes are recognized for the effect of temporary differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted marginal tax rates and laws that are currently in effect. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period when the rate change is enacted.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences,

future taxable income exclusive of reversing temporary differences and carry-forwards, taxable income in carry-back years, and tax planning strategies that are both prudent and feasible.

The Company recognizes the effect of income tax positions only if sustaining those positions is more likely than not. Tax positions that meet the more likely than not recognition threshold but are not highly certain are initially and subsequently measured based on the largest amount of benefit that is greater than 50% likely of being realized upon settlement with the taxing authority. Only information that is available at the reporting date is considered in the Company’s recognition and measurement analysis, and events or changes in facts and circumstances are accounted for in the period in which the event or change in circumstance occurs.

The Company records penalties and interest related to unrecognized tax benefits in Income taxes in the Company’s Consolidated Statements of Income.

Leases

The Company leases office facilities, equipment, and automobiles under operating and finance leases. The Company’s lease obligations are primarily for the use of office facilities. The Company evaluates if a leasing arrangement exists upon inception of a contract. A contract contains a lease if the contract conveys the right to control the use of identified tangible assets for a period of time in exchange for consideration. Identified property, plant, or equipment may include a physically distinct portion of a larger asset, or a portion of an asset that represents substantially all of the capacity of the asset but is not physically distinct. The Company assesses whether a contract implicitly contains the right to control the use of a tangible asset that is not already owned. In addition, the Company subleases certain real estate properties to third parties, which are classified as operating leases.

The Company’s leases expire at various dates and may contain renewal, expansion or termination options. The exercise of lease renewal and expansion options are typically at the Company’s sole discretion and are only included in the determination of the lease term if the Company is reasonably certain to exercise the option. In addition, the Company’s lease agreements typically do not contain any material residual value guarantees or restrictive covenants.

ROU assets and lease liabilities are based on the present value of the minimum lease payments over the lease term. The Company has elected the practical expedient related to lease and non-lease components, as an accounting policy election for all asset classes, which allows a lessee to not separate non-lease components from lease components and instead account for consideration received in a contract as a single lease component.

The Company made a policy election to not recognize ROU assets and lease liabilities that arise from leases with an initial term of twelve months or less in the Consolidated Statements of Financial Position. However, the Company recognized these lease payments in the Consolidated Statements of Income on a straight-line basis over the lease term and variable lease payments in the period in which the expense was incurred. The Company chose to apply this accounting policy across all classes of underlying assets.

A portion of the Company’s lease agreements include variable lease payments that are not recorded in the initial measurement of the lease liability and ROU asset balances. For real estate arrangements, base rental payments may be escalated according to annual changes in the CPI or other indices. The escalated rental payments based on the estimated CPI at the lease commencement date are included within minimum rental payments; however, changes in CPI are considered variable in nature and are recognized as variable lease costs in the period in which the obligation is incurred. Additionally, real estate lease agreements may include other variable payments related to operating expenses charged by the landlord based on actual expenditures. Information technology equipment agreements may include variable payments based on usage of the equipment. These expenses are also recognized as variable lease costs in the period in which the expense is incurred.

The Company utilizes discount rates to determine the present value of the lease payments based on information available at the commencement date of the lease. As the rate implicit in each lease is not typically readily available, the Company uses an incremental borrowing rate based on factors such as the lease term and the economic environment where the lease exists to determine the appropriate present value of future lease payments. When determining the incremental borrowing rate, the Company considers the rate of interest it would pay on a secured borrowing in an amount equal to the lease payments for the underlying asset under similar terms.

Operating leases are included in Operating lease ROU assets, Other current liabilities, and Non-current operating lease liabilities in the Consolidated Statements of Financial Position. Finance leases are included in Other non-current assets, Other current liabilities, and Other non-current liabilities in the Consolidated Statements of Financial Position.

Principles of Consolidation

The accompanying Consolidated Financial Statements include the accounts of Aon plc and those entities in which the Company has a controlling financial interest. To determine if Aon holds a controlling financial interest in an entity, the Company first evaluates if it is required to apply the VIE model to the entity, otherwise, the entity is evaluated under the voting interest model. Where Aon holds rights that give it the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, combined with a variable interest that gives the right to receive potentially significant benefits or the obligation to absorb potentially significant losses, the Company has a controlling financial interest in that VIE. The Company does not consolidate the VIEs and Aon’s interest in VIEs as of December 31, 2021 was insignificant. Aon holds a controlling financial interest in entities that are not VIEs where it, directly or indirectly, holds more than 50% of the voting rights or where it exercises control through substantive participating rights or as a general partner.

New Accounting Pronouncements

Adoption of New Accounting Standards

Contract Assets and Contract Liabilities Acquired in a Business Combination

In October 2021, FASB issued new accounting guidance related to the accounting for contract assets and contract liabilities from contracts with customers acquired in a business combination. The new guidance improves the accounting for acquired revenue contracts with customers in a business combination by addressing diversity in practice and inconsistency. The new guidance requires an entity to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with the current accounting standard on revenue from contracts with customers, ASC 606. The new guidance is effective for Aon in the first quarter of 2023, with early adoption permitted. The Company elected to early adopt this guidance in the fourth quarter of 2021. The Company adopted the new guidance on a prospective basis while applying the amendments to all business combinations that occurred during 2021 as required by the new guidance. The early adoption of the new guidance did not have a material impact on the Consolidated Financial Statements.

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Revenue from Contracts with Customers

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Revenue from Contracts with Customers

Revenue from Contracts with Customers

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions). Prior year amounts from the Consolidated Financial Statements have been reclassified to conform to the current year’s presentation. Refer to Note 1 “Basis of Presentation” for further information regarding the changes to the Company’s principal service lines.

	Years Ended December 31
	2021		2020		2019
Commercial Risk Solutions	$	6,635	$	5,861	$	5,857
Reinsurance Solutions	1,997		1,814		1,686
Health Solutions	2,154		2,067		2,104
Wealth Solutions	1,426		1,341		1,380
Elimination	(19)		(17)		(14)
Total revenue	$	12,193	$	11,066	$	11,013

Consolidated revenue from contracts with customers by geographic area, which is attributed on the basis of where the services are performed, is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	5,459	$	5,032	$	5,016
Americas other than U.S.	1,027		911		919
U.K.	1,681		1,579		1,502
Ireland	127		84		75
Europe, Middle East, & Africa other than U.K. and Ireland	2,565		2,236		2,263
Asia Pacific	1,334		1,224		1,238
Total revenue	$	12,193	$	11,066	$	11,013

Contract Costs

Changes in the net carrying amount of costs to fulfill contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	339	$	335
Additions	1,504		1,360
Amortization	(1,478)		(1,360)
Impairment	—		—
Foreign currency translation and other	(4)		4
Balance at end of period	$	361	$	339

Changes in the net carrying amount of costs to obtain contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	184	$	171
Additions	59		61
Amortization	(48)		(47)
Impairment	—		—
Foreign currency translation and other	(16)		(1)
Balance at end of period	$	179	$	184

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Other Financial Data

12 Months Ended

Dec. 31, 2021

Other Financial Data [Abstract]

Other Financial Data

Other Financial Data

Consolidated Statements of Income Information

Other Income

The components of Other income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Foreign currency remeasurement	$	26	$	(12)	$	9
Gain from disposals of business	142		25		13
Pension and other postretirement	21		13		9
Equity earnings	8		4		4
Extinguishment of debt	—		(7)		—
Financial instruments	(45)		(10)		(35)
Total	$	152	$	13	$	—

Consolidated Statements of Financial Position Information

Allowance for Doubtful Accounts

Changes in the net carrying amount of allowance for doubtful accounts are as follows (in millions):

	2021		2020		2019
Balance at beginning of period	$	98	$	70	$	62
Adoption of new accounting guidance (1)	—		7		—
Adjusted balance at beginning of period	98		77		62
Provision	26		29		27
Accounts written off, net of recoveries	(37)		(6)		(19)
Foreign currency translation and other	3		(2)		—
Balance at end of period	$	90	$	98	$	70

(1) The adoption of the new accounting standard on the measurement of credit losses on January 1, 2020 resulted in addition to the Allowance for doubtful accounts of $7 million. After tax impacts, this resulted in a $6 million decrease to Retained earnings. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” for further information.

Other Current Assets

The components of Other current assets are as follows (in millions):

As of December 31	2021		2020
Costs to fulfill contracts with customers(1)	$	361	$	339
Taxes receivable	53		95
Prepaid expenses	137		111
Other	165		79
Total	$	716	$	624

(1)Refer to Note 3 “Revenue from Contracts with Customers” for further information.

Fixed Assets, net

The components of Fixed assets, net are as follows (in millions):

As of December 31	2021		2020
Software	$	797	$	808
Leasehold improvements	425		375
Computer equipment	268		249
Furniture, fixtures and equipment	279		246
Construction in progress	45		155
Other	33		34
Fixed assets, gross	1,847		1,867
Less: Accumulated depreciation	1,318		1,268
Fixed assets, net	$	529	$	599

Depreciation expense, which includes software amortization, was $179 million, $167 million, and $172 million for the years ended December 31, 2021, 2020, and 2019, respectively.

Other Non-current Assets

The components of Other non-current assets are as follows (in millions):

As of December 31	2021		2020
Costs to obtain contracts with customers (1)	$	179	$	184
Investments	64		74
Leases (2)	63		89
Taxes receivable	95		125
Other	111		138
Total	$	512	$	610

(1)    Refer to Note 3 “Revenue from Contracts with Customers” for further information.

(2) Refer to Note 8 “Lease Commitments” for further information.

Other Current Liabilities

The components of Other current liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred revenue (1)	$	321	$	296
Taxes payable	149		80
Leases (2)	213		234
Other	648		561
Total	$	1,331	$	1,171

(1)$553 million and $454 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2021 and December 31, 2020, respectively.

(2)Refer to Note 8 “Lease Commitments” for further information.

Other Non-current Liabilities

The components of Other non-current liabilities are as follows (in millions):

As of December 31	2021		2020
Taxes payable (1)	$	609	$	561
Leases (2)	46		65
Compensation and benefits	58		53
Deferred revenue	70		76
Other	127		140
Total	$	910	$	895

(1)Includes $145 million for the non-current portion of the transition tax as of December 31, 2021 and December 31, 2020. Refer to Note 9 “Income Taxes” for further information on the transition tax.

(2)Refer to Note 8 “Lease Commitments” for further information.

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Acquisitions and Dispositions of Businesses

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

Acquisitions and Dispositions of Businesses

Acquisitions and Dispositions of Businesses

Completed Acquisitions

The Company completed two acquisitions during the year ended December 31, 2021 and six acquisitions during the year ended December 31, 2020. The following table includes the preliminary fair values of consideration transferred, assets acquired, and liabilities assumed as a result of the Company’s acquisitions (in millions):

	Year Ended December 31, 2021
Consideration transferred
Cash	$	27
Deferred, contingent, and other consideration	17
Aggregate consideration transferred	$	44
Assets acquired
Goodwill	17
Other intangible assets	13
Other assets (1)	26
Total assets acquired	56
Liabilities assumed
Total liabilities assumed	12
Net assets acquired	$	44

(1)     In the year ended December 31, 2021, cash and cash equivalents of $12 million and funds held on behalf of client of $1 million were acquired.

Intangible assets acquired include customer-related and contract-based assets. The intangible assets acquired as part of business acquisitions in 2021 had a weighted average useful economic life of 9 years. Acquisition related costs for completed acquisitions incurred and recognized within Other general expense for the year ended December 31, 2021 were insignificant.

The results of operations of these acquisitions are included in the Consolidated Financial Statements as of the respective acquisition dates. The Company’s results of operations would not have been materially different if these acquisitions had been reported from the beginning of the period in which they were acquired.

2021 Acquisitions

On December 22, 2021, the Company completed the transaction to acquire 100% share capital of For Welfare S.r.l, a company focused on bancassurance programs in Italy.

On September 1, 2021, the Company completed the transaction to acquire 51% of Aon India Insurance Brokers Limited (formerly known as Anviti Insurance Brokers Private Limited). Prior to the acquisition date, the Company accounted for its 49% interest in Anviti as an equity-method investment. The acquisition-date fair value of the previous equity interest was $15 million and is included in the measurement of consideration transferred. There was no significant impact as a result of remeasuring the carrying value of the Company’s prior equity interest in Anviti held before the business combination.

2020 Acquisitions

On April 6, 2020, the Company completed the acquisition of 100% share capital of Farmington Administrative Services LLC, a U.S.-based national provider of enrollment solutions and voluntary benefits, and certain assets of other Farmington companies.

On January 31, 2020, the Company completed the acquisition of 100% share capital of Cytelligence Inc., a Canadian-based cyber security firm that provides incident response advisory, digital forensic expertise, security consulting services, and cyber security training for employees to help organizations respond to cyber security threats and strengthen their security position.

On January 3, 2020, the Company completed the acquisition of 100% share capital of CoverWallet, Inc., a U.S.-based digital insurance platform for small- and medium-sized businesses.

On January 1, 2020, the Company completed the acquisition of 100% share capital of TRIUM GmbH Insurance Broker, an insurance broker based in Germany.

On January 1, 2020, the Company completed the acquisition of 100% share capital of Assimedia SA, an insurance broker based in Switzerland.

On January 1, 2020, the Company completed the acquisition of 100% share capital of Apollo Conseil et Courtage, an insurance broker based in France.

Completed Dispositions

The Company completed six dispositions during the year ended December 31, 2021, including the sale of Aon’s Retiree Health ExchangeTM business. The Company completed one disposition during the year ended December 31, 2020 and eight dispositions during the year ended December 31, 2019.

The pretax gains recognized related to dispositions were $142 million, $25 million, and $13 million for the years ended December 31, 2021, December 31, 2020 and December 31, 2019, respectively. Gains recognized as a result of a disposition are included in Other income in the Consolidated Statements of Income. The pretax losses recognized in the Consolidated Statements of Income related to these dispositions were insignificant for the years ended December 31, 2021, December 31, 2020 and December 31, 2019, respectively.

Other Significant Activity

On March 9, 2020, Aon and WTW, an Irish public limited company, entered into a business combination agreement (the “Business Combination Agreement”) with respect to a combination of the parties (the “Combination”). On July 26, 2021, Aon and WTW mutually agreed to terminate the Business Combination Agreement, (the “Termination Agreement”). Aon Corporation paid a $1 billion termination fee pursuant to the Termination Agreement. Refer to “Termination of Business Combination Agreement” within Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for further information.

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Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

Goodwill and Other Intangible Assets

The changes in the net carrying amount of goodwill for the years ended December 31, 2021 and 2020, respectively, are as follows (in millions):

Balance as of January 1, 2020	$	8,165
Goodwill related to current year acquisitions	314
Goodwill related to disposals	(3)
Foreign currency translation and other	190
Balance as of December 31, 2020	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434

Other intangible assets by asset class are as follows (in millions):

As of December 31	2021						2020
	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
Customer-related and contract-based	$	2,289	$	1,848	$	441	$	2,337	$	1,775	$	562
Technology and other	407		357		50		435		358		77
Tradenames (1)	14		13		1		14		13		1
Total	$	2,710	$	2,218	$	492	$	2,786	$	2,146	$	640

(1)In 2020, Aon wrote off $1.0 billion of fully amortized tradenames, including the Hewitt and Benfield tradenames. The company no longer expects to receive economic benefits from these tradenames.

Amortization expense and impairment charges from finite lived intangible assets were $147 million, $246 million, and $392 million for the years ended December 31, 2021, 2020, and 2019, respectively.

The estimated future amortization for finite-lived intangible assets as of December 31, 2021 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2022	$	100
2023	89
2024	72
2025	59
2026	37
Thereafter	135
Total	$	492

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Debt

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Debt

Debt

The following is a summary of outstanding debt (in millions):

As of December 31	2021		2020
Commercial paper	$	665	$	—
2.80% Senior Notes due March 2021 (1)	—		400
2.20% Senior Notes due November 2022 (2)	499		498
4.00% Senior Notes due November 2023	349		349
3.50% Senior Notes due June 2024	598		597
3.875% Senior Notes due December 2025	748		747
2.875% Senior Notes due May 2026 (EUR 500M)	563		606
8.205% Junior Subordinated Notes due January 2027	521		521
4.50% Senior Notes due December 2028	347		347
3.75% Senior Notes due May 2029	745		744
2.80% Senior Notes due May 2030	993		992
2.05% Senior Notes due August 2031	396		—
2.60% Senior Notes due December 2031	496		—
6.25% Senior Notes due September 2040	296		296
4.25% Senior Notes due December 2042	201		200
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	544		544
4.75% Senior Notes due May 2045	593		593
2.90% Senior Notes due August 2051	591		—
Other	—		48
Total debt	9,392		7,729
Less: Short-term debt and current portion of long-term debt	1,164		448
Total long-term debt	$	8,228	$	7,281

(1)The 2.80% Senior Notes due March 2021 were repaid in full on February 16, 2021.

(2)The 2.20% Senior Notes due November 2021 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2021.

Notes

On December 2, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company incorporated under the laws of England and Wales, both wholly owned subsidiaries of the company, co-issued $500 million aggregate principal amount of 2.60% Senior Notes set to mature on December 2, 2031. The Company intends to use the net proceeds of the offering for general corporate purposes.

On August 23, 2021, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales, both wholly owned subsidiaries of the Company, co-issued $400 million 2.05% Senior Notes due August 2031 and $600 million of 2.90% Senior Notes due August 2051. The Company intends to use the net proceeds of the offering for general corporate purposes.

On January 13, 2021, Aon Global Limited, a limited company organized under the laws of England and Wales and a wholly owned subsidiary of Aon plc, issued an irrevocable notice of redemption to holders of its 2.80% Senior Notes for the redemption of all $400 million outstanding aggregate principal amount of the notes, which were set to mature in March 2021 and classified as Short-term debt and current portion of long-term debt as of December 31, 2020. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

On May 29, 2020, Aon Corporation, a Delaware corporation and a wholly owned subsidiary of Aon Corporation, issued an irrevocable notice of redemption to holders of its 5.00% Senior Notes, which were set to mature on September 30, 2020, for the redemption of all $600 million outstanding aggregate principal amount of the notes. The redemption date was on June 30, 2020 and resulted in a loss of $7 million due to extinguishment.

On May 12, 2020, Aon Corporation issued $1 billion 2.80% Senior Notes due May 2030. Aon Corporation used a portion of the net proceeds on June 30, 2020 to repay its outstanding 5.00% Senior Notes, which were set to mature on September 30, 2020. The Company used the remainder to repay other borrowings and for general corporate purposes.

Each of the notes issued by Aon Corporation is fully and unconditionally guaranteed by Aon Global Limited, Aon plc, and Aon Global Holding plc. Each of the notes issued by Aon Global Limited is fully and unconditionally guaranteed by Aon plc, Aon Global Holdings plc, and Aon Corporation. All guarantees of Aon plc and Aon Global Limited of the Co-Issued Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the Co-Issuers. Refer to “Guarantee of Registered Securities” within Part II Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for further information regarding guarantees of outstanding debt securities. Each of the notes described and identified in the table above contains customary representations, warranties, and covenants, and the Company was in compliance with all such covenants as of December 31, 2021.

Repayments of total debt as of December 31, 2021 are as follows (in millions):

2022	$	1,165
2023	350
2024	600
2025	750
2026	566
Thereafter	6,077
Total Repayments	9,508
Unamortized discounts, premiums, and debt issuance costs	(116)
Total Debt	$	9,392

Revolving Credit Facilities

As of December 31, 2021, Aon plc had two primary committed credit facilities outstanding: its $1.0 billion multi-currency U.S. credit facility expiring in September 2026 and its $750 million multi-currency U.S. credit facility expiring in October 2023. In aggregate, these two facilities provide $1.75 billion in available credit. The $1.0 billion credit facility was entered into on September 28, 2021 and replaced the $900 million credit facility, which was scheduled to mature on February 2, 2022.

Each of these primary committed credit facilities includes customary representations, warranties, and covenants, including financial covenants that require Aon to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, in each case, tested quarterly. At December 31, 2021, Aon did not have borrowings under either of these primary committed credit facilities, and was in compliance with the financial covenants and all other covenants contained therein during the rolling year ended December 31, 2021.

Commercial Paper

Aon Corporation has established a U.S. commercial paper program (the “U.S. Program”) and Aon Global Holdings plc has established a European multi-currency commercial paper program (the “European Program” and, together with the U.S. Program, the “Commercial Paper Programs”). Commercial paper may be issued in aggregate principal amounts of up to

$1 billion under the U.S. Program and €625 million under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was $1.75 billion at December 31, 2021. The aggregate capacity of the U.S. Program was increased in the fourth quarter of 2021 from $900 million to $1 billion. The aggregate capacity of the Commercial Paper Program remains fully backed by the Company’s committed credit facilities. The U.S. Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, and Aon Global Holdings plc and the European Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, and Aon Corporation.

Approximately $400 million of the Termination Fee (as defined in Part II, Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations) was paid on July 27, 2021 using proceeds of commercial paper issued by Aon Corporation under the U.S. Program, where the aggregate principal was raised on July 26, 2021.

Commercial paper outstanding, which is included in Short-term debt and current portion of long-term debt in the Company’s Consolidated Statements of Financial Position, is as follows (in millions):

As of December 31	2021		2020
Commercial paper outstanding	$	665	$	—

The weighted average commercial paper outstanding and its related interest rates are as follows (in millions, except percentages):

	Years Ended December 31
	2021			2020
Weighted average commercial paper outstanding	$	273		$	343
Weighted average interest rate of commercial paper outstanding	0.01		%	1.47		%

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Lease Commitments

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Lease Commitments

Lease Commitments

The classification of operating and finance lease asset and liability balances within the Consolidated Statements of Financial Position are as follows (in millions):

As of December 31		2021		2020
Assets
Operating lease assets	Operating lease right-of-use assets	$	786	$	911
Finance lease assets	Other non-current assets	63		89
Total lease assets		$	849	$	1,000
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	194	$	204
Finance	Other current liabilities	19		30
Non-current lease liabilities
Operating	Non-current operating lease liabilities	772		897
Finance	Other non-current liabilities	46		65
Total lease liabilities		$	1,031	$	1,196

The components of lease costs are as follows (in millions):

	Years Ended December 31
	2021		2020
Operating lease cost	$	217	$	221
Finance lease costs
Amortization of leased assets	26		25
Interest on lease liabilities	1		3
Variable lease cost	49		48
Short-term lease cost (1)	11		10
Sublease income	(31)		(32)
Net lease cost	$	273	$	275

(1) Short-term lease cost does not include expenses related to leases with a lease term of one month or less.

Weighted average remaining lease term and discount rate related to operating and finance leases are as follows:

As of December 31	2021		2020
Weighted average remaining lease term (years)
Operating leases	6.9		7.4
Finance leases	3.6		4.2
Weighted average discount rate
Operating leases	2.8	%	2.9	%
Finance leases	1.0	%	1.0	%

Other cash and non-cash related activities are as follows (in millions):

	Years Ended December 31
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	244	$	236
Financing cash flows for finance leases	$	23	$	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	44	$	146
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	13
Operating lease ROU asset expense (1)	$	142	$	178
Changes in Non-current operating lease liabilities (1)	$	(125)	$	(47)

(1)The Company has recorded non-cash changes in Operating lease ROU assets and Non-current operating lease liabilities through Other assets and liabilities in Cash flows from operations within the Consolidated Statements of Cash Flows.

