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, 2022
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 2.85% Senior Notes due 2027	AON27	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 Corporation and Aon Global Holdings plc’s 5.00% Senior Notes due 2032	AON32	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
Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052	AON52	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, 2022, the aggregate market value of the registrant’s Class A Ordinary Shares held by non-affiliates of the registrant was $57,066,496,679 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 16, 2023: 205,142,379.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s proxy statement for its 2023 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, all of 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; litigation and regulatory matters; pension obligations; cash flow and liquidity; expected effective tax rate; expected foreign currency translation impacts; 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, that could impact results include:

•changes in the competitive environment, due to macroeconomic conditions or otherwise, or damage to our reputation;

•fluctuations in currency exchange, interest, or inflation 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, including the adoption and implementation in the European Union, the United States, the United Kingdom, or other countries of the Organization for Economic Co-operation and Development tax proposals or other pending proposals in those and other countries, 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 United States, 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;

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

•international risks associated with our global operations, including impacts from military conflicts or political instability, such as the ongoing Russian war in Ukraine;

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

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•any system or network disruption or breach resulting in operational interruption or improper disclosure of confidential, personal, or proprietary data, and resulting liabilities or damage to our reputation;

•our ability to develop, implement, update, and enhance 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 businesses 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 develop and implement innovative growth strategies and initiatives intended to yield cost savings, and the ability to achieve such growth or 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
ASC	Accounting Standards Codification
AUM	Assets Under Management
BPS	Basis Points
CCC	Christchurch City Council
CODM	Chief Operating Decision Maker
CPI	Consumer Price Index
DCF	Discounted Cash Flow
DOL	Department of Labor
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
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 sovereignties 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 Aon Growth Ventures Group.

In 2022, our consolidated total revenue was $12,479 million. This includes $6,715 million in Commercial Risk Solutions, $2,190 million in Reinsurance Solutions, $2,224 million in Health Solutions, and $1,367 million in Wealth Solutions, before certain 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, like Digital Client Solutions, 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, climate, 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, Strategy and Technology Group 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. Strategy and Technology Group combines strategic advice with data-driven consulting, analytics, and modeling tools, including Tyche, ReMetrica, and PathWise, to help clients deploy capital efficiently and effectively. We develop highly customized solutions that help clients drive growth and operational efficiency, improve balance sheet strength and resiliency, and comply with regulatory and operational requirements, including through the execution of reinsurance transactions. Capital markets is a global investment bank with expertise in insurance-linked securities,

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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.

Health Solutions includes consulting and brokerage, consumer benefits 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 wellbeing. 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 and sovereignties, 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. Consumer benefits solutions designs and delivers innovative voluntary consumer benefits that improve an employer’s total rewards strategy and positively impacts their employees’ financial and overall wellbeing. 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, among others, Marsh & McLennan Companies, Inc., Willis Towers Watson Public Limited Company, Arthur J Gallagher & Company, Lockton Companies, Inc., as well as numerous other global, 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

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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.

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, 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 and the DOL 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, DOL, 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 2022. 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 2022.

Aon United, Our Culture, and Human Capital Strategy

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 Aon United strategy defines how Aon colleagues work together to deliver value to clients, setting a new standard for client leadership. Aon United is brought to life through our common client value creation model which scales strategies from across

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the firm to bring the best of Aon to clients. Each year, Aon makes significant philanthropic contributions to various organizations, supports numerous colleague volunteer opportunities, and offers paid time off to volunteer.

Colleagues

As of December 31, 2022, we employed approximately 50,000 employees and conducted our operations in more than 120 countries and sovereignties. 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. Colleagues benefit from our “Smart Working” approach. The aim of Smart Working is to create a healthy, productive, inclusive, and sustainable way of working, enabling colleagues to deliver their best work for clients from wherever they are best placed to do so. This strategy, which supports in person, hybrid, and virtual working, continues to be a source of positive feedback and strong engagement based on colleague surveys.

Training and Development

We invest significant resources to develop the talent needed to remain at the forefront of innovation and remain 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 learning courses to advanced leadership programs, the curriculum is aligned to the Aon United Blueprint and Inclusive People Leader strategy. Aon’s investment in technology and use of virtual based learning and development programs allows us to deliver targeted offerings designed to advance all colleagues’ development.

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, colleague 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 commitments to I&D and belonging.

Our engagement survey process consists of frequent pulse surveys, as well as our annual all colleague support survey which enables us to understand how colleagues are engaging with their teams, the firm, and clients. This outreach effort allows us to gather insights more rapidly, take timely action to address feedback, and deliver on the needs of colleagues in real time – ensuring colleagues feel more connected, more valued and more relevant. The pulse surveys for 2022 were focused on topics such as manager and leadership support, delivering on our Aon Story, colleague wellbeing, I&D, talent acquisition and performance & rewards. Aon’s feedback from our workforce 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, are connected to our formal performance management, and career development approach. These programs serve to reward colleagues for their Aon United impact both in what they accomplish for clients, colleagues, and shareholders, how they achieve those results and how they deliver on our values. We maintain a global commitment to colleague wellbeing 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. 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 I&D initiatives.

Inclusion and Diversity

We believe that inclusive and diverse 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 are aligned to drive actions to increase the diversity of our teams. Our colleague-led Business Resource Groups also support execution and provide additional opportunities for colleagues to enhance our inclusive environment.

As of December 31, 2022, Aon’s global workforce was 54% women and 46% men, and the Aon Executive Committee which leads the firm was 48% women and 52% men. At the manager level, 28% of senior leaders and 43% of managers with one or more direct report were women. New colleague hires for the year were 51% women and 49% men. Aon’s U.S. workforce was 25% 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 18% 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 31% 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 seven 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 160 organizations committed as of December 31, 2022.

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 585 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.

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, actions by central banks, 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 and Reinsurance 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 revenue is 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. In addition, decreased underwriting capacity for insurance and reinsurance may create difficulty for our professionals to place business, which may adversely impact our ability to earn revenue.

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, human resources consulting, 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.

Alliances or mergers among competitors could affect our business. Further, we compete on pricing and the innovation and quality of our service offerings and could be affected by competitors’ lower cost structures, product development activities, and pricing policies, any or all of which could result in better market acceptance of our competitors’ offerings than those that we offer or develop.

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 evolving competition we face, our financial condition or results of operations might be adversely affected.

If we are unable to effectively develop and implement innovative strategies, efficiencies and new solutions for our clients, our reputation, ability to compete effectively and financial condition may be adversely affected.

Developing and implementing innovative strategies, efficient business practices, and new solutions to current and emerging client needs is important to our business. We may be unsuccessful in developing innovative strategies, or our competitors may be more successful in innovating and delivering services to meet new and existing client needs. Competitors may be able to innovate faster and respond better to evolving client demand and industry conditions, or price their services more aggressively 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. If we are unsuccessful in innovating, if we cannot innovate as quickly as our competitors, if we are not able to make sufficient investment in innovation, 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.

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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 have or 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.

In addition, innovation in technology, capabilities, and the entry into new lines of business, services, or products require significant investment and present additional risks to the Company, 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 not be successful and could result in reputational damage to us; 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, including potential E&O or other claims.

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, common law or fiduciary 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 businesses, 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 client may claim it suffered losses due to reliance on our consulting advice or reporting, 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. Adverse statements or claims from clients (including clients in the public sector or whose activities are frequently covered by the press) may receive media attention or other publicity. 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 a class of business, 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

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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 premiums;

•decreases in available underwriting capacity for insurance and reinsurance;

•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 consistently 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 and related expenses. Accordingly, if we are not able to maintain the rates we charge for our services or appropriately manage the staffing costs of our personnel and related expenses, we may not be able to sustain our profit margin and our profitability will suffer. The 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), our ability to develop, attract and retain suitable capabilities and talent, our ability to obtain third party services at favorable prices, our ability to manage key suppliers to maximize delivery, product and efficiency opportunities, inflation (including wage inflation) and the need to devote time and resources to training and professional and business development.

In our investment businesses, 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 businesses provide 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 alleged 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 filed, and may continue to file, individual and class action lawsuits alleging investment consultants have charged excessive fees, given improper advice or taken investment actions 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, publicity and diversion of other resources. If any lawsuit – against the Company or any other investment consultant or asset manager – 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.

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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 “Ireland Reorganization”). At the time of the Ireland Reorganization we expected, and we continue to expect, that the Ireland Reorganization will, among other things, provide greater certainty around ongoing access to existing U.S. treaties with other E.U. member states from which we derive benefit. However, we may not realize the benefits we anticipate from the Ireland 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.

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 $1,142 million at December 31, 2022 and are reported in Cash and cash equivalents and Short-term investments. Of the total balance, $115 million was restricted to its use as of December 31, 2022. Funds held on behalf of clients and insurers were $6.4 billion at December 31, 2022 and are reported in Fiduciary assets. We also carry an investment portfolio of other long-term investments. As of December 31, 2022, these long-term investments had a carrying value of $60 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 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

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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, 2022, we had total consolidated debt outstanding of approximately $10.8 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, 2022, 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. 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 our corporate strategy. Our senior debt ratings at December 31, 2022 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 affect our access to capital and our competitive position.

Our tax assets and liabilities are subject to a variety of different factors, which could create volatility in our global effective 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.

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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., the Inflation Reduction Act introduced, among other changes, a 1% excise tax on certain stock redemptions by U.S. corporations (which the U.S. Treasury indicated may also apply to certain stock redemptions of foreign corporations deemed funded by their U.S. affiliates). The OECD, a global coalition of member countries, proposed a plan to reform international taxation which includes the introduction of a global minimum tax. The OECD recommendations have been nominally accepted by many countries within and without the OECD, but the implementation in each country remains subject to the possibility of significant variation, which could lead to a risk of multiple levels of taxation on Aon’s income. The U.K. and E.U. member states, among others, have introduced draft legislation or otherwise agreed to implement a global minimum tax that would be consistent with the OECD recommendations, beginning, for Aon, in 2024. There remains significant uncertainty as to if, when and how the various OECD proposals will ultimately be enacted. If and when effective, the global minimum tax could have a material adverse effect on our global 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 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 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

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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&Os, 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 and other matters related to our operations. However, we may be unable to maintain, at commercially reasonable rates, our current levels of insurance coverage for E&O claims or other risks in future periods. Also, 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 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, privacy and data protection, trade sanctions laws, restrictions and export controls, anti-money laundering, wage-and-hour standards, employment and labor relations, antitrust and 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

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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.

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

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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 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.

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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 or other epidemics or pandemics, 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 or other epidemics or pandemics 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 we would be subject to undeveloped or evolving legal systems, unstable governments and economies, impacts from geopolitical conflicts, and potential governmental actions affecting the flow of goods, services, and currency.

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 professional personnel remains 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 and may expose us to potential liability for monetary damages. 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.

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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;

•the impacts of geopolitical conflicts;

•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;

•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.

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

Our success depends, in part, on our ability to enhance and implement the 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, data and analytics, industry standards and client preferences. The effort to gain necessary expertise and achieve internal efficiencies through technology and data and analytics require us to incur significant expenses, and we may not be successful in identifying the optimal funding priorities. We make investments in technology and data and analytics to operate our businesses and achieve intended efficiencies; however, our investments and enhancements may not be sufficient to respond needs across all of our businesses. In addition, if we are not successful in developing and maintaining expertise in process excellence, technology and data trends, our business performance may be compromised.

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

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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. Our failure to manage our key suppliers and our day-to-day operations with effective controls, and/or 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, legal, 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 interruption in or the cessation of service by any service provider as a result of systems failures, cybersecurity or data privacy 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 we are unable to identify appropriate acquisition targets, or if our competitors are more successful in identifying acquisition targets at favorable valuations, we may we fail to achieve desired strategic goals, capabilities and efficiencies, and our results of operations might be adversely affected. 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

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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 initiative 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 not be successful and could result in reputational damage to us; 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, including potential E&O or other claims. 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.

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, and increasingly sophisticated attempted attacks to our systems and networks. Aon has 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 (in connection with incident response, remediation efforts, or otherwise) and divert resources to address and

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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 have experienced cyber incidents and 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, there have been a number of recently adopted privacy laws around the globe including in China and, 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 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.

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.

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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 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 shareholders 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. See Note 8 “Lease Commitments” of the Notes

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to Consolidated Financial Statements in Part II, Item 8 of this report for information with respect to our lease commitments as of December 31, 2022.

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.

Item 4.    Mine Safety Disclosure

Not applicable.

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Information about our Executive Officers

The executive officers of Aon, as of February 17, 2023 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	58	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	60	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	51	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	44	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.
Mindy Simon	46	Chief Operating Officer. Ms. Simon joined Aon as Chief Operating Officer in October 2022. Prior to joining Aon, Ms. Simon served as Chief Information Officer for Conagra Brands since June 2017. Prior to her role as Chief Information Officer, Ms. Simon held a variety of roles in finance and information technology with Conagra Brands since joining the company in 2000, including serving as VP Global Business Services from January 2016 to June 2017, and VP Information Technology from 2008 to 2016.
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	46	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	51	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 16, 2023, the last reported sale price of our ordinary shares as reported by the NYSE was $310.25 per share. We have approximately 409 holders of record of our class A ordinary shares as of February 16, 2023.

The following information relates to the repurchases of equity securities by Aon or any affiliated purchaser during each 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)
10/1/22 – 10/31/22	896,708	$	278.80	896,708	$	6,442,274,888
11/1/22 – 11/30/22	660,458	$	296.76	660,458	$	6,246,278,509
12/1/22 – 12/31/22	753,523	$	303.90	753,523	$	6,017,286,196
	2,310,689	$	292.12	2,310,689	$	6,017,286,196

(1)Does not include commissions 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 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 2022.

Item 6.    [Reserve]

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

EXECUTIVE SUMMARY OF 2022 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 2022 financial results:

•Revenue increased $286 million, or 2%, to $12.5 billion in 2022 compared to 2021, reflecting 6% organic revenue growth and a 1% favorable impact from fiduciary investment income, partially offset by a 4% unfavorable impact from foreign currency translation a 1% unfavorable impact from acquisitions, divestitures and other.

•Operating expenses decreased $1.3 billion, or 13%, to $8.8 billion in 2022 compared to 2021 due primarily to the $1.0 billion payment made in connection with terminating the combination with WTW (the “Termination Fee”) and certain transaction costs incurred related to the termination in the prior year (together, the “Transaction Costs”) and a $373 million favorable impact from foreign currency translation, partially offset by an increase in expense associated with 6% organic revenue growth, investments in long-term growth, and a $58 million charge related to certain legal settlements reached.

•Operating margin increased to 29.4% in 2022 from 17.1% in 2021. The increase was driven by a decrease in operating expenses as listed above and organic revenue growth of 6%.

•Due to the factors set forth above, Net income was $2.6 billion in 2022, an increase of $1.3 billion, or 102%, from 2021.

•Diluted earnings per share increased 119% to $12.14 per share during the twelve months of 2022 compared to $5.55 per share for the prior year period.

•Cash flows provided by operating activities was $3.2 billion in 2022, an increase of $1.0 billion, or 48%, from $2.2 billion in 2021, primarily due to the Transaction Costs paid in the prior year period, and strong operating income growth, partially offset by higher incentive compensation payments made in the current year following strong performance in 2021.

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 2022:

•Organic revenue growth, a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth,” was 6% in 2022, compared to 9% 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 30.8% in 2022, compared to 30.1% in the prior year. The increase in adjusted operating margin primarily reflects 6% organic revenue growth and a higher fiduciary investment income, partially offset by increased expenses and investments in long-term growth.

•Adjusted diluted earnings per share, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was $13.39 per share in 2022, an increase of $1.39 per share, or 12%, from $12.00 per share in 2021. The increase in adjusted diluted earnings per share primarily reflects strong operational performance and effective capital management, highlighted by $3.2 billion of share repurchase during 2022, partially offset by an unfavorable impact from foreign currency translation.

•Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was $3.0 billion in 2022, an increase of $978 million, or 48%, from $2.0 billion in 2021, reflecting an increase in Cash flows from operations, partially offset by a $59 million increase in capital expenditures.

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ENVIRONMENTAL, SOCIAL, AND GOVERNANCE

For many companies, the management of ESG risks and opportunities has become increasingly important, and ESG-related challenges, such as extreme weather events, supply chain disruptions, cyber events, regulatory changes, ongoing public health impacts, and the increased focus on workforce resilience in highly varied work environments continue to create volatility and uncertainty for our clients. Aon offers a wide range of risk assessment, consulting and advisory solutions, many of which are significant parts of our core business offerings, designed to address and manage ESG issues for clients, and to enable our clients to create more sustainable value. We view ESG risks as presenting an important opportunity for Aon to work together as one firm to address client needs 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
	2022		2021		2020
Revenue
Total revenue	$	12,479	$	12,193	$	11,066
Expenses
Compensation and benefits	6,477		6,738		5,905
Information technology	509		477		444
Premises	289		327		291
Depreciation of fixed assets	151		179		167
Amortization and impairment of intangible assets	113		147		246
Other general expense	1,271		2,235		1,232
Total operating expenses	8,810		10,103		8,285
Operating income	3,669		2,090		2,781
Interest income	18		11		6
Interest expense	(406)		(322)		(334)
Other income (expense)	(125)		152		13
Income before income taxes	3,156		1,931		2,466
Income tax expense	510		623		448
Net income	2,646		1,308		2,018
Less: Net income attributable to noncontrolling interests	57		53		49
Net income attributable to Aon shareholders	$	2,589	$	1,255	$	1,969
Diluted net income per share attributable to Aon shareholders	$	12.14	$	5.55	$	8.45
Weighted average ordinary shares outstanding - diluted	213.2		226.1		233.1

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Consolidated Results for 2022 Compared to 2021

Revenue

Total revenue increased $286 million, or 2%, to $12.5 billion in 2022, compared to $12.2 billion in 2021. The increase was driven by 6% organic revenue growth and a 1% favorable impact from fiduciary investment income, partially offset by a 4% unfavorable impact from foreign currency translation and a 1% unfavorable impact from acquisitions, divestitures, and other.

Commercial Risk Solutions revenue increased $80 million, or 1%, to $6.7 billion in 2022, compared to $6.6 billion in 2021. Organic revenue growth was 6% in 2022, reflecting growth across every major geography, including double-digit growth in Latin America, Asia, and the Pacific, driven by strong net new business generation, retention, and management of the renewal book portfolio. U.S. retail brokerage was pressured primarily by Transaction Solutions, which declined due to lower external deal volume. Results also reflect strong growth globally in the affinity business across both consumer and business solutions, including growth in the travel and events practice and Digital Client Solutions. On average globally, exposures and pricing were modestly positive, resulting in modestly positive market impact.

Reinsurance Solutions revenue increased $193 million, or 10%, to $2.2 billion in 2022, compared to $2.0 billion in 2021. Organic revenue growth was 8% in 2022 driven by strong net new business generation in treaty, as well as solid growth in facultative placements and the Strategy and Technology Group. In addition, market impact was modestly positive on results.

Health Solutions revenue increased $70 million, or 3%, to $2.2 billion in 2022, compared to $2.2 billion in 2021. Organic revenue growth was 8% in 2022, reflecting growth globally in core health and benefits brokerage, driven by strong retention, net new business generation and management of the renewal book portfolio. Strength in health and benefits included growth in advisory work related to wellbeing and resilience. Results also reflect double-digit growth in Human Capital, driven by data and advisory solutions, and modest growth in Consumer Benefits Solutions.

Wealth Solutions revenue decreased $59 million, or 4%, to $1.4 billion in 2022, compared to $1.4 billion in 2021. The decrease was primarily driven by a 5% unfavorable impact from foreign currency translation and a 2% unfavorable impact from acquisitions, divestitures, and other. This decrease was offset by organic revenue growth of 3% in 2022 driven by high demand and project related work related to pension risk transfer and ongoing impacts of regulatory changes. In Investments, a decrease in AUM-based delegated investment management revenue due to equity market and interest rate movements was partially offset by higher advisory demand and project-related work.

Compensation and Benefits

Compensation and benefits decreased $261 million, or 4%, in 2022 compared to 2021. The decrease was primarily driven by a $293 million favorable impact from foreign currency translation and a $245 million decrease in Transaction Costs, partially offset by an increase in expense associated with 6% organic revenue growth.

Information Technology

Information technology, which represents costs associated with supporting and maintaining our infrastructure, increased $32 million, or 7%, in 2022 compared to 2021. The increase was primarily driven by ongoing investments in Aon Business Services-enabled technology platforms and technology to drive long-term growth, partially offset by a $17 million decrease in Transaction Costs.

Premises

Premises, which represents the cost of occupying offices in various locations throughout the world, decreased $38 million, or 12%, in 2022 compared to 2021. The decrease was primarily driven by a $22 million decrease in Transaction Costs and a $19 million favorable 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 decreased $28 million, or 16%, in 2022 compared to 2021. The decrease was primarily driven by a $16 million decrease in Transaction Costs.

Amortization and Impairment of Intangible Assets

Amortization and impairment of intangibles primarily relates to finite-lived customer-related and contract-based, technology, and tradename assets. Amortization and impairment of intangibles decreased $34 million, or 23%, in 2022 compared to 2021.

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Other General Expenses

Other general expenses decreased $964 million, or 43%, in 2022 compared to 2021. The decrease was primarily driven by a $1.1 billion decrease in Transaction Costs, partially offset by an increase in expense associated with 6% organic revenue growth, including travel and entertainment expense, and a $58 million charge from certain legal settlements reach in 2022.

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 $18 million in 2022, an increase of $7 million, or 64%, from 2021.

Interest Expense

Interest expense, which represents the cost of our debt obligations, was $406 million in 2022, an increase of $84 million, or 26%, from 2021. The increase primarily reflects an increase in total debt.

Other Income (Expense)

Other expense was $125 million in 2022, which primarily reflects a non-cash pension settlement charge of $170 million incurred in the fourth quarter, compared to Other income of $152 million in 2021, primarily reflecting a gain from sale of businesses in the prior year period.

Income before Income Taxes

Income before income taxes was $3.2 billion in 2022, a 63% increase from $1.9 billion in 2021. The increase was primarily driven by $1.4 billion in Transaction Costs in the prior year period and strong operational performance.

Income Taxes

The effective tax rate on net income was 16.2% in 2022 and 32.3% in 2021. The 2022 tax rate was primarily driven by the geographical distribution of income and certain discrete items, primarily the favorable impacts of share-based payments.

The 2021 tax rate was primarily driven by 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.

Net Income Attributable to Aon Shareholders

Net income attributable to Aon shareholders increased to $2.6 billion, or $12.14 per diluted share, in 2022, compared to $1.3 billion, or $5.55 per diluted share, in 2021.

Consolidated Results for 2021 Compared to 2020

We have elected not to include a discussion of our consolidated results for 2021 compared to 2020 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, 2021, which was filed with the SEC on February 18, 2022.

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, adjusted operating margin, adjusted diluted earnings per share, adjusted net income attributable to Aon shareholders, adjusted net income per share, other income (expense), as adjusted, adjusted effective tax rate, 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

We use supplemental information related to organic revenue growth to help us and our investors evaluate business growth from existing operations. Organic revenue growth is a non-GAAP measure that includes the impact of certain 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 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, 2022		Dec 31, 2021		% Change		Less: Currency Impact (1)		Less: Fiduciary Investment Income (2)		Less: Acquisitions, Divestitures & Other		Organic Revenue Growth (3)
Commercial Risk Solutions	$	6,715	$	6,635	1	%	(4)	%	1	%	(2)	%	6	%
Reinsurance Solutions	2,190		1,997		10		(3)		1		4		8
Health Solutions	2,224		2,154		3		(3)		—		(2)		8
Wealth Solutions	1,367		1,426		(4)		(5)		—		(2)		3
Elimination	(17)		(19)		N/A		N/A		N/A		N/A		N/A
Total revenue	$	12,479	$	12,193	2	%	(4)	%	1	%	(1)	%	6	%

	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)		NA		NA		NA		NA		NA
Total revenue	$	12,193	$	11,066	10	%	2	%	—	%	(1)	%	9	%

(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, 2022 2021, and 2020 was $76 million, $8 million, and $27 million, respectively.

(3)Organic revenue growth includes the impact of certain 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
	2022			2021
Revenue	$	12,479		$	12,193
Operating income - as reported	$	3,669		$	2,090
Amortization and impairment of intangible assets	113			147
Transaction costs and other charges related to the combination and resulting termination (1)	—			1,436
Legal settlements (2)	$	58		$	—
Operating income - as adjusted	3,840			3,673
Operating margin - as reported	29.4		%	17.1		%
Operating margin - as adjusted	30.8		%	30.1		%

(1)As part of the terminated combination with WTW, certain transaction costs were incurred by the Company through the third quarter of 2021. These costs included advisory, legal, accounting, valuation, and other professional or consulting fees related to the combination, including planned divestitures, some of which were 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.

(2)In connection with certain legal settlements reached, a $58 million charge was recognized in the second quarter of 2022.

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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 impact of certain items, as listed below, because management does not believe these expenses are the best indicators of our core operating performance. 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, 2022
	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income	$	3,669		$	171	$	3,840
Interest income	18			—		18
Interest expense	(406)			—		(406)
Other income (expense) (1)	(125)			170		45
Income before income taxes	3,156			341		3,497
Income tax expense (2)	510			75		585
Net income	2,646			266		2,912
Less: Net income attributable to noncontrolling interests	57			—		57
Net income attributable to Aon shareholders	$	2,589		$	266	$	2,855
Diluted net income per share attributable to Aon shareholders	$	12.14		$	1.25	$	13.39
Weighted average ordinary shares outstanding — diluted	213.2			—		213.2
Effective tax rates (2)	16.2		%			16.7		%

	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 (expense) (3)	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		%

(1)To further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. A non-cash settlement charge totaling $170 million was recognized in the fourth quarter of 2022 which is excluded from Adjusted Other income (expense).

(2)Adjusted items are generally taxed at the estimated annual effective tax rate, except for the applicable tax impact associated with certain transaction costs and other charges related to the combination and resulting termination, as well as certain legal and pension settlements, 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)Adjusted Other income (expense) excludes gains from dispositions of $124 million, for the year ended December 31, 2021.

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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
	2022		2021
Cash provided by operating activities	$	3,219	$	2,182
Capital expenditures	(196)		(137)
Free cash flow	$	3,023	$	2,045

Impact of Foreign Currency Exchange Rate Fluctuations

Because we conduct business in more than 120 countries and sovereignties, 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 an unfavorable impact of $0.33 on earnings per diluted share during the year ended December 31, 2022 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had a favorable impact of $0.17 on earnings per diluted share during the year ended December 31, 2021, if 2020 results were translated at 2021 rates.

Currency fluctuations had an unfavorable impact of $0.44 on adjusted earnings per diluted share during the year ended December 31, 2022 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had a favorable impact of $0.23 on adjusted earnings per diluted share during the year ended December 31, 2021, if 2020 results were translated at 2021 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.

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

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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 $6.4 billion and $6.1 billion at December 31, 2022 and 2021, and fiduciary receivables of $9.5 billion and $8.3 billion at December 31, 2022 and 2021, 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, 2022, 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, 2022 (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	$	690	$	—	$	3,515	$	4,205
Money market funds	—		452		2,871		3,323
Cash, Short-term investments, and funds held on behalf of clients	690		452		6,386		7,528
Fiduciary receivables	—		—		9,514		9,514
Total	$	690	$	452	$	15,900	$	17,042

Cash and cash equivalents and funds held on behalf of clients increased $431 million in 2022 compared to 2021. 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
	2022		2021
Cash provided by operating activities	$	3,219	$	2,182
Cash provided by (used for) investing activities	$	(449)	$	49
Cash used for financing activities	$	(1,790)	$	(1,924)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	$	(549)	$	(235)

Operating Activities

Net cash provided by operating activities during the year ended December 31, 2022 increased $1,037 million, or 48%, from the prior year to $3,219 million. This amount represents Net income reported, generally adjusted for the following primary drivers including gains from sales of businesses, losses from sales of businesses, share-based compensation expense, depreciation expense, amortization and impairments, and other non-cash income and expenses, including pension settlement charges. Adjustments also include changes in working capital that relate primarily to the timing of payments of accounts payable and accrued liabilities and collection of receivables.

Pension Contributions

Pension contributions were $59 million for the year ended December 31, 2022, as compared to $87 million for the year ended December 31, 2021. In 2023, we expect to contribute approximately $61 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 used for investing activities during the year ended December 31, 2022 were $449 million, a decrease of $498 million compared to prior year. 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. Generally, the primary drivers of cash flows provided by investing activities are sales of businesses, sales of short-term investments, and proceeds from 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 (expense) in the Consolidated Statements of Income.

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Short-term Investments

Short-term investments increased $160 million at December 31, 2022 as compared to December 31, 2021. 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 2022, the Company completed the acquisition of five businesses for consideration of $162 million, net of cash and funds held on behalf of clients, and the disposition of three businesses for a $81 million cash inflow, net of cash and funds held on behalf of clients.

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 business for a $218 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 $196 million in 2022 and $137 million in 2021, primarily related to refurbishing and modernizing of office facilities, software development costs, and computer equipment purchases.

Financing Activities

Cash flows used for financing activities during the year ended December 31, 2022 was $1,790 million, a decrease of $134 million compared to prior year. Generally, the primary drivers of cash flow used for financing activities are repayments of debt, share repurchases, dividends paid to shareholders, cash paid for employee taxes on withholding shares, 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. Generally, the primary drivers of cash flow provided by financing activities are issuances of debt, changes in net fiduciary liabilities, and proceeds from issuance of shares.

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 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
	2022		2021
Shares repurchased	11.1		12.4
Average price per share	$	289.76	$	286.82
Repurchase costs recorded to accumulated deficit	$	3,203	$	3,543

At December 31, 2022, the remaining authorized amount for share repurchase under the Repurchase Program was approximately $6.0 billion. Under the Repurchase Program, we have repurchased a total of 160.7 million shares for an aggregate cost of approximately $21.5 billion.

Borrowings

Total debt at December 31, 2022 was $10.8 billion, an increase of $1.4 billion compared to December 31, 2021.

In November 2022, Aon Global Limited’s $350 million 4.00% Senior Notes due November 2023 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2022.

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In November 2022, Aon Corporation’s $500 million 2.20% Senior Notes matured and were repaid in full. 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.

On September 12, 2022, 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 $500 million of 5.00% Senior Notes due September 2032. The Company intends to use the net proceeds from the offering for general corporate purposes.

On February 28, 2022, Aon Corporation and Aon Global Holdings plc co-issued $600 million of 2.85% Senior Notes due May 2027 and $900 million of 3.90% Senior Notes due February 2052. The Company intends to use the net proceeds from the offering for general corporate purposes.

On December 2, 2021, Aon Corporation and Aon Global Holdings plc co-issued $500 million aggregate principal amount of 2.60% Senior Notes due December 2031. We intend to use the net proceeds of the offering for general corporate purposes.

On August 23, 2021, Aon Corporation and Aon Global Holdings plc 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 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. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

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 our committed credit facilities, which was approximately $1.8 billion at December 31, 2022. The aggregate capacity of the Commercial Paper Program remains fully backed by our committed credit facilities. Commercial paper activity during the years ended December 31, 2022 and 2021 is as follows (in millions):

	Years Ended December 31
	2022		2021 (2)
Total issuances (1)	$	12,301	$	4,478
Total repayments	(12,366)		(3,807)
Net issuances (repayments)	$	(65)	$	671

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

(2) 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.

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. Accumulated deficit). As of December 31, 2022 and December 31, 2021, we had distributable profits in excess of $29.0 billion and $32.7 billion, respectively. We believe that we will have sufficient distributable profits for the foreseeable future.

Credit Facilities

We expect cash generated by operations for 2022 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.

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As of December 31, 2022, 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 2024. In aggregate, these two facilities provide approximately $1.8 billion in available credit.

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, 2022, 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, 2022.

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.

Rating Agency Ratings

The major rating agencies’ ratings of our debt at February 17, 2023 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

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 a LOC. We had total LOCs outstanding of approximately $74 million at December 31, 2022, compared to $75 million at December 31, 2021. 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 $173 million at December 31, 2022, compared to $153 million at December 31, 2021.

Contractual Obligations

Our contractual obligations and commitments as of December 31, 2022 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 Ireland Reorganization, 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 Ireland 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

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 May 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 Ireland 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

2.85% Senior Notes due May 2027

2.05% Senior Notes due August 2031

2.60% Senior Notes due December 2031

5.00% Senior Notes due September 2032

2.90% Senior Notes due August 2051

3.90% Senior Notes due February 2052

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, 2022
Revenue	$	—
Operating loss	$	(102)
Expense from non-guarantor subsidiaries before income taxes	$	(656)
Net loss	$	(1,069)
Net loss attributable to Aon shareholders	$	(1,069)

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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, 2022
Receivables due from non-guarantor subsidiaries	$	1,300
Other current assets	317
Total current assets	$	1,617
Non-current receivables due from non-guarantor subsidiaries	$	483
Other non-current assets	1,060
Total non-current assets	$	1,543
Payables to non-guarantor subsidiaries	$	16,172
Other current liabilities	5,880
Total current liabilities	$	22,052
Non-current payables to non-guarantor subsidiaries	$	2,343
Other non-current liabilities	11,226
Total non-current liabilities	$	13,569

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 delivered 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. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. 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, Strategy and Technology Group, 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 for treaty reinsurance arrangements, over the term of the arrangement in installments based on deposit or minimum premiums.

Health Solutions includes consulting and brokerage, Human Capital, and Consumer Benefits 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 Consumer Benefits 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. Revenue generated from our delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. 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 (expense). 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, 2022, 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 2023 amortization of loss by country (in millions, except amortization period):

	U.K.		U.S.		Other
Accumulated other comprehensive loss	$	1,761	$	1,305	$	437
Amortization period	7 to 25 years		6 to 23 years		11 to 34 years
Estimated 2023 amortization of loss	$	74	$	34	$	13

The U.S. had no unrecognized prior service cost (credit) at December 31, 2022. The unrecognized prior service cost (credit) at December 31, 2022 was $35 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, 2022, the market-related value of assets was $1.8 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, 2022, the fair value of plan assets was $1.5 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, 2022:

	U.K.	U.S.	Other
Expected return on plan assets, net of administration expenses	5.34%	6.82%	4.20 - 4.85%

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, 2022 (in millions):

Increase (decrease) in projected benefit obligation (1)	25 BPS Change in Discount Rate
	Increase		Decrease
U.K. plans	$	(95)	$	(98)
U.S. plans	$	(53)	$	56
Other plans	$	(39)	$	41

(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 2023 pension expense (in millions):

	25 BPS Change in Discount Rate
Increase (decrease) in expense	Increase		Decrease
U.K. plans	$	(3)	$	3
U.S. plans	$	—	$	—
Other plans	$	—	$	—

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 2023 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	$	(9)	$	9
U.S. plans	$	(4)	$	4
Other plans	$	(3)	$	3

Estimated Future Contributions

We estimate cash contributions of approximately $61 million to our pension plans in 2023 as compared with cash contributions of $59 million in 2022.

Goodwill and Other Intangible Assets

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

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 significant 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 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. We aggregate components of any operating segments that have similar economic characteristics into a single reporting unit.

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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.

When 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 an asset group’s carrying value 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 all contingencies are resolved.

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, 2022, 2021, or 2020. 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.

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 2020 to 2022 performance period ended on December 31, 2022, the 2019 to 2021 performance period ended on December 31, 2021, and the 2018 to 2020 performance period ended on December 31, 2020. The LPP currently has two open performance periods: 2021 to

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2023 and 2022 to 2024. A 10% upward adjustment in our estimated performance achievement percentage for both open performance periods would have increased our 2022 expense by approximately $2.6 million, while a 10% downward adjustment would have decreased our expense by approximately $7.7 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, 2022, 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, 2023 and 2024. 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.

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 $19 million and $9 million at December 31, 2023 and 2024, respectively.

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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 an unfavorable $0.33 impact during the year ended December 31, 2022. 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 an unfavorable $0.44 impact during the year ended December 31, 2022 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 $67 million to each of 2023 and 2024 pretax income. A corresponding increase in the year-end yield curve of 100 BPS would cause an increase, net of derivative positions, of $67 million to each of 2023 and 2024 pre-tax income.

We have long-term debt outstanding, excluding the current portion, with a fair market value of $8.7 billion and $9.2 billion as of December 31, 2022 and December 31, 2021, respectively. The fair value was less than the carrying value by $1.1 billion at December 31, 2022, and $0.9 billion greater than the carrying value at December 31, 2021. A hypothetical 1% increase or decrease in interest rates would change the fair value by a decrease of 7% or an increase of 8%, respectively, at December 31, 2022.

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 the Board of Directors of Aon plc

Opinion on the Financial Statements

We have audited the accompanying consolidated statements of financial position of Aon plc (the Company) as of December 31, 2022 and 2021, the related consolidated statements of income, comprehensive income, shareholders’ equity (deficit) and cash flows for each of the three years in the period ended December 31, 2022, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2022 and 2021, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2022, 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, 2022, 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 17, 2023, 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 9 “Income Taxes” of the Notes to Consolidated Financial Statements, the Company had net deferred tax assets of $725 million at December 31, 2022. 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, timing, and jurisdiction 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 of future taxable income.
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 the amount, timing, and jurisdiction 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 assumptions made in the calculation of future taxable income, including the growth rate, the estimates of the reversal of cumulative temporary differences, and the capital and debt requirements by jurisdiction. We compared the projections of future taxable income with the actual results of prior periods. 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 17, 2023

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Aon plc

Consolidated Statements of Income

	Years Ended December 31
(millions, except per share data)	2022		2021		2020
Revenue
Total revenue	$	12,479	$	12,193	$	11,066
Expenses
Compensation and benefits	6,477		6,738		5,905
Information technology	509		477		444
Premises	289		327		291
Depreciation of fixed assets	151		179		167
Amortization and impairment of intangible assets	113		147		246
Other general expense	1,271		2,235		1,232
Total operating expenses	8,810		10,103		8,285
Operating income	3,669		2,090		2,781
Interest income	18		11		6
Interest expense	(406)		(322)		(334)
Other income (expense)	(125)		152		13
Income before income taxes	3,156		1,931		2,466
Income tax expense	510		623		448
Net income	2,646		1,308		2,018
Less: Net income attributable to noncontrolling interests	57		53		49
Net income attributable to Aon shareholders	$	2,589	$	1,255	$	1,969
Basic net income per share attributable to Aon shareholders	$	12.23	$	5.59	$	8.49
Diluted net income per share attributable to Aon shareholders	$	12.14	$	5.55	$	8.45
Weighted average ordinary shares outstanding - basic	211.7		224.7		231.9
Weighted average ordinary shares outstanding - diluted	213.2		226.1		233.1

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Comprehensive Income

	Years Ended December 31
(millions)	2022		2021		2020
Net income	$	2,646	$	1,308	$	2,018
Less: Net income attributable to noncontrolling interests	57		53		49
Net income attributable to Aon shareholders	2,589		1,255		1,969
Other comprehensive income (loss), net of tax:
Change in fair value of financial instruments	(13)		1		13
Foreign currency translation adjustments	(528)		(289)		263
Postretirement benefit obligation	(211)		277		(101)
Total other comprehensive income (loss)	(752)		(11)		175
Less: Other comprehensive income (loss) attributable to noncontrolling interests	—		(1)		3
Total other comprehensive income (loss) attributable to Aon shareholders	(752)		(10)		172
Comprehensive income attributable to Aon shareholders	$	1,837	$	1,245	$	2,141

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)	2022		2021
Assets
Current assets
Cash and cash equivalents	$	690	$	544
Short-term investments	452		292
Receivables, net	3,035		3,094
Fiduciary assets	15,900		14,386
Other current assets	646		716
Total current assets	20,723		19,032
Goodwill	8,292		8,434
Intangible assets, net	447		492
Fixed assets, net	558		529
Operating lease right-of-use assets	699		786
Deferred tax assets	824		766
Prepaid pension	652		1,366
Other non-current assets	509		512
Total assets	$	32,704	$	31,917
Liabilities and equity (deficit)
Liabilities
Current liabilities
Accounts payable and accrued liabilities	$	2,114	$	2,192
Short-term debt and current portion of long-term debt	945		1,164
Fiduciary liabilities	15,900		14,386
Other current liabilities	1,347		1,331
Total current liabilities	20,306		19,073
Long-term debt	9,825		8,228
Non-current operating lease liabilities	693		772
Deferred tax liabilities	99		401
Pension, other postretirement, and postemployment liabilities	1,186		1,375
Other non-current liabilities	1,024		910
Total liabilities	33,133		30,759
Equity (deficit)
Ordinary shares - $0.01 nominal value     Authorized: 500.0 shares (issued: 2022 - 205.4; 2021 - 214.8)	2		2
Additional paid-in capital	6,864		6,624
Accumulated deficit	(2,772)		(1,694)
Accumulated other comprehensive loss	(4,623)		(3,871)
Total Aon shareholders' equity (deficit)	(529)		1,061
Noncontrolling interests	100		97
Total equity (deficit)	(429)		1,158
Total liabilities and equity (deficit)	$	32,704	$	31,917

See accompanying Notes to Consolidated Financial Statements.

