10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

     ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE QUARTERLY PERIOD ENDED MARCH 31, 2024

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 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 North America, Inc.’s 5.125% Senior Notes due 2027	AON27B	New York Stock Exchange
Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029	AON29	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 North America, Inc.’s 5.300% Senior Notes due 2031	AON31B	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 Corporation and Aon Global Holdings plc’s 5.35% Senior Notes due 2033	AON33	New York Stock Exchange
Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034	AON34	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
Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054	AON54	New York Stock Exchange

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 is a shell company (as defined in Rule 12b-2 of the Exchange Act).  Yes ☐ No ☒

Number of class A ordinary shares of Aon plc, $0.01 nominal value, outstanding as of April 25, 2024: 217,430,759

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, Section 27A of the Securities Act of 1933, as amended, (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Forward-looking statements represent management’s expectations or forecasts of future events. These statements include statements about our plans, objectives, strategies, financial performance and outlook, trends, prospects or other future events and involve known and unknown risks that are difficult to predict. 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, including the impacts of the Accelerating Aon United Program; 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 (including impacts from instability in the banking or commercial real estate sectors) 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 their respective parent entities;

•the impact of legal proceedings and other contingencies, including those arising from acquisition or disposition transactions, errors and omissions and other claims against us (including proceedings and contingencies relating to transactions for which capital was arranged by Vesttoo Ltd.);

•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 and the Israel-Hamas conflict;

•the effects of natural or man-made disasters, including the effects of health pandemics and the impacts of climate-related events;

•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 (including the Accelerating Aon United Program) and the ability to achieve such growth or cost savings;

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

•adverse effects on the market price of Aon’s securities and/or operating results for any reason, including, without limitation, because of a failure to realize the expected benefits of the acquisition of NFP (including anticipated revenue and growth synergies) in the expected timeframe, or at all;

•significant transaction and integration costs in connection with the acquisition of NFP or unknown or inestimable liabilities; and

•any potential adverse impact of the consummation of the acquisition of NFP on our relationships, including with suppliers, customers, employees, and regulators.

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 our Annual Report on Form 10-K for the year ended December 31, 2023. These factors may be revised or supplemented in our subsequent periodic filings with the SEC.

Table of Contents

PART I
	Item 1. Financial Statements
	Aon plc Condensed Consolidated Statements of Income
	Aon plc Condensed Consolidated Statements of Comprehensive Income
	Aon plc Condensed Consolidated Statements of Financial Position
	Aon plc Condensed Consolidated Statements of Shareholders’ Equity
	Aon plc Condensed Consolidated Statements of Cash Flows
	Notes to Condensed Consolidated Financial Statements
	Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations
	Item 3. Quantitative and Qualitative Disclosures about Market Risk
	Item 4. Controls and Procedures
PART II
	Item 1. Legal Proceedings
	Item 1A. Risk Factors
	Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
	Item 3. Defaults Upon Senior Securities
	Item 4. Mine Safety Disclosures
	Item 5. Other Information
	Item 6. Exhibits
	Signature
	Exhibit Index

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

Term	Definition
CODM	Chief Operating Decision Maker
DCF	Discounted Cash Flow
E&O	Errors and Omissions
EBITDA	Earnings Before Interest, Taxes, Depreciation, and Amortization
EMEA	Europe, the Middle East, and Africa
ERISA	Employee Retirement Income Security Act of 1974
ESG	Environmental, Social, and Governance
FCA	Financial Conduct Authority
GAAP	Generally Accepted Accounting Principles
GHG	Greenhouse Gas
LOC	Letter of Credit
M&A	Mergers and Acquisitions
OECD	Organisation for Economic Co-operation and Development
ROU	Right-of-Use
SEC	Securities and Exchange Commission
U.K.	United Kingdom
U.S.	United States

Part I Financial Information

Item 1. Financial Statements

Aon plc

Condensed Consolidated Statements of Income

(Unaudited)

	Three Months Ended March 31,
(millions, except per share data)	2024		2023
Revenue
Total revenue	$	4,070	$	3,871
Expenses
Compensation and benefits	1,883		1,792
Information technology	124		139
Premises	71		75
Depreciation of fixed assets	44		38
Amortization and impairment of intangible assets	16		25
Other general expense	348		329
Accelerating Aon United Program expenses	119		—
Total operating expenses	2,605		2,398
Operating income	1,465		1,473
Interest income	28		5
Interest expense	(144)		(111)
Other income (expense)	75		(25)
Income before income taxes	1,424		1,342
Income tax expense	331		263
Net income	1,093		1,079
Less: Net income attributable to noncontrolling interests	22		29
Net income attributable to Aon shareholders	$	1,071	$	1,050
Basic net income per share attributable to Aon shareholders	$	5.38	$	5.09
Diluted net income per share attributable to Aon shareholders	$	5.35	$	5.07
Weighted average ordinary shares outstanding - basic	199.1		206.1
Weighted average ordinary shares outstanding - diluted	200.1		207.1

See accompanying Notes to Condensed Consolidated Financial Statements (Unaudited).

6

Aon plc

Condensed Consolidated Statements of Comprehensive Income

(Unaudited) 

	Three Months Ended March 31,
(millions)	2024		2023
Net income	$	1,093	$	1,079
Less: Net income attributable to noncontrolling interests	22		29
Net income attributable to Aon shareholders	1,071		1,050
Other comprehensive income, net of tax:
Change in fair value of financial instruments	75		3
Foreign currency translation adjustments	(132)		54
Postretirement benefit obligation	26		22
Total other comprehensive income (loss)	(31)		79
Less: Other comprehensive income attributable to noncontrolling interests	—		—
Total other comprehensive income (loss) attributable to Aon shareholders	(31)		79
Comprehensive income attributable to Aon shareholders	$	1,040	$	1,129

See accompanying Notes to Condensed Consolidated Financial Statements (Unaudited).

7

Aon plc

Condensed Consolidated Statements of Financial Position

	(Unaudited)
(millions, except nominal value)	March 31, 2024		December 31, 2023
Assets
Current assets
Cash and cash equivalents	$	995	$	778
Short-term investments	5,413		369
Receivables, net	4,035		3,254
Fiduciary assets	17,161		16,307
Other current assets	1,020		996
Total current assets	28,624		21,704
Goodwill	8,302		8,414
Intangible assets, net	217		234
Fixed assets, net	590		638
Operating lease right-of-use assets	628		650
Deferred tax assets	1,254		1,195
Prepaid pension	627		618
Other non-current assets	525		506
Total assets	$	40,767	$	33,959
Liabilities and equity (deficit)
Liabilities
Current liabilities
Accounts payable and accrued liabilities	$	1,925	$	2,262
Short-term debt and current portion of long-term debt	606		1,204
Fiduciary liabilities	17,161		16,307
Other current liabilities	2,146		1,878
Total current liabilities	21,838		21,651
Long-term debt	15,916		9,995
Non-current operating lease liabilities	611		641
Deferred tax liabilities	129		115
Pension, other postretirement, and postemployment liabilities	1,198		1,225
Other non-current liabilities	1,103		1,074
Total liabilities	40,795		34,701
Equity (deficit)
Ordinary shares - $0.01 nominal value      Authorized: 500.0 shares (issued: 2024 - 198.6; 2023 - 198.6)	2		2
Additional paid-in capital	6,969		6,944
Accumulated deficit	(2,700)		(3,399)
Accumulated other comprehensive loss	(4,404)		(4,373)
Total Aon shareholders' deficit	(133)		(826)
Noncontrolling interests	105		84
Total deficit	(28)		(742)
Total liabilities and equity (deficit)	$	40,767	$	33,959

See accompanying Notes to Condensed Consolidated Financial Statements (Unaudited).

8

Aon plc

Condensed Consolidated Statements of Shareholders’ Equity (Deficit)

(Unaudited) 

(millions)	Shares	Ordinary Shares and Additional Paid-in Capital		Accumulated Deficit		Accumulated  Other Comprehensive Loss, Net of Tax		Non- controlling Interests		Total
Balance at January 1, 2024	198.6	$	6,946	$	(3,399)	$	(4,373)	$	84	$	(742)
Net income	—	—		1,071		—		22		1,093
Shares issued - employee stock compensation plans	0.8	(104)		—		—		—		(104)
Shares repurchased	(0.8)	—		(250)		—		—		(250)
Share-based compensation expense	—	130		—		—		—		130
Dividends to shareholders ($0.615 per share)	—	—		(122)		—		—		(122)
Net change in fair value of financial instruments	—	—		—		75		—		75
Net foreign currency translation adjustments	—	—		—		(132)		—		(132)
Net postretirement benefit obligation	—	—		—		26		—		26
Purchases of subsidiary shares from noncontrolling interests	—	(1)		—		—		—		(1)
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(1)		(1)
Balance at March 31, 2024	198.6	$	6,971	$	(2,700)	$	(4,404)	$	105	$	(28)

(millions)	Shares	Ordinary Shares and Additional Paid-in Capital		Accumulated Deficit		Accumulated  Other Comprehensive Loss, Net of Tax		Non- controlling Interests		Total
Balance at January 1, 2023	205.4	$	6,866	$	(2,772)	$	(4,623)	$	100	$	(429)
Net income	—	—		1,050		—		29		1,079
Shares issued - employee stock compensation plans	0.9	(131)		(1)		—		—		(132)
Shares repurchased	(1.8)	—		(550)		—		—		(550)
Share-based compensation expense	—	127		—		—		—		127
Dividends to shareholders ($0.56 per share)	—	—		(115)		—		—		(115)
Net change in fair value of financial instruments	—	—		—		3		—		3
Net foreign currency translation adjustments	—	—		—		54		—		54
Net postretirement benefit obligation	—	—		—		22		—		22
Dividends paid to noncontrolling interests on subsidiary common stock	—	—		—		—		(1)		(1)
Balance at March 31, 2023	204.5	$	6,862	$	(2,388)	$	(4,544)	$	128	$	58

See accompanying Notes to Condensed Consolidated Financial Statements (Unaudited).

9

Aon plc

Condensed Consolidated Statements of Cash Flows

(Unaudited)

	Three Months Ended March 31,
(millions)	2024		2023
Cash flows from operating activities
Net income	$	1,093	$	1,079
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation of fixed assets	44		38
Amortization and impairment of intangible assets	16		25
Share-based compensation expense	130		127
Deferred income taxes	(76)		(70)
Other, net	(82)		—
Change in assets and liabilities:
Receivables, net	(826)		(664)
Accounts payable and accrued liabilities	(343)		(443)
Accelerating Aon United Program liabilities	34		—
Current income taxes	163		126
Pension, other postretirement and postemployment liabilities	(12)		(9)
Other assets and liabilities	168		234
Cash provided by operating activities	309		443
Cash flows from investing activities
Proceeds from investments	118		13
Purchases of investments	(56)		(11)
Net sales (purchases) of short-term investments - non fiduciary	(5,046)		280
Acquisition of businesses, net of cash and funds held on behalf of clients	(4)		(2)
Sale of businesses, net of cash and funds held on behalf of clients	75		1
Capital expenditures	(48)		(76)
Cash provided by (used for) investing activities	(4,961)		205
Cash flows from financing activities
Share repurchase	(250)		(550)
Proceeds from issuance of shares	25		25
Cash paid for employee taxes on withholding shares	(130)		(157)
Commercial paper issuances, net of repayments	(591)		(173)
Issuance of debt	5,942		744
Increase in fiduciary liabilities, net of fiduciary receivables	394		636
Cash dividends to shareholders	(123)		(115)
Noncontrolling interests and other financing activities	(6)		(6)
Cash provided by financing activities	5,261		404
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(146)		58
Net increase in cash and cash equivalents and funds held on behalf of clients	463		1,110
Cash, cash equivalents and funds held on behalf of clients at beginning of period	7,722		7,076
Cash, cash equivalents and funds held on behalf of clients at end of period	$	8,185	$	8,186
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	$	995	$	1,119
Cash and cash equivalents and funds held on behalf of clients classified as held for sale	73		—
Funds held on behalf of clients	7,117		7,067
Total cash and cash equivalents and funds held on behalf of clients	$	8,185	$	8,186
Supplemental disclosures:
Interest paid	$	95	$	79
Income taxes paid, net of refunds	$	244	$	206

See accompanying Notes to Condensed Consolidated Financial Statements (Unaudited).

10

Notes to Condensed Consolidated Financial Statements (Unaudited)

1. Basis of Presentation

The accompanying Condensed Consolidated Financial Statements and Notes thereto have been prepared in accordance with U.S. GAAP. The Condensed 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 Condensed 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.

Certain information and disclosures normally included in the Consolidated Financial Statements prepared in accordance with U.S. GAAP have been condensed or omitted. The Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of operating results that may be expected for the full year ending December 31, 2024.

Use of Estimates

The preparation of the accompanying Condensed 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 Condensed 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 Condensed Consolidated Financial Statements in future periods.

2. Accounting Principles and Practices

New Accounting Pronouncements

Accounting Standards Issued But Not Yet Adopted

Improvements to Reportable Segment Disclosures

In November 2023, the FASB issued new accounting guidance, requiring new segment disclosures under ASC 280, Segment Reporting, including disclosure of significant segment expense categories and amounts that are regularly reported to the CODM and included in the segment’s profit or loss. Additionally, all disclosure requirements under ASC 280, including new requirements under this new guidance, will be required on an interim basis. The new guidance is effective for Aon for the year ended December 31, 2024 and interim periods thereafter, with early adoption permitted. An entity will apply the new guidance on a retrospective basis for all periods presented. The Company is currently evaluating the impact the guidance will have on the Notes to Consolidated Financial Statements.

Improvements to Income Tax Disclosures

In December 2023, the FASB issued new accounting guidance under ASC 740, Income Taxes, which requires additional income tax disclosures on an annual basis, including disaggregation of information presented within the reconciliation of the expected tax to the reported tax by specific categories, with certain reconciling items 5% or greater broken out by nature and/or jurisdiction. The new guidance also requires disclosure of income taxes paid, net of refunds, broken out by federal, state/local, and foreign, including disclosure of individual jurisdictions when greater than 5% of total net income taxes paid. The new guidance is effective for Aon for the year ended December 31, 2025, with early adoption permitted. The Company is evaluating the period of adoption and transition approach, as well as the impact the disclosures will have on the Notes to Consolidated Financial Statements.

11

Securities and Exchange Commission Final Rules

The Enhancement and Standardization of Climate-Related Disclosures for Investors

In March 2024, the SEC adopted final rules to enhance and standardize climate-related disclosures. The final rules will require the Company to provide certain climate-related information in Item 7, Management’s Discussion and Analysis regarding material climate-related risks, activities to mitigate or adapt to such risks, information regarding oversight and management of climate-related risks, information on climate-related targets or goals, and disclosure of Scope 1 and 2 greenhouse gas (“GHG”) emissions. Additionally, within the Notes to Consolidated Financial Statements, the Company will be required to disclose the financial statement effects of severe weather events and other natural conditions. The final rules are effective for Aon for the year-ended December 31, 2025, with the exception of GHG emissions disclosures which are effective for Aon for the year-ended December 31, 2026. After the adoption of the final rules, the final rules became subject to several legal challenges, and on April 4, 2024 the SEC voluntarily stayed the final rules pending judicial review. The Company is currently evaluating the impact that the guidance will have on our disclosures and will monitor the judicial process for impacts on the disclosure requirements.

3. Revenue from Contracts with Customers

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions):

	Three Months Ended March 31,
	2024		2023
Commercial Risk Solutions	$	1,808	$	1,778
Reinsurance Solutions	1,167		1,077
Health Solutions	733		671
Wealth Solutions	370		350
Eliminations	(8)		(5)
Total revenue	$	4,070	$	3,871

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):

	Three Months Ended March 31,
	2024		2023
United States	$	1,512	$	1,495
Americas other than United States	323		301
United Kingdom	583		554
Ireland	33		30
Europe, Middle East, & Africa other than United Kingdom and Ireland	1,209		1,102
Asia Pacific	410		389
Total revenue	$	4,070	$	3,871

12

Contract Costs

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	370	$	355
Additions	380		362
Amortization	(478)		(462)
Impairment	—		—
Foreign currency translation and other	(3)		2
Balance at end of period	$	269	$	257

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	195	$	185
Additions	14		10
Amortization	(13)		(12)
Impairment	—		—
Foreign currency translation and other	(2)		—
Balance at end of period	$	194	$	183

4. Accelerating Aon United Program

In the third quarter of 2023, Aon initiated a three-year restructuring program called the Accelerating Aon United Program (the “Program”) with the purpose of streamlining the Company’s technology infrastructure, optimizing its leadership structure and resource alignment, and reducing the real estate footprint to align to its hybrid working strategy. The Program will include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation and technology costs.

Program charges are recognized within Accelerating Aon United Program expenses on the accompanying Condensed Consolidated Statements of Income and consists of the following cost activities:

•Technology and other – includes costs associated with actions taken to rationalize certain applications and to optimize technology across the Company. These costs may include contract termination fees and other non-capitalizable costs associated with Program initiatives, which include professional service fees.

•Workforce optimization – includes costs associated with headcount reduction and other separation-related costs.

•Asset impairments – includes non-cash costs associated with impairment of assets, as they are identified, including ROU lease assets, leasehold improvements, and other capitalized assets no longer providing economic benefit.

The Program is currently expected to result in cumulative costs of approximately $1.0 billion, consisting of approximately $900 million of cash charges and approximately $100 million of non-cash charges. For the three months ended March 31, 2024, total Program costs incurred were $119 million. The Company expects to continue to review the implementation of elements of the Program throughout the course of the Program and, therefore, there may be changes to expected timing, estimates of expected costs, and related savings.

The Company’s unpaid liabilities for charges under the Program are generally included in Accounts payable and accrued liabilities in the Condensed Consolidated Statements of Financial Position.

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The changes in the Company’s liabilities for the Program as of March 31, 2024 are as follows (in millions):

	Technology and other		Workforce optimization		Asset impairments		Total
Liability Balance as of January 1, 2024	$	14	$	86	$	—	$	100
Charges	19		64		36		119
Cash payments	(12)		(25)		—		(37)
Foreign currency translation and other	—		(1)		—		(1)
Non-cash charges	(7)		(5)		(36)		(48)
Liability balance as of March 31, 2024	$	14	$	119	$	—	$	133
Total costs incurred from inception to date	$	33	$	167	$	54	$	254

5. Cash and Cash Equivalents and Short-Term Investments

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

At March 31, 2024, Cash and cash equivalents and Short-term investments were $6.4 billion compared to $1.1 billion at December 31, 2023, an increase of $5.3 billion primarily related to net proceeds from debt offerings to be used for general corporate purposes, including to fund the acquisition of NFP. Refer to Note 9 “Debt” for further information. Of the total balances, $112 million and $120 million were restricted as to their use at March 31, 2024 and December 31, 2023, respectively. Included within Short-term investments as of March 31, 2024 and December 31, 2023, were £55 million ($70 million at March 31, 2024 exchange rates) and £63 million ($80 million at December 31, 2023 exchange rates), respectively, of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator.

6. Other Financial Data

Condensed Consolidated Statements of Income Information

Other Income (Expense)

Other income (expense) consists of the following (in millions):

	Three Months Ended March 31,
	2024		2023
Foreign currency remeasurement	4		(19)
Equity earnings	2		3
Pension and other postretirement	(10)		(17)
Financial instruments and other (1)	79		8
Total	$	75	$	(25)

(1)For the period ended March 31, 2024, an $82 million gain was recognized related to deferred consideration from the affiliates of The Blackstone Group L.P and the other designated purchasers related to a divestiture completed in a prior year period, refer to Note 7, “Acquisitions and Dispositions of Businesses” for additional information.

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Condensed 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):

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	79	$	76
Provision	5		7
Accounts written off, net of recoveries	(2)		—
Foreign currency translation and other	(1)		—
Balance at end of period	$	81	$	83

Other Current Assets

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

As of	March 31, 2024		December 31, 2023
Assets held for sale (1)	$	446	$	354
Costs to fulfill contracts with customers (2)	269		370
Prepaid expenses	128		100
Taxes receivable	19		35
Other	158		137
Total	$	1,020	$	996

(1)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

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

Other Non-Current Assets

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

As of	March 31, 2024		December 31, 2023
Costs to obtain contracts with customers (1)	$	194	$	195
Taxes receivable	98		100
Investments	80		45
Leases	21		26
Other	132		140
Total	$	525	$	506

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

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Other Current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable	$	397	$	291
Deferred revenue (1)	360		270
Leases	179		182
Liabilities held for sale (2)	129		69
Other	1,081		1,066
Total	$	2,146	$	1,878

(1)During the three months ended March 31, 2024, revenue of $179 million was recognized in the Condensed Consolidated Statements of Income. During the three months ended March 31, 2023, revenue of $167 million was recognized in the Condensed Consolidated Statements of Income.

(2)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

Other Non-Current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable (1)	$	866	$	827
Compensation and benefits	55		59
Deferred revenue	31		33
Leases	5		10
Other	146		145
Total	$	1,103	$	1,074

(1)Includes $72 million for the non-current portion of the one-time mandatory transition tax on accumulated foreign earnings as of March 31, 2024 and December 31, 2023.

7. Acquisitions and Dispositions of Businesses

Completed Acquisitions

The Company completed no acquisitions during the three months ended March 31, 2024 and no acquisitions during the three months ended March 31, 2023.

2023 Acquisitions

On November 30, 2023, the Company completed the acquisition of 100% of the share capital of Gi&Bi S.r.l., an Italy-based insurance broker specialized in the agricultural business segment.