Maturity analysis of operating and finance leases as of December 31, 2021 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2022	$	207	$	26	$	233
2023	175		20		195
2024	144		18		162
2025	121		10		131
2026	110		—		110
Thereafter	299		—		299
Total undiscounted future minimum lease payments	1,056		74		1,130
Less: Imputed interest	(90)		(9)		(99)
Present value of lease liabilities	$	966	$	65	$	1,031

Lease Commitments

Lease Commitments

The classification of operating and finance lease asset and liability balances within the Consolidated Statements of Financial Position are as follows (in millions):

As of December 31		2021		2020
Assets
Operating lease assets	Operating lease right-of-use assets	$	786	$	911
Finance lease assets	Other non-current assets	63		89
Total lease assets		$	849	$	1,000
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	194	$	204
Finance	Other current liabilities	19		30
Non-current lease liabilities
Operating	Non-current operating lease liabilities	772		897
Finance	Other non-current liabilities	46		65
Total lease liabilities		$	1,031	$	1,196

The components of lease costs are as follows (in millions):

	Years Ended December 31
	2021		2020
Operating lease cost	$	217	$	221
Finance lease costs
Amortization of leased assets	26		25
Interest on lease liabilities	1		3
Variable lease cost	49		48
Short-term lease cost (1)	11		10
Sublease income	(31)		(32)
Net lease cost	$	273	$	275

(1) Short-term lease cost does not include expenses related to leases with a lease term of one month or less.

Weighted average remaining lease term and discount rate related to operating and finance leases are as follows:

As of December 31	2021		2020
Weighted average remaining lease term (years)
Operating leases	6.9		7.4
Finance leases	3.6		4.2
Weighted average discount rate
Operating leases	2.8	%	2.9	%
Finance leases	1.0	%	1.0	%

Other cash and non-cash related activities are as follows (in millions):

	Years Ended December 31
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	244	$	236
Financing cash flows for finance leases	$	23	$	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	44	$	146
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	13
Operating lease ROU asset expense (1)	$	142	$	178
Changes in Non-current operating lease liabilities (1)	$	(125)	$	(47)

(1)The Company has recorded non-cash changes in Operating lease ROU assets and Non-current operating lease liabilities through Other assets and liabilities in Cash flows from operations within the Consolidated Statements of Cash Flows.

Maturity analysis of operating and finance leases as of December 31, 2021 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2022	$	207	$	26	$	233
2023	175		20		195
2024	144		18		162
2025	121		10		131
2026	110		—		110
Thereafter	299		—		299
Total undiscounted future minimum lease payments	1,056		74		1,130
Less: Imputed interest	(90)		(9)		(99)
Present value of lease liabilities	$	966	$	65	$	1,031

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Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

Income before income tax and the provision for income tax consist of the following (in millions):

	Years Ended December 31
	2021		2020		2019
Income (loss) before income taxes:
Ireland	$	15	$	(86)	$	200
U.K.	549		634		228
U.S.	(818)		(28)		(220)
Other	2,185		1,946		1,662
Total	$	1,931	$	2,466	$	1,870
Income tax expense:
Current:
Ireland	$	2	$	2	$	1
U.K.	50		30		20
U.S. federal	197		126		22
U.S. state and local	72		22		41
Other	291		259		249
Total current tax expense	$	612	$	439	$	333
Deferred tax expense (benefit):
Ireland	$	(1)	$	(1)	$	(1)
U.K.	131		39		35
U.S. federal	(83)		(72)		(20)
U.S. state and local	(30)		(4)		(27)
Other	(6)		47		(23)
Total deferred tax expense (benefit)	$	11	$	9	$	(36)
Total income tax expense	$	623	$	448	$	297

Income before income taxes shown above is based on the location of the business unit to which such earnings are attributable for tax purposes. In addition, because the earnings shown above may, in some cases, be subject to taxation in more than one country, the income tax provision shown above as Ireland, U.K., U.S. or Other may not correspond to the geographic attribution of the earnings.

The Company performs a reconciliation of the income tax provisions based on its domicile and statutory rate at each reporting period. Due to the Reorganization, the 2021 and 2020 reconciliations are based on the Irish statutory corporate tax rate of 25.0%, while the 2019 reconciliation is based on the U.K. statutory corporate tax rate of 19.0%. The reconciliation to the provisions reflected in the Consolidated Financial Statements is as follows:

	Years Ended December 31
	2021	2020	2019
Statutory tax rate	25.0%	25.0%	19.0%
U.S. state income taxes, net of U.S. federal benefit	1.5	1.0	0.5
Taxes on international operations (1) (4)	(15.4)	(9.8)	(6.0)
Nondeductible expenses	3.3	2.1	1.6
Adjustments to prior year tax requirements	(0.2)	—	0.1
Deferred tax adjustments, including statutory rate changes	3.2	0.7	—
Deferred tax adjustments, international earnings	1.8	0.7	—
Adjustments to valuation allowances	(0.2)	—	1.8
Change in uncertain tax positions	2.1	1.5	2.2
Excess tax benefits related to shared based compensation (2)	(2.4)	(2.2)	(2.8)
U.S. Tax Reform impact (3)	—	—	(0.3)
Capital Losses	—	(1.8)	—
Non-deductible transaction costs	1.1	1.3	—
Non-deductible termination fee	12.9	—	—
Other — net	(0.4)	(0.3)	(0.2)
Effective tax rate	32.3%	18.2%	15.9%

(1)The Company determines the adjustment for taxes on international operations based on the difference between the statutory tax rate applicable to earnings in each foreign jurisdiction and the enacted rate of 25.0%, 25.0% and 19.0% at December 31, 2021, 2020, and 2019, respectively. The benefit to the Company’s effective income tax rate from taxes on international operations relates to benefits from lower-taxed global operations, primarily due to the use of global funding structures and the tax holiday in Singapore.

(2)Excess tax benefits and deficiencies from share-based payment transactions are recognized as income tax expense or benefit in the Company’s Consolidated Statements of Income.

(3)The impact of the Tax Cuts and Jobs Act including adjustments to the Transition Tax.

(4)In July 2020, final U.S. tax regulations were issued regarding the GILTI high tax election, allowing taxpayers to exclude from GILTI the income of a Controlled Foreign Corporation that incurs a foreign tax rate more than 90% of the top U.S. corporate tax rate. A GILTI high tax election may be made on an annual basis, and taxpayers may choose to apply the election to taxable years beginning after December 31, 2017. The Company expects to make the GILTI high-tax election for 2021 and therefore recorded the impact of making the election.

The Company has elected to account for GILTI in the period in which it is incurred, and therefore has not provided deferred tax impacts of GILTI in its Consolidated Financial Statements.

The components of the Company’s deferred tax assets and liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	581	$	653
Lease liabilities	207		248
Employee benefit plans	160		312
Other accrued expenses	132		103
Accrued interest	97		—
Federal and state benefit of interest from uncertain tax positions (1)	45		37
Deferred revenue	36		36
Investment basis differences	25		28
Lease and service guarantees	1		2
Other	25		17
Total	1,309		1,436
Valuation allowance on deferred tax assets	(230)		(205)
Total	$	1,079	$	1,231
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(243)	$	(291)
Lease right-of-use asset	(173)		(211)
Deferred costs	(159)		(141)
Unremitted earnings	(58)		(37)
Other accrued expenses	(27)		(22)
Unrealized foreign exchange gains	(22)		(26)
Other	(32)		(41)
Total	$	(714)	$	(769)
Net deferred tax asset	$	365	$	462

(1)The $37 million of Federal and state benefit of interest from uncertain tax positions as of December 31, 2020 was previously classified as Other.

Deferred income taxes (assets and liabilities have been netted by jurisdiction) have been classified in the Consolidated Statements of Financial Position as follows (in millions):

As of December 31	2021		2020
Deferred tax assets — non-current	766		724
Deferred tax liabilities — non-current	(401)		(262)
Net deferred tax asset	$	365	$	462

In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized and adjusts the valuation allowance accordingly. Considerations with respect to the realizability of deferred tax assets include the period of expiration of the deferred tax asset, historical earnings and projected future taxable income by jurisdiction as well as tax liabilities for the tax jurisdiction to which the tax asset relates. Significant management judgment is required in determining the assumptions and estimates related to the amount and timing of future taxable income. Valuation allowances have been established primarily with regard to the tax benefits of certain net operating loss, capital loss, and interest carryforwards. Valuation allowances increased by $25 million as of December 31, 2021, when compared to December 31, 2020. The change is primarily attributable to the increase in the UK tax rate offset by the release of valuation allowances related to certain net operating and capital loss carryforwards.

The Company generally intends to limit distributions from foreign subsidiaries in excess of U.S. tax earnings and profits (except where distributions would be limited by available cash) and to limit repatriations from certain other jurisdictions that would otherwise generate a U.S. tax liability. As of December 31, 2021, the Company has accrued $58 million for local country income taxes, withholding taxes and state income taxes on those undistributed earnings that are not indefinitely reinvested. The Company has not provided for deferred taxes on outside basis differences in our investments in our foreign subsidiaries that are unrelated to these accumulated undistributed earnings, as these outside basis differences are indefinitely reinvested. A determination of the unrecognized deferred taxes related to these other components of our outside basis differences is not practicable.

The Company had the following carryforwards (in millions):

As of December 31	2021		2020
U.K.
Operating loss carryforwards	$	41	$	266
Capital loss carryforwards	$	573	$	577
Interest carryforwards	$	—	$	121
U.S.
Federal operating loss carryforwards	$	25	$	49
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	1,140	$	1,220
State operating loss carryforwards	$	398	$	378
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	551	$	573
Other Non-U.S.
Operating loss carryforwards	$	301	$	400
Capital loss carryforwards	$	35	$	42
Interest carryforwards	$	26	$	34
Other carryforwards	$	5	$	—

The U.K. operating losses, capital losses, and interest carryforward each have an indefinite carryforward period. The federal operating loss carryforwards generated through December 31, 2017 expire at various dates between 2034 and 2036 while federal operating loss carryforwards generated after this date have indefinite carryforward periods. State net operating losses as of December 31, 2021 have various carryforward periods and will begin to expire in 2022. Federal and state capital losses can be carried forward until 2023. Federal and state interest carryforwards have indefinite carryforward periods. Operating, capital losses, and other carryforwards in other non-U.S. jurisdictions have various carryforward periods and will begin to expire in 2022. The interest carryforwards in other non-U.S. jurisdictions have an indefinite carryforward period.

During 2012, the Company was granted a tax holiday for the period from October 1, 2012 through September 30, 2022, with respect to withholding taxes and certain income derived from services in Singapore. This tax holiday and reduced withholding tax rate may be extended when certain conditions are met or may be terminated early if certain conditions are not met. The benefit realized was approximately $104 million, $97 million, and $90 million during the years ended December 31, 2021, 2020, and 2019, respectively. The impact of this tax holiday on diluted earnings per share was $0.46, $0.42, and $0.37 during the years ended December 31, 2021, 2020, and 2019, respectively.

Uncertain Tax Positions

The following is a reconciliation of the Company’s beginning and ending amount of uncertain tax positions (in millions):

	2021		2020
Balance at January 1	$	321	$	299
Additions based on tax positions related to the current year	33		25
Additions for tax positions of prior years	7		7
Reductions for tax positions of prior years	(4)		(3)
Settlements	—		—
Business combinations	—		—
Lapse of statute of limitations	(10)		(7)
Foreign currency translation	—		—
Balance at December 31	$	347	$	321

The Company’s liability for uncertain tax positions as of December 31, 2021, 2020, and 2019, includes $295 million, $270 million, and $248 million, respectively, related to amounts that would impact the effective tax rate if recognized. It is possible that the amount of unrecognized tax benefits may change in the next twelve months; however, the Company does not expect the change to have a significant impact on its consolidated statements of income or consolidated balance sheets. These changes may be the result of settlements of ongoing audits. At this time, an estimate of the range of the reasonably possible outcomes within the next twelve months cannot be made.

The Company recognizes interest and penalties related to uncertain tax positions in its provision for income taxes. The Company accrued potential interest and penalties of $22 million, $21 million, and $24 million in 2021, 2020, and 2019, respectively. The Company recorded a liability for interest and penalties of $142 million, $120 million, and $99 million as of December 31, 2021, 2020, and 2019, respectively.

The Company and its subsidiaries file income tax returns in their respective jurisdictions. The Company has substantially concluded all U.S. federal income tax matters for years through 2007. Material U.S. state and local income tax jurisdiction examinations have been concluded for years through 2012. The Company has concluded income tax examinations in its primary non-U.S. jurisdictions through 2008.

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Shareholders' Equity

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Shareholders' Equity

Shareholders’ Equity

Distributable Profits

The Company is required under Irish law to have available “distributable profits” to make share repurchases or pay dividends to shareholders. Distributable profits are created through the earnings of the Irish parent company and, among other methods, through intercompany dividends or a reduction in share capital approved by the High Court of Ireland. Distributable profits are not linked to a U.S. GAAP reported amount (e.g., retained earnings). On July 26, 2021, we received approval from the High Court of Ireland to complete a reduction in share premium to create distributable profits of $34.0 billion to support the payment of possible future dividends or future share repurchases, if and to the extent declared by the directors in compliance with their duties under Irish law. As of December 31, 2021 and 2020, the Company had distributable profits in excess of $32.7 billion and $0.2 billion, respectively. We believe that we have the ability to create sufficient distributable profits for the foreseeable future.

Ordinary Shares

Aon has a share repurchase program authorized by the Company’s Board of Directors. The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in authorized repurchases in February 2022 for a total of $27.5 billion in repurchase authorizations.

Under the Repurchase Program, the Company’s class A ordinary shares may be repurchased through the open market or in privately negotiated transactions, from time to time, based on prevailing market conditions and will be funded from available capital.

The following table summarizes the Company’s share repurchase activity (in millions, except per share data):

	Years Ended December 31
	2021		2020
Shares repurchased	12.4		8.5
Average price per share	$	286.82	$	206.28
Costs recorded to retained earnings
Total repurchase cost	$	3,543	$	1,761
Additional associated costs	—		2
Total costs recorded to retained earnings	$	3,543	$	1,763

At December 31, 2021, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $1.7 billion. Under the Repurchase Program, the Company has repurchased a total of 149.6 million shares for an aggregate cost of approximately $18.3 billion.

Weighted Average Ordinary Shares

Weighted average ordinary shares outstanding are as follows (in millions):

	Years Ended December 31
	2021	2020	2019
Basic weighted average ordinary shares outstanding	224.7	231.9	238.6
Dilutive effect of potentially issuable shares	1.4	1.2	2.0
Diluted weighted average ordinary shares outstanding	226.1	233.1	240.6

Potentially issuable shares are not included in the computation of Diluted net income per share attributable to Aon shareholders if their inclusion would be antidilutive. There were 0.3 million shares excluded from the calculation in 2021 and no shares excluded from the calculation in 2020 and 2019.

Accumulated Other Comprehensive Loss

Changes in Accumulated other comprehensive loss by component, net of related tax, are as follows (in millions):

	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2018	(15)		(1,319)		(2,575)		(3,909)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	(10)		15		(287)		(282)
Tax benefit (expense)	1		(1)		58		58
Other comprehensive income (loss) before reclassifications, net	(9)		14		(229)		(224)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	14		—		109		123
Tax expense	(2)		—		(21)		(23)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		88		100
Net current period other comprehensive income (loss)	3		14		(141)		(124)
Balance at December 31, 2019	(12)		(1,305)		(2,716)		(4,033)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	1		258		(255)		4
Tax benefit	—		2		60		62
Other comprehensive income (loss) before reclassifications, net	1		260		(195)		66
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	15		—		125		140
Tax expense	(3)		—		(31)		(34)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		94		106
Net current period other comprehensive income (loss)	13		260		(101)		172
Balance at December 31, 2020	$	1	$	(1,045)	$	(2,817)	$	(3,861)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	—		(290)		227		(63)
Tax benefit (expense)	—		2		(58)		(56)
Other comprehensive income (loss) before reclassifications, net	—		(288)		169		(119)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	2		—		142		144
Tax expense	(1)		—		(34)		(35)
Amounts reclassified from accumulated other comprehensive income, net (3)	1		—		108		109
Net current period other comprehensive income (loss)	1		(288)		277		(10)
Balance at December 31, 2021	$	2	$	(1,333)	$	(2,540)	$	(3,871)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Consolidated Statements of Income. Refer to Note 13 “Derivatives and Hedging” for further information regarding the Company’s derivative and hedging activity.

(2)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Other income (expense) in the Consolidated Statements of Income.

(3)It is the Company’s policy to release income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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Employee Benefits

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Employee Benefits

Employee Benefits

Defined Contribution Savings Plans

Aon maintains defined contribution savings plans for the benefit of its employees. The expense recognized for these plans is included in Compensation and benefits in the Consolidated Statements of Income. The expense for the significant plans in the U.S., U.K., Netherlands, and Canada is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	103	$	87	$	98
U.K.	46		42		41
Netherlands and Canada	35		26		25
Total	$	184	$	155	$	164

Pension and Other Postretirement Benefits

The Company sponsors defined benefit pension and postretirement health and welfare plans that provide retirement, medical, and life insurance benefits. The postretirement health care plans are contributory, with retiree contributions adjusted annually, and the life insurance and pension plans are generally noncontributory. The significant U.S., U.K., Netherlands, and Canada pension plans are closed to new entrants.

Pension Plans

The following tables provide a reconciliation of the changes in the projected benefit obligations and fair value of assets for the years ended December 31, 2021 and 2020, and a statement of the funded status as of December 31, 2021 and 2020, for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. These plans represent approximately 90% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2021		2020		2021		2020		2021		2020
Change in projected benefit obligation
At January 1	$	5,406	$	4,779	$	3,380	$	3,192	$	1,625	$	1,425
Service cost	1		—		—		—		—		—
Interest cost	65		88		57		85		12		19
Plan amendment	—		3		—		—		—		—
Settlements	(14)		(7)		—		—		—		—
Actuarial (gain) loss	(292)		520		(103)		274		24		112
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(58)		232		—		—		(83)		113
As of December 31	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Accumulated benefit obligation at end of year	$	4,919	$	5,406	$	3,164	$	3,380	$	1,504	$	1,592
Change in fair value of plan assets
At January 1	$	6,652	$	5,959	$	2,276	$	2,066	$	1,497	$	1,303
Actual return on plan assets	(136)		618		211		289		46		109
Employer contributions	9		8		61		92		17		20
Settlements	(14)		(7)		—		—		—		—
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(76)		283		—		—		(83)		109
As of December 31	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Market related value at end of year	$	6,246	$	6,652	$	2,174	$	2,076	$	1,430	$	1,497
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	1,327	$	1,246	$	(786)	$	(1,104)	$	(101)	$	(128)
Unrecognized prior-service cost	40		43		—		—		(6)		(7)
Unrecognized loss	1,215		1,286		1,551		1,812		489		521
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

Net actuarial gains decreased the benefit obligation in 2021 primarily due to the increase in the discount rates. During 2020, the net actuarial losses increased the benefit obligation primarily due to the decrease in discount rates.

In November 2020, the Company entered into an insurance contract that covers a portion of the assets within a select U.K. pension scheme. The transaction resulted in a decrease in Prepaid pension assets and Accumulated other comprehensive income of $94 million.

Amounts recognized in the Consolidated Statements of Financial Position consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Prepaid benefit cost (1)	$	1,344	$	1,268	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(52)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(16)		(21)		(734)		(1,052)		(96)		(123)
Accumulated other comprehensive loss	1,255		1,329		1,551		1,812		483		514
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

(1)Included in Prepaid pension.

(2)Included in Other current liabilities.

(3)Included in Pension, other postretirement, and postemployment liabilities.

Amounts recognized in Accumulated other comprehensive loss (income) that have not yet been recognized as components of net periodic benefit cost at December 31, 2021 and 2020 consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Net loss	$	1,215	$	1,286	$	1,551	$	1,812	$	489	$	521
Prior service cost (income)	40		43		—		—		(6)		(7)
Total	$	1,255	$	1,329	$	1,551	$	1,812	$	483	$	514

In 2021, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $3.2 billion, an ABO of $3.2 billion, and plan assets with a fair value of $2.4 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $17 million, an ABO of $17 million and no plan assets. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.5 billion and plan assets with a fair value of $1.4 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $409 million and plan assets with a fair value of $326 million.

In 2020, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $3.3 billion, an ABO of $3.3 billion, and plan assets with a fair value of $2.2 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $54 million, an ABO of $54 million and plan assets with a fair value of $32 million. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.6 billion and plan assets with a fair value of $1.4 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $443 million and plan assets with a fair value of $342 million.

Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	U.K.						U.S.						Other
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Service cost	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	65		88		109		57		85		108		12		19		27
Expected return on plan assets, net of administration expenses	(137)		(159)		(191)		(130)		(134)		(136)		(32)		(34)		(40)
Amortization of prior-service cost	2		2		1		—		1		2		—		—		—
Amortization of net actuarial loss	32		30		29		78		68		53		15		12		12
Net periodic benefit (income) cost	(37)		(39)		(52)		5		20		27		(5)		(3)		(1)
Settlement expense	5		2		5		—		—		—		—		—		—
Total net periodic benefit cost (income)	$	(32)	$	(37)	$	(47)	$	5	$	20	$	27	$	(5)	$	(3)	$	(1)

The Company uses a full-yield curve approach in the estimation of the service and interest cost components of net periodic pension and postretirement benefit cost for its major pension and other postretirement benefit plans. This estimation was obtained by applying the specific spot rates along the yield curve used in the determination of the benefit obligation to the relevant projected cash flows.

Transfer payments from certain U.K. pension plans exceeded the plan’s service and interest cost in 2021, 2020, and 2019. This triggered settlement accounting which required immediate recognition of a portion of the accumulated losses associated with the plan. Consequently, the Company recognized a non-cash settlement charge for approximately £3 million in 2021 ($5 million using December 31, 2021 exchange rates), approximately £2 million in 2020 ($2 million using December 31, 2020 exchange rates), and approximately £4 million in 2019 ($5 million using December 31, 2019 exchange rates).

The weighted-average assumptions used to determine benefit obligations are as follows:

	U.K.		U.S. (1)		Other
	2021	2020	2021	2020	2021	2020
Discount rate	1.96%	1.45%	2.23 - 2.80%	1.74 - 2.45%	1.00 - 2.97%	0.38 - 2.47%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.52%	2.12%	N/A	N/A	2.00%	2.00%

(1)U.S. pension plans are frozen and therefore not impacted by compensation increases or price inflation.

The weighted-average assumptions used to determine the net periodic benefit cost are as follows:

	U.K.			U.S.			Other
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Discount rate	1.20%	1.89%	2.95%	1.12 - 1.79%	2.36 - 2.76%	3.92 - 4.26%	0.28 - 2.00%	0.74 - 2.90%	1.89 - 3.88%
Expected return on plan assets, net of administration expenses	2.04%	2.74%	3.64%	2.65 - 6.56%	3.30- 7.04%	7.05%	1.70 - 2.65%	2.10 - 3.10%	2.50 - 4.10%
Rate of compensation increase	3.22 - 3.72%	3.24 - 3.74%	3.73 - 4.23%	N/A	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%	1.00 - 3.00%

Expected Return on Plan Assets

To determine the expected long-term rate of return on plan assets, the historical performance, investment community forecasts, and current market conditions are analyzed to develop expected returns for each asset class used by the plans. The expected returns for each asset class are weighted by the target allocations of the plans. The expected return of 6.56% on U.S. plan assets reflects a portfolio that is seeking asset growth through a higher equity allocation while maintaining prudent risk levels. The portfolio contains certain assets that have historically resulted in higher returns, as well as other financial instruments to minimize downside risk.

No plan assets are expected to be returned to the Company during 2022.

Fair value of plan assets

The Company determined the fair value of plan assets through numerous procedures based on the asset class and available information. Refer to Note 14 “Fair Value Measurements and Financial Instruments” for a description of the procedures performed to determine the fair value of the plan assets.