55

Aon plc

Consolidated Statements of Shareholders’ Equity (Deficit)

(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 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 repurchased	(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 repurchased	(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
Net income	—	—		2,589		—		57		2,646
Shares issued — employee stock compensation plans	1.7	(156)		(1)		—		—		(157)
Shares repurchased	(11.1)	—		(3,203)		—		—		(3,203)
Share-based compensation expense	—	397		—		—		—		397
Dividends to shareholders ($2.19 per share)	—	—		(463)		—		—		(463)
Net change in fair value of financial instruments	—	—		—		(13)		—		(13)
Net foreign currency translation adjustments	—	—		—		(528)		—		(528)
Net postretirement benefit obligation	—	—		—		(211)		—		(211)
Net purchases of shares from noncontrolling interests	—	(1)		—		—		(1)		(2)
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(53)		(53)
Balance at December 31, 2022	205.4	$	6,866	$	(2,772)	$	(4,623)	$	100	$	(429)

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Cash Flows

	Years Ended December 31
(millions)	2022		2021		2020
Cash flows from operating activities
Net income	$	2,646	$	1,308	$	2,018
Adjustments to reconcile net income to cash provided by operating activities:
Gain from sales of businesses	(54)		(142)		(25)
Depreciation of fixed assets	151		179		167
Amortization and impairment of intangible assets	113		147		246
Share-based compensation expense	397		449		312
Deferred income taxes	(252)		11		9
Other, net	170		5		2
Change in assets and liabilities:
Receivables, net	(96)		(119)		108
Accounts payable and accrued liabilities	(22)		264		186
Current income taxes	216		200		(17)
Pension, other postretirement and postemployment liabilities	(53)		(124)		(143)
Other assets and liabilities	3		4		(80)
Cash provided by operating activities	3,219		2,182		2,783
Cash flows from investing activities
Proceeds from investments	110		58		64
Payments for investments	(107)		(91)		(97)
Net sales (purchases) of short-term investments - non fiduciary	(175)		15		(167)
Acquisition of businesses, net of cash and funds held on behalf of clients	(162)		(14)		(368)
Sale of businesses, net of cash and funds held on behalf of clients	81		218		30
Capital expenditures	(196)		(137)		(141)
Cash provided by (used for) investing activities	(449)		49		(679)
Cash flows from financing activities
Share repurchase	(3,203)		(3,543)		(1,763)
Proceeds from issuance of shares	58		55		44
Cash paid for employee taxes on withholding shares	(215)		(185)		(193)
Commercial paper issuances, net of repayments	(65)		671		(113)
Issuance of debt	1,967		1,495		991
Repayment of debt	(500)		(413)		(607)
Increase in fiduciary liabilities, net of fiduciary receivables	702		568		316
Cash dividends to shareholders	(463)		(447)		(412)
Noncontrolling interests and other financing activities	(71)		(125)		(35)
Cash used for financing activities	(1,790)		(1,924)		(1,772)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(549)		(235)		297
Net increase in cash and cash equivalents and funds held on behalf of clients	431		72		629
Cash and cash equivalents and funds held on behalf of clients at beginning of year	6,645		6,573		5,944
Cash and cash equivalents and funds held on behalf of clients at end of year	$	7,076	$	6,645	$	6,573
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	$	690	$	544	$	884
Funds held on behalf of clients	6,386		6,101		5,689
Total cash and cash equivalents and funds held on behalf of clients	$	7,076	$	6,645	$	6,573
Supplemental disclosures:
Interest paid	$	351	$	328	$	326
Income taxes paid, net of refunds	$	546	$	412	$	455

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 and Notes thereto 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.

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, and foreign currency exchange rate movements 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.

Reclassification

Certain amounts in prior periods' Consolidated Financial Statements have been reclassified to conform to the current year presentation. In prior periods, commercial paper issuances and repayments were included in Issuance of debt and Repayment of debt, respectively, in the Consolidated Statements of Cash Flows. The net amount of commercial paper activity is now disclosed separately in Commercial paper issuances, net of repayments in the Consolidated Statements of Cash Flows. For the year ended December 31, 2021 and December 31, 2020, commercial paper issuances reclassified from Issuance of debt was $4,478 million and $3,162 million, respectively, and commercial paper repayments reclassified from Repayment of debt was $3,807 million and $3,275 million, respectively. Further information on the gross commercial paper activity for the current and prior year periods is included within the Liquidity and Financial Conditions section of Part II Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

In November 2022, Aon incurred a non-cash pension settlement charge of $170 million in connection with the purchase of an annuity for portions of its U.S. pension plans. Aon has separately classified the non-cash pension settlement charge within Other, net on the Consolidated Statement of Cash Flows as an adjustment to reconcile Net income to Cash provided by operating activities for the period ended December 31, 2022. Prior year comparable balances have been reclassified to conform with current year presentation. For the years ended December 31, 2021 and 2020, Aon incurred insignificant non-cash pension settlement charges of $5 million and $2 million, respectively, which were presented as changes in assets and liabilities held within Pension, other postretirement and other postemployment liabilities in the Consolidated Statements of Cash Flows. See Note 11 “Employee Benefits” for further information regarding the non-cash settlement charges incurred.

In prior periods, Cash paid for employee taxes on withholding shares were included with Proceeds from issuance of shares, and presented as Issuance of shares for employee benefit plans in the Consolidated Statements of Cash Flows. These items are now presented separately and prior year balances have been reclassified to conform to current year presentation. For the year ended December 31, 2021 and December 31, 2020, Proceeds from issuance of shares was $55 million and $44 million, respectively, and Cash paid for employee taxes on withholding shares was $185 million and $193 million, respectively.

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 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. The customer

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obtains control over the services promised by the Company at the completion of the insurance or reinsurance policy placement process once coverage is effective. 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 delivered 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. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. 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, Strategy and Technology Group, 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 Consumer Benefits 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.

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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. Revenue generated from the Company’s delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. 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, 2022, 2021, or 2020. 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 (expense) 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 generally 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, 2022, Cash and cash equivalents and Short-term investments totaled $1,142 million compared to $836 million at December 31, 2021, an increase of $306 million. Of the total balance, $115 million and $160 million was restricted as to its use at December 31, 2022 and 2021, respectively. Included within Short-term investments as of December 31, 2022 and 2021 balances, respectively, were £60.1 million ($72.5 million at December 31, 2022 exchanges rates) and £84.3 million ($112.8 million at December 31, 2021 exchange rates) of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator.

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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 $6.4 billion and $6.1 billion at December 31, 2022 and 2021, respectively. Fiduciary receivables were $9.5 billion and $8.3 billion at December 31, 2022 and 2021, 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 $76 million and $90 million at December 31, 2022 and 2021, 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 purchase price 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 relative 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 the 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 customer-related and contract based, technology, tradenames, or other intangibles. 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 (expense) 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.

The Company releases income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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’s lease agreements may include initial direct costs and lease incentives. Initial direct costs are incremental costs of a lease that would not have been incurred if the lease had not been obtained and are included in the measurement of the ROU asset. Payments made to or on behalf of the Company, such as tenant improvement allowances, represent incentives that are considered reductions to the ROU asset and lease expense over the lease term.

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 applies 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.

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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 variable interest model to the entity, otherwise, the entity is evaluated under the voting interest model. When 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 hold a controlling financial interest over any VIEs that significantly impacts the VIE’s economic performance and the Company does not have rights to any significant benefits or obligations to absorb potentially significant losses. Thus, the Company does not consolidate any VIEs and Aon’s interest in VIEs as of December 31, 2022 was insignificant.

Aon holds a controlling financial interest in entities that are not VIEs when it, directly or indirectly holds more than 50% of the voting rights and the noncontrolling interest holders do not hold substantive participating rights.

New Accounting Pronouncements

All issued, but not yet effective, guidance has been deemed not applicable or not significant to 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):

	Years Ended December 31
	2022		2021		2020
Commercial Risk Solutions	$	6,715	$	6,635	$	5,861
Reinsurance Solutions	2,190		1,997		1,814
Health Solutions	2,224		2,154		2,067
Wealth Solutions	1,367		1,426		1,341
Elimination	(17)		(19)		(17)
Total revenue	$	12,479	$	12,193	$	11,066

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
	2022		2021		2020
U.S.	$	5,666	$	5,459	$	5,032
Americas other than U.S.	1,137		1,027		911
U.K.	1,660		1,681		1,579
Ireland	99		127		84
Europe, Middle East, & Africa other than U.K. and Ireland	2,443		2,565		2,236
Asia Pacific	1,474		1,334		1,224
Total revenue	$	12,479	$	12,193	$	11,066

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Contract Costs

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

	2022		2021
Balance at beginning of period	$	361	$	339
Additions	1,479		1,504
Amortization	(1,480)		(1,478)
Impairment	—		—
Foreign currency translation and other	(5)		(4)
Balance at end of period	$	355	$	361

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

	2022		2021
Balance at beginning of period	$	179	$	184
Additions	56		59
Amortization	(49)		(48)
Impairment	—		—
Foreign currency translation and other	(1)		(16)
Balance at end of period	$	185	$	179

4.    Other Financial Data

Consolidated Statements of Income Information

Other Income (Expense)

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

	Years Ended December 31
	2022		2021		2020
Pension and other postretirement (1)	$	(179)	$	21	$	13
Foreign currency remeasurement	(14)		26		(12)
Extinguishment of debt	—		—		(7)
Financial instruments and other	4		(45)		(10)
Equity earnings	10		8		4
Gain from disposals of business	54		142		25
Total	$	(125)	$	152	$	13

(1) Refer to Note 11 “Employee Benefits” for further information.

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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):

	2022		2021		2020
Balance at beginning of period	$	90	$	98	$	77
Provision	8		26		29
Accounts written off, net of recoveries	(18)		(37)		(6)
Foreign currency translation and other	(4)		3		(2)
Balance at end of period	$	76	$	90	$	98

Other Current Assets

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

As of December 31	2022		2021
Costs to fulfill contracts with customers (1)	$	355	$	361
Prepaid expenses	109		137
Taxes receivable	74		53
Other	108		165
Total	$	646	$	716

(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	2022		2021
Software	$	861	$	797
Leasehold improvements	409		425
Computer equipment	269		268
Furniture, fixtures, and equipment	267		279
Construction in progress	109		45
Other	34		33
Fixed assets, gross	1,949		1,847
Less: Accumulated depreciation	1,391		1,318
Fixed assets, net	$	558	$	529

Depreciation expense, which includes software amortization, was $151 million, $179 million, and $167 million for the years ended December 31, 2022, 2021, and 2020, 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	2022		2021
Costs to obtain contracts with customers (1)	$	185	$	179
Taxes receivable	109		95
Investments	60		64
Leases (2)	43		63
Other	112		111
Total	$	509	$	512

(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	2022		2021
Deferred revenue (1)	$	250	$	321
Taxes payable	193		149
Leases (2)	186		213
Other	718		648
Total	$	1,347	$	1,331

(1)$653 million and $553 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2022 and December 31, 2021, 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	2022		2021
Taxes payable (1)	$	795	$	609
Compensation and benefits	69		58
Deferred revenue	37		70
Leases (2)	28		46
Other	95		127
Total	$	1,024	$	910

(1)Includes $129 million and $145 million for the non-current portion of the transition tax as of December 31, 2022 and December 31, 2021, respectively. 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 five acquisitions during the year ended December 31, 2022 and two acquisitions during the year ended December 31, 2021. 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, 2022
Consideration transferred
Cash	$	161
Deferred and contingent consideration	9
Aggregate consideration transferred	$	170
Assets acquired
Goodwill	$	87
Intangible assets	78
Other assets (1)	25
Total assets acquired	190
Liabilities assumed
Total liabilities assumed	20
Net assets acquired	$	170

(1)     Includes Cash and cash equivalents of $2 million and funds held on behalf of clients of an insignificant amount.

Intangible assets acquired include technology as well as customer-related and contract-based assets. The intangible assets acquired as part of business acquisitions in 2022 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, 2022 were insignificant. Total revenue for these acquisitions included in the Company’s Consolidated Statement of Income for the year ended December 31, 2022 was approximately $25 million.

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.

2022 Acquisitions

On November 1, 2022, the Company completed the acquisition of 100% of the share capital of E.R.N. Evaluacion de Riesgos Naturales y Antropogenicos, S.A. de C.V., a Mexico-based firm in risk assessment modeling.

On September 12, 2022, the Company completed the purchase of certain assets of Praxiom Risk Management, a provider of professional risk management in the U.S.

On August 1, 2022, the Company completed the purchase of certain assets of U.S. Advisors, Inc., a broker based in the U.S.

On May 3, 2022, the Company completed the acquisition of 100% of the share capital of Karl Köllner group companies, a marine hull broker based in Germany.

On March 1, 2022, the Company completed the acquisition of Tyche, an actuarial software platform based in the U.K.

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.

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Completed Dispositions

The Company completed three dispositions during the year ended December 31, 2022. The Company completed six dispositions during the year ended December 31, 2021 and one disposition during the year ended December 31, 2020.

The pretax gains recognized related to dispositions were $54 million, $142 million, and $25 million for the years ended December 31, 2022, December 31, 2021 and December 31, 2020, 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 dispositions were insignificant for the years ended December 31, 2022, December 31, 2021, and December 31, 2020, respectively.

6.    Goodwill and Other Intangible Assets

The changes in the net carrying amount of goodwill for the years ended December 31, 2022 and 2021, respectively, are as follows (in millions):

Balance as of January 1, 2021	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to current year disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434
Goodwill related to current year acquisitions	87
Goodwill related to current year disposals	(11)
Foreign currency translation and other	(218)
Balance as of December 31, 2022	$	8,292

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

As of December 31	2022						2021
	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	$	2,207	$	1,833	$	374	$	2,289	$	1,848	$	441
Technology and other	436		363		73		407		357		50
Tradenames	14		14		—		14		13		1
Total	$	2,657	$	2,210	$	447	$	2,710	$	2,218	$	492

Amortization expense and impairment charges from finite lived intangible assets were $113 million, $147 million, and $246 million for the years ended December 31, 2022, 2021, and 2020, respectively.

The estimated future amortization for finite-lived intangible assets as of December 31, 2022 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2023	$	99
2024	82
2025	68
2026	47
2027	34
Thereafter	117
Total	$	447

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7.    Debt

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

As of December 31	2022		2021
Commercial paper	$	592	$	665
2.20% Senior Notes due November 2022 (1)	—		499
4.00% Senior Notes due November 2023 (2)	350		349
3.50% Senior Notes due June 2024	599		598
3.875% Senior Notes due December 2025	748		748
2.875% Senior Notes due May 2026 (EUR 500M)	530		563
8.205% Junior Subordinated Notes due January 2027	521		521
2.85% Senior Notes due May 2027	596		—
4.50% Senior Notes due December 2028	348		347
3.75% Senior Notes due May 2029	746		745
2.80% Senior Notes due May 2030	994		993
2.05% Senior Notes due August 2031	396		396
2.60% Senior Notes due December 2031	496		496
5.00% Senior Notes due September 2032	495		—
6.25% Senior Notes due September 2040	297		296
4.25% Senior Notes due December 2042	203		201
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	545		544
4.75% Senior Notes due May 2045	594		593
2.90% Senior Notes due August 2051	591		591
3.90% Senior Notes due February 2052	877		—
Other	5		—
Total debt	10,770		9,392
Less: Short-term debt and current portion of long-term debt	945		1,164
Total long-term debt	$	9,825	$	8,228

(1)The 2.20% Senior Notes due November 2022 were repaid in full on November 1, 2022.

(2)The 4.00% Senior Notes due November 2023 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2022.

Notes

In November 2022, Aon Global Limited’s $350 million 4.00% Senior Notes due November 2023 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2022.

In November 2022, Aon Corporation’s $500 million 2.20% Senior Notes matured and were repaid in full. 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 Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2021.

On September 12, 2022, 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 $500 million of 5.00% Senior Notes due September 2032. The Company intends to use the net proceeds from the offering for general corporate purposes.

On February 28, 2022, Aon Corporation and Aon Global Holdings plc co-issued $600 million of 2.85% Senior Notes due May 2027 and $900 million of 3.90% Senior Notes due February 2052. The Company intends to use the net proceeds from the offering for general corporate purposes.

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On December 2, 2021, Aon Corporation and Aon Global Holdings plc 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 and Aon Global Holdings plc 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 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. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

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. Each of the notes co-issued by Aon Corporation and Aon Global Holdings plc is fully and unconditionally guaranteed by Aon plc and Aon Global Limited. 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, 2022.

Repayments of total debt as of December 31, 2022 are as follows (in millions):

2023	$	946
2024	604
2025	750
2026	532
2027	1,121
Thereafter	6,956
Total Repayments	10,909
Unamortized discounts, premiums, and debt issuance costs	(139)
Total Debt	$	10,770

Revolving Credit Facilities

As of December 31, 2022, 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 2024. In aggregate, these two facilities provide approximately $1.8 billion in available credit.

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, 2022, 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, 2022.

Commercial Paper

Commercial paper may be issued in aggregate principal amounts of up to $1 billion under the U.S. Program and €625 million ($665 million at December 31, 2022 exchange rates) under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was approximately $1.8 billion at December 31, 2022. 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.

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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	2022		2021
Commercial paper outstanding	$	592	$	665

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

	Years Ended December 31
	2022			2021
Weighted average commercial paper outstanding	$	499		$	273
Weighted average interest rate of commercial paper outstanding	1.42		%	0.01		%

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		2022		2021
Assets
Operating lease assets	Operating lease right-of-use assets	$	699	$	786
Finance lease assets	Other non-current assets	43		63
Total lease assets		$	742	$	849
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	163	$	194
Finance	Other current liabilities	23		19
Non-current lease liabilities
Operating	Non-current operating lease liabilities	693		772
Finance	Other non-current liabilities	28		46
Total lease liabilities		$	907	$	1,031

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

	Years Ended December 31
	2022		2021
Operating lease cost	$	204	$	217
Finance lease costs
Amortization of leased assets	28		26
Interest on lease liabilities	1		1
Variable lease cost	38		49
Short-term lease cost (1)	11		11
Sublease income	(29)		(31)
Net lease cost	$	253	$	273

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

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

As of December 31	2022		2021
Weighted average remaining lease term (years)
Operating leases	6.7		6.9
Finance leases	2.5		3.6
Weighted average discount rate
Operating leases	3.1	%	2.8	%
Finance leases	1.0	%	1.0	%

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

	Years Ended December 31
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	231	$	244
Financing cash flows for finance leases	$	14	$	23
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	110	$	44
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	—
Operating lease ROU asset expense (1)	$	162	$	142
Changes in Non-current operating lease liabilities (1)	$	(79)	$	(125)

(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, 2022 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2023	$	175	$	23	$	198
2024	164		18		182
2025	135		10		145
2026	123		—		123
2027	108		—		108
Thereafter	235		—		235
Total undiscounted future minimum lease payments	940		51		991
Less: Imputed interest	(84)		—		(84)
Present value of lease liabilities	$	856	$	51	$	907

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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
	2022		2021		2020
Income (loss) before income taxes:
Ireland	$	85	$	15	$	(86)
U.K.	502		549		634
U.S.	161		(818)		(28)
Other	2,408		2,185		1,946
Total	$	3,156	$	1,931	$	2,466
Income tax expense:
Current:
Ireland	$	2	$	2	$	2
U.K.	206		50		30
U.S. federal	195		197		126
U.S. state and local	43		72		22
Other	316		291		259
Total current tax expense	$	762	$	612	$	439
Deferred tax expense (benefit):
Ireland	$	—	$	(1)	$	(1)
U.K.	(152)		131		39
U.S. federal	(69)		(83)		(72)
U.S. state and local	(21)		(30)		(4)
Other	(10)		(6)		47
Total deferred tax expense (benefit)	$	(252)	$	11	$	9
Total income tax expense	$	510	$	623	$	448

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. The reconciliation of the income tax provisions based on the Irish statutory corporate tax rate of 25% to the provisions reflected in the Consolidated Financial Statements is as follows:

	Years Ended December 31
	2022	2021	2020
Statutory tax rate	25.0%	25.0%	25.0%
U.S. state income taxes, net of U.S. federal benefit	0.4	1.5	1.0
Taxes on international operations (1) (2)	(11.6)	(15.4)	(9.8)
Nondeductible expenses	2.4	3.3	2.1
Adjustments to prior year tax requirements	(7.0)	(0.2)	—
Deferred tax adjustments, including statutory rate changes	(0.5)	3.2	0.7
Deferred tax adjustments, international earnings	0.2	1.8	0.7
Adjustments to valuation allowances	1.9	(0.2)	—
Change in uncertain tax positions	8.6	2.1	1.5
Excess tax benefits related to shared based compensation (3)	(1.5)	(2.4)	(2.2)
Capital and other losses	(1.4)	—	(1.8)
Non-deductible transaction costs	—	1.1	1.3
Non-deductible termination fee	—	12.9	—
Other — net	(0.3)	(0.4)	(0.3)
Effective tax rate	16.2%	32.3%	18.2%

(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 25.0% at December 31, 2022, 2021, and 2020, 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)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 2022 and therefore recorded the impact of making the election.

(3)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.

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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	2022		2021
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	952	$	581
Lease liabilities	178		207
Employee benefit plans	297		160
Other accrued expenses	100		132
Accrued interest	—		97
Federal and state benefit of interest from uncertain tax positions	57		45
Deferred revenue	26		36
Investment basis differences	30		25
Lease and service guarantees	1		1
Other	38		25
Total	1,679		1,309
Valuation allowance on deferred tax assets	(275)		(230)
Total	$	1,404	$	1,079
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(258)	$	(243)
Lease right-of-use asset	(151)		(173)
Deferred costs	(147)		(159)
Unremitted earnings	(38)		(58)
Other accrued expenses	(20)		(27)
Unrealized foreign exchange gains	(23)		(22)
Other	(42)		(32)
Total	$	(679)	$	(714)
Net deferred tax asset	$	725	$	365

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	2022		2021
Deferred tax assets — non-current	$	824	$	766
Deferred tax liabilities — non-current	(99)		(401)
Net deferred tax asset	$	725	$	365

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 tax credits and net operating losses, capital losses, and interest carryforwards. Valuation allowances increased by $45 million as of December 31, 2022, when compared to December 31, 2021. The change is primarily attributable to an increase in valuation allowances related to net operating losses and foreign tax credits.

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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, 2022, the Company has accrued $38 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	2022		2021
U.K.
Operating loss carryforwards	$	608	$	41
Capital loss carryforwards	$	533	$	573
U.S.
Federal operating loss carryforwards	$	1	$	25
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	2,269	$	1,140
Federal foreign tax credit carryforwards	$	20	$	18
State operating loss carryforwards	$	473	$	398
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	1,187	$	551
Other Non-U.S.
Operating loss carryforwards	$	490	$	301
Capital loss carryforwards	$	8	$	35
Interest carryforwards	$	26	$	26
Other carryforwards	$	5	$	5

The U.K. operating losses and capital losses 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, 2022 have various carryforward periods and will begin to expire in 2023. Federal and state capital losses can be carried forward until 2023. Federal and state interest carryforwards have indefinite carryforward periods. Foreign tax credits can be carried forward for ten years and will begin to expire in 2028. Operating, capital losses, and other carryforwards in other non-U.S. jurisdictions have various carryforward periods and will begin to expire in 2023. 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. The Company has been granted a new incentive for the period October 1, 2022 to September 30, 2032. The new incentive provides for a reduced withholding tax rate and a reduced tax rate on certain income derived from services in Singapore, as long as certain conditions are met.

The benefit realized was approximately $115 million, $104 million, and $97 million during the years ended December 31, 2022, 2021, and 2020, respectively. The impact of this tax holiday on diluted earnings per share was $0.54, $0.46, and $0.42 during the years ended December 31, 2022, 2021, and 2020, 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):

	2022		2021
Balance at January 1	$	347	$	321
Additions based on tax positions related to the current year	35		33
Additions for tax positions of prior years	226		7
Reductions for tax positions of prior years	(1)		(4)
Settlements	(1)		—
Business combinations	—		—
Lapse of statute of limitations	(5)		(10)
Foreign currency translation	—		—
Balance at December 31	$	601	$	347

The Company’s liability for uncertain tax positions as of December 31, 2022, 2021, and 2020, includes $535 million, $295 million, and $270 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 $40 million, $22 million, and $21 million in 2022, 2021, and 2020, respectively. The Company recorded a liability for interest and penalties of $181 million, $142 million, and $120 million as of December 31, 2022, 2021, and 2020, 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 2014. The Company has concluded income tax examinations in its primary non-U.S. jurisdictions through 2008.

10.    Shareholders’ Equity (Deficit)

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., accumulated deficit). As of December 31, 2022 and 2021, the Company had distributable profits in excess of $29.0 billion and $32.7 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 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.

78

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

	Years Ended December 31
	2022		2021
Shares repurchased	11.1		12.4
Average price per share	$	289.76	$	286.82
Repurchase costs recorded to accumulated deficit	$	3,203	$	3,543

At December 31, 2022, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $6.0 billion. Under the Repurchase Program, the Company has repurchased a total of 160.7 million shares for an aggregate cost of approximately $21.5 billion.

Weighted Average Ordinary Shares

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

	Years Ended December 31
	2022	2021	2020
Basic weighted average ordinary shares outstanding	211.7	224.7	231.9
Dilutive effect of potentially issuable shares	1.5	1.4	1.2
Diluted weighted average ordinary shares outstanding	213.2	226.1	233.1

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 0.8 million and 0.3 million shares excluded from the calculation in 2022 and 2021, respectively, and no shares excluded from the calculation in 2020.

79

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, 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	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	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)
Other comprehensive income (loss) before reclassifications:
Other comprehensive loss before reclassifications	(15)		(528)		(569)		(1,112)
Tax benefit (expense)	4		—		149		153
Other comprehensive loss before reclassifications, net	(11)		(528)		(420)		(959)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income (loss)	(2)		—		282		280
Tax expense	—		—		(73)		(73)
Amounts reclassified from accumulated other comprehensive income (loss), net	(2)		—		209		207
Net current period other comprehensive loss	(13)		(528)		(211)		(752)
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)

(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.

80

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
	2022		2021		2020
U.S.	$	108	$	103	$	87
U.K.	47		46		42
Netherlands and Canada	33		35		26
Total	$	188	$	184	$	155

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.

81

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, 2022 and 2021, and a statement of the funded status as of December 31, 2022 and 2021, 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 88% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2022		2021		2022		2021		2022		2021
Change in projected benefit obligation
At January 1	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Service cost	1		1		—		—		—		—
Interest cost	83		65		73		57		19		12
Settlements	—		(14)		(283)		—		—		—
Actuarial (gain) loss	(1,418)		(292)		(607)		(103)		(322)		24
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(444)		(58)		—		—		(89)		(83)
As of December 31	$	2,946	$	4,919	$	2,180	$	3,164	$	1,094	$	1,531
Accumulated benefit obligation at end of year	$	2,946	$	4,919	$	2,180	$	3,164	$	1,079	$	1,504
Change in fair value of plan assets
At January 1	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Actual return on plan assets	(1,961)		(136)		(484)		211		(284)		46
Employer contributions	7		9		37		61		15		17
Settlements	—		(14)		(283)		—		—		—
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(559)		(76)		—		—		(83)		(83)
As of December 31	$	3,537	$	6,246	$	1,481	$	2,378	$	1,032	$	1,430
Market related value at end of year	$	3,537	$	6,246	$	1,794	$	2,174	$	1,032	$	1,430
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	591	$	1,327	$	(699)	$	(786)	$	(62)	$	(101)
Unrecognized prior-service cost	35		40		—		—		(6)		(6)
Unrecognized loss	1,726		1,215		1,305		1,551		443		489
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

The benefit obligation decreased primarily as a result of increases in the discount rates in 2022 as compared to 2021. The value of plan assets decreased as a result of negative asset returns, predominately in the U.K, and overall weaker exchange rates versus the U.S. Dollar. The U.K. pension assets are concentrated in fixed income and annuities which were disproportionately negatively impacted by the rising interest rate environment. The U.K. hedging strategy continues to perform as expected and the related pension plans remain over-funded. Net actuarial gains decreased the benefit obligation in 2021 primarily due to the increase in the discount rates.

In November 2022, to further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. The transaction settled $280 million of benefit obligations using $280 million of assets.

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.

82

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

	U.K.				U.S.				Other
	2022		2021		2022		2021		2022		2021
Prepaid benefit cost (1)	$	612	$	1,344	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(42)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(20)		(16)		(657)		(734)		(57)		(96)
Accumulated other comprehensive loss	1,761		1,255		1,305		1,551		437		483
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

(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, 2022 and 2021 consist of (in millions):

	U.K.				U.S.				Other
	2022		2021		2022		2021		2022		2021
Net loss	$	1,726	$	1,215	$	1,305	$	1,551	$	443	$	489
Prior service cost (income)	35		40		—		—		(6)		(6)
Total	$	1,761	$	1,255	$	1,305	$	1,551	$	437	$	483

In 2022, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $2.2 billion, an ABO of $2.2 billion, and plan assets with a fair value of $1.5 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $114 million, an ABO of $114 million and, plan assets with a fair value of $93 million. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.1 billion and plan assets with a fair value of $1.0 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $220 million and plan assets with a fair value of $166 million.

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.

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
	2022		2021		2020		2022		2021		2020		2022		2021		2020
Service cost	$	1	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	83		65		88		73		57		85		19		12		19
Expected return on plan assets, net of administration expenses	(134)		(137)		(159)		(108)		(130)		(134)		(33)		(32)		(34)
Amortization of prior-service cost	2		2		2		—		—		1		—		—		—
Amortization of net actuarial loss	29		32		30		61		78		68		13		15		12
Net periodic benefit (income) cost	(19)		(37)		(39)		26		5		20		(1)		(5)		(3)
Settlement expense	—		5		2		170		—		—		—		—		—
Total net periodic benefit cost (income)	$	(19)	$	(32)	$	(37)	$	196	$	5	$	20	$	(1)	$	(5)	$	(3)

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.

83

In November 2022, to further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. 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 of approximately $170 million in 2022.

Transfer payments from certain U.K. pension plans exceeded the plan’s service and interest cost in 2021 and 2020. 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), and approximately £2 million in 2020 ($2 million using December 31, 2020 exchange rates).

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

	U.K.		U.S. (1)		Other
	2022	2021	2022	2021	2022	2021
Discount rate	4.89%	1.96%	4.82 - 5.03%	2.23 - 2.8%	3.23 - 5.19%	1.00 - 2.97%
Rate of compensation increase	3.59 - 4.09%	3.62 - 4.12%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.44%	2.52%	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
	2022	2021	2020	2022	2021	2020	2022	2021	2020
Discount rate	1.85%	1.20%	1.89%	1.67 - 2.25%	1.12 - 1.79%	2.36 - 2.76%	0.84 - 2.58%	0.28 - 2.00%	0.74 - 2.90%
Expected return on plan assets, net of administration expenses	2.34%	2.04%	2.74%	2.03 - 5.28%	2.65- 6.56%	3.30%-7.04%	1.80 - 3.15%	1.70 - 2.65%	2.10 - 3.10%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	3.24 - 3.74%	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 5.28% 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 2023.

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.

84

The fair values of the Company’s U.S. pension plan assets at December 31, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2022		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)	$	42	$	42	$	—	$	—
Equity investments:
Equity securities	64		64		—		—
Equity derivatives	(6)		—		(6)		—
Pooled funds (2)	293		—		—		—
Fixed income investments:
Corporate bonds	192		—		192		—
Government and agency bonds	149		124		25		—
Pooled funds (2)	507		—		—		—
Other investments:
Real estate (2) (3)	113		—		—		—
Alternative investments (2) (4)	127		—		—		—
Total	$	1,481	$	230	$	211	$	—

			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	$	—

(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.

85

The fair values of the Company’s major U.K. pension plan assets at December 31, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	336	$	336	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(548)		—		(548)		—
Government and agency bonds	1,593		1,593		—		—
Annuities	1,403		—		—		1,403
Pooled funds (2)	139		—		—		—
Other investments:
Real estate (2) (4)	97		—		—		—
Pooled funds (2) (5)	517		—		—		—
Total	$	3,537	$	1,929	$	(548)	$	1,403

			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

(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.

86

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, 2022 and December 31, 2021 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2021	$	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchase, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	2,305
Actual return on plan assets:
Relating to assets still held at December 31, 2022	(674)
Purchases, sales and settlements-net	—
Foreign exchange	(228)
Balance at December 31, 2022	$	1,403

The fair values of the Company’s other major pension plan assets at December 31, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	30	$	30	$	—	$	—
Equity investments:
Equity securities	53		53		—		—
Pooled funds (2)	211		—		—		—
Fixed income investments:
Government and agency bonds	225		225		—		—
Derivatives	(3)		—		(3)		—
Pooled funds (2)	462		—		—		—
Other investments:
Alternative investments (2) (3)	42		—		—		—
Real estate (2) (4)	12		—		—		—
Total	$	1,032	$	308	$	(3)	$	—

87

			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	$	—	$	—

(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, 2022, the weighted average targeted allocation for the U.S. plans was 30% for equity investments, 54% for fixed income investments, and 16% 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, 2022, the weighted average targeted allocation for the U.K. and non-U.S. plans was 6% for equity investments, 86% for fixed income investments, and 8% for other investments.

Cash Flows

Contributions

Based on current assumptions, in 2023, the Company expects to contribute approximately $4 million, $43 million, and $14 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, 2022 (in millions):

	U.K.		U.S.		Other
2023	$	153	$	157	$	46
2024	$	157	$	158	$	47
2025	$	161	$	158	$	49
2026	$	166	$	162	$	50
2027	$	170	$	155	$	51
2028 - 2032	$	905	$	754	$	274

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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, 2022 and 2021 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2022		2021
Accumulated projected benefit obligation	$	83	$	109
Fair value of plan assets	14		17
Funded status	(69)		(92)
Unrecognized prior-service credit	(1)		(1)
Unrecognized (gain) loss	(19)		2
Net amount recognized	$	(89)	$	(91)

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

	2022	2021	2020
Net periodic benefit cost recognized (millions)	$3	$5	$4
Weighted-average discount rate used to determine future benefit obligations	4.94 - 5.19%	2.52 - 3.06%	2.10 - 2.58%
Weighted-average discount rate used to determine net periodic benefit costs	1.97 - 2.69%	1.45 - 2.68%	2.93 - 3.25%

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 2023 is $0.8 million net gain and $0.2 million of prior-service credit.

•To contribute $5 million to fund significant other postretirement benefit plans during 2023.

•Estimated future benefit payments will be approximately $5 million each year for 2023 through 2027, and $27 million in aggregate for 2028-2032.

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
	2022		2021		2020
Restricted share units	$	251	$	204	$	186
Performance share awards	134		189		116
Employee share purchase plans and other (1)	12		56		10
Total share-based compensation expense	397		449		312
Tax benefit	83		87		61
Share-based compensation expense, net of tax	$	314	$	362	$	251

(1) 2021 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):

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	3,075	$	203
Granted	1,117	$	279
Vested	(1,154)	$	187
Forfeited	(175)	$	219
Non-vested balance at December 31, 2022	2,863	$	238

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

The weighted-average grant date fair value of the Company's RSU awards granted during the years ended December 31, 2022, December 31, 2021, and December 31, 2020 was $279, $253, and $185, respectively. The fair value of RSUs that vested during 2022, 2021, and 2020 was $216 million, $189 million, and $190 million, respectively.

Unamortized deferred compensation expense amounted to $466 million as of December 31, 2022, with a remaining weighted average amortization period of approximately 2.0 years.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of adjusted diluted 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, reduced by the present value of estimated dividends foregone during the vesting period. 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 status of the Company's PSAs at 100% of the targeted amount (shares in thousands, except fair value):

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	1,298	$	181
Granted	300	$	311
Vested	(444)	$	163
Forfeited	(18)	$	217
Non-vested balance at December 31, 2022	1,136	$	222

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

The per share weighted-average grant date fair value of the Company's PSA awards granted during the years ended December 31, 2022, December 31, 2021, and December 31, 2020 was $311, $225, and $163, respectively. The payout of shares in 2022 with respect to the PSA awards granted in 2019 based on performance for the three-year performance period ended 2021 was, in aggregate, 888 thousand shares. The fair value of PSAs that vested during 2022, 2021, and 2020 was $145 million, $112 million, and $121 million, respectively.

Unamortized compensation expense, based on current performance levels, amounted to $126 million as of December 31, 2022, with a remaining weighted average amortization period of approximately 1.3 years.

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.

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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 (expense) 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
As of December 31	2022		2021		2022		2021		2022		2021
Foreign exchange contracts
Accounted for as hedges	$	618	$	629	$	12	$	27	$	2	$	—
Not accounted for as hedges (3)	312		412		—		2		1		—
Total	$	930	$	1,041	$	12	$	29	$	3	$	—

(1)Included within Other current assets ($3 million in 2022 and $21 million in 2021) or Other non-current assets ($9 million in 2022 and $8 million in 2021).

(2)Included within Other current liabilities ($2 million in 2022) or Other non-current liabilities ($1 million in 2022).

(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):

	2022		2021		2020
(Loss) gain recognized in Accumulated other comprehensive loss	$	(15)	$	—	$	1

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
	2022		2021		2020
Total revenue	$	2	$	(3)	$	(14)
Compensation and benefits	—		1		—
Interest expense	—		—		(1)
Total	$	2	$	(2)	$	(15)

The Company estimates that approximately $10 million of pretax loss currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

The Company recorded a gain of $11 million in 2022, a loss of $24 million in 2021, and a gain of $1 million in 2020 in Other income (expense) for foreign exchange derivatives not designated or qualifying as hedges.

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

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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, 2022 and December 31, 2021 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	3,323	$	3,323	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	19	$	—	$	19	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	9	$	—	$	9	$	—

			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	$	—

(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 2022 or 2021. 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 2022, 2021, or 2020.

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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):

	2022				2021
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	350	$	347	$	499	$	507
Long-term debt	$	9,825	$	8,745	$	8,228	$	9,204

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 is not subject to current matters in connection with which the Company believes (1) material loss (including interest and costs) is probable, (2) material loss (including interest and costs) is reasonably possible (that is, more than remote but not probable), or (3) there exists the reasonable possibility of material loss (including interest and costs) greater than the accrued amount. The Company includes in the current matters described below certain matters in which it believes a material loss is remote but in which the claimed amounts are significant. Although management at present believes that the ultimate outcome of such matters, 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

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 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 ERISA. 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, and oral argument took place on December 7, 2022. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims and appeal.

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 cooperated with that inquiry. In August 2020, 43 individuals (surviving passengers and estates of the deceased) filed a motion in the Circuit Court of

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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 ($35 million at December 31, 2022 exchange rates). In December 2022, the High Court in England granted an anti-suit injunction, restricting the 43 individuals who previously filed a motion in the Circuit Court of the 11th Judicial Circuit in and for Miami-Dade County, Florida, from continuing litigation in the Circuit Court of the 11th Judicial Circuit against Aon. Aon believes that it has meritorious defenses and intends to vigorously defend itself against the remaining claims.

Settled/Closed 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 claimed damages of approximately NZD 320 million ($202 million at December 31, 2022 exchange rates) plus interest and costs. In December 2022, the case was settled with no admission of liability on the part of Aon.

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 Ireland Reorganization, on April 1, 2020, Aon plc and Aon Global Holdings plc 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).

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 $74 million at December 31, 2022, and $75 million at December 31, 2021. 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.

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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 $173 million at December 31, 2022 compared to $153 million at December 31, 2021.

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, 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
2022	$	1,300	$	519	$	120	$	155	$	9	$	279	$	218
2021	$	1,378	$	563	$	121	$	180	$	7	$	293	$	214

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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, 2022. Based on this evaluation, our chief executive officer and chief financial officer concluded as of December 31, 2022 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, 2022. 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, 2022.

The effectiveness of our internal control over financial reporting as of December 31, 2022 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 2022 that have materially affected, or that are reasonably likely to materially affect, Aon’s internal control over financial reporting.

97

Report of Independent Registered Public Accounting Firm

To the Shareholders and the Board of Directors 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, 2022, 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, 2022, 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, 2022 and 2021, the related consolidated statements of income, comprehensive income, shareholders' equity (deficit) and cash flows for each of the three years in the period ended December 31, 2022, and the related notes and our report dated February 17, 2023 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 17, 2023

98

Item 9B.    Other Information

Not applicable.

Item 9C.    Disclosure Regarding Foreign Jurisdictions that Prevents Inspections

Not applicable.

99

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 2023 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 “Director Nominee Bios” and “Corporate Governance” 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 “Other Information - 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.