On August 30, 2023, the Company completed the acquisition of 100% of the share capital of NGS (Uruguay) S.A., a risk management consultant firm in Uruguay.

On June 22, 2023, the Company completed the acquisition of 100% of the share capital of Benefits Corredores de Seguros and Asesorías e Inversiones Benefits, a business that provides health and benefits brokerage and benefit administration in Chile.

Completed Dispositions

The Company completed one disposition during the three months ended March 31, 2024 and no dispositions during the three months ended March 31, 2023.

There were no pretax gains recognized related to dispositions for the three months ended March 31, 2024 or 2023, respectively. Gains recognized as a result of a disposition are included in Other income (expense) in the Condensed Consolidated Statements of Income. There were no losses recognized for the three months ended March 31, 2024 or 2023, respectively.

Assets and Liabilities Held for Sale

As of March 31, 2024, Aon classified certain assets and liabilities as held for sale, as the Company has committed to a plan to sell the assets and liabilities within one year. Total assets and liabilities, for disposal groups classified as held for sale within

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Other current assets and Other current liabilities in the Condensed Consolidated Statements of Financial Position were $446 million and $129 million, respectively. Of the $446 million total assets classified as held for sale, $156 million relate to intangible assets.

Other Significant Activity

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”) and certain designated purchases that are direct or indirect subsidiaries of the Buyer. The Buyer purchased all of the outstanding equity interests of the Divested Business, plus certain related assets and liabilities for a purchase price of $4.3 billion in cash paid at closing and deferred consideration of up to $500 million. In the first quarter of 2024, the Company earned $82 million of deferred consideration from the Buyer and the other designated purchasers.

8. Goodwill and Other Intangible Assets

The changes in the net carrying amount of goodwill for the three months ended March 31, 2024 are as follows (in millions):

Balance as of December 31, 2023	$	8,414
Foreign currency translation and other	(112)
Balance as of March 31, 2024	$	8,302

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

	March 31, 2024						December 31, 2023
	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	$	1,857	$	1,683	$	174	$	1,873	$	1,686	$	187
Technology and other	367		324		43		371		324		47
Total	$	2,224	$	2,007	$	217	$	2,244	$	2,010	$	234

The estimated future amortization for finite-lived intangible assets as of March 31, 2024 is as follows (in millions):

Remainder of 2024	$	52
2025	55
2026	34
2027	22
2028	17
2029	12
Thereafter	25
Total	$	217

9. Debt

Notes

On March 1, 2024, Aon North America, Inc. issued $600 million 5.125% Senior Notes due in March 2027, $1 billion 5.150% Senior Notes due in March 2029, $650 million 5.300% Senior Notes due in March 2031, $1.75 billion 5.450% Senior Notes due in March 2034, and $2 billion 5.750% Senior Notes due in March 2054, totaling to an aggregate amount of $6 billion. The Company intends to use the net proceeds from the offering for general corporate purposes, including a portion of which that was used, together with the proceeds of the delayed draw term loan available under the credit agreement entered into on February 16, 2024 described below, to pay a portion of the cash consideration in connection with the acquisition of NFP, to repay certain debt of NFP and to pay related fees and expenses.

On February 16, 2024, Aon North America, Inc. entered into a credit agreement in which lenders committed to provide a $2 billion delayed draw term loan, which was subsequently drawn on April 25, 2024. The Company intends to use proceeds, together with the proceeds of the notes issued on March 1, 2024 described above, to pay a portion of the cash consideration in connection with the NFP acquisition, to repay certain debt of NFP and to pay related fees and expenses.

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In November 2023, Aon Global Limited’s $350 million 4.00% Senior Notes matured and were repaid in full.

In June 2023, Aon Global Limited’s $600 million 3.50% Senior Notes due June 2024 were classified as Short-term debt and current portion of long-term debt in the Condensed Consolidated Statement of Financial Position as the date of maturity is in less than one year.

On February 28, 2023, 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 $750 million 5.35% Senior Notes due in February 2033. The Company intends to use the net proceeds from the offering for general corporate purposes.

Revolving Credit Facilities

As of March 31, 2024, Aon had two primary committed credit facilities outstanding: its $1.0 billion multi-currency U.S. credit facility expiring in September 2027 and its $1.0 billion multi-currency U.S. credit facility expiring in October 2028. In aggregate, these two facilities provide $2.0 billion in available credit.

Each of these primary committed credit facilities and the delayed draw term loan 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. Aon did not have borrowings under either of these primary committed credit facilities nor the delayed draw term loan as of March 31, 2024 and December 31, 2023, respectively. Additionally, Aon was in compliance with the financial covenants and all other covenants contained therein during the rolling 12 months ended March 31, 2024.

Commercial Paper

Aon Corporation has established a U.S. commercial paper program (the “U.S. Program”) and Aon Global Holdings plc has established a European multi-currency commercial paper program (the “European Program” and, together with the U.S. Program, the “Commercial Paper Program”). Commercial paper may be issued in aggregate principal amounts of up to approximately $1.3 billion under the U.S. Program and €625 million ($677 million at March 31, 2024 exchange rates) under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was $2.0 billion at March 31, 2024. 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, Aon North America, Inc., and Aon Global Holdings plc and the European Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, Aon North America, Inc., and Aon Corporation.

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

	March 31, 2024		December 31, 2023
Commercial paper outstanding	$	—	$	597

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

	Three Months Ended March 31,
	2024			2023
Weighted average commercial paper outstanding	$	381		$	393
Weighted average interest rate of commercial paper outstanding	5.65		%	3.38		%

10. Income Taxes

The effective tax rate on Net income was 23.2% for the three months ended March 31, 2024. The effective tax rate on Net income was 19.6% for the three months ended March 31, 2023.

For the three months ended March 31, 2024, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, including the favorable impact of share-based payments offset by the unfavorable impact of discrete items.

For the three months ended March 31, 2023, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, primarily the favorable impacts of share-based payments.

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11. Shareholders’ Equity (Deficit)

Ordinary Shares

Aon has a share repurchase program authorized by the Company’s Board of Directors (“the Repurchase Program”). 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):

	Three Months Ended March 31,
	2024		2023
Shares repurchased	0.8		1.8
Average price per share	$	310.56	$	305.31
Repurchase costs recorded to accumulated deficit	$	250	$	550

At March 31, 2024, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $3.1 billion. Under the Repurchase Program, the Company has repurchased a total of 169.9 million shares for an aggregate cost of approximately $24.4 billion.

Weighted Average Ordinary Shares

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

	Three Months Ended March 31,
	2024	2023
Basic weighted average ordinary shares outstanding	199.1	206.1
Dilutive effect of potentially issuable shares	1.0	1.0
Diluted weighted average ordinary shares outstanding	200.1	207.1

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 0.1 million shares excluded from the calculation for the three months ended March 31, 2024 and no shares excluded from the calculation for the three months ended March 31, 2023.

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, 2023	$	2	$	(1,584)	$	(2,791)	$	(4,373)
Other comprehensive income (loss) before reclassifications, net	72		(132)		—		(60)
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	4		—		35		39
Tax expense	(1)		—		(9)		(10)
Amounts reclassified from accumulated other comprehensive income, net	3		—		26		29
Net current period other comprehensive income (loss)	75		(132)		26		(31)
Balance at March 31, 2024	$	77	$	(1,716)	$	(2,765)	$	(4,404)

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	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)
Other comprehensive income (loss) before reclassifications, net	—		54		(1)		53
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	5		—		32		37
Tax expense	(2)		—		(9)		(11)
Amounts reclassified from accumulated other comprehensive income, net	3		—		23		26
Net current period other comprehensive income (loss)	3		54		22		79
Balance at March 31, 2023	$	(8)	$	(1,807)	$	(2,729)	$	(4,544)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Condensed 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 Condensed Consolidated Statements of Income.

12. Employee Benefits

The following table provides the components of the net periodic (benefit) cost recognized in the Condensed Consolidated Statements of Income for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	Three Months Ended March 31,
	U.K.				U.S.				Other
	2024		2023		2024		2023		2024		2023
Service cost	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	35		36		23		26		9		10
Expected return on plan assets, net of administration expenses	(47)		(46)		(33)		(30)		(13)		(12)
Amortization of prior-service cost	1		—		—		—		—		—
Amortization of net actuarial loss	20		18		7		9		3		3
Net periodic (benefit) cost	9		8		(3)		5		(1)		1
Loss on pension settlement	—		—		—		—		—		—
Total net periodic (benefit) cost	$	9	$	8	$	(3)	$	5	$	(1)	$	1

Contributions

Assuming no additional contributions are agreed to with, or required by, the pension plan trustees, the Company expects to make total cash contributions of approximately $2 million, $53 million, and $13 million (at December 31, 2023 exchange rates) to its significant U.K., U.S., and other major pension plans, respectively, during 2024. The following table summarizes contributions made to the Company’s significant pension plans (in millions):

	Three Months Ended March 31,
	2024		2023
Contributions to U.K. pension plans	$	1	$	1
Contributions to U.S. pension plans	14		16
Contributions to other major pension plans	2		6
Total contributions	$	17	$	23

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13. Derivatives and Hedging

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

Foreign Exchange Risk Management

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

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

	Notional Amount				Net Amount of Derivative Assets  Presented in the Statements of Financial Position (1)				Net Amount of Derivative Liabilities  Presented in the Statements of Financial Position (2)
	March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023
Foreign exchange contracts
Accounted for as hedges	$	736	$	1,724	$	36	$	34	$	—	$	2
Not accounted for as hedges (3)	459		382		1		2		—		1
Total	$	1,195	$	2,106	$	37	$	36	$	—	$	3

(1)Included within Other current assets ($19 million at March 31, 2024 and $17 million at December 31, 2023) or Other non-current assets ($18 million at March 31, 2024 and $19 million at December 31, 2023).

(2)Included within Other current liabilities ($3 million at December 31, 2023).

(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 recognized in the Condensed Consolidated Financial Statements are as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Gain recognized in Accumulated other comprehensive loss	$	97	$	—

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

	Three Months Ended March 31,
	2024		2023
Losses recognized in Total revenue	$	(4)	$	(5)

The Company estimates that approximately $2 million of pretax gains currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

During the three months ended March 31, 2024 and March 31, 2023, the Company recorded a loss of $3 million and gain of $9 million, respectively, 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:

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.

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 Condensed 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.

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 March 31, 2024 and December 31, 2023 (in millions):

			Fair Value Measurements Using
	Balance at March 31, 2024		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)	$	8,236	$	8,236	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	58	$	—	$	58	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	22	$	—	$	22	$	—

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			Fair Value Measurements Using
	Balance at December 31, 2023		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)	$	3,204	$	3,204	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	49	$	—	$	49	$	—
Liabilities					0
Derivatives (2)
Gross foreign exchange contracts	$	16	$	—	$	16	$	—

(1)Included within Fiduciary assets or Short-term investments in the Condensed 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 in the three months ended March 31, 2024 or 2023. The Company recognized no realized or unrealized gains or losses in the Condensed Consolidated Statements of Income during the three months ended March 31, 2024 or 2023 related to assets and liabilities measured at fair value using unobservable inputs.

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):

	March 31, 2024				December 31, 2023
	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	600	$	598	$	600	$	595
Long-term debt	$	15,916	$	15,151	$	9,995	$	9,223

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, including coverage from Aon’s self-insurance program. Accruals for these exposures, and related insurance receivables, when applicable, are included in the Condensed Consolidated Statements of Financial Position and have been recognized in Other general expense in the Condensed 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’s contingencies and exposures are subject to significant uncertainties, and the determination of likelihood of a loss and estimating any such loss can be complex. The Company is therefore, in certain matters, unable to estimate the range of reasonably possible loss. 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. Certain significant legal proceedings involving us or our subsidiaries are described below.

Current Matters

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

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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 ($37 million at March 31, 2024 exchange rates). In February 2024, the claim brought by representatives of 16 passengers in the High Court in England was dismissed pursuant to an agreement among the parties. 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.

Certain of the Company’s clients and counterparties have initiated or indicated that they may initiate legal proceedings against the Company following allegations in July 2023 that fraudulent letters of credit were issued in the name of third-party banks in connection with transactions for which capital was arranged by Vesttoo Ltd. (“Vesttoo”). Vesttoo is one of the third parties that identifies capital providers to collateralize insurance and reinsurance obligations of the Company’s clients and counterparties. In certain transactions in which Vesttoo identified third party capital providers to collateralize reinsurance obligations, including transactions in which the Company or its affiliates provided brokerage or other services, some letters of credit from third party banks are alleged to have been fraudulent. The pending or threatened legal proceedings against the Company allege, among other theories of liability, that in certain circumstances the Company failed to comply with its alleged duty to procure appropriate letters of credit. In particular, on November 30, 2023, Clear Blue Insurance Company and certain of its affiliates filed a lawsuit in New York State Supreme Court against Aon plc and Aon Insurance Managers (Bermuda) Ltd. alleging such claims. While Aon has settled and/or is in discussions to settle certain claims, Aon believes that it has meritorious defenses and intends to vigorously defend itself against those claims that are not settled. In the fourth quarter of 2023, the Company recognized actual or anticipated legal settlement expenses in connection with these matters of $197 million, of which a potentially significant amount may be recoverable in future periods. Aon may also seek recourse against third parties where appropriate, including in connection with bankruptcy proceedings filed by Vesttoo in the Bankruptcy Court for the U.S. District of Delaware. In addition, in August 2023, joint provisional liquidators were appointed over one of the Company’s subsidiaries in Bermuda with respect to segregated accounts that were impacted by the allegedly fraudulent letters of credit. Aon continues to cooperate with regulators in Bermuda, and other regulatory authorities could initiate investigations or proceedings against the Company or third parties.

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 Condensed Consolidated 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

On June 22, 2023, Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon Corporation, and Aon North America, Inc., and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”), as applicable, entered into supplemental indentures, each dated June 22, 2023, amending each of the following indentures (as amended, supplemented or modified from time to time) to add for the benefit of the holders of the instruments issued thereunder a full and unconditional guarantee of Aon North America, Inc. thereunder: (i) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the Indenture, dated January 13, 1997); (ii) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the

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Indenture, dated September 10, 2010); (iii) Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 12, 2012); (iv) Second Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated May 20, 2015, amending and restating the Indenture, dated May 24, 2013); (v) Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated November 13, 2015); and (vi) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 3, 2018).

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 $139 million at March 31, 2024, and $86 million at December 31, 2023. These LOCs cover the beneficiaries related to certain of Aon’s U.S. and Canadian secure non-qualified pension plan schemes, reinsurance obligations related to Aon’s own E&O liability insurance program, 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 $110 million at March 31, 2024 compared to $194 million at December 31, 2023.

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 and Human Capital Solutions through four solution lines — Commercial risk, Reinsurance, Health, and Wealth, 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 Condensed Consolidated Statements of Income. Refer to Note 3 “Revenue from Contracts with Customers” for further information on revenue by principal service line.

17.    Subsequent Events

NFP Acquisition

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp. in a cash-and-stock merger for an aggregate preliminary purchase price totaling $9.1 billion, with approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion. The initial accounting for the acquisition is incomplete as of the date of this Form 10-Q, as the information necessary to complete such evaluations was not practicable due to the timing of acquisition closing. We have not yet determined the purchase price allocation, including the fair value of the acquisition. The preliminary accounting impact of this acquisition will be included in our Condensed Consolidated Financial Statements beginning in the second quarter of 2024.

Debt Activity

On April 2, 2024, Aon plc announced that its wholly owned subsidiary, Randolph Acquisition Corp., commenced cash tender offers for any and all of the outstanding 6.875% Senior Notes due 2028, 4.875% Senior Secured Notes due 2028, 7.500% Senior Secured Notes due 2030 and 8.500% Senior Secured Notes due 2031, each issued by NFP Corp. (together, the “NFP Notes”), upon the terms and subject to the conditions set forth in the Offer to Purchase and Consent Solicitation Statement,

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dated as of April 2, 2024. On April 26, 2024, the Offeror purchased those NFP Notes that were validly tendered and not validly withdrawn prior to April 15, 2024, effecting the early settlement of the Offers (the “Early Settlement”). In addition, on April 16, 2024, NFP Corp. delivered notices of redemption of all NFP Notes not validly tendered pursuant to the Offers and purchased at the Early Settlement, at a purchase price equal to the price paid to holders of the NFP Notes in connection with the Early Settlement, with a redemption date of April 26, 2024. As a result of the Early Settlement of the Offers and the related redemption which occurred on April 26, 2024, no NFP Notes remain outstanding.

Disposition of Business

On April 20, 2024, Aon signed a definitive agreement to sell Healthy Paws, its U.S.-based managing general agent specializing in pet insurance, to Chubb Limited. Assets and liabilities associated with this disposal group were classified as held for sale as of March 31, 2024. The disposition is expected to be completed in the second quarter of 2024.

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Item 2.  Management’s Discussion and Analysis of Financial Condition and Results of Operations

EXECUTIVE SUMMARY OF FIRST QUARTER 2024 FINANCIAL RESULTS

Aon plc is a leading global professional services firm providing a broad range of Risk and Human Capital Solutions. Through our experience, global reach, and comprehensive analytics, we help clients meet rapidly changing, increasingly complex, and interconnected challenges related to risk and people. 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 remains 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 first quarter of 2024 financial results.

•Revenue increased $199 million, or 5%, to $4.1 billion compared to the prior year period reflecting organic revenue growth of 5%, a 1% favorable impact from fiduciary investment income and a 1% favorable impact from foreign currency translation, partially offset by a 2% unfavorable impact from acquisitions, divestitures and other items.

•Total operating expenses in the first quarter increased $207 million, or 9%, to $2.6 billion compared to the prior year period due primarily to Accelerating Aon United restructuring charges, an increase in expense associated with 5% organic revenue growth, investments in long-term growth, and a $22 million unfavorable impact from foreign currency translation, partially offset by $20 million of restructuring savings realized in the quarter.

•Operating margin decreased to 36.0% from 38.1% in the prior year period. The decrease was driven by an increase in operating expenses as listed above, partially offset by organic revenue growth of 5%.

•Due to the factors set forth above, net income increased $14 million, or 1%, to $1.1 billion compared to the prior year period.

•Diluted earnings per share was $5.35 compared to $5.07 per share for the prior year period.

•Cash flows provided by operating activities was $309 million for the first three months of 2024, a decrease of $134 million from the prior year period, primarily due to higher receivables, payments related to E&O, restructuring, higher cash taxes and transaction and integration costs, partially offset by strong operating income growth.

We focus on four key metrics not presented in accordance with U.S. GAAP that we communicate to shareholders: organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, and free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our Condensed Consolidated Financial Statements. The following is our measure of performance against these four metrics for the first quarter of 2024:

•Organic revenue growth is a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth.” Organic revenue growth was 5% for the first quarter of 2024, driven by ongoing strong retention, net new business generation, and management of the renewal book.

•Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was 39.7% for the first quarter of 2024 compared to 38.7% in the prior year period. The increase in adjusted operating income reflects organic revenue growth, increased fiduciary investment income, and $20 million of restructuring savings realized in the quarter, 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 $5.66 per share for the first quarter of 2024, compared to $5.17 per share for the respective prior year period.

•Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” decreased in the first three months of 2024 by $106 million from the prior year period, to $261 million, reflecting a decrease in cash flows from operations, partially offset by a $28 million decrease in capital expenditures.

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 various work environments, continue to create volatility and uncertainty for our clients. At Aon, helping clients manage risk - including ESG risk - is at the core of what we do. We offer a wide range of risk assessment, consulting, and advisory solutions, many of which are significant parts of our core business

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offerings, designed to address and manage ESG issues for clients, and to enable our clients to create more sustainable value. We see significant opportunity in enhancing our impact and delivering innovative client solutions on ESG matters.

ACQUISITION OF NFP

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp. in a cash-and-stock merger for an aggregate preliminary purchase price totaling $9.1 billion, with approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion.

REVIEW OF CONSOLIDATED RESULTS 

Summary of Results

Our consolidated results (unaudited) are as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Revenue
Total revenue	$	4,070	$	3,871
Expenses
Compensation and benefits	1,883		1,792
Information technology	124		139
Premises	71		75
Depreciation of fixed assets	44		38
Amortization and impairment of intangible assets	16		25
Other general expense	348		329
Accelerating Aon United Program expenses	119		—
Total operating expenses	2,605		2,398
Operating income	1,465		1,473
Interest income	28		5
Interest expense	(144)		(111)
Other income (expense)	75		(25)
Income before income taxes	1,424		1,342
Income tax expense	331		263
Net income	1,093		1,079
Less: Net income attributable to noncontrolling interests	22		29
Net income attributable to Aon shareholders	$	1,071	$	1,050
Diluted net income per share attributable to Aon shareholders	$	5.35	$	5.07
Weighted average ordinary shares outstanding - diluted	200.1		207.1

Revenue

Total revenue increased $199 million, or 5%, to $4.1 billion, compared to the prior year period, with organic revenue growth of 5%, driven by ongoing strong retention, net new business generation, and management of the renewal book, a 1% favorable impact from fiduciary investment income and a 1% favorable impact from foreign currency translation partially offset by a 2% unfavorable impact from acquisitions, divestitures and other items.

Commercial Risk Solutions revenue increased $30 million, or 2%, to $1.8 billion in the first quarter of 2024, compared to the first quarter of 2023. Organic revenue growth was 3% in the first quarter of 2024, reflecting growth across most major geographies driven by strong retention, management of the renewal book, and net new business generation. Growth in retail brokerage was highlighted by solid growth in EMEA and Asia and the Pacific, driven by continued strength in core P&C. Results in the U.S. were pressured, reflecting lower net new business and the ongoing impacts from external capital markets activity. Results also reflect growth in Affinity globally across both consumer and benefits solutions. On average globally, exposures and pricing were positive, resulting in modestly positive market impact.