The fair values of the Company’s U.S. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	93	$	93	$	—	$	—
Equity investments:
Equity securities	86		86		—		—
Equity derivatives	19		—		19		—
Pooled funds (2)	548		—		—		—
Fixed income investments:
Corporate bonds	249		—		249		—
Government and agency bonds	230		192		38		—
Pooled funds (2)	838		—		—		—
Other investments:
Real estate (2) (3)	156		—		—		—
Alternative investments (2) (4)	159		—		—		—
Total	$	2,378	$	371	$	306	$	—

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	79	$	79	$	—	$	—
Equity investments:
Equity securities	207		207		—		—
Equity derivatives	62		—		62		—
Pooled funds (2)	640		90		—		—
Fixed income investments:
Corporate bonds	167		—		167		—
Government and agency bonds	233		200		33		—
Pooled funds (2)	543		212		—		—
Other investments:
Real estate (2)(3)	163		—		—		—
Alternative investments (2) (4)	182		—		—		—
Total	$	2,276	$	788	$	262	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of property funds and trusts holding direct real estate investments.

(4)Consists of limited partnerships, private equity, and hedge funds.

The fair values of the Company’s major U.K. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	872	$	872	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(1,640)		—		(1,640)		—
Government and agency bonds	2,969		2,969		—		—
Annuities	2,305		—		—		2,305
Pooled funds (2)	463		—		—		—
Other investments:
Real estate (2) (4)	130		—		—		—
Pooled funds (2) (5)	1,147		—		—		—
Total	$	6,246	$	3,841	$	(1,640)	$	2,305

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	182	$	182	$	—	$	—
Equity investments:
Pooled funds (2)	4		—		—		—
Fixed income investments:
Derivatives (3)	(1,424)		—		(1,424)		—
Corporate bonds	4		4		—		—
Government and agency bonds	2,872		2,872		—		—
Annuities	2,625		—		—		2,625
Pooled funds (2)	875		—		—		—
Other investments:
Real estate (2) (4)	117		—		—		—
Pooled funds (2) (5)	1,397		4		—		—
Total	$	6,652	$	3,062	$	(1,424)	$	2,625

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of equity securities and equity derivatives, including repurchase agreements.

(4)Consists of property funds and trusts holding direct real estate investments.

(5)Consists of multi-strategy limited partnerships, private equity, hedge funds, and collective investment schemes with a diversified portfolio of cash, equities, equity related securities, derivatives, and/or fixed income securities.

The following table presents the changes in the Level 3 fair-value category in the Company’s U.K. pension plans for the years ended December 31, 2021 and December 31, 2020 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2020	$	1,849
Actual return on plan assets:
Relating to assets still held at December 31, 2020	13
Purchase, sales and settlements-net	682
Foreign exchange	81
Balance at December 31, 2020	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchases, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	$	2,305

The fair values of the Company’s other major pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	29	$	29	$	—	$	—
Equity investments:
Equity securities	72		72		—		—
Pooled funds (2)	316		—		—		—
Fixed income investments:
Government and agency bonds	350		350		—		—
Pooled funds (2)	597		—		—		—
Other investments:
Alternative investments (2) (3)	55		—		—		—
Real estate (2) (4)	11		—		—		—
Total	$	1,430	$	451	$	—	$	—

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	37	$	37	$	—	$	—
Equity investments:
Equity securities	75		75		—		—
Pooled funds (2)	290		—		—		—
Fixed income investments:
Government and agency bonds	395		395		—		—
Pooled funds (2)	627		—		—		—
Other investments:
Alternative investments (2) (3)	63		—		—		—
Real estate (2) (4)	10		—		—		—
Total	$	1,497	$	507	$	—	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of limited partnerships, private equity, and hedge funds.

(4)Consists of property funds and trusts holding direct real estate investments.

Investment Policy and Strategy

The U.S. investment policy, as established by the RPGIC, seeks reasonable asset growth at prudent risk levels within weighted average target allocations. At December 31, 2021, the weighted average targeted allocation for the U.S. plans was 31% for equity investments, 54% for fixed income investments, and 15% for other investments. Aon believes that plan assets are well-diversified and are of appropriate quality. The investment portfolio asset allocation is reviewed quarterly and re-balanced to be within policy target allocations. The investment policy is reviewed at least annually and revised, as deemed appropriate by the RPGIC. The investment policies for international plans are generally established by the local pension plan trustees and seek to maintain the plans’ ability to meet liabilities and to comply with local minimum funding requirements. Plan assets are invested in diversified portfolios that provide adequate levels of return at an acceptable level of risk. The investment policies are reviewed at least annually and revised, as deemed appropriate to ensure that the objectives are being met. At December 31, 2021, the weighted average targeted allocation for the U.K. and non-U.S. plans was 6% for equity investments, 88% for fixed income investments, and 6% for other investments.

Cash Flows

Contributions

Based on current assumptions, in 2022, the Company expects to contribute approximately $7 million, $52 million, and $15 million to its significant U.K., U.S., and other major pension plans, respectively.

Estimated Future Benefit Payments

Estimated future benefit payments for plans, not including voluntary one-time lump sum payments, are as follows at December 31, 2021 (in millions):

	U.K.		U.S.		Other
2022	$	164	$	193	$	47
2023	$	171	$	191	$	48
2024	$	177	$	193	$	49
2025	$	183	$	193	$	50
2026	$	188	$	183	$	52
2027 - 2031	$	1,017	$	882	$	275

U.S. and Canadian Other Postretirement Benefits

The following table provides an overview of the accumulated PBO, fair value of plan assets, funded status and net amount recognized as of December 31, 2021 and 2020 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2021		2020
Accumulated projected benefit obligation	$	109	$	117
Fair value of plan assets	17		17
Funded status	(92)		(100)
Unrecognized prior-service credit	(1)		(1)
Unrecognized loss	2		13
Net amount recognized	$	(91)	$	(88)

Other information related to the Company’s other postretirement benefit plans are as follows:

	2021	2020	2019
Net periodic benefit cost recognized (millions)	$5	$4	$3
Weighted-average discount rate used to determine future benefit obligations	2.52 - 3.06%	2.10 - 2.58%	2.93 - 3.25%
Weighted-average discount rate used to determine net periodic benefit costs	1.45 - 2.68%	2.93 - 3.25%	3.91 - 4.26%

Based on current assumptions, the Company expects:

•The amount in Accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost during 2022 is $0.9 million net gain and $0.2 million of prior-service credit.

•To contribute $5 million to fund significant other postretirement benefit plans during 2022.

•Estimated future benefit payments will be approximately $5 million each year for 2022 through 2026, and $25 million in aggregate for 2027-2031.

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Share-Based Compensation Plans

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Share-Based Compensation Plans

Share-Based Compensation Plans

The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):

	Years Ended December 31
	2021		2020		2019
Restricted share units	$	204	$	186	$	198
Performance share awards	189		116		110
Employee share purchase plans and other (1)	56		10		9
Total share-based compensation expense	449		312		317
Tax benefit	87		61		66
Share-based compensation expense, net of tax	$	362	$	251	$	251

(1) Includes expenses related to the Aon United Growth Ownership Plan.

Restricted Share Units

RSUs generally vest between three and five years. The fair value of RSUs is based upon the market value of the Company’s class A ordinary shares at the date of grant. With certain limited exceptions, any break in continuous employment will cause the forfeiture of all non-vested awards. Compensation expense associated with RSUs is recognized on a straight-line basis over the requisite service period. Dividend equivalents are paid on certain RSUs, based on the initial grant amount.

The following table summarizes the status of the Company’s RSUs (shares in thousands, except fair value):

	Years Ended December 31
	2021			2020			2019
	Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)
Non-vested at beginning of year	3,309	$	163	3,634	$	143	4,208	$	120
Granted	1,257	$	253	1,329	$	185	1,306	$	175
Vested	(1,248)	$	151	(1,426)	$	133	(1,661)	$	113
Forfeited	(243)	$	184	(228)	$	157	(219)	$	131
Non-vested at end of year	3,075	$	203	3,309	$	163	3,634	$	143

(1)Represents per share weighted average fair value of award at date of grant.

The fair value of RSUs that vested during 2021, 2020 and 2019 was $189 million, $190 million, and $187 million, respectively.

Unamortized deferred compensation expense amounted to $447 million as of December 31, 2021, with a remaining weighted average amortization period of approximately 2.1 years.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of earnings per share related performance over a three-year period. The actual issuance of shares may range from 0-200% of the target number of PSAs granted, based on the terms of the plan and level of achievement of the related performance target. The grant date fair value of PSAs is based upon the market price of the Company’s class A ordinary shares at the date of grant. The performance conditions are not considered in the determination of the grant date fair value for these awards. Compensation expense is recognized over the performance period based on management’s estimate of the number of units expected to vest. Management evaluates its estimate of the actual number of shares expected to be issued at the end of the programs on a quarterly basis. The cumulative effect of the change in estimate is recognized in the period of change as an adjustment to Compensation and benefits in the Consolidated Statements of Income, if necessary. Dividend equivalents are not paid on PSAs.

The following table summarizes the Company’s target PSAs granted and shares that would be issued at current performance levels for PSAs granted during the years ended December 31, 2021, 2020, and 2019, respectively (shares in thousands and dollars in millions, except fair value):

	2021		2020		2019
Target PSAs granted during period	382		500		467
Weighted average fair value per share at date of grant	$	225	$	163	$	165
Number of shares that would be issued based on current performance levels	737		970		888
Unamortized expense, based on current performance levels	$	122	$	51	$	—

During 2021, the Company issued approximately 0.5 million shares in connection with performance achievements related to the 2018-2020 LPP. During 2020, the Company issued approximately 0.6 million shares in connection with performance achievements related to the 2017-2019 LPP cycle. During 2019, the Company issued approximately 0.7 million shares in connection with performance achievements related to the 2016-2018 LPP cycle.

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Derivatives and Hedging

12 Months Ended

Dec. 31, 2021

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives and Hedging

Derivatives and Hedging

The Company is exposed to market risks, including changes in foreign currency exchange rates and interest rates. To manage the risk related to these exposures, the Company enters into various derivative instruments that reduce these risks by creating offsetting exposures. The Company does not enter into derivative transactions for trading or speculative purposes.

Foreign Exchange Risk Management

The Company is exposed to foreign exchange risk when it earns revenues, pays expenses, enters into monetary intercompany transfers or other transactions denominated in a currency that differs from its functional currency. The Company uses foreign exchange derivatives, typically forward contracts, options and cross-currency swaps, to reduce its overall exposure to the effects of currency fluctuations on cash flows. These exposures are hedged, on average, for less than two years. These derivatives are accounted for as hedges, and changes in fair value are recorded each period in Other comprehensive income (loss) in the Consolidated Statements of Comprehensive Income.

The Company also uses foreign exchange derivatives, typically forward contracts and options, to economically hedge the currency exposure of the Company’s global liquidity profile, including monetary assets or liabilities that are denominated in a non-functional currency of an entity, typically on a rolling 90-day basis, but may be for up to one year in the future. These derivatives are not accounted for as hedges, and changes in fair value are recorded each period in Other income in the Consolidated Statements of Income.

The notional and fair values of derivative instruments are as follows (in millions):

	Notional Amount				Net Amount of Derivative Assets Presented in the Statements of Financial Position (1)				Net Amount of Derivative Liabilities Presented in the Statements of Financial Position (2)
As of December 31	2021		2020		2021		2020		2021		2020
Foreign exchange contracts
Accounted for as hedges	$	629	$	633	$	27	$	33	$	—	$	—
Not accounted for as hedges (3)	412		367		2		1		—		1
Total	$	1,041	$	1,000	$	29	$	34	$	—	$	1

(1)Included within Other current assets ($21 million in 2021 and $11 million in 2020) or Other non-current assets ($8 million in 2021 and $23 million in 2020).

(2)Included within Other current liabilities ($1 million in 2020).

(3)These contracts typically are for 90-day durations and executed close to the last day of the most recent reporting month, thereby resulting in nominal fair values at the balance sheet date.

The amounts of derivative gains (losses) recognized in the Consolidated Financial Statements are as follows (in millions):

	2021		2020		2019
Gain (loss) recognized in Accumulated other comprehensive loss	$	—	$	1	$	(9)

The amounts of derivative gains (losses) reclassified from Accumulated other comprehensive loss to the Consolidated Statements of Income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Total revenue	$	(3)	$	(14)	$	(12)
Compensation and benefits	1		—		(1)
Interest expense	—		(1)		(1)
Total	$	(2)	$	(15)	$	(14)

The Company estimates that approximately $5 million of pretax gains currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

The Company recorded a loss of $24 million in 2021, a gain of $1 million in 2020, and a loss of $18 million in 2019 in Other income for foreign exchange derivatives not designated or qualifying as hedges.

Net Investments in Foreign Operations Risk Management

The Company uses non-derivative financial instruments to protect the value of its investments in a number of foreign subsidiaries. The Company has designated a portion of its euro-denominated commercial paper issuances as a non-derivative hedge of the foreign currency exposure of a net investment in its European operations. The change in fair value of the designated portion of the euro-denominated commercial paper due to changes in foreign currency exchange rates is recorded in Foreign currency translation adjustment, a component of Accumulated other comprehensive loss, to the extent it is effective as a hedge. The foreign currency translation adjustment of the hedged net investments is also recorded in Accumulated other comprehensive loss. Ineffective portions of net investment hedges, if any, are reclassified from Accumulated other comprehensive loss into earnings during the period of change.

The Company had no outstanding euro-denominated commercial paper at December 31, 2021 and 2020 designated as a hedge of the foreign currency exposure of its net investment in its European operations. The unrealized gain recognized in Accumulated other comprehensive loss related to the net investment non-derivative hedging instrument was $29 million, as of December 31, 2021 and 2020.

The Company did not reclassify any deferred gains or losses related to net investment hedges from Accumulated other comprehensive loss to earnings for 2021, 2020, and 2019.

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Fair Value Measurements and Financial Instruments

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements and Financial Instruments

Fair Value Measurements and Financial Instruments

Accounting standards establish a three-tier fair value hierarchy that prioritizes the inputs used in measuring fair values as follows:

•Level 1 — observable inputs such as quoted prices for identical assets in active markets;

•Level 2 — inputs other than quoted prices for identical assets in active markets, that are observable either directly or indirectly; and

•Level 3 — unobservable inputs in which there is little or no market data which requires the use of valuation techniques and the development of assumptions.

The following methods and assumptions are used to estimate the fair values of the Company’s financial instruments, including pension assets (refer to Note 11 “Employee Benefits”):

Money market funds consist of institutional prime, treasury, and government money market funds. The Company reviews treasury and government money market funds to obtain reasonable assurance that the fund net asset value is $1 per share and reviews the floating net asset value of institutional prime money market funds for reasonableness.

Cash and cash equivalents consist of cash and institutional short-term investment funds. The Company reviews the short-term investment funds to obtain reasonable assurance that the fund net asset value is $1 per share.

Equity investments consist of equity securities and equity derivatives valued using the closing stock price on a national securities exchange. Over the counter equity derivatives are valued using observable inputs such as underlying prices of the underlying security and volatility. On a sample basis the Company reviews the listing of Level 1 equity securities in the portfolio, agrees the closing stock prices to a national securities exchange, and independently verifies the observable inputs for Level 2 equity derivatives and securities.

Fixed income investments consist of certain categories of bonds and derivatives. Corporate, government, and agency bonds are valued by pricing vendors who estimate fair value using recently executed transactions and proprietary models based on observable inputs, such as interest rate spreads, yield curves, and credit risk. Asset-backed securities are valued by pricing vendors who estimate fair value using DCF models utilizing observable inputs based on trade and quote activity of securities with similar features. Fixed income derivatives are valued by pricing vendors using observable inputs such as interest rates and yield curves. The Company obtains an understanding of the models, inputs, and assumptions used in developing prices provided by its vendors through discussions with the fund managers. The Company independently verifies the observable inputs, as well as assesses assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on internal Company guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These adjustments do not occur frequently and historically are not material to the fair value estimates used in the Consolidated Financial Statements.

Pooled funds consist of various equity, fixed income, and real estate mutual fund type investment vehicles. Pooled investment funds fair value is estimated based on the proportionate share ownership in the underlying net assets of the investment, which is based on the fair value of the underlying securities. The underlying securities typically trade on a national securities exchange or may be valued by the fund managers using applicable models, inputs, and assumptions. The Company gains an understanding of the investment guidelines and valuation policies of the fund and discusses fund performance with pooled fund managers. The Company obtains audited fund manager financial statements, when available. If the pooled fund is designed to replicate a publicly traded index, the Company compares the performance of the fund to the index to assess the reasonableness of the fair value measurement.

Alternative investments consist of limited partnerships, private equity, and hedge funds. Alternative investment fair value is generally estimated based on the proportionate share ownership in the underlying net assets of the investment as determined by the general partner or investment manager. The valuations are based on various factors depending on investment strategy, proprietary models, and specific financial data or projections. The Company obtains audited fund manager financial statements, when available. The Company obtains a detailed understanding of the models, inputs, and assumptions used in developing prices provided by the investment managers, or appropriate party, through regular discussions. The Company also obtains the investment manger’s valuation policies and assesses the assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on the Company’s guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These

adjustments do not occur frequently and historically are not material to the fair value estimates in the Consolidated Financial Statements.

Derivatives are carried at fair value, based upon industry standard valuation techniques that use, where possible, current market-based or independently sourced pricing inputs, such as interest rates, currency exchange rates, or implied volatility.

Annuity contracts consist of insurance group annuity contracts purchased to match the pension benefit payment stream owed to certain selected plan participant demographics within a few major U.K. defined benefit plans. Annuity contracts are valued using a DCF model utilizing assumptions such as discount rate, mortality, and inflation.

Real estate and REITs consist of publicly traded REITs and direct real estate investments. Level 1 REITs are valued using the closing stock price on a national securities exchange. Non-Level 1 values are based on the proportionate share of ownership in the underlying net asset value as determined by the investment manager. The Company independently reviews the listing of Level 1 REIT securities in the portfolio and agrees the closing stock prices to a national securities exchange. The Company gains an understanding of the investment guidelines and valuation policies of the non-Level 1 real estate funds and discusses performance with the fund managers. The Company obtains audited fund manager financial statements, when available. See the description of “Alternative investments” for further detail on valuation procedures surrounding non-Level 1 REITs.

Debt is carried at outstanding principal balance, less any unamortized issuance costs, discount or premium. Fair value is based on quoted market prices or estimates using DCF analyses based on current borrowing rates for similar types of borrowing arrangements.

The following tables present the categorization of the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2021 and December 31, 2020 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,918	$	2,918	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	40	$	—	$	40	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	11	$	—	$	11	$	—

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,781	$	2,781	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Equity investments	$	3	$	—	$	3	$	—
Derivatives (2)
Gross foreign exchange contracts	$	38	$	—	$	38	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	5	$	—	$	5	$	—

(1)Included within Fiduciary assets or Short-term investments in the Consolidated Statements of Financial Position, depending on their nature and initial maturity.

(2)Refer to Note 13 “Derivatives and Hedging” for additional information regarding the Company’s derivatives and hedging activity.

There were no transfers of assets or liabilities between fair value hierarchy levels during 2021 or 2020. The Company recognized no realized or unrealized gains or losses in the Consolidated Statements of Income related to assets and liabilities measured at fair value using unobservable inputs in 2021, 2020, or 2019.

The fair value of debt is classified as Level 2 of the fair value hierarchy. The following table provides the carrying value and fair value for the Company’s term debt (in millions):

	2021				2020
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	499	$	507	$	400	$	401
Long-term debt	$	8,228	$	9,204	$	7,281	$	8,752

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Claims, Lawsuits and Other Contingencies

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Claims, Lawsuits, and Other Contingencies

Claims, Lawsuits, and Other Contingencies

Legal

Aon and its subsidiaries are subject to numerous claims, tax assessments, lawsuits and proceedings that arise in the ordinary course of business, which frequently include E&O claims. The damages claimed in these matters are or may be substantial, including, in many instances, claims for punitive, treble, or extraordinary damages. While Aon maintains meaningful E&O insurance and other insurance programs to provide protection against certain losses that arise in such matters, Aon has exhausted or materially depleted its coverage under some of the policies that protect the Company and, consequently, is self-insured or materially self-insured for some claims. Accruals for these exposures, and related insurance receivables, when applicable, are included in the Consolidated Statements of Financial Position and have been recognized in Other general expense in the Consolidated Statements of Income to the extent that losses are deemed probable and are reasonably estimable. These amounts are adjusted from time to time as developments warrant. Matters that are not probable and reasonably estimable are not accrued for in the financial statements.

The Company has included in the current matters described below certain matters in which (1) loss (including interest and costs) is probable, (2) loss (including interest and costs) is reasonably possible (that is, more than remote but not probable), or (3) there exists the reasonable possibility of loss (including interest and costs) greater than the accrued amount. In addition, the Company may from time to time disclose matters for which the probability of loss could be remote but the claim amounts associated with such matters are potentially significant. The reasonably possible range of loss (including interest and costs) for the matters described below for which loss is estimable, in excess of amounts that are deemed probable and estimable and therefore already accrued, is estimated to be between $0 and $0.8 billion, exclusive of any insurance coverage. These estimates are based on available information as of the date of this filing. As available information changes, the matters for which Aon is able to estimate, and the estimates themselves, may change. In addition, many estimates involve significant judgment and uncertainty. For example, at the time of making an estimate, Aon may only have limited information about the facts underlying the claim and predictions and assumptions about future court rulings and outcomes may prove to be inaccurate. Although

management at present believes that the ultimate outcome of all matters described below, individually or in the aggregate, will not have a material adverse effect on the consolidated financial position of Aon, legal proceedings are subject to inherent uncertainties and unfavorable rulings or other events. Unfavorable resolutions could include substantial monetary or punitive damages imposed on Aon or its subsidiaries. If unfavorable outcomes of these matters were to occur, future results of operations or cash flows for any particular quarterly or annual period could be materially adversely affected.

Current Matters

On October 3, 2017, CCC invoked arbitration to pursue a claim that it asserts against Aon New Zealand. Aon provided insurance broking services to CCC in relation to CCC’s 2010-2011 material damage and business interruption program. In December 2015, CCC settled its property and business interruption claim for its losses arising from the 2010-2011 Canterbury earthquakes against the underwriter of its material damage and business interruption program and the reinsurers of that underwriter. CCC contends that acts and omissions by Aon caused CCC to recover less in that settlement than it otherwise would have. CCC claims damages of approximately NZD 320 million ($218 million at December 31, 2021 exchange rates) plus interest and costs. Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon Hewitt Investment Consulting, Inc, now known as Aon Investments USA, Inc. (“Aon Investments”), Lowe’s Companies, Inc. and the Administrative Committee of Lowe’s Companies, Inc. (collectively “Lowe’s”) were sued on April 27, 2018 in the U.S. District Court for the Western District of North Carolina (the “Court”) in a class action lawsuit brought on behalf of participants in the Lowe’s 401(k) Plan (the “Plan”). Aon Investments provided investment consulting services to Lowe’s under the ERISA. The plaintiffs contend that in 2015 Lowe’s imprudently placed the Hewitt Growth Fund in the Plan’s lineup of investments, the Hewitt Growth Fund underperformed its benchmarks, and that Aon had a conflict of interest in recommending the proprietary fund for the Plan. The plaintiffs allege the Plan suffered over $200 million in investment losses when compared to the eight funds it replaced. The plaintiffs allege that Aon Investments breached its duties of loyalty and prudence pursuant to the ERISA statute. The matter was tried to the Court the last week of June 2021, and the Court entered judgment in favor of Aon on all claims on October 12, 2021. Plaintiffs have filed an appeal with the United States Court of Appeals for the Fourth Circuit. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims.