100

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, 2022 and 2021
	Consolidated Statements of Income — Years Ended December 31, 2022, 2021, and 2020
	Consolidated Statements of Comprehensive Income — Years Ended December 31, 2022, 2021 and 2020
	Consolidated Statements of Shareholders’ Equity — Years Ended December 31, 2022, 2021 and 2020
	Consolidated Statements of Cash Flows — Years Ended December 31, 2022, 2021 and 2020
	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)
	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.
		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.

101

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.
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.
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.

102

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.
4.31*	Third Indenture Supplement, dated February 28, 2022, 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’ Current Report on Form 8-K filed February 28, 2022.
4.32*	Form of 2.850% Senior Note due 2027 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed February 28, 2022.
4.33*	Form of 3.900% Senior Note due 2052 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed February 28, 2022.
4.34*	Fourth Indenture Supplement, dated September 12, 2022, 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’ Current Report on Form 8-K filed September 12, 2022.
4.35*	Form of 5.000% Senior Note due 2032 – incorporated by reference to Exhibit 4.2 to Aon’s Current Report on Form 8-K filed September 12, 2022.

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*	Amendment No. 3 to the 2017 Credit Agreement, dated October 19, 2022, 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 10.1 to Aon’s Current Report on Form 8-K filed on October 21, 2022.
	10.8*	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.
	10.9*	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.

103

10.10*#	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.
10.11*#	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.
10.12*#	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.
10.13*#	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.
10.14*#	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.
10.15*#	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.
10.16*#	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.
10.17*#	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.
10.18*#	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.
10.19*#	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.
10.20*#	Aon plc Leadership Performance Program (as amended and restated, effective January 1, 2021) - incorporated by reference to Exhibit 10.20 to Aon’s Annual Report on Form 10-K for the year ended December 31, 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.

104

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.
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*#	Amendment to International Assignment Letter, dated June 21, 2022, between Aon Corporation and Gregory C. Case – incorporated by reference to exhibit 10.2 to Aon’s Current Report on Form 8-K filed June 23, 2022.
10.41*#	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.
10.42*#	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.
10.43*#	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.
10.44*#	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.
10.45*#	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.
10.46*#	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
10.47*#	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.
10.48*#	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.
10.49*#	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.

105

10.50*#	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.
10.51*#	Amendment to International Assignment Letter, dated June 21, 2022, between Aon Corporation and Christa Davies – incorporated by reference to Exhibit 10.1 to Aon’s Current Report on Form 8-K filed June 23, 2022.
10.52*#	Letter Agreement, dated July 16, 2019, between Aon Corporation and Darren Zeidel - incorporated by reference to Exhibit 10.50 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2021
10.53*#	Letter Agreement, dated October 22, 2019, between Aon Corporation and Lisa Stevens - incorporated by reference to Exhibit 10.51 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2021.
10.54*#	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.
10.55*#	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.
10.56*#	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.
10.57*#	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.
10.58*#	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.
10.59*#	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.
10.60*#	Fifth Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective October 1, 2021 - incorporated by reference to Exhibit 10.64 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2021.
10.61#	Sixth Amendment to the Amended and Restated Aon Deferred Compensation Plan, effective June 30, 2022.
10.62*#	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.
10.63*#	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.
10.64*#	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.
10.65*#	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.
10.66*#	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.
10.67*#	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.
10.68*#	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.
10.69*#	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.
10.70*#	Sixth Amendment to the Aon Supplemental Savings Plan, effective October 1, 2021 - incorporated by reference to Exhibit 10.74 to Aon’s Annual Report on Form 10-K for the year ended December 31, 2021.
10.71#	Seventh Amendment to the Aon Supplemental Savings Plan, effective June 30, 2022.

106

	10.72*#	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.
	10.73*#	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.
	10.74*#	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.
	10.75*	Form of Irrevocable Director Undertaking - incorporated by reference to Exhibit 10.1 to Aon’s Form 8-K filed March 10, 2020.
	10.76*#	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.
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.

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.

107

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.

108

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 17, 2023

    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 17, 2023
Gregory C. Case
/s/ LESTER B. KNIGHT	Non-Executive Chairman and Director	February 17, 2023
Lester B. Knight
/s/ JIN-YONG CAI	Director	February 17, 2023
Jin-Yong Cai
/s/ JEFFREY C. CAMPBELL	Director	February 17, 2023
Jeffrey C. Campbell
/s/ FULVIO CONTI	Director	February 17, 2023
Fulvio Conti
/s/ CHERYL A. FRANCIS	Director	February 17, 2023
Cheryl A. Francis
/s/ ADRIANA KARABOUTIS	Director	February 17, 2023
Adriana Karaboutis
/s/ J. MICHAEL LOSH	Director	February 17, 2023
J. Michael Losh
/s/ RICHARD C. NOTEBAERT	Director	February 17, 2023
Richard C. Notebaert
/s/ GLORIA SANTONA	Director	February 17, 2023
Gloria Santona
/s/ BYRON SPRUELL	Director	February 17, 2023
Byron Spruell
/s/ CAROLYN Y. WOO	Director	February 17, 2023
Carolyn Y. Woo
/s/ CHRISTA DAVIES	Chief Financial Officer (Principal Financial Officer)	February 17, 2023
Christa Davies
/s/ MICHAEL NELLER	Global Controller (Principal Accounting Officer)	February 17, 2023
Michael Neller

109

EX-4.25

Exhibit 4.25

Description of the Share Capital of Aon Ireland

Set forth below is a summary of the material terms of the share capital of Aon plc, an Irish public limited company ("Aon Ireland"). The summary is subject to the Companies Act 2014 of Ireland, as amended (the "Irish Companies Act"), and is qualified in its entirety by reference to the Aon Ireland Constitution, which is filed as Exhibit 3.1 to Aon Ireland's Current Report on Form 8-K filed on June 4, 2021 and incorporated by reference herein.

Capital Structure

Authorized Share Capital

Aon Ireland's authorized share capital is $5,500,000 and €25,000, divided into 500,000,000 Class A ordinary shares of $0.01 each, 50,000,000 preference shares of $0.01 each and 25,000 ordinary shares of €1 each. Aon Ireland's authorized share capital includes €25,000 divided into 25,000 ordinary shares of €1 each ("Euro Ordinary Shares") in order to satisfy minimum statutory capital requirements for all Irish public limited companies. Any holder of the Euro Ordinary Shares is not entitled to receive any dividend or other distribution, or to attend, speak or vote at any general meeting, and has no effective rights to participate in Aon Ireland's assets.

Aon Ireland may allot and issue shares subject to the maximum authorized share capital contained in the Aon Ireland Constitution. The maximum authorized share capital may be increased or reduced by a simple majority of votes cast, in person or by proxy, at a general meeting of Aon Ireland's shareholders at which a quorum is present (referred to under Irish law as an "ordinary resolution").

Under Irish law, the board of directors of a company may issue shares having the rights provided for in its constitution without shareholder approval once authorized to do so by its constitution or by an ordinary resolution adopted by its shareholders at a general meeting, subject at all times to the maximum authorized share capital. The authorization may be granted for a period of up to five years, at which point it must be renewed by such company's shareholders by an ordinary resolution. The Aon Ireland Constitution authorize Aon Ireland's board of directors to issue shares in the capital of Aon Ireland having the rights provided for in the Aon Ireland Constitution without approval of Aon Ireland's shareholders for a period of five years from the date of adoption of the Aon Ireland Constitution (which occurred on March 31, 2020) up to the maximum authorized, but unissued, share capital. The rights and restrictions of Aon Ireland's share capital are set forth in the Aon Ireland Constitution.

Irish law does not recognize fractional shares held of record. Accordingly, the Aon Ireland Constitution does not provide for the issuance of fractional shares, and Aon Ireland's register of members (i.e., share register) will not reflect any fractional shares.

Whenever an alteration or reorganization of Aon Ireland's share capital would result in any of Aon Ireland's shareholders becoming entitled to fractions of a share, Aon Ireland's board of directors is entitled, on behalf of those shareholders that would become entitled to fractions of a share, to arrange for the sale of the shares representing fractions and to distribute the net proceeds of such sale in due proportion among those shareholders who would have been entitled to the fractions. For this purpose, Aon Ireland's board of directors is entitled to authorize any person to execute any instruments or other documents required to transfer the shares representing fractions to the transferee thereof. The transferee shall not be bound to see to the application of the purchase money, nor shall his or her title to the shares be affected by any irregularity in, or invalidity of, the proceedings relating to the sale.

Issued Share Capital

In connection with the Reorganization, Aon Ireland issued approximately 232 million Aon Ireland Shares to the former shareholders of Aon Global Limited (f/k/a Aon plc), a company incorporated under the laws of England and Wales ("Aon UK"). All Aon Ireland Shares issued in connection with the Reorganization were duly and validly issued and credited as fully paid-up.

Under the Aon Ireland Constitution, subject to the Irish Companies Act, Aon Ireland's board of directors (or an authorized committee thereof) is authorized to approve the reclassification, allotment, issuance, grant and disposal of, or otherwise deal with, shares, options, equity awards, rights over shares, warrants, other securities and derivatives in, or of, Aon Ireland to such persons, at such times and on such terms and conditions as it deems advisable (including specifying the conditions of allotment of shares for the purposes of the Irish Companies Act).

Preemption Rights, Share Warrants and Options

Under Irish law, certain statutory preemption rights apply automatically in favor of shareholders where shares are to be issued for cash. These statutory preemption rights may be disapplied in a company's constitution or by a special resolution adopted by its shareholders at a general meeting. A "special resolution" requires the approval of at least 75% of the votes cast, in person or by proxy, at a general meeting of shareholders at which a quorum is present. The statutory preemption rights may be disapplied for a period of up to five years, at which point the disapplication must be renewed by the shareholders by a special resolution. The Aon Ireland Constitution disapplies the statutory preemption rights for a period of five years from the date of its adoption (which occurred on March 31, 2020) in respect of the issue of up to the maximum authorized, but unissued, share capital. The disapplication of statutory preemption rights will need to be renewed by special resolution upon the expiration of this five-year period and at periodic intervals thereafter. If the disapplication is not renewed, any further shares proposed to be issued for cash will require to be first offered to Aon Ireland's shareholders at the relevant time on a pro rata basis to their then existing shareholding before the shares may be issued to proposed new shareholders. Statutory preemption rights do not apply:

•    where shares are issued for non-cash consideration (such as in a share-for-share acquisition);

•    to the issue of non-equity shares (i.e., shares that have the right to participate only up to a specified amount in any income or capital distribution); or

•    where shares are issued pursuant to employee share plans.

The Aon Ireland Constitution provides that, subject to any shareholder approval requirement under any laws, regulations or the rules of any stock exchange to which Aon Ireland is subject, Aon Ireland's board of directors is authorized, from time to time, to grant such persons, for such periods and upon such terms and conditions as it deems advisable, options to purchase or to subscribe for such number of shares of any class or classes or of any series of any class, and to cause warrants or other appropriate instruments evidencing such options to be issued. Aon Ireland is subject to the rules of the NYSE and U.S. federal tax laws that require shareholder approval of certain equity plans and share issuances.

Dividends

Under Irish law, dividends and distributions may only be made from distributable profits. Distributable profits mean a company's accumulated realized profits, so far as not previously utilized by distribution or capitalization, less its accumulated realized losses, so far as not previously written off in a reduction or reorganization of capital, duly made, and include reserves created by way of a court approved share capital reduction. In addition to the requirement to have distributable profits, no distribution or dividend may be made by Aon Ireland unless, at the relevant time, its net assets are not less than the aggregate of its called-up share capital and its undistributable reserves and the distribution or dividend does not reduce its net assets below such aggregate.

Undistributable reserves include: (i) a company's undenominated capital; (ii) the amount by which a company's accumulated unrealized profits, so far as not previously utilized by any capitalization, exceed its accumulated unrealized losses, so far as not previously written off in a reduction or reorganization of capital; and (iii) any other reserve a company is prohibited, at law, from distributing.

The determination as to whether or not Aon Ireland has sufficient distributable profits to fund a dividend must be made by reference to Aon Ireland's "relevant entity financial statements." The "relevant entity financial statements" will be either the last set of unconsolidated annual audited financial statements or "initial" or "interim" financial statements properly prepared in accordance with the Irish Companies Act and applicable accounting standards. The relevant entity financial statements are required to be filed in the Companies Registration Office (the official public registry for companies in Ireland).

The Aon Ireland Constitution authorizes Aon Ireland's board of directors to declare dividends without approval of Aon Ireland's shareholders if Aon Ireland's board of directors considers the financial position of Aon Ireland to justify such payment. Aon Ireland's board of directors may also recommend a dividend to be approved and declared by Aon Ireland's shareholders at an annual general meeting of shareholders. No dividend may exceed the amount recommended by Aon Ireland's board of directors. Dividends may be declared and paid in the form of cash, property, paid-up shares or debentures of another company.

Aon Ireland's board of directors may deduct from any dividend payable to any shareholder of Aon Ireland any amounts payable by such shareholder to Aon Ireland in relation to the shares of Aon Ireland held by such shareholder.

Share Repurchases, Redemptions and Conversions

Overview

The Aon Ireland Constitution provides that Aon Ireland may purchase its own shares and redeem outstanding redeemable shares. Under Irish law, shares can only be purchased or redeemed out of (i) distributable profits or (ii) the proceeds of a new issuance of shares made for the purpose of such purchase or redemption. Under the Irish Companies Act, a company may purchase its own shares either (i) on-market on a recognized stock exchange, which includes the NYSE, or (ii) off-exchange (i.e., other than on a recognized stock exchange).

For Aon Ireland to make on-market purchases of its shares, Aon Ireland's shareholders must provide general authorization to Aon Ireland to do so by way of an ordinary resolution. For so long as such general authority is in force, no additional shareholder authority for a particular on-market purchase is required. Such authority can be given for a maximum period of five years before it is required to be renewed and must specify (i) the maximum number of shares that may be purchased and (ii) the maximum and minimum prices that may be paid for the shares, either by specifying particular sums or providing a formula.

For an off-exchange purchase, the proposed purchase contract must be authorized by special resolution of Aon Ireland's shareholders before being entered into.

Separately, Aon Ireland can redeem (as opposed to purchase) its redeemable shares once permitted to do so by the Aon Ireland Constitution (without the requirement for additional shareholder authority). The Aon Ireland Constitution provides that, unless Aon Ireland's board of directors determines otherwise, any share of Aon Ireland that Aon Ireland has agreed to acquire shall be automatically converted into a redeemable share of Aon Ireland. Accordingly, for purposes of the Irish Companies Act, unless Aon Ireland's board of directors determines otherwise, the acquisition of shares of Aon Ireland by Aon Ireland will technically be effected as a redemption of such shares. If the Aon Ireland Constitution did not contain such provision, the acquisition of shares of Aon Ireland by Aon Ireland would need to be effected as an on-market or off-exchange purchase, as described above.

Repurchased and redeemed shares may be cancelled or held as treasury shares, provided that the nominal value of treasury shares held by Aon Ireland at any time must not exceed 10% of Aon Ireland's company capital (consisting of the aggregate of all amounts of nominal value plus premium paid for shares of Aon Ireland, plus certain other sums that may be credited as such).

Purchases by Subsidiaries

Under Irish law, a subsidiary of Aon Ireland may purchase shares of Aon Ireland either on-market or off-exchange, provided such purchases are authorized by Aon Ireland's shareholders as described above. The redemption option is not available to a subsidiary of Aon Ireland. The number of shares of Aon Ireland held by Aon Ireland's subsidiaries at any time will count as treasury shares and will be included in any calculation of the 10% permitted treasury share threshold described above. While a subsidiary holds any shares of Aon Ireland, it cannot exercise voting rights in respect of those shares. The acquisition of shares of Aon Ireland by a subsidiary must be funded out of distributable profits of the subsidiary.

Under Irish law, Aon Ireland cannot exercise any voting rights in respect of any treasury shares. Treasury shares can either be held in treasury, re-issued on-market or off-exchange or cancelled. Depending on the circumstances of their acquisition, treasury shares may be held indefinitely or may be required to be cancelled after one or three years. The reissuance of treasury shares must be made pursuant to a valid and subsisting shareholder authority granted by way of a special resolution.

Share Repurchase Program

Aon Ireland's board of directors has authorized a program for Aon Ireland to repurchase Aon Ireland Shares. At December 31, 2022, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $6.0 billion.

As noted above, because repurchases of shares of Aon Ireland by Aon Ireland will technically be effected as a redemption of those shares pursuant to the Aon Ireland Constitution unless Aon Ireland's board of directors determines otherwise, such repurchases may be made whether or not the NYSE is a "recognized stock exchange" and shareholder approval for such repurchases will not be required.

Liens on Shares, Calls on Shares and Forfeiture of Shares

The Aon Ireland Constitution provides that Aon Ireland will have a first and paramount lien on every share for all moneys, whether currently due or not, payable in respect of such share. Subject to the terms of their allotment, Aon Ireland's board of directors may call for any unpaid amounts in respect of any shares to be paid, and if payment is not made, the shares shall be subject to forfeiture. The provision is a standard inclusion in the constitution of an Irish public limited company such as Aon Ireland and will only be applicable to shares of Aon Ireland that have not been fully paid-up.

Consolidation and Subdivision

Aon Ireland may, by ordinary resolution, consolidate all or any of its share capital into shares of larger nominal value, or subdivide all or any of its share capital into shares of smaller nominal value, than are fixed by the Aon Ireland Constitution.

Reduction of Share Capital

Aon Ireland may, by ordinary resolution, effect a reduction in its authorized but unissued share capital by cancelling unissued shares. Aon Ireland may also, by special resolution and subject to confirmation by the High Court of Ireland, reduce or cancel its issued share capital in any way permitted by the Irish Companies Act.

Annual General Meetings

As a matter of Irish law, Aon Ireland is required to hold an annual general meeting each calendar year, at an interval of no greater than 15 months from the previous annual general meeting and no more than nine months after Aon Ireland's financial year-end.

In addition to any SEC mandated resolutions, the business of Aon Ireland's annual general meeting is required to include: (i) the consideration of Aon Ireland's statutory financial statements; (ii) the review by Aon Ireland's shareholders of Aon Ireland's affairs; (iii) the election and reelection of Aon Ireland's board of directors in accordance with the Aon Ireland Constitution; (iv) the appointment or reappointment of the Irish statutory auditors; (v) the authorization of Aon Ireland's board of directors to approve the remuneration of the Irish statutory auditors; and (vi) the declaration of dividends (other than interim dividends).

Extraordinary General Meetings

As provided under Irish law, extraordinary general meetings may be convened:

•    by Aon Ireland's board of directors;

•    on the requisition of Aon Ireland's members holding not less than 10% of the paid-up share capital of Aon Ireland carrying voting rights;

•    on the requisition of Aon Ireland's auditors; and

•    in exceptional cases, by court order.

Extraordinary general meetings are typically held for the purpose of approving shareholder resolutions as may be required from time to time between annual general meetings. At any extraordinary general meeting only such business shall be conducted as is set forth in the notice thereof.

In the case of an extraordinary general meeting convened on the requisition of Aon Ireland's members, the proposed purpose of the meeting must be set forth in the requisition notice. Upon receipt of any such valid requisition notice, Aon Ireland's board of directors has 21 days to convene an extraordinary general meeting to vote on the matters set forth in the requisition notice. Such meeting must be held within two months of the receipt by Aon Ireland of the requisition notice. If Aon Ireland's board of directors does not convene the meeting within such 21-day period, the requisitioning members, or any of them representing more than one half of the total voting rights of all of them, may themselves convene an extraordinary general meeting, which meeting must be held within three months of the receipt by Aon Ireland of the requisition notice.

If Aon Ireland's board of directors becomes aware that Aon Ireland's net assets are half or less of the amount of Aon Ireland's called-up share capital, it must convene an extraordinary general meeting no later than 28 days after the earliest date that fact is known to any director for the purpose of considering whether any, and if so what, measures should be taken to deal with the situation (the meeting to be held within 56 days of that earliest date).

Notice of General Meetings

Irish law requires that notice of an annual or extraordinary general meeting must be given to all of Aon Ireland's members, to Aon Ireland's auditors and to Aon Ireland's directors and secretary. The Aon Ireland Constitution provides for the minimum statutory notice periods of 21 clear days' notice in writing for an annual general meeting or an extraordinary general meeting to approve a special resolution and 14 days' notice in writing for any other extraordinary general meeting.

Quorum for General Meetings

The Aon Ireland Constitution provides that no business shall be transacted at any general meeting unless a quorum is present. Holders who together represent at least a majority of the voting rights of all the shareholders entitled to vote, present in person or by proxy, at a general meeting, shall constitute a quorum.

Voting

The Aon Ireland Constitution provides that each of Aon Ireland's members is entitled to one vote for each share of Aon Ireland that he or she holds as of the record date for the meeting. Neither Irish law nor any of provision of the Aon Ireland Constitution places limitations on the rights of nonresident or foreign owners to hold shares of Aon Ireland or vote the rights attaching thereto.

Except where a greater majority is required by the Irish Companies Act or otherwise prescribed by the Aon Ireland Constitution, any question, business or resolution proposed at any general meeting shall be decided by an ordinary resolution.

At any of Aon Ireland's general meetings, all resolutions will be decided on a poll.

Irish law requires approval of certain matters by special resolution of Aon Ireland Shareholders at a general meeting. Examples of matters requiring special resolutions include:

•    amending the Aon Ireland Constitution;

•    approving a change of Aon Ireland's name;

•    authorizing the entering into of a guarantee or provision of security in connection with a loan, quasi-loan or credit transaction to a director or connected person of a director;

•    opting out of preemption rights on the issuance of new shares;

•    re-registration of Aon Ireland from a public limited company to a private limited company;

•    variation of class rights attaching to classes of shares (where the Aon Ireland Constitution does not provide otherwise);

•    repurchase of Aon Ireland's shares off-exchange;

•    reduction of Aon Ireland's issued share capital;

•    sanctioning a compromise/scheme of arrangement;

•    resolving that Aon Ireland be wound-up by the Irish courts;

•    resolving in favor of members' voluntary winding-up; and

•    setting the re-issue price of treasury shares.

Variation of Rights Attaching to a Class or Series of Shares

As a matter of Irish law, unless the Aon Ireland Constitution provides otherwise (which it does not), any variation of class rights attaching to Aon Ireland's issued shares must be approved (i) in writing by the holders of at least 75% of the issued shares in that class or (ii) with the sanction of a special resolution passed at a separate general meeting of the holders of the shares of that class, but not otherwise.

Inspection of Books and Records

Under Irish law, members have the right to:

•    receive a copy of the Aon Ireland Constitution;

•    inspect and obtain copies of the minutes of Aon Ireland's general meetings and resolutions;

•    inspect and receive a copy of the register of members, register of directors and secretaries, register of directors' interests and certain other statutory registers maintained by Aon Ireland;

•    receive copies of Aon Ireland's statutory financial statements together with the directors' and auditors' reports thereon for the most recent financial year; and

•    receive copies of the balance sheets of any of Aon Ireland's subsidiaries that have previously been produced to an annual general meeting of such subsidiary in the preceding ten years.

Acquisitions

Irish law recognizes the concept of a statutory merger in three situations: (i) a domestic merger where an Irish private limited company merges with another Irish company (which is not a public limited company) under Part 9 of the Irish Companies Act; (ii) a domestic merger where an Irish public limited company merges with another Irish company under Part 17 of the Irish Companies Act; and (iii) a cross-border merger where an Irish company merges with another company based in the EEA under the European Communities (Cross Border Merger) Regulations 2008 of Ireland.

Under Irish law and subject to applicable U.S. securities laws and NYSE rules and regulations, where Aon Ireland proposes to acquire another company, approval of Aon Ireland's shareholders will not be required unless effected as a direct domestic merger or direct cross-border merger as referred to above. Under Irish law, where another company proposes to acquire Aon Ireland, the requirement of the approval of Aon Ireland's shareholders will depend on the method of acquisition.

Takeover Offer

Under a takeover offer, the bidder will make a general offer to the target shareholders to acquire their shares. The offer must be conditional on the bidder acquiring, or having agreed to acquire (pursuant to the offer, or otherwise) securities conferring more than 50% of the voting rights of the target. The bidder may require any remaining shareholders to transfer their shares on the terms of the offer (i.e., a "squeeze out") if it has acquired, pursuant to the offer, not less than a specific percentage of the target shares to which the offer relates. The percentage for companies listed on regulated markets in the EEA is 90%. As Aon Ireland is not listed on an EEA regulated market (NYSE only), the relevant applicable percentage for Aon Ireland is 80%. Dissenting shareholders have the right to apply to the High Court of Ireland for relief.

Scheme of Arrangement

A scheme of arrangement is a statutory procedure which can be utilized to acquire an Irish company. A scheme of arrangement involves the target company putting an acquisition proposal to its shareholders, which can be (i) a transfer scheme, pursuant to which their shares are transferred to the bidder in return for the relevant consideration or (ii) a cancellation scheme, pursuant to which their shares are cancelled in return for the relevant consideration, with the result in each case that the bidder will become the 100% owner of the target company. A scheme of arrangement requires the approval of a majority in number of the shareholders of each class, representing at least 75% of the shares of each class, present and voting, in person or by proxy, at a general, or relevant class, meeting of the target company. The scheme also requires the sanction of the High Court of Ireland. Subject to the requisite shareholder approval and sanction of the High Court of Ireland, the scheme will be binding on all shareholders. Dissenting shareholders have the right to appear at the High Court of Ireland hearing and make representations in objection to the scheme.

Statutory Merger

It is possible for Aon Ireland to be acquired by way of a domestic or cross-border statutory merger, as described above. Such mergers must be approved by a special resolution of Aon Ireland's shareholders. If the consideration being paid to Aon Ireland's shareholders is not entirely cash, dissenting shareholders may be entitled to require that their shares be acquired for cash.

Appraisal Rights

Irish law generally does not provide for "appraisal rights." However, it does provide for dissenters' rights in certain situations, as described below.

Under a tender or takeover offer, the bidder may require any remaining shareholders to transfer their shares on the terms of the offer (i.e., a "squeeze out") if it has acquired, pursuant to the offer, not less than 80% of the target shares to which the offer relates (in the case of a company that is not listed on an EEA regulated market). Dissenting shareholders have the right to apply to the High Court of Ireland for relief.

A scheme of arrangement which has been approved by the requisite shareholder majority and sanctioned by the High Court of Ireland will be binding on all shareholders. Dissenting shareholders have the right to appear at the High Court of Ireland hearing and make representations in objection to the scheme.

Under the European Communities (Cross-Border Mergers) Regulations 2008 governing the merger of an Irish public limited company such as Aon Ireland and a company incorporated in the EEA, a shareholder (i) who voted against the special resolution approving the merger or (ii) of a company in which 90% of the shares are held by the other party to the merger, has the right to request that the company acquire his or her shares for cash at a price determined in accordance with the share exchange ratio set forth in the merger agreement.

Similar rights apply in the case of a merger of an Irish public limited company into another company to which the provisions of the Irish Companies Act apply.

Disclosure of Interests in Shares

Under the Irish Companies Act, there is a notification requirement for persons who acquire or cease to be interested in 3% of Aon Ireland's voting share capital, or any class thereof. Under the Irish Companies Act, "interested" is broadly defined and includes direct and indirect holdings, beneficial interests and, in some cases, derivative interests. Furthermore, a person's interests are aggregated with the interests of certain related persons and entities (including controlled companies). A person must notify Aon Ireland if, as a result of a transaction, that person will be interested in 3% or more of Aon Ireland's shares or if, as a result of a transaction, a person who was interested in more than 3% of Aon Ireland's shares ceases to be so interested. Where a person is interested in more than 3% of Aon Ireland's shares, any alteration of his or her interest that brings his or her total holding through the nearest whole percentage number, whether an increase or a reduction, must be notified to Aon Ireland.

The relevant percentage figure is calculated by reference to the aggregate nominal value of Aon Ireland's shares in which the person is interested as a proportion of the entire nominal value of Aon Ireland's issued ordinary share capital. Where the percentage level of the person's interest does not amount to a whole percentage, this figure may be rounded down to the previous whole number. All such disclosures should be notified to Aon Ireland within five business days of the transaction or the alteration that gave rise to the notification requirement.

Where a person fails to comply with the notification requirements described above, no right or interest of any kind whatsoever in respect of any shares of Aon Ireland held by such person shall be enforceable by such person, whether directly or indirectly, by action or legal proceeding. However, a person so affected may apply to the High Court of Ireland for relief.

In addition to the above disclosure requirement, under the Irish Companies Act, Aon Ireland may, by notice in writing, require a person whom it knows or has reasonable cause to believe, to be, or at any time during the three years immediately preceding the date on which such notice is issued, to have been, interested in shares comprised in Aon Ireland's share capital: (i) to indicate whether or not it is the case; and (ii) where such person holds, or has during that time held, an interest in Aon Ireland's shares, to give such further information as Aon Ireland may require, including particulars of such person's own past or present interests in the shares. Any information given in response to the notice is required to be given in writing within such reasonable time as Aon Ireland may specify in the notice.

Where such a notice is served by Aon Ireland on a person who is or was interested in Aon Ireland's shares and that person fails to give Aon Ireland any of the requested information within the reasonable time specified, Aon Ireland may apply to the High Court of Ireland for an order directing that the affected shares be made subject to certain restrictions. Under the Irish Companies Act, the restrictions that may be placed on the shares by the High Court of Ireland are as follows:

•    any transfer of those shares, or, in the case of unissued shares, any transfer of the right to be issued

•    with shares and any issue of shares, shall be void;

•    no voting rights shall be exercisable in respect of those shares;

•    no further shares shall be issued in right of those shares or in pursuance of any offer made to the holder of those shares;

and

•    no payment shall be made of any sums due from Aon Ireland on those shares, whether in respect of

•    capital or otherwise.

Where the shares are subject to these restrictions, the High Court of Ireland may order the shares to be sold and may also direct that the shares shall cease to be subject to these restrictions.

Irish Takeover Rules

Aon Ireland is subject to the Irish Takeover Panel Act 1997, as amended (the "Irish Takeover Panel Act") and the Irish Takeover Panel Act, 1997, Irish Takeover Rules 2022 (the "Irish Takeover Rules"), which regulate the conduct of takeovers of, and certain other relevant transactions affecting, Irish public limited companies listed on certain stock exchanges, including the NYSE. The Irish Takeover Rules are administered by the Irish Takeover Panel, which has supervisory jurisdiction over such transactions. Among other matters, the Irish Takeover Rules operate to ensure that no offer is frustrated or unfairly prejudiced and, in the case of multiple bidders, that there is a level playing field.

A transaction in which a third party seeks to acquire 30% or more of the voting rights in Aon Ireland and any other acquisitions of securities of Aon Ireland will be governed by the Irish Takeover Panel Act and the Irish Takeover Rules and will be regulated by the Irish Takeover Panel. The "General Principles," and certain important aspects, of the Irish Takeover Rules are described below.

General Principles

The Irish Takeover Rules are built on the following General Principles, which will apply to any transaction regulated by the Irish Takeover Panel: (i) in the event of an offer, all holders of securities of the target company must be afforded equivalent treatment and, if a person acquires control of a company, the other holders of securities must be protected; (ii) the holders of securities of the target company must have sufficient time and information to enable them to reach a properly informed decision on the offer; where it advises the holders of securities, the board of directors of the target company must give its views on the effects of the implementation of the offer on employment, employment conditions and the locations of the target company's place of business; (iii) a target company's board of directors must act in the interests of the target company as a whole and must not deny the holders of securities the opportunity to decide on the merits of the offer; (iv) false markets must not be created in the securities of the target company, the bidder or any other company concerned by the offer in such a way that the rise or fall of the prices of the securities becomes artificial and the normal functioning of the markets is distorted; (v) a bidder can only announce an offer after ensuring that such bidder can fulfill in full the consideration offered, if such is offered, and after taking all reasonable measures to secure the implementation of any other type of consideration; (vi) a target company may not be hindered in the conduct of its affairs longer than is reasonable by an offer for its securities; and (vii) a "substantial acquisition" of securities, whether to be effected by one transaction or a series of transactions, shall take place only at an acceptable speed and shall be subject to adequate and timely disclosure.

Mandatory Bid

Under certain circumstances, a person who acquires shares or other voting securities of a company may be required under the Irish Takeover Rules to make a mandatory cash offer for the remaining outstanding voting securities of that company at a price not less than the highest price paid for the securities by the acquiror, or any parties acting in concert with the acquiror, during the previous 12 months. This mandatory bid requirement is triggered if an acquisition of securities would increase the aggregate holdings of an acquiror, including the holdings of any parties acting in concert with the acquiror, to securities representing 30% or more of the voting rights in a company, unless the Irish Takeover Panel otherwise consents. An acquisition of securities by a person holding, together with its concert parties, securities representing between 30% and 50% of the voting rights in a company would also trigger the mandatory bid requirement if, after giving effect to the acquisition, the percentage of the voting rights held by that person, together with its concert parties, would increase by 0.05% within a 12-month period. Any person, excluding any parties acting in concert with the holder, holding securities representing more than 50% of the voting rights in a company is not subject to these mandatory offer requirements in purchasing additional securities.

Voluntary Bid; Requirements to Make a Cash Offer and Minimum Price Requirements

If a person makes a voluntary offer to acquire a company's outstanding ordinary shares, the offer price must not be less than the highest price paid for the company's ordinary shares by the bidder or its concert parties during the three-month period prior to the commencement of the offer. The Irish Takeover Panel has the power to extend the "look back" period to 12 months if it, taking into account the General Principles, believes it is appropriate to do so.

If the bidder or any of its concert parties has acquired shares of Aon Ireland (i) during the 12-month period prior to the commencement of the offer period that represents more than 10% of the shares of Aon Ireland or (ii) at any time after the commencement of the offer period, the offer must be in cash or accompanied by a full cash alternative and the price per share of Aon Ireland must not be less than the highest price paid by the bidder or its concert parties during, in the case of clause (i), the 12-month period prior to the commencement of the offer period or, in the case of (2), the offer period. The Irish Takeover Panel may apply this rule to a bidder who, together with its concert parties, has acquired less than 10% of the total number of shares of Aon Ireland in the 12- month period prior to the commencement of the offer period if the Irish Takeover Panel, taking into account the General Principles, considers it just and proper to do so. An offer period generally will commence on the date of the first announcement of the offer or proposed offer.

Substantial Acquisition Rules

The Irish Takeover Rules also govern substantial acquisitions of shares and other voting securities that restrict the speed at which a person may increase such person's holding of shares and rights over shares to an aggregate of between 15% and 30% of the voting rights of a company. Except in certain circumstances, an acquisition or series of acquisitions of shares or rights over shares representing 10% or more of the voting rights of a company is prohibited, if such acquisition(s), when aggregated with shares or rights already held, would result in the acquirer holding 15% or more but less than 30% of the voting rights of such company and such acquisitions are made within a period of seven days. These rules also require accelerated disclosure of acquisitions of shares or rights over shares relating to such holdings.

The Irish Takeover Rules include mandatory bid rules, share dealing restrictions and confidentiality objections.

Frustrating Action

Under the Irish Takeover Rules, Aon Ireland's board of directors is not permitted without either the consent of the Irish Takeover Panel or the approval of Aon Ireland's shareholders at a duly convened general meeting to take certain actions which might frustrate a takeover once Aon Ireland's board of directors has received an approach which may lead to an offer or has reason to believe an offer is, or may be, imminent.

Shareholder Rights Plan

Irish law does not expressly authorize or prohibit companies from issuing share purchase rights or adopting a shareholder rights plan as an anti-takeover measure, although the ability of Aon Ireland's board of directors to do so would be subject to its fiduciary duties and, during the course of an offer, the Irish Takeover Rules. However, there is no directly relevant Irish case law on this issue. The Aon Ireland Constitution allows Aon Ireland's board of directors to adopt a shareholder rights plan upon such terms and conditions as it deems expedient in the interests of Aon Ireland.

Issuance of Preference Shares

Aon Ireland's board of directors has the authority, without further action of Aon Ireland's shareholders for a period of five years from the date of adoption of the Aon Ireland Constitution (which occurred on March 31, 2020), but subject to its statutory and fiduciary duties and the requirements of Irish law, to issue up to 50,000,000 preference shares, in one or more series, and to fix the powers, preferences, rights and qualifications, limitations or restrictions thereof. The issuance of preference shares on various terms could adversely affect Aon Ireland's shareholders. The potential issuance of preference shares may discourage bids for shares of Aon Ireland at a premium over the market price, may adversely affect the market price of shares of Aon Ireland and may discourage, delay or prevent a change of control of Aon Ireland.

Corporate Governance

The Aon Ireland Constitution delegates the management of Aon Ireland's business to Aon Ireland's board of directors. Aon Ireland's board of directors, in turn, is empowered to delegate any of its powers, authorities and discretions (with further power to sub-delegate) to any committee, consisting of such person or persons (whether directors or not) as it thinks fit, but regardless, Aon Ireland's board of directors will remain responsible, as a matter of Irish law, for the proper management of Aon Ireland's business and affairs. Committees may meet and adjourn as they determine to be proper. Unless otherwise determined by Aon Ireland's board of directors, the quorum necessary for the transaction of business at any committee meeting shall be a majority of the members of such committee then in office.

Legal Name; Fiscal Year; Registered Office

Aon Ireland was incorporated in Ireland as a private limited company on May 23, 2017 under the name Linzicon Limited. The name of Aon Ireland was changed to Aon Limited on November 5, 2019. Aon Ireland was re-registered as a public company and renamed Aon plc on March 18, 2020. Aon Ireland's financial year ends on December 31, and Aon Ireland's registered office is at Metropolitan Building, James Joyce Street, Dublin 1, Ireland D01 K0Y8.

Directors

Number of Directors

The Aon Ireland Constitution provides that the number of directors of Aon Ireland shall be as Aon Ireland's board of directors may determine from time to time and that as of the date of adoption of the Aon Ireland Constitution shall be no more than 21 and no less than seven. There are currently 12 directors of Aon Ireland.

Appointment of Directors

Both Aon Ireland's shareholders and Aon Ireland's board of directors have the power to appoint a person as a director of Aon Ireland, either to fill a vacancy or as an additional position, by simple majority resolution.

Election of Directors

Under the Aon Ireland Constitution, directors of Aon Ireland shall stand for election or re-election at each annual general meeting. Each director of Aon Ireland shall hold office until his or her successor is elected or until his or her earlier resignation or removal in accordance with the Aon Ireland Constitution or, otherwise, pursuant to the Irish Companies Act. Where the appointment of a director is contested (i.e., there is a shareholder meeting at which it is proposed to vote on resolutions for the appointment of directors and the total number of proposed directors exceeds the total number of directors to be appointed at such shareholder meeting), the Aon Ireland Constitution provides "plurality voting" applicable to contested elections of directors (i.e., the directors with the greatest number of votes are elected in descending order until the number of directors to be appointed at such meeting is satisfied).

Removal of Directors

Under the Irish Companies Act, Aon Ireland's shareholders may remove a director of Aon Ireland without cause by ordinary resolution, provided that at least 28 clear days' notice of such resolution is given to Aon Ireland and that Aon Ireland's shareholders comply with all relevant procedural requirements. The power of removal is without prejudice to any claim for damages for breach of contract (e.g., employment contract) the director of Aon Ireland may have against Aon Ireland in respect of his or her removal. The Aon Ireland Constitution separately provides that Aon Ireland's shareholders can remove a director of Aon Ireland without cause by ordinary resolution. No special notice of the resolution to remove a director under the Aon Ireland Constitution need be given, and such director does not have a right to make reasonable written representations as he or she would under the statutory removal procedure.

Duration; Dissolution; Rights Upon Liquidation

Aon Ireland's duration of existence is unlimited. Aon Ireland may be dissolved and wound-up at any time by way of a members' voluntary winding-up or a creditors' winding-up. In the case of a members' voluntary winding-up, a special resolution is required. Aon Ireland may also be dissolved by way of court order on the application of a creditor or by the Companies Registration Office as an enforcement measure where Aon Ireland has failed to file certain returns.

The rights of Aon Ireland's shareholder to a return on Aon Ireland's assets upon dissolution or winding-up, following the settlement of all claims of creditors, may be prescribed in the Aon Ireland Constitution. If the Aon Ireland Constitution contains no specific provisions in respect of a dissolution or winding-up, then, subject to the priorities of any creditors, the assets will be distributed to Aon Ireland's shareholders in proportion to the paid-up nominal value of the shares of Aon Ireland held.

Stock Exchange Listing

The Aon Ireland Shares were approved for listing on the NYSE and began trading on March 31, 2020 under the symbol "AON," the same symbol under which the Class A ordinary shares of Aon UK previously listed. Aon Ireland has no current plans to list its shares on any other securities exchange, including Euronext Dublin.