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Reinsurance Solutions revenue increased $90 million, or 8%, to $1.2 billion in the first quarter of 2024, compared to $1.1 billion in the first quarter of 2023. Organic revenue growth was 7% in the first quarter of 2024, reflecting strong growth in treaty, driven by strong retention and new business generation, as well as double-digit growth in the Strategy and Technology Group. Market impact was modestly positive on results in the quarter. The majority of revenue in our treaty portfolio is recurring in nature and is recorded in connection with the major renewal periods that take place throughout the first half of the year, while the second half of the year is typically driven by facultative placements, capital markets activity and advisory work that is more transactional in nature.

Health Solutions revenue increased $62 million, or 9%, to $733 million in the first quarter of 2024, compared to $671 million in the first quarter of 2023. Organic revenue growth was 6% in the first quarter of 2024, reflecting strong growth globally in core health and benefits brokerage driven by new business generation and management of the renewal book. Strength in the core was highlighted by solid growth in all major geographies. Results also reflect strong growth in Consumer Benefit Solutions, partially offset by a decline in Talent driven by lower project-related revenue in advisory solutions.

Wealth Solutions revenue increased $20 million, or 6%, to $370 million in the first quarter of 2024, compared to $350 million in the first quarter of 2023. Organic revenue growth was 4% in the first quarter of 2024, reflecting strong growth in Retirement, driven by advisory demand and project-related work related to pension de-risking and ongoing impact of regulatory changes. Investments declined modestly as strong advisory demand in North America was more than offset by a decline in project-related work in the U.K.

Compensation and Benefits

Compensation and benefits expense increased $91 million, or 5%, compared to the prior year period due primarily to an increase in expense associated with 5% organic revenue growth, and an $18 million unfavorable impact from foreign currency translation, partially offset by savings from Accelerating Aon United restructuring actions.

Information Technology

Information technology expenses, which represent costs associated with supporting and maintaining our infrastructure, decreased $15 million, or 11%, compared to the prior year period due primarily to elevated technology costs and investments in the prior year period, noting that spend may vary between quarters given timing of projects and investments within the year.

Premises

Premises expenses, which represent the cost of occupying offices in various locations throughout the world, decreased $4 million, or 5%, in the first quarter of 2024 compared to the prior year period, reflecting a reduction to our real estate footprint.

Depreciation of Fixed Assets

Depreciation of fixed assets primarily relates to software, leasehold improvements, furniture, fixtures, and equipment, computer equipment, buildings, and automobiles. Depreciation of fixed assets increased $6 million, or 16%, in the first quarter of 2024 compared to the prior year period due primarily to ongoing investments in Aon Business Services-enabled technology platforms to drive long-term growth.

Amortization and Impairment of Intangible Assets

Amortization and impairment of intangible assets primarily relates to finite-lived customer-related and contract-based assets as well as technology and other assets. Amortization and impairment of intangible assets decreased $9 million, or 36% in the first quarter of 2024 compared to the prior year period due primarily to ongoing portfolio management and a decrease associated with assets fully amortized in the prior year period.

Other General Expense

Other general expenses increased $19 million, or 6%, in the first quarter of 2024 compared to the prior year period primarily due to $15 million of transaction and integration costs associated with the acquisition of NFP.

Accelerating Aon United Program Expenses

Accelerating Aon United Program expenses were $119 million for the three months ended March 31, 2024, relating to workforce optimization, asset impairments, and technology and other costs.

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Interest Income

Interest income represents income, net of expense, earned on operating cash balances and other income-producing investments. It does not include interest earned on funds held on behalf of clients. During the first quarter of 2024, interest income increased $23 million to $28 million compared to the prior year period primarily reflecting interest earned on the investment of $5 billion of term debt proceeds which were used to fund the purchase of NFP.

Interest Expense

Interest expense, which represents the cost of our debt obligations, increased $33 million to $144 million during the first quarter of 2024 compared to the prior year period, reflecting an overall increase in total debt, primarily due to the issuance of $5 billion of term debt to fund the purchase of NFP, and higher interest rates.

Other Income (Expense)

Other income (expense) for the first quarter of 2024 increased $100 million compared to the prior year period. Other income was $75 million for the first quarter of 2024, primarily related to deferred consideration from the 2017 sale of our outsourcing business. Other expense was $25 million for the first quarter of 2023 primarily reflecting the unfavorable impact of exchange rates on the remeasurement of assets and liabilities in non-functional currencies and non-cash net periodic pension cost.

Income before Income Taxes

Due to the factors discussed above, Income before income taxes for the first quarter of 2024 was $1.4 billion, a 6% increase from $1.3 billion in the first quarter of 2023.

Income Taxes

The effective tax rate on Net income was 23.2% for the three months ended March 31, 2024. The effective tax rate on Net income was 19.6% for the three months ended March 31, 2023.

For the three months ended March 31, 2024, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, including the favorable impact of share-based payments offset by the unfavorable impact of discrete items.

For the three months ended March 31, 2023, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, primarily the favorable impact of share-based payments.

Ireland, the U.K., and many E.U. member states, among others, have enacted legislation to implement the global minimum tax that are consistent with the OECD’s proposed Pillar Two tax regime. There remains significant uncertainty, however, as to how Ireland’s Pillar Two tax regime and the OECD’s past and potentially future Pillar Two guidance will ultimately apply to the Company. The Company is monitoring developments in this area and continues to evaluate the potential impacts this may have on its global effective tax rate, results of operations, cash flows, and financial condition in 2024.

Net Income Attributable to Aon Shareholders

Net income attributable to Aon shareholders for the first quarter of 2024 increased to $1.1 billion, or $5.35 per diluted share, from $1.1 billion, or $5.07 per diluted share, in the prior year period.

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 Condensed 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 ongoing 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 (including held for sale disposal groups), 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 Condensed 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):

	Three Months Ended March 31,
	2024		2023		% Change		Less: Currency Impact (1)		Less: Fiduciary Investment Income (2)		Less: Acquisitions, Divestitures & Other Items		Organic Revenue Growth (3)
Revenue
Commercial Risk Solutions	$	1,808	$	1,778	2	%	1	%	1	%	(3)	%	3	%
Reinsurance Solutions	1,167		1,077		8		—		1		—		7
Health Solutions	733		671		9		1		—		2		6
Wealth Solutions	370		350		6		2		—		—		4
Eliminations	(8)		(5)		N/A		N/A		N/A		N/A		N/A
Total revenue	$	4,070	$	3,871	5	%	1	%	1	%	(2)	%	5	%

(1)Currency impact represents the effect on prior year period results if they were translated at current period foreign exchange rates.

(2)Fiduciary investment income for the three months ended March 31, 2024 and 2023, was $79 million and $52 million, respectively.

(3)Organic revenue growth includes the impact of certain intercompany activity and excludes the impact of changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures (including held for sale disposal groups), 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 our core operating performance. Adjusted operating margin 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 operating margin represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Condensed Consolidated Financial Statements.

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

	Three Months Ended March 31,
	2024			2023
Revenue	$	4,070		$	3,871
Operating income - as reported	$	1,465		$	1,473
Amortization and impairment of intangible assets	16			25
Accelerating Aon United Program expenses (1)	119			—
Transaction and integration costs (2)	15			—
Operating income - as adjusted	$	1,615		$	1,498
Operating margin - as reported	36.0		%	38.1		%
Operating margin - as adjusted	39.7		%	38.7		%

(1)Total charges are expected to include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation and technology costs.

(2)In the fourth quarter of 2023, Aon entered into a definitive agreement to acquire NFP, which closed on April 25, 2024. As part of the acquisition, Aon incurred $11 million of transaction costs in the three months ended March 31, 2024 including advisory, legal, accounting, regulatory, and other professional or consulting fees required to complete the acquisition. The NFP acquisition also will result in certain non-recurring integration costs associated with colleague severance, termination of redundant third-party agreements, costs associated with legal entity rationalization, and professional or consulting fees related to alignment of management processes and controls, as well as costs associated with the assessment of NFP information technology environment and security protocols. Aon incurred $4 million of integration costs in the three months ended March 31, 2024.

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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 Condensed 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):

	Three Months Ended March 31, 2024
	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income	$	1,465		$	150	$	1,615
Interest income	28			—		28
Interest expense	(144)			—		(144)
Other income (expense) (1)	75			(82)		(7)
Income before income taxes	1,424			68		1,492
Income tax expense (2)	331			6		337
Net income	1,093			62		1,155
Less: Net income attributable to noncontrolling interests	22			—		22
Net income attributable to Aon shareholders	$	1,071		$	62	$	1,133
Diluted net income per share attributable to Aon shareholders	$	5.35		$	0.31	$	5.66
Weighted average ordinary shares outstanding - diluted	200.1			—		200.1
Effective tax rates (2)	23.2		%			22.6		%

	Three Months Ended March 31, 2023
	U.S. GAAP			Adjustments		Non-GAAP Adjusted
Operating income	$	1,473		$	25	$	1,498
Interest income	5			—		5
Interest expense	(111)			—		(111)
Other income (expense)	(25)			—		(25)
Income before income taxes	1,342			25		1,367
Income tax expense (2)	263			5		268
Net income	1,079			20		1,099
Less: Net income attributable to noncontrolling interests	29			—		29
Net income attributable to Aon shareholders	$	1,050		$	20	$	1,070
Diluted net income per share attributable to Aon shareholders	$	5.07		$	0.10	$	5.17
Weighted average ordinary shares outstanding - diluted	207.1			—		207.1
Effective tax rates (2)	19.6		%			19.6		%

(1)In the first quarter of 2024, the Company earned $82 million of deferred consideration from the affiliates of The Blackstone Group L.P. and the other designated purchasers related to the 2017 sale of the benefits administration and business process outsourcing business.

(2)Adjusted items are generally taxed at the estimated annual effective tax rate, except for the applicable tax impact associated with the anticipated sale of certain assets and liabilities classified as held for sale, certain legal settlements, Program expenses, deferred consideration from a prior year sale of business, and certain transaction and integration costs related to the acquisition of NFP, which are adjusted at the related jurisdictional rate.

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Free Cash Flow

We use free cash flow, defined as cash flow provided by operations less 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, our Condensed Consolidated Financial Statements. Management believes the supplemental information related to free cash flow is helpful to investors when evaluating our operating performance and liquidity results. 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 the reported Cash provided by operating activities is as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Cash provided by operating activities	$	309	$	443
Capital expenditures	(48)		(76)
Free cash flow	$	261	$	367

Impact of Foreign Exchange Rate Fluctuations

Because we conduct business in over 120 countries and sovereignties, foreign exchange rate fluctuations may have a significant impact on our business. Foreign 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 rates 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 quarter’s revenue, expenses, and net income using the current quarter’s foreign exchange rates.

Currency fluctuations had a favorable impact of $0.02 on net income per diluted share during the three months ended March 31, 2024 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.14 on net income per diluted share during the three months ended March 31, 2023 if 2022 results were translated at 2023 rates.

Currency fluctuations had a favorable impact of $0.02 on adjusted diluted earnings per share during the three months ended March 31, 2024 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.14 on adjusted diluted earnings per share during the three months ended March 31, 2023 if 2022 results were translated at 2023 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 Condensed Consolidated 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, shareholder dividends, and Accelerating Aon United Program cash charges. 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 in Fiduciary assets in our Condensed Consolidated Statements of Financial Position, with a corresponding amount in Fiduciary liabilities.

In our capacity as an insurance broker or agent, we collect premiums from insureds and, after deducting our commission, remit the premiums to the respective insurance underwriters. We also collect claims or refunds from underwriters on behalf of insureds, which are then returned to the insureds. Unremitted insurance premiums and claims are held by us in a fiduciary capacity. The levels of funds held on behalf of clients and liabilities can fluctuate significantly depending on when we collect the premiums, claims, and refunds, make payments to underwriters and insureds, and collect funds from clients and make payments on their behalf, and upon the impact of foreign currency movements. Funds held on behalf of clients, because of their

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nature, are generally invested in highly 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 $7.1 billion and $6.9 billion at March 31, 2024 and December 31, 2023, respectively, and fiduciary receivables of $10.0 billion and $9.4 billion at March 31, 2024 and December 31, 2023, 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 multicurrency 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 March 31, 2024, cash balances of one or more non-U.S. 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 March 31, 2024 (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	$	995	$	—	$	4,294	$	5,289
Money market funds	—		5,413		2,823		8,236
Cash, Short-term investments, and funds held on behalf of clients	995		5,413		7,117		13,525
Fiduciary receivables	—		—		10,044		10,044
Total	$	995	$	5,413	$	17,161	$	23,569

Cash and cash equivalents and funds held on behalf of clients, including $73 million of cash and cash equivalents and funds held on behalf of clients classified as held for sale, increased $463 million in 2024. A summary of our cash flows provided by and used for operating, investing, and financing activities is as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Cash provided by operating activities	$	309	$	443
Cash provided by (used for) investing activities	$	(4,961)	$	205
Cash provided by financing activities	$	5,261	$	404
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	$	(146)	$	58
Net increase in cash and cash equivalents and funds held on behalf of clients	$	463	$	1,110

Operating Activities

Net cash provided by operating activities during the three months ended March 31, 2024 decreased $134 million from the prior year period to $309 million. This amount represents Net income reported, generally adjusted for 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, collection of receivables, and payments for Accelerating Aon United Program expenses.

Pension Contributions

Pension contributions were $17 million for the three months ended March 31, 2024, as compared to $23 million for the three months ended March 31, 2023. For the remainder of 2024, we expect to contribute approximately $51 million in cash to our pension plans, including contributions to non-U.S. pension plans, which are subject to changes in foreign exchange rates.

Accelerating Aon United Program Expenses

In the third quarter of 2023, we initiated the Program with the purpose of streamlining our technology infrastructure, optimizing our leadership structure and resource alignment, and reducing the real estate footprint to align to our hybrid working strategy. The Program will include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation and technology costs.

Program charges are recognized within Accelerating Aon United Program expenses on the accompanying Condensed Consolidated Statements of Income and consists of the following cost activities:

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•Technology and other – includes costs associated with actions taken to rationalize certain applications and to optimize technology across the Company. These costs may include contract termination fees and other non-capitalizable costs associated with Program initiatives, which include professional service fees.

•Workforce optimization – includes costs associated with headcount reduction and other separation-related costs.

•Asset impairments – includes costs associated with impairment of assets, as they are identified, including ROU lease assets, leasehold improvements, and other capitalized assets no longer providing economic benefit.

The changes in the Company’s liabilities for the Program as of March 31, 2024 are as follows (in millions):

	Technology and other		Workforce optimization		Asset impairments		Total
Liability Balance as of January 1, 2024	$	14	$	86	$	—	$	100
Charges	19		64		36		119
Cash payments	(12)		(25)		—		(37)
Foreign currency translation and other	—		(1)		—		(1)
Non-cash charges	(7)		(5)		(36)		(48)
Liability balance as of March 31, 2024	$	14	$	119	$	—	$	133
Total costs incurred from inception to date	$	33	$	167	$	54	$	254

The Program is currently expected to result in cumulative costs of approximately $1.0 billion, consisting of approximately $900 million of cash charges and approximately $100 million of non-cash charges. The Program is estimated to generate annualized expense savings of approximately $350 million by the end of 2026, largely benefiting Compensation and benefits, Information technology, and Premises on the Condensed Consolidated Statements of Income. For the three months ended March 31, 2024, total Program costs incurred were $119 million. The Company expects to continue to review the implementation of elements of the Program throughout the course of the Program and, therefore, there may be changes to expected timing, estimates of expected costs and related savings. We estimate that expense savings resulting from Program actions taken in 2023 will begin to be realized in 2024, including $20 million of savings realized in the first three months of 2024 within Compensation and benefits on the Condensed Consolidated Statements of Income.

Investing Activities

Cash flow used for investing activities was $4,961 million during the three months ended March 31, 2024, a decrease of $5,166 million compared to $205 million of Cash flow provided by investing activities in the prior year period. 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 our Condensed Consolidated Statements of Income.

Short-term Investments

As of March 31, 2024, short-term investments increased $5.0 billion to $5.4 billion compared to December 31, 2023. 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 the first three months of 2024, we completed no acquisitions. Cash consideration, net of cash and funds held on behalf of clients acquired, was $4 million, which relates to acquisitions completed in 2023. During the first three months of 2023, we completed no acquisitions. Cash consideration, net of cash and funds held on behalf of clients acquired, was $2 million, which relates to an acquisition completed in 2022.

During the first three months of 2024, we completed one disposition, which had an insignificant cash flow impact, however, we received $75 million of cash related to the deferred consideration earned in the first three months of 2024 for the 2017 sale of the benefits administration and business process outsourcing business. During the first three months of 2023, no businesses were sold, however, there was a $1 million impact, net of cash and funds held on behalf of clients, to the Condensed Consolidated Statements of Cash Flows related to dispositions completed in 2022.

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Capital Expenditures

Our additions to fixed assets, including capitalized software, amounted to $48 million and $76 million for the three months ended March 31, 2024 and 2023, respectively, which primarily relate to the refurbishing and modernizing of office facilities, software development costs, and computer equipment purchases. In the current period, we continue to support certain technology projects to drive long-term growth and real estate projects to align with our Smart Working strategy.

Financing Activities

Cash flow provided by financing activities during the three months ended March 31, 2024 was $5.3 billion, an increase of $4,857 million compared to $404 million of Cash flow provided by financing activities in the prior year period. Generally, the primary drivers of cash flow used for financing activities are repayments of debt, share repurchases, cash paid for employee taxes on withholding shares, dividends paid to shareholders, 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.

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 our share repurchase activity (in millions, except per share data):

	Three Months Ended March 31,
	2024		2023
Shares repurchased	0.8		1.8
Average price per share	$	310.56	$	305.31
Repurchase costs recorded to accumulated deficit	$	250	$	550

At March 31, 2024, the remaining authorized amount for share repurchase under the Repurchase Program was approximately $3.1 billion. Under the Repurchase Program, the Company has repurchased a total of 169.9 million shares for an aggregate cost of approximately $24.4 billion. For further information regarding the Repurchase Program, see Part II, Item 2 of this report.

Borrowings

Total debt at March 31, 2024 was $16.5 billion, an increase of $5.3 billion compared to December 31, 2023. Further, commercial paper activity during the three months ended March 31, 2024 and 2023 is as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Total issuances (1)	$	948	$	870
Total repayments	(1,539)		(1,043)
Net repayments	$	(591)	$	(173)

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

On March 1, 2024, Aon North America, Inc. issued $600 million 5.125% Senior Notes due in March 2027, $1 billion 5.150% Senior Notes due in March 2029, $650 million 5.300% Senior Notes due in March 2031, $1.75 billion 5.450% Senior Notes due in March 2034, and $2 billion 5.750% Senior Notes due in March 2054, totaling to an aggregate amount of $6 billion. The Company intends to use the net proceeds from the offering for general corporate purposes, including a portion of which that was used, together with the proceeds of the delayed draw term loan available under the credit agreement entered into on February 16, 2024 described below, to pay a portion of the cash consideration in connection with the acquisition of NFP, to repay certain debt of NFP and to pay related fees and expenses.

On February 16, 2024, Aon North America, Inc. entered into a credit agreement in which lenders committed to provide a $2 billion delayed draw term loan, which was subsequently drawn on April 25, 2024. The Company intends to use proceeds, together with the proceeds of the notes issued on March 1, 2024 described above, to pay a portion of the cash consideration in connection with the NFP acquisition, to repay certain debt of NFP and to pay related fees and expenses.

In November 2023, Aon Global Limited’s $350 million 4.00% Senior Notes matured and were repaid in full.

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In June 2023, Aon Global Limited’s $600 million 3.50% Senior Notes due June 2024 were classified as Short-term debt and current portion of long-term debt in the Condensed Consolidated Statement of Financial Position as the date of maturity is in less than one year.

On February 28, 2023, Aon Corporation and Aon Global Holdings plc co-issued $750 million 5.35% Senior Notes due in February 2033. The Company intends to use the net proceeds from the offering for general corporate purposes.

Other Liquidity Matters

Distributable Profits

We are required under Irish law to have available “distributable profits” to make share repurchases or pay dividends to shareholders. Distributable profits are created through the earnings of the Irish parent company and, among other methods, through intercompany dividends or a reduction in share capital approved by the High Court of Ireland. Distributable profits are not linked to a U.S. GAAP reported amount (e.g. Accumulated Deficit). As of March 31, 2024 and December 31, 2023, we had distributable profits in excess of $27.1 billion and $27.5 billion, respectively. We believe that we will have sufficient distributable profits for the foreseeable future.

Revolving Credit Facilities

We expect cash generated by operations for 2024 to be sufficient to service our debt and contractual obligations, finance capital expenditures, and continue to pay dividends to our shareholders. Although cash from operations is expected to be sufficient to service these activities, we have the ability to access the commercial paper markets or borrow under our credit facilities to accommodate any timing differences in cash flows. Additionally, under current market conditions, we believe that we could access capital markets to obtain debt financing for longer-term funding, if needed.

As of March 31, 2024, Aon had two primary committed credit facilities outstanding: its $1.0 billion multi-currency U.S. credit facility expiring in September 2027 and its $1.0 billion multi-currency U.S. credit facility expiring in October 2028. In aggregate, these two facilities provide $2.0 billion in available credit.