A retail insurance brokerage subsidiary of Aon was sued on September 6, 2018 in the United States District Court for the Southern District of New York by a client, Pilkington North America, Inc., that sustained damage from a tornado to its Ottawa, Illinois property. The lawsuit seeks between $45 million and $85 million in property and business interruption damages from either its insurer or Aon. The insurer contends that insurance proceeds were limited to $15 million in coverage by a windstorm sub-limit purportedly contained in the policy procured by Aon for Pilkington. The insurer therefore has tendered $15 million to Pilkington and denied coverage for the remainder of the loss. Pilkington sued the insurer and Aon seeking full coverage for the loss from the insurer or, in the alternative, seeking the same damages against Aon on various theories of professional liability if the court finds that the $15 million sub-limit applies to the claim. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon faces legal action arising out of a fatal plane crash in November 2016. Aon U.K. Limited placed an aviation civil liability reinsurance policy for the Bolivian insurer of the airline. After the crash, the insurer determined that there was no coverage under the airline’s insurance policy due to the airline’s breach of various policy conditions. In November 2018, the owner of the aircraft filed a claim in Bolivia against Aon, the airline, the insurer and the insurance broker. The claim is for $16 million plus any liability the owner has to third parties. In November 2019, a federal prosecutor in Brazil filed a public civil action naming three Aon entities as defendants, along with the airline, the insurer, and the lead reinsurer. That claim seeks pecuniary damages for families affected by the crash in the sum of $300 million; or, in the alternative, $50 million; or, in the alternative, $25 million; plus “moral damages” of an equivalent sum. Separately, in March 2020, the Brazilian Federal Senate invited Aon to give evidence to a Parliamentary Commission of Inquiry in an investigation into the accident. Aon is cooperating with that inquiry. In August 2020, 43 individuals (surviving passengers and estates of the deceased) filed a motion in the Circuit Court of the 11th Judicial Circuit in and for Miami-Dade County, Florida, seeking permission to commence proceedings against Aon (and the insurer and reinsurers) for claims totaling $844 million. Finally, in April 2021, representatives of 16 passengers issued a claim against Aon in the High Court in England seeking damages under the Fatal Accidents Act 1976 in the sum of £29 million ($39 million at December 31, 2021 exchange rates). Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

Aon Investments and AGI were sued on September 16, 2020, in the U.S. District Court for the Southern District of New York by the Blue Cross and Blue Shield Association NEBC. Aon Investments and its predecessors provided investment advisory services to NEBC since 2009. The NEBC contends that it suffered investment losses exceeding $2 billion in several Structured Alpha funds managed by AGI and recommended by Aon. The NEBC is pursuing claims against Aon Investments for breach of fiduciary duty and breach of cofiduciary duty. The NEBC alleges that Aon Investments and AGI are jointly and severally liable for damages, which include the restoration of investment losses, disgorgement of fees and profits, and attorneys’ fees. Aon believes that it has meritorious defenses and intends to vigorously defend itself against these claims.

In April 2017, the FCA announced an investigation relating to suspected competition law breaches in the aviation and aerospace broking industry, which, for Aon in 2016, represented less than $100 million in global revenue. The European Commission assumed jurisdiction over the investigation in place of the FCA, and the European Commission has now closed its investigation. Other antitrust agencies outside the E.U. are conducting formal or informal investigations regarding these matters. Aon intends to work diligently with all antitrust agencies concerned to ensure they can carry out their work as efficiently as possible. At this time, in light of the uncertainties and many variables involved, Aon cannot estimate the ultimate impact on our company from these investigations or any related private litigation, nor any damages, penalties, or fines related to them.

Guarantees and Indemnifications

The Company provides a variety of guarantees and indemnifications to its customers and others. The maximum potential amount of future payments represents the notional amounts that could become payable under the guarantees and indemnifications if there were a total default by the guaranteed parties, without consideration of possible recoveries under recourse provisions or other methods. These amounts may bear no relationship to the expected future payments, if any, for these guarantees and indemnifications. Any anticipated amounts payable are included in the Financial Statements and are recorded at fair value.

The Company expects that, as prudent business interests dictate, additional guarantees and indemnifications may be issued from time to time.

Guarantee of Registered Securities

In connection with the Reorganization, on April 1, 2020 Aon plc and Aon Global Holdings plc, a company incorporated under the laws of England and Wales, entered into various agreements pursuant to which they agreed to guarantee the obligations of Aon Corporation arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Global Limited and the obligations of Aon Global Limited arising under issued and outstanding debt securities, which were previously guaranteed solely by Aon Corporation. Those agreements include: (1) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, and Aon Global Holdings plc and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”) (amending and restating the Amended and Restated Indenture, dated April 2, 2012, among Aon Corporation, Aon Global Limited and the Trustee); (2) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 12, 2012, among Aon Corporation, Aon Global Limited plc and the Trustee); (3) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated May 20, 2015, among Aon Corporation, Aon Global Limited and the Trustee); (4) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated November 13, 2015, among Aon Corporation, Aon Global Limited and the Trustee); and (5) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon Global Limited, Aon plc, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 3, 2018, among Aon Corporation, Aon Global Limited and the Trustee).

Sale of the Divested Business

In connection with the sale of the Divested Business, the Company guaranteed future operating lease commitments related to certain facilities assumed by the buyer. The Company is obligated to perform under the guarantees if the Divested Business defaults on such leases at any time during the remainder of the lease agreements, which expire on various dates through 2025. As of December 31, 2021, the undiscounted maximum potential future payments under the lease guarantee were $40 million, with an estimated fair value of $5 million. No cash payments were made in connection with the lease commitments during the year ended December 31, 2021.

Additionally, the Company is subject to performance guarantee requirements under certain client arrangements that were assumed by the buyer. Should the Divested Business fail to perform as required by the terms of the arrangements, the Company would be required to fulfill the remaining contract terms, which expire on various dates through 2023. As of December 31, 2021, the undiscounted maximum potential future payments under the performance guarantees were $52 million, with an estimated fair value of less than $1 million. No cash payments were made in connection to the performance guarantees during the year ended December 31, 2021.

Letters of Credit

Aon has entered into a number of arrangements whereby the Company’s performance on certain obligations is guaranteed by a third party through the issuance of LOCs. The Company had total LOCs outstanding of approximately $75 million at December 31, 2021, and $79 million at December 31, 2020. These LOCs cover the beneficiaries related to certain of Aon’s U.S. and Canadian non-qualified pension plan schemes and secure deductible retentions for Aon’s own workers compensation program. The Company has also obtained LOCs to cover contingent payments for taxes and other business obligations to third parties, and other guarantees for miscellaneous purposes at its international subsidiaries.

Premium Payments

The Company has certain contractual contingent guarantees for premium payments owed by clients to certain insurance companies. The maximum exposure with respect to such contractual contingent guarantees was approximately $153 million at December 31, 2021 compared to $113 million at December 31, 2020.

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Segment Information

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

Segment Information

Segment Information

The Company operates as one segment that includes all of Aon’s operations, which as a global professional services firm provides a broad range of risk, health, and wealth solutions through four solution lines which make up its principal products and services. The CODM assesses the performance of the Company and allocates resources based on one segment: Aon United.

The Company’s reportable operating segment has been determined using a management approach, which is consistent with the basis and manner in which the CODM uses financial information for the purposes of allocating resources and evaluating performance. The CODM assesses performance and allocates resources based on total Aon results against its key four metrics, including organic revenue growth, expense discipline, and collaborative behaviors that maximize value for Aon and its shareholders, regardless of which solution line it benefits.

As Aon operates as one segment, segment profit or loss is consistent with consolidated reporting as disclosed in the Consolidated Statements of Income. Refer to Note 3 “Revenue from Contracts with Customers” for further information on revenue by principal service line.

Consolidated long-lived assets, net by geographic area are as follows (in millions):

As of December 31	Total		United States	Americas other than U.S.	United Kingdom	Ireland	Other Europe, Middle East, & Africa	Asia Pacific
2021	$	1,378	563	121	180	7	293	214
2020	$	1,599	681	127	213	11	357	210

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Summary of Significant Accounting Principles and Practices (Policies)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Basis of Accounting

Basis of Presentation

The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. The Consolidated Financial Statements include the accounts of Aon plc and all of its controlled subsidiaries (“Aon” or the “Company”). Intercompany accounts and transactions have been eliminated. The Consolidated Financial Statements include, in the opinion of management, all adjustments (consisting of normal recurring adjustments and reclassifications) necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows for all periods presented.

References in this report to “Aon,” the “Company,” “we,” “us,” or “our” for time periods prior to April 1, 2020 refer to Aon Global Limited. References in the Financial Statements to “Aon,” the “Company,” “we,” “us,” or “our” for time periods on or after April 1, 2020, refer to Aon plc.

Use of Estimates

Use of Estimates

The preparation of the accompanying Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of reserves and expenses. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management believes its estimates to be reasonable given the current facts available. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, foreign currency exchange rate movements, and the COVID-19 pandemic increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment would, if applicable, be reflected in the Consolidated Financial Statements in future periods.

Revenue Recognition

Revenue Recognition

The Company generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services provided to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several

factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which the Company acts. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services and (2) fees and commissions for administrative and other services provided to or on behalf of insurers. In Aon’s capacity as an insurance and reinsurance broker, the service promised to the customer is placement of an effective insurance or reinsurance policy, respectively. At the completion of the insurance or reinsurance policy placement process once coverage is effective, the customer has obtained control over the services promised by the Company. Judgment is not typically required when assessing whether the coverage is effective. Fees from clients for advice and consulting services are dependent on the extent and value of the services provided. Payment terms for the Company’s principal service lines are discussed below; the Company believes these terms are consistent with current industry practices. Significant financing components are typically not present in Aon’s arrangements.

The Company recognizes revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, the Company assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, the Company allocates consideration based on their relative fair values.

Costs incurred by the Company in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

The Company has elected to apply practical expedients to not disclose the revenue related to unsatisfied performance obligations if (1) the contract has an original duration of 1 year or less, (2) the Company has recognized revenue for the amount in which it has the right to bill, and (3) the variable consideration is allocated entirely to an unsatisfied performance obligation which is recognized as a series of distinct goods or services that form a single performance obligation.

Disaggregation of Revenue

The following is a description of principal service lines from which the Company generates its revenue:

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units transferred and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly, over the term of the arrangement in installments based on deposit or minimum premiums for most treaty reinsurance arrangements.

Health Solutions includes consulting and brokerage, Human Capital, and voluntary benefits and enrollment solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services using input or output measures, including units delivered or time elapsed, to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue from health care exchange arrangements is typically recognized upon successful enrollment

of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

Wealth Solutions includes retirement consulting and pension administration, as well as investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services, or for certain arrangements, at a point in time upon completion of the services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Share-based Compensation Expense

Share-based Compensation Expense

Share-based payments to employees, including grants of RSUs and PSAs, are measured based on grant date fair value. For purposes of measuring share-based compensation expense, the Company considered whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2021, 2020, or 2019. The Company recognizes compensation expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs materially from original estimates.

Pension and Other Post-Retirement Benefits

Pension and Other Postretirement Benefits

The Company records net periodic cost relating to its pension and other postretirement benefit plans based on calculations that include various actuarial assumptions, including discount rates, assumed rates of return on plan assets, inflation rates, mortality rates, compensation increases, and turnover rates. The Company reviews its actuarial assumptions on an annual basis and modifies these assumptions based on current rates and trends. The effects of gains, losses, and prior service costs and credits are amortized over future service periods or future estimated lives if the plans are frozen as reflected in Other income within the Consolidated Statements of Income. The funded status of each plan, calculated as the fair value of plan assets less the benefit obligation, is reflected in the Company’s Consolidated Statements of Financial Position using a December 31 measurement date.

Earnings per Share

Earnings per Share

Basic earnings per share is computed by dividing net income available to ordinary shareholders by the weighted-average number of ordinary shares outstanding, including participating securities, which consist of unvested share awards with non-forfeitable rights to dividends. Diluted earnings per share is computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding, which have been adjusted for the dilutive effect of potentially issuable ordinary shares, including certain contingently issuable shares. The diluted earnings per share calculation reflects the more dilutive effect of either (1) the two-class method that assumes that the participating securities have not been exercised, or (2) the treasury stock method.

Potentially issuable shares are not included in the computation of diluted earnings per share if their inclusion would be antidilutive.

Cash and Cash Equivalents and Short-term Investments

Cash and Cash Equivalents and Short-term Investments

Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments consist of money market funds. The estimated fair value of Cash and cash equivalents and Short-term investments approximates their carrying values.

Fiduciary Assets and Liabilities

Fiduciary Assets and Liabilities

In its capacity as an insurance agent and broker, Aon collects premiums from insureds and, after deducting its commission, remits the premiums to the respective insurers. Aon also collects claims or refunds from insurers on behalf of insureds. Uncollected premiums from insureds and uncollected claims or refunds from insurers are recorded as Fiduciary assets in the Company’s Consolidated Statements of Financial Position. Unremitted insurance premiums and claims are held in a fiduciary capacity and the obligation to remit these funds is recorded as Fiduciary liabilities in the Consolidated Statements of Financial Position.

Allowance for Doubtful Accounts

Allowance for Doubtful AccountsThe Company’s estimate for allowance for credit losses with respect to receivables is based on a combination of factors, including evaluation of forward-looking information, historical write-offs, aging of balances, and other qualitative and quantitative analyses.

Fixed Assets

Fixed Assets

Fixed assets are stated at cost, less accumulated depreciation. Included in this category are certain capitalized costs incurred during the application development stage related to directly obtaining, developing, or enhancing internal use software. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which are generally as follows:

Asset Description	Estimated Useful Life
Software	Lesser of the life of an associated license, or 4 to 7 years
Leasehold improvements	Lesser of estimated useful life or lease term, not to exceed 10 years
Furniture, fixtures and equipment	4 to 10 years
Computer equipment	4 to 6 years
Buildings	35 years
Automobiles	6 years

Goodwill and Intangible Assets

Goodwill and Intangible Assets

Goodwill represents the excess of acquisition cost over the fair value of the net assets acquired in the acquisition of a business. Goodwill is allocated to applicable reporting units. Upon disposition of a business entity, goodwill is allocated to the disposed entity based on the fair value of that entity compared to the fair value of the reporting unit in which it was included. Goodwill is not amortized, but instead is tested for impairment at least annually. The goodwill impairment test is performed at the reporting unit level. The Company may initially perform a qualitative analysis to determine if it is more likely than not that the goodwill balance is impaired. If a qualitative assessment is not performed or if a determination is made that it is not more likely than not that their value of the reporting unit exceeds its carrying amount, then the Company will perform a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit. Any resulting difference will be a charge to Amortization and impairment of intangible assets in the Consolidated Statements of Income in the period in which the determination is made. Fair value is determined using a combination of present value techniques and market prices of comparable businesses.

We classify our intangible assets acquired as either tradenames, customer-related and contract-based, or technology and other. Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Derivatives

Derivatives

Derivative instruments are recognized in the Consolidated Statements of Financial Position at fair value. Where the Company has entered into master netting agreements with counterparties, the derivative positions are netted by counterparties and are reported accordingly in other assets or other liabilities. Changes in the fair value of derivative instruments are recognized in earnings each period, unless the derivative is designated and qualifies as a cash flow or net investment hedge.

The Company has historically designated the following hedging relationships for certain transactions: (1) a hedge of the change in fair value of a recognized asset or liability or firm commitment (“fair value hedge”), (2) a hedge of the variability in cash flows from a recognized variable-rate asset or liability or forecasted transaction (“cash flow hedge”), and (3) a hedge of the net investment in a foreign operation (“net investment hedge”).

In order for a derivative to qualify for hedge accounting, the derivative must be formally designated as a fair value, cash flow, or a net investment hedge by documenting the relationship between the derivative and the hedged item. The documentation must include a description of the hedging instrument, the hedged item, the risk being hedged, Aon’s risk management objective and strategy for undertaking the hedge, and the method for assessing the effectiveness of the hedge. Additionally, the hedge relationship must be expected to be highly effective at offsetting changes in either the fair value or cash flows of the hedged item at both the inception of the hedge and on an ongoing basis. Aon assesses the ongoing effectiveness of its hedges quarterly or more frequently if facts and circumstances require.

For a derivative designated as a fair value hedging instrument, the gain or loss is recognized in earnings in the period of change together with the offsetting loss or gain on the hedged item attributable to the risk being hedged. The effect is to reflect in earnings the extent to which the hedge is not effective in achieving offsetting changes in fair value. For a cash flow hedge that qualifies for hedge accounting, the change in fair value of a hedging instrument is recognized in Accumulated Other Comprehensive Income and subsequently reclassified to earnings in the same period the hedged item impacts earnings. For a net investment hedge, the change in fair value of the hedging instrument is recognized in Accumulate Other Comprehensive Income as part of the cumulative translation adjustment.

Changes in the fair value of a derivative that is not designated as part of a hedging relationship (commonly referred to as an “economic hedge”) are recorded in Other income in the Consolidated Statements of Income in the period of change.

The Company discontinues hedge accounting prospectively when (1) the derivative expires or is sold, terminated, or exercised, (2) the qualifying criteria are no longer met, or (3) management removes the designation of the hedging relationship.

Foreign Currency

Foreign Currency

Certain of the Company’s non-U.S. operations use their respective local currency as their functional currency. These operations that do not have the U.S. dollar as their functional currency translate their financial statements at the current rates of exchange in effect at the balance sheet date and revenues and expenses using rates that approximate those in effect during the period. The resulting translation adjustments are included in Net foreign currency translation adjustments within the Consolidated Statements of Shareholders’ Equity. Further, gains and losses from the remeasurement of monetary assets and liabilities that are denominated in a non-functional currency of that entity are included in Other income within the Consolidated Statements of Income.

Income Taxes

Income Taxes

Deferred income taxes are recognized for the effect of temporary differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted marginal tax rates and laws that are currently in effect. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period when the rate change is enacted.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences,

future taxable income exclusive of reversing temporary differences and carry-forwards, taxable income in carry-back years, and tax planning strategies that are both prudent and feasible.

The Company recognizes the effect of income tax positions only if sustaining those positions is more likely than not. Tax positions that meet the more likely than not recognition threshold but are not highly certain are initially and subsequently measured based on the largest amount of benefit that is greater than 50% likely of being realized upon settlement with the taxing authority. Only information that is available at the reporting date is considered in the Company’s recognition and measurement analysis, and events or changes in facts and circumstances are accounted for in the period in which the event or change in circumstance occurs.

The Company records penalties and interest related to unrecognized tax benefits in Income taxes in the Company’s Consolidated Statements of Income.

Leases

Leases

The Company leases office facilities, equipment, and automobiles under operating and finance leases. The Company’s lease obligations are primarily for the use of office facilities. The Company evaluates if a leasing arrangement exists upon inception of a contract. A contract contains a lease if the contract conveys the right to control the use of identified tangible assets for a period of time in exchange for consideration. Identified property, plant, or equipment may include a physically distinct portion of a larger asset, or a portion of an asset that represents substantially all of the capacity of the asset but is not physically distinct. The Company assesses whether a contract implicitly contains the right to control the use of a tangible asset that is not already owned. In addition, the Company subleases certain real estate properties to third parties, which are classified as operating leases.

The Company’s leases expire at various dates and may contain renewal, expansion or termination options. The exercise of lease renewal and expansion options are typically at the Company’s sole discretion and are only included in the determination of the lease term if the Company is reasonably certain to exercise the option. In addition, the Company’s lease agreements typically do not contain any material residual value guarantees or restrictive covenants.

ROU assets and lease liabilities are based on the present value of the minimum lease payments over the lease term. The Company has elected the practical expedient related to lease and non-lease components, as an accounting policy election for all asset classes, which allows a lessee to not separate non-lease components from lease components and instead account for consideration received in a contract as a single lease component.

The Company made a policy election to not recognize ROU assets and lease liabilities that arise from leases with an initial term of twelve months or less in the Consolidated Statements of Financial Position. However, the Company recognized these lease payments in the Consolidated Statements of Income on a straight-line basis over the lease term and variable lease payments in the period in which the expense was incurred. The Company chose to apply this accounting policy across all classes of underlying assets.

A portion of the Company’s lease agreements include variable lease payments that are not recorded in the initial measurement of the lease liability and ROU asset balances. For real estate arrangements, base rental payments may be escalated according to annual changes in the CPI or other indices. The escalated rental payments based on the estimated CPI at the lease commencement date are included within minimum rental payments; however, changes in CPI are considered variable in nature and are recognized as variable lease costs in the period in which the obligation is incurred. Additionally, real estate lease agreements may include other variable payments related to operating expenses charged by the landlord based on actual expenditures. Information technology equipment agreements may include variable payments based on usage of the equipment. These expenses are also recognized as variable lease costs in the period in which the expense is incurred.

The Company utilizes discount rates to determine the present value of the lease payments based on information available at the commencement date of the lease. As the rate implicit in each lease is not typically readily available, the Company uses an incremental borrowing rate based on factors such as the lease term and the economic environment where the lease exists to determine the appropriate present value of future lease payments. When determining the incremental borrowing rate, the Company considers the rate of interest it would pay on a secured borrowing in an amount equal to the lease payments for the underlying asset under similar terms.

Operating leases are included in Operating lease ROU assets, Other current liabilities, and Non-current operating lease liabilities in the Consolidated Statements of Financial Position. Finance leases are included in Other non-current assets, Other current liabilities, and Other non-current liabilities in the Consolidated Statements of Financial Position.

Principles of Consolidation

Principles of ConsolidationThe accompanying Consolidated Financial Statements include the accounts of Aon plc and those entities in which the Company has a controlling financial interest. To determine if Aon holds a controlling financial interest in an entity, the Company first evaluates if it is required to apply the VIE model to the entity, otherwise, the entity is evaluated under the voting interest model. Where Aon holds rights that give it the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, combined with a variable interest that gives the right to receive potentially significant benefits or the obligation to absorb potentially significant losses, the Company has a controlling financial interest in that VIE. The Company does not consolidate the VIEs and Aon’s interest in VIEs as of December 31, 2021 was insignificant. Aon holds a controlling financial interest in entities that are not VIEs where it, directly or indirectly, holds more than 50% of the voting rights or where it exercises control through substantive participating rights or as a general partner

New Accounting Standards

New Accounting Pronouncements

Adoption of New Accounting Standards

Contract Assets and Contract Liabilities Acquired in a Business Combination

In October 2021, FASB issued new accounting guidance related to the accounting for contract assets and contract liabilities from contracts with customers acquired in a business combination. The new guidance improves the accounting for acquired revenue contracts with customers in a business combination by addressing diversity in practice and inconsistency. The new guidance requires an entity to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with the current accounting standard on revenue from contracts with customers, ASC 606. The new guidance is effective for Aon in the first quarter of 2023, with early adoption permitted. The Company elected to early adopt this guidance in the fourth quarter of 2021. The Company adopted the new guidance on a prospective basis while applying the amendments to all business combinations that occurred during 2021 as required by the new guidance. The early adoption of the new guidance did not have a material impact on the Consolidated Financial Statements.

Fair Value Measurements

Accounting standards establish a three-tier fair value hierarchy that prioritizes the inputs used in measuring fair values as follows:

•Level 1 — observable inputs such as quoted prices for identical assets in active markets;

•Level 2 — inputs other than quoted prices for identical assets in active markets, that are observable either directly or indirectly; and

•Level 3 — unobservable inputs in which there is little or no market data which requires the use of valuation techniques and the development of assumptions.

The following methods and assumptions are used to estimate the fair values of the Company’s financial instruments, including pension assets (refer to Note 11 “Employee Benefits”):

Money market funds consist of institutional prime, treasury, and government money market funds. The Company reviews treasury and government money market funds to obtain reasonable assurance that the fund net asset value is $1 per share and reviews the floating net asset value of institutional prime money market funds for reasonableness.

Cash and cash equivalents consist of cash and institutional short-term investment funds. The Company reviews the short-term investment funds to obtain reasonable assurance that the fund net asset value is $1 per share.

Equity investments consist of equity securities and equity derivatives valued using the closing stock price on a national securities exchange. Over the counter equity derivatives are valued using observable inputs such as underlying prices of the underlying security and volatility. On a sample basis the Company reviews the listing of Level 1 equity securities in the portfolio, agrees the closing stock prices to a national securities exchange, and independently verifies the observable inputs for Level 2 equity derivatives and securities.