No Liability for Further Calls or Assessments

The shares of Aon Ireland issued in the Reorganization were duly and validly issued and credited as fully paid-up.

Transfer and Registration of Shares

Aon Ireland's register of members, which Aon Ireland is required to maintain under the Irish Companies Act, will be maintained by Aon Ireland's transfer agent. Registration in the register of members is determinative of membership. A person who holds shares of Aon Ireland beneficially will not have his or her name entered in Aon Ireland's register of members, and for the purposes of Irish law, will not be the registered holder of such shares. Instead, any depository or other nominee whose name is entered in Aon Ireland's register of members will be the registered holder of such shares. Accordingly, a transfer of shares of Aon Ireland from a person who holds such shares beneficially to a person who also holds such shares beneficially through a depository or other nominee will not be registered in Aon Ireland's register of members, as the depository or other nominee will remain the registered holder of such shares.

A written instrument of transfer generally is required under Irish law in order to effect a transfer of the registered interest in shares of Aon Ireland and to update Aon Ireland's register of members. Accordingly, a written instrument of transfer will be required for transfers of shares of Aon Ireland: (i) from a registered holder of shares to any other person; (ii) from a person who holds shares beneficially (where the registered interest is held by the depository or other nominee) to another person who wishes, on transfer, to be registered as the registered holder of such shares; (iii) from a person who holds shares beneficially to another person who also wishes, on transfer, to hold such shares beneficially but where the transfer involves a change in the depository or other nominee that is the registered holder of such shares; or (iv) by a registered holder into his or her own broker account (or vice versa).

Such instruments of transfer may give rise to Irish stamp duty, which must be paid prior to registration of the transfer in Aon Ireland's register of members. However, a registered holder may transfer shares of Aon Ireland into his or her own broker account (or vice versa) without giving rise to Irish stamp duty, provided that there is no change in the beneficial ownership of such shares as a result of the transfer and the transfer is not made in contemplation of a subsequent sale of such shares to a third party.

Any transfer of shares of Aon Ireland that is subject to Irish stamp duty will not be registered in the name of the transferee unless an instrument of transfer is duly stamped and provided to the transfer agent. Aon Ireland, in its absolute discretion and insofar as the Irish Companies Act or any other applicable law permits, may, or may provide that a subsidiary of Aon Ireland will, pay Irish stamp duty arising on a transfer of shares of Aon Ireland on behalf of the transferee of such shares. If stamp duty resulting from the transfer of shares of Aon Ireland which would otherwise be payable by the transferee is paid by Aon Ireland or any of its subsidiaries on behalf of the transferee, then in those circumstances, Aon Ireland will, on its behalf or on behalf of its subsidiary (as the case may be), be entitled to: (i) seek reimbursement of the stamp duty from the transferee or the transferor (at its discretion); (ii) set-off the stamp duty against any dividends payable to the transferee of those shares; and (iii) claim a first and permanent lien on the shares on which stamp duty has been paid by Aon Ireland or its subsidiary for the amount of stamp duty paid. Aon Ireland's lien shall extend to all dividends paid on those shares.

The Aon Ireland Constitution delegates to Aon Ireland's secretary (or any person that the secretary nominates) the authority to execute an instrument of transfer on behalf of a transferor. To help ensure that Aon Ireland's register of members is regularly updated to reflect trading of shares of Aon Ireland occurring through electronic systems, Aon Ireland intends to regularly produce such instruments of transfer as may be required to effect any transfers of registered interests in shares. These may involve transactions for which Aon Ireland pays stamp duty, subject to the reimbursement and set-off rights described above. In the event that Aon Ireland notifies one or both of the parties to a share transfer that it believes stamp duty is required to be paid in connection with such transfer and that Aon Ireland will not pay such stamp duty, such parties may either themselves arrange for the execution of the required instrument of transfer (and may request a form of instrument of transfer from Aon Ireland for this purpose) or request that Aon Ireland execute an instrument of transfer on behalf of the transferring party in a form determined by Aon Ireland. In either event, if the parties to the share transfer have the instrument of transfer duly stamped (to the extent required) and then provide it to the transfer agent, the transferee named therein will be registered as the registered holder of the relevant shares in Aon Ireland's register of members (subject to the matters described below).

The registration of transfers may be suspended by Aon Ireland's board of directors at such times and for such periods, not exceeding in the whole 30 days in each year, as it may from time to time determine.

DESCRIPTION OF DEBT SECURITIES AND GUARANTEES

Set forth below is a summary of the material terms of the debt securities and guarantees of Aon plc, an Irish public limited company ("Aon Ireland"), Aon Global Limited (f/k/a Aon plc), a public limited company formed under the laws of England and Wales ("Aon UK"), Aon Corporation, a Delaware corporation ("Aon Delaware"), and Aon Global Holdings plc (“AGH”), a public limited company formed under the laws of England and Wales. In this section, references to "holders" mean those who own debt securities and the related guarantees registered in their own names, on the books that the appropriate registrar for Aon Ireland, Aon UK, AGH and/or Aon Delaware, as the case may be, maintains for this purpose, and not those who own beneficial interests in debt securities and the related guarantees registered in "street name" or in debt securities and the related guarantees issued in book-entry form and held through one or more depositaries.

This is a description of certain general terms and provisions of the debt securities that Aon Ireland may offer (the “Aon Ireland debt securities"), Aon UK may offer (the "Aon UK debt securities"), AGH may offer (the “AGH debt securities”), Aon Delaware may offer (the "Aon Delaware debt securities"), or that any combination of Aon Ireland, Aon UK, AGH or Aon Delaware may offer as co-issuers (the “co-issued debt securities”) pursuant to a prospectus. When Aon Ireland, Aon UK, AGH, and/or Aon Delaware offer to sell a particular series of debt securities, Aon Ireland, Aon UK, AGH and/or Aon Delaware will describe the specific terms of that series in one or more prospectus supplements. Aon Ireland, Aon UK, AGH and/or Aon Delaware will also indicate in an applicable prospectus supplement the extent to which the general terms and provisions described in the prospectus apply to a particular series of debt securities.

Aon Ireland may issue Aon Ireland debt securities or co-issued debt securities under either: (1) a senior indenture (the "Aon Ireland senior indenture"), among Aon Ireland, as issuer or co-issuer, either Aon UK, Aon Delaware or AGH, as co-issuer, Aon UK, Aon Delaware and/or AGH to the extent not acting as co-issuer, as guarantors (the "Aon Ireland senior debt guarantors") in respect of certain series of Aon Ireland senior debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Aon Ireland senior debt trustee"); or (2) a subordinated indenture (the "Aon Ireland subordinated indenture") among Aon Ireland, as issuer, Aon UK, Aon Delaware and/or AGH, as guarantors (the "Aon Ireland subordinated debt guarantors" and, together with the Aon Ireland senior debt guarantors, the "Aon Ireland guarantors") in respect of certain series of Aon Ireland subordinated debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Aon Ireland subordinated debt trustee" and, together with the Aon Ireland senior debt trustee, the "Aon Ireland trustee"). Any Aon Ireland debt securities or co-issued debt securities that Aon Ireland issues or co-issues under the Aon Ireland senior indenture will constitute unsubordinated debt of Aon Ireland ("Aon Ireland senior debt securities") and will rank senior to any Aon Ireland debt securities that Aon Ireland issues under the Aon Ireland subordinated indenture ("Aon Ireland subordinated debt securities"). Any guarantee that Aon Delaware, Aon UK and/or AGH, as the Aon Ireland senior debt guarantors, issues under the Aon Ireland senior indenture will constitute an unsubordinated obligation of Aon Delaware, Aon UK and/or AGH, as applicable (each, an "Aon Ireland senior debt guarantee"), and will rank senior to any guarantee that Aon Delaware, Aon UK and/or AGH, as the Aon Ireland subordinated debt guarantors, issue under the Aon Ireland subordinated indenture (each, an "Aon Ireland subordinated debt guarantee" and, together with the Aon Ireland senior debt guarantees, the "Aon Ireland debt guarantees").

Aon UK may issue Aon UK debt securities or co-issued debt securities under a senior indenture (the "Aon UK senior indenture"), among Aon UK, as issuer or co-issuer, either Aon Delaware, Aon Ireland or AGH, as co-issuer, Aon Ireland, Aon Delaware and/or AGH to the extent not acting as co-issuer, as guarantors (the "Aon UK senior debt guarantors") in respect of certain series of Aon UK senior debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Aon UK senior debt trustee"). Any Aon UK debt securities or co-issued debt securities that Aon UK issues or co-issues under the Aon UK senior indenture will constitute unsubordinated debt of Aon UK ("Aon UK senior debt securities"). Any guarantee that Aon Delaware, Aon Ireland and/or AGH, as the Aon UK senior debt guarantors, issues under the Aon UK senior indenture will constitute an unsubordinated obligation of Aon Delaware, Aon Ireland and/or AGH, as applicable (each, an "Aon UK senior debt guarantee").

Aon Delaware may issue Aon Delaware debt securities or co-issued debt securities under either: (1) a senior indenture (the "Aon Delaware senior indenture"), among Aon Delaware, as issuer or co-issuer, either Aon UK, Aon Ireland or AGH, as co-issuer, Aon Ireland, Aon UK and/or AGH to the extent not acting as co-issuer, as guarantors (the "Aon Delaware senior debt guarantors") in respect of certain series of Aon Delaware senior debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Aon Delaware senior debt trustee"); or (2) a subordinated indenture (the "Aon Delaware

subordinated indenture") among Aon Delaware, as issuer, Aon UK, Aon Ireland and/or AGH, as guarantors (the "Aon Delaware subordinated debt guarantors" and, together with the Aon Delaware senior debt guarantors, the "Aon Delaware guarantors") in respect of certain series of Aon Delaware subordinated debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Aon Delaware subordinated debt trustee" and, together with the Aon Delaware senior debt trustee, the "Aon Delaware trustee"). Any Aon Delaware debt securities or co-issued debt securities that Aon Delaware issues or co-issues under the Aon Delaware senior indenture will constitute unsubordinated debt of Aon Delaware ("Aon Delaware senior debt securities") and will rank senior to any Aon Delaware debt securities that Aon Delaware issues under the Aon Delaware subordinated indenture ("Aon Delaware subordinated debt securities"). Any guarantee that Aon UK, Aon Ireland and/or AGH, as the Aon Delaware senior debt guarantors, issues under the Aon Delaware senior indenture will constitute an unsubordinated obligation of Aon UK, Aon Ireland and/or AGH, as applicable (each, an "Aon Delaware senior debt guarantee"), and will rank senior to any guarantee that Aon UK, Aon Ireland and/or AGH, as the Aon Delaware subordinated debt guarantors, issues under the Aon Delaware subordinated indenture (each, an "Aon Delaware subordinated debt guarantee" and, together with the Aon Delaware senior debt guarantees, the "Aon Delaware debt guarantees").

AGH may issue AGH debt securities or co-issued debt securities, under a senior indenture (the "AGH senior indenture"), among AGH, as issuer or co-issuer, either Aon UK, Aon Ireland or Aon Delaware, as co-issuer, Aon UK, Aon Ireland and/or Aon Delaware to the extent not acting as co-issuer, as guarantors (the "AGH senior debt guarantors") in respect of certain series of AGH senior debt securities (as defined below), and The Bank of New York Mellon Trust Company, N.A., as trustee (the "AGH senior debt trustee"). Any AGH debt securities or co-issued debt securities that AGH issues or co-issues under the AGH senior indenture will constitute unsubordinated debt of AGH ("AGH senior debt securities"). Any guarantee that Aon UK, Aon Ireland or Aon Delaware, as the AGH senior debt guarantors, issues under the AGH senior indenture will constitute an unsubordinated obligation of Aon UK, Aon Ireland and/or Aon Delaware, as applicable (each, an "AGH senior debt guarantee").

In this description, the Aon Ireland debt securities, the Aon UK debt securities, the AGH debt securities, the Aon Delaware debt securities, and the co-issued debt securities are sometimes referred to together as the "debt securities," the Aon Ireland senior debt securities, the Aon UK senior debt securities, the AGH senior debt securities and the Aon Delaware senior debt securities are sometimes referred to together as the "senior debt securities," the Aon Ireland subordinated debt securities and the Aon Delaware subordinated debt securities are sometimes referred together as the "subordinated debt securities," the Aon Ireland senior indenture, the Aon UK senior indenture, the AGH senior indenture and the Aon Delaware senior indenture are sometimes referred to together as the "senior indentures," the Aon Ireland subordinated indenture and the Aon Delaware subordinated indenture are sometimes referred to together as the "subordinated indentures," the senior indentures and the subordinated indentures are sometimes referred to together as the "indentures," the Aon Ireland debt guarantees, the Aon UK senior debt guarantees, the AGH senior debt guarantees and the Aon Delaware debt guarantees are sometimes referred to together as the "guarantees," each of Aon Ireland, Aon UK, AGH and Aon Delaware, in each case in its capacity as issuer or co-issuer of debt securities, is sometimes referred to as an "issuer," each of the Aon Ireland debt guarantors, the Aon UK debt guarantors, the AGH debt guarantors and the Aon Delaware debt guarantors is sometimes referred to as a "guarantor," each of the Aon Ireland senior trustee, the Aon UK senior trustee, the AGH senior trustee and the Aon Delaware senior trustee is sometimes referred to as a "senior trustee," each of the Aon Ireland subordinated trustee and the Aon Delaware subordinated trustee is sometimes referred to as a "subordinated trustee," and each of the senior trustee and the subordinated trustee is sometimes referred to as the "trustee."

Each series of debt securities will be issued under the terms of an amendment or supplement to the applicable indenture that takes the form of a supplemental indenture or an officers' certificate delivered under the authority of resolutions adopted by the board of directors of the issuer and the terms of that indenture. The terms of any debt securities and, if applicable, the guarantees will include those stated in the applicable indenture and those made part of that indenture by reference to the Trust Indenture Act of 1939 (the "Trust Indenture Act"). The debt securities will be subject to all those terms, and prospective purchasers and holders of debt securities and guarantees are referred to the applicable indenture and the Trust Indenture Act for a statement of those terms.

The following summaries of various provisions of the debt securities, the indentures and the guarantees are not complete. They do not describe certain exceptions and qualifications contained in the debt securities, the indentures and the guarantees, and are qualified in their entirety by reference to the provisions of the debt securities, the indentures and the guarantees. Unless otherwise indicated, capitalized terms have the meanings assigned to them in the applicable indenture.

An applicable prospectus supplement will specify the issuer, the co-issuer (if any), the guarantors, if any, whether the debt securities offered thereby will be senior or subordinated debt and whether the debt securities are to be guaranteed. The debt securities may be issued as part of units consisting of debt securities and other securities that Aon Ireland, Aon UK, AGH, and/or Aon Delaware may offer under the prospectus. If debt securities are issued as part of units of debt securities and other securities that Aon Ireland, Aon UK, AGH, and/or Aon Delaware may issue under the prospectus, an applicable prospectus supplement will describe any applicable material federal income tax consequences to holders.

General

The debt securities will be unsecured obligations of the applicable issuer. None of the indentures limit the amount of debt securities that the issuer may issue. Each indenture provides that the issuer may issue debt securities from time to time in one or more series.

The Aon Ireland senior debt securities and any Aon Delaware, AGH or Aon UK senior debt guarantee will be unsecured and unsubordinated obligations of Aon Ireland and will rank equally in right of payment with Aon Ireland's other unsecured and unsubordinated obligations. The Aon Ireland subordinated debt securities and any Aon Delaware subordinated debt guarantee will be subordinated obligations and will rank junior in right of payment, as more fully described in the applicable subordinated indenture, to Aon Ireland's senior indebtedness. Because Aon Ireland is a holding company, the holders of Aon Ireland debt securities and Aon Delaware debt guarantees may not receive assets of Aon Ireland subsidiaries in a liquidation or recapitalization until the claims of Aon Ireland's subsidiaries' creditors and any insurance policyholders (in the case of Aon Ireland's insurance subsidiaries) are paid, except to the extent that Aon Ireland may have recognized claims against such subsidiaries. In addition, certain regulatory laws limit some of Aon Ireland’s subsidiaries from making payments to Aon Ireland of dividends and on loans and other transfers of funds.

The Aon Delaware senior debt securities and any Aon Ireland, Aon UK or AGH senior debt guarantee will be unsecured and unsubordinated obligations of Aon Delaware and will rank equally in right of payment with Aon Delaware's other unsecured and unsubordinated obligations. The Aon Delaware subordinated debt securities and any Aon Ireland subordinated debt guarantee will be subordinated obligations and will rank junior in right of payment, as more fully described in the applicable subordinated indenture, to Aon Delaware's senior indebtedness. Because Aon Delaware is a holding company, the holders of Aon Delaware debt securities and Aon Ireland debt guarantees may not receive assets of Aon Delaware's subsidiaries in a liquidation or recapitalization until the claims of Aon Delaware's subsidiaries' creditors and any insurance policyholders (in the case of Aon Delaware's insurance subsidiaries) are paid, except to the extent that Aon Delaware may have recognized claims against such subsidiaries. In addition, certain regulatory laws limit Aon Delaware's subsidiaries from making payments to Aon Delaware of dividends and on loans and other transfers of funds.

An applicable prospectus supplement will describe the specific terms relating to the series of debt securities being offered. These terms will include some or all of the following:

•    the name of the issuer and, if appliable, the co-issuer of those debt securities and, if applicable, the name of the guarantor;

•    the title of the debt securities and whether the debt securities and, if applicable, the guarantee will be senior or subordinated;

•    the total principal amount of the debt securities;

•    whether the issuer will issue the debt securities in global form;

•    the maturity date or dates of the debt securities;

•    the interest rate or rates, if any (which may be fixed or variable), and, if applicable, the method used to calculate the interest rate;

•    the date or dates from which interest will accrue and on which interest will be payable and the date or dates used to determine the persons to whom interest will be paid;

•    whether those debt securities will be guaranteed;

•    the place or places where principal of, and any premium or interest on, the debt securities will be paid;

•    whether (and if so, when and under what terms and conditions) the debt securities may be redeemed by the issuer and/or the co-issuer, if applicable, at its or their option or at the option of the holders;

•    whether there will be a sinking fund;

•    if other than U.S. dollars and denominations of $2,000 or any multiple of $1,000, the currency or currencies or currency unit or currency units or composite currency and denomination in which the debt securities will be issued and in which payments will be made;

•    if other than the principal amount, the portion of the principal amount of the debt securities that the issuer will pay upon acceleration of the maturity date;

•    if the debt securities are not subject to defeasance by the issuer;

•    any deletions from, modifications of or additions to the events of default applicable to such debt securities;

•    whether the debt securities will be exchangeable for or convertible into other securities or property and the terms and conditions governing such exchange or conversion; and

•    any other terms of the debt securities being offered.

If an issuer denominates the purchase price of a series of debt securities in a non-U.S. dollar currency or currencies or a non-U.S. dollar currency unit or units, or if the principal of, any premium and interest on any series of debt securities is payable in a non-U.S. dollar currency or currencies or a non-U.S. dollar currency unit or units, an applicable prospectus supplement will describe any special U.S. federal income tax considerations.

The issuer will pay principal and any interest, premium and additional amounts in the manner, at the places and subject to the restrictions set forth in the applicable debt securities, the applicable indenture and any applicable prospectus supplement. The issuer will not impose a service charge for any transfer or exchange of debt securities, but it may require payment of a sum sufficient to cover any tax or other governmental charge that may be imposed.

Unless otherwise indicated in an applicable prospectus supplement, each issuer will issue debt securities in fully registered form, without coupons, in denominations of $2,000 or multiples of $1,000.

The issuer may offer to sell at a substantial discount below their stated principal amount, debt securities bearing no interest or interest at a rate that, at the time of issuance, is below the prevailing market rate. An applicable prospectus supplement will describe any special U.S. federal income tax considerations applicable to any of those discounted debt securities.

The issuer may offer to sell debt securities in which the principal or interest will be determined by reference to one or more currency exchange rates, commodity prices, equity indices or other factors. The principal amount or payment of interest applicable to those debt securities may be greater than or less than the amount of principal or interest otherwise payable, depending upon the value of the applicable currency, commodity, equity index or other factor on the date on which that principal or interest is due. An applicable prospectus supplement will describe the methods used to determine the amount of principal or interest payable on any date, the currencies, commodities, equity indices or other factors to which the amount payable on that date is linked and certain additional tax considerations applicable to those debt securities.

The indentures do not restrict Aon Ireland’s, Aon UK's, AGH’s or Aon Delaware's ability to incur unsecured indebtedness or, subject to the restrictions described in "-Consolidation and Merger," to engage in reorganizations, restructurings, mergers, consolidations or similar transactions that have the effect of increasing Aon Ireland, Aon UK's, AGH’s or Aon Delaware's indebtedness. Accordingly, unless an applicable prospectus supplement states otherwise, neither the debt securities nor any guarantees will contain any provisions that afford holders protection against an issuer or, if applicable, the guarantor incurring unsecured indebtedness or engaging in certain reorganizations or transactions. As a result, Aon Ireland, Aon UK, AGH and/or Aon Delaware could become highly leveraged.

Events of Default

With respect to any series of debt securities, "event of default" means any of the following:

•    failure to pay the principal of, or any premium on, any debt security of that series when due;

•    failure to pay the interest or any additional amount on any debt security of that series when due and such failure continues for 30 days;

•    if that series of debt securities is guaranteed, the cessation of the guarantee of any debt security of that series to be in full force and effect, the declaration that the guarantee of those debt securities is null and void and unenforceable, the finding that the guarantee of those debt securities is invalid or the denial by the guarantor of its liability under its guarantee of those debt securities (other than by reason of release of the guarantor in accordance with the terms of the applicable indenture);

•    failure by the issuer or, if applicable, the guarantor to comply with any of its other covenants or agreements contained in the applicable indenture and the continuation of that failure for 90 days after written notice of that failure is given to the issuer or, if applicable, the guarantor from the applicable trustee (or to the issuer and, if applicable, the guarantor and that trustee from the holders of at least 25% in principal amount of the outstanding debt securities of that series);

•    certain events of bankruptcy, insolvency or reorganization relating to the issuer or, if applicable, the guarantor;

•    if that series of debt securities is convertible or exchangeable into other securities or property, default in the delivery of any other securities or property, as applicable, when required to be delivered upon conversion or exchange of any debt security of that series, and continuance of such default for a period of 10 business days; and

•    any other event of default provided with respect to debt securities of that series that is described in an applicable prospectus supplement.

If there is a continuing event of default with respect to any outstanding series of debt securities, the applicable trustee or the holders of at least 25% of the outstanding principal amount of the debt securities of that series may require the issuer or, if applicable, the guarantor to pay immediately the principal (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) of and accrued and unpaid interest, if any, on all debt securities of that series. However, at any time after that trustee or the holders, as the case may be, declare that acceleration with respect to debt securities of any series, but before the applicable person has obtained a judgment or decree for payment of the money, the holders of a majority in principal amount of the outstanding debt securities of that series may, under certain conditions, cancel such acceleration if (i) all events of default (other than the non-payment of accelerated principal) with respect to debt securities of that series have been cured or (ii) all such events of default have been waived, each as provided in the applicable indenture. (Section 6.01 of the indentures) For information as to waiver of defaults, see "-Modification and Waiver." The particular provisions relating to acceleration of the maturity of a portion of the principal amount of such debt securities that are discount securities triggered by an event of default shall be described in an applicable prospectus supplement.

Each indenture provides that, subject to the duties of the applicable trustee to act with the required standard of care if there is a continuing event of default, the applicable trustee need not exercise any of its rights or powers under the indenture at the request or direction of any of the holders of debt securities, unless those holders have offered to the applicable trustee security or indemnity reasonably satisfactory to it. (Section 7.02 of the indentures) Subject to those provisions for security or indemnification of the applicable trustee and certain other conditions, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the applicable trustee or exercising any trust or power that trustee holds, in each case, with respect to the debt securities of that series. (Section 6.06 of the indentures)

No holder of any debt security of any series will have any right to institute any proceeding with respect to any indenture or for any remedy under the applicable indenture unless:

•    the applicable trustee has failed to institute the proceeding for 60 days after the holder has previously given that trustee written notice of a continuing event of default with respect to debt securities of that series;

•    the holders of at least 25% in principal amount of the outstanding debt securities of that series have made written request, and offered reasonable security or indemnity, to the applicable trustee to institute the proceeding as trustee; and

•    the applicable trustee has not received from the holders of a majority in principal amount of the outstanding debt securities of that series a direction inconsistent with that request.

However, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, and any premium or interest on, that debt security on or after the date or dates they are to be paid as expressed in or pursuant to that debt security and to institute suit for the enforcement of any such payment.

Each indenture provides that the applicable trustee shall provide notice to the holders of debt securities of any series within 90 days of the occurrence of any default with respect to debt securities of that series known to such trustee, except that the trustee need not provide holders of debt securities of any series notice of any default (other than the non-payment of principal or any premium, interest or additional amounts) if such default has been cured and the applicable trustee considers it in the interest of the holders of debt securities of that series not to provide that notice.

Consolidation and Merger

Each indenture provides that each of the issuer and the guarantor may consolidate with or merge or convert into, or convey, transfer or lease its properties or assets substantially as an entirety to, another person without the consent of any debt security holders if, along with certain other conditions set forth in the indentures:

•    the issuer or the guarantor, as the case may be, is the successor person; or

•    the successor person (if other than the issuer or the guarantor, as the case may be) formed by such consolidation or conversion or into which the issuer or the guarantor, as the case may be, merges or converts or which acquires or leases the assets of the issuer or the guarantor, as the case may be, substantially as an entirety;

•    in the case of Aon Delaware, is a corporation or other entity organized and existing under the laws of the United States, any state thereof or the District of Columbia; and

•    in the case of either Aon Ireland, Aon UK, AGH or Aon Delaware, expressly assumes by supplemental indenture the obligations of the issuer or the guarantor, as the case may be, in relation to the debt securities or the guarantees, as the case may be, and under the applicable indenture;

•    immediately after giving effect to such transaction, there is no event of default, and no event which, after notice or passage of time or both, would become an event of default; and

•    Aon Ireland, Aon UK, AGH or Aon Delaware, as the case may be, has delivered to the trustee an officers' certificate stating that the transaction complies with the conditions set forth in the applicable indenture.

It is possible that a merger, transfer, lease or other transaction could be treated for U.S. federal income tax purposes as a taxable exchange by the holders of debt securities or guarantees for new securities, which could result in holders of debt securities or guarantees recognizing taxable gain or loss for U.S. federal income tax purposes. A merger, transfer, lease or other transaction could also have adverse tax consequences to holders of debt securities or guarantees under other tax laws to which the holders are subject.

Payment of Additional Amounts

Payments made by the issuer or a paying agent, as applicable, on the debt securities, or in respect to the guarantees, will be made free and clear of and without withholding or deduction for or on account of any present or future income, stamp or other tax, duty, levy, impost, assessment or other governmental charge of any nature whatsoever imposed or levied by or on behalf of the government of the United Kingdom or the United States (each, a "Home Country Jurisdiction"), of any territory of a Home Country Jurisdiction or by any authority or agency therein or thereof having the power to tax ("Taxes"), unless the issuer or a paying agent is required to withhold or deduct Taxes by law.

If the issuer or a paying agent is required to withhold or deduct any amount for or on account of Taxes from any payment made with respect to the debt securities or the guarantees, the issuer will pay such additional amounts as may be necessary so that the net amount received by each beneficial owner (including additional amounts) after such withholding or deduction will not be less than the amount the beneficial owner would have received if the Taxes had not been withheld or deducted; provided that no additional amounts will be payable with respect to Taxes:

•    that would not have been imposed but for the existence of any present or former connection between such holder or beneficial owner of the debt securities or guarantees, as applicable (or between a fiduciary, settlor, beneficiary, member or shareholder of, or possessor of a power over, such holder or beneficial owner, if such holder or beneficial owner is an estate, trust, partnership or corporation), and such Home Country Jurisdiction or any political subdivision or territory or possession thereof or therein or area subject to its jurisdiction, including, without limitation, such holder or beneficial owner (or such fiduciary, settlor, beneficiary, member, shareholder or possessor) being or having been a citizen or resident thereof or treated as a resident thereof or domiciled thereof or a national thereof or being or having been present or engaged in trade or business therein or having or having had a permanent establishment therein;

•    that are estate, inheritance, gift, sales, transfer, personal property, wealth or similar taxes, duties, assessments or other governmental charges;

•    payable other than by withholding from payments of principal of and premium, if any, or interest, if any, on the debt securities or the guarantees, as applicable;

•    that would not have been imposed but for the failure of the applicable recipient of such payment to comply with any

certification, identification, information, documentation or other reporting requirement to the extent: such compliance is required by applicable law or administrative practice or an applicable treaty as a precondition to exemption from, or reduction in, the rate of deduction or withholding of such Taxes; and at least 30 days before the first payment date with respect to which such additional amounts shall be payable, Aon UK or Aon Delaware, as the case may be, has notified such recipient in writing that such recipient is required to comply with such requirement;

•    that would not have been imposed but for the presentation of the relevant debt security or guarantee (where presentation is required) for payment on a date more than 30 days after the date on which such payment became due and payable or the date on which payment thereof was duly provided for, whichever occurred later;

•    

•    that are imposed or withheld pursuant to Sections 1471 through 1474 of the U.S. Internal Revenue Code of 1986, as amended (the "Code"), as of the issue date (or any amended or successor version of such sections), any regulations promulgated thereunder, any official interpretations thereof, any similar law or regulation adopted pursuant to an intergovernmental agreement between a non-U.S. jurisdiction and the United States with respect to the foregoing or any agreements entered into pursuant to Section 1471(b)(1) of the Code;

•    that would not have been imposed if presentation for payment of the relevant debt security or guarantee had been made to a paying agent other than the paying agent to which the presentation was made; or

•    any combination of the foregoing items;

nor shall additional amounts be paid with respect to any payment of the principal of or premium, if any, or interest, if any, on any debt security or any payment in respect of any guarantee to any such holder or beneficial owner who is a fiduciary or a partnership or a beneficial owner who is other than the sole beneficial owner of such payment to the extent a beneficiary or settlor with respect to such fiduciary or a member of such partnership or a beneficial owner would not have been entitled to such additional amounts had it been the holder of the debt security.

All references herein, other than under "-Defeasance" below, to the payment of the principal of or premium, if any, or interest, if any, on or the net proceeds received on the sale or exchange of, any debt securities or any payment in respect of any guarantee shall be deemed to include additional amounts to the extent that, in that context, additional amounts are, were or would be payable.

Aon Ireland’s Aon UK's, AGH’s and Aon Delaware's obligations to pay additional amounts if and when due will survive the termination of the indentures and the payment of all other amounts in respect of the debt securities.

If, as a result of Aon Ireland, Aon UK's, AGH’s or Aon Delaware's consolidation, merger with or conversion into a successor person organized under the laws of a jurisdiction other than Ireland, the United Kingdom or the United States (or, in each case, any political subdivision or taxing authority thereof) as described under "-Consolidation and Merger" above, or the conveyance, transfer or lease by Aon Ireland, Aon UK, AGH, or Aon Delaware of its assets substantially as an entirety to such successor person, and such an entity expressly assumes the obligations of Aon Ireland, Aon UK, AGH or Aon Delaware under the indentures and any outstanding debt securities or guarantees, as applicable, such successor person will pay additional amounts on the same basis as described above, except that references to a "Home Country Jurisdiction" will be treated as references to the Ireland, United Kingdom, the United States and the country in which such successor person is organized or resident (or deemed resident for tax purposes).

Optional Tax Redemption

The issuer may redeem any series of debt securities in whole, but not in part, at its option at any time prior to maturity, upon the giving of not less than 10 nor more than 90 days' notice of tax redemption to the holders, at a redemption price equal to the principal amount plus accrued and unpaid interest, if any, to the redemption date (except in the case of discounted debt securities, which may be redeemed at the redemption price specified by the terms of each series of such debt securities), if:

•    the issuer determines that, as a result of any change in, amendment to or announced proposed change in the laws or any regulations or rulings promulgated thereunder of a Home Country Jurisdiction (or of any political subdivision or taxing authority thereof) or, in the event of the assumption of the issuer's or the guarantor's obligations under the debt securities or guarantee, as applicable, by a successor person not organized under the laws of a Home Country Jurisdiction (or, in each case, any political subdivision or taxing authority thereof as described under "-Consolidation and Merger" above), the jurisdiction in which such successor person is organized (or deemed resident for tax purposes), or any change in the application or official interpretation of such laws, regulations or rulings, or (in either case) any change in the application or official interpretation of, or any execution of or amendment to, any treaty or treaties affecting taxation to which any such jurisdiction is a party, which change, execution or amendment becomes effective on or after (i) the issue date of the applicable debt securities or guarantee, (ii) in the event of the assumption by a successor person of the issuer's or the guarantor's obligations under the applicable indenture and the debt securities or guarantee, as applicable, as described under "-Consolidation and Merger" above, under the laws of a jurisdiction other than a Home Country Jurisdiction (or, in each case, any political subdivision or taxing authority thereof), with respect to taxes imposed by such other jurisdiction, the date of the transaction resulting in such assumption or (iii) such other date specified with respect to the debt securities or guarantee, as applicable, and, in the case of each of (i), (ii) or (iii), the issuer, the guarantor or such successor person, as applicable, would be required to pay additional amounts (as described under "-Payment of Additional Amounts" above) with respect to that series of debt securities or under a guarantee, as the case may be, on the next succeeding interest payment date for the relevant debt securities and the payment of such additional amounts cannot be avoided by the use of reasonable measures available to the issuer, the guarantor or such successor person, as applicable; or

•    the issuer determines, based upon an opinion of independent counsel of recognized standing that, as a result of any action taken by any legislative body of, taxing authority of, or any action brought in a court of competent jurisdiction in, a Home Country Jurisdiction (or any political subdivision or taxing authority thereof) or, in the event of the assumption of the issuer's or the guarantor's obligations under the debt securities or guarantee, as applicable, by a successor person not organized under the laws of a Home Country Jurisdiction (or, in each case, any political subdivision thereof as described under "-Consolidation and Merger" above), the jurisdiction in which such successor person is organized (or deemed resident for tax purposes), which action is taken or brought on or after (i) the issue date of the applicable debt securities or guarantee, (ii) in the event of the assumption by a successor person of the issuer's or the guarantor's obligations under the applicable indenture and the debt securities or guarantee, as applicable, as described under "-Consolidation and Merger" above, under the laws of a jurisdiction other than a Home Country Jurisdiction (or, in each case, any political subdivision or taxing authority thereof), with respect to taxes imposed by such other jurisdiction, the date of the transaction resulting in such assumption or (iii) such other date specified with respect to the debt securities and, in the case of each of (i), (ii) and (iii), there is a substantial probability that the circumstances described above would exist.

No notice of any such redemption may be given earlier than 90 days prior to the earliest date on which Aon Ireland, Aon UK, AGH, Aon Delaware or such successor person, as applicable, would be obligated to pay any additional amounts.

Aon Ireland, Aon UK, AGH, Aon Delaware or such successor person will also pay to each holder, or make available for payment to each such holder, on the redemption date, any additional amounts (as described under "-Payment of Additional Amounts" above) resulting from the payment of such redemption price by it. Prior to the delivery of any notice of redemption, Aon Ireland, Aon UK, AGH, Aon Delaware or such successor person will deliver to the trustee an officer's certificate stating that it is entitled to effect or cause a redemption and setting forth a statement of facts showing that the conditions precedent of the right so to redeem or cause such redemption have occurred, and in the case of a redemption based on an opinion of independent counsel referred to in the second bullet above, such independent counsel's opinion. Delivery of any notice of redemption will be conclusive and binding on the holders of the securities being redeemed.

Any notice of redemption will be irrevocable once an officer's certificate has been delivered to the trustee.

Defeasance

Defeasance and Discharge. Unless the debt securities of any series provide otherwise, the issuer and, if applicable, the guarantor may be discharged from any and all obligations in respect of the debt securities of that series and any related guarantee, as applicable (except for certain obligations to register the transfer or exchange of debt securities of that series, to replace stolen, destroyed, lost or mutilated debt securities of that series, to maintain paying agencies, to execute and furnish definitive securities evidenced by temporary securities, to return moneys deposited with or paid to the trustee or any paying agent remaining unclaimed for three years, to compensate and indemnify the applicable trustee or to furnish such trustee (if that trustee is not the registrar) with the names and addresses of holders of debt securities of that series). This discharge, referred to as defeasance, will occur only if, among other things:

•    the issuer or, if applicable, the guarantor or both irrevocably deposit with the applicable trustee, in trust, money and/or securities of the government which issues the currency in which the debt securities of that series are payable or securities of agencies backed by the full faith and credit of that government, which, through the payment of interest and principal in accordance with their terms, will provide, in the opinion of a nationally recognized public accounting firm, enough money to pay each installment of principal of, and any premium and interest on, and any additional amounts known to be payable at the time of such defeasance and discharge and any mandatory sinking fund payments in respect of, the debt securities of that series on the applicable due dates for those payments in accordance with the terms of those debt securities; and

•    the issuer or, if applicable, the guarantor delivers to the applicable trustee an opinion of counsel confirming that the holders of the debt securities of that series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of such defeasance and will be subject to U.S. federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the discharge had not occurred.

That opinion must state that the issuer or, if applicable, the guarantor has received from the U.S. Internal Revenue Service a ruling or, since the date of execution of the applicable indenture, there has been a change in the applicable United States federal income tax law, in any case, in support of that opinion.

In addition, the issuer or, if applicable, the guarantor or both may also obtain a discharge of either indenture with respect to all debt securities issued under that indenture and any related guarantee, as applicable, by depositing with the applicable trustee, in trust, enough money to pay all amounts due on the debt securities on the date those payments are due or upon redemption of all of those debt securities, so long as those debt securities are by their terms to become due and payable within one year or are to be called for redemption within one year.

Defeasance of Certain Covenants and Certain Events of Default. Unless the debt securities of any series provide otherwise, upon compliance with certain conditions:

•    the issuer and, if applicable, the guarantor may omit to comply with any provision of the applicable indenture (except for certain obligations to register the transfer or exchange of debt securities of that series, to replace stolen, destroyed, lost or mutilated debt securities of that series, to maintain paying agencies, to execute and furnish definitive securities evidenced by temporary securities, to return moneys deposited with or paid to the trustee or any paying agent on any debt security and not applied to payments on the debt securities but remaining unclaimed for three years, to punctually pay the principal of and premium or interest, if any, on the debt securities, to deliver to the trustee an annual statement as to default, to adhere to the covenants with respect to payment on the debt securities on default, to adhere to the resignation or removal procedures regarding the trustee, to compensate and indemnify the applicable trustee or to furnish that trustee (if that trustee is not the registrar) with the names and addresses of holders of debt securities of that series), including the covenant described under "-Consolidation and Merger"; and

•    any omission to comply with those covenants will not constitute an event of default with respect to the debt securities of that series ("covenant defeasance").

The conditions include, among other things:

•    irrevocably depositing with the applicable trustee, in trust, money and/or securities of the government which issues the currency in which the debt securities of that series are payable or securities of agencies backed by the full faith and credit of that government, which, through the payment of interest and principal in accordance with their terms, will provide, in the opinion of a nationally recognized public accounting firm, enough money to pay each installment of principal of, any premium and interest on, and any additional amounts known to be payable at the time of such covenant defeasance and any mandatory sinking fund payments in respect of, the debt securities of that series on the applicable due dates for those payments in accordance with the terms of those debt securities; and

•    delivering to the applicable trustee an opinion of counsel to the effect that the holders of the debt securities of that series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of the covenant defeasance and will be subject to U.S. federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the covenant defeasance had not occurred.

Covenant Defeasance and Certain Other Events of Default. If the issuer or, if applicable, the guarantor exercises or both exercise the option to effect a covenant defeasance with respect to the debt securities of any series as described above and the debt securities of that series are thereafter declared due and payable because of an event of default (other than an event of default caused by failing to comply with the covenants that are defeased), the amount of money and securities it has or they have deposited with the applicable trustee would be sufficient to pay amounts due on the debt securities of that series on their respective due dates but may not be sufficient to pay amounts due on the debt securities of that series at the time of acceleration resulting from that event of default. However, the issuer and, if applicable, the guarantor would remain liable for any shortfall.

Modification and Waiver

Each indenture provides that the issuer and, if applicable, the guarantor may enter into supplemental indentures with the applicable trustee without the consent of the holders of debt securities to:

•    document the fact that a successor entity has assumed the issuer's or, if applicable, the guarantor's obligations;

•    add covenants or events of default or to surrender any right or power conferred upon the issuer or, if applicable, the guarantor for the benefit of the holders of debt securities;

•    add or change such provisions as are necessary to permit the issuance of global debt securities;

•    cure any ambiguity or correct any inconsistency in the indenture or in the terms of the debt securities as shall not adversely affect the interests of the holders of debt securities in any material respect;

•    conform the applicable indenture or the terms of the debt securities or guarantees to any terms set forth in this prospectus or an applicable prospectus supplement;

•    document the fact that a successor trustee has been appointed; or

•    establish the forms and terms of debt securities of any series.