Each of these primary committed credit facilities and the delayed draw term loan 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 adjusted consolidated EBITDA, in each case, tested quarterly. Aon did not have borrowings under either of these primary committed credit facilities nor the delayed draw term loan as of March 31, 2024 and December 31, 2023, respectively. Additionally, Aon was in compliance with the financial covenants and all other covenants contained therein during the rolling 12 months ended March 31, 2024.

Subsequent Events

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp. in a cash-and-stock merger for an aggregate preliminary purchase price totaling $9.1 billion, with approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion.

On April 2, 2024, Aon plc announced that its wholly owned subsidiary, Randolph Acquisition Corp., commenced cash tender offers for any and all of the outstanding 6.875% Senior Notes due 2028, 4.875% Senior Secured Notes due 2028, 7.500% Senior Secured Notes due 2030 and 8.500% Senior Secured Notes due 2031, each issued by NFP Corp. (together, the “NFP Notes”), upon the terms and subject to the conditions set forth in the Offer to Purchase and Consent Solicitation Statement, dated as of April 2, 2024. On April 26, 2024, the Offeror purchased those NFP Notes that were validly tendered and not validly withdrawn prior to April 15, 2024, effecting the early settlement of the Offers (the “Early Settlement”). In addition, on April 16, 2024, NFP Corp. delivered notices of redemption of all NFP Notes not validly tendered pursuant to the Offers and purchased at the Early Settlement, at a purchase price equal to the price paid to holders of the NFP Notes in connection with the Early Settlement, with a redemption date of April 26, 2024. As a result of the Early Settlement of the Offers and the related redemption which occurred on April 26, 2024, no NFP Notes remain outstanding.

On April 20, 2024, Aon signed a definitive agreement to sell Healthy Paws, its U.S.-based managing general agent specializing in pet insurance, to Chubb Limited. Assets and liabilities associated with this disposal group were classified as held for sale as of March 31, 2024. The disposition is expected to be completed in the second quarter of 2024.

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Shelf Registration Statement

On June 22, 2023, 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 April 26, 2024 appear in the table below. 

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

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 letter of credit. We had total LOCs outstanding of approximately $139 million at March 31, 2024, compared to $86 million at December 31, 2023. These LOCs cover the beneficiaries related to certain of our U.S. and Canadian secure non-qualified pension plan schemes, reinsurance obligations related to our own E&O liability insurance program, 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 $110 million at March 31, 2024, compared to $194 million at December 31, 2023.

Guarantee of Registered Securities

Newly issued and outstanding debt securities by Aon Corporation are guaranteed by Aon Global Limited, Aon plc, Aon North America, Inc., 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, Aon North America, Inc., 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 Aon Corporation. There are no subsidiaries other than those listed above that guarantee the Aon Corporation Notes.

Newly issued and outstanding debt securities by Aon Global Limited are guaranteed by Aon plc, Aon Global Holdings plc, Aon North America, Inc., and Aon Corporation, and include the following (collectively, the “Aon Global Limited Notes”):

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Aon Global Limited Notes

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

Newly issued and outstanding debt securities by Aon North America, Inc. are guaranteed by Aon Global Limited, Aon plc, Aon Global Holdings plc, and Aon Corporation, and include the following (collectively, the “Aon North America, Inc. Notes”):

Aon North America, Inc. Notes

5.125% Senior Notes due March 2027

5.150% Senior Notes due March 2029

5.300% Senior Notes due March 2031

5.450% Senior Notes due March 2034

5.750% Senior Notes due March 2054

All guarantees of Aon Global Limited, Aon plc, Aon Global Holdings plc, and Aon Corporation of the Aon North America, Inc. 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 Aon North America, Inc. There are no subsidiaries other than those listed above that guarantee the Aon North America, Inc. 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, Aon North America, Inc., 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

5.35% Senior Notes due February 2033

2.90% Senior Notes due August 2051

3.90% Senior Notes due February 2052

All guarantees of Aon plc, Aon Global Limited, and Aon North America, Inc. 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 North America, Inc., 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, Aon North America, Inc., and Aon Corporation together comprise the revised “Obligor group”. The following tables set forth summarized financial information for the revised Obligor group, which reflects the financial results of Aon North America, Inc. for the year ended December 31, 2023 and for the period ended March 31, 2024.

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Adjustments are made to the tables to eliminate intercompany balances and transactions between the revised Obligor group. Intercompany balances and transactions between the revised 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 revised Obligor group in non-guarantor subsidiaries.

	Obligor Group
	Summarized Statement of Income Information
		Three Months Ended
(millions)		March 31, 2024
Revenue		$	—
Operating loss		$	(30)
Expense from non-guarantor subsidiaries before income taxes		$	(37)
Net loss		$	(160)
Net loss attributable to Aon shareholders		$	(160)

	Obligor Group
	Summarized Statement of Financial Position Information
		As of		As of
(millions)		March 31, 2024		December 31, 2023
Receivables due from non-guarantor subsidiaries		$	3,482	$	1,431
Other current assets		5,309		230
Total current assets		$	8,791	$	1,661
Non-current receivables due from non-guarantor subsidiaries		$	10,867	$	10,873
Other non-current assets		1,293		1,228
Total non-current assets		$	12,160	$	12,101
Payables to non-guarantor subsidiaries		$	5,660	$	3,750
Other current liabilities		4,848		4,987
Total current liabilities		$	10,508	$	8,737
Non-current payables to non-guarantor subsidiaries		$	10,912	$	10,933
Other non-current liabilities		17,345		11,447
Total non-current liabilities		$	28,257	$	22,380

CRITICAL ACCOUNTING POLICIES AND ESTIMATES

There have been no changes in our critical accounting policies, which include revenue recognition, pensions, goodwill and other intangible assets, contingencies, share-based payments, income taxes, and Accelerating Aon United restructuring charges as discussed in our Annual Report on Form 10-K for the year ended December 31, 2023.

NEW ACCOUNTING PRONOUNCEMENTS

Note 2 “Accounting Principles and Practices” to our Financial Statements contained in Part I, Item 1 of this report contains a discussion of recently announced Securities and Exchange Commission final rules and their impact or future potential impact on our financial results, if determinable.

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Item 3.  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” in the Notes to Consolidated Financial Statements as discussed in Part II, Item 8 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 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 March 31, 2024, we have hedged approximately 45% of our U.K. subsidiaries’ expected exposures to U.S. dollar, euro, and Japanese yen transactions for the years ending December 31, 2024 and 2025, respectively. 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 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 quarter exchange rates, diluted earnings per share would have a favorable $0.02 impact during the three months ended March 31, 2024. Further, adjusted diluted earnings per share, a non-GAAP measure as defined and reconciled under the caption “Review of Consolidated Results — Adjusted Diluted Earnings Per Share,” would have a favorable $0.02 impact during the three months ended March 31, 2024 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 decrease in global short-term interest rates adversely affects our fiduciary investment income.

Item 4.   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 quarterly report of March 31, 2024. Based on this evaluation, our chief executive officer and chief financial officer concluded 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 appropriate statute, 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.

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 the quarter ended March 31, 2024 that have materially affected, or that are reasonably likely to materially affect, Aon’s internal control over financial reporting.

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Part II Other Information

Item 1. Legal Proceedings

See Note 15 “Claims, Lawsuits, and Other Contingencies” to our Financial Statements contained in Part I, Item 1 of this report, which is incorporated by reference herein.

Item 1A. Risk Factors

The risk factors set forth in the “Risk Factors” section in Part I, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2023 reflect certain risks associated with existing and potential lines of business and contain “forward-looking statements” as discussed in “Information Concerning Forward-Looking Statements” elsewhere in this report. Readers should consider them in addition to the other information contained in this report as our business, financial condition or results of operations could be adversely affected if any of these risks actually occur.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

Issuer Purchases of Equity Securities

The following information relates to the purchase of equity securities by Aon or any affiliated purchaser during each month within the first quarter of 2024:

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)
1/1/24 - 1/31/24	274,850	$	298.78	274,850	$	3,235,150,333
2/1/24 - 2/29/24	167,219	$	306.03	167,219	$	3,183,975,641
3/1/24 - 3/31/24	362,932	$	321.57	362,932	$	3,067,268,255
	805,001	$	310.56	805,001	$	3,067,268,255

(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.

Unregistered Sales of Equity Securities

We did not make any unregistered sales of equity in the first quarter of 2024.

Item 3. Defaults Upon Senior Securities

Not Applicable.

Item 4. Mine Safety Disclosures

Not Applicable.

Item 5. Other Information

On March 8, 2024, Darren Zeidel, Executive Vice President, General Counsel and Company Secretary of the Company, adopted a new Rule 10b5-1 trading plan. The plan’s maximum length is until December 31, 2024 and first trades will not occur until June 7, 2024, at the earliest. The plan is intended to permit Mr. Zeidel to sell 3,299 and 3,298 class A ordinary shares of Aon in two separate transactions.

The Company is reporting the following information in lieu of reporting on a Current Report on Form 8-K:

Disclosure Pursuant to Item 2.03 of Form 8-K: Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

On April 25, 2024, Aon North America, Inc. drew in full its $2 billion delayed draw term loan facility (the “Term Loan Facility”) pursuant to the Term Loan Credit Agreement dated as of February 16, 2024 (as amended, the “Term Loan Agreement”), among Aon North America, Inc., Aon, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Citibank, N.A., as administrative agent, and the lenders party thereto. The proceeds of the Term Loan Facility were used to pay a portion of the cash consideration in connection with the NFP acquisition, to repay certain debt of NFP and to pay related fees and expenses.

43

The Term Loan Facility will mature on April 23, 2027, and 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.

The foregoing summary is qualified in its entirety by reference to the Term Loan Agreement and Amendment No. 1 to the Term Loan Agreement, copies of which are filed herewith as Exhibit 10.4 and Exhibit 10.5, respectively, and incorporated herein by reference.

Item 6. Exhibits 

Exhibits — The exhibits filed with this report are listed on the attached Exhibit Index.

44

Signature

Pursuant to the requirements 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
	(Registrant)
April 26, 2024	By:	/s/ Michael Neller
	Michael Neller
	SENIOR VICE PRESIDENT AND
	GLOBAL CONTROLLER
	(Principal Accounting Officer and duly authorized officer of Registrant)

45

Exhibit Index

Exhibit Number	Description of Exhibit
2.1	Agreement and Plan of Merger, by and among Aon plc, Randolph Acquisition Corp., Randolph Merger Sub LLC, NFP Intermediate Holdings A. Corp and NFP Parent Co, LLC, dated as of December 19, 2023 (incorporated by reference to Exhibit 2.1 to Aon’s Current Report on Form 8-K filed with the SEC on December 20, 2023).
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 with the SEC on June 4, 2021).
4.1	Base Indenture, dated as of March 1, 2024, among Aon North America, Inc., Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and The Bank of New York Mellon Trust Company, N.A. (Incorporated by reference to Exhibit 4.1 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.2	First Indenture Supplement, dated as of March 1, 2024, among Aon North America, Inc., Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and The Bank of New York Mellon Trust Company, N.A. (Incorporated by reference to Exhibit 4.2 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.3	Form of 5.125% senior unsecured 2027 Note (and guarantees thereof) (Incorporated by reference to Exhibit 4.3 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.4	Form of 5.150% senior unsecured 2029 Note (and guarantees thereof) (Incorporated by reference to Exhibit 4.4 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.5	Form of 5.300% senior unsecured 2031 Note (and guarantees thereof) (Incorporated by reference to Exhibit 4.5 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.6	Form of 5.450% senior unsecured 2034 Note (and guarantees thereof) (Incorporated by reference to Exhibit 4.6 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
4.7	Form of 5.750% senior unsecured 2054 Note (and guarantees thereof) (Incorporated by reference to Exhibit 4.7 to Aon plc’s Current Report on Form 8-K filed with the SEC on March 1, 2024).
10.1#	Amendment to Employment Agreement, dated as of April 2, 2024, by and among Aon plc, Aon Corporation and Gregory C. Case (Incorporated by reference to Exhibit 10.1 to Aon plc’s Current Report on Form 8-K filed with the SEC on April 3, 2024).
10.2#*	Aon plc Leadership Performance Program (as amended and restated, effective January 1, 2024).
10.3#*	Form of Restricted Stock Unit Agreement
10.4	Term Loan Credit Agreement, dated as of February 16, 2024, by and among, Aon North America, Inc., Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Citibank, N.A., as administrative agent, HSBC Securities (USA) Inc., JPMorgan Chase Bank, N.A., and Morgan Stanley Senior Funding, Inc. as syndication agents, and the lenders party thereto. (Incorporated by reference to Exhibit 10.2 to Aon plc’s Annual Report on Form 10-K filed with the SEC on February 16, 2024).
10.5	Amendment No. 1 to the Term Loan Credit Agreement, dated as of February 16, 2024, by and among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc., Citibank, N.A., as administrative agent, and the lenders party thereto (Incorporated by reference to Exhibit 10.1 to Aon plc’s Current Report on Form 8-K filed with the SEC on April 19, 2024).
10.6	Amendment No. 1 to the Credit Agreement, dated as of October 19, 2023, by and among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc., Citibank, N.A., as administrative agent, and the lenders party thereto. (Incorporated by reference to Exhibit 10.3 to Aon plc’s Annual Report on Form 10-K filed with the SEC on February 16, 2024).
10.7	Amendment No. 2 to the Credit Agreement, dated as of October 19, 2023, by and among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited and Aon North America, Inc., Citibank, N.A., as administrative agent, and the lenders party thereto (Incorporated by reference to Exhibit 10.2 to Aon plc’s Current Report on Form 8-K filed with the SEC on April 19, 2024).
10.8	Amendment No. 3 to the Credit Agreement, dated as of September 28, 2021, by and among Aon plc, Aon Corporation, Aon Global Holdings plc, Aon Global Limited, Aon UK Limited and Aon North America, Inc., Citibank, N.A., as administrative agent and the lenders party thereto. (Incorporated by reference to Exhibit 10.4 to Aon plc’s Annual Report on Form 10-K filed with the SEC on February 16, 2024).
10.9	Amendment No. 4 to the Credit Agreement, dated as of September 28, 2021, by and among Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon Corporation, Aon North America, Inc., Aon UK Limited, Citibank, N.A., as administrative agent, and the lenders party thereto (Incorporated by reference to Exhibit 10.3 to Aon plc’s Current Report on Form 8-K filed with the SEC on April 19, 2024).
22.1*	Subsidiary Guarantors and Issuers of Guaranteed Securities.
31.1*	Certification of CEO.
31.2*	Certification of CFO.
32.1*	Certification of CEO Pursuant to section 1350 of Title 18 of the United States Code.
32.2*	Certification of CFO Pursuant to section 1350 of Title 18 of the United States Code.

46

101*	Interactive Data Files. The following materials are filed electronically with this Quarterly Report on Form 10-Q:
	101.SCH XBRL Taxonomy Extension Schema Document
	101.CAL XBRL Taxonomy Calculation Linkbase Document
	101.DEF XBRL Taxonomy Definition Linkbase Document
	101.PRE XBRL Taxonomy Presentation Linkbase Document
	101.LAB XBRL Taxonomy Calculation Linkbase Document
104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)
* Filed herewith
# Indicates a management contract or compensatory plan or arrangement

47

EX-10.2

Table of Contents

Performance Award Certificate	3
Appendix A	4
Appendix B-1 [omitted]	10
Appendix B-2 [omitted]	17
Appendix B-3 [omitted]	23
Appendix C [omitted]	27
LPP Plan Document	56
LPP Goals and Payout Scales For 2024-2026 LPP [omitted]	63

LPP 2024-2026

LEADERSHIP PERFORMANCE PROGRAM

PERFORMANCE AWARD CERTIFICATE

In Connection with the Performance Cycle

January 1, 2024 through December 31, 2026

Aon plc (the “Company”) has determined that the following key member of the Company’s senior leadership team (the “Participant”) is eligible for participation in the Leadership Performance Program (the “Program”), effective for the Performance Cycle starting January 1, 2024 and ending December 31, 2026 ( “LPP 19”):

Participant’s Name: NAME

The Participant has been granted an Award of # SHARES Performance Share Units under LPP 19, which Performance Share Units will be subject to the terms and conditions set forth in the Program and this Performance Award Certificate, including Appendices A, B and C, which are attached hereto and made a part hereof (the “Agreement”). Capitalized terms not defined in this Agreement will have the meanings assigned under the Program and the Stock Plan.

Signed:

Lisa Stevens

Chief People Officer

Participant’s Acknowledgment:

The Participant (1) agrees and acknowledges that the Award of Performance Share Units is subject to the terms and conditions of this Agreement, the Program, and the Stock Plan; (2) agrees to be bound by the terms and conditions of this Agreement, the Program, and the Stock Plan, including the restrictive covenants contained in the Agreement and any Appendices; and (3) acknowledges that the Performance Share Units may be subject to increase, reduction or forfeiture as specified in the Program and the Stock Plan. Furthermore, the Participant understands and agrees that the Participant has no obligation to accept this Award (as a condition of employment or otherwise), and that the decision to do so by signing this Agreement, and thereby to accept all of the terms and conditions of this Agreement, is the Participant’s knowing and voluntary choice after having had a full and fair opportunity to consult with legal counsel (at the Participant’s cost).

The Participant agrees and acknowledges that, if the Participant is employed in or otherwise subject to the laws of Switzerland, Austria, Germany or Spain (or any other jurisdiction where the Participant has been informed that a handwritten acceptance is required), the Participant must sign this Agreement and return it to the Company within ninety (90) days. If the Participant does not sign and return this Agreement, the Participant will forfeit any rights to the Performance Share Units and will not receive any other benefit in lieu of the Performance Share Units, even if the Participant has electronically accepted the Performance Share Units.

Signed: Signed ElectronicallyDate: mm/dd/yyyy

Participant’s Signature

LPP 2024-2026

LPP 2024-2026

APPENDIX A

LEADERSHIP PERFORMANCE PROGRAM
PERFORMANCE AWARD CERTIFICATE
In Connection with Performance Cycle
January 1, 2024 through December 31, 2026

The following terms and conditions apply to all Participants unless otherwise noted herein or in Appendices B or C.

1.Governing Law. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to Appendix B to this Agreement, and the rights and obligations of the parties thereunder, will be governed by and construed in accordance with the substantive internal laws of the State of Illinois, without regard to the conflict of law principles, rules or statutes of any jurisdiction; provided, however, if Participant is a resident of California, Washington, Minnesota or Colorado, then for so long as Participant is a resident of California, Washington, Minnesota or Colorado, the law of Participant’s state of residence shall apply to the foregoing. The validity, interpretation, instruction, performance, enforcement and remedies of or relating to all other Sections of this Agreement, and the rights and obligations of the parties hereunder, will be governed by and construed in accordance with the substantive internal laws of the State of Delaware, without regard to the conflict of law principles, rules or statutes of any jurisdiction. The foregoing provisions of this Section 1 will apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may be governed by the laws of another jurisdiction (if any). Under no circumstances will the nonsolicit provisions in Sections 1.b), 1.c), and 1.d) or the notice provision in Section 1.g) of Appendix B-1 apply in California. Participant acknowledges that portions of this Agreement (including Appendix B) may be modified or overridden by the laws of the state in which Participant is based for work, and that these modifications or overrides are set forth in Appendix B-2 hereto, which constitutes part of the Agreement and which Participant has read and understands.

2.Venue and Jurisdiction. Venue for any legal proceedings instituted related to this Agreement will be exclusively in the state and/or federal courts located in Cook County, Illinois, and the Participant hereby knowingly, voluntarily and irrevocably agrees, consents and submits to the exclusive jurisdiction and venue of such courts within the State of Illinois. The Participant further hereby knowingly, voluntarily and irrevocably waives, and agrees not to assert, any objection, challenge or defense to such exclusive venue or jurisdiction (including without limitation any defense of forum non conveniens), and further agrees not to file any claim or action related to this Agreement in any other jurisdiction or venue. The foregoing provisions of this Section 2 will apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may provide for or permit venue or jurisdiction with respect to such other restrictive covenant in any other court or forum (if any).

3.No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding the Participant’s participation in the Program, or the acquisition or sale of Ordinary Shares. The Participant should consult with the

LPP 2024-2026

Participant’s own personal tax, legal and financial advisors regarding the Participant’s participation in the Program and execution of this Agreement, before executing this Agreement or otherwise taking any action at any time related to the Program.

4.Waiver; Section Headings. Waiver of any term or condition of this Agreement by any party will not be construed as a waiver of a subsequent breach or failure of the same term or condition, or a waiver of any other term or condition of this Agreement. Any waiver must be in writing. The section headings in this Agreement are for convenience only and are not to be used in interpreting this Agreement.

5.Severability. To the extent that the terms set forth in this Agreement or any word, phrase, clause or sentence is found to be illegal or unenforceable by a court of competent jurisdiction for any reason, such term, word, phrase, clause or sentence will be modified in such manner so as to afford the Company the fullest protection commensurate with making this Agreement, as modified, legal and enforceable under applicable laws. If, however, a court of competent jurisdiction finds that any such term, word, phrase, clause or sentence cannot be so modified and thus made enforceable, or otherwise declines for any reason to do so, such term, word, phrase, clause or sentence will be deemed severed from this Agreement and of no force and effect, and the balance of this Agreement will not be affected thereby, the balance being construed as severable and independent.