Fixed income investments consist of certain categories of bonds and derivatives. Corporate, government, and agency bonds are valued by pricing vendors who estimate fair value using recently executed transactions and proprietary models based on observable inputs, such as interest rate spreads, yield curves, and credit risk. Asset-backed securities are valued by pricing vendors who estimate fair value using DCF models utilizing observable inputs based on trade and quote activity of securities with similar features. Fixed income derivatives are valued by pricing vendors using observable inputs such as interest rates and yield curves. The Company obtains an understanding of the models, inputs, and assumptions used in developing prices provided by its vendors through discussions with the fund managers. The Company independently verifies the observable inputs, as well as assesses assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on internal Company guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These adjustments do not occur frequently and historically are not material to the fair value estimates used in the Consolidated Financial Statements.

Pooled funds consist of various equity, fixed income, and real estate mutual fund type investment vehicles. Pooled investment funds fair value is estimated based on the proportionate share ownership in the underlying net assets of the investment, which is based on the fair value of the underlying securities. The underlying securities typically trade on a national securities exchange or may be valued by the fund managers using applicable models, inputs, and assumptions. The Company gains an understanding of the investment guidelines and valuation policies of the fund and discusses fund performance with pooled fund managers. The Company obtains audited fund manager financial statements, when available. If the pooled fund is designed to replicate a publicly traded index, the Company compares the performance of the fund to the index to assess the reasonableness of the fair value measurement.

Alternative investments consist of limited partnerships, private equity, and hedge funds. Alternative investment fair value is generally estimated based on the proportionate share ownership in the underlying net assets of the investment as determined by the general partner or investment manager. The valuations are based on various factors depending on investment strategy, proprietary models, and specific financial data or projections. The Company obtains audited fund manager financial statements, when available. The Company obtains a detailed understanding of the models, inputs, and assumptions used in developing prices provided by the investment managers, or appropriate party, through regular discussions. The Company also obtains the investment manger’s valuation policies and assesses the assumptions used for reasonableness based on relevant market conditions and internal Company guidelines. If an assumption is deemed unreasonable, based on the Company’s guidelines, it is then reviewed by management and the fair value estimate provided by the vendor is adjusted, if deemed appropriate. These

adjustments do not occur frequently and historically are not material to the fair value estimates in the Consolidated Financial Statements.

Derivatives are carried at fair value, based upon industry standard valuation techniques that use, where possible, current market-based or independently sourced pricing inputs, such as interest rates, currency exchange rates, or implied volatility.

Annuity contracts consist of insurance group annuity contracts purchased to match the pension benefit payment stream owed to certain selected plan participant demographics within a few major U.K. defined benefit plans. Annuity contracts are valued using a DCF model utilizing assumptions such as discount rate, mortality, and inflation.

Real estate and REITs consist of publicly traded REITs and direct real estate investments. Level 1 REITs are valued using the closing stock price on a national securities exchange. Non-Level 1 values are based on the proportionate share of ownership in the underlying net asset value as determined by the investment manager. The Company independently reviews the listing of Level 1 REIT securities in the portfolio and agrees the closing stock prices to a national securities exchange. The Company gains an understanding of the investment guidelines and valuation policies of the non-Level 1 real estate funds and discusses performance with the fund managers. The Company obtains audited fund manager financial statements, when available. See the description of “Alternative investments” for further detail on valuation procedures surrounding non-Level 1 REITs.

Debt is carried at outstanding principal balance, less any unamortized issuance costs, discount or premium. Fair value is based on quoted market prices or estimates using DCF analyses based on current borrowing rates for similar types of borrowing arrangements.

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Basis of Presentation (Tables)

12 Months Ended

Dec. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Error Corrections and Prior Period Adjustments

The impact to the Consolidated Statements of Cash Flows previously filed in Annual Reports on Form 10-K is as follows (in millions):

	Year Ended December 31, 2020						Year Ended December 31, 2019
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	2,783	$	—	$	2,783	$	1,835	$	—	$	1,835
Cash used for investing activities	(679)		—		(679)		(229)		—		(229)
Cash provided by (used for) financing activities	(2,088)		316		(1,772)		(1,493)		1,246		(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	78		219		297		21		42		63
Net increase in cash and cash equivalents and funds held on behalf of clients	94		535		629		134		1,288		1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	790		5,154		5,944		656		3,866		4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	$	884	$	5,689	$	6,573	$	790	$	5,154	$	5,944

The impact to the Consolidated Statements of Cash Flows previously filed in unaudited Quarterly Reports on Form 10-Q is as follows (in millions):

	Three Months Ended March 31, 2021						Six Months Ended June 30, 2021						Nine Months Ended September 30, 2021
	As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised		As Reported		Effect of Change		As Revised
Cash provided by operating activities	$	561	$	—	$	561	$	1,345	$	—	$	1,345	$	1,251	$	—	$	1,251
Cash provided by (used for) investing activities	102		—		102		(27)		—		(27)		(116)		—		(116)
Cash provided by (used for) financing activities	(709)		28		(681)		(1,122)		386		(736)		(1,380)		786		(594)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(16)		(18)		(34)		11		18		29		(30)		(63)		(93)
Net increase (decrease) in cash and cash equivalents and funds held on behalf of clients	(62)		10		(52)		207		404		611		(275)		723		448
Cash and cash equivalents and funds held on behalf of clients at beginning of year	884		5,689		6,573		884		5,689		6,573		884		5,689		6,573
Cash and cash equivalents and funds held on behalf of clients at end of year	$	822	$	5,699	$	6,521	$	1,091	$	6,093	$	7,184	$	609	$	6,412	$	7,021

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Summary of Significant Accounting Principles and Practices (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of Estimated Useful Lives of Assets

Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which are generally as follows:

Asset Description	Estimated Useful Life
Software	Lesser of the life of an associated license, or 4 to 7 years
Leasehold improvements	Lesser of estimated useful life or lease term, not to exceed 10 years
Furniture, fixtures and equipment	4 to 10 years
Computer equipment	4 to 6 years
Buildings	35 years
Automobiles	6 years

Schedule of Other Intangible Assets by Asset Class

Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Other intangible assets by asset class are as follows (in millions):

As of December 31	2021						2020
	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
Customer-related and contract-based	$	2,289	$	1,848	$	441	$	2,337	$	1,775	$	562
Technology and other	407		357		50		435		358		77
Tradenames (1)	14		13		1		14		13		1
Total	$	2,710	$	2,218	$	492	$	2,786	$	2,146	$	640

(1)In 2020, Aon wrote off $1.0 billion of fully amortized tradenames, including the Hewitt and Benfield tradenames. The company no longer expects to receive economic benefits from these tradenames.

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Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

	Years Ended December 31
	2021		2020		2019
Commercial Risk Solutions	$	6,635	$	5,861	$	5,857
Reinsurance Solutions	1,997		1,814		1,686
Health Solutions	2,154		2,067		2,104
Wealth Solutions	1,426		1,341		1,380
Elimination	(19)		(17)		(14)
Total revenue	$	12,193	$	11,066	$	11,013

Consolidated revenue from contracts with customers by geographic area, which is attributed on the basis of where the services are performed, is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	5,459	$	5,032	$	5,016
Americas other than U.S.	1,027		911		919
U.K.	1,681		1,579		1,502
Ireland	127		84		75
Europe, Middle East, & Africa other than U.K. and Ireland	2,565		2,236		2,263
Asia Pacific	1,334		1,224		1,238
Total revenue	$	12,193	$	11,066	$	11,013

Capitalized Contract Cost

Changes in the net carrying amount of costs to fulfill contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	339	$	335
Additions	1,504		1,360
Amortization	(1,478)		(1,360)
Impairment	—		—
Foreign currency translation and other	(4)		4
Balance at end of period	$	361	$	339

Changes in the net carrying amount of costs to obtain contracts with customers are as follows (in millions):

	2021		2020
Balance at beginning of period	$	184	$	171
Additions	59		61
Amortization	(48)		(47)
Impairment	—		—
Foreign currency translation and other	(16)		(1)
Balance at end of period	$	179	$	184

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Other Financial Data (Tables)

12 Months Ended

Dec. 31, 2021

Other Financial Data [Abstract]

Components of Other Income

The components of Other income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Foreign currency remeasurement	$	26	$	(12)	$	9
Gain from disposals of business	142		25		13
Pension and other postretirement	21		13		9
Equity earnings	8		4		4
Extinguishment of debt	—		(7)		—
Financial instruments	(45)		(10)		(35)
Total	$	152	$	13	$	—

Schedule of Allowance for Doubtful Accounts

Changes in the net carrying amount of allowance for doubtful accounts are as follows (in millions):

	2021		2020		2019
Balance at beginning of period	$	98	$	70	$	62
Adoption of new accounting guidance (1)	—		7		—
Adjusted balance at beginning of period	98		77		62
Provision	26		29		27
Accounts written off, net of recoveries	(37)		(6)		(19)
Foreign currency translation and other	3		(2)		—
Balance at end of period	$	90	$	98	$	70

(1) The adoption of the new accounting standard on the measurement of credit losses on January 1, 2020 resulted in addition to the Allowance for doubtful accounts of $7 million. After tax impacts, this resulted in a $6 million decrease to Retained earnings. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” for further information.

Schedule of Other Current Assets

The components of Other current assets are as follows (in millions):

As of December 31	2021		2020
Costs to fulfill contracts with customers(1)	$	361	$	339
Taxes receivable	53		95
Prepaid expenses	137		111
Other	165		79
Total	$	716	$	624

(1)Refer to Note 3 “Revenue from Contracts with Customers” for further information.

Components of Fixed Assets, Net

The components of Fixed assets, net are as follows (in millions):

As of December 31	2021		2020
Software	$	797	$	808
Leasehold improvements	425		375
Computer equipment	268		249
Furniture, fixtures and equipment	279		246
Construction in progress	45		155
Other	33		34
Fixed assets, gross	1,847		1,867
Less: Accumulated depreciation	1,318		1,268
Fixed assets, net	$	529	$	599

Schedule of Other Non-current Assets

The components of Other non-current assets are as follows (in millions):

As of December 31	2021		2020
Costs to obtain contracts with customers (1)	$	179	$	184
Investments	64		74
Leases (2)	63		89
Taxes receivable	95		125
Other	111		138
Total	$	512	$	610

(1)    Refer to Note 3 “Revenue from Contracts with Customers” for further information.

(2) Refer to Note 8 “Lease Commitments” for further information.

Schedule of Other Current Liabilities

The components of Other current liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred revenue (1)	$	321	$	296
Taxes payable	149		80
Leases (2)	213		234
Other	648		561
Total	$	1,331	$	1,171

(1)$553 million and $454 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2021 and December 31, 2020, respectively.

(2)Refer to Note 8 “Lease Commitments” for further information.

Schedule of Other Non-current Liabilities

The components of Other non-current liabilities are as follows (in millions):

As of December 31	2021		2020
Taxes payable (1)	$	609	$	561
Leases (2)	46		65
Compensation and benefits	58		53
Deferred revenue	70		76
Other	127		140
Total	$	910	$	895

(1)Includes $145 million for the non-current portion of the transition tax as of December 31, 2021 and December 31, 2020. Refer to Note 9 “Income Taxes” for further information on the transition tax.

(2)Refer to Note 8 “Lease Commitments” for further information.

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Acquisitions and Dispositions of Businesses (Tables)

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

Consideration Transferred and Preliminary Value of Intangible Assets

The following table includes the preliminary fair values of consideration transferred, assets acquired, and liabilities assumed as a result of the Company’s acquisitions (in millions):

	Year Ended December 31, 2021
Consideration transferred
Cash	$	27
Deferred, contingent, and other consideration	17
Aggregate consideration transferred	$	44
Assets acquired
Goodwill	17
Other intangible assets	13
Other assets (1)	26
Total assets acquired	56
Liabilities assumed
Total liabilities assumed	12
Net assets acquired	$	44

(1)     In the year ended December 31, 2021, cash and cash equivalents of $12 million and funds held on behalf of client of $1 million were acquired.

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Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in the Net Carrying Amount of Goodwill by Operating Segment

The changes in the net carrying amount of goodwill for the years ended December 31, 2021 and 2020, respectively, are as follows (in millions):

Balance as of January 1, 2020	$	8,165
Goodwill related to current year acquisitions	314
Goodwill related to disposals	(3)
Foreign currency translation and other	190
Balance as of December 31, 2020	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434

Schedule of Other Intangible Assets by Asset Class

Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description	Amortization Basis	Estimated Useful Life
Customer-related and contract-based	In line with underlying cash flows	7 to 20 years
Technology and other	Straight-line	5 to 7 years
Tradenames	Straight-line	1 to 3 years

Other intangible assets by asset class are as follows (in millions):

As of December 31	2021						2020
	Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization and Impairment		Net Carrying Amount
Customer-related and contract-based	$	2,289	$	1,848	$	441	$	2,337	$	1,775	$	562
Technology and other	407		357		50		435		358		77
Tradenames (1)	14		13		1		14		13		1
Total	$	2,710	$	2,218	$	492	$	2,786	$	2,146	$	640

(1)In 2020, Aon wrote off $1.0 billion of fully amortized tradenames, including the Hewitt and Benfield tradenames. The company no longer expects to receive economic benefits from these tradenames.

Schedule of Estimated Future Amortization Expense on Intangible Assets

The estimated future amortization for finite-lived intangible assets as of December 31, 2021 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2022	$	100
2023	89
2024	72
2025	59
2026	37
Thereafter	135
Total	$	492

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Debt (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Summary of Outstanding Debt

The following is a summary of outstanding debt (in millions):

As of December 31	2021		2020
Commercial paper	$	665	$	—
2.80% Senior Notes due March 2021 (1)	—		400
2.20% Senior Notes due November 2022 (2)	499		498
4.00% Senior Notes due November 2023	349		349
3.50% Senior Notes due June 2024	598		597
3.875% Senior Notes due December 2025	748		747
2.875% Senior Notes due May 2026 (EUR 500M)	563		606
8.205% Junior Subordinated Notes due January 2027	521		521
4.50% Senior Notes due December 2028	347		347
3.75% Senior Notes due May 2029	745		744
2.80% Senior Notes due May 2030	993		992
2.05% Senior Notes due August 2031	396		—
2.60% Senior Notes due December 2031	496		—
6.25% Senior Notes due September 2040	296		296
4.25% Senior Notes due December 2042	201		200
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	544		544
4.75% Senior Notes due May 2045	593		593
2.90% Senior Notes due August 2051	591		—
Other	—		48
Total debt	9,392		7,729
Less: Short-term debt and current portion of long-term debt	1,164		448
Total long-term debt	$	8,228	$	7,281

(1)The 2.80% Senior Notes due March 2021 were repaid in full on February 16, 2021.

(2)The 2.20% Senior Notes due November 2021 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2021.

Repayments of Long-term Debt

Repayments of total debt as of December 31, 2021 are as follows (in millions):

2022	$	1,165
2023	350
2024	600
2025	750
2026	566
Thereafter	6,077
Total Repayments	9,508
Unamortized discounts, premiums, and debt issuance costs	(116)
Total Debt	$	9,392

Schedule of Commercial Paper

Commercial paper outstanding, which is included in Short-term debt and current portion of long-term debt in the Company’s Consolidated Statements of Financial Position, is as follows (in millions):

As of December 31	2021		2020
Commercial paper outstanding	$	665	$	—

The weighted average commercial paper outstanding and its related interest rates are as follows (in millions, except percentages):

	Years Ended December 31
	2021			2020
Weighted average commercial paper outstanding	$	273		$	343
Weighted average interest rate of commercial paper outstanding	0.01		%	1.47		%

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Lease Commitments (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Assets And Liabilities Of Lessee

The classification of operating and finance lease asset and liability balances within the Consolidated Statements of Financial Position are as follows (in millions):

As of December 31		2021		2020
Assets
Operating lease assets	Operating lease right-of-use assets	$	786	$	911
Finance lease assets	Other non-current assets	63		89
Total lease assets		$	849	$	1,000
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	194	$	204
Finance	Other current liabilities	19		30
Non-current lease liabilities
Operating	Non-current operating lease liabilities	772		897
Finance	Other non-current liabilities	46		65
Total lease liabilities		$	1,031	$	1,196

Lease, Cost

The components of lease costs are as follows (in millions):

	Years Ended December 31
	2021		2020
Operating lease cost	$	217	$	221
Finance lease costs
Amortization of leased assets	26		25
Interest on lease liabilities	1		3
Variable lease cost	49		48
Short-term lease cost (1)	11		10
Sublease income	(31)		(32)
Net lease cost	$	273	$	275

(1) Short-term lease cost does not include expenses related to leases with a lease term of one month or less.

Weighted average remaining lease term and discount rate related to operating and finance leases are as follows:

As of December 31	2021		2020
Weighted average remaining lease term (years)
Operating leases	6.9		7.4
Finance leases	3.6		4.2
Weighted average discount rate
Operating leases	2.8	%	2.9	%
Finance leases	1.0	%	1.0	%

Other cash and non-cash related activities are as follows (in millions):

	Years Ended December 31
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	244	$	236
Financing cash flows for finance leases	$	23	$	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	44	$	146
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	13
Operating lease ROU asset expense (1)	$	142	$	178
Changes in Non-current operating lease liabilities (1)	$	(125)	$	(47)

(1)The Company has recorded non-cash changes in Operating lease ROU assets and Non-current operating lease liabilities through Other assets and liabilities in Cash flows from operations within the Consolidated Statements of Cash Flows.

Lessee Operating Lease Liability Maturity

Maturity analysis of operating and finance leases as of December 31, 2021 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2022	$	207	$	26	$	233
2023	175		20		195
2024	144		18		162
2025	121		10		131
2026	110		—		110
Thereafter	299		—		299
Total undiscounted future minimum lease payments	1,056		74		1,130
Less: Imputed interest	(90)		(9)		(99)
Present value of lease liabilities	$	966	$	65	$	1,031

Finance Lease, Liability, Maturity

Maturity analysis of operating and finance leases as of December 31, 2021 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2022	$	207	$	26	$	233
2023	175		20		195
2024	144		18		162
2025	121		10		131
2026	110		—		110
Thereafter	299		—		299
Total undiscounted future minimum lease payments	1,056		74		1,130
Less: Imputed interest	(90)		(9)		(99)
Present value of lease liabilities	$	966	$	65	$	1,031

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Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income From Continuing Operations Before Income Tax

Income before income tax and the provision for income tax consist of the following (in millions):

	Years Ended December 31
	2021		2020		2019
Income (loss) before income taxes:
Ireland	$	15	$	(86)	$	200
U.K.	549		634		228
U.S.	(818)		(28)		(220)
Other	2,185		1,946		1,662
Total	$	1,931	$	2,466	$	1,870
Income tax expense:
Current:
Ireland	$	2	$	2	$	1
U.K.	50		30		20
U.S. federal	197		126		22
U.S. state and local	72		22		41
Other	291		259		249
Total current tax expense	$	612	$	439	$	333
Deferred tax expense (benefit):
Ireland	$	(1)	$	(1)	$	(1)
U.K.	131		39		35
U.S. federal	(83)		(72)		(20)
U.S. state and local	(30)		(4)		(27)
Other	(6)		47		(23)
Total deferred tax expense (benefit)	$	11	$	9	$	(36)
Total income tax expense	$	623	$	448	$	297

Reconciliation of the Income Tax Provisions based on the U.S. Statutory Corporate Tax Rate to the Provisions Reflected in the Consolidated Financial Statements

The reconciliation to the provisions reflected in the Consolidated Financial Statements is as follows:

	Years Ended December 31
	2021	2020	2019
Statutory tax rate	25.0%	25.0%	19.0%
U.S. state income taxes, net of U.S. federal benefit	1.5	1.0	0.5
Taxes on international operations (1) (4)	(15.4)	(9.8)	(6.0)
Nondeductible expenses	3.3	2.1	1.6
Adjustments to prior year tax requirements	(0.2)	—	0.1
Deferred tax adjustments, including statutory rate changes	3.2	0.7	—
Deferred tax adjustments, international earnings	1.8	0.7	—
Adjustments to valuation allowances	(0.2)	—	1.8
Change in uncertain tax positions	2.1	1.5	2.2
Excess tax benefits related to shared based compensation (2)	(2.4)	(2.2)	(2.8)
U.S. Tax Reform impact (3)	—	—	(0.3)
Capital Losses	—	(1.8)	—
Non-deductible transaction costs	1.1	1.3	—
Non-deductible termination fee	12.9	—	—
Other — net	(0.4)	(0.3)	(0.2)
Effective tax rate	32.3%	18.2%	15.9%

(1)The Company determines the adjustment for taxes on international operations based on the difference between the statutory tax rate applicable to earnings in each foreign jurisdiction and the enacted rate of 25.0%, 25.0% and 19.0% at December 31, 2021, 2020, and 2019, respectively. The benefit to the Company’s effective income tax rate from taxes on international operations relates to benefits from lower-taxed global operations, primarily due to the use of global funding structures and the tax holiday in Singapore.

(2)Excess tax benefits and deficiencies from share-based payment transactions are recognized as income tax expense or benefit in the Company’s Consolidated Statements of Income.

(3)The impact of the Tax Cuts and Jobs Act including adjustments to the Transition Tax.

(4)In July 2020, final U.S. tax regulations were issued regarding the GILTI high tax election, allowing taxpayers to exclude from GILTI the income of a Controlled Foreign Corporation that incurs a foreign tax rate more than 90% of the top U.S. corporate tax rate. A GILTI high tax election may be made on an annual basis, and taxpayers may choose to apply the election to taxable years beginning after December 31, 2017. The Company expects to make the GILTI high-tax election for 2021 and therefore recorded the impact of making the election.

Components of Aon's Deferred Tax Assets and Liabilities

The components of the Company’s deferred tax assets and liabilities are as follows (in millions):

As of December 31	2021		2020
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	581	$	653
Lease liabilities	207		248
Employee benefit plans	160		312
Other accrued expenses	132		103
Accrued interest	97		—
Federal and state benefit of interest from uncertain tax positions (1)	45		37
Deferred revenue	36		36
Investment basis differences	25		28
Lease and service guarantees	1		2
Other	25		17
Total	1,309		1,436
Valuation allowance on deferred tax assets	(230)		(205)
Total	$	1,079	$	1,231
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(243)	$	(291)
Lease right-of-use asset	(173)		(211)
Deferred costs	(159)		(141)
Unremitted earnings	(58)		(37)
Other accrued expenses	(27)		(22)
Unrealized foreign exchange gains	(22)		(26)
Other	(32)		(41)
Total	$	(714)	$	(769)
Net deferred tax asset	$	365	$	462

(1)The $37 million of Federal and state benefit of interest from uncertain tax positions as of December 31, 2020 was previously classified as Other.