The issuer and, if applicable, the guarantor may enter into a supplemental indenture to modify an indenture with the consent of the applicable trustee and the holders of at least a majority in principal amount of outstanding debt securities of each series affected by such supplemental indenture. However, the issuer and, if applicable, the guarantor may not modify an indenture without the consent of the holders of all then-outstanding debt securities of the affected series issued under that indenture to:

•    extend the maturity date of, or change the due date of any installment of principal of or interest on, or payment of additional amounts with respect to, the debt securities of that series;

•    reduce the principal amount of, or any premium payable or interest rate on, the debt securities of that series;

•    reduce the amount due and payable upon acceleration or make payments thereon payable in any currency other than that provided in that debt security;

•    make any change that adversely affects the right, if any, to convert or exchange any debt security for shares or other securities or property in accordance with its terms;

•    impair the right to institute suit for the enforcement of any such payment on or after its due date; or

•    reduce the percentage in principal amount of outstanding debt securities of any series, the consent of whose holders is necessary to effect any such modification or amendment of the indenture, for waiver of compliance with certain covenants and provisions in the indenture or for waiver of certain defaults.

The holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive any past default under the applicable indenture with respect to that series, except a default in the payment of the principal of or any premium or any interest on, any debt security of that series or in respect of a provision which under the applicable indenture cannot be modified or amended without the consent of the holder of each outstanding debt security of that affected series.

Global Securities

The debt securities of a series may be issued in whole or in part in the form of one or more global certificates that the issuer will deposit with a depositary identified in an applicable prospectus supplement. Unless and until it is exchanged in whole or in part for the individual debt securities that it represents, a global security may not be transferred except as a whole:

•    by the applicable depositary to a nominee of the depositary;

•    by any nominee to the depositary itself or another nominee; or

•    by the depositary or any nominee to a successor depositary or any nominee of the successor.

An applicable prospectus supplement will describe the specific terms of the depositary arrangement with respect to a series of debt securities. The following provisions are anticipated to generally apply to depositary arrangements.

When a global security is issued, the depositary for the global security or its nominee will credit, on its book-entry registration and transfer system, the respective principal amounts of the individual debt securities represented by that global security to the accounts of persons that have accounts with the depositary ("participants"). Those accounts will be designated by the dealers, underwriters or agents with respect to the underlying debt securities or by the issuer if those debt securities are offered and sold directly by the issuer. Ownership of beneficial interests in a global security will be limited to participants or persons that may hold interests through participants. For interests of participants, ownership of beneficial interests in the global security will be shown on records maintained by the applicable depositary or its nominee. For interests of persons other than participants, that ownership information will be shown on the records of participants. Transfer of that ownership will be effected only through those records. The laws of some states require that certain purchasers of securities take physical delivery of securities in definitive form. These limits and laws may impair Aon Ireland’s, Aon UK's, Aon Delaware’s or AGH’s ability to transfer beneficial interests in a global security.

As long as the depositary for a global security, or its nominee, is the registered owner of that global security, the depositary or nominee will be considered the sole owner or holder of the debt securities represented by the global security for all purposes under the applicable indenture. Except as provided below, owners of beneficial interests in a global security:

•    will not be entitled to have any of the underlying debt securities registered in their names;

•    will not receive or be entitled to receive physical delivery of any of the underlying debt securities in definitive form; and

•    will not be considered the owners or holders under the indenture relating to those debt securities.

Payments of the principal of, any premium on and any interest on individual debt securities represented by a global security registered in the name of a depositary or its nominee will be made to the depositary or its nominee as the registered owner of the global security representing such debt securities. No issuer, guarantor, trustee, paying agent or registrar for the debt securities will be responsible for any aspect of the records relating to or payments made by the depositary or any participants on account of beneficial interests in the global security.

It is expected that the depositary or its nominee, upon receipt of any payment of principal, any premium or interest relating to a global security representing any series of debt securities, immediately will credit participants' accounts with the payments. Those payments will be credited in amounts proportional to the respective beneficial interests of the participants in the principal amount of the global security as shown on the records of the depositary or its nominee. It is also expected that payments by participants to owners of beneficial interests in the global security held through those participants will be governed by standing instructions and customary practices. This is now the case with securities held for the accounts of customers registered in "street name." Those payments will be the sole responsibility of those participants.

If the depositary for a series of debt securities is at any time unwilling, unable or ineligible to continue as depositary and a successor depositary is not appointed within 90 days, the issuer will issue individual debt securities of that series in exchange for the global security or securities representing that series. In addition, the issuer may at any time in its sole discretion determine not to have any debt securities of a series represented by one or more global securities. In that event, the issuer will issue individual debt securities of that series in exchange for the global security or securities. Furthermore, if specified in an applicable prospectus supplement, an owner of a beneficial interest in a global security may, on terms acceptable to the issuer, the trustee and the applicable depositary, receive individual debt securities of that series in exchange for those beneficial interests. The foregoing is subject to any limitations described in an applicable prospectus supplement. In any such instance, the owner of the beneficial interest will be entitled to physical delivery of individual debt securities equal in principal amount to the beneficial interest and to have the debt securities registered in its name. Those individual debt securities will be issued in any authorized denominations.

Subordination under the Aon Ireland Subordinated Debt Indenture

The Aon Ireland subordinated debt securities and the Aon Ireland subordinated debt guarantees will be subordinate and junior in right of payment to all senior indebtedness of Aon Ireland and Aon Delaware, respectively, to the extent provided in the Aon Ireland subordinated debt indenture. Neither Aon Ireland, as issuer, nor Aon Delaware, Aon UK or AGH, as an Aon Ireland subordinated debt guarantor, may make any payments on account of principal or any premium, redemption, interest or any other amount payable under the Aon Ireland subordinated debt securities or the Aon Ireland subordinated debt guarantees, as the case may be, at any time when it has defaulted with respect to payment of principal or any premium, interest, sinking fund or other payment due on its senior indebtedness. If either Aon Ireland, as issuer, or Aon Delaware, Aon UK or AGH, as an Aon Ireland subordinated debt guarantor, makes any payment described in the foregoing sentence before all of its senior indebtedness is paid in full, such payment or distribution will be applied to pay off the applicable senior indebtedness which remains unpaid. Subject to the condition that the senior indebtedness of Aon Ireland or Aon Delaware, as the case may be, is paid in full, if any such payments are made on the senior indebtedness of Aon Ireland or Aon Delaware, as the case may be, as described above, the holders of Aon Ireland subordinated debt securities or Aon Ireland subordinated debt guarantees will be subrogated to the rights of the senior debt security holders of Aon Ireland or Aon Delaware, as the case may be.

The Aon Ireland subordinated debt indenture defines the term "senior indebtedness" to mean:

•    all indebtedness of Aon Ireland or Aon Delaware, as the case may be, whether outstanding on the date of the Aon Ireland subordinated debt indenture or incurred later, for money borrowed (other than Aon Ireland subordinated debt securities or Aon Delaware subordinated debt securities, as the case may be) or otherwise evidenced by a note or similar instrument given in connection with the acquisition of any property or assets (other than inventory or other similar property acquired in the ordinary course of business), including securities or for the payment of money relating to a capitalized lease obligation (as defined in the Aon Ireland subordinated debt indenture);

•    any indebtedness of others described in the preceding bullet point which Aon Ireland or Aon Delaware, as the case may be, has guaranteed or which is otherwise its legal obligation;

•    any of Aon Ireland's or Aon Delaware's, as the case may be, indebtedness under interest rate swaps, caps or similar hedging agreements and foreign exchange contracts, currency swaps or similar agreements; and

•    renewals, extensions, refundings, restructurings, amendments and modifications of any indebtedness or guarantee

described above.

"Senior indebtedness" does not include:

•    any indebtedness of Aon Ireland or Aon Delaware, as the case may be, to its subsidiaries; or

•    any indebtedness of Aon Ireland or Aon Delaware, as the case may be, which by its terms ranks equal or subordinated to the Aon Ireland subordinated debt securities or Aon Ireland subordinated debt guarantees in rights of payment or upon liquidation.

Because of the subordination provisions described above, some of the general creditors of Aon Ireland, Aon UK, AGH, or Aon Delaware, as the case may be, may recover proportionately more than holders of the Aon Ireland subordinated debt securities or Aon Ireland subordinated debt guarantees if the assets of Aon Ireland, Aon UK, AGH, or Aon Delaware, as the case may be, are distributed as a result of insolvency or bankruptcy. The Aon Ireland subordinated debt indenture provides that the subordination provisions will not apply to cash, properties and securities held in trust pursuant to the satisfaction and discharge and the legal defeasance provisions of the Aon Ireland subordinated debt indenture. See "-Defeasance" for additional information regarding the legal defeasance provisions affecting the subordinated debt.

The approximate amount of senior indebtedness outstanding for each of Aon Ireland, Aon UK, AGH, and Aon Delaware as of a recent date will be set forth (or incorporated by reference) in any prospectus supplement under which Aon Ireland offers to sell Aon Ireland subordinated debt securities.

Subordination under the Aon Delaware Subordinated Debt Indenture

The Aon Delaware subordinated debt securities and the Aon Delaware subordinated debt guarantees will be subordinate and junior in right of payment to all senior indebtedness of Aon Delaware, AGH, Aon Ireland and Aon UK, respectively, to the extent provided in the Aon Delaware subordinated debt indenture. Neither Aon Delaware, as issuer, nor Aon UK, Aon Ireland or AGH, as an Aon Delaware subordinated debt guarantor, may make any payments on account of principal or any premium, redemption, interest or any other amount payable under the Aon Delaware subordinated debt securities or the Aon Delaware subordinated debt guarantees, as the case may be, at any time when it has defaulted with respect to payment of principal or any premium, interest, sinking fund or other payment due on its senior indebtedness. If either Aon Delaware, as issuer, or Aon UK, Aon Ireland or AGH, as an Aon Delaware subordinated debt guarantor, makes any payment described in the foregoing sentence before all of its senior indebtedness is paid in full, such payment or distribution will be applied to pay off the applicable senior indebtedness which remains unpaid. Subject to the condition that the senior indebtedness of Aon Delaware, Aon Ireland, AGH, or Aon UK, as the case may be, is paid in full, if any such payments are made on the senior indebtedness of Aon Delaware, Aon Ireland, AGH, or Aon UK, as the case may be, as described above, the holders of Aon Delaware subordinated debt securities or Aon Delaware subordinated debt guarantees will be subrogated to the rights of the senior debt security holders of Aon Delaware, Aon Ireland, AGH, or Aon UK, as the case may be.

The Aon Delaware subordinated debt indenture defines the term "senior indebtedness" to mean:

•    all indebtedness of Aon Delaware or Aon Ireland, as the case may be, whether outstanding on the date of the Aon Delaware subordinated debt indenture or incurred later, for money borrowed (other than Aon Delaware subordinated debt securities or Aon Ireland subordinated debt securities, as the case may be) or otherwise evidenced by a note or similar instrument given in connection with the acquisition of any property or assets (other than inventory or other similar property acquired in the ordinary course of business), including securities or for the payment of money relating to a capitalized lease obligation (as defined in the Aon Delaware subordinated debt indenture);

•    any indebtedness of others described in the preceding bullet point which Aon Delaware or Aon Ireland, as the case may be, has guaranteed or which is otherwise its legal obligation;

•    any of Aon Delaware's or Aon Ireland's, as the case may be, indebtedness under interest rate swaps, caps or similar hedging agreements and foreign exchange contracts, currency swaps or similar agreements; and

•    renewals, extensions, refundings, restructurings, amendments and modifications of any indebtedness or guarantee

described above.

"Senior indebtedness" does not include:

•    any indebtedness of Aon Delaware or Aon Ireland, as the case may be, to its subsidiaries; or

•    any indebtedness of Aon Delaware or Aon Ireland, as the case may be, which by its terms ranks equal or subordinated to the Aon Delaware subordinated debt securities or Aon Delaware subordinated debt guarantees in rights of payment or upon liquidation.

Because of the subordination provisions described above, some of the general creditors of Aon Delaware, AGH, or Aon Ireland, as the case may be, may recover proportionately more than holders of the Aon Delaware subordinated debt securities or Aon Delaware subordinated debt guarantees if the assets of Aon Ireland, AGH, or Aon Delaware, as the case may be, are distributed as a result of insolvency or bankruptcy. The Aon Delaware subordinated debt indenture provides that the subordination provisions will not apply to cash, properties and securities held in trust pursuant to the satisfaction and discharge and the legal defeasance provisions of the Aon Delaware subordinated debt indenture. See "-Defeasance" for additional information regarding the legal defeasance provisions affecting the subordinated debt.

Aon Delaware will set forth (or incorporate by reference) the approximate amount of senior indebtedness outstanding for each of Aon Delaware, AGH, and Aon Ireland as of a recent date in any prospectus supplement under which Aon Delaware offers to sell Aon Delaware subordinated debt securities.

Guarantees

Under each guarantee, the applicable guarantor will unconditionally guarantee the due and punctual payment of the principal, interest (if any), premium (if any) and all other amounts due on the applicable debt securities and under the indenture when the same shall become due and payable, whether at maturity, pursuant to mandatory or optional redemption or repayments, by acceleration or otherwise, in each case after any applicable grace periods or notice requirements, according to the terms of the applicable debt securities.

The obligations of each guarantor under the guarantees will be full and unconditional, joint and several, regardless of the enforceability of the applicable debt securities, and will not be discharged until all obligations under those debt securities and the applicable indenture are satisfied. Holders of the applicable debt securities may proceed directly against the guarantor under the applicable guarantee if an event of default affecting those debt securities occurs without first proceeding against the issuer.

Conversion Rights

An applicable prospectus supplement will describe the terms and conditions, if any, on which debt securities being offered are convertible into any other securities. Such terms will include the conversion price, the conversion period, provisions as to whether conversion will be at the issuer's option or the option of the holder, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of those debt securities.

Regarding the Trustee

The issuers have commercial deposits and custodial arrangements with The Bank of New York Mellon Trust Company, N.A. ("BNYM") and may have borrowed money from BNYM in the normal course of business. The issuers may enter into similar or other banking relationships with BNYM in the future in the normal course of business. In addition, the issuers have provided brokerage and other insurance services in the ordinary course of their respective businesses for BNYM. BNYM may also act as trustee with respect to other debt securities one or both of the issuers have issued.

BNYM will be serving as the trustee under the senior indentures and the subordinated indentures. Consequently, if an actual or potential event of default occurs with respect to either the senior debt securities or the subordinated debt securities, BNYM may be considered to have a conflicting interest for purposes of the Trust Indenture Act. In that case, BNYM may be required to resign under one or more indentures, and the applicable issuer and, if applicable, the applicable guarantor would be required to appoint a successor trustee. For this purpose, a "potential" event of default means an event that would be an event of default if the requirements for giving Aon Ireland, Aon UK, AGH or Aon Delaware default notice or for the default having to exist for a specific period of time were disregarded.

Governing Law

The debt securities, the guarantees and the indentures will be governed by and construed in accordance with the laws of the State of New York, except that, as the indentures specify, the subordination provisions of each series of Aon Ireland subordinated debt securities, any Aon Delaware subordinated debt guarantee and the Aon Ireland subordinated indenture, as they apply to Aon Ireland, will be governed by and construed in accordance with the laws of Ireland (other than the appointment of any attorney-in-fact, which shall be governed by the laws of the State of New York).

EX-10.6

EXECUTION VERSION

AMENDMENT TO THE

AON DEFERRED COMPENSATION PLAN

This Sixth 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 13, 2022, 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 June 30, 2022, by adding the following new Section 2 to Supplement B of the Plan:

“2. Partial Plan Termination – eDiscovery Business. The Plan shall be terminated and liquidated, effective June 30, 2022, 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 Aon Cyber Solutions’s eDiscovery business. 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, 2023, to be distributed no later than March 15, 2023.”

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.

IN WITNESS WHEREOF, the Company has caused this Amendment to the Plan to be executed on its behalf by its duly authorized officers, this 16th day of December 2022.

AON CORPORATION

By: Lisa Stevens

Lisa Stevens

Chief People Officer

EX-10.7

EXECUTION VERSION

SEVENTH AMENDMENTTO THE

AON SUPPLEMENTAL SAVINGS PLAN

(As amended and restated effective January 1, 2017)

This Seventh 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 Committee dated June 13, 2016, the OCC agreed to assume from the Board the duties and responsibilities of the Company as the sponsor of the Plan; and

WHEREAS, pursuant to the resolutions of the Committee dated September 13, 2022, 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 June 30, 2022, by adding the following new item 3 to Supplement B of the Plan:

“3.    Partial Plan Termination – eDiscovery Business. The Plan shall be terminated and liquidated, effective June 30, 2022, 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 Aon Cyber Solutions’s eDiscovery business. 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, 2023, to be distributed no later than March 15, 2023.”

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.

IN WITNESS WHEREOF, the Company has caused this Amendment to the Plan to be executed on its behalf by its duly authorized officers, this 16th day of December 2022.

AON CORPORATION

By: Lisa Stevens

Lisa Stevens

Chief People Officer

EX-21.1

Aon plc - Worldwide Subsidiaries as of December 31, 2022		Exhibit 21
Name	Country	State/Province
Admiseg S.A.	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
Aon Advisory Australia Pty Limited	Australia
Hogg Robinson Financial Services Limited	Australia
Affinity Risk Partners (Brokers) 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 Reinsurance Australia Limited	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	Australia
Aon Holdings Australia Pty Ltd	Australia
Aon Product Design & Development Australia Pty Ltd	Australia
Aon Risk & Asset Management Pty Ltd	Australia
Aon Risk Services Australia Limited	Australia
Aon Services Pty Ltd	Australia

Name	Country	State/Province
Aon Superannuation Pty Ltd	Australia
Cut-e Australia Pty Ltd	Australia
HIA Insurance Services Pty Ltd	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
Marilla Reinsurance Ltd.	Bermuda
Marilla Capital Ltd.	Bermuda
Aon Finance Bermuda 1 Ltd.	Bermuda
Marilla Investment Management Ltd.	Bermuda
Marilla Reinsurance Holdings Ltd.	Bermuda
Aon (Bermuda) Ltd.	Bermuda
Aon Bermuda Holding Company Limited	Bermuda
Aon Bermuda QI Holdings Ltd.	Bermuda
Aon Group (Bermuda) Ltd.	Bermuda
Aon Insurance Managers (Bermuda) Ltd.	Bermuda
One Underwriting (Bermuda) Ltd.	Bermuda
International Risk Management Group Ltd.	Bermuda
White Rock Insurance (Americas) Ltd.	Bermuda
White Rock Insurance (SAC) Ltd.	Bermuda

Name	Country	State/Province
White Rock Services (Bermuda) Ltd.	Bermuda
Aon Bolivia S.A. Corredores de Seguros	Bolivia
Aon Consulting Bolivia S.R.L.	Bolivia
Aon Re Bolivia S.A. Corredores de Reaseguros	Bolivia
ADM Administradora de Benefícios Ltda.	Brazil
Aon Affinity do Brasil Servicos e Corretora de Seguros Ltda.	Brazil
Associação Instituto Aon	Brazil
Aon Brasil Corretora de Resseguros Ltda.	Brazil
Aon Holdings Corretores de Seguros Ltda.	Brazil
Blist – Soluções, Assistência e Serviços Empresariais Ltda.	Brazil
Aon Solutions Canada Inc.	Canada	Nova Scotia
Groupe-conseil Aon Inc.	Canada	Quebec
Aon Solutions Canada, a Partnership	Canada	Ontario
Aon Solutions Corp.	Canada	Nova Scotia
7193599 Canada Inc.	Canada	Ontario
Aon Reinsurance Canada ULC	Canada	Nova Scotia
Aon Canada Holdings N.S. ULC	Canada	Nova Scotia
Aon Canada Inc.	Canada	Ontario
Aon Direct Group Inc.	Canada	Ontario
Aon Finance Canada 1 Corp.	Canada	Ontario
Aon Finance Canada 2 Corp.	Canada	Ontario
Aon Finance N.S. 1, ULC	Canada	Nova Scotia
Aon Finance N.S. 5, ULC	Canada	Nova Scotia
Aon Investments Canada Inc.	Canada	Ontario
Aon Parizeau Inc.	Canada	Quebec
Aon Reed Stenhouse Inc.	Canada	Ontario
Aon Securities Investment Management Inc.	Canada	Ontario
Coles Aon Partnership	Canada	British Columbia
Aon Solutions 3 Limited	Canada	British Columbia

Name	Country	State/Province
IAO Actuarial Consulting Services Inc.	Canada	Ontario
J. Allan Brown Consultants, Inc.	Canada	British Columbia
K & K Insurance Brokers, Inc. Canada	Canada	Ontario
Linx Underwriting Solutions Inc.	Canada	Ontario
Minet Inc.	Canada	Quebec
Townsend (Global Real Estate) GP Ontario Inc.	Canada	Ontario
USLP Underwriting Solutions LP	Canada	Alberta
Stroz Friedberg Canada Inc.	Canada	Ontario
Aon Finance N.S. 9, ULC	Canada	Nova Scotia
Aon Insurance Managers (Cayman) Ltd.	Cayman Islands
Aon Risk Solutions (Cayman) Ltd.	Cayman Islands
Aon Chile Corredores de Reaseguros Limitada	Chile
Aon Risk Services (Chile) Corredores de Seguros Limitada	Chile
Aon Risk Services Holdings (Chile) Ltda.	Chile
Inversiones Benfield Chile Ltda.	Chile
Aon Enterprise Solutions (Shanghai) Co., Ltd.	China
Aon-COFCO Insurance Brokers Co., Ltd.	China
Aon Corporation (Beijing Representative Office)	China
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

Name	Country	State/Province
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, Suomen sivuliike	Finland
Aon Assessment (Finland) Oy	Finland
Aon Finland Oy	Finland
Aon Services S.à r.l.	France
Aon France	France
Aon Holdings France SNC	France
TRIUM GmbH Insurance Broker	Germany
Karl Köllner GmbH Versicherungsmakler	Germany
Karl Köllner GmbH Marine Insurance Brokers	Germany
Aon Beteiligungsmanagement Deutschland GmbH & Co. KG	Germany
Aon Versicherungsmakler Deutschland GmbH	Germany
Aon Deutschland Beteiligungs GmbH	Germany
Aon Solutions Germany GmbH	Germany
Aon Trust Germany GmbH	Germany
Aon Holding Deutschland GmbH	Germany
Aon Pensions Insurance Broker GmbH	Germany
Aon Risiko- und Unternehmensberatungs GmbH	Germany
Aon Versicherungsberatungs GmbH	Germany
Aon Assessment GmbH	Germany
Hamburger Gesellschaft zur Forderung des Versicherungswesens mbH	Germany
One Underwriting Agency GmbH	Germany
PRORÜCK Rückversicherungs-Aktiengesellschaft	Germany
UNIT Versicherungsmakler GmbH	Germany
UnitedPensions Deutschland AG	Germany
Wannet Sports Insurance GmbH	Germany

Name	Country	State/Province
Aon Insurance Managers Gibraltar Limited	Gibraltar
White Rock Insurance (Gibraltar) PCC Limited	Gibraltar
Aon Greece S.A.	Greece
Aon Solutions Greece S.A.	Greece
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
Aon Reinsurance China Limited	Hong Kong
Aon Solutions 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 Securities (Hong Kong) Limited	Hong Kong
Aon Services Hong Kong Limited	Hong Kong
Essar Insurance Services Limited	Hong Kong
Townsend Group Asia Limited	Hong Kong
Aon Hungary Insurance Brokers Risk and Human Consulting LLC	Hungary
Aon India Insurance Brokers Private Limited	India
Aon Consulting Private Limited	India
PT Aon Reinsurance Brokers Indonesia	Indonesia

Name	Country	State/Province
PT Aon Indonesia	Indonesia
Aon Bahrain W.L.L. (Iraq Branch)	Iraq
Aon Solutions UK Limited (IRL Investment Branch)	Ireland
Aon Assessment (Ireland) Limited	Ireland
Aon Broking Technology Limited	Ireland
Aon Commercial Services and Operations Ireland Limited	Ireland
Aon Commercial Services Ireland Limited	Ireland
Aon Solutions Ireland Limited	Ireland
Aon Insurance Managers (Dublin) Limited	Ireland
Aon Insurance Managers (Shannon) Limited	Ireland
Aon Investment Holdings Ireland Limited	Ireland
Aon Treasury Ireland Limited	Ireland
Bacon & Woodrow Partnerships (Ireland) Limited	Ireland
Becketts (Trustees) Limited	Ireland
Cut-e Assessment Global Holdings Limited	Ireland
Aon Assessment Solutions Europe Limited	Ireland
Aon Ireland Limited	Ireland
Private Clients Trustees Limited	Ireland
Randolph Finance Unlimited Company	Ireland
The Aon Ireland MasterTrustee DAC	Ireland
Aon Reem Company Limited	Ireland
Aon plc	Ireland
Driftbrook Unlimited Company	Ireland
Aon Reinsurance Israel Ltd.	Israel
Aon Holdings Israel Ltd.	Israel
Aon Israel Insurance Brokerage Ltd.	Israel
Delek Motors Insurance Agency (2003) Ltd.	Israel
I. Beck Insurance Agency (1994) Ltd.	Israel
National Insurance Office Ltd.	Israel

Name	Country	State/Province
Ronnie Elementary Insurance Agency Ltd.	Israel
Aon Reinsurance Italia S.p.A.	Italy
Aon Advisory and Solutions S.r.l.	Italy
Aon Italia S.r.l.	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
Aon Assessment Solutions Europe Limited (Italy Branch)	Italy
Aon Group Japan Limited	Japan
Aon Solutions Japan Ltd.	Japan
Aon Holdings Japan Ltd.	Japan
Aon Japan Ltd.	Japan
PayPay Insurance Service Corporation	Japan
Aon Consulting Kazakhstan LLP	Kazakhstan
Insurance Broker Aon Kazakhstan LLP	Kazakhstan
Aon Hewitt Consulting Korea Inc.	Korea, Republic Of (South)
Aon Korea Inc.	Korea, Republic Of (South)
UADBB Aon Baltic (Latvia Branch)	Latvia
Aon Insurance Managers (Liechtenstein) AG	Liechtenstein
One Underwriting UAB	Lithuania
UADBB Aon Baltic	Lithuania
Aon Holdings Luxembourg S.a.r.l.	Luxembourg
Aon Neudorf Finance S.a.r.l.	Luxembourg
Aon Re Canada Holdings S.a.r.l.	Luxembourg
Aon Global Operations Luxembourg S.a.r.l.	Luxembourg
Aon Randolph Luxembourg S.a.r.l.	Luxembourg
TG Voltesso GP S.a.r.l.	Luxembourg
Aon Insurance Managers (Luxembourg) S.A.	Luxembourg

Name	Country	State/Province
Aon Global Operations SE	Luxembourg
Aon Global Risk Consulting Luxembourg S.à r.l.	Luxembourg
Aon Belgium B.V. (Luxembourg Branch)	Luxembourg
Aon Hong Kong Limited (Macau Branch)	Macau
Aon Reinsurance Malaysia Limited	Malaysia
Aon Malaysia Sdn. Bhd.	Malaysia
Aon Insurance Brokers (Malaysia) Sdn. Bhd.	Malaysia
Aon Malta Affinity Services Limited	Malta
Aon Insurance Managers (Malta) PCC Limited	Malta
Aon Services (Malta) Limited	Malta
White Rock Insurance (Europe) PCC Limited	Malta
White Rock Insurance (Netherlands) PCC Limited	Malta
Aon (Isle of Man) Limited	Man, Isle of
Aon Corporate Services (Isle of Man) Limited	Man, Isle of
Aon Holdings (Isle of Man) Limited	Man, Isle of
Aon Insurance Managers (Isle of Man) Limited	Man, Isle of
White Rock Insurance PCC (Isle of Man) Limited	Man, Isle of
Aon Solutions Ltd	Mauritius
Aon Mauritius Holdings	Mauritius
Aon Mexico Intermediario de Reaseguro, S.A. de C.V.	Mexico
E.R.N. Evaluacion de Riesgos Naturales y Antropogenicos, S.A. de C.V.	Mexico
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
Aon Mexico Holdings, S. de R.L. de C.V.	Mexico
Aon Risk Solutions Agente de Seguros y de Fianzas, 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

Name	Country	State/Province
Aon Acore S.a.r.l.	Morocco
Casablanca Intermediation Company S.a.r.l.	Morocco
Aon Delta Netherlands B.V.	Netherlands
Aon International B.V.	Netherlands
Aon 4 B.V.	Netherlands
Alexander & Alexander Holding B.V.	Netherlands
Aon Americas Holdings B.V.	Netherlands
Aon APAC 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 B.V.	Netherlands
Aon Investments Netherlands B.V.	Netherlands
Aon Holdings B.V.	Netherlands
Aon Holdings International B.V.	Netherlands
Aon Holdings Mid Europe 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
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 Reinsurance New Zealand Limited	New Zealand

Name	Country	State/Province
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 Norway AS	Norway
Cut-e Nordic AS	Norway
Aon Assessment (Norway) AS	Norway
Aon Majan LLC	Oman
Aon Benfield Panama S.A.	Panama
Aon Broking Services S.A.	Panama
Aon Solutions (PNG) Limited	Papua New Guinea
Aon Risk Services (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 Polska Services Sp. z o.o.	Poland
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.	Puerto Rico
Aon Risk Solutions of Puerto Rico, Inc.	Puerto Rico
Hewitt Insurance, Inc.	Puerto Rico
Aon Qatar LLC	Qatar
Aon Consulting Romania SRL	Romania
Aon Romania Broker de Asigurare - Reasigurare SRL	Romania

Name	Country	State/Province
Aon Rus Insurance Brokers LLC	Russia
Aon Rus LLC	Russia
Aon Reinsurance Solutions Saudi Arabia LLC	Saudi Arabia
Aon Hewitt Saudi Arabia LLC	Saudi Arabia
Aon Arabia Insurance Brokers LLC	Saudi Arabia
Aon Insurance Agencies Pte. Ltd.	Singapore
Aon Randolph Singapore Pte.	Singapore
Aon Global Operations SE (Singapore Branch)	Singapore
Alexander & Alexander (Asia) Holdings Pte Ltd	Singapore
Aon Reinsurance Solutions Asia Pte. Ltd.	Singapore
Aon Solutions Singapore Pte. Ltd.	Singapore
Aon Insurance Managers (Singapore) Pte Ltd	Singapore
Aon Singapore (Broking Centre) Pte. Ltd.	Singapore
Aon Singapore Center for Innovation, Strategy and Management Pte Ltd	Singapore
Aon Singapore Pte. Ltd.	Singapore
Stenhouse (South East Asia) Private Limited	Singapore
Aon Randolph Singapore 2 Pte. Ltd.	Singapore
Aon Randolph Singapore 3 Pte. Ltd.	Singapore
Aon Bratislava s.r.o.	Slovakia
Aon Central and Eastern Europe a.s. (Slovakia Branch)	Slovakia
Mafube Risk and Insurance Consultants (Pty) Ltd	South Africa
TM Insurance Brokers (Pty) Ltd	South Africa
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
Newshelf 1151 (RF) (Pty) Ltd	South Africa
Fundación Aon Espana	Spain

Name	Country	State/Province
Aon Reinsurance Iberia Correduria de Reaseguros, S.A.U.	Spain
Aon Iberia Correduria de Seguros y Reaseguros, S.A.U.	Spain
Aon Marketing Directo, S.A.U.	Spain
Aon Southern Europe y Cia, S.L.	Spain
Aon Consulting Services SA	Spain
Grupo Innovac Sociedad Correduría de Seguros, S.A.	Spain
Inspiring Benefits, S.L.	Spain
One Underwriting Agencia de Suscripsión, S.L.U.	Spain
CoverWallet Innovations, S.L.U.	Spain
Aon Global Risk Consulting AB	Sweden
Aon Solutions Sweden AB	Sweden
Aon Sweden AB	Sweden
Aon Assessment (Sweden) AB	Sweden
Aon Insurance Managers (Switzerland) AG	Switzerland
Aon Schweiz AG	Switzerland
Assimedia SA	Switzerland
Aon Reinsurance Italia S.p.A., Milano, Succursale di Maroggia (Switzerland Branch)	Switzerland
Aon Management Consulting Taiwan Ltd.	Taiwan
Aon Taiwan Ltd.	Taiwan
Aon Solutions (Thailand) Ltd.	Thailand
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 Energy Caribbean Limited	Trinidad and Tobago
Aon Solutions Turkey Danismanlik A.S.	Turkey
Aon Sigorta ve Reasurans Brokerligi ve A.S.	Turkey
J.S. Johnson & Company (Turks & Caicos) Limited	Turks And Caicos Islands

Name	Country	State/Province
Aon Ukraine LLC	Ukraine
Aon Finland Oy (Rep. office) (Ukraine Branch)	Ukraine
Aon (DIFC) Gulf Limited	United Arab Emirates
Aon Reinsurance Solutions MENA Limited	United Arab Emirates
Aon Solutions Middle East Limited	United Arab Emirates
Aon Solutions Middle East Limited (Abu Dhabi branch)	United Arab Emirates
Aon Management Services (Middle East) Limited	United Arab Emirates
Aon Middle East Co LLC	United Arab Emirates
Aon Retirement Solutions Limited	United Arab Emirates
Cut-e Consult DMCC	United Arab Emirates
Stroz Friedberg Risk Management Limited	United Arab Emirates
Aon Middle East Consulting LLC	United Arab Emirates
McLagan Partners, Inc. (Dubai Branch)	United Arab Emirates
Aon Neudorf Finance S.a.r.l. (Dubai Branch)	United Arab Emirates
Aon Investments Europe Limited	United Kingdom
Aon Russell Limited	United Kingdom
Aon Finance UK 3 Limited	United Kingdom
Aon Finance UK 4 Limited	United Kingdom
Aon Minet Pension Trustees Limited	United Kingdom
Aon Finance UK 5 Limited	United Kingdom
Acumen Credit Insurance Brokers Limited	United Kingdom
Alexander Clay	United Kingdom
Aon ANZ Holdings Limited	United Kingdom
Aon Assessment (UK) Limited	United Kingdom
Aon UK Holdings Limited	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

Name	Country	State/Province
Aon Global Holdings 1 Limited	United Kingdom
Aon Global Holdings 2 Limited	United Kingdom
Aon Global Holdings plc	United Kingdom
Aon Solutions UK Limited	United Kingdom
Aon Holdings Limited	United Kingdom
Aon Overseas Holdings Limited	United Kingdom
Aon Pension Trustees Limited	United Kingdom
Aon Global Limited	United Kingdom
Aon Risk Services (NI) Limited	United Kingdom
Aon Securities 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 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
Gotham Digital Science Ltd	United Kingdom
Henderson Insurance Brokers Limited	United Kingdom
Henderson Risk Management Limited	United Kingdom
Aon Investments Limited	United Kingdom

Name	Country	State/Province
Aon Global Holdings Intermediaries Limited	United Kingdom
International Space Brokers Europe Limited	United Kingdom
International Space Brokers Limited	United Kingdom
McLagan (Aon) Limited	United Kingdom
Minet Group	United Kingdom
Portus Consulting Limited	United Kingdom
Portus Online LLP	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 Finance UK 1 Limited	United Kingdom
Aon Randolph UK Limited	United Kingdom
Aon Finance UK 2 Limited	United Kingdom
McLagan Partners, Inc. (UK Branch)	United Kingdom
One Underwriting B.V. (UK Branch)	United Kingdom
Aon Belgium B.V. (UK Branch)	United Kingdom
Blanch Americas Inc.	United States	Delaware
E.W. Blanch International Inc.	United States	Delaware
Access Plans USA, Inc.	United States	Oklahoma
Affinity Insurance Services, Inc.	United States	Pennsylvania
AIS Affinity Insurance Agency, Inc.	United States	California
AIS Insurance Agency, Inc.	United States	Washington
Alexander Reinsurance Intermediaries, Inc.	United States	New York
Allen Insurance Associates, Inc.	United States	California
Alliance HealthCard of Florida, Inc.	United States	Georgia
Alliance HealthCard, Inc.	United States	Georgia
American Insurance Services Corp.	United States	Texas
AMXH, LLC	United States	Delaware

Name	Country	State/Province
Aon Benefit Solutions Inc.	United States	Oklahoma
Aon Fac, Inc.	United States	Illinois
Aon Reinsurance Holdings, Inc.	United States	Delaware
Aon Re, Inc.	United States	Illinois
Aon Chile Holdings, LLC	United States	Delaware
Aon Consulting & Insurance Services	United States	California
Aon Consulting, Inc.	United States	New York
Aon Consulting, Inc.	United States	New Jersey
Aon Corporation	United States	Delaware
Aon Edge Insurance Agency, Inc.	United States	Florida
Aon Finance US 1, LLC	United States	Delaware
Aon Finance US 2, LLC	United States	Delaware
Aon Financial & Insurance Solutions, Inc.	United States	California
Aon Foundation	United States	Illinois
Aon Group, Inc.	United States	Maryland
Aon Investments USA Inc.	United States	Illinois
Aon Insurance Agency LLC	United States	Delaware
Aon Insurance Managers (USA) Inc.	United States	Vermont
Aon International Holdings, Inc.	United States	Maryland
Aon Life Agency of Texas, Inc.	United States	Texas
Aon Mexico Holdings, LLC	United States	Delaware
Aon Premium Finance, LLC	United States	Delaware
Aon Private Risk Management Insurance Agency, Inc.	United States	Illinois
Aon Property Risk Consulting, Inc.	United States	New York
Aon Realty Services, Inc.	United States	Pennsylvania
Aon Retirement Plan Advisors, LLC	United States	Delaware
Aon Risk Consultants, Inc.	United States	Illinois
Aon Risk Insurance Services West, Inc.	United States	California
Aon Risk Services (Holdings) of Latin America, Inc.	United States	Delaware

Name	Country	State/Province
Aon Risk Services (Holdings) of the Americas, Inc.	United States	Illinois
Aon Risk Services Central, Inc.	United States	Illinois
Aon Risk Services Companies, Inc.	United States	Maryland
Aon Risk Services Northeast, Inc.	United States	New York
Aon Risk Services South, Inc.	United States	North Carolina
Aon Risk Services Southwest, Inc.	United States	Texas
Aon Risk Services, Inc. of Florida	United States	Florida
Aon Risk Services, Inc. of Hawaii	United States	Hawaii
Aon Risk Services, Inc. of Maryland	United States	Maryland
Aon Risk Services, Inc. of Washington, D.C.	United States	District of Columbia
Aon Securities LLC	United States	Delaware
Aon Service Corporation	United States	Illinois
Aon Services Group, Inc.	United States	Delaware
Aon Special Risk Resources, Inc.	United States	Delaware
Aon TC Holdings, Inc.	United States	New Jersey
Aon Trust Company LLC	United States	Illinois
Aon Underwriting Managers, Inc.	United States	Delaware
Aon US Holdings 2, Inc.	United States	Delaware
Aon US Holdings, Inc.	United States	Delaware
Aon Ward Financial Corporation	United States	Ohio
Aon/Albert G. Ruben Insurance Services, Inc.	United States	California
ARM International Corp.	United States	New York
ARM International Insurance Agency Corp.	United States	Ohio
ARMRISK CORP.	United States	New Jersey
AS Holdings, Inc.	United States	Delaware
ASPN Insurance Agency, LLC	United States	Delaware
Association of Rural and Small Town Americans	United States	Missouri
Assurance Licensing Services, Inc.	United States	Illinois
B E P International Corp.	United States	New Jersey

Name	Country	State/Province
Benefit Marketing Solutions, L.L.C.	United States	Oklahoma
BMS Insurance Agency, L.L.C.	United States	Oklahoma
Bowes & Company, Inc., of New York	United States	New York
Cammack Health LLC	United States	New York
Cananwill Corporation	United States	Delaware
Cananwill, Inc.	United States	Pennsylvania
Cananwill, Inc.	United States	California
CEREP III Secondary Manager, LLC	United States	Delaware
CFSSG Real Estate Partners I, LLC	United States	Delaware
CFSSG Real Estate Partners II, LLC	United States	Delaware
CIF-H GP LLC	United States	Delaware
Citadel Insurance Managers, Inc.	United States	California
Coalition for Benefits Equality and Choice	United States	California
Custom Benefit Programs, Inc.	United States	New Jersey
cut-e USA Inc.	United States	New York
Elysium Digital, L.L.C.	United States	Delaware
Financial & Professional Risk Solutions, Inc.	United States	Illinois
Futurity Group, Inc.	United States	Nevada
Gotham Digital Science, LLC	United States	Delaware
GPE IV Korea Feeder General Partner, LLC	United States	Delaware
GTCR/AAM Blocker Corp.	United States	Delaware
HCI Townsend USA Fund Managers LLC	United States	Delaware
Healthy Paws Pet Insurance LLC	United States	Washington
Aon Solutions US, LLC	United States	Delaware
Aon North America, Inc.	United States	Delaware
Huntington T. Block Insurance Agency, Inc.	United States	District of Columbia
Impact Forecasting, L.L.C.	United States	Illinois
INPOINT, INC.	United States	Illinois
International Risk Management (Americas), Inc.	United States	Ohio

Name	Country	State/Province
International Space Brokers, Inc.	United States	Virginia
IRM/GRC Holding Inc.	United States	Delaware
JDPT Manager, LLC	United States	Delaware
Johnson Rooney Welch, Inc.	United States	California
K & K Insurance Group, Inc.	United States	Indiana
KVT GP, LLC	United States	Delaware
Lake Tahoe II GP, LLC	United States	Delaware
Lake Tahoe III GP, LLC	United States	Delaware
Lake Tahoe IV GP, LLC	United States	Delaware
McLagan Partners Asia, Inc.	United States	Delaware
McLagan Partners, Inc.	United States	Delaware
Farmington Administrative Services, LLC	United States	Connecticut
Minet Holdings Inc.	United States	New York
Minet Re North America, Inc.	United States	Georgia
Modern Survey, Inc.	United States	Minnesota
Muirfield Underwriters, Ltd.	United States	Delaware
Paragon Strategic Solutions Inc.	United States	Delaware
PathWise Solutions Group LLC	United States	Delaware
Penn Square I, LLC	United States	Delaware
Penn Square II, LLC	United States	Delaware
Penn Square Manager I, LLC	United States	Delaware
Penn Square Manager II, LLC	United States	Delaware
PGOF I, LLC	United States	Delaware
PGOF Manager I, LLC	United States	Ohio
Premier Auto Finance, Inc.	United States	Delaware
Private Equity Partnership Structures I, LLC	United States	Delaware
Protective Marketing Enterprises, Inc.	United States	Tennessee
SA Special Situations General Partner, LLC	United States	Delaware
Scritch Inc.	United States	Texas

Name	Country	State/Province
Specialty Benefits, Inc.	United States	Indiana
Strategic Manager-III, LLC	United States	Delaware
Stroz Friedberg Inc.	United States	Delaware
Stroz Friedberg Investigations LLC	United States	Delaware
Stroz Friedberg, LLC	United States	New York
The Key West Saxon Group, LLC	United States	Florida
The Townsend Group, LLC	United States	Ohio
Townsend Alpha Manager I, LLC	United States	Delaware
Townsend Alpha Manager II, LLC	United States	Delaware
Townsend Alpha Manager III, LLC	United States	Delaware
Townsend Holdings LLC	United States	Delaware
Townsend REF GP, LLC	United States	Delaware
TownSquare Alpha Manager I-A, LLC	United States	Delaware
TTG Core Plus Investments, LLC	United States	Delaware
TTG German Investments I, LLC	United States	Ohio
TTG Manager, LLC	United States	Delaware
Underwriters Marine Services, Inc.	United States	Louisiana
Ward Financial Group, Inc.	United States	Ohio
West Lake General Partner, LLC	United States	Delaware
West Lake II GP, LLC	United States	Delaware
White Rock (District of Columbia) PCC Ltd.	United States	District of Columbia
White Rock USA Ltd.	United States	Vermont
Worldwide Integrated Services Company	United States	Texas
Wrapid Specialty, Inc.	United States	California
WT Government Services, LLC	United States	Delaware
WT Technologies, LLC	United States	Delaware
Townsend Great Lakes and Plains GP, LLC	United States	Delaware
Townsend Strategic Ventures GP, LLC	United States	Delaware
CoverWallet, Inc.	United States	Delaware

Name	Country	State/Province
CoverWallet Science, Inc.	United States	Delaware
Aon Advantage Funds Holding Corporation	United States	Delaware
Aon Advantage Funds LLC	United States	Delaware
Aon IP Advantage Fund GP LLC	United States	Delaware
Townsend Opportunity Zone Fund GP, LLC	United States	Delaware
Aon KHF Fund GP LLC	United States	Delaware
Aon IP Advantage Blocker LLC	United States	Delaware
Aon IP Advantage Fund LP	United States	Delaware
Membership Leasing Trust	United States	Delaware
Crescent Meadow, LLC	United States	Delaware
NJM Fund GP, LLC	United States	Delaware
KKT GP, LLC	United States	Delaware
Aon M&G IP Credit Fund GP LLC	United States	Delaware
Aon Investments Holdco LLC	United States	Delaware
Aon Private Credit Opportunities GP LLC	United States	Delaware
TTG FRELD General Partner, LLC	United States	Delaware
East Sea GP, LLC	United States	Delaware
Aon Latin America S.A.	Uruguay
Marinaro Dundas SA	Uruguay
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	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	2.85% Senior Notes due 2027 2.05% Senior Notes due 2031 2.60% Senior Notes due 2031 5.00% Senior Notes due 2032 2.90% Senior Notes due 2051 3.90% Senior Notes due 2052
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 17, 2023, 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, 2022.