6.Intellectual Property. The Participant hereby assigns to the Company the Participant’s entire right, title and interest in and to all discoveries and improvements, patentable or otherwise, trade secrets and ideas and writings and copyrightable material, which are conceived, developed, reduced to practice, or acquired by the Participant (collectively, “IP”) during the Participant’s employment and which relate to the business of the Company or any of its Affiliates, parent companies or Subsidiaries. The Participant further acknowledges that all original works of authorship which are made by the Participant (solely or jointly with others) within the scope of and during the period of his/her employment with the Company and which are protectable by copyright are “works made for hire,” as that term is defined in the United States Copyright Act. The Participant agrees to disclose promptly, fully and in writing all such IP to the Company. The Participant will upon the Company’s request, execute, acknowledge and deliver to the Company all instruments and do all other acts which are necessary or desirable to enable the Company or any of its Affiliates, parent companies, or Subsidiaries to file and prosecute applications for, and to acquire, maintain and enforce, all patents, trademarks, and copyrights in all countries. To the extent the Participant is bound by an employee handbook or contract provision that protects the Company’s intellectual property at least to the extent provided in this Section 6, the provision set forth in such employment handbook or contractual arrangement between the Participant and the Company will prevail and govern.

7.Incentive Repayment Policies.

a.Incentive Repayment Policy for Section 16 Officers. If the Participant is an officer for purposes of Section 16 of the Exchange Act, the Participant is subject to Aon’s Incentive Repayment Policy for Section 16 Officers (the “Officers Repayment Policy”). The

LPP 2024-2026

Officers Repayment Policy provides that the Company will seek recoupment with respect to sale or all of the Award if (1) Aon plc is required to prepare an accounting restatement due to material noncompliance with any financial reporting requirement, (2) the amount of the Award is calculated based upon the achievement of financial results that were subsequently the subject of such a restatement, and (3) the amount received under the Award would have been lower if the financial results were properly reported. The Participant can obtain a copy of the Officers Repayment Policy from the Global Compensation team. If there is any conflict between this Agreement and the Officers Repayment Policy, such policy will control. If the Participant is subject to the Officers Repayment Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by such Policy.

b.Incentive Repayment Policy for Senior Executives (non-Section 16 Officers). If the Participant is member of the Aon Executive Committee (or any successor thereto) and not an officer of the Company for purposes of Section 16 of the Exchange Act, the Participant is subject to Aon’s Incentive Repayment Policy (For Senior Executives) (the “Senior Executives Repayment Policy”).  The Senior Executives Repayment Policy provides that Aon plc may seek recoupment with respect to some or all of the Award if (1) Aon plc is required to prepare an accounting restatement due to material noncompliance with any financial reporting requirement, (2) the amount of the Award is calculated based upon the achievement of financial results that were subsequently the subject of such a restatement, and (3) the amount received under the Award would have been lower if the financial results were properly reported. The Participant can obtain a copy of the Senior Executives Repayment Policy from the Global Compensation team.  If there is any conflict between this Agreement and the Senior Executives Repayment Policy, such policy will control. If the Participant is subject to the Senior Executives Repayment Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by such policy.

c.Malus and Clawback. If the Participant is a Material Risk Taker of Aon Securities Limited or Aon Investments Limited, then the Award is subject to Aon’s Material Risk Takers Variable Pay Adjustment Policy (the “MRT Policy”). The MRT Policy provides that Aon will have the discretion to cancel, or require reimbursement of, all or part of the Award in certain circumstances. The Participant can obtain a copy of the MRT Policy from their HR business partner. If the Participant is subject to the MRT Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by the MRT Policy including without limitation Aon’s discretion to cancel or require reimbursement of all or part of the Award in the circumstances set out within such policy.

8.Compliance with Law. Notwithstanding any other provision of the Program or this Agreement, unless there is an available exemption from any registration, qualification or other legal requirement applicable to the Ordinary Shares, the Company will not be required to deliver any Ordinary Shares issuable upon vesting/settlement of the Performance Share Units prior to the completion of any registration or qualification of the Ordinary Shares under any local, state, federal or foreign securities or exchange control law or under rulings or regulations of the U.S. Securities and Exchange Commission (“SEC”) or of any other governmental regulatory body, or prior to obtaining any approval or other clearance from any local, state, federal or foreign governmental agency, which registration, qualification or approval the Company will, in its

LPP 2024-2026

absolute discretion, deem necessary or advisable. The Participant understands that the Company is under no obligation to register or qualify the Ordinary Shares with the SEC or any state or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Ordinary Shares. Further, the Participant agrees that the Companywill have unilateral authority to amend the Program and the Agreement without the Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Ordinary Shares.

9.Appendices. Notwithstanding any provision of this Agreement to the contrary, if the Participant resides in a country outside the United States or is otherwise subject to the laws of a country other than the United States, the Performance Share Units will be subject to Appendix C to this Agreement. In addition, the terms of Appendix B-1 will apply if the Participant resides in the United States, the terms of Appendix B-2 will apply to the Participant’s specific state if a resident of the United States, and the terms of Appendix B-3 will apply if the Participant permanently resides in (or is otherwise remunerated through the local payroll of) a country outside the United States. Moreover, if the Participant relocates to one of the countries included in Appendix C, the special terms and conditions for such country will apply to the Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons.

10.Imposition of Other Requirements. The Company reserves the right to impose other requirements on the Participant’s participation in the Program, on the Performance Share Units and on any Ordinary Shares acquired under the Program, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require the Participant to sign or accept any additional agreements or undertakings that may be necessary to accomplish the foregoing.

11.Data Privacy.

The Participant is hereby notified of the collection, use and transfer, in electronic or other form, of the Participant’s personal data as described in this Agreement, any other Performance Share Units grant materials and the Company’sor, where applicable, the Subsidiary’s or Affiliate’s employing the Participant (the “Employer”) applicable employee Privacy Notice. Such personal data may be collected, used and transferred by and among, as applicable, the Company, the Employer, any other Subsidiary or Affiliate and any third parties assisting (presently or in the future) with the implementation, administration and management of the Program, such as Fidelity Stock Plan Services, LLC (“Fidelity”) or its successor for the exclusive purpose of implementing, administering and managing the Participant’s participation in the Program. Where required under applicable law, personal data also may be disclosed to certain securities or other regulatory authorities where the Company’s shares are listed or traded or regulatory filings are made, or to certain tax authorities for compliance with the Company’s, the Employer’s and/or the Participant’s tax obligations. The Participant understands that the collection, use and transfer of the Participant’s personal data is mandatory for compliance with applicable law and necessary for the performance of the

LPP 2024-2026

Program and that the Participant’s refusal to provide such personal data would make it impossible for the Company to perform its contractual obligations and may affect the Participant’s ability to participate in the Program.

12.Tax Withholding Obligations. The Participant acknowledges that, regardless of any action taken by the Company and/or the Employer, the ultimate liability for all income tax, social insurance contributions, payroll tax, payments on account or other tax-related items related to the Participant’s participation in the Program and legally applicable or deemed applicable to the Participant (“Tax-Related Items”), is and remains the Participant’s responsibility and may exceed the amount, if any, actually withheld by the Company or the Employer. The Participant further acknowledges that the Company and/or the Employer: (a) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the grant of Performance Share Units or the underlying Shares, including, but not limited to, the grant, vesting or settlement of the Performance Share Units, the issuance of Ordinary Shares upon settlement of the Performance Share Units, the subsequent sale of Ordinary Shares acquired pursuant to such vesting/settlement and the receipt of any dividends and/or dividend equivalents; and (b) do not commit to and are under no obligation to structure the terms of the Award or any aspect of the Performance Share Units to reduce or eliminate the Participant’s liability for Tax-Related Items or achieve any particular tax result. Further, if the Participant is subject to Tax-Related Items in more than one jurisdiction, the Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction.

a)Prior to any relevant taxable or tax withholding event, as applicable, the Participant agrees to make adequate arrangements satisfactory to the Company or the Employer, to satisfy all Tax-Related Items. In this regard, the Participant authorises the Company and/or the Employer, or their respective agents, at the Company’s discretion, to satisfy the obligations with regard to all Tax-Related Items by one or a combination of the following: (i) withholding from any wages or other cash compensation payable to the Participant; or (ii) withholding in Ordinary Shares to be issued upon vesting/settlement of the Performance Share Units; or (iii) withholding from the proceeds of the sale of Ordinary Shares acquired upon vesting/settlement of the Performance Share Units either through a voluntary sale or through a mandatory sale arranged by the Company (on the Participant’s behalf pursuant to this authorisation without further consent); provided, however, that if the Participant is a Section 16 officer under the Exchange Act, as amended, the Committee will establish the method of withholding from alternatives (i) - (iii) herein.

b)The Company and/or the Employer may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates in the Participant’s jurisdiction(s), including maximum applicable rates. If Tax-Related Items are withheld in excess of the Participant’s actual tax liability, any over-withheld amount may be refunded to the Participant in cash by the Company or the Employer (with no entitlement to the equivalent in Ordinary Shares) or, if not refunded, the

LPP 2024-2026

Participant may seek a refund from the local tax, social security or other applicable authorities. If the obligation for Tax-Related Items is satisfied by withholding in Ordinary Shares, for tax purposes, the Participant will be deemed to have been issued the full number of Ordinary Shares subject to the vested Performance Share Units, notwithstanding that a number of Ordinary Shares are held back solely for the purpose of paying the Tax-Related Items.

c)Finally, the Participant will pay to the Company and/or the Employer any amount of Tax-Related Items that the Company and/or the Employer may be required to withhold as a result of the Participant’s participation in the Program that cannot be satisfied by the means previously described. The Company may refuse to deliver the Ordinary Shares or the proceeds of the sale of Ordinary Shares if the Participant fails to comply with the Participant’s obligations in connection with the Tax-Related Items.

d)Notwithstanding anything in this Section 12 to the contrary, to avoid a prohibited distribution under Code Section 409A in the case of a Participant who is subject to U.S. federal income tax (a “U.S. Taxpayer”), if Ordinary Shares underlying the Performance Share Units will be withheld (or sold on the Participant’s behalf) to satisfy any Tax-Related Items arising prior to the date of settlement of the Performance Share Units for any portion of the Performance Share Units that is considered “nonqualified deferred compensation” subject to Code Section 409A, then the number of Ordinary Shares withheld (or sold on the Participant’s behalf) will not exceed the number of Ordinary Shares that equals the liability for the Tax-Related Items.

13.Language. The Participant acknowledges that the Participant is proficient in the English language, or has consulted with an advisor who is proficient in English, so as to enable the Participant to understand the provisions of this Agreement and the Program. If the Participant has received this Agreement or any other document related to the Program translated into a language other than English, and if the meaning of the translated version is different than the English version, the English version will control.

14.Insider Trading Restrictions/Market Abuse Laws. The Participant may be subject to insider trading restrictions and/or market abuse laws based on the exchange on which the Ordinary Shares are listed and in applicable jurisdictions, including the United States, the Participant’s country or the designated broker’s country, which may affect the Participant’s ability to accept, acquire, sell or otherwise dispose of Ordinary Shares, rights to Ordinary Shares (e.g., Performance Share Units) or rights linked to the value of Ordinary Shares (e.g., dividend equivalents) under the Program during such times as the Participant is considered to have “inside information” regarding the Company (as defined by the laws in applicable jurisdictions). Local insider trading laws and regulations may prohibit the cancellation or amendment of orders the Participant placed before the Participant possessed inside information. Furthermore, the Participant could be prohibited from (i) disclosing the inside information to any third party, including fellow employees and (ii) “tipping” third parties or causing them otherwise to buy or sell securities. Any restrictions under these laws or regulations are separate from and in addition

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to any restrictions that may be imposed under any applicable insider trading policy of the Company. The Participant acknowledges that it is the Participant’s responsibility to comply with any applicable restrictions, and the Participant should speak with the Participant’s own personal tax, legal and financial advisors regarding same.

15.Exchange Control, Foreign Asset/Account and/or Tax Reporting. Depending upon the country to which laws the Participant is subject, the Participant may have certain foreign asset/account and/or tax reporting requirements that may affect the Participant’s ability to acquire or hold Ordinary Shares under the Program or cash received from participating in the Program (including from any dividends or dividend equivalents or sale proceeds arising from the sale of Ordinary Shares) in a brokerage or bank account outside the Participant’s country of residence. The Participant’s country may require that the Participant report such accounts, assets or transactions to the applicable authorities in the Participant’s country. The Participant also may be required to repatriate cash received from participating in the Program to the Participant’s country within a certain period of time after receipt. The Participant is responsible for knowledge of and compliance with any such regulations and should speak with the Participant’s own personal tax, legal and financial advisors regarding same.

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AON PLC

LEADERSHIP PERFORMANCE PROGRAM

As Amended and Restated Effective January 1, 2024

1.Overview

The Leadership Performance Program (the “Program”) of Aon plc (the “Company”) has been adopted by the Organization and Compensation Committee of the Company’s Board of Directors (the “Committee) as a sub-plan of the Aon plc 2011 Incentive Plan, as it may be amended from time to time (the “Stock Plan”). Capitalized terms not defined herein will have the meaning assigned under the Stock Plan. The Program and all Awards issued hereunder are subject to the terms and conditions of the Stock Plan; in the event of any inconsistency between the Program and the Stock Plan, the Stock Plan will control to the extent consistent with applicable law.

2.Performance Cycle

The “Performance Cycle” means a three-year period commencing on the first day of the first calendar year of the three-year period, over which performance (as determined by the Committee) will be measured for purposes of the Program. A Performance Cycle may overlap with any other Performance Cycle under the Program.

3.Eligibility

As recommended by the Company’s Chief Executive Officer (the “CEO”) and approved by the Committee, key members of the Company’s senior leadership team are eligible to participate in the Program. The CEO is also eligible to participate in the Program as approved by the Committee.

4.Participation

The Committee will approve in writing by June 30 of the first year of the Performance Cycle (unless the Committee determines otherwise) the specific individuals eligible to participate in the Program (the “Participants”), each Participant’s Award (denominated as described below), the Target Earnings Per Share (as defined below), the Threshold Earnings Per Share (as defined below), the Payout Scale (as defined below), and any other performance measures that will apply during the Performance Cycle. Participants approved by the Committee will be eligible to participate in the full Performance Cycle, retroactive to the first day of the Performance Cycle. A change in a Participant’s position or role during the Performance Cycle will not affect the terms of any outstanding Award held by the Participant, subject to the Participant’s continued employment with the Company.

5.Performance Share Units

Each Participant’s Award will be denominated in either US dollars or as a target number of performance share units (“Performance Share Units”), each representing a Class A Ordinary Share of the Company (an “Ordinary Share”). Unless determined otherwise by the Committee, if the Award is denominated in US dollars, the target number of Performance Share Units under such Award will be derived by dividing the

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Award by the Fair Market Value of an Ordinary Share on the date the Award is approved in writing by the Committee (the “Grant Date”).

6.Rules Applicable to Performance Share Units

(a)To the extent earned, the Performance Share Units will vest as of the date the Committee determines and certifies in writing whether and to what extent the applicable performance criteria have been achieved and the resulting payout (the “Settlement Date”), which will occur as soon as administratively practicable following the end of the Performance Cycle.

(b)The number of Ordinary Shares into which the Performance Share Units settle upon vesting of such Performance Share Units (i) will be determined based on the Company’s actual cumulative Adjusted Earnings Per Share during the Performance Cycle, as compared to the Target Earnings Per Share, and subject to any such other performance conditions as may be determined by the Committee, and (ii) will range from 0% to 200% of the target number of Performance Share Units awarded, as set forth in the Payout Scale.

(c)The Performance Share Units will settle into Ordinary Shares during the calendar year immediately following the end of the Performance Cycle.

(d)The Company will have the right to satisfy all federal, state and local withholding tax requirements with respect to a settled Award by withholding Ordinary Shares equivalent in value to the amount of the required withholding (based on the Fair Market Value of an Ordinary Share on the Settlement Date).

(e)The Performance Share Units are not transferable and may not be sold, assigned, pledged, hypothecated or otherwise encumbered.

(f)Until the Settlement Date, the Participant will not be treated as a shareholder as to those Ordinary Shares relating to the Performance Share Units. No cash or other payments will be provided for dividend equivalents or other distributions.

(g)Each Award will be evidenced by a Performance Award Certificate (the “Certificate”) issued to the Participant. The Certificate, inclusive of its appendices, will set forth the target number of Performance Share Units granted to the Participant, among other terms and conditions. The Participant must sign and return to the Company the Certificate to indicate that the Participant agrees to be bound by the provisions of the Program, including, but not limited to, any restrictive covenants set forth in the Certificate. Failure to return a signed Certificate to the Company will result in forfeiture of the Performance Share Units.

(h)Notwithstanding anything herein to the contrary, if a Participant’s employment with the Company terminates before the last day of the Performance Cycle, the following rules will apply to the vesting and settlement of the Performance Share Units, unless determined otherwise by the Committee:

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Termination Event	Impact on Performance Share Units
Retirement (solely for Participants whose principal place of work is outside the EU or UK) Termination by Company without Cause Termination by Participant for Good Reason	If such Termination Event occurs one year or more after the Grant Date: The Participant will vest in a fraction (determined based on the number of full calendar quarters completed in the Performance Cycle as of the Participant’s termination date, as compared to the total number of calendar quarters in the Performance Cycle) of the Performance Share Units that would have vested and settled following the end of the Performance Cycle based on actual cumulative Adjusted EPS achieved during the Performance Cycle determined in accordance with the Payout Scale, as follows: Notwithstanding the foregoing, if the Participant is subject to an employment contract with the Company that has been approved by the Committee or the Board and specifies a fixed term of employment (an “Employment Term”), then such Participant may apply to the Committee for, and the Committee (or the independent members of the Board, in the case of the Chief Executive Officer) may permit, in its or their sole discretion, continued vesting of the Performance Share Units in accordance with their terms following such Termination Event (without regard to the continued employment vesting condition) if the Participant (i) was at least age 60 with a minimum of 20 years of continuous employment with the Company on the Grant Date of such Performance Share Units, (ii) completes the Employment Term in accordance with the provisions of the employment contract, having provided substantive services for the duration of the employment contract, (iii) has provided the Committee with a minimum of 60 days of advance notice of termination, and (iv) remains in compliance with all other obligations to the Company through the Termination Event and thereafter. To the extent earned, Performance Share Units will be settled in Ordinary Shares in accordance with Section 6(c) above. If such Termination Event occurs less than one year after the Grant Date: Performance Share Units will be forfeited in their entirety.
Death or Total and Permanent Disability	If the Participant’s death or Total and Permanent Disability occurs in the first or second calendar years of the Performance Cycle, the Participant (or the Participant’s estate) will vest in the target number of Performance Share Units, which will be settled in Ordinary Shares as soon as administratively feasible following such death or Total and Permanent Disability. If the Participant’s death or Total Permanent Disability occurs in the third calendar year of the Performance Cycle, the Participant (or the Participant’s estate) will vest in the target number of Performance Share Units or, if greater, the number of Performance Share Units earned based on actual cumulative Adjusted EPS during the Performance Cycle, determined in accordance with the Payout Scale. Performance Share Units will be settled in Ordinary Shares in accordance with Section 6(c) above.

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Voluntary Resignation (other than for Good Reason)	Performance Share Units will be forfeited in their entirety.
Termination by Company for Cause	Performance Share Units will be forfeited in their entirety.
Certain Terminations Following a Change in Control	Following a Change in Control, the Performance Share Units will be subject to the following rules: (i)If the Participant’s employment is terminated by the Company without Cause or by the Participant for Good Reason after the Change in Control but prior to the end of the Performance Cycle, the Participant’s Performance Share Units will immediately vest at the greater of the target Performance Share Units or the number of units that would have been earned based on the proportion of achievement of the Target Earnings Per Share as of the last full calendar quarter preceding or on the Participant’s termination date. Performance Share Units will be settled in Ordinary Shares upon, or as soon as administratively feasible following, the Participant’s termination of employment. (ii)If the Participant’s employment is terminated by the Company for Cause, by the Participant other than for Good Reason, or by reason of the Participant’s death or Total and Permanent Disability, the terms of the Program will continue to apply to the Performance Share Units as if the Change in Control had not occurred. (iii)If the Company is not the ultimate parent entity following the Change in Control, then all Performance Share Units will be converted into rights to acquire shares of the ultimate parent entity in accordance with Section 5.2 of the Stock Plan, and performance measures will be based on performance of the ultimate parent company (subject to adjustment in accordance with Section 5.2 of the Stock Plan), and not the Company.

(i)Notwithstanding the foregoing, in the event an individual employment agreement or other binding individual written arrangement between a Participant and the Company provides for more favorable vesting of Performance Share Units upon termination of employment or includes restrictive covenants specifically intended to apply to Awards under the Program, the provisions of such employment agreement or binding written arrangement will control if such provisions are approved by the Committee on or before the Grant Date.

(j)Notwithstanding the foregoing, if the successor to the Company in connection with a Change in Control does not assume and continue this Program substantially in its current form, the Performance Share Units will become immediately vested at the greater of the target Performance Share Units or the number of units that would have been earned based on the proportion of achievement of the Target Earnings Per Share as of the last full calendar quarter as of or

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preceding the effective date of the Change in Control. Such Units will be settled in Ordinary Shares upon, or as soon as practicable following, the Change in Control.

(k)In the event that the Company’s Chief Executive Officer determines (or, in the case of the Chief Executive Officer as Participant, the Board determines), in the Chief Executive Officer’s or the Board’s sole discretion, as applicable, that forfeiture is appropriate based on the finding that (i) the Participant has materially violated Company policies and procedures, including, but not limited to, performing an act of race, sex, national origin, religion, disability, or age-based discrimination, or sexual harassment or any other material violation of the Aon Code of Business Conduct, or (ii) the Participant is in breach of any non-competition, non-solicitation, and/or confidentiality provisions or other restrictive covenants that apply to the Participant, all unvested Performance Share Units will be forfeited.