Deferred Income Taxes (Assets and Liabilities Netted by Jurisdiction) as Classified in the Consolidated Statements of Financial Position

Deferred income taxes (assets and liabilities have been netted by jurisdiction) have been classified in the Consolidated Statements of Financial Position as follows (in millions):

As of December 31	2021		2020
Deferred tax assets — non-current	766		724
Deferred tax liabilities — non-current	(401)		(262)
Net deferred tax asset	$	365	$	462

Summary of Operating and Capital Loss Carryforwards

The Company had the following carryforwards (in millions):

As of December 31	2021		2020
U.K.
Operating loss carryforwards	$	41	$	266
Capital loss carryforwards	$	573	$	577
Interest carryforwards	$	—	$	121
U.S.
Federal operating loss carryforwards	$	25	$	49
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	1,140	$	1,220
State operating loss carryforwards	$	398	$	378
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	551	$	573
Other Non-U.S.
Operating loss carryforwards	$	301	$	400
Capital loss carryforwards	$	35	$	42
Interest carryforwards	$	26	$	34
Other carryforwards	$	5	$	—

Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits

The following is a reconciliation of the Company’s beginning and ending amount of uncertain tax positions (in millions):

	2021		2020
Balance at January 1	$	321	$	299
Additions based on tax positions related to the current year	33		25
Additions for tax positions of prior years	7		7
Reductions for tax positions of prior years	(4)		(3)
Settlements	—		—
Business combinations	—		—
Lapse of statute of limitations	(10)		(7)
Foreign currency translation	—		—
Balance at December 31	$	347	$	321

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Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Schedule of Repurchase Agreements

The following table summarizes the Company’s share repurchase activity (in millions, except per share data):

	Years Ended December 31
	2021		2020
Shares repurchased	12.4		8.5
Average price per share	$	286.82	$	206.28
Costs recorded to retained earnings
Total repurchase cost	$	3,543	$	1,761
Additional associated costs	—		2
Total costs recorded to retained earnings	$	3,543	$	1,763

Schedule of Components of Weighted Average Number of Shares Outstanding

Weighted average ordinary shares outstanding are as follows (in millions):

	Years Ended December 31
	2021	2020	2019
Basic weighted average ordinary shares outstanding	224.7	231.9	238.6
Dilutive effect of potentially issuable shares	1.4	1.2	2.0
Diluted weighted average ordinary shares outstanding	226.1	233.1	240.6

Components of Accumulated Other Comprehensive Loss, Net of Related Tax

Changes in Accumulated other comprehensive loss by component, net of related tax, are as follows (in millions):

	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2018	(15)		(1,319)		(2,575)		(3,909)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	(10)		15		(287)		(282)
Tax benefit (expense)	1		(1)		58		58
Other comprehensive income (loss) before reclassifications, net	(9)		14		(229)		(224)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	14		—		109		123
Tax expense	(2)		—		(21)		(23)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		88		100
Net current period other comprehensive income (loss)	3		14		(141)		(124)
Balance at December 31, 2019	(12)		(1,305)		(2,716)		(4,033)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	1		258		(255)		4
Tax benefit	—		2		60		62
Other comprehensive income (loss) before reclassifications, net	1		260		(195)		66
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	15		—		125		140
Tax expense	(3)		—		(31)		(34)
Amounts reclassified from accumulated other comprehensive income, net (3)	12		—		94		106
Net current period other comprehensive income (loss)	13		260		(101)		172
Balance at December 31, 2020	$	1	$	(1,045)	$	(2,817)	$	(3,861)
Other comprehensive income (loss) before reclassifications:
Other comprehensive income (loss) before reclassifications	—		(290)		227		(63)
Tax benefit (expense)	—		2		(58)		(56)
Other comprehensive income (loss) before reclassifications, net	—		(288)		169		(119)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income	2		—		142		144
Tax expense	(1)		—		(34)		(35)
Amounts reclassified from accumulated other comprehensive income, net (3)	1		—		108		109
Net current period other comprehensive income (loss)	1		(288)		277		(10)
Balance at December 31, 2021	$	2	$	(1,333)	$	(2,540)	$	(3,871)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Consolidated Statements of Income. Refer to Note 13 “Derivatives and Hedging” for further information regarding the Company’s derivative and hedging activity.

(2)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Other income (expense) in the Consolidated Statements of Income.

(3)It is the Company’s policy to release income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Expense Recognized for Defined Contribution Savings Plans, Included in Compensation and Benefits and Discontinued Operations in the Consolidated Statements of Income

The expense for the significant plans in the U.S., U.K., Netherlands, and Canada is as follows (in millions):

	Years Ended December 31
	2021		2020		2019
U.S.	$	103	$	87	$	98
U.K.	46		42		41
Netherlands and Canada	35		26		25
Total	$	184	$	155	$	164

Changes in Projected Benefit Obligations Fair Value of Plan Assets, Funded Status and Amount Recognized

The following tables provide a reconciliation of the changes in the projected benefit obligations and fair value of assets for the years ended December 31, 2021 and 2020, and a statement of the funded status as of December 31, 2021 and 2020, for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. These plans represent approximately 90% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2021		2020		2021		2020		2021		2020
Change in projected benefit obligation
At January 1	$	5,406	$	4,779	$	3,380	$	3,192	$	1,625	$	1,425
Service cost	1		—		—		—		—		—
Interest cost	65		88		57		85		12		19
Plan amendment	—		3		—		—		—		—
Settlements	(14)		(7)		—		—		—		—
Actuarial (gain) loss	(292)		520		(103)		274		24		112
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(58)		232		—		—		(83)		113
As of December 31	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Accumulated benefit obligation at end of year	$	4,919	$	5,406	$	3,164	$	3,380	$	1,504	$	1,592
Change in fair value of plan assets
At January 1	$	6,652	$	5,959	$	2,276	$	2,066	$	1,497	$	1,303
Actual return on plan assets	(136)		618		211		289		46		109
Employer contributions	9		8		61		92		17		20
Settlements	(14)		(7)		—		—		—		—
Benefit payments	(189)		(209)		(170)		(171)		(47)		(44)
Foreign currency impact	(76)		283		—		—		(83)		109
As of December 31	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Market related value at end of year	$	6,246	$	6,652	$	2,174	$	2,076	$	1,430	$	1,497
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	1,327	$	1,246	$	(786)	$	(1,104)	$	(101)	$	(128)
Unrecognized prior-service cost	40		43		—		—		(6)		(7)
Unrecognized loss	1,215		1,286		1,551		1,812		489		521
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

The following table provides an overview of the accumulated PBO, fair value of plan assets, funded status and net amount recognized as of December 31, 2021 and 2020 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2021		2020
Accumulated projected benefit obligation	$	109	$	117
Fair value of plan assets	17		17
Funded status	(92)		(100)
Unrecognized prior-service credit	(1)		(1)
Unrecognized loss	2		13
Net amount recognized	$	(91)	$	(88)

Amounts Recognized in the Consolidated Statements of Financial Position

Amounts recognized in the Consolidated Statements of Financial Position consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Prepaid benefit cost (1)	$	1,344	$	1,268	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(52)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(16)		(21)		(734)		(1,052)		(96)		(123)
Accumulated other comprehensive loss	1,255		1,329		1,551		1,812		483		514
Net amount recognized	$	2,582	$	2,575	$	765	$	708	$	382	$	386

(1)Included in Prepaid pension.

(2)Included in Other current liabilities.

(3)Included in Pension, other postretirement, and postemployment liabilities.

Amounts Recognized in Accumulated Other Comprehensive Loss that have not yet been Recognized as Components of net Periodic Benefit Cost

Amounts recognized in Accumulated other comprehensive loss (income) that have not yet been recognized as components of net periodic benefit cost at December 31, 2021 and 2020 consist of (in millions):

	U.K.				U.S.				Other
	2021		2020		2021		2020		2021		2020
Net loss	$	1,215	$	1,286	$	1,551	$	1,812	$	489	$	521
Prior service cost (income)	40		43		—		—		(6)		(7)
Total	$	1,255	$	1,329	$	1,551	$	1,812	$	483	$	514

Components of Net Periodic Benefit Cost for the Pension Plans

Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	U.K.						U.S.						Other
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Service cost	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	65		88		109		57		85		108		12		19		27
Expected return on plan assets, net of administration expenses	(137)		(159)		(191)		(130)		(134)		(136)		(32)		(34)		(40)
Amortization of prior-service cost	2		2		1		—		1		2		—		—		—
Amortization of net actuarial loss	32		30		29		78		68		53		15		12		12
Net periodic benefit (income) cost	(37)		(39)		(52)		5		20		27		(5)		(3)		(1)
Settlement expense	5		2		5		—		—		—		—		—		—
Total net periodic benefit cost (income)	$	(32)	$	(37)	$	(47)	$	5	$	20	$	27	$	(5)	$	(3)	$	(1)

Weighted-Average Assumptions Used to Determine Future Benefit Obligations and Net Periodic Benefit Cost

The weighted-average assumptions used to determine benefit obligations are as follows:

	U.K.		U.S. (1)		Other
	2021	2020	2021	2020	2021	2020
Discount rate	1.96%	1.45%	2.23 - 2.80%	1.74 - 2.45%	1.00 - 2.97%	0.38 - 2.47%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.52%	2.12%	N/A	N/A	2.00%	2.00%

(1)U.S. pension plans are frozen and therefore not impacted by compensation increases or price inflation.

The weighted-average assumptions used to determine the net periodic benefit cost are as follows:

	U.K.			U.S.			Other
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Discount rate	1.20%	1.89%	2.95%	1.12 - 1.79%	2.36 - 2.76%	3.92 - 4.26%	0.28 - 2.00%	0.74 - 2.90%	1.89 - 3.88%
Expected return on plan assets, net of administration expenses	2.04%	2.74%	3.64%	2.65 - 6.56%	3.30- 7.04%	7.05%	1.70 - 2.65%	2.10 - 3.10%	2.50 - 4.10%
Rate of compensation increase	3.22 - 3.72%	3.24 - 3.74%	3.73 - 4.23%	N/A	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%	1.00 - 3.00%

Fair Values of Pension Plan Assets

The fair values of the Company’s U.S. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	93	$	93	$	—	$	—
Equity investments:
Equity securities	86		86		—		—
Equity derivatives	19		—		19		—
Pooled funds (2)	548		—		—		—
Fixed income investments:
Corporate bonds	249		—		249		—
Government and agency bonds	230		192		38		—
Pooled funds (2)	838		—		—		—
Other investments:
Real estate (2) (3)	156		—		—		—
Alternative investments (2) (4)	159		—		—		—
Total	$	2,378	$	371	$	306	$	—

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	79	$	79	$	—	$	—
Equity investments:
Equity securities	207		207		—		—
Equity derivatives	62		—		62		—
Pooled funds (2)	640		90		—		—
Fixed income investments:
Corporate bonds	167		—		167		—
Government and agency bonds	233		200		33		—
Pooled funds (2)	543		212		—		—
Other investments:
Real estate (2)(3)	163		—		—		—
Alternative investments (2) (4)	182		—		—		—
Total	$	2,276	$	788	$	262	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of property funds and trusts holding direct real estate investments.

(4)Consists of limited partnerships, private equity, and hedge funds.

The fair values of the Company’s major U.K. pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	872	$	872	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(1,640)		—		(1,640)		—
Government and agency bonds	2,969		2,969		—		—
Annuities	2,305		—		—		2,305
Pooled funds (2)	463		—		—		—
Other investments:
Real estate (2) (4)	130		—		—		—
Pooled funds (2) (5)	1,147		—		—		—
Total	$	6,246	$	3,841	$	(1,640)	$	2,305

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	182	$	182	$	—	$	—
Equity investments:
Pooled funds (2)	4		—		—		—
Fixed income investments:
Derivatives (3)	(1,424)		—		(1,424)		—
Corporate bonds	4		4		—		—
Government and agency bonds	2,872		2,872		—		—
Annuities	2,625		—		—		2,625
Pooled funds (2)	875		—		—		—
Other investments:
Real estate (2) (4)	117		—		—		—
Pooled funds (2) (5)	1,397		4		—		—
Total	$	6,652	$	3,062	$	(1,424)	$	2,625

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of equity securities and equity derivatives, including repurchase agreements.

(4)Consists of property funds and trusts holding direct real estate investments.

(5)Consists of multi-strategy limited partnerships, private equity, hedge funds, and collective investment schemes with a diversified portfolio of cash, equities, equity related securities, derivatives, and/or fixed income securities.

The fair values of the Company’s other major pension plan assets at December 31, 2021 and December 31, 2020, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	29	$	29	$	—	$	—
Equity investments:
Equity securities	72		72		—		—
Pooled funds (2)	316		—		—		—
Fixed income investments:
Government and agency bonds	350		350		—		—
Pooled funds (2)	597		—		—		—
Other investments:
Alternative investments (2) (3)	55		—		—		—
Real estate (2) (4)	11		—		—		—
Total	$	1,430	$	451	$	—	$	—

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents (1)	$	37	$	37	$	—	$	—
Equity investments:
Equity securities	75		75		—		—
Pooled funds (2)	290		—		—		—
Fixed income investments:
Government and agency bonds	395		395		—		—
Pooled funds (2)	627		—		—		—
Other investments:
Alternative investments (2) (3)	63		—		—		—
Real estate (2) (4)	10		—		—		—
Total	$	1,497	$	507	$	—	$	—

(1)Consists of cash and institutional short-term investment funds.

(2)Certain investments measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the above table are intended to permit reconciliation of the fair values to the amounts presented in the plan assets contained in this Note.

(3)Consists of limited partnerships, private equity, and hedge funds.

(4)Consists of property funds and trusts holding direct real estate investments.

Changes in the Level 3 Fair-Value Category

The following table presents the changes in the Level 3 fair-value category in the Company’s U.K. pension plans for the years ended December 31, 2021 and December 31, 2020 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2020	$	1,849
Actual return on plan assets:
Relating to assets still held at December 31, 2020	13
Purchase, sales and settlements-net	682
Foreign exchange	81
Balance at December 31, 2020	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchases, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	$	2,305

Estimated Future Benefit Payments

Estimated future benefit payments for plans, not including voluntary one-time lump sum payments, are as follows at December 31, 2021 (in millions):

	U.K.		U.S.		Other
2022	$	164	$	193	$	47
2023	$	171	$	191	$	48
2024	$	177	$	193	$	49
2025	$	183	$	193	$	50
2026	$	188	$	183	$	52
2027 - 2031	$	1,017	$	882	$	275

Other Information Related to the Company's Other Post-Retirement Benefit Plans

Other information related to the Company’s other postretirement benefit plans are as follows:

	2021	2020	2019
Net periodic benefit cost recognized (millions)	$5	$4	$3
Weighted-average discount rate used to determine future benefit obligations	2.52 - 3.06%	2.10 - 2.58%	2.93 - 3.25%
Weighted-average discount rate used to determine net periodic benefit costs	1.45 - 2.68%	2.93 - 3.25%	3.91 - 4.26%

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Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Share-based Compensation Expense Recognized in Continuing Operations

The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):

	Years Ended December 31
	2021		2020		2019
Restricted share units	$	204	$	186	$	198
Performance share awards	189		116		110
Employee share purchase plans and other (1)	56		10		9
Total share-based compensation expense	449		312		317
Tax benefit	87		61		66
Share-based compensation expense, net of tax	$	362	$	251	$	251

(1) Includes expenses related to the Aon United Growth Ownership Plan.

Restricted Share Unit Activity

The following table summarizes the status of the Company’s RSUs (shares in thousands, except fair value):

	Years Ended December 31
	2021			2020			2019
	Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)		Shares	Fair Value at Date of Grant (1)
Non-vested at beginning of year	3,309	$	163	3,634	$	143	4,208	$	120
Granted	1,257	$	253	1,329	$	185	1,306	$	175
Vested	(1,248)	$	151	(1,426)	$	133	(1,661)	$	113
Forfeited	(243)	$	184	(228)	$	157	(219)	$	131
Non-vested at end of year	3,075	$	203	3,309	$	163	3,634	$	143

(1)Represents per share weighted average fair value of award at date of grant.

Schedule of Performance-based Plans Information

The following table summarizes the Company’s target PSAs granted and shares that would be issued at current performance levels for PSAs granted during the years ended December 31, 2021, 2020, and 2019, respectively (shares in thousands and dollars in millions, except fair value):

	2021		2020		2019
Target PSAs granted during period	382		500		467
Weighted average fair value per share at date of grant	$	225	$	163	$	165
Number of shares that would be issued based on current performance levels	737		970		888
Unamortized expense, based on current performance levels	$	122	$	51	$	—

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Derivatives and Hedging (Tables)

12 Months Ended

Dec. 31, 2021

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Notional and Fair Values of Derivative Instruments

The notional and fair values of derivative instruments are as follows (in millions):

	Notional Amount				Net Amount of Derivative Assets Presented in the Statements of Financial Position (1)				Net Amount of Derivative Liabilities Presented in the Statements of Financial Position (2)
As of December 31	2021		2020		2021		2020		2021		2020
Foreign exchange contracts
Accounted for as hedges	$	629	$	633	$	27	$	33	$	—	$	—
Not accounted for as hedges (3)	412		367		2		1		—		1
Total	$	1,041	$	1,000	$	29	$	34	$	—	$	1

(1)Included within Other current assets ($21 million in 2021 and $11 million in 2020) or Other non-current assets ($8 million in 2021 and $23 million in 2020).

(2)Included within Other current liabilities ($1 million in 2020).

(3)These contracts typically are for 90-day durations and executed close to the last day of the most recent reporting month, thereby resulting in nominal fair values at the balance sheet date.

Derivative Gains (Losses)

The amounts of derivative gains (losses) recognized in the Consolidated Financial Statements are as follows (in millions):

	2021		2020		2019
Gain (loss) recognized in Accumulated other comprehensive loss	$	—	$	1	$	(9)

The amounts of derivative gains (losses) reclassified from Accumulated other comprehensive loss to the Consolidated Statements of Income are as follows (in millions):

	Years Ended December 31
	2021		2020		2019
Total revenue	$	(3)	$	(14)	$	(12)
Compensation and benefits	1		—		(1)
Interest expense	—		(1)		(1)
Total	$	(2)	$	(15)	$	(14)

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Fair Value Measurements and Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities that are Measured at Fair Value on a Recurring Basis

The following tables present the categorization of the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2021 and December 31, 2020 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,918	$	2,918	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	40	$	—	$	40	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	11	$	—	$	11	$	—

			Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money market funds (1)	$	2,781	$	2,781	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Equity investments	$	3	$	—	$	3	$	—
Derivatives (2)
Gross foreign exchange contracts	$	38	$	—	$	38	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	5	$	—	$	5	$	—

(1)Included within Fiduciary assets or Short-term investments in the Consolidated Statements of Financial Position, depending on their nature and initial maturity.

(2)Refer to Note 13 “Derivatives and Hedging” for additional information regarding the Company’s derivatives and hedging activity.

Schedule of Financial Instruments where the Carrying Amounts and Fair Values Differ

The fair value of debt is classified as Level 2 of the fair value hierarchy. The following table provides the carrying value and fair value for the Company’s term debt (in millions):

	2021				2020
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	499	$	507	$	400	$	401
Long-term debt	$	8,228	$	9,204	$	7,281	$	8,752

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Segment Information (Tables)

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

Schedule of Disclosure on Geographic Areas of Fixed Assets and Operating Lease Right-of-Use Asset

Consolidated long-lived assets, net by geographic area are as follows (in millions):

As of December 31	Total		United States	Americas other than U.S.	United Kingdom	Ireland	Other Europe, Middle East, & Africa	Asia Pacific
2021	$	1,378	563	121	180	7	293	214
2020	$	1,599	681	127	213	11	357	210

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Basis of Presentation - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) solutionLine segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Other income	$ 152	$ 13	$ 0
Restructuring reserves		(127)	3
Number of solution lines | solutionLine	4
Number of operating segment | segment	1
Revision of Prior Period, Reclassification, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Decrease of net loss from discontinued operations		1	1
Other income		$ 1	$ 1

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Basis of Presentation - Revision of Previously Issued Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash provided by operating activities	$ 561	$ 1,345	$ 1,251	$ 2,182	$ 2,783	$ 1,835
Cash used for investing activities	102	(27)	(116)	49	(679)	(229)
Cash used for financing activities	(681)	(736)	(594)	(1,924)	(1,772)	(247)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(34)	29	(93)	(235)	297	63
Net increase in cash and cash equivalents and funds held on behalf of clients	(52)	611	448	72	629	1,422
Cash and cash equivalents and funds held on behalf of clients at beginning of year	6,573	6,573	6,573	6,573	5,944	4,522
Cash and cash equivalents and funds held on behalf of clients at end of year	6,521	7,184	7,021	6,645	6,573	5,944
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash provided by operating activities	561	1,345	1,251		2,783	1,835
Cash used for investing activities	102	(27)	(116)		(679)	(229)
Cash used for financing activities	(709)	(1,122)	(1,380)		(2,088)	(1,493)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(16)	11	(30)		78	21
Net increase in cash and cash equivalents and funds held on behalf of clients	(62)	207	(275)		94	134
Cash and cash equivalents and funds held on behalf of clients at beginning of year	884	884	884	884	790	656
Cash and cash equivalents and funds held on behalf of clients at end of year	822	1,091	609		884	790
Effect of Change
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash provided by operating activities	0	0	0		0	0
Cash used for investing activities	0	0	0		0	0
Cash used for financing activities	28	386	786		316	1,246
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(18)	18	(63)		219	42
Net increase in cash and cash equivalents and funds held on behalf of clients	10	404	723		535	1,288
Cash and cash equivalents and funds held on behalf of clients at beginning of year	5,689	5,689	5,689	$ 5,689	5,154	3,866
Cash and cash equivalents and funds held on behalf of clients at end of year	$ 5,699	$ 6,093	$ 6,412		$ 5,689	$ 5,154

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Summary of Significant Accounting Principles and Practices - Additional Information (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Cash and cash equivalents and short-term investments	$ 836.0			$ 1,192.0
Cash and cash equivalents and short term investments, period increase (decrease)	(356.0)
Restricted cash and investments, current	160.0			102.0
Operating funds required to be held by the Company in the U.K.	112.8		£ 84.3	60.2	£ 44.4
Increase (decrease) in operating funds required to be held by the company	45.9	£ 34.3
Premium trust balances	6,100.0			5,700.0
Fiduciary receivables	8,300.0			8,100.0
Allowance for doubtful accounts	$ 90.0			$ 98.0		$ 70.0	$ 62.0

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Summary of Significant Accounting Principles and Practices - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Software | Minimum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	4 years
Software | Maximum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	7 years
Leasehold improvements
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	10 years
Furniture, fixtures and equipment | Minimum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	4 years
Furniture, fixtures and equipment | Maximum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	10 years
Computer equipment | Minimum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	4 years
Computer equipment | Maximum
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	6 years
Buildings
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	35 years
Automobiles
Fixed Assets, net [Line Items]
Fixed assets, original life, weighted-average	6 years

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Summary of Significant Accounting Principles and Practices - Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2021
Customer-related and contract-based | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	20 years
Customer-related and contract-based | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	7 years
Technology and other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	7 years
Technology and other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	5 years
Tradenames | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	3 years
Tradenames | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	1 year

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Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 12,193	$ 11,066	$ 11,013
U.S.
Disaggregation of Revenue [Line Items]
Total revenue	5,459	5,032	5,016
Americas other than U.S.
Disaggregation of Revenue [Line Items]
Total revenue	1,027	911	919
U.K.
Disaggregation of Revenue [Line Items]
Total revenue	1,681	1,579	1,502
Ireland
Disaggregation of Revenue [Line Items]
Total revenue	127	84	75
Europe, Middle East, & Africa other than U.K. and Ireland
Disaggregation of Revenue [Line Items]
Total revenue	2,565	2,236	2,263
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	1,334	1,224	1,238
Elimination
Disaggregation of Revenue [Line Items]
Total revenue	(19)	(17)	(14)
Commercial Risk Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	6,635	5,861	5,857
Reinsurance Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	1,997	1,814	1,686
Health Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	2,154	2,067	2,104
Wealth Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,426	$ 1,341	$ 1,380

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Revenue from Contracts with Customers - Contract Assets Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Capitalized Cost To Fulfill Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	$ 339	$ 335
Additions	1,504	1,360
Amortization	(1,478)	(1,360)
Impairment	0	0
Foreign currency translation and other	(4)	4
Balance at end of period	361	339
Capitalized Cost To Obtain Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	184	171
Additions	59	61
Amortization	(48)	(47)
Impairment	0	0
Foreign currency translation and other	(16)	(1)
Balance at end of period	$ 179	$ 184

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Other Financial Data - Schedule of Other Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Financial Data [Abstract]
Foreign currency remeasurement	$ 26	$ (12)	$ 9
Gain from disposal of business	142	25	13
Pension and other postretirement	21	13	9
Equity earnings	8	4	4
Extinguishment of debt	0	(7)	0
Financial instruments	(45)	(10)	(35)
Total	$ 152	$ 13	$ 0