/s/ ERNST & YOUNG LLP

Chicago, Illinois

February 17, 2023

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 17, 2023	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 17, 2023	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, 2022 (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 17, 2023

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, 2022 (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 17, 2023

XML

Cover - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 16, 2023	Jun. 30, 2022
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
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			$ 57,066,496,679
Entity Common Stock, Shares Outstanding		205,142,379
Documents Incorporated by Reference	Portions of the registrant’s proxy statement for its 2023 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	2022
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 2.85% Senior Notes due 2027
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.85% Senior Notes due 2027
Trading Symbol	AON27
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 Corporation and Aon Global Holdings plc’s 5.00% Senior Notes due 2032
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.00% Senior Notes due 2032
Trading Symbol	AON32
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
Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052
Trading Symbol	AON52
Security Exchange Name	NYSE

XML

Audit Information	12 Months Ended
	Dec. 31, 2022
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, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue
Total revenue	$ 12,479	$ 12,193	$ 11,066
Expenses
Compensation and benefits	6,477	6,738	5,905
Information technology	509	477	444
Premises	289	327	291
Depreciation of fixed assets	151	179	167
Amortization and impairment of intangible assets	113	147	246
Other general expense	1,271	2,235	1,232
Total operating expenses	8,810	10,103	8,285
Operating income	3,669	2,090	2,781
Interest income	18	11	6
Interest expense	(406)	(322)	(334)
Other income (expense)	(125)	152	13
Income before income taxes	3,156	1,931	2,466
Income tax expense	510	623	448
Net income	2,646	1,308	2,018
Less: Net income attributable to noncontrolling interests	57	53	49
Net income attributable to Aon shareholders	$ 2,589	$ 1,255	$ 1,969
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 12.23	$ 5.59	$ 8.49
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 12.14	$ 5.55	$ 8.45
Weighted average ordinary shares outstanding - basic (in shares)	211.7	224.7	231.9
Weighted average ordinary shares outstanding - diluted (in shares)	213.2	226.1	233.1

XML

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 2,646	$ 1,308	$ 2,018
Less: Net income attributable to noncontrolling interests	57	53	49
Net income attributable to Aon shareholders	2,589	1,255	1,969
Other comprehensive income (loss), net of tax:
Change in fair value of financial instruments	(13)	1	13
Foreign currency translation adjustments	(528)	(289)	263
Postretirement benefit obligation	(211)	277	(101)
Total other comprehensive income (loss)	(752)	(11)	175
Less: Other comprehensive income (loss) attributable to noncontrolling interests	0	(1)	3
Total other comprehensive income (loss) attributable to Aon shareholders	(752)	(10)	172
Comprehensive income attributable to Aon shareholders	$ 1,837	$ 1,245	$ 2,141

XML

Consolidated Statements of Financial Position - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 690	$ 544
Short-term investments	452	292
Receivables, net	3,035	3,094
Fiduciary assets	15,900	14,386
Other current assets	646	716
Total current assets	20,723	19,032
Goodwill	8,292	8,434
Intangible assets, net	447	492
Fixed assets, net	558	529
Operating lease right-of-use assets	699	786
Deferred tax assets	824	766
Prepaid pension	652	1,366
Other non-current assets	509	512
Total assets	32,704	31,917
Current liabilities
Accounts payable and accrued liabilities	2,114	2,192
Short-term debt and current portion of long-term debt	945	1,164
Fiduciary liabilities	15,900	14,386
Other current liabilities	1,347	1,331
Total current liabilities	20,306	19,073
Long-term debt	9,825	8,228
Non-current operating lease liabilities	693	772
Deferred tax liabilities	99	401
Pension, other postretirement, and postemployment liabilities	1,186	1,375
Other non-current liabilities	1,024	910
Total liabilities	33,133	30,759
Equity (deficit)
Ordinary shares - $0.01 nominal value Authorized: 500.0 shares (issued: 2022 - 205.4; 2021 - 214.8)	2	2
Additional paid-in capital	6,864	6,624
Accumulated deficit	(2,772)	(1,694)
Accumulated other comprehensive loss	(4,623)	(3,871)
Total Aon shareholders' equity (deficit)	(529)	1,061
Noncontrolling interests	100	97
Total equity (deficit)	(429)	1,158
Total liabilities and equity (deficit)	$ 32,704	$ 31,917

XML

Consolidated Statements of Financial Position (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
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)	205,400,000	214,800,000

XML

Consolidated Statements of Shareholders' Equity (Deficit) - USD ($) shares in Millions, $ in Millions	Total	Ordinary Shares and Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Loss, Net of Tax	Non-controlling Interests
Beginning Balance (in shares) at Dec. 31, 2019		232.1
Beginning Balance at Dec. 31, 2019	$ 3,443	$ 6,154	$ 1,248	$ (4,033)	$ 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 repurchased (in shares)		(8.5)
Shares repurchased	(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)
Net purchases of shares from noncontrolling interests	(9)	$ (3)			(6)
Dividends paid to noncontrolling interests on subsidiary common stock	(32)				(32)
Ending Balance (in shares) at Dec. 31, 2020		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 repurchased (in shares)		(12.4)
Shares repurchased	(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
Net purchases of shares from noncontrolling interests	(13)	$ (8)			(5)
Dividends paid to noncontrolling interests on subsidiary common stock	$ (38)				(38)
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
Increase (Decrease) in Shareholders' Equity
Net income	2,646		2,589		57
Shares issued — employee stock compensation plans (in shares)		1.7
Shares issued — employee stock compensation plans	(157)	$ (156)	(1)
Shares repurchased (in shares)		(11.1)
Shares repurchased	(3,203)		(3,203)
Share-based compensation expense	397	$ 397
Dividends to shareholders	(463)		(463)
Net change in fair value of financial instruments	(13)			(13)
Net foreign currency translation adjustments	(528)			(528)	0
Net postretirement benefit obligation	(211)			(211)
Net purchases of shares from noncontrolling interests	(2)	$ (1)			(1)
Dividends paid to noncontrolling interests on subsidiary common stock	$ (53)				(53)
Ending Balance (in shares) at Dec. 31, 2022	205.4	205.4
Ending Balance at Dec. 31, 2022	$ (429)	$ 6,866	$ (2,772)	$ (4,623)	$ 100

XML

Consolidated Statements of Shareholders' Equity (Deficit) (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Dividends (in dollars per share)	$ 2.19	$ 1.99	$ 1.78

XML

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net income	$ 2,646	$ 1,308	$ 2,018
Adjustments to reconcile net income to cash provided by operating activities:
Gain from sales of businesses	(54)	(142)	(25)
Depreciation of fixed assets	151	179	167
Amortization and impairment of intangible assets	113	147	246
Share-based compensation expense	397	449	312
Deferred income taxes	(252)	11	9
Other, net	170	5	2
Change in assets and liabilities:
Receivables, net	(96)	(119)	108
Accounts payable and accrued liabilities	(22)	264	186
Current income taxes	216	200	(17)
Pension, other postretirement and postemployment liabilities	(53)	(124)	(143)
Other assets and liabilities	3	4	(80)
Cash provided by operating activities	3,219	2,182	2,783
Cash flows from investing activities
Proceeds from investments	110	58	64
Payments for investments	(107)	(91)	(97)
Net sales (purchases) of short-term investments - non fiduciary	(175)	15	(167)
Acquisition of businesses, net of cash and funds held on behalf of clients	(162)	(14)	(368)
Sale of businesses, net of cash and funds held on behalf of clients	81	218	30
Capital expenditures	(196)	(137)	(141)
Cash provided by (used for) investing activities	(449)	49	(679)
Cash flows from financing activities
Share repurchase	(3,203)	(3,543)	(1,763)
Proceeds from issuance of shares	58	55	44
Cash paid for employee taxes on withholding shares	(215)	(185)	(193)
Commercial paper issuances, net of repayments	(65)	671	(113)
Issuance of debt	1,967	1,495	991
Repayment of debt	(500)	(413)	(607)
Increase in fiduciary liabilities, net of fiduciary receivables	702	568	316
Cash dividends to shareholders	(463)	(447)	(412)
Noncontrolling interests and other financing activities	(71)	(125)	(35)
Cash used for financing activities	(1,790)	(1,924)	(1,772)
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(549)	(235)	297
Net increase in cash and cash equivalents and funds held on behalf of clients	431	72	629
Cash and cash equivalents and funds held on behalf of clients at beginning of year	6,645	6,573	5,944
Cash and cash equivalents and funds held on behalf of clients at end of year	7,076	6,645	6,573
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	690	544	884
Funds held on behalf of clients	6,386	6,101	5,689
Total cash and cash equivalents and funds held on behalf of clients	7,076	6,645	6,573
Supplemental disclosures:
Interest paid	351	328	326
Income taxes paid, net of refunds	$ 546	$ 412	$ 455

XML

Basis of Presentation

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying Consolidated Financial Statements and Notes thereto 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.

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, and foreign currency exchange rate movements 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.

Reclassification

Certain amounts in prior periods' Consolidated Financial Statements have been reclassified to conform to the current year presentation. In prior periods, commercial paper issuances and repayments were included in Issuance of debt and Repayment of debt, respectively, in the Consolidated Statements of Cash Flows. The net amount of commercial paper activity is now disclosed separately in Commercial paper issuances, net of repayments in the Consolidated Statements of Cash Flows. For the year ended December 31, 2021 and December 31, 2020, commercial paper issuances reclassified from Issuance of debt was $4,478 million and $3,162 million, respectively, and commercial paper repayments reclassified from Repayment of debt was $3,807 million and $3,275 million, respectively. Further information on the gross commercial paper activity for the current and prior year periods is included within the Liquidity and Financial Conditions section of Part II Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

In November 2022, Aon incurred a non-cash pension settlement charge of $170 million in connection with the purchase of an annuity for portions of its U.S. pension plans. Aon has separately classified the non-cash pension settlement charge within Other, net on the Consolidated Statement of Cash Flows as an adjustment to reconcile Net income to Cash provided by operating activities for the period ended December 31, 2022. Prior year comparable balances have been reclassified to conform with current year presentation. For the years ended December 31, 2021 and 2020, Aon incurred insignificant non-cash pension settlement charges of $5 million and $2 million, respectively, which were presented as changes in assets and liabilities held within Pension, other postretirement and other postemployment liabilities in the Consolidated Statements of Cash Flows. See Note 11 “Employee Benefits” for further information regarding the non-cash settlement charges incurred.

In prior periods, Cash paid for employee taxes on withholding shares were included with Proceeds from issuance of shares, and presented as Issuance of shares for employee benefit plans in the Consolidated Statements of Cash Flows. These items are now presented separately and prior year balances have been reclassified to conform to current year presentation. For the year ended December 31, 2021 and December 31, 2020, Proceeds from issuance of shares was $55 million and $44 million, respectively, and Cash paid for employee taxes on withholding shares was $185 million and $193 million, respectively.

XML

Summary of Significant Accounting Principles and Practices

12 Months Ended

Dec. 31, 2022

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. The customer

obtains control over the services promised by the Company at the completion of the insurance or reinsurance policy placement process once coverage is effective. 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 delivered 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. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. 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, Strategy and Technology Group, 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 Consumer Benefits 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. Revenue generated from the Company’s delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. 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, 2022, 2021, or 2020. 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 (expense) 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 generally 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, 2022, Cash and cash equivalents and Short-term investments totaled $1,142 million compared to $836 million at December 31, 2021, an increase of $306 million. Of the total balance, $115 million and $160 million was restricted as to its use at December 31, 2022 and 2021, respectively. Included within Short-term investments as of December 31, 2022 and 2021 balances, respectively, were £60.1 million ($72.5 million at December 31, 2022 exchanges rates) and £84.3 million ($112.8 million at December 31, 2021 exchange rates) of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator.

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 $6.4 billion and $6.1 billion at December 31, 2022 and 2021, respectively. Fiduciary receivables were $9.5 billion and $8.3 billion at December 31, 2022 and 2021, 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 $76 million and $90 million at December 31, 2022 and 2021, 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 purchase price 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 relative 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 the 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 customer-related and contract based, technology, tradenames, or other intangibles. 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 (expense) 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.

The Company releases income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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’s lease agreements may include initial direct costs and lease incentives. Initial direct costs are incremental costs of a lease that would not have been incurred if the lease had not been obtained and are included in the measurement of the ROU asset. Payments made to or on behalf of the Company, such as tenant improvement allowances, represent incentives that are considered reductions to the ROU asset and lease expense over the lease term.

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 applies 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 variable interest model to the entity, otherwise, the entity is evaluated under the voting interest model. When 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 hold a controlling financial interest over any VIEs that significantly impacts the VIE’s economic performance and the Company does not have rights to any significant benefits or obligations to absorb potentially significant losses. Thus, the Company does not consolidate any VIEs and Aon’s interest in VIEs as of December 31, 2022 was insignificant.

Aon holds a controlling financial interest in entities that are not VIEs when it, directly or indirectly holds more than 50% of the voting rights and the noncontrolling interest holders do not hold substantive participating rights.

New Accounting Pronouncements

All issued, but not yet effective, guidance has been deemed not applicable or not significant to the Consolidated Financial Statements.

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Revenue from Contracts with Customers

12 Months Ended

Dec. 31, 2022

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):

	Years Ended December 31
	2022		2021		2020
Commercial Risk Solutions	$	6,715	$	6,635	$	5,861
Reinsurance Solutions	2,190		1,997		1,814
Health Solutions	2,224		2,154		2,067
Wealth Solutions	1,367		1,426		1,341
Elimination	(17)		(19)		(17)
Total revenue	$	12,479	$	12,193	$	11,066

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
	2022		2021		2020
U.S.	$	5,666	$	5,459	$	5,032
Americas other than U.S.	1,137		1,027		911
U.K.	1,660		1,681		1,579
Ireland	99		127		84
Europe, Middle East, & Africa other than U.K. and Ireland	2,443		2,565		2,236
Asia Pacific	1,474		1,334		1,224
Total revenue	$	12,479	$	12,193	$	11,066

Contract Costs

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

	2022		2021
Balance at beginning of period	$	361	$	339
Additions	1,479		1,504
Amortization	(1,480)		(1,478)
Impairment	—		—
Foreign currency translation and other	(5)		(4)
Balance at end of period	$	355	$	361

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

	2022		2021
Balance at beginning of period	$	179	$	184
Additions	56		59
Amortization	(49)		(48)
Impairment	—		—
Foreign currency translation and other	(1)		(16)
Balance at end of period	$	185	$	179

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Other Financial Data

12 Months Ended

Dec. 31, 2022

Other Financial Data [Abstract]

Other Financial Data

Other Financial Data

Consolidated Statements of Income Information

Other Income (Expense)

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

	Years Ended December 31
	2022		2021		2020
Pension and other postretirement (1)	$	(179)	$	21	$	13
Foreign currency remeasurement	(14)		26		(12)
Extinguishment of debt	—		—		(7)
Financial instruments and other	4		(45)		(10)
Equity earnings	10		8		4
Gain from disposals of business	54		142		25
Total	$	(125)	$	152	$	13

(1) Refer to Note 11 “Employee Benefits” for further information.

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):

	2022		2021		2020
Balance at beginning of period	$	90	$	98	$	77
Provision	8		26		29
Accounts written off, net of recoveries	(18)		(37)		(6)
Foreign currency translation and other	(4)		3		(2)
Balance at end of period	$	76	$	90	$	98

Other Current Assets

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

As of December 31	2022		2021
Costs to fulfill contracts with customers (1)	$	355	$	361
Prepaid expenses	109		137
Taxes receivable	74		53
Other	108		165
Total	$	646	$	716

(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	2022		2021
Software	$	861	$	797
Leasehold improvements	409		425
Computer equipment	269		268
Furniture, fixtures, and equipment	267		279
Construction in progress	109		45
Other	34		33
Fixed assets, gross	1,949		1,847
Less: Accumulated depreciation	1,391		1,318
Fixed assets, net	$	558	$	529

Depreciation expense, which includes software amortization, was $151 million, $179 million, and $167 million for the years ended December 31, 2022, 2021, and 2020, respectively.

Other Non-current Assets

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

As of December 31	2022		2021
Costs to obtain contracts with customers (1)	$	185	$	179
Taxes receivable	109		95
Investments	60		64
Leases (2)	43		63
Other	112		111
Total	$	509	$	512

(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	2022		2021
Deferred revenue (1)	$	250	$	321
Taxes payable	193		149
Leases (2)	186		213
Other	718		648
Total	$	1,347	$	1,331

(1)$653 million and $553 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2022 and December 31, 2021, 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	2022		2021
Taxes payable (1)	$	795	$	609
Compensation and benefits	69		58
Deferred revenue	37		70
Leases (2)	28		46
Other	95		127
Total	$	1,024	$	910

(1)Includes $129 million and $145 million for the non-current portion of the transition tax as of December 31, 2022 and December 31, 2021, respectively. 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, 2022

Business Combination and Asset Acquisition [Abstract]

Acquisitions and Dispositions of Businesses

Acquisitions and Dispositions of Businesses

Completed Acquisitions

The Company completed five acquisitions during the year ended December 31, 2022 and two acquisitions during the year ended December 31, 2021. 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, 2022
Consideration transferred
Cash	$	161
Deferred and contingent consideration	9
Aggregate consideration transferred	$	170
Assets acquired
Goodwill	$	87
Intangible assets	78
Other assets (1)	25
Total assets acquired	190
Liabilities assumed
Total liabilities assumed	20
Net assets acquired	$	170

(1)     Includes Cash and cash equivalents of $2 million and funds held on behalf of clients of an insignificant amount.

Intangible assets acquired include technology as well as customer-related and contract-based assets. The intangible assets acquired as part of business acquisitions in 2022 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, 2022 were insignificant. Total revenue for these acquisitions included in the Company’s Consolidated Statement of Income for the year ended December 31, 2022 was approximately $25 million.

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.

2022 Acquisitions

On November 1, 2022, the Company completed the acquisition of 100% of the share capital of E.R.N. Evaluacion de Riesgos Naturales y Antropogenicos, S.A. de C.V., a Mexico-based firm in risk assessment modeling.

On September 12, 2022, the Company completed the purchase of certain assets of Praxiom Risk Management, a provider of professional risk management in the U.S.

On August 1, 2022, the Company completed the purchase of certain assets of U.S. Advisors, Inc., a broker based in the U.S.

On May 3, 2022, the Company completed the acquisition of 100% of the share capital of Karl Köllner group companies, a marine hull broker based in Germany.

On March 1, 2022, the Company completed the acquisition of Tyche, an actuarial software platform based in the U.K.

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.

Completed Dispositions

The Company completed three dispositions during the year ended December 31, 2022. The Company completed six dispositions during the year ended December 31, 2021 and one disposition during the year ended December 31, 2020.

The pretax gains recognized related to dispositions were $54 million, $142 million, and $25 million for the years ended December 31, 2022, December 31, 2021 and December 31, 2020, 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 dispositions were insignificant for the years ended December 31, 2022, December 31, 2021, and December 31, 2020, respectively.

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Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2022

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, 2022 and 2021, respectively, are as follows (in millions):

Balance as of January 1, 2021	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to current year disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434
Goodwill related to current year acquisitions	87
Goodwill related to current year disposals	(11)
Foreign currency translation and other	(218)
Balance as of December 31, 2022	$	8,292

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

As of December 31	2022						2021
	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	$	2,207	$	1,833	$	374	$	2,289	$	1,848	$	441
Technology and other	436		363		73		407		357		50
Tradenames	14		14		—		14		13		1
Total	$	2,657	$	2,210	$	447	$	2,710	$	2,218	$	492

Amortization expense and impairment charges from finite lived intangible assets were $113 million, $147 million, and $246 million for the years ended December 31, 2022, 2021, and 2020, respectively.

The estimated future amortization for finite-lived intangible assets as of December 31, 2022 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2023	$	99
2024	82
2025	68
2026	47
2027	34
Thereafter	117
Total	$	447

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Debt

12 Months Ended

Dec. 31, 2022

Debt Disclosure [Abstract]

Debt

Debt

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

As of December 31	2022		2021
Commercial paper	$	592	$	665
2.20% Senior Notes due November 2022 (1)	—		499
4.00% Senior Notes due November 2023 (2)	350		349
3.50% Senior Notes due June 2024	599		598
3.875% Senior Notes due December 2025	748		748
2.875% Senior Notes due May 2026 (EUR 500M)	530		563
8.205% Junior Subordinated Notes due January 2027	521		521
2.85% Senior Notes due May 2027	596		—
4.50% Senior Notes due December 2028	348		347
3.75% Senior Notes due May 2029	746		745
2.80% Senior Notes due May 2030	994		993
2.05% Senior Notes due August 2031	396		396
2.60% Senior Notes due December 2031	496		496
5.00% Senior Notes due September 2032	495		—
6.25% Senior Notes due September 2040	297		296
4.25% Senior Notes due December 2042	203		201
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	545		544
4.75% Senior Notes due May 2045	594		593
2.90% Senior Notes due August 2051	591		591
3.90% Senior Notes due February 2052	877		—
Other	5		—
Total debt	10,770		9,392
Less: Short-term debt and current portion of long-term debt	945		1,164
Total long-term debt	$	9,825	$	8,228

(1)The 2.20% Senior Notes due November 2022 were repaid in full on November 1, 2022.

(2)The 4.00% Senior Notes due November 2023 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2022.

Notes

In November 2022, Aon Global Limited’s $350 million 4.00% Senior Notes due November 2023 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2022.

In November 2022, Aon Corporation’s $500 million 2.20% Senior Notes matured and were repaid in full. 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 Statement of Financial Position as the date of maturity is in less than one year as of December 31, 2021.

On September 12, 2022, 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 $500 million of 5.00% Senior Notes due September 2032. The Company intends to use the net proceeds from the offering for general corporate purposes.

On February 28, 2022, Aon Corporation and Aon Global Holdings plc co-issued $600 million of 2.85% Senior Notes due May 2027 and $900 million of 3.90% Senior Notes due February 2052. The Company intends to use the net proceeds from the offering for general corporate purposes.

On December 2, 2021, Aon Corporation and Aon Global Holdings plc 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 and Aon Global Holdings plc 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 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. The redemption date was on February 16, 2021 and resulted in an insignificant loss due to extinguishment.

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. Each of the notes co-issued by Aon Corporation and Aon Global Holdings plc is fully and unconditionally guaranteed by Aon plc and Aon Global Limited. 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, 2022.

Repayments of total debt as of December 31, 2022 are as follows (in millions):

2023	$	946
2024	604
2025	750
2026	532
2027	1,121
Thereafter	6,956
Total Repayments	10,909
Unamortized discounts, premiums, and debt issuance costs	(139)
Total Debt	$	10,770

Revolving Credit Facilities

As of December 31, 2022, 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 2024. In aggregate, these two facilities provide approximately $1.8 billion in available credit.

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, 2022, 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, 2022.

Commercial Paper

Commercial paper may be issued in aggregate principal amounts of up to $1 billion under the U.S. Program and €625 million ($665 million at December 31, 2022 exchange rates) under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was approximately $1.8 billion at December 31, 2022. 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.

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	2022		2021
Commercial paper outstanding	$	592	$	665

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

	Years Ended December 31
	2022			2021
Weighted average commercial paper outstanding	$	499		$	273
Weighted average interest rate of commercial paper outstanding	1.42		%	0.01		%

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Lease Commitments

12 Months Ended

Dec. 31, 2022

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		2022		2021
Assets
Operating lease assets	Operating lease right-of-use assets	$	699	$	786
Finance lease assets	Other non-current assets	43		63
Total lease assets		$	742	$	849
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	163	$	194
Finance	Other current liabilities	23		19
Non-current lease liabilities
Operating	Non-current operating lease liabilities	693		772
Finance	Other non-current liabilities	28		46
Total lease liabilities		$	907	$	1,031

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

	Years Ended December 31
	2022		2021
Operating lease cost	$	204	$	217
Finance lease costs
Amortization of leased assets	28		26
Interest on lease liabilities	1		1
Variable lease cost	38		49
Short-term lease cost (1)	11		11
Sublease income	(29)		(31)
Net lease cost	$	253	$	273

(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	2022		2021
Weighted average remaining lease term (years)
Operating leases	6.7		6.9
Finance leases	2.5		3.6
Weighted average discount rate
Operating leases	3.1	%	2.8	%
Finance leases	1.0	%	1.0	%

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

	Years Ended December 31
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	231	$	244
Financing cash flows for finance leases	$	14	$	23
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	110	$	44
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	—
Operating lease ROU asset expense (1)	$	162	$	142
Changes in Non-current operating lease liabilities (1)	$	(79)	$	(125)

(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, 2022 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2023	$	175	$	23	$	198
2024	164		18		182
2025	135		10		145
2026	123		—		123
2027	108		—		108
Thereafter	235		—		235
Total undiscounted future minimum lease payments	940		51		991
Less: Imputed interest	(84)		—		(84)
Present value of lease liabilities	$	856	$	51	$	907

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		2022		2021
Assets
Operating lease assets	Operating lease right-of-use assets	$	699	$	786
Finance lease assets	Other non-current assets	43		63
Total lease assets		$	742	$	849
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	163	$	194
Finance	Other current liabilities	23		19
Non-current lease liabilities
Operating	Non-current operating lease liabilities	693		772
Finance	Other non-current liabilities	28		46
Total lease liabilities		$	907	$	1,031

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

	Years Ended December 31
	2022		2021
Operating lease cost	$	204	$	217
Finance lease costs
Amortization of leased assets	28		26
Interest on lease liabilities	1		1
Variable lease cost	38		49
Short-term lease cost (1)	11		11
Sublease income	(29)		(31)
Net lease cost	$	253	$	273

(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	2022		2021
Weighted average remaining lease term (years)
Operating leases	6.7		6.9
Finance leases	2.5		3.6
Weighted average discount rate
Operating leases	3.1	%	2.8	%
Finance leases	1.0	%	1.0	%

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

	Years Ended December 31
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	231	$	244
Financing cash flows for finance leases	$	14	$	23
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	110	$	44
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	—
Operating lease ROU asset expense (1)	$	162	$	142
Changes in Non-current operating lease liabilities (1)	$	(79)	$	(125)

(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, 2022 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2023	$	175	$	23	$	198
2024	164		18		182
2025	135		10		145
2026	123		—		123
2027	108		—		108
Thereafter	235		—		235
Total undiscounted future minimum lease payments	940		51		991
Less: Imputed interest	(84)		—		(84)
Present value of lease liabilities	$	856	$	51	$	907

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Income Taxes

12 Months Ended

Dec. 31, 2022

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
	2022		2021		2020
Income (loss) before income taxes:
Ireland	$	85	$	15	$	(86)
U.K.	502		549		634
U.S.	161		(818)		(28)
Other	2,408		2,185		1,946
Total	$	3,156	$	1,931	$	2,466
Income tax expense:
Current:
Ireland	$	2	$	2	$	2
U.K.	206		50		30
U.S. federal	195		197		126
U.S. state and local	43		72		22
Other	316		291		259
Total current tax expense	$	762	$	612	$	439
Deferred tax expense (benefit):
Ireland	$	—	$	(1)	$	(1)
U.K.	(152)		131		39
U.S. federal	(69)		(83)		(72)
U.S. state and local	(21)		(30)		(4)
Other	(10)		(6)		47
Total deferred tax expense (benefit)	$	(252)	$	11	$	9
Total income tax expense	$	510	$	623	$	448

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. The reconciliation of the income tax provisions based on the Irish statutory corporate tax rate of 25% to the provisions reflected in the Consolidated Financial Statements is as follows:

	Years Ended December 31
	2022	2021	2020
Statutory tax rate	25.0%	25.0%	25.0%
U.S. state income taxes, net of U.S. federal benefit	0.4	1.5	1.0
Taxes on international operations (1) (2)	(11.6)	(15.4)	(9.8)
Nondeductible expenses	2.4	3.3	2.1
Adjustments to prior year tax requirements	(7.0)	(0.2)	—
Deferred tax adjustments, including statutory rate changes	(0.5)	3.2	0.7
Deferred tax adjustments, international earnings	0.2	1.8	0.7
Adjustments to valuation allowances	1.9	(0.2)	—
Change in uncertain tax positions	8.6	2.1	1.5
Excess tax benefits related to shared based compensation (3)	(1.5)	(2.4)	(2.2)
Capital and other losses	(1.4)	—	(1.8)
Non-deductible transaction costs	—	1.1	1.3
Non-deductible termination fee	—	12.9	—
Other — net	(0.3)	(0.4)	(0.3)
Effective tax rate	16.2%	32.3%	18.2%

(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 25.0% at December 31, 2022, 2021, and 2020, 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)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 2022 and therefore recorded the impact of making the election.

(3)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.

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	2022		2021
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	952	$	581
Lease liabilities	178		207
Employee benefit plans	297		160
Other accrued expenses	100		132
Accrued interest	—		97
Federal and state benefit of interest from uncertain tax positions	57		45
Deferred revenue	26		36
Investment basis differences	30		25
Lease and service guarantees	1		1
Other	38		25
Total	1,679		1,309
Valuation allowance on deferred tax assets	(275)		(230)
Total	$	1,404	$	1,079
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(258)	$	(243)
Lease right-of-use asset	(151)		(173)
Deferred costs	(147)		(159)
Unremitted earnings	(38)		(58)
Other accrued expenses	(20)		(27)
Unrealized foreign exchange gains	(23)		(22)
Other	(42)		(32)
Total	$	(679)	$	(714)
Net deferred tax asset	$	725	$	365

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	2022		2021
Deferred tax assets — non-current	$	824	$	766
Deferred tax liabilities — non-current	(99)		(401)
Net deferred tax asset	$	725	$	365

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 tax credits and net operating losses, capital losses, and interest carryforwards. Valuation allowances increased by $45 million as of December 31, 2022, when compared to December 31, 2021. The change is primarily attributable to an increase in valuation allowances related to net operating losses and foreign tax credits.

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, 2022, the Company has accrued $38 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	2022		2021
U.K.
Operating loss carryforwards	$	608	$	41
Capital loss carryforwards	$	533	$	573
U.S.
Federal operating loss carryforwards	$	1	$	25
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	2,269	$	1,140
Federal foreign tax credit carryforwards	$	20	$	18
State operating loss carryforwards	$	473	$	398
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	1,187	$	551
Other Non-U.S.
Operating loss carryforwards	$	490	$	301
Capital loss carryforwards	$	8	$	35
Interest carryforwards	$	26	$	26
Other carryforwards	$	5	$	5

The U.K. operating losses and capital losses 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, 2022 have various carryforward periods and will begin to expire in 2023. Federal and state capital losses can be carried forward until 2023. Federal and state interest carryforwards have indefinite carryforward periods. Foreign tax credits can be carried forward for ten years and will begin to expire in 2028. Operating, capital losses, and other carryforwards in other non-U.S. jurisdictions have various carryforward periods and will begin to expire in 2023. 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. The Company has been granted a new incentive for the period October 1, 2022 to September 30, 2032. The new incentive provides for a reduced withholding tax rate and a reduced tax rate on certain income derived from services in Singapore, as long as certain conditions are met.

The benefit realized was approximately $115 million, $104 million, and $97 million during the years ended December 31, 2022, 2021, and 2020, respectively. The impact of this tax holiday on diluted earnings per share was $0.54, $0.46, and $0.42 during the years ended December 31, 2022, 2021, and 2020, respectively.

Uncertain Tax Positions

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

	2022		2021
Balance at January 1	$	347	$	321
Additions based on tax positions related to the current year	35		33
Additions for tax positions of prior years	226		7
Reductions for tax positions of prior years	(1)		(4)
Settlements	(1)		—
Business combinations	—		—
Lapse of statute of limitations	(5)		(10)
Foreign currency translation	—		—
Balance at December 31	$	601	$	347

The Company’s liability for uncertain tax positions as of December 31, 2022, 2021, and 2020, includes $535 million, $295 million, and $270 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 $40 million, $22 million, and $21 million in 2022, 2021, and 2020, respectively. The Company recorded a liability for interest and penalties of $181 million, $142 million, and $120 million as of December 31, 2022, 2021, and 2020, 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 2014. The Company has concluded income tax examinations in its primary non-U.S. jurisdictions through 2008.

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Shareholders' Equity (Deficit)

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Shareholders' Equity (Deficit)

Shareholders’ Equity (Deficit)

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., accumulated deficit). As of December 31, 2022 and 2021, the Company had distributable profits in excess of $29.0 billion and $32.7 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 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
	2022		2021
Shares repurchased	11.1		12.4
Average price per share	$	289.76	$	286.82
Repurchase costs recorded to accumulated deficit	$	3,203	$	3,543

At December 31, 2022, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $6.0 billion. Under the Repurchase Program, the Company has repurchased a total of 160.7 million shares for an aggregate cost of approximately $21.5 billion.

Weighted Average Ordinary Shares

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

	Years Ended December 31
	2022	2021	2020
Basic weighted average ordinary shares outstanding	211.7	224.7	231.9
Dilutive effect of potentially issuable shares	1.5	1.4	1.2
Diluted weighted average ordinary shares outstanding	213.2	226.1	233.1

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 0.8 million and 0.3 million shares excluded from the calculation in 2022 and 2021, respectively, and no shares excluded from the calculation in 2020.

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, 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	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	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)
Other comprehensive income (loss) before reclassifications:
Other comprehensive loss before reclassifications	(15)		(528)		(569)		(1,112)
Tax benefit (expense)	4		—		149		153
Other comprehensive loss before reclassifications, net	(11)		(528)		(420)		(959)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income (loss)	(2)		—		282		280
Tax expense	—		—		(73)		(73)
Amounts reclassified from accumulated other comprehensive income (loss), net	(2)		—		209		207
Net current period other comprehensive loss	(13)		(528)		(211)		(752)
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)

(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.

XML

Employee Benefits

12 Months Ended

Dec. 31, 2022

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
	2022		2021		2020
U.S.	$	108	$	103	$	87
U.K.	47		46		42
Netherlands and Canada	33		35		26
Total	$	188	$	184	$	155

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, 2022 and 2021, and a statement of the funded status as of December 31, 2022 and 2021, 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 88% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2022		2021		2022		2021		2022		2021
Change in projected benefit obligation
At January 1	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Service cost	1		1		—		—		—		—
Interest cost	83		65		73		57		19		12
Settlements	—		(14)		(283)		—		—		—
Actuarial (gain) loss	(1,418)		(292)		(607)		(103)		(322)		24
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(444)		(58)		—		—		(89)		(83)
As of December 31	$	2,946	$	4,919	$	2,180	$	3,164	$	1,094	$	1,531
Accumulated benefit obligation at end of year	$	2,946	$	4,919	$	2,180	$	3,164	$	1,079	$	1,504
Change in fair value of plan assets
At January 1	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Actual return on plan assets	(1,961)		(136)		(484)		211		(284)		46
Employer contributions	7		9		37		61		15		17
Settlements	—		(14)		(283)		—		—		—
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(559)		(76)		—		—		(83)		(83)
As of December 31	$	3,537	$	6,246	$	1,481	$	2,378	$	1,032	$	1,430
Market related value at end of year	$	3,537	$	6,246	$	1,794	$	2,174	$	1,032	$	1,430
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	591	$	1,327	$	(699)	$	(786)	$	(62)	$	(101)
Unrecognized prior-service cost	35		40		—		—		(6)		(6)
Unrecognized loss	1,726		1,215		1,305		1,551		443		489
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

The benefit obligation decreased primarily as a result of increases in the discount rates in 2022 as compared to 2021. The value of plan assets decreased as a result of negative asset returns, predominately in the U.K, and overall weaker exchange rates versus the U.S. Dollar. The U.K. pension assets are concentrated in fixed income and annuities which were disproportionately negatively impacted by the rising interest rate environment. The U.K. hedging strategy continues to perform as expected and the related pension plans remain over-funded. Net actuarial gains decreased the benefit obligation in 2021 primarily due to the increase in the discount rates.