7.Performance Measures for Performance Share Units

The performance measure for the Performance Share Units will be expressed as a target cumulative Adjusted Earnings Per Share for the Performance Cycle, as approved by the Committee by resolution (the “Target Earnings Per Share”).

The Committee may establish performance measures for the Performance Share Units in addition to target cumulative Adjusted Earnings Per Share for the Performance Cycle, including, but not limited to, share price hurdles.

Following the end of the Performance Cycle, the Committee will determine in its sole discretion the payout, which determination will be final and binding. Performance Share Units will be subject to complete forfeiture if the Company’s performance for the Performance Cycle does not meet or exceed the minimum cumulative Adjusted Earnings Per Share (the “Threshold Earnings Per Share”) or other performance hurdles approved by the Committee by resolution, and the payout for performance at or above the Threshold Earnings Per Share will be calculated using the “Applicable Percentage” as set forth on the payout scale approved by the Committee by resolution (the “Payout Scale”).

8.Adjustments to Performance Measures or Results

The Committee will make appropriate adjustments to actual Adjusted Earnings Per Share to take into account material and/or significant items or events as publicly reported in the Company’s annual Form 10-K or quarterly Form 10-Q, including, but not limited to, the following and to the extent consistent with the Stock Plan, as amended: gain/loss on disposition of assets or business; extraordinary legal/regulatory judgments, settlements, fines, penalties, and other related expenses; extraordinary market conditions; effects of natural or man-made disasters (e.g., World Trade Center); hyperinflation (e.g., greater than 15%); foreign exchange impact; changes in applicable laws, regulations or accounting principles; and items that are unusual in nature and/or infrequently occurring. The Committee may not otherwise amend the Payout Scale in a manner that would be adverse to a Participant without the Participant’s consent.

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9.Nominal Value

As required under the Aon Ireland Constitution and the Irish Companies Act, at the time of settlement of Ordinary Shares under this Program, the settlement of Ordinary Shares will be subject to the Participant’s payment of a nominal value (as determined in the sole discretion of the Company and in accordance with such law, as amended from time to time), and such obligation may be satisfied by the Participant in any manner to be established by the Company in its sole discretion.

10.Restrictive Covenants

Awards under the Program will be subject to and contingent upon the Participant’s acceptance of and compliance with any restrictive covenants set forth in the applicable Performance Award Certificate.

11.Administration

It is expressly understood by the Participant that the Committee has the discretionary authority to administer, construe, and make all determinations necessary or appropriate to the administration of the Program, all of which will be binding upon the Participant. The Committee may delegate its authority to one or more of its members, or to one or more members of the Company’s senior management team, to offer participation in this Program to eligible individuals. The Company will, as necessary, adopt conforming amendments to this Program as are necessary to comply with applicable law.

12.General Provisions

All obligations of the Company under this Program with respect to payout of Awards, and the corresponding rights granted thereunder, will be binding on any successor to the Company, whether the existence of such successor is the result of a direct or indirect purchase, merger, consolidation or other acquisition of all or substantially all of the business and/or assets of the Company.

This Program, together with the Stock Plan and any applicable Performance Award Certificate, constitutes a legal document which governs all matters involved with its interpretation and administration and supersedes any writing or representation inconsistent with its terms.

13.Reservation and Retention of Company Rights

The selection of any individual for participation in this Program will not give that Participant any right to be retained in the employ of the Company. No Participant will at any time have a right to be selected for participation in a future performance-based incentive program despite having been selected for participation in this Program or a previous program.

14.Code Section 409A

The Company intends that this Program and the Awards granted hereunder to U.S. participants be interpreted and construed to be exempt from, or otherwise comply with, Code Section 409A to the extent applicable thereto. Notwithstanding any provision of the Program to the contrary, the Program will be interpreted and construed consistent with this intent, provided that the Company will not be required to assume any increased economic burden in connection therewith. With respect to any payment subject to Code Section 409A that is triggered by a “specified employee’s” “separation from service” under Code

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Section 409A (as such terms are defined under Code Section 409A), such payment will be delayed until the earlier to occur of the Participant’s death or the date that is six months and one day following the Participant’s termination of employment (the “Delay Period”). Upon the expiration of the Delay Period, all payments delayed pursuant to this section will be paid to the Participant. For purposes of the Program, the terms “retirement,” “termination of employment,” “terminated,” “termination,” and variations thereof, as used in this Program, will mean a “separation from service” under Code Section 409A. The time or schedule of any payout of Ordinary Shares pursuant to Performance Share Units may not be accelerated for U.S. participants except as otherwise permitted under Code Section 409A. Although the Committee intends to administer the Program so that it will comply with the applicable requirements of Code Section 409A, neither the Company nor the Committee represents or warrants that the Program will comply with Code Section 409A or any other provision of federal, state, local, or non-United States law. Neither the Company, its Subsidiaries, nor their respective directors, officers, employees or advisers will be liable to any Participant (or any other individual claiming a benefit through any Participant) for any tax, interest, or penalties any participant may owe as a result of compensation paid under the Program, and the Company and its subsidiaries will have no obligation to indemnify or otherwise protect the Participant from the obligation to pay any taxes pursuant to Code Section 409A.

15.Definitions

(a)“AdjustedEarnings Per Share” or “AdjustedEPS” means the Company’s adjustedearnings per share from continuing operations as publicly reported each quarter, and on an annual basis, in the Company’s earnings release and Form 10-K.

(b)“Cause” means such term as defined in any written binding individual employment agreement entered into between the Participant and the Company and approved by the Committee prior to the Grant Date, or, in the absence of any such agreement or defined term, means the Participant’s: (1) performance of a deliberate act of dishonesty, fraud, theft, embezzlement or misappropriation involving the Participant’s employment with the Company, its Subsidiaries, or Affiliates, or breach of the duty of loyalty to the Company, its Subsidiaries, or Affiliates; (2) performance of an alleged act of race, sex, national origin, religion, disability, or age-based discrimination or sexual harassment, if after a reasonable investigation, outside or in-house counsel to the Company, its Subsidiaries, or Affiliates reasonably concludes that the allegations are substantiated; (3) material violation of Company policies and procedures including, but not limited to, the Aon Code of Business Conduct; (4) material noncompliance with any terms of this Agreement or an employment agreement with the Company, its Subsidiaries, or Affiliates; or (5) performance of a criminal act resulting in a criminal felony charge (or equivalent offense in a non-US jurisdiction) brought against the Participant or a criminal conviction of the Participant (other than a conviction of a minor traffic violation). The existence of “Cause” will be determined by the Committee in its sole discretion.

(c)“Code Section 409A” means Section 409A of the Internal Revenue Code of 1986, as amended, and all regulatory or other interpretive guidance issued thereunder.

(d)“Fair Market Value” means the per share value of the Ordinary Shares as determined by using the closing price of such shares as reported by the New York Stock Exchange on such date (or, if the

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New York Stock Exchange was not open for trading or the shares were not traded on that day, the next preceding day that the New York Stock Exchange was open for trading and Ordinary Shares were traded).

(e)“Good Reason” means such term as defined in any written binding individual employment agreement entered into between the Participant and the Company and approved by the Committee prior to the Grant Date. If there is no such agreement, or such agreement does not define “Good Reason,” the Participant’s voluntary termination of employment will be treated as a voluntary resignation.

(f)“Retirement” means, solely with respect to a Participant whose principal place of work is outside the European Union or United Kingdom, a voluntary termination of employment upon or after the Participant’s attainment of age 55. For purposes of this definition, the principal place of work for a Participant on secondment will be considered to be the Participant’s home country. With respect to a Participant whose principal place of work is within the European Union or United Kingdom, the Participant’s voluntary termination of employment at any age will be treated as a voluntary resignation.

(g)“Total and Permanent Disability” means (1) for US employees, entitlement to long-term disability benefits under the Company’s long-term disability program, as amended from time to time, and (2) for non-US employees, such term as established by applicable Company policy or as required by applicable local law or regulations.

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EX-10.3

RESTRICTED STOCK UNIT AGREEMENT

UNDER THE

AON PLC 2011 INCENTIVE PLAN

This Restricted Stock Unit Agreement, including Appendices A, B and C attached hereto (the “Agreement”), is entered into between Aon plc, a public limited company incorporated under Irish law (the “Company” or “Aon”) and ________________________________(the “Participant”).

WHEREAS, the Company maintains the Aon plc 2011 Incentive Plan, as amended from time to time (the “Plan”), which provides for the grant of equity-based and cash incentive awards.

WHEREAS, the Company desires to grant the Participant restricted stock units (“RSUs”), each RSU representing the right to receive a Class A Ordinary Share of the Company (“Share”), $0.01 par value per Share, to encourage the Participant to remain in the service of the Company or its Subsidiaries, to provide the Participant with an incentive to contribute to the financial progress of the Company, and to encourage ownership of Shares by the Participant. Capitalized terms used but not otherwise defined in the Agreement will have the meaning ascribed to such terms in the Plan.

NOW, THEREFORE, in consideration of the mutual promises hereinafter set forth, the parties hereto agree as follows:

1.Grant of Restricted Stock Units. The Company grants under the Plan an award of __________ RSUs (the “Award”) on _______________ (the “Grant Date”). The Participant understands and agrees that the Participant has no obligation to accept this Award (as a condition of employment or otherwise) and that the Participant’s decision to do so by signing or accepting this Agreement, and thereby accepting all of the terms and conditions of this Agreement, is the Participant’s knowing and voluntary choice after having had a full and fair opportunity to consult with legal counsel (at the Participant’s cost).

2.Vesting of Restricted Stock Units. The RSUs will vest in accordance with the schedule set forth in the Participant’s account. The Participant must access the www.netbenefits.com website and follow the instructions in order to view the vesting schedule. Notwithstanding anything herein to the contrary, the Committee may cause the RSUs to vest prior to the date(s) set forth in the vesting schedule in order to satisfy any Tax-Related Items (as defined below) that arise prior to the date of settlement of the RSUs, subject to the limitations set forth in Section 3.d) of this Agreement.

3.Tax Withholding Obligations. The Participant acknowledges that, regardless of any action taken by the Company and/or the Participant’s employer (the “Employer”), the ultimate liability for all income tax, social insurance contributions, payroll tax, payments on account, or other tax-related items related to the Participant’s participation in the Plan and legally applicable or deemed applicable to the Participant (“Tax-Related Items”) is and remains the Participant’s responsibility and may exceed the amount, if any, actually withheld by the Company or the Employer. The Participant further acknowledges that the Company and/or the Employer: (1) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the Award or the underlying Shares, including, but not limited to, the grant, vesting, or settlement of the RSUs, the issuance of Shares upon settlement of the RSUs, the subsequent sale of Shares acquired pursuant to such vesting/settlement, and the receipt of any dividends and/or dividend equivalents; and (2) do not commit to and are under no obligation to structure the terms of the Award or any aspect of the RSUs to reduce or eliminate the Participant’s liability for Tax-Related Items or achieve any particular tax

result. Further, if the Participant is subject to Tax-Related Items in more than one jurisdiction, the Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction.

a)Prior to any relevant taxable or tax withholding event, as applicable, the Participant agrees to make adequate arrangements satisfactory to the Company or the Employer, to satisfy all Tax-Related Items. In this regard, the Participant authorises the Company and/or the Employer, or their respective agents, at the Company’s discretion, to satisfy the obligations with regard to all Tax-Related Items by one or a combination of the following:

(i)withholding from any wages or other cash compensation payable to the Participant; or

(ii)withholding in Shares to be issued upon vesting/settlement of the RSUs; or

(iii)withholding from the proceeds of the sale of Shares acquired upon vesting/settlement of the RSUs either through a voluntary sale or through a mandatory sale arranged by the Company (on the Participant’s behalf pursuant to this authorisation without further consent); provided, however, that if the Participant is a Section 16 officer under the Exchange Act, the Committee will establish the method of withholding from alternatives (i) – (iii) herein.

b)The Company and/or the Employer may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates in the Participant’s jurisdiction(s), including maximum applicable rates. If Tax-Related Items are withheld in excess of the Participant’s actual tax liability, any over-withheld amount may be refunded to the Participant in cash by the Company or the Employer (with no entitlement to the equivalent in Shares) or, if not refunded, the Participant may seek a refund from the local tax, social security or other applicable authorities. If the obligation for Tax-Related Items is satisfied by withholding in Shares, for tax purposes, the Participant will be deemed to have been issued the full number of Shares subject to the vested RSUs, notwithstanding that a number of Shares are held back solely for the purpose of paying the Tax-Related Items.

c)Finally, the Participant will pay to the Company and/or the Employer any amount of Tax-Related Items that the Company and/or the Employer may be required to withhold as a result of the Participant’s participation in the Plan that cannot be satisfied by the means previously described. The Company may refuse to deliver the Shares or the proceeds of the sale of Shares if the Participant fails to comply with the Participant’s obligations in connection with the Tax-Related Items.

d)Notwithstanding anything in this Section 3 to the contrary, to avoid a prohibited distribution under Code Section 409A in the case of a Participant who is subject to U.S. federal income tax (a “U.S. Taxpayer”), if Shares underlying the RSUs will be withheld (or sold on the Participant’s behalf) to satisfy any Tax-Related Items arising prior to the date of settlement of the RSUs for any portion of the RSUs that is considered “nonqualified deferred compensation” subject to Code Section 409A (“Deferred Compensation”), then the number of Shares withheld (or sold on the Participant’s behalf) will not exceed the number of Shares that equals the liability for the Tax-Related Items.

4.Nominal Value. At the time of settlement, this Award will be subject to the Participant’s appropriate undertaking to pay to the Company a nominal value of $.01 per share (as determined in the sole

discretion of the Company, subject to the provisions of the Aon Ireland Constitution and the Irish Companies Act), and such obligation may be satisfied by the Participant in cash in any manner to be established by the Company in its sole discretion, including, but not limited to, withholding from any wages or other cash compensation paid to the Participant by the Company and/or the Employer.

5.Effect of Termination of Employment; Breach of Restrictive Covenants; Misconduct.

a)Voluntary termination (other than Retirement). In the event that the Participant’s Termination Date occurs due to the Participant’s voluntary termination that does not qualify as Retirement (as defined in Section 5.d) below), all unvested RSUs will be forfeited.

b)Termination due to death. In the event that the Participant’s Termination Date occurs due to the Participant’s death, all unvested RSUs will be fully vested immediately, and the date of such termination will be considered a vesting date for purposes of the settlement provisions of Section  7 hereof.

c)Termination due to disability. In the event that the Participant’s Termination Date occurs due to the Participant’s disability, all unvested RSUs will be fully vested immediately, and the date of such termination will be considered a vesting date for purposes of the settlement provisions of Section  7 hereof. “Disability” for purposes of this Agreement, will mean disability pursuant to the standards set forth in the long-term disability plan of the Employer. In the absence of such a plan, the Committee will have exclusive discretion to determine whether a Participant’s employment is terminated due to disability.

d)Involuntary termination (other than for Cause) or Retirement. In the event that the Participant’s Termination Date occurs as a result of the Participant’s involuntary termination by the Company or Employer (other than for Cause as defined in Section 5.e) below) or the Participant’s Retirement, the RSUs will be immediately vested pro rata, and the date of such termination will be considered a vesting date for purposes of the settlement provisions of Section 7 hereof. The pro rata portion of the RSUs that will vest will be calculated by multiplying (i) the number of RSUs subject to the Award, by (ii) a fraction, the numerator of which will be the number of days that have elapsed between the Grant Date and the date of the Participant’s termination, and the denominator of which will be the total number of days from the Grant Date through the final vesting date set forth in the Participant’s account, and subtracting from the resulting product the number of RSUs previously vested. The remaining unvested portion of the RSUs will be forfeited. For purposes of this Agreement, “Retire” or “Retirement” means a voluntary termination of employment on or after the Participant’s 55th birthday for employees whose principal place of work is outside of the European Union (“EU”) or the United Kingdom. A Participant on secondment will be subject to the vesting rule applicable to the Participant’s home country. Participants whose principal place of work is inside the EU or the United Kingdom will not be eligible for Retirement, and their voluntary termination at any age will be treated in accordance with Section 5.a). The Committee will have exclusive discretion to determine a Participant’s principal place of work for purposes of this Section 5.d).

e)Termination for Cause. In the event that the Participant’s Termination Date occurs because the Participant is terminated by the Company or Employer for Cause, all unvested RSUs will be forfeited. “Cause” will mean the Participant’s (i) performance of a deliberate act of dishonesty, fraud, theft, embezzlement, or misappropriation involving the Participant’s employment with the Company, its Subsidiaries, or Affiliates, or breach of the duty of loyalty to the Company, its

Subsidiaries, or Affiliates; (ii) performance of an alleged act of race, sex, national origin, religion, disability, or age-based discrimination or sexual harassment, if after a reasonable investigation, outside or in-house counsel to the Company, its Subsidiaries, or Affiliates reasonably concludes that the allegations are substantiated; (iii) material violation of Company policies and procedures including, but not limited to, the Aon Code of Business Conduct; (iv) material noncompliance with any terms of this Agreement or an employment agreement with the Company, its Subsidiaries, or Affiliates; or (v) performance of any criminal act resulting in a criminal felony charge brought against the Participant or a criminal conviction of the Participant (other than conviction of a minor traffic violation). The existence of “Cause” will be determined by the Committee in its sole discretion.

f)Misconduct; Breach of Restrictive Covenants. All unvested RSUs will be forfeited in the event that the Company’s Chief Executive Officer determines (or, in the case of the Chief Executive Officer as Participant, the Board of Directors of the Company (the “Board”) determines), in the Chief Executive Officer’s or the Board’s sole discretion, as applicable, that forfeiture is appropriate based on the finding that (i) the Participant has materially violated Company policies and procedures, including (but not limited to) performing an act of race, sex, national origin, religion, disability, or age-based discrimination, or sexual harassment or any other material violation of the Aon Code of Business Conduct, or (ii) the Participant is in breach of any non-competition, nonsolicitation, and/or confidentiality provisions or other restrictive covenants that apply to the Participant.

6.Receipt by the Participant of the Prospectus. The Participant acknowledges receipt of the Plan prospectus that contains the entire Plan and is incorporated herein by reference. The Participant represents and warrants that the Participant has read the Plan and agrees that all RSUs awarded under it will be subject to all of the terms and conditions of the Plan.

7.Issuance of Shares. RSUs will be converted to Shares as of the applicable vesting date. Shares will be issued to the Participant as soon as practicable (within 60 days) after the vesting date, subject to Sections 3 and 4 of this Agreement. Notwithstanding the foregoing, for purposes of complying with Code Section 409A, if (i) the RSUs are considered Deferred Compensation, (ii) the Participant is a U.S. Taxpayer, and (iii) the Shares are to be settled in connection with a termination of service, then the Company and the Participant will take all steps necessary (including with regard to any post-termination services by the Participant) to ensure that a termination contemplated under Section 5 constitutes a “separation from service” within the meaning of Code Section 409A. In addition, if (i) the RSUs are Deferred Compensation, (ii) the Participant is a U.S. Taxpayer, (iii) the RSUs are payable in connection with the Participant’s separation from service, and (iv) the Participant is a “specified employee” within the meaning of Code Section 409A on the date the Participant experiences a separation from service, then the RSUs will be settled on the first business day of the seventh month following the Participant’s separation from service, or, if earlier, on the date of the Participant’s death, solely to the extent such delayed payment is required in order to avoid a prohibited distribution under Code Section 409A.

8.Rights as Shareholder. The Participant will not have voting or any other rights as a shareholder of the Company with respect to the RSUs. Upon issuance of the Shares pursuant to and in accordance with Section 7, the Participant will obtain full voting and other rights as a shareholder of the Company.