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Other Financial Data - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 98	$ 70	$ 62
Provision	26	29	27
Accounts written off, net of recoveries	(37)	(6)	(19)
Foreign currency translation and other	3	(2)	0
Balance at end of period	90	98	70
Allowance for doubtful accounts	90	98	70		$ 62
Cumulative adjustment amount to decrease retained earnings	(1,158)	(3,583)	(3,449)		(4,219)
Retained Earnings (Accumulated Deficit)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Cumulative adjustment amount to decrease retained earnings	1,694	(1,042)	(1,254)		(2,093)
Cumulative Effect, Period of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	0	7	0
Balance at end of period		0	7
Allowance for doubtful accounts		0	7	$ 7	0
Cumulative adjustment amount to decrease retained earnings			6
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings (Accumulated Deficit)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Cumulative adjustment amount to decrease retained earnings			6	$ 6
Cumulative Effect, Period of Adoption, Adjusted Balance
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 98	77	62
Balance at end of period		98	77
Allowance for doubtful accounts		$ 98	77		$ 62
Cumulative adjustment amount to decrease retained earnings			(3,443)
Cumulative Effect, Period of Adoption, Adjusted Balance | Retained Earnings (Accumulated Deficit)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Cumulative adjustment amount to decrease retained earnings			$ (1,248)

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Other Financial Data - Schedule of Other Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Other Financial Data [Abstract]
Costs to fulfill contracts with customers	$ 361	$ 339
Taxes receivable	53	95
Prepaid expenses	137	111
Other	165	79
Total	$ 716	$ 624

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Other Financial Data - Components of Fixed Assets, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 1,847	$ 1,867
Less: Accumulated depreciation	1,318	1,268
Fixed assets, net	529	599
Depreciation of fixed assets	179	167	$ 172
Software
Fixed Assets, net [Line Items]
Fixed assets, gross	797	808
Leasehold improvements
Fixed Assets, net [Line Items]
Fixed assets, gross	425	375
Computer equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	268	249
Furniture, fixtures and equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	279	246
Construction in progress
Fixed Assets, net [Line Items]
Fixed assets, gross	45	155
Other
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 33	$ 34

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Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Other Financial Data [Abstract]
Costs to obtain contracts with customers	$ 179	$ 184
Investments	64	74
Leases	63	89
Taxes receivable	95	125
Other	111	138
Total	$ 512	$ 610

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Other Financial Data - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Financial Data [Abstract]
Deferred revenue	$ 321	$ 296
Taxes payable	149	80
Leases (2)	213	234
Other	648	561
Total	1,331	1,171
Deferred revenue recognized	$ 553	$ 454

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Other Financial Data - Schedule of Other Non-current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Other Financial Data [Abstract]
Taxes payable	$ 609	$ 561
Leases (2)	46	65
Compensation and benefits	58	53
Deferred revenue	70	76
Other	127	140
Other non-current liabilities	910	895
Transition tax for accumulated foreign earnings, noncurrent	$ 145	$ 145

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Acquisitions and Dispositions of Businesses - Completed Acquisitions (Details) $ in Millions		12 Months Ended
	Sep. 01, 2021 USD ($)	Dec. 31, 2021 acquisition	Dec. 31, 2020 acquisition	Dec. 22, 2021	Apr. 06, 2020	Jan. 31, 2020	Jan. 03, 2020	Jan. 01, 2020
Business Acquisition [Line Items]
Number of business acquired under business combination | acquisition		2	6
Weighted average useful life		9 years
For Welfare S.r.l
Business Acquisition [Line Items]
Percentage of capital acquired				100.00%
Aon India Insurance Brokers Limited
Business Acquisition [Line Items]
Percentage of capital acquired	51.00%
Equity interest in acquiree, percentage	49.00%
Equity interest in acquiree | $	$ 15
Farmington Administrative Services LLC
Business Acquisition [Line Items]
Percentage of capital acquired					100.00%
Cytelligence Inc.
Business Acquisition [Line Items]
Percentage of capital acquired						100.00%
Cover Wallet Inc.
Business Acquisition [Line Items]
Percentage of capital acquired							100.00%
TRIUM GmbH Insurance Broker
Business Acquisition [Line Items]
Percentage of capital acquired								100.00%
Assimedia SA
Business Acquisition [Line Items]
Percentage of capital acquired								100.00%
Apollo Conseilet Courtage
Business Acquisition [Line Items]
Percentage of capital acquired								100.00%

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Acquisitions and Dispositions of Businesses - Schedule of Net Assets Acquired (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets acquired
Goodwill	$ 8,434	$ 8,666	$ 8,165
2021 And 2020 Acquisitions
Consideration transferred
Cash	27
Deferred, contingent, and other consideration	17
Aggregate consideration transferred	44
Assets acquired
Goodwill	17
Other intangible assets	13
Other assets	26
Total assets acquired	56
Liabilities assumed
Total liabilities assumed	12
Net assets acquired	44
Cash and cash equivalents	12
Funds held on behalf of client	$ 1

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Acquisitions and Dispositions of Businesses - Completed Dispositions (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) disposition	Dec. 31, 2020 USD ($) disposition	Dec. 31, 2019 USD ($) disposition
Business Combination and Asset Acquisition [Abstract]
Number of dispositions | disposition	6	1	8
Gain from disposal of business | $	$ 142	$ 25	$ 13

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Acquisitions and Dispositions of Businesses - Other Significant Activity (Details) $ in Billions	Jul. 26, 2021 USD ($)
Business Combination and Asset Acquisition [Abstract]
Termination fee	$ 1

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Goodwill and Other Intangible Assets - Schedule of changes in the net carrying amount of goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 8,666	$ 8,165
Goodwill related to current year acquisitions	17	314
Goodwill related to disposals	(37)	(3)
Foreign currency translation and other	(212)	190
Balance at the end of the period	$ 8,434	$ 8,666

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Goodwill and Other Intangible Assets - Schedule of other intangible assets by asset class (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,710	$ 2,786
Accumulated Amortization and Impairment	2,218	2,146
Net Carrying Amount	492	640
Amortization and impairment of intangible assets	147	246	$ 392
Customer-related and contract-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,289	2,337
Accumulated Amortization and Impairment	1,848	1,775
Net Carrying Amount	441	562
Technology and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	407	435
Accumulated Amortization and Impairment	357	358
Net Carrying Amount	50	77
Tradenames
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	14	14
Accumulated Amortization and Impairment	13	13
Net Carrying Amount	$ 1	1
Impairment of intangible assets		$ 1,000

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Goodwill and Other Intangible Assets - Schedule of estimated future amortization expense on intangible assets (Details) $ in Millions	Dec. 31, 2021 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 100
2023	89
2024	72
2025	59
2026	37
Thereafter	135
Total	$ 492

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Debt - Summary of outstanding debt (Details)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€)	Dec. 02, 2021 USD ($)	Aug. 23, 2021 USD ($)	Jan. 13, 2021 USD ($)	Dec. 31, 2020 USD ($)	May 12, 2020 USD ($)
Debt Instrument [Line Items]
Total debt	$ 9,392,000,000					$ 7,729,000,000
Less: Short-term debt and current portion of long-term debt	1,164,000,000					448,000,000
Total long-term debt	8,228,000,000					7,281,000,000
Other
Debt Instrument [Line Items]
Total debt	$ 0					48,000,000
2.80% Senior Notes due March 2021 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.80%	2.80%			2.80%
Total debt	$ 0					400,000,000
Debt face value					$ 400,000,000
2.20% Senior Notes due November 2022 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.20%	2.20%
Total debt	$ 499,000,000					498,000,000
4.00% Senior Notes due November 2023 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.00%	4.00%
Total debt	$ 349,000,000					349,000,000
3.50% Senior Notes due June 2024 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	3.50%	3.50%
Total debt	$ 598,000,000					597,000,000
3.875% Senior Notes due December 2025 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	3.875%	3.875%
Total debt	$ 748,000,000					747,000,000
2.875% Senior Notes due May 2026 (EUR 500M) | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.875%	2.875%
Total debt	$ 563,000,000					606,000,000
Debt face value | €		€ 500,000,000
8.205% Junior Subordinated Notes due January 2027 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	8.205%	8.205%
Total debt	$ 521,000,000					521,000,000
4.50% Senior Notes due December 2028 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.50%	4.50%
Total debt	$ 347,000,000					347,000,000
3.75% Senior Notes due May 2029 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	3.75%	3.75%
Total debt	$ 745,000,000					744,000,000
2.80% Senior Notes due May 2030 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.80%	2.80%					2.80%
Total debt	$ 993,000,000					992,000,000
Debt face value							$ 1,000,000,000
2.05% Senior Notes due August 2031 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.05%	2.05%		2.05%
Total debt	$ 396,000,000					0
Debt face value				$ 400,000,000
2.60% Senior Notes due December 2031 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.60%	2.60%	2.60%
Total debt	$ 496,000,000					0
Debt face value			$ 500,000,000
6.25% Senior Notes due September 2040 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	6.25%	6.25%
Total debt	$ 296,000,000					296,000,000
4.25% Senior Notes due December 2042 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.25%	4.25%
Total debt	$ 201,000,000					200,000,000
4.45% Senior Notes due May 2043 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.45%	4.45%
Total debt	$ 247,000,000					247,000,000
4.60% Senior Notes due June 2044 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.60%	4.60%
Total debt	$ 544,000,000					544,000,000
4.75% Senior Notes due May 2045 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.75%	4.75%
Total debt	$ 593,000,000					593,000,000
2.90% Senior Notes due August 2051 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.90%	2.90%		2.90%
Total debt	$ 591,000,000					0
Debt face value				$ 600,000,000
Commercial paper
Debt Instrument [Line Items]
Total debt	$ 665,000,000					$ 0

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Debt - Narrative (Details)			12 Months Ended
	Jul. 27, 2021 USD ($)	May 29, 2020 USD ($)	Dec. 31, 2021 USD ($) credit_facility	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 EUR (€) credit_facility	Dec. 02, 2021 USD ($)	Sep. 28, 2021 USD ($)	Aug. 23, 2021 USD ($)	Jan. 13, 2021 USD ($)	May 12, 2020 USD ($)
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 0	$ 7,000,000	$ 0
Number of credit facilities | credit_facility			2			2
Line of credit facility, maximum borrowing capacity								$ 900,000,000
Payment of termination fee	$ 400,000,000
Credit Facility Expiring October 2023
Debt Instrument [Line Items]
Line of credit outstanding			$ 0
Credit Facility Expiring February 2022
Debt Instrument [Line Items]
Line of credit outstanding			0
U. S. Program | Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 1,000,000,000	$ 900,000,000
European Program | Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | €						€ 625,000,000
Senior Notes | 2.60% Senior Notes due December 2031
Debt Instrument [Line Items]
Debt face value							$ 500,000,000
Debt interest rate percentage (as a percent)			2.60%			2.60%	2.60%
Senior Notes | 2.05% Senior Notes due August 2031
Debt Instrument [Line Items]
Debt face value									$ 400,000,000
Debt interest rate percentage (as a percent)			2.05%			2.05%			2.05%
Senior Notes | 2.90% Senior Notes due August 2051
Debt Instrument [Line Items]
Debt face value									$ 600,000,000
Debt interest rate percentage (as a percent)			2.90%			2.90%			2.90%
Senior Notes | 2.80% Senior Notes due March 2021
Debt Instrument [Line Items]
Debt face value										$ 400,000,000
Debt interest rate percentage (as a percent)			2.80%			2.80%				2.80%
Senior Notes | 5.00% Senior Notes due September 2020
Debt Instrument [Line Items]
Debt face value		$ 600,000,000
Debt interest rate percentage (as a percent)		5.00%
Loss on extinguishment of debt		$ 7,000,000
Senior Notes | 2.80% Senior Notes due May 2030
Debt Instrument [Line Items]
Debt face value											$ 1,000,000,000
Debt interest rate percentage (as a percent)			2.80%			2.80%					2.80%
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, available credit			$ 1,750,000,000
Line of Credit | Credit Facility Expiring September 2026
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			1,000,000,000
Line of Credit | Credit Facility Expiring October 2023
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 750,000,000

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Debt - Repayments of long-term debt (Details) $ in Millions	Dec. 31, 2021 USD ($)
Debt Disclosure [Abstract]
2022	$ 1,165
2023	350
2024	600
2025	750
2026	566
Thereafter	6,077
Total Repayments	9,508
Unamortized discounts, premiums, and debt issuance costs	(116)
Total Debt	$ 9,392

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Debt - Schedule of Commercial Paper (Details) - Commercial paper - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Commercial paper outstanding	$ 665.0	$ 0.0
Weighted average commercial paper outstanding	$ 273.0	$ 343.0
Weighted average interest rate of commercial paper outstanding	0.01%	1.47%

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Lease Commitments - Assets and Liabilities of Lessee (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets
Operating lease assets	$ 786	$ 911
Finance lease assets	63	89
Total lease assets	$ 849	$ 1,000
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other non-current assets	Other non-current assets
Current lease liabilities
Operating	$ 194	$ 204
Finance	$ 19	$ 30
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Non-current lease liabilities
Operating	$ 772	$ 897
Finance	$ 46	$ 65
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities
Total lease liabilities	$ 1,031	$ 1,196

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Lease Commitments - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease cost	$ 217	$ 221
Finance lease costs
Amortization of leased assets	26	25
Interest on lease liabilities	1	3
Variable lease cost	49	48
Short-term lease cost	11	10
Sublease income	(31)	(32)
Net lease cost	$ 273	$ 275

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Lease Commitments - Lease Terms and Assumptions (Details)	Dec. 31, 2021	Dec. 31, 2020
Weighted average remaining lease term (years)
Operating leases	6 years 10 months 24 days	7 years 4 months 24 days
Finance leases	3 years 7 months 6 days	4 years 2 months 12 days
Weighted average discount rate
Operating leases	2.80%	2.90%
Finance leases	1.00%	1.00%

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Lease Commitments - Cash Flow of Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$ 244	$ 236
Financing cash flows for finance leases	23	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	44	146
ROU assets obtained in exchange for new finance lease liabilities	0	13
Operating lease ROU asset expense	142	178
Changes in Non-current operating lease liabilities	$ (125)	$ (47)

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Lease Commitments - Lease Maturity (Details) $ in Millions	Dec. 31, 2021 USD ($)
Operating Leases
2022	$ 207
2023	175
2024	144
2025	121
2026	110
Thereafter	299
Total undiscounted future minimum lease payments	1,056
Less: Imputed interest	(90)
Present value of lease liabilities	966
Finance Leases
2022	26
2023	20
2024	18
2025	10
2026	0
Thereafter	0
Less: Imputed interest	74
Less: Imputed interest	(9)
Present value of lease liabilities	65
Total
2022	233
2023	195
2024	162
2025	131
2026	110
Thereafter	299
Total undiscounted future minimum lease payments	1,130
Less: Imputed interest	(99)
Present value of lease liabilities	$ 1,031

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Income Taxes - Income from continuing operations before income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income (loss) before income taxes:
Income before income taxes	$ 1,931	$ 2,466	$ 1,870
Current:
Total current tax expense	612	439	333
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	11	9	(36)
Total income tax expense	623	448	297
Ireland
Income (loss) before income taxes:
Income before income taxes	15	(86)	200
Current:
Total current tax expense	2	2	1
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(1)	(1)	(1)
U.K.
Income (loss) before income taxes:
Income before income taxes	549	634	228
Current:
Total current tax expense	50	30	20
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	131	39	35
U.S. federal
Income (loss) before income taxes:
Income before income taxes	(818)	(28)	(220)
Current:
Total current tax expense	197	126	22
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(83)	(72)	(20)
U.S. state and local
Current:
Total current tax expense	72	22	41
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(30)	(4)	(27)
Other
Income (loss) before income taxes:
Income before income taxes	2,185	1,946	1,662
Current:
Total current tax expense	291	259	249
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	$ (6)	$ 47	$ (23)

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Income Taxes - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Statutory tax rate	25.00%	25.00%	19.00%
Increase in valuation allowance	$ 25
Unremitted earnings	58	$ 37
Benefit realized from tax holiday granted	$ 104	$ 97	$ 90
Earnings per share impact of tax holiday (in dollars per share)	$ 0.46	$ 0.42	$ 0.37
Unrecognized tax benefits that would impact effective tax rate	$ 295	$ 270	$ 248
Accrued potential interest and penalties	22	21	24
Liability recorded for interest and penalties	$ 142	$ 120	$ 99

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Income Taxes - Reconciliation of the income tax provisions based on the U.S. statutory corporate tax rate to the provisions reflected in the Consolidated Financial Statements (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of the income tax provisions based on the statutory corporate tax rate to the provisions reflected in the Consolidated Financial Statements
Statutory tax rate	25.00%	25.00%	19.00%
U.S. state income taxes, net of U.S. federal benefit	1.50%	1.00%	0.50%
Taxes on international operations	(15.40%)	(9.80%)	(6.00%)
Nondeductible expenses	3.30%	2.10%	1.60%
Adjustments to prior year tax requirements	(0.20%)	0.00%	0.10%
Deferred tax adjustments, including statutory rate changes	3.20%	0.70%	0.00%
Deferred tax adjustments, international earnings	1.80%	0.70%	0.00%
Adjustments to valuation allowances	(0.20%)	0.00%	1.80%
Change in uncertain tax positions	2.10%	1.50%	2.20%
Excess tax benefits related to shared based compensation	(2.40%)	(2.20%)	(2.80%)
U.S. Tax Reform impact	0	0	(0.003)
Capital Losses	0	(0.018)	0
Non-deductible transaction costs	0.011	0.013	0
Non-deductible termination fee	12.90%	0.00%	0.00%
Other — net	(0.40%)	(0.30%)	(0.20%)
Effective tax rate	32.30%	18.20%	15.90%

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Income Taxes - Components of Aon's deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$ 581	$ 653
Lease liabilities	207	248
Employee benefit plans	160	312
Other accrued expenses	132	103
Accrued interest	97	0
Federal and state benefit of interest from uncertain tax positions	45	37
Deferred revenue	36	36
Investment basis differences	25	28
Lease and service guarantees	1	2
Other	25	17
Total	1,309	1,436
Valuation allowance on deferred tax assets	(230)	(205)
Total	1,079	1,231
Deferred tax liabilities:
Intangibles and property, plant and equipment	(243)	(291)
Lease right-of-use asset	(173)	(211)
Deferred costs	(159)	(141)
Unremitted earnings	(58)	(37)
Other accrued expenses	(27)	(22)
Unrealized foreign exchange gains	(22)	(26)
Other	(32)	(41)
Total	(714)	(769)
Net deferred tax asset	$ 365	462
Federal and state benefit of interest from uncertain tax positions		$ 37

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Income Taxes - Deferred income taxes (assets and liabilities netted by jurisdiction) as classified in the Consolidated Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Deferred tax assets — non-current	$ 766	$ 724
Deferred tax liabilities — non-current	(401)	(262)
Net deferred tax asset	$ 365	$ 462

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Income Taxes Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
U.K.
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 41	$ 266
Capital loss carryforwards	573	577
Interest carryforwards	0	121
U.S. Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	25	49
Capital loss carryforwards	112	112
Interest carryforwards	1,140	1,220
U.S. State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	398	378
Capital loss carryforwards	123	123
Interest carryforwards	551	573
Other
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	301	400
Capital loss carryforwards	35	42
Interest carryforwards	26	34
Other carryforwards	$ 5	$ 0

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Income Taxes - Reconciliation of the beginning and ending amount of unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of the Company's beginning and ending amount of unrecognized tax benefits
Balance at the beginning of the period	$ 321	$ 299
Additions based on tax positions related to the current year	33	25
Additions for tax positions of prior years	7	7
Reductions for tax positions of prior years	(4)	(3)
Settlements	0	0
Business combinations	0	0
Lapse of statute of limitations	(10)	(7)
Foreign currency translation	0	0
Balance at the end of the period	$ 347	$ 321

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Shareholders' Equity - Distributable Profits (Details) - USD ($) $ in Millions	Dec. 31, 2021	Jul. 26, 2021	Dec. 31, 2020
Equity [Abstract]
Distributable profits approved amount		$ 34,000
Distributable reserves available amount	$ 32,700		$ 200

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Shareholders' Equity - Ordinary Shares (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended				12 Months Ended		33 Months Ended
	Feb. 18, 2022	Nov. 30, 2020	Jun. 30, 2017	Nov. 30, 2014	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2020	Apr. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Share repurchase authorization amount		$ 27,500,000,000						$ 5,000,000,000
Share repurchase authorization amount, increase during period		$ 5,000,000,000	$ 5,000,000,000	$ 5,000,000,000
Number of shares repurchased (in shares)					12.4	8.5	149.6
Average price per share (in dollars per share)					$ 286.82	$ 206.28
Costs recorded to retained earnings
Total repurchase cost					$ 3,543,000,000	$ 1,761,000,000	$ 18,300,000,000
Additional associated costs					0	2,000,000
Total costs recorded to retained earnings					3,543,000,000	$ 1,763,000,000
Remaining authorized repurchase amount					$ 1,700,000,000
Subsequent Event
Accumulated Other Comprehensive Income (Loss) [Line Items]
Share repurchase authorization amount, increase during period	$ 7,500,000,000

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Shareholders' Equity - Schedule of weighted average shares outstanding (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Basic weighted average ordinary shares outstanding (in shares)	224.7	231.9	238.6
Dilutive effect of potentially issuable shares (in shares)	1.4	1.2	2.0
Diluted weighted average ordinary shares outstanding (in shares)	226.1	233.1	240.6
Antidilutive securities excluded from computation of earnings per share (in shares)	0.3	0.0	0.0

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Shareholders' Equity - Components of Accumulated other comprehensive loss, net of related tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 3,583	$ 3,449	$ 4,219
Other comprehensive income (loss) before reclassifications	(63)	4	(282)
Tax benefit (expense)	(56)	62	58
Other comprehensive income (loss) before reclassifications, net	(119)	66	(224)
Amounts reclassified from accumulated other comprehensive income	144	140	123
Tax expense	(35)	(34)	(23)
Amounts reclassified from accumulated other comprehensive income (loss), net	109	106	100
Total other comprehensive income (loss) attributable to Aon shareholders	(10)	172	(124)
Ending Balance	1,158	3,583	3,449
Change in Fair Value of Investments
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	1	(12)	(15)
Other comprehensive income (loss) before reclassifications	0	1	(10)
Tax benefit (expense)	0	0	1
Other comprehensive income (loss) before reclassifications, net	0	1	(9)
Amounts reclassified from accumulated other comprehensive income	2	15	14
Tax expense	(1)	(3)	(2)
Amounts reclassified from accumulated other comprehensive income (loss), net	1	12	12
Total other comprehensive income (loss) attributable to Aon shareholders	1	13	3
Ending Balance	2	1	(12)
Foreign Currency Translation Adjustments
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,045)	(1,305)	(1,319)
Other comprehensive income (loss) before reclassifications	(290)	258	15
Tax benefit (expense)	2	2	(1)
Other comprehensive income (loss) before reclassifications, net	(288)	260	14
Amounts reclassified from accumulated other comprehensive income	0	0	0
Tax expense	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net	0	0	0
Total other comprehensive income (loss) attributable to Aon shareholders	(288)	260	14
Ending Balance	(1,333)	(1,045)	(1,305)
Post-retirement Benefit Obligations
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(2,817)	(2,716)	(2,575)
Other comprehensive income (loss) before reclassifications	227	(255)	(287)
Tax benefit (expense)	(58)	60	58
Other comprehensive income (loss) before reclassifications, net	169	(195)	(229)
Amounts reclassified from accumulated other comprehensive income	142	125	109
Tax expense	(34)	(31)	(21)
Amounts reclassified from accumulated other comprehensive income (loss), net	108	94	88
Total other comprehensive income (loss) attributable to Aon shareholders	277	(101)	(141)
Ending Balance	(2,540)	(2,817)	(2,716)
AOCI attributable to parent
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(3,861)	(4,033)	(3,909)
Ending Balance	$ (3,871)	$ (3,861)	$ (4,033)