In November 2022, to further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. The transaction settled $280 million of benefit obligations using $280 million of assets.

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
	2022		2021		2022		2021		2022		2021
Prepaid benefit cost (1)	$	612	$	1,344	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(42)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(20)		(16)		(657)		(734)		(57)		(96)
Accumulated other comprehensive loss	1,761		1,255		1,305		1,551		437		483
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

(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, 2022 and 2021 consist of (in millions):

	U.K.				U.S.				Other
	2022		2021		2022		2021		2022		2021
Net loss	$	1,726	$	1,215	$	1,305	$	1,551	$	443	$	489
Prior service cost (income)	35		40		—		—		(6)		(6)
Total	$	1,761	$	1,255	$	1,305	$	1,551	$	437	$	483

In 2022, U.S. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $2.2 billion, an ABO of $2.2 billion, and plan assets with a fair value of $1.5 billion. U.K. plans with a PBO and an ABO in excess of the fair value of plan assets had a PBO of $114 million, an ABO of $114 million and, plan assets with a fair value of $93 million. Other plans with a PBO in excess of the fair value of plan assets had a PBO of $1.1 billion and plan assets with a fair value of $1.0 billion, and other plans with an ABO in excess of the fair value of plan assets had an ABO of $220 million and plan assets with a fair value of $166 million.

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.

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
	2022		2021		2020		2022		2021		2020		2022		2021		2020
Service cost	$	1	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	83		65		88		73		57		85		19		12		19
Expected return on plan assets, net of administration expenses	(134)		(137)		(159)		(108)		(130)		(134)		(33)		(32)		(34)
Amortization of prior-service cost	2		2		2		—		—		1		—		—		—
Amortization of net actuarial loss	29		32		30		61		78		68		13		15		12
Net periodic benefit (income) cost	(19)		(37)		(39)		26		5		20		(1)		(5)		(3)
Settlement expense	—		5		2		170		—		—		—		—		—
Total net periodic benefit cost (income)	$	(19)	$	(32)	$	(37)	$	196	$	5	$	20	$	(1)	$	(5)	$	(3)

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.

In November 2022, to further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. 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 of approximately $170 million in 2022.

Transfer payments from certain U.K. pension plans exceeded the plan’s service and interest cost in 2021 and 2020. 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), and approximately £2 million in 2020 ($2 million using December 31, 2020 exchange rates).

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

	U.K.		U.S. (1)		Other
	2022	2021	2022	2021	2022	2021
Discount rate	4.89%	1.96%	4.82 - 5.03%	2.23 - 2.8%	3.23 - 5.19%	1.00 - 2.97%
Rate of compensation increase	3.59 - 4.09%	3.62 - 4.12%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.44%	2.52%	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
	2022	2021	2020	2022	2021	2020	2022	2021	2020
Discount rate	1.85%	1.20%	1.89%	1.67 - 2.25%	1.12 - 1.79%	2.36 - 2.76%	0.84 - 2.58%	0.28 - 2.00%	0.74 - 2.90%
Expected return on plan assets, net of administration expenses	2.34%	2.04%	2.74%	2.03 - 5.28%	2.65- 6.56%	3.30%-7.04%	1.80 - 3.15%	1.70 - 2.65%	2.10 - 3.10%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	3.24 - 3.74%	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 5.28% 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 2023.

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, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2022		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)	$	42	$	42	$	—	$	—
Equity investments:
Equity securities	64		64		—		—
Equity derivatives	(6)		—		(6)		—
Pooled funds (2)	293		—		—		—
Fixed income investments:
Corporate bonds	192		—		192		—
Government and agency bonds	149		124		25		—
Pooled funds (2)	507		—		—		—
Other investments:
Real estate (2) (3)	113		—		—		—
Alternative investments (2) (4)	127		—		—		—
Total	$	1,481	$	230	$	211	$	—

			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	$	—

(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, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	336	$	336	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(548)		—		(548)		—
Government and agency bonds	1,593		1,593		—		—
Annuities	1,403		—		—		1,403
Pooled funds (2)	139		—		—		—
Other investments:
Real estate (2) (4)	97		—		—		—
Pooled funds (2) (5)	517		—		—		—
Total	$	3,537	$	1,929	$	(548)	$	1,403

			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

(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, 2022 and December 31, 2021 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2021	$	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchase, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	2,305
Actual return on plan assets:
Relating to assets still held at December 31, 2022	(674)
Purchases, sales and settlements-net	—
Foreign exchange	(228)
Balance at December 31, 2022	$	1,403

The fair values of the Company’s other major pension plan assets at December 31, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	30	$	30	$	—	$	—
Equity investments:
Equity securities	53		53		—		—
Pooled funds (2)	211		—		—		—
Fixed income investments:
Government and agency bonds	225		225		—		—
Derivatives	(3)		—		(3)		—
Pooled funds (2)	462		—		—		—
Other investments:
Alternative investments (2) (3)	42		—		—		—
Real estate (2) (4)	12		—		—		—
Total	$	1,032	$	308	$	(3)	$	—

			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	$	—	$	—

(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, 2022, the weighted average targeted allocation for the U.S. plans was 30% for equity investments, 54% for fixed income investments, and 16% 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, 2022, the weighted average targeted allocation for the U.K. and non-U.S. plans was 6% for equity investments, 86% for fixed income investments, and 8% for other investments.

Cash Flows

Contributions

Based on current assumptions, in 2023, the Company expects to contribute approximately $4 million, $43 million, and $14 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, 2022 (in millions):

	U.K.		U.S.		Other
2023	$	153	$	157	$	46
2024	$	157	$	158	$	47
2025	$	161	$	158	$	49
2026	$	166	$	162	$	50
2027	$	170	$	155	$	51
2028 - 2032	$	905	$	754	$	274

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, 2022 and 2021 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2022		2021
Accumulated projected benefit obligation	$	83	$	109
Fair value of plan assets	14		17
Funded status	(69)		(92)
Unrecognized prior-service credit	(1)		(1)
Unrecognized (gain) loss	(19)		2
Net amount recognized	$	(89)	$	(91)

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

	2022	2021	2020
Net periodic benefit cost recognized (millions)	$3	$5	$4
Weighted-average discount rate used to determine future benefit obligations	4.94 - 5.19%	2.52 - 3.06%	2.10 - 2.58%
Weighted-average discount rate used to determine net periodic benefit costs	1.97 - 2.69%	1.45 - 2.68%	2.93 - 3.25%

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 2023 is $0.8 million net gain and $0.2 million of prior-service credit.

•To contribute $5 million to fund significant other postretirement benefit plans during 2023.

•Estimated future benefit payments will be approximately $5 million each year for 2023 through 2027, and $27 million in aggregate for 2028-2032.

XML

Share-Based Compensation Plans

12 Months Ended

Dec. 31, 2022

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
	2022		2021		2020
Restricted share units	$	251	$	204	$	186
Performance share awards	134		189		116
Employee share purchase plans and other (1)	12		56		10
Total share-based compensation expense	397		449		312
Tax benefit	83		87		61
Share-based compensation expense, net of tax	$	314	$	362	$	251

(1) 2021 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):

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	3,075	$	203
Granted	1,117	$	279
Vested	(1,154)	$	187
Forfeited	(175)	$	219
Non-vested balance at December 31, 2022	2,863	$	238

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

The weighted-average grant date fair value of the Company's RSU awards granted during the years ended December 31, 2022, December 31, 2021, and December 31, 2020 was $279, $253, and $185, respectively. The fair value of RSUs that vested during 2022, 2021, and 2020 was $216 million, $189 million, and $190 million, respectively.

Unamortized deferred compensation expense amounted to $466 million as of December 31, 2022, with a remaining weighted average amortization period of approximately 2.0 years.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of adjusted diluted 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, reduced by the present value of estimated dividends foregone during the vesting period. 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 status of the Company's PSAs at 100% of the targeted amount (shares in thousands, except fair value):

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	1,298	$	181
Granted	300	$	311
Vested	(444)	$	163
Forfeited	(18)	$	217
Non-vested balance at December 31, 2022	1,136	$	222

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

The per share weighted-average grant date fair value of the Company's PSA awards granted during the years ended December 31, 2022, December 31, 2021, and December 31, 2020 was $311, $225, and $163, respectively. The payout of shares in 2022 with respect to the PSA awards granted in 2019 based on performance for the three-year performance period ended 2021 was, in aggregate, 888 thousand shares. The fair value of PSAs that vested during 2022, 2021, and 2020 was $145 million, $112 million, and $121 million, respectively.

Unamortized compensation expense, based on current performance levels, amounted to $126 million as of December 31, 2022, with a remaining weighted average amortization period of approximately 1.3 years.

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Derivatives and Hedging

12 Months Ended

Dec. 31, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives and Hedging

Derivatives and HedgingThe 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 (expense) 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
As of December 31	2022		2021		2022		2021		2022		2021
Foreign exchange contracts
Accounted for as hedges	$	618	$	629	$	12	$	27	$	2	$	—
Not accounted for as hedges (3)	312		412		—		2		1		—
Total	$	930	$	1,041	$	12	$	29	$	3	$	—

(1)Included within Other current assets ($3 million in 2022 and $21 million in 2021) or Other non-current assets ($9 million in 2022 and $8 million in 2021).

(2)Included within Other current liabilities ($2 million in 2022) or Other non-current liabilities ($1 million in 2022).

(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):

	2022		2021		2020
(Loss) gain recognized in Accumulated other comprehensive loss	$	(15)	$	—	$	1

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
	2022		2021		2020
Total revenue	$	2	$	(3)	$	(14)
Compensation and benefits	—		1		—
Interest expense	—		—		(1)
Total	$	2	$	(2)	$	(15)

The Company estimates that approximately $10 million of pretax loss currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

The Company recorded a gain of $11 million in 2022, a loss of $24 million in 2021, and a gain of $1 million in 2020 in Other income (expense) for foreign exchange derivatives not designated or qualifying as hedges.

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Fair Value Measurements and Financial Instruments

12 Months Ended

Dec. 31, 2022

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, 2022 and December 31, 2021 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	3,323	$	3,323	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	19	$	—	$	19	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	9	$	—	$	9	$	—

			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	$	—

(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 2022 or 2021. 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 2022, 2021, or 2020.

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):

	2022				2021
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	350	$	347	$	499	$	507
Long-term debt	$	9,825	$	8,745	$	8,228	$	9,204

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Claims, Lawsuits and Other Contingencies

12 Months Ended

Dec. 31, 2022

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 is not subject to current matters in connection with which the Company believes (1) material loss (including interest and costs) is probable, (2) material loss (including interest and costs) is reasonably possible (that is, more than remote but not probable), or (3) there exists the reasonable possibility of material loss (including interest and costs) greater than the accrued amount. The Company includes in the current matters described below certain matters in which it believes a material loss is remote but in which the claimed amounts are significant. Although management at present believes that the ultimate outcome of such matters, 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

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 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 ERISA. 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, and oral argument took place on December 7, 2022. Aon believes it has meritorious defenses and intends to vigorously defend itself against these claims and appeal.

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 cooperated 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 ($35 million at December 31, 2022 exchange rates). In December 2022, the High Court in England granted an anti-suit injunction, restricting the 43 individuals who previously filed a motion in the Circuit Court of the 11th Judicial Circuit in and for Miami-Dade County, Florida, from continuing litigation in the Circuit Court of the 11th Judicial Circuit against Aon. Aon believes that it has meritorious defenses and intends to vigorously defend itself against the remaining claims.

Settled/Closed 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 claimed damages of approximately NZD 320 million ($202 million at December 31, 2022 exchange rates) plus interest and costs. In December 2022, the case was settled with no admission of liability on the part of Aon.

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 Ireland Reorganization, on April 1, 2020, Aon plc and Aon Global Holdings plc 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).

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 $74 million at December 31, 2022, and $75 million at December 31, 2021. 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 $173 million at December 31, 2022 compared to $153 million at December 31, 2021.

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Segment Information

12 Months Ended

Dec. 31, 2022

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, 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
2022	$	1,300	$	519	$	120	$	155	$	9	$	279	$	218
2021	$	1,378	$	563	$	121	$	180	$	7	$	293	$	214

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Summary of Significant Accounting Principles and Practices (Policies)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Basis of Accounting

Basis of PresentationThe accompanying Consolidated Financial Statements and Notes thereto 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.

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, and foreign currency exchange rate movements 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. The customer

obtains control over the services promised by the Company at the completion of the insurance or reinsurance policy placement process once coverage is effective. 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 delivered 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. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. 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, Strategy and Technology Group, 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 Consumer Benefits 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. Revenue generated from the Company’s delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. 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, 2022, 2021, or 2020. 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 (expense) 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 generally 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 purchase price 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 relative 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 the 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 customer-related and contract based, technology, tradenames, or other intangibles. 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 (expense) 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.

The Company releases income tax effects from Accumulated other comprehensive loss using the portfolio approach.

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’s lease agreements may include initial direct costs and lease incentives. Initial direct costs are incremental costs of a lease that would not have been incurred if the lease had not been obtained and are included in the measurement of the ROU asset. Payments made to or on behalf of the Company, such as tenant improvement allowances, represent incentives that are considered reductions to the ROU asset and lease expense over the lease term.

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 applies 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 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 variable interest model to the entity, otherwise, the entity is evaluated under the voting interest model. When 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 hold a controlling financial interest over any VIEs that significantly impacts the VIE’s economic performance and the Company does not have rights to any significant benefits or obligations to absorb potentially significant losses. Thus, the Company does not consolidate any VIEs and Aon’s interest in VIEs as of December 31, 2022 was insignificant.

Aon holds a controlling financial interest in entities that are not VIEs when it, directly or indirectly holds more than 50% of the voting rights and the noncontrolling interest holders do not hold substantive participating rights.

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.

New Accounting Pronouncements

New Accounting Pronouncements

All issued, but not yet effective, guidance has been deemed not applicable or not significant to the Consolidated Financial Statements.

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Summary of Significant Accounting Principles and Practices (Tables)

12 Months Ended

Dec. 31, 2022

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	2022						2021
	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	$	2,207	$	1,833	$	374	$	2,289	$	1,848	$	441
Technology and other	436		363		73		407		357		50
Tradenames	14		14		—		14		13		1
Total	$	2,657	$	2,210	$	447	$	2,710	$	2,218	$	492

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Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2022

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

	Years Ended December 31
	2022		2021		2020
Commercial Risk Solutions	$	6,715	$	6,635	$	5,861
Reinsurance Solutions	2,190		1,997		1,814
Health Solutions	2,224		2,154		2,067
Wealth Solutions	1,367		1,426		1,341
Elimination	(17)		(19)		(17)
Total revenue	$	12,479	$	12,193	$	11,066

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
	2022		2021		2020
U.S.	$	5,666	$	5,459	$	5,032
Americas other than U.S.	1,137		1,027		911
U.K.	1,660		1,681		1,579
Ireland	99		127		84
Europe, Middle East, & Africa other than U.K. and Ireland	2,443		2,565		2,236
Asia Pacific	1,474		1,334		1,224
Total revenue	$	12,479	$	12,193	$	11,066

Schedule of Capitalized Contract Cost

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

	2022		2021
Balance at beginning of period	$	361	$	339
Additions	1,479		1,504
Amortization	(1,480)		(1,478)
Impairment	—		—
Foreign currency translation and other	(5)		(4)
Balance at end of period	$	355	$	361

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

	2022		2021
Balance at beginning of period	$	179	$	184
Additions	56		59
Amortization	(49)		(48)
Impairment	—		—
Foreign currency translation and other	(1)		(16)
Balance at end of period	$	185	$	179

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Other Financial Data (Tables)

12 Months Ended

Dec. 31, 2022

Other Financial Data [Abstract]

Schedule of Components of Other Income (Expense)

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

	Years Ended December 31
	2022		2021		2020
Pension and other postretirement (1)	$	(179)	$	21	$	13
Foreign currency remeasurement	(14)		26		(12)
Extinguishment of debt	—		—		(7)
Financial instruments and other	4		(45)		(10)
Equity earnings	10		8		4
Gain from disposals of business	54		142		25
Total	$	(125)	$	152	$	13

(1) Refer to Note 11 “Employee Benefits” for further information.

Schedule of Allowance for Doubtful Accounts

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

	2022		2021		2020
Balance at beginning of period	$	90	$	98	$	77
Provision	8		26		29
Accounts written off, net of recoveries	(18)		(37)		(6)
Foreign currency translation and other	(4)		3		(2)
Balance at end of period	$	76	$	90	$	98

Schedule of Other Current Assets

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

As of December 31	2022		2021
Costs to fulfill contracts with customers (1)	$	355	$	361
Prepaid expenses	109		137
Taxes receivable	74		53
Other	108		165
Total	$	646	$	716

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

Schedule of Components of Fixed Assets, Net

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

As of December 31	2022		2021
Software	$	861	$	797
Leasehold improvements	409		425
Computer equipment	269		268
Furniture, fixtures, and equipment	267		279
Construction in progress	109		45
Other	34		33
Fixed assets, gross	1,949		1,847
Less: Accumulated depreciation	1,391		1,318
Fixed assets, net	$	558	$	529

Schedule of Other Non-current Assets

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

As of December 31	2022		2021
Costs to obtain contracts with customers (1)	$	185	$	179
Taxes receivable	109		95
Investments	60		64
Leases (2)	43		63
Other	112		111
Total	$	509	$	512

(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	2022		2021
Deferred revenue (1)	$	250	$	321
Taxes payable	193		149
Leases (2)	186		213
Other	718		648
Total	$	1,347	$	1,331

(1)$653 million and $553 million was recognized in the Consolidated Statements of Income during the years ended December 31, 2022 and December 31, 2021, 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	2022		2021
Taxes payable (1)	$	795	$	609
Compensation and benefits	69		58
Deferred revenue	37		70
Leases (2)	28		46
Other	95		127
Total	$	1,024	$	910

(1)Includes $129 million and $145 million for the non-current portion of the transition tax as of December 31, 2022 and December 31, 2021, respectively. 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, 2022

Business Combination and Asset Acquisition [Abstract]

Schedule of 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, 2022
Consideration transferred
Cash	$	161
Deferred and contingent consideration	9
Aggregate consideration transferred	$	170
Assets acquired
Goodwill	$	87
Intangible assets	78
Other assets (1)	25
Total assets acquired	190
Liabilities assumed
Total liabilities assumed	20
Net assets acquired	$	170

(1)     Includes Cash and cash equivalents of $2 million and funds held on behalf of clients of an insignificant amount.

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Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2022

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, 2022 and 2021, respectively, are as follows (in millions):

Balance as of January 1, 2021	$	8,666
Goodwill related to current year acquisitions	17
Goodwill related to current year disposals	(37)
Foreign currency translation and other	(212)
Balance as of December 31, 2021	$	8,434
Goodwill related to current year acquisitions	87
Goodwill related to current year disposals	(11)
Foreign currency translation and other	(218)
Balance as of December 31, 2022	$	8,292

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	2022						2021
	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	$	2,207	$	1,833	$	374	$	2,289	$	1,848	$	441
Technology and other	436		363		73		407		357		50
Tradenames	14		14		—		14		13		1
Total	$	2,657	$	2,210	$	447	$	2,710	$	2,218	$	492

Schedule of Estimated Future Amortization Expense on Intangible Assets

The estimated future amortization for finite-lived intangible assets as of December 31, 2022 is as follows (in millions):

	Estimated Future Amortization
For the years ended
2023	$	99
2024	82
2025	68
2026	47
2027	34
Thereafter	117
Total	$	447

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Debt (Tables)

12 Months Ended

Dec. 31, 2022

Debt Disclosure [Abstract]

Schedule of Outstanding Debt

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

As of December 31	2022		2021
Commercial paper	$	592	$	665
2.20% Senior Notes due November 2022 (1)	—		499
4.00% Senior Notes due November 2023 (2)	350		349
3.50% Senior Notes due June 2024	599		598
3.875% Senior Notes due December 2025	748		748
2.875% Senior Notes due May 2026 (EUR 500M)	530		563
8.205% Junior Subordinated Notes due January 2027	521		521
2.85% Senior Notes due May 2027	596		—
4.50% Senior Notes due December 2028	348		347
3.75% Senior Notes due May 2029	746		745
2.80% Senior Notes due May 2030	994		993
2.05% Senior Notes due August 2031	396		396
2.60% Senior Notes due December 2031	496		496
5.00% Senior Notes due September 2032	495		—
6.25% Senior Notes due September 2040	297		296
4.25% Senior Notes due December 2042	203		201
4.45% Senior Notes due May 2043	247		247
4.60% Senior Notes due June 2044	545		544
4.75% Senior Notes due May 2045	594		593
2.90% Senior Notes due August 2051	591		591
3.90% Senior Notes due February 2052	877		—
Other	5		—
Total debt	10,770		9,392
Less: Short-term debt and current portion of long-term debt	945		1,164
Total long-term debt	$	9,825	$	8,228

(1)The 2.20% Senior Notes due November 2022 were repaid in full on November 1, 2022.

(2)The 4.00% Senior Notes due November 2023 were reclassified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as of December 31, 2022.

Schedule of Repayments of Long-term Debt

Repayments of total debt as of December 31, 2022 are as follows (in millions):

2023	$	946
2024	604
2025	750
2026	532
2027	1,121
Thereafter	6,956
Total Repayments	10,909
Unamortized discounts, premiums, and debt issuance costs	(139)
Total Debt	$	10,770

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	2022		2021
Commercial paper outstanding	$	592	$	665

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

	Years Ended December 31
	2022			2021
Weighted average commercial paper outstanding	$	499		$	273
Weighted average interest rate of commercial paper outstanding	1.42		%	0.01		%

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Lease Commitments (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Schedule of 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		2022		2021
Assets
Operating lease assets	Operating lease right-of-use assets	$	699	$	786
Finance lease assets	Other non-current assets	43		63
Total lease assets		$	742	$	849
Liabilities
Current lease liabilities
Operating	Other current liabilities	$	163	$	194
Finance	Other current liabilities	23		19
Non-current lease liabilities
Operating	Non-current operating lease liabilities	693		772
Finance	Other non-current liabilities	28		46
Total lease liabilities		$	907	$	1,031

Schedule of Lease, Cost

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

	Years Ended December 31
	2022		2021
Operating lease cost	$	204	$	217
Finance lease costs
Amortization of leased assets	28		26
Interest on lease liabilities	1		1
Variable lease cost	38		49
Short-term lease cost (1)	11		11
Sublease income	(29)		(31)
Net lease cost	$	253	$	273

(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	2022		2021
Weighted average remaining lease term (years)
Operating leases	6.7		6.9
Finance leases	2.5		3.6
Weighted average discount rate
Operating leases	3.1	%	2.8	%
Finance leases	1.0	%	1.0	%

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

	Years Ended December 31
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	231	$	244
Financing cash flows for finance leases	$	14	$	23
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	$	110	$	44
ROU assets obtained in exchange for new finance lease liabilities	$	—	$	—
Operating lease ROU asset expense (1)	$	162	$	142
Changes in Non-current operating lease liabilities (1)	$	(79)	$	(125)

(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.

Schedule of Lessee Operating Lease Liability Maturity

Maturity analysis of operating and finance leases as of December 31, 2022 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2023	$	175	$	23	$	198
2024	164		18		182
2025	135		10		145
2026	123		—		123
2027	108		—		108
Thereafter	235		—		235
Total undiscounted future minimum lease payments	940		51		991
Less: Imputed interest	(84)		—		(84)
Present value of lease liabilities	$	856	$	51	$	907

Schedule of Finance Lease, Liability, Maturity

Maturity analysis of operating and finance leases as of December 31, 2022 are as follows (in millions):

	Operating Leases		Finance Leases		Total
2023	$	175	$	23	$	198
2024	164		18		182
2025	135		10		145
2026	123		—		123
2027	108		—		108
Thereafter	235		—		235
Total undiscounted future minimum lease payments	940		51		991
Less: Imputed interest	(84)		—		(84)
Present value of lease liabilities	$	856	$	51	$	907

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Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of 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
	2022		2021		2020
Income (loss) before income taxes:
Ireland	$	85	$	15	$	(86)
U.K.	502		549		634
U.S.	161		(818)		(28)
Other	2,408		2,185		1,946
Total	$	3,156	$	1,931	$	2,466
Income tax expense:
Current:
Ireland	$	2	$	2	$	2
U.K.	206		50		30
U.S. federal	195		197		126
U.S. state and local	43		72		22
Other	316		291		259
Total current tax expense	$	762	$	612	$	439
Deferred tax expense (benefit):
Ireland	$	—	$	(1)	$	(1)
U.K.	(152)		131		39
U.S. federal	(69)		(83)		(72)
U.S. state and local	(21)		(30)		(4)
Other	(10)		(6)		47
Total deferred tax expense (benefit)	$	(252)	$	11	$	9
Total income tax expense	$	510	$	623	$	448

Schedule of Reconciliation of the Income Tax Provisions based on the U.S. Statutory Corporate Tax Rate to the Provisions Reflected in the Consolidated Financial Statements

	Years Ended December 31
	2022	2021	2020
Statutory tax rate	25.0%	25.0%	25.0%
U.S. state income taxes, net of U.S. federal benefit	0.4	1.5	1.0
Taxes on international operations (1) (2)	(11.6)	(15.4)	(9.8)
Nondeductible expenses	2.4	3.3	2.1
Adjustments to prior year tax requirements	(7.0)	(0.2)	—
Deferred tax adjustments, including statutory rate changes	(0.5)	3.2	0.7
Deferred tax adjustments, international earnings	0.2	1.8	0.7
Adjustments to valuation allowances	1.9	(0.2)	—
Change in uncertain tax positions	8.6	2.1	1.5
Excess tax benefits related to shared based compensation (3)	(1.5)	(2.4)	(2.2)
Capital and other losses	(1.4)	—	(1.8)
Non-deductible transaction costs	—	1.1	1.3
Non-deductible termination fee	—	12.9	—
Other — net	(0.3)	(0.4)	(0.3)
Effective tax rate	16.2%	32.3%	18.2%

(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 25.0% at December 31, 2022, 2021, and 2020, 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)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 2022 and therefore recorded the impact of making the election.

(3)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.

Schedule of 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	2022		2021
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$	952	$	581
Lease liabilities	178		207
Employee benefit plans	297		160
Other accrued expenses	100		132
Accrued interest	—		97
Federal and state benefit of interest from uncertain tax positions	57		45
Deferred revenue	26		36
Investment basis differences	30		25
Lease and service guarantees	1		1
Other	38		25
Total	1,679		1,309
Valuation allowance on deferred tax assets	(275)		(230)
Total	$	1,404	$	1,079
Deferred tax liabilities:
Intangibles and property, plant and equipment	$	(258)	$	(243)
Lease right-of-use asset	(151)		(173)
Deferred costs	(147)		(159)
Unremitted earnings	(38)		(58)
Other accrued expenses	(20)		(27)
Unrealized foreign exchange gains	(23)		(22)
Other	(42)		(32)
Total	$	(679)	$	(714)
Net deferred tax asset	$	725	$	365

Schedule of 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	2022		2021
Deferred tax assets — non-current	$	824	$	766
Deferred tax liabilities — non-current	(99)		(401)
Net deferred tax asset	$	725	$	365

Schedule of Operating and Capital Loss Carryforwards

The Company had the following carryforwards (in millions):

As of December 31	2022		2021
U.K.
Operating loss carryforwards	$	608	$	41
Capital loss carryforwards	$	533	$	573
U.S.
Federal operating loss carryforwards	$	1	$	25
Federal capital loss carryforwards	$	112	$	112
Federal interest carryforwards	$	2,269	$	1,140
Federal foreign tax credit carryforwards	$	20	$	18
State operating loss carryforwards	$	473	$	398
State capital loss carryforwards	$	123	$	123
State interest carryforwards	$	1,187	$	551
Other Non-U.S.
Operating loss carryforwards	$	490	$	301
Capital loss carryforwards	$	8	$	35
Interest carryforwards	$	26	$	26
Other carryforwards	$	5	$	5

Schedule of 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):

	2022		2021
Balance at January 1	$	347	$	321
Additions based on tax positions related to the current year	35		33
Additions for tax positions of prior years	226		7
Reductions for tax positions of prior years	(1)		(4)
Settlements	(1)		—
Business combinations	—		—
Lapse of statute of limitations	(5)		(10)
Foreign currency translation	—		—
Balance at December 31	$	601	$	347

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Shareholders' Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2022

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
	2022		2021
Shares repurchased	11.1		12.4
Average price per share	$	289.76	$	286.82
Repurchase costs recorded to accumulated deficit	$	3,203	$	3,543

Schedule of Components of Weighted Average Number of Shares Outstanding

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

	Years Ended December 31
	2022	2021	2020
Basic weighted average ordinary shares outstanding	211.7	224.7	231.9
Dilutive effect of potentially issuable shares	1.5	1.4	1.2
Diluted weighted average ordinary shares outstanding	213.2	226.1	233.1

Schedule of 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, 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	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	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)
Other comprehensive income (loss) before reclassifications:
Other comprehensive loss before reclassifications	(15)		(528)		(569)		(1,112)
Tax benefit (expense)	4		—		149		153
Other comprehensive loss before reclassifications, net	(11)		(528)		(420)		(959)
Amounts reclassified from accumulated other comprehensive income (loss):
Amounts reclassified from accumulated other comprehensive income (loss)	(2)		—		282		280
Tax expense	—		—		(73)		(73)
Amounts reclassified from accumulated other comprehensive income (loss), net	(2)		—		209		207
Net current period other comprehensive loss	(13)		(528)		(211)		(752)
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)

(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.

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Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

Schedule of 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
	2022		2021		2020
U.S.	$	108	$	103	$	87
U.K.	47		46		42
Netherlands and Canada	33		35		26
Total	$	188	$	184	$	155

Schedule of 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, 2022 and 2021, and a statement of the funded status as of December 31, 2022 and 2021, 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 88% of the Company’s projected benefit obligations.

	U.K.				U.S.				Other
(millions)	2022		2021		2022		2021		2022		2021
Change in projected benefit obligation
At January 1	$	4,919	$	5,406	$	3,164	$	3,380	$	1,531	$	1,625
Service cost	1		1		—		—		—		—
Interest cost	83		65		73		57		19		12
Settlements	—		(14)		(283)		—		—		—
Actuarial (gain) loss	(1,418)		(292)		(607)		(103)		(322)		24
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(444)		(58)		—		—		(89)		(83)
As of December 31	$	2,946	$	4,919	$	2,180	$	3,164	$	1,094	$	1,531
Accumulated benefit obligation at end of year	$	2,946	$	4,919	$	2,180	$	3,164	$	1,079	$	1,504
Change in fair value of plan assets
At January 1	$	6,246	$	6,652	$	2,378	$	2,276	$	1,430	$	1,497
Actual return on plan assets	(1,961)		(136)		(484)		211		(284)		46
Employer contributions	7		9		37		61		15		17
Settlements	—		(14)		(283)		—		—		—
Benefit payments	(195)		(189)		(167)		(170)		(45)		(47)
Foreign currency impact	(559)		(76)		—		—		(83)		(83)
As of December 31	$	3,537	$	6,246	$	1,481	$	2,378	$	1,032	$	1,430
Market related value at end of year	$	3,537	$	6,246	$	1,794	$	2,174	$	1,032	$	1,430
Amount recognized in Statement of Financial Position as of December 31
Funded status	$	591	$	1,327	$	(699)	$	(786)	$	(62)	$	(101)
Unrecognized prior-service cost	35		40		—		—		(6)		(6)
Unrecognized loss	1,726		1,215		1,305		1,551		443		489
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

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, 2022 and 2021 for the Company’s other significant postretirement benefit plans located in the U.S. and Canada (in millions):

	2022		2021
Accumulated projected benefit obligation	$	83	$	109
Fair value of plan assets	14		17
Funded status	(69)		(92)
Unrecognized prior-service credit	(1)		(1)
Unrecognized (gain) loss	(19)		2
Net amount recognized	$	(89)	$	(91)

Schedule of 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
	2022		2021		2022		2021		2022		2021
Prepaid benefit cost (1)	$	612	$	1,344	$	—	$	—	$	—	$	—
Accrued benefit liability - current (2)	(1)		(1)		(42)		(52)		(5)		(5)
Accrued benefit liability - non-current (3)	(20)		(16)		(657)		(734)		(57)		(96)
Accumulated other comprehensive loss	1,761		1,255		1,305		1,551		437		483
Net amount recognized	$	2,352	$	2,582	$	606	$	765	$	375	$	382

(1)Included in Prepaid pension.

(2)Included in Other current liabilities.

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

Schedule of 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, 2022 and 2021 consist of (in millions):

	U.K.				U.S.				Other
	2022		2021		2022		2021		2022		2021
Net loss	$	1,726	$	1,215	$	1,305	$	1,551	$	443	$	489
Prior service cost (income)	35		40		—		—		(6)		(6)
Total	$	1,761	$	1,255	$	1,305	$	1,551	$	437	$	483

Schedule of 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
	2022		2021		2020		2022		2021		2020		2022		2021		2020
Service cost	$	1	$	1	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	83		65		88		73		57		85		19		12		19
Expected return on plan assets, net of administration expenses	(134)		(137)		(159)		(108)		(130)		(134)		(33)		(32)		(34)
Amortization of prior-service cost	2		2		2		—		—		1		—		—		—
Amortization of net actuarial loss	29		32		30		61		78		68		13		15		12
Net periodic benefit (income) cost	(19)		(37)		(39)		26		5		20		(1)		(5)		(3)
Settlement expense	—		5		2		170		—		—		—		—		—
Total net periodic benefit cost (income)	$	(19)	$	(32)	$	(37)	$	196	$	5	$	20	$	(1)	$	(5)	$	(3)

Schedule of 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
	2022	2021	2022	2021	2022	2021
Discount rate	4.89%	1.96%	4.82 - 5.03%	2.23 - 2.8%	3.23 - 5.19%	1.00 - 2.97%
Rate of compensation increase	3.59 - 4.09%	3.62 - 4.12%	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%
Underlying price inflation	2.44%	2.52%	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
	2022	2021	2020	2022	2021	2020	2022	2021	2020
Discount rate	1.85%	1.20%	1.89%	1.67 - 2.25%	1.12 - 1.79%	2.36 - 2.76%	0.84 - 2.58%	0.28 - 2.00%	0.74 - 2.90%
Expected return on plan assets, net of administration expenses	2.34%	2.04%	2.74%	2.03 - 5.28%	2.65- 6.56%	3.30%-7.04%	1.80 - 3.15%	1.70 - 2.65%	2.10 - 3.10%
Rate of compensation increase	3.62 - 4.12%	3.22 - 3.72%	3.24 - 3.74%	N/A	N/A	N/A	1.00 - 3.00%	1.00 - 3.00%	1.00 - 3.00%

Schedule of Fair Values of Pension Plan Assets

The fair values of the Company’s U.S. pension plan assets at December 31, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
Asset Category	Balance at December 31, 2022		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)	$	42	$	42	$	—	$	—
Equity investments:
Equity securities	64		64		—		—
Equity derivatives	(6)		—		(6)		—
Pooled funds (2)	293		—		—		—
Fixed income investments:
Corporate bonds	192		—		192		—
Government and agency bonds	149		124		25		—
Pooled funds (2)	507		—		—		—
Other investments:
Real estate (2) (3)	113		—		—		—
Alternative investments (2) (4)	127		—		—		—
Total	$	1,481	$	230	$	211	$	—

			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	$	—

(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, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	336	$	336	$	—	$	—
Equity investments:
Pooled funds (2)	—		—		—		—
Fixed income investments:
Derivatives (3)	(548)		—		(548)		—
Government and agency bonds	1,593		1,593		—		—
Annuities	1,403		—		—		1,403
Pooled funds (2)	139		—		—		—
Other investments:
Real estate (2) (4)	97		—		—		—
Pooled funds (2) (5)	517		—		—		—
Total	$	3,537	$	1,929	$	(548)	$	1,403

			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

(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, 2022 and December 31, 2021, by asset category, are as follows (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	30	$	30	$	—	$	—
Equity investments:
Equity securities	53		53		—		—
Pooled funds (2)	211		—		—		—
Fixed income investments:
Government and agency bonds	225		225		—		—
Derivatives	(3)		—		(3)		—
Pooled funds (2)	462		—		—		—
Other investments:
Alternative investments (2) (3)	42		—		—		—
Real estate (2) (4)	12		—		—		—
Total	$	1,032	$	308	$	(3)	$	—

			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	$	—	$	—

(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.

Schedule of 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, 2022 and December 31, 2021 (in millions):

Fair Value Measurements Using Level 3 Inputs	Annuities
Balance at January 1, 2021	$	2,625
Actual return on plan assets:
Relating to assets still held at December 31, 2021	(286)
Purchase, sales and settlements-net	—
Foreign exchange	(34)
Balance at December 31, 2021	2,305
Actual return on plan assets:
Relating to assets still held at December 31, 2022	(674)
Purchases, sales and settlements-net	—
Foreign exchange	(228)
Balance at December 31, 2022	$	1,403

Schedule of Estimated Future Benefit Payments

Estimated future benefit payments for plans, not including voluntary one-time lump sum payments, are as follows at December 31, 2022 (in millions):

	U.K.		U.S.		Other
2023	$	153	$	157	$	46
2024	$	157	$	158	$	47
2025	$	161	$	158	$	49
2026	$	166	$	162	$	50
2027	$	170	$	155	$	51
2028 - 2032	$	905	$	754	$	274

Schedule of 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:

	2022	2021	2020
Net periodic benefit cost recognized (millions)	$3	$5	$4
Weighted-average discount rate used to determine future benefit obligations	4.94 - 5.19%	2.52 - 3.06%	2.10 - 2.58%
Weighted-average discount rate used to determine net periodic benefit costs	1.97 - 2.69%	1.45 - 2.68%	2.93 - 3.25%

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Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of 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
	2022		2021		2020
Restricted share units	$	251	$	204	$	186
Performance share awards	134		189		116
Employee share purchase plans and other (1)	12		56		10
Total share-based compensation expense	397		449		312
Tax benefit	83		87		61
Share-based compensation expense, net of tax	$	314	$	362	$	251

(1) 2021 includes expenses related to the Aon United Growth Ownership Plan.

Schedule of Restricted Share Unit Activity

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

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	3,075	$	203
Granted	1,117	$	279
Vested	(1,154)	$	187
Forfeited	(175)	$	219
Non-vested balance at December 31, 2022	2,863	$	238

(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 status of the Company's PSAs at 100% of the targeted amount (shares in thousands, except fair value):

	Shares	Fair Value (1)
Non-vested balance at December 31, 2021	1,298	$	181
Granted	300	$	311
Vested	(444)	$	163
Forfeited	(18)	$	217
Non-vested balance at December 31, 2022	1,136	$	222

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

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Derivatives and Hedging (Tables)

12 Months Ended

Dec. 31, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of 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
As of December 31	2022		2021		2022		2021		2022		2021
Foreign exchange contracts
Accounted for as hedges	$	618	$	629	$	12	$	27	$	2	$	—
Not accounted for as hedges (3)	312		412		—		2		1		—
Total	$	930	$	1,041	$	12	$	29	$	3	$	—

(1)Included within Other current assets ($3 million in 2022 and $21 million in 2021) or Other non-current assets ($9 million in 2022 and $8 million in 2021).

(2)Included within Other current liabilities ($2 million in 2022) or Other non-current liabilities ($1 million in 2022).

(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.