9.Other Provisions.

a)Plan Terms Take Precedence over Agreement Terms. RSUs are granted pursuant to the Plan, the terms and conditions of which are incorporated into this Agreement by reference. If there are any inconsistencies between the terms of this Agreement and the Plan, the terms of the Plan will govern.

b)Prior Agreement(s) Will Not Control. The Participant’s acceptance of this Agreement will supersede provisions of any prior agreement that could be construed as governing the terms of this Award.

c)Code Section 409A. The RSUs and amounts payable thereunder are intended to be exempt from or compliant with Code Section 409A and the U.S. Treasury Regulations relating thereto so as not to subject the Participant to the payment of additional taxes and interest under Code Section 409A or other adverse tax consequences. In furtherance of this intent, the provisions of this Agreement will be interpreted, operated, and administered in a manner consistent with these intentions. The Committee may modify the terms of this Agreement and/or the Plan, without the consent of the Participant, in the manner that the Committee may determine to be necessary or advisable in order to comply with Code Section 409A or to mitigate any additional tax, interest and/or penalties, or other adverse tax consequences that may apply under Code Section 409A if compliance is not practical. This Section 9.c) does not create an obligation on the part of the Company to modify the terms of this Agreement or the Plan and does not guarantee that the RSUs or the delivery of Shares upon vesting/settlement of the RSUs will not be subject to taxes, interest, penalties, or any other adverse tax consequences under Code Section 409A. Nothing in this Agreement will provide a basis for any person to take any action against the Company or any of its Subsidiaries or Affiliates based on matters covered by Code Section 409A, including the tax treatment of any amounts paid under this Agreement, and neither the Company nor any of its Subsidiaries or Affiliates will have any liability under any circumstances to the Participant or any other party if the RSUs, the delivery of Shares upon vesting/settlement of the RSUs, or other payment or tax event hereunder that is intended to be exempt from, or compliant with, Code Section 409A, is not so exempt or compliant, or for any action taken by the Committee with respect thereto. Further, settlement of any portion of the RSUs that is Deferred Compensation may not be accelerated or postponed except to the extent permitted by Code Section 409A.

d)Restriction on Transfer. RSUs may not be sold, transferred, pledged, assigned, or otherwise alienated at any time.

e)Right of Employment. Grants of RSUs under the Plan and this Agreement do not confer upon the Participant any right to continue in the employ or service of the Employer. This Agreement will survive any termination of the Participant’s employment for any or no reason.

f)Electronic Delivery and Acceptance. The Company may, in its sole discretion, decide to deliver any documents related to current or future participation in the Plan by electronic means. The Participant hereby consents to receive such documents by electronic delivery and agrees to participate in the Plan through an on-line or electronic system established and maintained by the Company or a third party designated by the Company.

g)Need to Accept Grant. The Participant acknowledges that this grant must be accepted within 90 days of the Grant Date in order to be eligible to receive any benefits from this grant. If this grant is not accepted within the 90-day period specified in the foregoing sentence, all benefits under this grant may be forfeited, as determined in the sole discretion of the Committee. To accept this

grant, the Participant must access the www.netbenefits.com website and follow the instructions for acceptance. If this grant was distributed to the Participant via mail, or if the Participant is employed in or otherwise subject to the laws of Austria, Germany, Spain, or Switzerland (or any other jurisdiction where the Participant has been informed that a handwritten acceptance is required), the Participant must sign the Agreement and return it to the Company within 90 days. If the Participant does not sign and return the Agreement within 90 days of the Grant Date, the Participant will forfeit any rights to the RSUs and will not receive any other benefit in lieu of the RSUs even if the Participant has electronically accepted the RSUs.

h)Waiver; Section Headings. Waiver of any term or condition of this Agreement by any party will not be construed as a waiver of a subsequent breach or failure of the same term or condition, or a waiver of any other term or condition of this Agreement. Any waiver must be in writing. The section headings in this Agreement are for convenience only and are not to be used in interpreting this Agreement.

i)Severability. To the extent that the terms set forth in this Agreement or any word, phrase, clause, or sentence is found to be illegal or unenforceable by a court of competent jurisdiction for any reason, such term, word, phrase, clause, or sentence will be modified in such manner so as to afford the Company the fullest protection commensurate with making this Agreement, as modified, legal and enforceable under applicable laws. If, however, a court of competent jurisdiction finds that any such term, word, phrase, clause, or sentence cannot be so modified and thus made enforceable, or otherwise declines for any reason to do so, such term, word, phrase, clause, or sentence will be deemed severed from this Agreement and of no force and effect, and the balance of this Agreement will not be affected thereby, the balance being construed as severable and independent.

j)Governing Law. The validity, interpretation, instruction, performance, enforcement, and remedies of or relating to this Agreement, and the rights and obligations of the parties hereunder, will be governed by and construed in accordance with the substantive internal laws of the State of Delaware, without regard to the conflict of law principles, rules, or statutes of any jurisdiction. The foregoing provisions of this subsection will apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may be governed by the laws of another jurisdiction (if any).

k)Venue and Jurisdiction. Venue for any legal proceedings instituted related to this Agreement will be exclusively in the state and/or federal courts located in Cook County, Illinois, and the Participant hereby knowingly, voluntarily, and irrevocably agrees, consents, and submits to the exclusive jurisdiction and venue of such courts within the State of Illinois. The Participant further hereby knowingly, voluntarily, and irrevocably waives, and agrees not to assert any objection, challenge, or defense to such exclusive venue or jurisdiction (including without limitation any defense of forum non conveniens), and further agrees not to file any claim or action related to this Agreement in any other jurisdiction or venue. The foregoing provisions of this Section 9.k) will apply irrespective of whether the Participant is a party to or bound by another restrictive covenant of any kind that may provide for or permit venue or jurisdiction with respect to such other restrictive covenant in any other court or forum (if any).

l)Notice. All notices given hereunder will be in writing and, if intended for the Company, will be addressed to it and mailed by registered mail, postage prepaid, or delivered to it at its principal office in Dublin, Ireland to the attention of the General Counsel or its principal office in Chicago,

Illinois to the attention of the Chief People Officer. If intended for the Participant, notices will be delivered personally or will be addressed (if sent by mail) to the Participant’s then current residence address as shown on the Company’s records, or to such other address as the Participant directs in a notice to the Company. All notices will be deemed to be given on the date received at the address of the addressee or, if delivered personally, on the date delivered.

m)Intellectual Property. The Participant acknowledges and agrees that the Company will own all rights in all discoveries, inventions, improvements, ideas, and designs, patentable or otherwise, trade secrets, confidential information, works of authorship, writings, and copyrightable material, which are conceived, developed, created, reduced to practice, or acquired by the Participant during the Participant’s employment and which relate to the business of the Company or any of its Affiliates or Subsidiaries or the actual or demonstrably anticipated research or development of Company or any of its Affiliates or Subsidiaries (collectively “Work Product”). All Work Product that is protectable by copyright is and will be a “work made for hire,” as that term is defined in the United States Copyright Act. To the extent Work Product is not a “work made for hire” as defined in the United States Copyright Act, Participant will and hereby does irrevocably assign to the Company the Participant’s entire right, title, and interest (including without limitation all copyrights and other intellectual property rights) in and to such Work Product together with any and all causes of actions including the rights of recovery for past infringements of Work Product. The Participant agrees to disclose promptly, fully, and in writing all Work Product to the Company. The Participant will, upon the Company’s request, execute, acknowledge, and deliver to the Company all instruments and do all other acts which are necessary or desirable to enable the Company or any of its Affiliates or Subsidiaries to file and prosecute applications for, and to acquire, maintain, and enforce, all patents, trademarks, and copyrights in all countries. To the extent the Participant is bound by an employee handbook or contract provision that protects the Company’s intellectual property at least to the extent provided in this Section 9.m), the provision set forth in such employment handbook or contractual arrangement between the Participant and the Company will prevail and govern.

n)Incentive Repayment Policies.

(i)Incentive Repayment Policy for Section 16 Officers. If the Participant is an officer for purposes of Section 16 of the Exchange Act, the Participant is subject to Aon’s Incentive Repayment Policy for Section 16 Officers (the “Officers Repayment Policy”). The Officers Repayment Policy provides that the Company will seek recoupment with respect to sale or all of the Award if (1) Aon plc is required to prepare an accounting restatement due to material noncompliance with any financial reporting requirement, (2) the amount of the Award is calculated based upon the achievement of financial results that were subsequently the subject of such a restatement, and (3) the amount received under the Award would have been lower if the financial results were properly reported. The Participant can obtain a copy of the Officers Repayment Policy from the Global Compensation team. If there is any conflict between this Agreement and the Officers Repayment Policy, such policy will control. If the Participant is subject to the Officers Repayment Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by such Policy.

(ii)Incentive Repayment Policy for Senior Executives (non-Section 16 Officers). If the Participant is member of the Aon Executive Committee (or any successor thereto) and not an officer of the Company for purposes of Section 16 of the Exchange Act, the Participant is subject to Aon’s Incentive Repayment Policy (For Senior Executives) (the

“Senior Executives Repayment Policy”).  The Senior Executives Repayment Policy provides that Aon plc may seek recoupment with respect to some or all of the Award if (1) Aon plc is required to prepare an accounting restatement due to material noncompliance with any financial reporting requirement, (2) the amount of the Award is calculated based upon the achievement of financial results that were subsequently the subject of such a restatement, and (3) the amount received under the Award would have been lower if the financial results were properly reported. The Participant can obtain a copy of the Senior Executives Repayment Policy from the Global Compensation team.  If there is any conflict between this Agreement and the Senior Executives Repayment Policy, such policy will control. If the Participant is subject to the Senior Executives Repayment Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by such policy.

(iii)Malus and Clawback. If the Participant is a Material Risk Taker of Aon Securities Limited or Aon Investments Limited, then the Award is subject to Aon’s Material Risk Takers Variable Pay Adjustment Policy (the “MRT Policy”). The MRT Policy provides that Aon will have the discretion to cancel, or require reimbursement of, all or part of the Award in certain circumstances. The Participant can obtain a copy of the MRT Policy from their HR business partner. If the Participant is subject to the MRT Policy, by accepting this Agreement, the Participant hereby agrees and acknowledges that the Participant will be bound by the MRT Policy including without limitation Aon’s discretion to cancel or require reimbursement of all or part of the Award in the circumstances set out within such policy.

o)Compliance with Law. Notwithstanding any other provision of the Plan or this Agreement, unless there is an available exemption from any registration, qualification, or other legal requirement applicable to the Shares, the Company will not be required to deliver any Shares issuable upon vesting/settlement of the RSUs prior to the completion of any registration or qualification of the Shares under any local, state, federal, or foreign securities or exchange control law or under rulings or regulations of the U.S. Securities and Exchange Commission (“SEC”) or of any other governmental regulatory body, or prior to obtaining any approval or other clearance from any local, state, federal, or foreign governmental agency, which registration, qualification or approval the Company will, in its absolute discretion, deem necessary or advisable. The Participant understands that the Company is under no obligation to register or qualify the Shares with the SEC or any state or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Shares. Further, the Participant agrees that the Company will have unilateral authority to amend the Plan and the Agreement without the Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Shares.

p)No Advice Regarding Grant. The Company is not providing any tax, legal, or financial advice, nor is the Company making any recommendations regarding the Participant’s participation in the Plan, or the acquisition or sale of the underlying Shares. The Participant should consult with the Participant’s own personal tax, legal, and financial advisors regarding the Participant’s participation in the Plan and execution of this Agreement, before executing this Agreement or otherwise taking any action at any time related to the Plan.

q)Appendices. Notwithstanding any provision of this Agreement to the contrary, if the Participant resides in a country outside the United States or is otherwise subject to the laws of a country other than the United States, the RSUs will be subject to the terms and conditions set forth in

Appendices A and C to this Agreement. In addition, the special terms and conditions in Appendix B will apply if the Participant permanently resides in (or is otherwise remunerated through the local payroll of) a country outside the United States. Moreover, if the Participant relocates to one of the countries included in Appendix C, the special terms and conditions for such country will apply to the Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. Appendices A through C constitute part of this Agreement.

r)Imposition of Other Requirements. The Company reserves the right to impose other requirements on the Participant’s participation in the Plan, on the RSUs, and on any Shares acquired under the Plan, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require the Participant to sign or accept any additional agreements or undertakings that may be necessary to accomplish the foregoing.

IN WITNESS WHEREOF, the parties have accepted this Agreement as of the date hereof.

AON PLC

________________________________

Gregory C. Case

Chief Executive Officer

________________________________________________    RSU Recipient (Participant)    Date

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 North America, Inc.	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 2.8% Senior Notes due 2030 6.25% Senior Notes due 2040	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	5.125% Senior Notes due 2027 5.150% Senior Notes due 2029 5.300% Senior Notes due 2031 5.450% Senior Notes due 2034 5.750% Senior Notes due 2054	2.85% Senior Notes due 2027 2.05% Senior Notes due 2031 2.60% Senior Notes due 2031 5.00% Senior Notes due 2032 5.35% Senior Notes due 2033 2.90% Senior Notes due 2051 3.90% Senior Notes due 2052
Aon plc	Ireland	Guarantor	Guarantor	Guarantor	Guarantor
Aon Global Limited	UK	Guarantor	Issuer	Guarantor	Guarantor
Aon Global Holdings plc	UK	Guarantor	Guarantor	Guarantor	Co-Issuer
Aon Corporation	US	Issuer	Guarantor	Guarantor	Co-Issuer
Aon North America, Inc.	US	Guarantor	Guarantor	Issuer	Guarantor

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 quarterly report on Form 10-Q 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.

Date:	April 26, 2024	/s/ GREGORY C. CASE
		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 quarterly report on Form 10-Q 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.

Date:	April 26, 2024	/s/ CHRISTA DAVIES
		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 Quarterly Report on Form 10-Q of the Company for the quarter ended March 31, 2024 (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

April 26, 2024

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 Quarterly Report on Form 10-Q of the Company for the quarter ended March 31, 2024 (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

April 26, 2024

XML

Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 25, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
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
Country Region	353
City Area Code	1
Local Phone Number	266 6000
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		217,430,759
Entity Central Index Key	0000315293
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
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 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 North America, Inc.’s 5.125% Senior Notes due 2027
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon North America, Inc.’s 5.125% Senior Notes due 2027
Trading Symbol	AON27B
Security Exchange Name	NYSE
Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon North America, Inc.’s 5.150% Senior Notes due 2029
Trading Symbol	AON29
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 North America, Inc.’s 5.300% Senior Notes due 2031
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon North America, Inc.’s 5.300% Senior Notes due 2031
Trading Symbol	AON31B
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 Corporation and Aon Global Holdings plc’s 5.35% Senior Notes due 2033
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.35% Senior Notes due 2033
Trading Symbol	AON33
Security Exchange Name	NYSE
Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon North America, Inc.’s 5.450% Senior Notes due 2034
Trading Symbol	AON34
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
Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054
Entity Information [Line Items]
Title of 12(b) Security	Guarantees of Aon North America, Inc.’s 5.750% Senior Notes due 2054
Trading Symbol	AON54
Security Exchange Name	NYSE

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Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue
Total revenue	$ 4,070	$ 3,871
Expenses
Compensation and benefits	1,883	1,792
Information technology	124	139
Premises	71	75
Depreciation of fixed assets	44	38
Amortization and impairment of intangible assets	16	25
Other general expense	348	329
Accelerating Aon United Program expenses	119	0
Total operating expenses	2,605	2,398
Operating income	1,465	1,473
Interest income	28	5
Interest expense	(144)	(111)
Other income (expense)	75	(25)
Income before income taxes	1,424	1,342
Income tax expense	331	263
Net income	1,093	1,079
Less: Net income attributable to noncontrolling interests	22	29
Net income attributable to Aon shareholders	$ 1,071	$ 1,050
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 5.38	$ 5.09
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 5.35	$ 5.07
Weighted average ordinary shares outstanding - basic (in shares)	199.1	206.1
Weighted average ordinary shares outstanding - diluted (in shares)	200.1	207.1

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Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 1,093	$ 1,079
Less: Net income attributable to noncontrolling interests	22	29
Net income attributable to Aon shareholders	1,071	1,050
Other comprehensive income, net of tax:
Change in fair value of financial instruments	75	3
Foreign currency translation adjustments	(132)	54
Postretirement benefit obligation	26	22
Total other comprehensive income (loss)	(31)	79
Less: Other comprehensive income attributable to noncontrolling interests	0	0
Total other comprehensive income (loss) attributable to Aon shareholders	(31)	79
Comprehensive income attributable to Aon shareholders	$ 1,040	$ 1,129

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Condensed Consolidated Statements of Financial Position - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 995	$ 778
Short-term investments	5,413	369
Receivables, net	4,035	3,254
Fiduciary assets	17,161	16,307
Other current assets	1,020	996
Total current assets	28,624	21,704
Goodwill	8,302	8,414
Intangible assets, net	217	234
Fixed assets, net	590	638
Operating lease right-of-use assets	628	650
Deferred tax assets	1,254	1,195
Prepaid pension	627	618
Other non-current assets	525	506
Total assets	40,767	33,959
Current liabilities
Accounts payable and accrued liabilities	1,925	2,262
Short-term debt and current portion of long-term debt	606	1,204
Fiduciary liabilities	17,161	16,307
Other current liabilities	2,146	1,878
Total current liabilities	21,838	21,651
Long-term debt	15,916	9,995
Non-current operating lease liabilities	611	641
Deferred tax liabilities	129	115
Pension, other postretirement, and postemployment liabilities	1,198	1,225
Other non-current liabilities	1,103	1,074
Total liabilities	40,795	34,701
Equity (deficit)
Ordinary shares - $0.01 nominal value Authorized: 500.0 shares (issued: 2024 - 198.6; 2023 - 198.6)	2	2
Additional paid-in capital	6,969	6,944
Accumulated deficit	(2,700)	(3,399)
Accumulated other comprehensive loss	(4,404)	(4,373)
Total Aon shareholders' deficit	(133)	(826)
Noncontrolling interests	105	84
Total deficit	(28)	(742)
Total liabilities and equity (deficit)	$ 40,767	$ 33,959

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Condensed Consolidated Statements of Financial Position (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
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)	198,600,000	198,600,000

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Condensed Consolidated Statements of Shareholders' Equity (Deficit) (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Ordinary Shares and Additional Paid-in Capital	Accumulated Deficit	Accumulated  Other Comprehensive Loss, Net of Tax	Non- controlling Interests
Beginning balance (in shares) at Dec. 31, 2022		205.4
Beginning balance at Dec. 31, 2022	$ (429)	$ 6,866	$ (2,772)	$ (4,623)	$ 100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,079		1,050		29
Shares issued - employee stock compensation plans (in shares)		0.9
Shares issued - employee stock compensation plans	(132)	$ (131)	(1)
Shares repurchased (in shares)		(1.8)
Shares repurchased	(550)		(550)
Share-based compensation expense	127	$ 127
Dividends to shareholders	(115)		(115)
Net change in fair value of financial instruments	3			3
Net foreign currency translation adjustments	54			54
Net postretirement benefit obligation	22			22
Dividends paid to noncontrolling interests on subsidiary common stock	(1)				(1)
Ending balance (in shares) at Mar. 31, 2023		204.5
Ending balance at Mar. 31, 2023	$ 58	$ 6,862	(2,388)	(4,544)	128
Beginning balance (in shares) at Dec. 31, 2023	198.6	198.6
Beginning balance at Dec. 31, 2023	$ (742)	$ 6,946	(3,399)	(4,373)	84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,093		1,071		22
Shares issued - employee stock compensation plans (in shares)		0.8
Shares issued - employee stock compensation plans	(104)	$ (104)
Shares repurchased (in shares)		(0.8)
Shares repurchased	(250)		(250)
Share-based compensation expense	130	$ 130
Dividends to shareholders	(122)		(122)
Net change in fair value of financial instruments	75			75
Net foreign currency translation adjustments	(132)			(132)
Net postretirement benefit obligation	26			26
Purchases of subsidiary shares from noncontrolling interests	(1)
Dividends paid to noncontrolling interests on subsidiary common stock	$ (1)				(1)
Ending balance (in shares) at Mar. 31, 2024	198.6	198.6
Ending balance at Mar. 31, 2024	$ (28)	$ 6,971	$ (2,700)	$ (4,404)	$ 105

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Condensed Consolidated Statements of Shareholders' Equity (Deficit) (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Stockholders' Equity [Abstract]
Dividends (in dollars per share)	$ 0.615	$ 0.56

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Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net income	$ 1,093	$ 1,079
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation of fixed assets	44	38
Amortization and impairment of intangible assets	16	25
Share-based compensation expense	130	127
Deferred income taxes	(76)	(70)
Other, net	(82)	0
Change in assets and liabilities:
Receivables, net	(826)	(664)
Accounts payable and accrued liabilities	(343)	(443)
Accelerating Aon United Program liabilities	34	0
Current income taxes	163	126
Pension, other postretirement and postemployment liabilities	(12)	(9)
Other assets and liabilities	168	234
Cash provided by operating activities	309	443
Cash flows from investing activities
Proceeds from investments	118	13
Purchases of investments	(56)	(11)
Net sales (purchases) of short-term investments - non fiduciary	(5,046)	280
Acquisition of businesses, net of cash and funds held on behalf of clients	(4)	(2)
Sale of businesses, net of cash and funds held on behalf of clients	75	1
Capital expenditures	(48)	(76)
Cash provided by (used for) investing activities	(4,961)	205
Cash flows from financing activities
Share repurchase	(250)	(550)
Proceeds from issuance of shares	25	25
Cash paid for employee taxes on withholding shares	(130)	(157)
Commercial paper issuances, net of repayments	(591)	(173)
Issuance of debt	5,942	744
Increase in fiduciary liabilities, net of fiduciary receivables	394	636
Cash dividends to shareholders	(123)	(115)
Noncontrolling interests and other financing activities	(6)	(6)
Cash provided by financing activities	5,261	404
Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients	(146)	58
Net increase in cash and cash equivalents and funds held on behalf of clients	463	1,110
Cash, cash equivalents and funds held on behalf of clients at beginning of period	7,722	7,076
Cash, cash equivalents and funds held on behalf of clients at end of period	8,185	8,186
Reconciliation of cash and cash equivalents and funds held on behalf of clients:
Cash and cash equivalents	995	1,119
Cash and cash equivalents and funds held on behalf of clients classified as held for sale	73	0
Funds held on behalf of clients	7,117	7,067
Total cash and cash equivalents and funds held on behalf of clients	8,185	8,186
Supplemental disclosures:
Interest paid	95	79
Income taxes paid, net of refunds	$ 244	$ 206

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Basis of Presentation

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying Condensed Consolidated Financial Statements and Notes thereto have been prepared in accordance with U.S. GAAP. The Condensed 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 Condensed 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.

Certain information and disclosures normally included in the Consolidated Financial Statements prepared in accordance with U.S. GAAP have been condensed or omitted. The Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of operating results that may be expected for the full year ending December 31, 2024.

Use of Estimates

The preparation of the accompanying Condensed 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 Condensed 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 Condensed Consolidated Financial Statements in future periods.