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Employee Benefits - Schedule of expense recognized in Compensation and benefit in the Consolidated Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	$ 184	$ 155	$ 164
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	103	87	98
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	46	42	41
Netherlands and Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	$ 35	$ 26	$ 25

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Employee Benefits - Pension Plans Narrative (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Nov. 30, 2020 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percentage of the Company's projected benefit obligation	90.00%
Pension Plan | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plans with PBO in excess of plan assets, PBO	$ 3,200		$ 3,300
Plans with ABO in excess of the fair value of plan assets, ABO	3,200		3,300
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets	2,400		2,200
Non-cash settlement charge	0		0		$ 0
Payment for settlements	0		0
Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated retirement benefits covered by insurance contract, impact amount							$ 94
Plans with PBO in excess of plan assets, PBO	17		54
Plans with ABO in excess of the fair value of plan assets, ABO	17		54
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets			32
Non-cash settlement charge	5	£ 3	2	£ 2	5	£ 4
Payment for settlements	14		7
Pension Plan | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plans with PBO in excess of plan assets, PBO	1,500		1,600
Plans with ABO in excess of the fair value of plan assets, ABO	409		443
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets	326		342
Plans with PBO in excess of plan assets, plan assets	1,400		1,400
Non-cash settlement charge	0		0		$ 0
Payment for settlements	$ 0		$ 0

XML

Employee Benefits - Reconciliation of the changes in the benefit obligations and fair value of assets and a statement of the funded status (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
U.S.
Change in projected benefit obligation
Balance at the beginning of the Period	$ 3,380	$ 3,192
Service cost	0	0	$ 0
Interest cost	57	85	108
Plan amendment	0	0
Settlements	0	0
Actuarial (gain) loss	(103)	274
Benefit payments	(170)	(171)
Foreign currency impact	0	0
Balance at the end of the period	3,164	3,380	3,192
Accumulated benefit obligation at end of year	3,164	3,380
Change in fair value of plan assets
Balance at the beginning of the period	2,276	2,066
Actual return on plan assets	211	289
Employer contributions	61	92
Settlements	0	0
Benefit payments	(170)	(171)
Foreign currency impact	0	0
Balance at the end of the period	2,378	2,276	2,066
Market related value at end of year	2,174	2,076
Funded status	(786)	(1,104)
Unrecognized prior-service cost	0	0
Unrecognized loss	1,551	1,812
Net amount recognized	765	708
U.K.
Change in projected benefit obligation
Balance at the beginning of the Period	5,406	4,779
Service cost	1	0	0
Interest cost	65	88	109
Plan amendment	0	3
Settlements	(14)	(7)
Actuarial (gain) loss	(292)	520
Benefit payments	(189)	(209)
Foreign currency impact	(58)	232
Balance at the end of the period	4,919	5,406	4,779
Accumulated benefit obligation at end of year	4,919	5,406
Change in fair value of plan assets
Balance at the beginning of the period	6,652	5,959
Actual return on plan assets	(136)	618
Employer contributions	9	8
Settlements	(14)	(7)
Benefit payments	(189)	(209)
Foreign currency impact	(76)	283
Balance at the end of the period	6,246	6,652	5,959
Market related value at end of year	6,246	6,652
Funded status	1,327	1,246
Unrecognized prior-service cost	40	43
Unrecognized loss	1,215	1,286
Net amount recognized	2,582	2,575
Other
Change in projected benefit obligation
Balance at the beginning of the Period	1,625	1,425
Service cost	0	0	0
Interest cost	12	19	27
Plan amendment	0	0
Settlements	0	0
Actuarial (gain) loss	24	112
Benefit payments	(47)	(44)
Foreign currency impact	(83)	113
Balance at the end of the period	1,531	1,625	1,425
Accumulated benefit obligation at end of year	1,504	1,592
Change in fair value of plan assets
Balance at the beginning of the period	1,497	1,303
Actual return on plan assets	46	109
Employer contributions	17	20
Settlements	0	0
Benefit payments	(47)	(44)
Foreign currency impact	(83)	109
Balance at the end of the period	1,430	1,497	$ 1,303
Market related value at end of year	1,430	1,497
Funded status	(101)	(128)
Unrecognized prior-service cost	(6)	(7)
Unrecognized loss	489	521
Net amount recognized	$ 382	$ 386

XML

Employee Benefits - Amounts recognized in the Consolidated Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	$ 1,366	$ 1,280
Pension Plan | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	0	0
Accrued benefit liability - current	(52)	(52)
Accrued benefit liability - non-current	(734)	(1,052)
Accumulated other comprehensive loss	1,551	1,812
Net amount recognized	765	708
Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	1,344	1,268
Accrued benefit liability - current	(1)	(1)
Accrued benefit liability - non-current	(16)	(21)
Accumulated other comprehensive loss	1,255	1,329
Net amount recognized	2,582	2,575
Pension Plan | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	0	0
Accrued benefit liability - current	(5)	(5)
Accrued benefit liability - non-current	(96)	(123)
Accumulated other comprehensive loss	483	514
Net amount recognized	$ 382	$ 386

XML

Employee Benefits - Amounts recognized in Accumulated other comprehensive loss that have not yet been recognized (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
U.S.
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	$ 1,551	$ 1,812
Prior service cost (income)	0	0
Net amount recognized	1,551	1,812
U.K.
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	1,215	1,286
Prior service cost (income)	40	43
Net amount recognized	1,255	1,329
Other
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	489	521
Prior service cost (income)	(6)	(7)
Net amount recognized	$ 483	$ 514

XML

Employee Benefits - Components of net periodic benefit cost (Details) - Pension Plan £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0		$ 0		$ 0
Interest cost	57		85		108
Expected return on plan assets, net of administration expenses	(130)		(134)		(136)
Amortization of prior-service cost	0		1		2
Amortization of net actuarial loss	78		68		53
Net periodic benefit (income) cost	5		20		27
Settlement expense	0		0		0
Total net periodic benefit cost (income)	5		20		27
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1		0		0
Interest cost	65		88		109
Expected return on plan assets, net of administration expenses	(137)		(159)		(191)
Amortization of prior-service cost	2		2		1
Amortization of net actuarial loss	32		30		29
Net periodic benefit (income) cost	(37)		(39)		(52)
Settlement expense	5	£ 3	2	£ 2	5	£ 4
Total net periodic benefit cost (income)	(32)		(37)		(47)
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0		0		0
Interest cost	12		19		27
Expected return on plan assets, net of administration expenses	(32)		(34)		(40)
Amortization of prior-service cost	0		0		0
Amortization of net actuarial loss	15		12		12
Net periodic benefit (income) cost	(5)		(3)		(1)
Settlement expense	0		0		0
Total net periodic benefit cost (income)	$ (5)		$ (3)		$ (1)

XML

Employee Benefits - Weighted-average assumptions used to determine future benefit obligations (Details) - Pension Plan	Dec. 31, 2021	Dec. 31, 2020
U.S. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.23%	1.74%
U.S. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.80%	2.45%
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.96%	1.45%
Underlying price inflation	2.52%	2.12%
U.K. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.62%	3.22%
U.K. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	4.12%	3.72%
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Underlying price inflation	2.00%	2.00%
Other | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.00%	0.38%
Rate of compensation increase	1.00%	1.00%
Other | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.97%	2.47%
Rate of compensation increase	3.00%	3.00%

XML

Employee Benefits - Weighted-average assumptions used to determine the net periodic benefit cost (Details) - Pension Plan	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets, net of administration expenses	6.56%		7.05%
U.S. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.12%	2.36%	3.92%
Expected return on plan assets, net of administration expenses	2.65%	3.30%
U.S. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.79%	2.76%	4.26%
Expected return on plan assets, net of administration expenses	6.56%	7.04%
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.20%	1.89%	2.95%
Expected return on plan assets, net of administration expenses	2.04%	2.74%	3.64%
U.K. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.22%	3.24%	3.73%
U.K. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.72%	3.74%	4.23%
Other | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	0.28%	0.74%	1.89%
Expected return on plan assets, net of administration expenses	1.70%	2.10%	2.50%
Rate of compensation increase	1.00%	1.00%	1.00%
Other | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.00%	2.90%	3.88%
Expected return on plan assets, net of administration expenses	2.65%	3.10%	4.10%
Rate of compensation increase	3.00%	3.00%	3.00%

XML

Employee Benefits - Expected Return on Plan Assets Narrative (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2019
Pension Plan | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets, net of administration expenses	6.56%	7.05%

XML

Employee Benefits - Schedule of Fair Value of U.S Plan Assets (Details) - Pension Plan - U.S. - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	$ 2,378	$ 2,276	$ 2,066
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	93	79
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	86	207
Equity derivatives
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	19	62
Equity investments, Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	548	640
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	249	167
Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	230	233
Fixed Income Investments, Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	838	543
Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	156	163
Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	159	182
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	371	788
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	93	79
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	86	207
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity derivatives
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity investments, Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	90
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	192	200
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Income Investments, Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	212
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	306	262
Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2) | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2) | Equity derivatives
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	19	62
Significant Other Observable Inputs (Level 2) | Equity investments, Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2) | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	249	167
Significant Other Observable Inputs (Level 2) | Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	38	33
Significant Other Observable Inputs (Level 2) | Fixed Income Investments, Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Other Observable Inputs (Level 2) | Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Equity derivatives
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Equity investments, Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Fixed Income Investments, Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3) | Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	$ 0	$ 0

XML

Employee Benefits - Schedule of Fair Value of U.K. Plan Assets (Details) - Pension Plan - U.K. - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 6,246	$ 6,652	$ 5,959
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	3,841	3,062
Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(1,640)	(1,424)
Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	2,305	2,625	$ 1,849
Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	872	182
Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	872	182
Cash and cash equivalents | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Cash and cash equivalents | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	4
Equity investments, Pooled funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Derivatives
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(1,640)	(1,424)
Derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Derivatives | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(1,640)	(1,424)
Derivatives | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Corporate bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets		4
Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets		4
Corporate bonds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets		0
Corporate bonds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets		0
Government and agency bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	2,969	2,872
Government and agency bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	2,969	2,872
Government and agency bonds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Government and agency bonds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Annuities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	2,305	2,625
Annuities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Annuities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Annuities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	2,305	2,625
Fixed Income Investments, Pooled Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	463	875
Fixed Income Investments, Pooled Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Fixed Income Investments, Pooled Funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Fixed Income Investments, Pooled Funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	130	117
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Other Investments, Pooled Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	1,147	1,397
Other Investments, Pooled Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	4
Other Investments, Pooled Funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Other Investments, Pooled Funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 0	$ 0

XML

Employee Benefits - Schedule of changes in Level 3 fair value for U.K. Pension Plans (Details) - Pension Plan - U.K. - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Actual return on plan assets:
Balance at the beginning of the period	$ 6,652	$ 5,959
Foreign exchange	(76)	283
Balance at the end of the period	6,246	6,652
Significant Unobservable Inputs (Level 3)
Actual return on plan assets:
Balance at the beginning of the period	2,625	1,849
Relating to assets still held at the end of the year	(286)	13
Purchases, sales and settlements-net	0	682
Foreign exchange	(34)	81
Balance at the end of the period	$ 2,305	$ 2,625

XML

Employee Benefits - Schedule of Fair Value of Other Plan Assets (Details) - Pension Plan - Other - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 1,430	$ 1,497	$ 1,303
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	451	507
Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	29	37
Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	29	37
Cash and cash equivalents | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Cash and cash equivalents | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	72	75
Equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	72	75
Equity securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	316	290
Equity investments, Pooled funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Equity investments, Pooled funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Government and agency bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	350	395
Government and agency bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	350	395
Government and agency bonds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Government and agency bonds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Fixed Income Investments, Pooled Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	597	627
Fixed Income Investments, Pooled Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Fixed Income Investments, Pooled Funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Fixed Income Investments, Pooled Funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	55	63
Alternative investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Alternative investments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Alternative investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	11	10
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate | Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	0	0
Real estate | Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 0	$ 0

XML

Employee Benefits - Investment Policy and Strategy Narrative (Details)	Dec. 31, 2021
Foreign Plan | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual allocation percentage	6.00%
Foreign Plan | Fixed income investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual allocation percentage	88.00%
Foreign Plan | Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual allocation percentage	6.00%
Pension Plan | U.S. | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	31.00%
Pension Plan | U.S. | Fixed income investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	54.00%
Pension Plan | U.S. | Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	15.00%

XML

Employee Benefits - Cash Flows Narrative (Details) - Pension Plan $ in Millions	Dec. 31, 2021 USD ($)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	$ 52
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	7
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	$ 15

XML

Employee Benefits - Estimated Future Benefit Payments (Details) - Pension Plan $ in Millions	Dec. 31, 2021 USD ($)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022	$ 193
2023	191
2024	193
2025	193
2026	183
2027 - 2031	882
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022	164
2023	171
2024	177
2025	183
2026	188
2027 - 2031	1,017
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022	47
2023	48
2024	49
2025	50
2026	52
2027 - 2031	$ 275

XML

Employee Benefits - Overview of the accumulated benefit obligation, fair value of plan assets, funded status and net amount recognized for U.S. and Canadian Other Post-Retirement Benefits (Details) - Other Post-Retirement Benefits - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated projected benefit obligation	$ 109	$ 117
Fair value of plan assets	17	17
Funded status	(92)	(100)
Unrecognized prior-service credit	(1)	(1)
Unrecognized loss	2	13
Net amount recognized	$ (91)	$ (88)

XML

Employee Benefits - Schedule of Other information related to Company's other post-retirement plan's (Details) - Other Post-Retirement Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost recognized (millions)	$ 5	$ 4	$ 3
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted-average discount rate used to determine future benefit obligations	2.52%	2.10%	2.93%
Weighted-average discount rate used to determine net periodic benefit costs	1.45%	2.93%	3.91%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted-average discount rate used to determine future benefit obligations	3.06%	2.58%	3.25%
Weighted-average discount rate used to determine net periodic benefit costs	2.68%	3.25%	4.26%

XML

Employee Benefits - U.S. and Canadian Other Post-Retirement Benefits Narrative (Details) - Other Post-Retirement Benefits $ in Millions	Dec. 31, 2021 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected amortization of prior service credit, next fiscal year	$ 0.9
Amounts in Accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost in next fiscal year	0.2
Expected employer contributions during next fiscal year	5.0
Expected future benefit payments 2022	5.0
Expected future benefit payments 2026 – 2030	$ 25.0

XML

Share-Based Compensation Plans - Share-based compensation expense recognized in continuing operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 449	$ 312	$ 317
Tax benefit	87	61	66
Share-based compensation expense, net of tax	362	251	251
Employee share purchase plans and other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	56	10	9
Restricted share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	204	186	198
Performance share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 189	$ 116	$ 110

XML

Share-Based Compensation Plans - Restricted Share Units Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining amortization period (in years)	2 years 1 month 6 days
Restricted share units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of RSUs vested during the period	$ 189	$ 190	$ 187
Unamortized deferred compensation	$ 447
Restricted share units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted share units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years

XML

Share-Based Compensation Plans - Summary of the status of the Company's RSUs (Details) - Restricted share units - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Non-vested share awards
Non-vested at beginning of period (in shares)	3,309	3,634	4,208
Granted (in shares)	1,257	1,329	1,306
Vested (in shares)	(1,248)	(1,426)	(1,661)
Forfeited (in shares)	(243)	(228)	(219)
Non-vested at end of period (in shares)	3,075	3,309	3,634
Fair Value at Date of Grant
Non-vested at beginning of period (in dollars per share)	$ 163	$ 143	$ 120
Granted (in dollars per share)	253	185	175
Vested (in dollars per share)	151	133	113
Forfeited (in dollars per share)	184	157	131
Non-vested at end of period (in dollars per share)	$ 203	$ 163	$ 143

XML

Share-Based Compensation Plans - Performance Share Awards Narrative (Details) - Performance-based Awards - shares shares in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSA, vesting conditions period (in years)	3 years
Leadership Performance Plan Cycle 2018-2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	0.5
Leadership Performance Plan Cycle 2017-2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)		0.6
Leadership Performance Plan Cycle 2016-2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)			0.7
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSA, actual shares issued, percent	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSA, actual shares issued, percent	200.00%

XML

Share-Based Compensation Plans - Schedule of Performance-based plans (Details) - Performance-based Awards - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target PSAs granted (in shares)	382	500	467
Fair value (in dollars per share)	$ 225	$ 163	$ 165
Number of shares that would be issued based on current performance levels (in shares)	737	970	888
Unamortized expense, based on current performance levels	$ 122	$ 51	$ 0

XML

Derivatives and Hedging - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months	$ 5
Gain (loss) on derivative	$ (45)		$ (10)		$ (35)
Gross foreign exchange contracts | Not accounted for as hedges
Derivative [Line Items]
Derivative term of contract	90 days	90 days
Gain (loss) on derivative	$ (24)		1		$ (18)
Gross foreign exchange contracts | Not accounted for as hedges | Maximum
Derivative [Line Items]
Derivative term of contract	1 year	1 year
Cash Flow Hedging
Derivative [Line Items]
Foreign currency exposures, maximum average hedging period (in years)	2 years	2 years
Net Investment Hedging
Derivative [Line Items]
Outstanding Euro-denominated commercial paper | €		€ 0		€ 0
Unrealized gain recognized in AOCI	$ 29		$ 29

XML

Derivatives and Hedging - Notional and fair values of derivative instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Current Assets
Derivative [Line Items]
Derivative assets	$ 21	$ 11
Other Noncurrent Assets
Derivative [Line Items]
Derivative assets	8	23
Other Current Liabilities
Derivative [Line Items]
Derivative liabilities		1
Accounted for as hedges | Gross foreign exchange contracts
Derivative [Line Items]
Derivative, Notional Amount	629	633
Derivative assets	27	33
Derivative liabilities	0	0
Not accounted for as hedges
Derivative [Line Items]
Derivative, Notional Amount	1,041	1,000
Derivative assets	29	34
Derivative liabilities	0	1
Not accounted for as hedges | Gross foreign exchange contracts
Derivative [Line Items]
Derivative, Notional Amount	412	367
Derivative assets	2	1
Derivative liabilities	$ 0	$ 1
Derivative term of contract	90 days

XML

Derivatives and Hedging - Schedule of amounts of derivative gains (losses) recognized in the Consolidated Financial Statements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Gain (loss) recognized in Accumulated other comprehensive loss	$ 0	$ 1
Gain (loss) recognized in Accumulated other comprehensive loss			$ (9)
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	(2)	(15)	(14)
Total revenue
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	(3)	(14)	(12)
Compensation and benefits
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	1	0	(1)
Interest expense
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	$ 0	$ (1)	$ (1)

XML

Fair Value Measurements and Financial Instruments - Schedule of assets and liabilities that are measured at fair value on a recurring basis (Details) - Recurring - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Money market funds
Assets
Money market funds	$ 2,918	$ 2,781
Government bonds
Assets
Other investments	1	1
Equity investments
Assets
Other investments		3
Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	40	38
Liabilities
Gross foreign exchange contracts	11	5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets
Money market funds	2,918	2,781
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government bonds
Assets
Other investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity investments
Assets
Other investments		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	0	0
Liabilities
Gross foreign exchange contracts	0	0
Significant Other Observable Inputs (Level 2) | Money market funds
Assets
Money market funds	0	0
Significant Other Observable Inputs (Level 2) | Government bonds
Assets
Other investments	1	1
Significant Other Observable Inputs (Level 2) | Equity investments
Assets
Other investments		3
Significant Other Observable Inputs (Level 2) | Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	40	38
Liabilities
Gross foreign exchange contracts	11	5
Significant Unobservable Inputs (Level 3) | Money market funds
Assets
Money market funds	0	0
Significant Unobservable Inputs (Level 3) | Government bonds
Assets
Other investments	0	0
Significant Unobservable Inputs (Level 3) | Equity investments
Assets
Other investments		0
Significant Unobservable Inputs (Level 3) | Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	0	0
Liabilities
Gross foreign exchange contracts	$ 0	$ 0

XML

Fair Value Measurements and Financial Instruments - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Unrealized gain (loss) related to assets and liabilities measured at fair value using unobservable inputs	$ 0	$ 0	$ 0

XML

Fair Value Measurements and Financial Instruments - Schedule of financial instruments where the carrying amounts and fair values differ (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair value of financial instrument
Current portion of long-term debt	$ 499	$ 400
Fair value current portion of long-term debt	507	401
Long-term debt	8,228	7,281
Fair value of long term debt	$ 9,204	$ 8,752

XML

Claims, Lawsuits, and Other Contingencies - Legal Narrative (Details) £ in Millions, $ in Millions				1 Months Ended					12 Months Ended
	Dec. 31, 2021 USD ($)	Sep. 06, 2018 USD ($)	Oct. 03, 2017 NZD ($)	Apr. 30, 2021 USD ($) plaintiff	Apr. 30, 2021 GBP (£) plaintiff	Aug. 31, 2020 USD ($) plaintiff	Nov. 30, 2019 USD ($) defendant	Nov. 30, 2018 USD ($)	Dec. 31, 2016 USD ($)	Sep. 16, 2020 USD ($)	Apr. 27, 2018 USD ($)
Aviation and Aerospace Broking Industry
Loss Contingencies [Line Items]
Total revenue									$ 100,000,000
Aon Hewitt Investment Consulting, Inc.
Loss Contingencies [Line Items]
Investment losses suffered by plaintiff											$ 200,000,000
Pending Litigation | Christchurch City Council
Loss Contingencies [Line Items]
Value of damages sought	$ 218,000,000		$ 320
Pending Litigation | Fatal Plain Crash In November2016
Loss Contingencies [Line Items]
Value of damages sought				$ 39,000,000	£ 29	$ 844,000,000		$ 16,000,000
Loss contingency, number of defendants | defendant							3
Damages sought option 1							$ 300,000,000
Damages sought option 2							50,000,000
Damages sought option 3							$ 25,000,000
Loss contingency, number of plaintiffs | plaintiff				16	16	43
Pending Litigation | N E B C
Loss Contingencies [Line Items]
Investment losses suffered by plaintiff										$ 2,000,000,000
Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	0
Minimum | Pilkington North America, Inc.
Loss Contingencies [Line Items]
Value of damages sought		$ 45,000,000
Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	$ 800,000,000
Maximum | Pilkington North America, Inc.
Loss Contingencies [Line Items]
Value of damages sought		85,000,000
Damages awarded		$ 15,000,000

XML

Claims, Lawsuits, and Other Contingencies - Guarantees and Indemnifications Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Maximum potential funding under commitments	$ 153,000,000	$ 113,000,000
Discontinued Operations, Disposed of by Sale | Tempo Business | Property Lease Guarantee
Loss Contingencies [Line Items]
Maximum potential funding under commitments	40,000,000
Guarantor obligations, current carrying value	5,000,000
Loss contingency accrual payments	0
Discontinued Operations, Disposed of by Sale | Tempo Business | Performance Guarantee
Loss Contingencies [Line Items]
Maximum potential funding under commitments	52,000,000
Guarantor obligations, current carrying value	1,000,000
Loss contingency accrual payments	$ 0

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Claims, Lawsuits, and Other Contingencies - Letters of Credit Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Letters of credit outstanding	$ 75	$ 79

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Claims, Lawsuits, and Other Contingencies - Premium Payments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Maximum potential funding under commitments	$ 153	$ 113

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Segment Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 revenue_line performance_metric segment
Segment Reporting [Abstract]
Number of reportable segments | segment	1
Number of revenue lines | revenue_line	4
Number of performance metrics measured | performance_metric	4

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Segment Information - Schedule of consolidated non-current assets by geographic area (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	$ 1,378	$ 1,599
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	563	681
Americas other than U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	121	127
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	180	213
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	7	11
Other Europe, Middle East, & Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	293	357
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	$ 214	$ 210