Schedule of Derivative Gains (Losses)

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

	2022		2021		2020
(Loss) gain recognized in Accumulated other comprehensive loss	$	(15)	$	—	$	1

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
	2022		2021		2020
Total revenue	$	2	$	(3)	$	(14)
Compensation and benefits	—		1		—
Interest expense	—		—		(1)
Total	$	2	$	(2)	$	(15)

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Fair Value Measurements and Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

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, 2022 and December 31, 2021 (in millions):

			Fair Value Measurements Using
	Balance at December 31, 2022		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)	$	3,323	$	3,323	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	19	$	—	$	19	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	9	$	—	$	9	$	—

			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	$	—

(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):

	2022				2021
As of December 31	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	350	$	347	$	499	$	507
Long-term debt	$	9,825	$	8,745	$	8,228	$	9,204

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Segment Information (Tables)

12 Months Ended

Dec. 31, 2022

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
2022	$	1,300	$	519	$	120	$	155	$	9	$	279	$	218
2021	$	1,378	$	563	$	121	$	180	$	7	$	293	$	214

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Basis of Presentation - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Issuance of debt		$ (1,967)	$ (1,495)	$ (991)
Repayment of debt		(500)	(413)	(607)
Non-cash pension settlement charges	$ 170		5	2
Proceeds from issuance of shares		58	55	44
Cash paid for employee taxes on withholding shares		$ 215	185	193
Revision of Prior Period, Reclassification, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Issuance of debt			4,478	3,162
Repayment of debt			3,807	3,275
Proceeds from issuance of shares			55	44
Cash paid for employee taxes on withholding shares			$ 185	$ 193

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Summary of Significant Accounting Principles and Practices - Additional Information (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Accounting Policies [Abstract]
Cash and cash equivalents and short-term investments	$ 1,142.0		$ 836.0
Cash and cash equivalents and short term investments, period increase (decrease)	306.0
Restricted cash and investments, current	115.0		160.0
Operating funds required to be held by the Company in the U.K.	72.5	£ 60.1	112.8	£ 84.3
Premium trust balances	6,400.0		6,100.0
Fiduciary receivables	9,500.0		8,300.0
Allowance for doubtful accounts	$ 76.0		$ 90.0		$ 98.0	$ 77.0

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Summary of Significant Accounting Principles and Practices - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2022
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, 2022
Customer-related and contract-based | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	7 years
Customer-related and contract-based | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	20 years
Technology and other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	5 years
Technology and other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	7 years
Tradenames | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	1 year
Tradenames | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of finite-lived intangible assets	3 years

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Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 12,479	$ 12,193	$ 11,066
U.S.
Disaggregation of Revenue [Line Items]
Total revenue	5,666	5,459	5,032
Americas other than U.S.
Disaggregation of Revenue [Line Items]
Total revenue	1,137	1,027	911
U.K.
Disaggregation of Revenue [Line Items]
Total revenue	1,660	1,681	1,579
Ireland
Disaggregation of Revenue [Line Items]
Total revenue	99	127	84
Europe, Middle East, & Africa other than U.K. and Ireland
Disaggregation of Revenue [Line Items]
Total revenue	2,443	2,565	2,236
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	1,474	1,334	1,224
Elimination
Disaggregation of Revenue [Line Items]
Total revenue	(17)	(19)	(17)
Commercial Risk Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	6,715	6,635	5,861
Reinsurance Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	2,190	1,997	1,814
Health Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	2,224	2,154	2,067
Wealth Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,367	$ 1,426	$ 1,341

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Revenue from Contracts with Customers - Contract Assets Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Capitalized Cost To Fulfill Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	$ 361	$ 339
Additions	1,479	1,504
Amortization	(1,480)	(1,478)
Impairment	0	0
Foreign currency translation and other	(5)	(4)
Balance at end of period	355	361
Capitalized Cost To Obtain Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	179	184
Additions	56	59
Amortization	(49)	(48)
Impairment	0	0
Foreign currency translation and other	(1)	(16)
Balance at end of period	$ 185	$ 179

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Other Financial Data - Schedule of Other Income (Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Other Financial Data [Abstract]
Pension and other postretirement	$ (179)	$ 21	$ 13
Foreign currency remeasurement	(14)	26	(12)
Extinguishment of debt	0	0	(7)
Financial instruments and other	4	(45)	(10)
Equity earnings	10	8	4
Gain from disposals of business	54	142	25
Total	$ (125)	$ 152	$ 13
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Total

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Other Financial Data - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 90	$ 98	$ 77
Provision	8	26	29
Accounts written off, net of recoveries	(18)	(37)	(6)
Foreign currency translation and other	(4)	3	(2)
Balance at end of period	$ 76	$ 90	$ 98

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Other Financial Data - Schedule of Other Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Financial Data [Abstract]
Costs to fulfill contracts with customers	$ 355	$ 361
Prepaid expenses	109	137
Taxes receivable	74	53
Other	108	165
Total	$ 646	$ 716

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Other Financial Data - Components of Fixed Assets, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 1,949	$ 1,847
Less: Accumulated depreciation	1,391	1,318
Fixed assets, net	558	529
Depreciation of fixed assets	151	179	$ 167
Software
Fixed Assets, net [Line Items]
Fixed assets, gross	861	797
Leasehold improvements
Fixed Assets, net [Line Items]
Fixed assets, gross	409	425
Computer equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	269	268
Furniture, fixtures and equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	267	279
Construction in progress
Fixed Assets, net [Line Items]
Fixed assets, gross	109	45
Other
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 34	$ 33

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Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Financial Data [Abstract]
Costs to obtain contracts with customers	$ 185	$ 179
Taxes receivable	109	95
Investments	60	64
Leases	43	63
Other	112	111
Total	$ 509	$ 512

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Other Financial Data - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Other Financial Data [Abstract]
Deferred revenue	$ 250	$ 321
Taxes payable	193	149
Leases	186	213
Other	718	648
Total	1,347	1,331
Deferred revenue recognized	$ 653	$ 553

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Other Financial Data - Schedule of Other Non-current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Financial Data [Abstract]
Taxes payable	$ 795	$ 609
Compensation and benefits	69	58
Deferred revenue	37	70
Leases	28	46
Other	95	127
Other non-current liabilities	1,024	910
Taxes payable, noncurrent, transition tax	$ 129	$ 145

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Acquisitions and Dispositions of Businesses - Completed Acquisitions (Details) $ in Millions		12 Months Ended
	Sep. 01, 2021 USD ($)	Dec. 31, 2022 USD ($) acquisition	Dec. 31, 2021 acquisition	Nov. 01, 2022	May 03, 2022	Dec. 22, 2021	Aug. 31, 2021
Business Acquisition [Line Items]
Number of business acquired under business combination | acquisition		5	2
Weighted average useful life		9 years
Revenues from acquisitions included in the Company's Consolidated Statement of Income		$ 25
E.R.N. Evaluacion de Riesgos Naturales y Antropogenicos, S.A. de C.V
Business Acquisition [Line Items]
Percentage of capital acquired				100.00%
Karl Köllner Group
Business Acquisition [Line Items]
Percentage of capital acquired					100.00%
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

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Acquisitions and Dispositions of Businesses - Schedule of Net Assets Acquired (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets acquired
Goodwill	$ 8,292	$ 8,434	$ 8,666
2022 And 2021 Acquisitions
Consideration transferred
Cash	161
Deferred and contingent consideration	9
Aggregate consideration transferred	170
Assets acquired
Goodwill	87
Intangible assets	78
Other assets	25
Total assets acquired	190
Liabilities assumed
Total liabilities assumed	20
Net assets acquired	170
Cash and cash equivalents	$ 2

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Acquisitions and Dispositions of Businesses - Completed Dispositions (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) disposition	Dec. 31, 2021 USD ($) disposition	Dec. 31, 2020 USD ($) disposition
Business Combination and Asset Acquisition [Abstract]
Number of dispositions | disposition	3	6	1
Gain from disposals of business | $	$ 54	$ 142	$ 25

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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, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 8,434	$ 8,666
Goodwill related to current year acquisitions	87	17
Goodwill related to current year disposals	(11)	(37)
Foreign currency translation and other	(218)	(212)
Balance at the end of the period	$ 8,292	$ 8,434

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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, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,657	$ 2,710
Accumulated Amortization and Impairment	2,210	2,218
Net Carrying Amount	447	492
Amortization and impairment of intangible assets	113	147	$ 246
Customer-related and contract-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,207	2,289
Accumulated Amortization and Impairment	1,833	1,848
Net Carrying Amount	374	441
Technology and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	436	407
Accumulated Amortization and Impairment	363	357
Net Carrying Amount	73	50
Tradenames
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	14	14
Accumulated Amortization and Impairment	14	13
Net Carrying Amount	$ 0	$ 1

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Goodwill and Other Intangible Assets - Schedule of estimated future amortization expense on intangible assets (Details) $ in Millions	Dec. 31, 2022 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2023	$ 99
2024	82
2025	68
2026	47
2027	34
Thereafter	117
Total	$ 447

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Debt - Summary of outstanding debt (Details)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)	Sep. 12, 2022 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 02, 2021 USD ($)	Aug. 23, 2021 USD ($)
Debt Instrument [Line Items]
Total debt	$ 10,770,000,000				$ 9,392,000,000
Less: Short-term debt and current portion of long-term debt	945,000,000				1,164,000,000
Total long-term debt	9,825,000,000				8,228,000,000
Other
Debt Instrument [Line Items]
Total debt	5,000,000				$ 0
2.20% Senior Notes due November 2022 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt					2.20%
Total debt	$ 0				$ 499,000,000
4.00% Senior Notes due November 2023 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.00%	4.00%
Total debt	$ 350,000,000				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	$ 599,000,000				598,000,000
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				748,000,000
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	$ 530,000,000				563,000,000
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
2.85% Senior Notes due May 2027 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.85%	2.85%		2.85%
Total debt	$ 596,000,000				0
Debt face value				$ 600,000,000
4.50% Senior Notes due December 2028 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	4.50%	4.50%
Total debt	$ 348,000,000				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	$ 746,000,000				745,000,000
2.80% Senior Notes due May 2030 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	2.80%	2.80%
Total debt	$ 994,000,000				993,000,000
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				396,000,000
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				496,000,000
Debt face value						$ 500,000,000
5.00% Senior Notes due September 2032 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	5.00%	5.00%	5.00%
Total debt	$ 495,000,000				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	$ 297,000,000				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	$ 203,000,000				201,000,000
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	$ 545,000,000				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	$ 594,000,000				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				591,000,000
Debt face value							$ 600,000,000
3.90% Senior Notes due February 2052 | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	3.90%	3.90%		3.90%
Total debt	$ 877,000,000				0
Debt face value				$ 900,000,000
Commercial paper
Debt Instrument [Line Items]
Total debt	$ 592,000,000				$ 665,000,000

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Debt - Narrative (Details)	Dec. 31, 2022 EUR (€) credit_facility	Dec. 31, 2022 USD ($) credit_facility	Sep. 12, 2022 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 02, 2021 USD ($)	Nov. 30, 2021 USD ($)	Aug. 23, 2021 USD ($)	Jan. 13, 2021 USD ($)
Debt Instrument [Line Items]
Number of credit facilities | credit_facility	2	2
4.00% Senior Notes due November 2023 | Senior Notes
Debt Instrument [Line Items]
Debt face value		$ 350,000,000
Debt interest rate percentage (as a percent)	4.00%	4.00%
2.20% Senior Notes due November 2022 | Senior Notes
Debt Instrument [Line Items]
Debt face value					$ 500,000,000		$ 500,000,000
Debt interest rate percentage (as a percent)					2.20%
U. S. Program | Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,000,000,000
European Program | Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	€ 625,000,000	$ 665,000,000
Senior Notes | 4.00% Senior Notes due November 2023
Debt Instrument [Line Items]
Debt interest rate percentage (as a percent)	4.00%	4.00%
Senior Notes | 2.20% Senior Notes due November 2022
Debt Instrument [Line Items]
Debt interest rate percentage (as a percent)					2.20%
Senior Notes | 5.00% Senior Notes due September 2032
Debt Instrument [Line Items]
Debt face value			$ 500,000,000
Debt interest rate percentage (as a percent)	5.00%	5.00%	5.00%
Senior Notes | 2.85% Senior Notes due May 2027
Debt Instrument [Line Items]
Debt face value				$ 600,000,000
Debt interest rate percentage (as a percent)	2.85%	2.85%		2.85%
Senior Notes | 3.90% Senior Notes due February 2052
Debt Instrument [Line Items]
Debt face value				$ 900,000,000
Debt interest rate percentage (as a percent)	3.90%	3.90%		3.90%
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%
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, available credit		$ 1,800,000,000
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, 2022 USD ($)
Debt Disclosure [Abstract]
2023	$ 946
2024	604
2025	750
2026	532
2027	1,121
Thereafter	6,956
Total Repayments	10,909
Unamortized discounts, premiums, and debt issuance costs	(139)
Total Debt	$ 10,770

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Debt - Schedule of Commercial Paper (Details) - Commercial paper - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Commercial paper outstanding	$ 592.0	$ 665.0
Weighted average commercial paper outstanding	$ 499.0	$ 273.0
Weighted average interest rate of commercial paper outstanding	1.42%	0.01%

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Lease Commitments - Assets and Liabilities of Lessee (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets
Operating lease assets	$ 699	$ 786
Finance lease assets	43	63
Total lease assets	$ 742	$ 849
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other non-current assets	Other non-current assets
Current lease liabilities
Operating	$ 163	$ 194
Finance	$ 23	$ 19
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	$ 693	$ 772
Finance	$ 28	$ 46
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities
Total lease liabilities	$ 907	$ 1,031

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Lease Commitments - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 204	$ 217
Finance lease costs
Amortization of leased assets	28	26
Interest on lease liabilities	1	1
Variable lease cost	38	49
Short-term lease cost	11	11
Sublease income	(29)	(31)
Net lease cost	$ 253	$ 273

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Lease Commitments - Lease Terms and Assumptions (Details)	Dec. 31, 2022	Dec. 31, 2021
Weighted average remaining lease term (years)
Operating leases	6 years 8 months 12 days	6 years 10 months 24 days
Finance leases	2 years 6 months	3 years 7 months 6 days
Weighted average discount rate
Operating leases	3.10%	2.80%
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, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$ 231	$ 244
Financing cash flows for finance leases	14	23
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	110	44
ROU assets obtained in exchange for new finance lease liabilities	0	0
Operating lease ROU asset expense	162	142
Changes in Non-current operating lease liabilities	$ (79)	$ (125)

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Lease Commitments - Lease Maturity (Details) $ in Millions	Dec. 31, 2022 USD ($)
Operating Leases
2023	$ 175
2024	164
2025	135
2026	123
2027	108
Thereafter	235
Total undiscounted future minimum lease payments	940
Less: Imputed interest	(84)
Present value of lease liabilities	856
Finance Leases
2023	23
2024	18
2025	10
2026	0
2027	0
Thereafter	0
Less: Imputed interest	51
Less: Imputed interest	0
Present value of lease liabilities	51
Total
2023	198
2024	182
2025	145
2026	123
2027	108
Thereafter	235
Total undiscounted future minimum lease payments	991
Less: Imputed interest	(84)
Present value of lease liabilities	$ 907

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Income Taxes - Income from continuing operations before income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income (loss) before income taxes:
Income before income taxes	$ 3,156	$ 1,931	$ 2,466
Current:
Total current tax expense	762	612	439
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(252)	11	9
Total income tax expense	510	623	448
Ireland
Income (loss) before income taxes:
Income before income taxes	85	15	(86)
Current:
Total current tax expense	2	2	2
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	0	(1)	(1)
U.K.
Income (loss) before income taxes:
Income before income taxes	502	549	634
Current:
Total current tax expense	206	50	30
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(152)	131	39
U.S. federal
Income (loss) before income taxes:
Income before income taxes	161	(818)	(28)
Current:
Total current tax expense	195	197	126
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(69)	(83)	(72)
U.S. state and local
Current:
Total current tax expense	43	72	22
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	(21)	(30)	(4)
Other
Income (loss) before income taxes:
Income before income taxes	2,408	2,185	1,946
Current:
Total current tax expense	316	291	259
Deferred tax expense (benefit):
Total deferred tax expense (benefit)	$ (10)	$ (6)	$ 47

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Income Taxes - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Statutory tax rate	25.00%	25.00%	25.00%
Increase in valuation allowance	$ 45
Unremitted earnings	38	$ 58
Benefit realized from tax holiday granted	$ 115	$ 104	$ 97
Earnings per share impact of tax holiday (in dollars per share)	$ 0.54	$ 0.46	$ 0.42
Unrecognized tax benefits that would impact effective tax rate	$ 535	$ 295	$ 270
Accrued potential interest and penalties	40	22	21
Liability recorded for interest and penalties	$ 181	$ 142	$ 120

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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, 2022	Dec. 31, 2021	Dec. 31, 2020
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%	25.00%
U.S. state income taxes, net of U.S. federal benefit	0.40%	1.50%	1.00%
Taxes on international operations	(11.60%)	(15.40%)	(9.80%)
Nondeductible expenses	2.40%	3.30%	2.10%
Adjustments to prior year tax requirements	(7.00%)	(0.20%)	0.00%
Deferred tax adjustments, including statutory rate changes	(0.50%)	3.20%	0.70%
Deferred tax adjustments, international earnings	0.20%	1.80%	0.70%
Adjustments to valuation allowances	1.90%	(0.20%)	0.00%
Change in uncertain tax positions	8.60%	2.10%	1.50%
Excess tax benefits related to shared based compensation	(1.50%)	(2.40%)	(2.20%)
Capital and other losses	(0.014)	0	(0.018)
Non-deductible transaction costs	0	0.011	0.013
Non-deductible termination fee	0.00%	12.90%	0.00%
Other — net	(0.30%)	(0.40%)	(0.30%)
Effective tax rate	16.20%	32.30%	18.20%

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Income Taxes - Components of Aon's deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss, capital loss, interest, and tax credit carryforwards	$ 952	$ 581
Lease liabilities	178	207
Employee benefit plans	297	160
Other accrued expenses	100	132
Accrued interest	0	97
Federal and state benefit of interest from uncertain tax positions	57	45
Deferred revenue	26	36
Investment basis differences	30	25
Lease and service guarantees	1	1
Other	38	25
Total	1,679	1,309
Valuation allowance on deferred tax assets	(275)	(230)
Total	1,404	1,079
Deferred tax liabilities:
Intangibles and property, plant and equipment	(258)	(243)
Lease right-of-use asset	(151)	(173)
Deferred costs	(147)	(159)
Unremitted earnings	(38)	(58)
Other accrued expenses	(20)	(27)
Unrealized foreign exchange gains	(23)	(22)
Other	(42)	(32)
Total	(679)	(714)
Net deferred tax asset	$ 725	$ 365

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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, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Deferred tax assets — non-current	$ 824	$ 766
Deferred tax liabilities — non-current	(99)	(401)
Net deferred tax asset	$ 725	$ 365

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Income Taxes Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
U.K.
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 608	$ 41
Capital loss carryforwards	533	573
U.S. Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1	25
Capital loss carryforwards	112	112
Interest Carryforward	2,269	1,140
Foreign tax credit carryforwards	20	18
U.S. State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	473	398
Capital loss carryforwards	123	123
Interest Carryforward	1,187	551
Other
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	490	301
Capital loss carryforwards	8	35
Interest Carryforward	26	26
Other carryforwards	$ 5	$ 5

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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, 2022	Dec. 31, 2021
Reconciliation of the Company's beginning and ending amount of unrecognized tax benefits
Balance at the beginning of the period	$ 347	$ 321
Additions based on tax positions related to the current year	35	33
Additions for tax positions of prior years	226	7
Reductions for tax positions of prior years	(1)	(4)
Settlements	(1)	0
Business combinations	0	0
Lapse of statute of limitations	(5)	(10)
Foreign currency translation	0	0
Balance at the end of the period	$ 601	$ 347

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Shareholders' Equity (Deficit) - Distributable Profits (Details) - USD ($) $ in Billions	Dec. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Distributable reserves available amount	$ 29.0	$ 32.7

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Shareholders' Equity (Deficit) - Ordinary Shares (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended				12 Months Ended		129 Months Ended
	Feb. 18, 2022	Nov. 30, 2020	Jun. 30, 2017	Nov. 30, 2014	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Apr. 30, 2012
Equity [Abstract]
Share repurchase authorization amount					$ 27,500,000,000		$ 27,500,000,000	$ 5,000,000,000
Share repurchase authorization amount, increase during period	$ 7,500,000,000	$ 5,000,000,000	$ 5,000,000,000	$ 5,000,000,000
Number of shares repurchased (in shares)					11.1	12.4	160.7
Average price per share (in dollars per share)					$ 289.76	$ 286.82
Repurchase costs recorded to accumulated deficit					$ 3,203,000,000	$ 3,543,000,000	$ 21,500,000,000
Remaining authorized repurchase amount					$ 6,000,000,000		$ 6,000,000,000

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Shareholders' Equity (Deficit) - Schedule of weighted average shares outstanding (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Basic weighted average ordinary shares outstanding (in shares)	211.7	224.7	231.9
Dilutive effect of potentially issuable shares (in shares)	1.5	1.4	1.2
Diluted weighted average ordinary shares outstanding (in shares)	213.2	226.1	233.1
Antidilutive securities excluded from computation of earnings per share (in shares)	0.8	0.3	0.0

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Shareholders' Equity (Deficit) - Components of Accumulated other comprehensive loss, net of related tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 1,158	$ 3,583	$ 3,443
Other comprehensive income (loss) before reclassifications	(1,112)	(63)	4
Tax benefit	153	(56)	62
Other comprehensive income (loss) before reclassifications, net	(959)	(119)	66
Amounts reclassified from accumulated other comprehensive income	280	144	140
Tax expense	(73)	(35)	(34)
Amounts reclassified from accumulated other comprehensive income (loss), net	207	109	106
Total other comprehensive income (loss) attributable to Aon shareholders	(752)	(10)	172
Ending Balance	(429)	1,158	3,583
Change in Fair Value of Investments
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	2	1	(12)
Other comprehensive income (loss) before reclassifications	(15)	0	1
Tax benefit	4	0	0
Other comprehensive income (loss) before reclassifications, net	(11)	0	1
Amounts reclassified from accumulated other comprehensive income	(2)	2	15
Tax expense	0	(1)	(3)
Amounts reclassified from accumulated other comprehensive income (loss), net	(2)	1	12
Total other comprehensive income (loss) attributable to Aon shareholders	(13)	1	13
Ending Balance	(11)	2	1
Foreign Currency Translation Adjustments
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,333)	(1,045)	(1,305)
Other comprehensive income (loss) before reclassifications	(528)	(290)	258
Tax benefit	0	2	2
Other comprehensive income (loss) before reclassifications, net	(528)	(288)	260
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	(528)	(288)	260
Ending Balance	(1,861)	(1,333)	(1,045)
Post-retirement Benefit Obligations
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(2,540)	(2,817)	(2,716)
Other comprehensive income (loss) before reclassifications	(569)	227	(255)
Tax benefit	149	(58)	60
Other comprehensive income (loss) before reclassifications, net	(420)	169	(195)
Amounts reclassified from accumulated other comprehensive income	282	142	125
Tax expense	(73)	(34)	(31)
Amounts reclassified from accumulated other comprehensive income (loss), net	209	108	94
Total other comprehensive income (loss) attributable to Aon shareholders	(211)	277	(101)
Ending Balance	(2,751)	(2,540)	(2,817)
AOCI attributable to parent
Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(3,871)	(3,861)	(4,033)
Ending Balance	$ (4,623)	$ (3,871)	$ (3,861)

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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, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	$ 188	$ 184	$ 155
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	108	103	87
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	47	46	42
Netherlands and Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense recognized for defined contribution savings plans	$ 33	$ 35	$ 26

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Employee Benefits - Pension Plans Narrative (Details) £ in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Nov. 30, 2022 USD ($)	Nov. 30, 2020 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percentage of the Company's projected benefit obligation			88.00%
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlement expense			$ 170
Non-cash settlement charge			(170)
Pension Plan | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefits obligations settled	$ 280
Defined benefit plan, plan assets for settlements	$ 280		283	$ 0
Plans with PBO in excess of plan assets, PBO			2,200	3,200
Plans with ABO in excess of the fair value of plan assets, ABO			2,200	3,200
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets			1,500	2,400
Settlement expense			(170)	0		$ 0
Non-cash settlement charge			170	0		0
Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets for settlements			0	14
Insurance contract, decrease in Prepaid pension assets		$ 94
Plans with PBO in excess of plan assets, PBO			114	17
Plans with ABO in excess of the fair value of plan assets, ABO			114	17
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets			93
Settlement expense			0	(5)	£ (3)	(2)	£ (2)
Non-cash settlement charge			0	5	£ 3	2	£ 2
Pension Plan | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets for settlements			0	0
Plans with PBO in excess of plan assets, PBO			1,100	1,500
Plans with ABO in excess of the fair value of plan assets, ABO			220	409
Plans with ABO in excess of the fair value of plan assets, fair value of plan assets			166	326
Plans with PBO in excess of plan assets, plan assets			1,000	1,400
Settlement expense			0	0		0
Non-cash settlement charge			$ 0	$ 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	1 Months Ended	12 Months Ended
	Nov. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
U.S.
Change in projected benefit obligation
Balance at the beginning of the Period		$ 3,164	$ 3,380
Service cost		0	0	$ 0
Interest cost		73	57	85
Settlements		(283)	0
Actuarial (gain) loss		(607)	(103)
Benefit payments		(167)	(170)
Foreign currency impact		0	0
Balance at the end of the period		2,180	3,164	3,380
Accumulated benefit obligation at end of year		2,180	3,164
Change in fair value of plan assets
Balance at the beginning of the period		2,378	2,276
Actual return on plan assets		(484)	211
Employer contributions		37	61
Settlements	$ (280)	(283)	0
Benefit payments		(167)	(170)
Foreign currency impact		0	0
Balance at the end of the period		1,481	2,378	2,276
Market related value at end of year		1,794	2,174
Funded status		(699)	(786)
Unrecognized prior-service cost		0	0
Unrecognized loss		1,305	1,551
Net amount recognized		606	765
U.K.
Change in projected benefit obligation
Balance at the beginning of the Period		4,919	5,406
Service cost		1	1	0
Interest cost		83	65	88
Settlements		0	(14)
Actuarial (gain) loss		(1,418)	(292)
Benefit payments		(195)	(189)
Foreign currency impact		(444)	(58)
Balance at the end of the period		2,946	4,919	5,406
Accumulated benefit obligation at end of year		2,946	4,919
Change in fair value of plan assets
Balance at the beginning of the period		6,246	6,652
Actual return on plan assets		(1,961)	(136)
Employer contributions		7	9
Settlements		0	(14)
Benefit payments		(195)	(189)
Foreign currency impact		(559)	(76)
Balance at the end of the period		3,537	6,246	6,652
Market related value at end of year		3,537	6,246
Funded status		591	1,327
Unrecognized prior-service cost		35	40
Unrecognized loss		1,726	1,215
Net amount recognized		2,352	2,582
Other
Change in projected benefit obligation
Balance at the beginning of the Period		1,531	1,625
Service cost		0	0	0
Interest cost		19	12	19
Settlements		0	0
Actuarial (gain) loss		(322)	24
Benefit payments		(45)	(47)
Foreign currency impact		(89)	(83)
Balance at the end of the period		1,094	1,531	1,625
Accumulated benefit obligation at end of year		1,079	1,504
Change in fair value of plan assets
Balance at the beginning of the period		1,430	1,497
Actual return on plan assets		(284)	46
Employer contributions		15	17
Settlements		0	0
Benefit payments		(45)	(47)
Foreign currency impact		(83)	(83)
Balance at the end of the period		1,032	1,430	$ 1,497
Market related value at end of year		1,032	1,430
Funded status		(62)	(101)
Unrecognized prior-service cost		(6)	(6)
Unrecognized loss		443	489
Net amount recognized		$ 375	$ 382

XML

Employee Benefits - Amounts recognized in the Consolidated Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	$ 652	$ 1,366
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	(42)	(52)
Accrued benefit liability - non-current	(657)	(734)
Accumulated other comprehensive loss	1,305	1,551
Net amount recognized	606	765
Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid pension	612	1,344
Accrued benefit liability - current	(1)	(1)
Accrued benefit liability - non-current	(20)	(16)
Accumulated other comprehensive loss	1,761	1,255
Net amount recognized	2,352	2,582
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	(57)	(96)
Accumulated other comprehensive loss	437	483
Net amount recognized	$ 375	$ 382

XML

Employee Benefits - Amounts recognized in Accumulated other comprehensive loss that have not yet been recognized (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
U.S.
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	$ 1,305	$ 1,551
Prior service cost (income)	0	0
Net amount recognized	1,305	1,551
U.K.
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	1,726	1,215
Prior service cost (income)	35	40
Net amount recognized	1,761	1,255
Other
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	443	489
Prior service cost (income)	(6)	(6)
Net amount recognized	$ 437	$ 483

XML

Employee Benefits - Components of net periodic benefit cost (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlement expense	$ (170)
Pension Plan | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	$ 0		$ 0
Interest cost	73	57		85
Expected return on plan assets, net of administration expenses	(108)	(130)		(134)
Amortization of prior-service cost	0	0		1
Amortization of net actuarial loss	61	78		68
Net periodic benefit (income) cost	26	5		20
Settlement expense	170	0		0
Total net periodic benefit cost (income)	196	5		20
Pension Plan | U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1	1		0
Interest cost	83	65		88
Expected return on plan assets, net of administration expenses	(134)	(137)		(159)
Amortization of prior-service cost	2	2		2
Amortization of net actuarial loss	29	32		30
Net periodic benefit (income) cost	(19)	(37)		(39)
Settlement expense	0	5	£ 3	2	£ 2
Total net periodic benefit cost (income)	(19)	(32)		(37)
Pension Plan | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0		0
Interest cost	19	12		19
Expected return on plan assets, net of administration expenses	(33)	(32)		(34)
Amortization of prior-service cost	0	0		0
Amortization of net actuarial loss	13	15		12
Net periodic benefit (income) cost	(1)	(5)		(3)
Settlement expense	0	0		0
Total net periodic benefit cost (income)	$ (1)	$ (5)		$ (3)

XML

Employee Benefits - Weighted-average assumptions used to determine future benefit obligations (Details) - Pension Plan	Dec. 31, 2022	Dec. 31, 2021
U.S. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.82%	2.23%
U.S. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	5.03%	2.80%
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.89%	1.96%
Underlying price inflation	2.44%	2.52%
U.K. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.59%	3.62%
U.K. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	4.09%	4.12%
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	3.23%	1.00%
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	5.19%	2.97%
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, 2022	Dec. 31, 2021	Dec. 31, 2020
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets, net of administration expenses	5.28%
U.S. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.67%	1.12%	2.36%
Expected return on plan assets, net of administration expenses	2.03%	2.65%	3.30%
U.S. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.25%	1.79%	2.76%
Expected return on plan assets, net of administration expenses	5.28%	6.56%	7.04%
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.85%	1.20%	1.89%
Expected return on plan assets, net of administration expenses	2.34%	2.04%	2.74%
U.K. | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.62%	3.22%	3.24%
U.K. | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	4.12%	3.72%	3.74%
Other | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	0.84%	0.28%	0.74%
Expected return on plan assets, net of administration expenses	1.80%	1.70%	2.10%
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	2.58%	2.00%	2.90%
Expected return on plan assets, net of administration expenses	3.15%	2.65%	3.10%
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, 2022
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	5.28%

XML

Employee Benefits - Schedule of Fair Value of U.S Plan Assets (Details) - Pension Plan - U.S. - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	$ 1,481	$ 2,378	$ 2,276
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	42	93
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	64	86
Equity derivatives
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	(6)	19
Equity investments, Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	293	548
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	192	249
Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	149	230
Fixed Income Investments, Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	507	838
Real estate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	113	156
Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	127	159
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	230	371
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	42	93
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	64	86
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	0
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	124	192
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	0
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	211	306
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	(6)	19
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	192	249
Significant Other Observable Inputs (Level 2) | Government and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets	25	38
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, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 3,537	$ 6,246	$ 6,652
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	1,929	3,841
Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(548)	(1,640)
Significant Unobservable Inputs (Level 3)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	1,403	2,305	$ 2,625
Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	336	872
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	336	872
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	0
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	(548)	(1,640)
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	(548)	(1,640)
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
Government and agency bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	1,593	2,969
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	1,593	2,969
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	1,403	2,305
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	1,403	2,305
Fixed Income Investments, Pooled Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	139	463
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	97	130
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	517	1,147
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	0
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, 2022	Dec. 31, 2021
Actual return on plan assets:
Balance at the beginning of the period	$ 6,246	$ 6,652
Foreign exchange	(559)	(76)
Balance at the end of the period	3,537	6,246
Significant Unobservable Inputs (Level 3)
Actual return on plan assets:
Balance at the beginning of the period	2,305	2,625
Relating to assets still held at the end of the year	(674)	(286)
Purchases, sales and settlements-net	0	0
Foreign exchange	(228)	(34)
Balance at the end of the period	$ 1,403	$ 2,305

XML

Employee Benefits - Schedule of Fair Value of Other Plan Assets (Details) - Pension Plan - Other - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	$ 1,032	$ 1,430	$ 1,497
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	308	451
Significant Other Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(3)	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	30	29
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	30	29
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	53	72
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	53	72
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	211	316
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	225	350
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	225	350
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
Derivatives
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	(3)
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
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	(3)
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
Fixed Income Investments, Pooled Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan assets	462	597
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	42	55
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	12	11
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, 2022
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	86.00%
Foreign Plan | Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual allocation percentage	8.00%
Pension Plan | U.S. | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation percentage	30.00%
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	16.00%

XML

Employee Benefits - Cash Flows Narrative (Details) - Pension Plan $ in Millions	Dec. 31, 2022 USD ($)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	$ 43
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	4
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions during next fiscal year	$ 14

XML

Employee Benefits - Estimated Future Benefit Payments (Details) - Pension Plan $ in Millions	Dec. 31, 2022 USD ($)
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2023	$ 157
2024	158
2025	158
2026	162
2027	155
2028 - 2032	754
U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2023	153
2024	157
2025	161
2026	166
2027	170
2028 - 2032	905
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2023	46
2024	47
2025	49
2026	50
2027	51
2028 - 2032	$ 274

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, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated projected benefit obligation	$ 83	$ 109
Fair value of plan assets	14	17
Funded status	(69)	(92)
Unrecognized prior-service credit	(1)	(1)
Unrecognized loss	(19)	2
Net amount recognized	$ (89)	$ (91)

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost recognized (millions)	$ 3	$ 5	$ 4
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted-average discount rate used to determine future benefit obligations	4.94%	2.52%	2.10%
Weighted-average discount rate used to determine net periodic benefit costs		1.45%	2.93%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted-average discount rate used to determine future benefit obligations	5.19%	3.06%	2.58%
Weighted-average discount rate used to determine net periodic benefit costs		2.68%	3.25%

XML

Employee Benefits - U.S. and Canadian Other Post-Retirement Benefits Narrative (Details) - Other Post-Retirement Benefits $ in Millions	Dec. 31, 2022 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected amortization of prior service credit, next fiscal year	$ 0.8
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 2023	5.0
Expected future benefit payments 2028 – 2032	$ 27.0

XML

Share-Based Compensation Plans - Share-based compensation expense recognized in continuing operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 397	$ 449	$ 312
Tax benefit	83	87	61
Share-based compensation expense, net of tax	314	362	251
Employee share purchase plans and other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	12	56	10
Restricted share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	251	204	186
Performance share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 134	$ 189	$ 116

XML

Share-Based Compensation Plans - Restricted Share Units Narrative (Details) - Restricted share units (RSUs) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share)	$ 279	$ 253	$ 185
Fair value of RSUs vested during the period	$ 216	$ 189	$ 190
Unamortized deferred compensation	$ 466
Weighted average remaining amortization period (in years)	2 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
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 and PSAs (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restricted share units
Non-vested share awards
Non-vested at beginning of period (in shares)	3,075
Granted (in shares)	1,117
Vested (in shares)	(1,154)
Forfeited (in shares)	(175)
Non-vested at end of period (in shares)	2,863	3,075
Fair Value at Date of Grant
Non-vested at beginning of period (in dollars per share)	$ 203
Granted (in dollars per share)	279	$ 253	$ 185
Vested (in dollars per share)	187
Forfeited (in dollars per share)	219
Non-vested at end of period (in dollars per share)	$ 238	$ 203
Performance-based Awards
Non-vested share awards
Non-vested at beginning of period (in shares)	1,298
Granted (in shares)	300
Vested (in shares)	(444)
Forfeited (in shares)	(18)
Non-vested at end of period (in shares)	1,136	1,298
Fair Value at Date of Grant
Non-vested at beginning of period (in dollars per share)	$ 181
Granted (in dollars per share)	311	$ 225	$ 163,000,000
Vested (in dollars per share)	163
Forfeited (in dollars per share)	217
Non-vested at end of period (in dollars per share)	$ 222	$ 181

XML

Share-Based Compensation Plans - Performance Share Awards Narrative (Details) - Performance-based Awards - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSA, vesting conditions period (in years)	3 years
Granted (in dollars per share)	$ 311	$ 225	$ 163,000,000
Shares issued (in shares)	888
Fair value of PSAs vested during the period	$ 145	$ 112	$ 121
Unamortized deferred compensation	$ 126
Weighted average remaining amortization period (in years)	1 year 3 months 18 days
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

Derivatives and Hedging - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months	$ 10
Gain (loss) on derivative	$ 4	$ (45)	$ (10)
Gross foreign exchange contracts | Not accounted for as hedges
Derivative [Line Items]
Derivative term of contract	90 days
Gain (loss) on derivative	$ (11)	$ 24	$ (1)
Gross foreign exchange contracts | Not accounted for as hedges | Maximum
Derivative [Line Items]
Derivative term of contract	1 year
Cash Flow Hedging
Derivative [Line Items]
Foreign currency exposures, maximum average hedging period (in years)	2 years

XML

Derivatives and Hedging - Notional and fair values of derivative instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Other Current Assets
Derivative [Line Items]
Derivative assets	$ 3	$ 21
Other Noncurrent Assets
Derivative [Line Items]
Derivative assets	9	8
Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	2
Other Noncurrent Liabilities
Derivative [Line Items]
Derivative liabilities	1
Accounted for as hedges | Gross foreign exchange contracts
Derivative [Line Items]
Derivative, Notional Amount	618	629
Derivative assets	12	27
Derivative liabilities	2	0
Not accounted for as hedges
Derivative [Line Items]
Derivative, Notional Amount	930	1,041
Derivative assets	12	29
Derivative liabilities	3	0
Not accounted for as hedges | Gross foreign exchange contracts
Derivative [Line Items]
Derivative, Notional Amount	312	412
Derivative assets	0	2
Derivative liabilities	$ 1	$ 0
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, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
(Loss) gain recognized in Accumulated other comprehensive loss	$ (15)	$ 0	$ 1
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	2	(2)	(15)
Total revenue
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	2	(3)	(14)
Compensation and benefits
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	0	1	0
Interest expense
Derivative [Line Items]
Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02	$ 0	$ 0	$ (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, 2022	Dec. 31, 2021
Money market funds
Assets
Money market funds	$ 3,323	$ 2,918
Government bonds
Assets
Other investments	1	1
Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	19	40
Liabilities
Gross foreign exchange contracts	9	11
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets
Money market funds	3,323	2,918
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) | 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) | Gross foreign exchange contracts
Assets
Gross foreign exchange contracts	19	40
Liabilities
Gross foreign exchange contracts	9	11
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) | 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, 2022	Dec. 31, 2021	Dec. 31, 2020
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, 2022	Dec. 31, 2021
Fair value of assets and liabilities [Line Items]
Long-term debt	$ 9,825	$ 8,228
Carrying Value
Fair value of assets and liabilities [Line Items]
Current portion of long-term debt	350	499
Long-term debt	9,825	8,228
Fair Value | Fair Value, Inputs, Level 2
Fair value of assets and liabilities [Line Items]
Current portion of long-term debt, fair value	347	507
Long term debt, fair value	$ 8,745	$ 9,204

XML

Claims, Lawsuits, and Other Contingencies - Legal Narrative (Details) £ in Millions, $ in Millions, $ in Millions			1 Months Ended
	Oct. 03, 2017 USD ($)	Oct. 03, 2017 NZD ($)	Dec. 31, 2022 plaintiff	Apr. 30, 2021 USD ($) plaintiff	Apr. 30, 2021 GBP (£) plaintiff	Aug. 31, 2020 USD ($) plaintiff	Nov. 30, 2019 USD ($) defendant	Nov. 30, 2018 USD ($)	Apr. 27, 2018 USD ($)
Pending Litigation | Aon Hewitt Investment Consulting, Inc.
Loss Contingencies [Line Items]
Investment losses suffered by plaintiff									$ 200.0
Pending Litigation | Fatal Plain Crash In November2016
Loss Contingencies [Line Items]
Value of damages sought				$ 35.0	£ 29	$ 844.0		$ 16.0
Loss contingency, number of defendants | defendant							3
Damages sought option 1							$ 300.0
Damages sought option 2							50.0
Damages sought option 3							$ 25.0
Loss contingency, number of plaintiffs | plaintiff			43	16	16	43
Settled Litigation | Christchurch City Council
Loss Contingencies [Line Items]
Value of damages sought	$ 202.0	$ 320

XML

Claims, Lawsuits, and Other Contingencies - Guarantees and Indemnifications Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Maximum potential funding under commitments	$ 173	$ 153

XML

Claims, Lawsuits, and Other Contingencies - Letters of Credit Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Letters of credit outstanding	$ 74	$ 75

XML

Claims, Lawsuits, and Other Contingencies - Premium Payments (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Maximum potential funding under commitments	$ 173	$ 153

XML

Segment Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 segment revenue_line performance_metric
Segment Reporting [Abstract]
Number of reportable segments | segment	1
Number of revenue lines | revenue_line	4
Number of performance metrics measured | performance_metric	4

XML

Segment Information - Schedule of consolidated non-current assets by geographic area (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	$ 1,300	$ 1,378
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	519	563
Americas other than U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	120	121
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	155	180
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	9	7
Other Europe, Middle East, & Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	279	293
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, including operating lease ROU assets	$ 218	$ 214