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Accounting Principles and Practices

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Accounting Principles and Practices

Accounting Principles and Practices

New Accounting Pronouncements

Accounting Standards Issued But Not Yet Adopted

Improvements to Reportable Segment Disclosures

In November 2023, the FASB issued new accounting guidance, requiring new segment disclosures under ASC 280, Segment Reporting, including disclosure of significant segment expense categories and amounts that are regularly reported to the CODM and included in the segment’s profit or loss. Additionally, all disclosure requirements under ASC 280, including new requirements under this new guidance, will be required on an interim basis. The new guidance is effective for Aon for the year ended December 31, 2024 and interim periods thereafter, with early adoption permitted. An entity will apply the new guidance on a retrospective basis for all periods presented. The Company is currently evaluating the impact the guidance will have on the Notes to Consolidated Financial Statements.

Improvements to Income Tax Disclosures

In December 2023, the FASB issued new accounting guidance under ASC 740, Income Taxes, which requires additional income tax disclosures on an annual basis, including disaggregation of information presented within the reconciliation of the expected tax to the reported tax by specific categories, with certain reconciling items 5% or greater broken out by nature and/or jurisdiction. The new guidance also requires disclosure of income taxes paid, net of refunds, broken out by federal, state/local, and foreign, including disclosure of individual jurisdictions when greater than 5% of total net income taxes paid. The new guidance is effective for Aon for the year ended December 31, 2025, with early adoption permitted. The Company is evaluating the period of adoption and transition approach, as well as the impact the disclosures will have on the Notes to Consolidated Financial Statements.

Securities and Exchange Commission Final Rules

The Enhancement and Standardization of Climate-Related Disclosures for Investors

In March 2024, the SEC adopted final rules to enhance and standardize climate-related disclosures. The final rules will require the Company to provide certain climate-related information in Item 7, Management’s Discussion and Analysis regarding material climate-related risks, activities to mitigate or adapt to such risks, information regarding oversight and management of climate-related risks, information on climate-related targets or goals, and disclosure of Scope 1 and 2 greenhouse gas (“GHG”) emissions. Additionally, within the Notes to Consolidated Financial Statements, the Company will be required to disclose the financial statement effects of severe weather events and other natural conditions. The final rules are effective for Aon for the year-ended December 31, 2025, with the exception of GHG emissions disclosures which are effective for Aon for the year-ended December 31, 2026. After the adoption of the final rules, the final rules became subject to several legal challenges, and on April 4, 2024 the SEC voluntarily stayed the final rules pending judicial review. The Company is currently evaluating the impact that the guidance will have on our disclosures and will monitor the judicial process for impacts on the disclosure requirements.

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Revenue from Contracts with Customers

3 Months Ended

Mar. 31, 2024

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):

	Three Months Ended March 31,
	2024		2023
Commercial Risk Solutions	$	1,808	$	1,778
Reinsurance Solutions	1,167		1,077
Health Solutions	733		671
Wealth Solutions	370		350
Eliminations	(8)		(5)
Total revenue	$	4,070	$	3,871

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):

	Three Months Ended March 31,
	2024		2023
United States	$	1,512	$	1,495
Americas other than United States	323		301
United Kingdom	583		554
Ireland	33		30
Europe, Middle East, & Africa other than United Kingdom and Ireland	1,209		1,102
Asia Pacific	410		389
Total revenue	$	4,070	$	3,871

Contract Costs

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	370	$	355
Additions	380		362
Amortization	(478)		(462)
Impairment	—		—
Foreign currency translation and other	(3)		2
Balance at end of period	$	269	$	257

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	195	$	185
Additions	14		10
Amortization	(13)		(12)
Impairment	—		—
Foreign currency translation and other	(2)		—
Balance at end of period	$	194	$	183

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Accelerating Aon United Program

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Accelerating Aon United Program

Accelerating Aon United Program

In the third quarter of 2023, Aon initiated a three-year restructuring program called the Accelerating Aon United Program (the “Program”) with the purpose of streamlining the Company’s technology infrastructure, optimizing its leadership structure and resource alignment, and reducing the real estate footprint to align to its hybrid working strategy. The Program will include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation and technology costs.

Program charges are recognized within Accelerating Aon United Program expenses on the accompanying Condensed Consolidated Statements of Income and consists of the following cost activities:

•Technology and other – includes costs associated with actions taken to rationalize certain applications and to optimize technology across the Company. These costs may include contract termination fees and other non-capitalizable costs associated with Program initiatives, which include professional service fees.

•Workforce optimization – includes costs associated with headcount reduction and other separation-related costs.

•Asset impairments – includes non-cash costs associated with impairment of assets, as they are identified, including ROU lease assets, leasehold improvements, and other capitalized assets no longer providing economic benefit.

The Program is currently expected to result in cumulative costs of approximately $1.0 billion, consisting of approximately $900 million of cash charges and approximately $100 million of non-cash charges. For the three months ended March 31, 2024, total Program costs incurred were $119 million. The Company expects to continue to review the implementation of elements of the Program throughout the course of the Program and, therefore, there may be changes to expected timing, estimates of expected costs, and related savings.

The Company’s unpaid liabilities for charges under the Program are generally included in Accounts payable and accrued liabilities in the Condensed Consolidated Statements of Financial Position.

The changes in the Company’s liabilities for the Program as of March 31, 2024 are as follows (in millions):

	Technology and other		Workforce optimization		Asset impairments		Total
Liability Balance as of January 1, 2024	$	14	$	86	$	—	$	100
Charges	19		64		36		119
Cash payments	(12)		(25)		—		(37)
Foreign currency translation and other	—		(1)		—		(1)
Non-cash charges	(7)		(5)		(36)		(48)
Liability balance as of March 31, 2024	$	14	$	119	$	—	$	133
Total costs incurred from inception to date	$	33	$	167	$	54	$	254

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Cash and Cash Equivalents and Short-Term Investments

3 Months Ended

Mar. 31, 2024

Cash, Cash Equivalents, and Short-Term Investments [Abstract]

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

At March 31, 2024, Cash and cash equivalents and Short-term investments were $6.4 billion compared to $1.1 billion at December 31, 2023, an increase of $5.3 billion primarily related to net proceeds from debt offerings to be used for general corporate purposes, including to fund the acquisition of NFP. Refer to Note 9 “Debt” for further information. Of the total balances, $112 million and $120 million were restricted as to their use at March 31, 2024 and December 31, 2023, respectively. Included within Short-term investments as of March 31, 2024 and December 31, 2023, were £55 million ($70 million at March 31, 2024 exchange rates) and £63 million ($80 million at December 31, 2023 exchange rates), respectively, 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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Other Financial Data

3 Months Ended

Mar. 31, 2024

Other Financial Data [Abstract]

Other Financial Data

Other Financial Data

Condensed Consolidated Statements of Income Information

Other Income (Expense)

Other income (expense) consists of the following (in millions):

	Three Months Ended March 31,
	2024		2023
Foreign currency remeasurement	4		(19)
Equity earnings	2		3
Pension and other postretirement	(10)		(17)
Financial instruments and other (1)	79		8
Total	$	75	$	(25)

(1)For the period ended March 31, 2024, an $82 million gain was recognized related to deferred consideration from the affiliates of The Blackstone Group L.P and the other designated purchasers related to a divestiture completed in a prior year period, refer to Note 7, “Acquisitions and Dispositions of Businesses” for additional information.

Condensed 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):

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	79	$	76
Provision	5		7
Accounts written off, net of recoveries	(2)		—
Foreign currency translation and other	(1)		—
Balance at end of period	$	81	$	83

Other Current Assets

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

As of	March 31, 2024		December 31, 2023
Assets held for sale (1)	$	446	$	354
Costs to fulfill contracts with customers (2)	269		370
Prepaid expenses	128		100
Taxes receivable	19		35
Other	158		137
Total	$	1,020	$	996

(1)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

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

Other Non-Current Assets

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

As of	March 31, 2024		December 31, 2023
Costs to obtain contracts with customers (1)	$	194	$	195
Taxes receivable	98		100
Investments	80		45
Leases	21		26
Other	132		140
Total	$	525	$	506

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

Other Current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable	$	397	$	291
Deferred revenue (1)	360		270
Leases	179		182
Liabilities held for sale (2)	129		69
Other	1,081		1,066
Total	$	2,146	$	1,878

(1)During the three months ended March 31, 2024, revenue of $179 million was recognized in the Condensed Consolidated Statements of Income. During the three months ended March 31, 2023, revenue of $167 million was recognized in the Condensed Consolidated Statements of Income.

(2)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

Other Non-Current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable (1)	$	866	$	827
Compensation and benefits	55		59
Deferred revenue	31		33
Leases	5		10
Other	146		145
Total	$	1,103	$	1,074

(1)Includes $72 million for the non-current portion of the one-time mandatory transition tax on accumulated foreign earnings as of March 31, 2024 and December 31, 2023

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Acquisitions and Dispositions of Businesses

3 Months Ended

Mar. 31, 2024

Business Combination and Asset Acquisition [Abstract]

Acquisitions and Dispositions of Businesses

Acquisitions and Dispositions of Businesses

Completed Acquisitions

The Company completed no acquisitions during the three months ended March 31, 2024 and no acquisitions during the three months ended March 31, 2023.

2023 Acquisitions

On November 30, 2023, the Company completed the acquisition of 100% of the share capital of Gi&Bi S.r.l., an Italy-based insurance broker specialized in the agricultural business segment.

On August 30, 2023, the Company completed the acquisition of 100% of the share capital of NGS (Uruguay) S.A., a risk management consultant firm in Uruguay.

On June 22, 2023, the Company completed the acquisition of 100% of the share capital of Benefits Corredores de Seguros and Asesorías e Inversiones Benefits, a business that provides health and benefits brokerage and benefit administration in Chile.

Completed Dispositions

The Company completed one disposition during the three months ended March 31, 2024 and no dispositions during the three months ended March 31, 2023.

There were no pretax gains recognized related to dispositions for the three months ended March 31, 2024 or 2023, respectively. Gains recognized as a result of a disposition are included in Other income (expense) in the Condensed Consolidated Statements of Income. There were no losses recognized for the three months ended March 31, 2024 or 2023, respectively.

Assets and Liabilities Held for Sale

As of March 31, 2024, Aon classified certain assets and liabilities as held for sale, as the Company has committed to a plan to sell the assets and liabilities within one year. Total assets and liabilities, for disposal groups classified as held for sale within

Other current assets and Other current liabilities in the Condensed Consolidated Statements of Financial Position were $446 million and $129 million, respectively. Of the $446 million total assets classified as held for sale, $156 million relate to intangible assets.

Other Significant Activity

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”) and certain designated purchases that are direct or indirect subsidiaries of the Buyer. The Buyer purchased all of the outstanding equity interests of the Divested Business, plus certain related assets and liabilities for a purchase price of $4.3 billion in cash paid at closing and deferred consideration of up to $500 million. In the first quarter of 2024, the Company earned $82 million of deferred consideration from the Buyer and the other designated purchasers.

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Goodwill and Other Intangible Assets

3 Months Ended

Mar. 31, 2024

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 three months ended March 31, 2024 are as follows (in millions):

Balance as of December 31, 2023	$	8,414
Foreign currency translation and other	(112)
Balance as of March 31, 2024	$	8,302

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

	March 31, 2024						December 31, 2023
	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	$	1,857	$	1,683	$	174	$	1,873	$	1,686	$	187
Technology and other	367		324		43		371		324		47
Total	$	2,224	$	2,007	$	217	$	2,244	$	2,010	$	234

The estimated future amortization for finite-lived intangible assets as of March 31, 2024 is as follows (in millions):

Remainder of 2024	$	52
2025	55
2026	34
2027	22
2028	17
2029	12
Thereafter	25
Total	$	217

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Debt

3 Months Ended

Mar. 31, 2024

Debt Disclosure [Abstract]

Debt

Debt

Notes

On March 1, 2024, Aon North America, Inc. issued $600 million 5.125% Senior Notes due in March 2027, $1 billion 5.150% Senior Notes due in March 2029, $650 million 5.300% Senior Notes due in March 2031, $1.75 billion 5.450% Senior Notes due in March 2034, and $2 billion 5.750% Senior Notes due in March 2054, totaling to an aggregate amount of $6 billion. The Company intends to use the net proceeds from the offering for general corporate purposes, including a portion of which that was used, together with the proceeds of the delayed draw term loan available under the credit agreement entered into on February 16, 2024 described below, to pay a portion of the cash consideration in connection with the acquisition of NFP, to repay certain debt of NFP and to pay related fees and expenses.

On February 16, 2024, Aon North America, Inc. entered into a credit agreement in which lenders committed to provide a $2 billion delayed draw term loan, which was subsequently drawn on April 25, 2024. The Company intends to use proceeds, together with the proceeds of the notes issued on March 1, 2024 described above, to pay a portion of the cash consideration in connection with the NFP acquisition, to repay certain debt of NFP and to pay related fees and expenses.

In November 2023, Aon Global Limited’s $350 million 4.00% Senior Notes matured and were repaid in full.

In June 2023, Aon Global Limited’s $600 million 3.50% Senior Notes due June 2024 were classified as Short-term debt and current portion of long-term debt in the Condensed Consolidated Statement of Financial Position as the date of maturity is in less than one year.

On February 28, 2023, 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 $750 million 5.35% Senior Notes due in February 2033. The Company intends to use the net proceeds from the offering for general corporate purposes.

Revolving Credit Facilities

As of March 31, 2024, Aon had two primary committed credit facilities outstanding: its $1.0 billion multi-currency U.S. credit facility expiring in September 2027 and its $1.0 billion multi-currency U.S. credit facility expiring in October 2028. In aggregate, these two facilities provide $2.0 billion in available credit.

Each of these primary committed credit facilities and the delayed draw term loan 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. Aon did not have borrowings under either of these primary committed credit facilities nor the delayed draw term loan as of March 31, 2024 and December 31, 2023, respectively. Additionally, Aon was in compliance with the financial covenants and all other covenants contained therein during the rolling 12 months ended March 31, 2024.

Commercial Paper

Aon Corporation has established a U.S. commercial paper program (the “U.S. Program”) and Aon Global Holdings plc has established a European multi-currency commercial paper program (the “European Program” and, together with the U.S. Program, the “Commercial Paper Program”). Commercial paper may be issued in aggregate principal amounts of up to approximately $1.3 billion under the U.S. Program and €625 million ($677 million at March 31, 2024 exchange rates) under the European Program, not to exceed the amount of the Company’s committed credit facilities, which was $2.0 billion at March 31, 2024. 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, Aon North America, Inc., and Aon Global Holdings plc and the European Program was fully and unconditionally guaranteed by Aon plc, Aon Global Limited, Aon North America, Inc., and Aon Corporation.

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

	March 31, 2024		December 31, 2023
Commercial paper outstanding	$	—	$	597

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

	Three Months Ended March 31,
	2024			2023
Weighted average commercial paper outstanding	$	381		$	393
Weighted average interest rate of commercial paper outstanding	5.65		%	3.38		%

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Income Taxes

3 Months Ended

Mar. 31, 2024

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

The effective tax rate on Net income was 23.2% for the three months ended March 31, 2024. The effective tax rate on Net income was 19.6% for the three months ended March 31, 2023.

For the three months ended March 31, 2024, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, including the favorable impact of share-based payments offset by the unfavorable impact of discrete items.

For the three months ended March 31, 2023, the tax rate was primarily driven by the geographical distribution of income and certain discrete items, primarily the favorable impacts of share-based payments.

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Shareholders' Equity (Deficit)

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Shareholders' Equity (Deficit)

Shareholders’ Equity (Deficit)

Ordinary Shares

Aon has a share repurchase program authorized by the Company’s Board of Directors (“the Repurchase Program”). 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):

	Three Months Ended March 31,
	2024		2023
Shares repurchased	0.8		1.8
Average price per share	$	310.56	$	305.31
Repurchase costs recorded to accumulated deficit	$	250	$	550

At March 31, 2024, the remaining authorized amount for share repurchases under the Repurchase Program was approximately $3.1 billion. Under the Repurchase Program, the Company has repurchased a total of 169.9 million shares for an aggregate cost of approximately $24.4 billion.

Weighted Average Ordinary Shares

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

	Three Months Ended March 31,
	2024	2023
Basic weighted average ordinary shares outstanding	199.1	206.1
Dilutive effect of potentially issuable shares	1.0	1.0
Diluted weighted average ordinary shares outstanding	200.1	207.1

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 0.1 million shares excluded from the calculation for the three months ended March 31, 2024 and no shares excluded from the calculation for the three months ended March 31, 2023.

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, 2023	$	2	$	(1,584)	$	(2,791)	$	(4,373)
Other comprehensive income (loss) before reclassifications, net	72		(132)		—		(60)
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	4		—		35		39
Tax expense	(1)		—		(9)		(10)
Amounts reclassified from accumulated other comprehensive income, net	3		—		26		29
Net current period other comprehensive income (loss)	75		(132)		26		(31)
Balance at March 31, 2024	$	77	$	(1,716)	$	(2,765)	$	(4,404)

	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)
Other comprehensive income (loss) before reclassifications, net	—		54		(1)		53
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	5		—		32		37
Tax expense	(2)		—		(9)		(11)
Amounts reclassified from accumulated other comprehensive income, net	3		—		23		26
Net current period other comprehensive income (loss)	3		54		22		79
Balance at March 31, 2023	$	(8)	$	(1,807)	$	(2,729)	$	(4,544)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Condensed 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 Condensed Consolidated Statements of Income.

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Employee Benefits

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Employee Benefits

Employee Benefits

The following table provides the components of the net periodic (benefit) cost recognized in the Condensed Consolidated Statements of Income for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	Three Months Ended March 31,
	U.K.				U.S.				Other
	2024		2023		2024		2023		2024		2023
Service cost	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	35		36		23		26		9		10
Expected return on plan assets, net of administration expenses	(47)		(46)		(33)		(30)		(13)		(12)
Amortization of prior-service cost	1		—		—		—		—		—
Amortization of net actuarial loss	20		18		7		9		3		3
Net periodic (benefit) cost	9		8		(3)		5		(1)		1
Loss on pension settlement	—		—		—		—		—		—
Total net periodic (benefit) cost	$	9	$	8	$	(3)	$	5	$	(1)	$	1

Contributions

Assuming no additional contributions are agreed to with, or required by, the pension plan trustees, the Company expects to make total cash contributions of approximately $2 million, $53 million, and $13 million (at December 31, 2023 exchange rates) to its significant U.K., U.S., and other major pension plans, respectively, during 2024. The following table summarizes contributions made to the Company’s significant pension plans (in millions):

	Three Months Ended March 31,
	2024		2023
Contributions to U.K. pension plans	$	1	$	1
Contributions to U.S. pension plans	14		16
Contributions to other major pension plans	2		6
Total contributions	$	17	$	23

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Derivatives and Hedging

3 Months Ended

Mar. 31, 2024

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives and Hedging

Derivatives and Hedging

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

Foreign Exchange Risk Management

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

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

	Notional Amount				Net Amount of Derivative Assets  Presented in the Statements of Financial Position (1)				Net Amount of Derivative Liabilities  Presented in the Statements of Financial Position (2)
	March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023
Foreign exchange contracts
Accounted for as hedges	$	736	$	1,724	$	36	$	34	$	—	$	2
Not accounted for as hedges (3)	459		382		1		2		—		1
Total	$	1,195	$	2,106	$	37	$	36	$	—	$	3

(1)Included within Other current assets ($19 million at March 31, 2024 and $17 million at December 31, 2023) or Other non-current assets ($18 million at March 31, 2024 and $19 million at December 31, 2023).

(2)Included within Other current liabilities ($3 million at December 31, 2023).

(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 recognized in the Condensed Consolidated Financial Statements are as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Gain recognized in Accumulated other comprehensive loss	$	97	$	—

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

	Three Months Ended March 31,
	2024		2023
Losses recognized in Total revenue	$	(4)	$	(5)

The Company estimates that approximately $2 million of pretax gains currently included within Accumulated other comprehensive loss will be reclassified into earnings in the next twelve months.

During the three months ended March 31, 2024 and March 31, 2023, the Company recorded a loss of $3 million and gain of $9 million, respectively, in Other income (expense) for foreign exchange derivatives not designated or qualifying as hedges.

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Fair Value Measurements and Financial Instruments

3 Months Ended

Mar. 31, 2024

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:

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.

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 Condensed 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.

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 March 31, 2024 and December 31, 2023 (in millions):

			Fair Value Measurements Using
	Balance at March 31, 2024		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)	$	8,236	$	8,236	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	58	$	—	$	58	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	22	$	—	$	22	$	—

			Fair Value Measurements Using
	Balance at December 31, 2023		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)	$	3,204	$	3,204	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	49	$	—	$	49	$	—
Liabilities					0
Derivatives (2)
Gross foreign exchange contracts	$	16	$	—	$	16	$	—

(1)Included within Fiduciary assets or Short-term investments in the Condensed 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 in the three months ended March 31, 2024 or 2023. The Company recognized no realized or unrealized gains or losses in the Condensed Consolidated Statements of Income during the three months ended March 31, 2024 or 2023 related to assets and liabilities measured at fair value using unobservable inputs.

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):

	March 31, 2024				December 31, 2023
	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	600	$	598	$	600	$	595
Long-term debt	$	15,916	$	15,151	$	9,995	$	9,223

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Claims, Lawsuits, and Other Contingencies

3 Months Ended

Mar. 31, 2024

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, including coverage from Aon’s self-insurance program. Accruals for these exposures, and related insurance receivables, when applicable, are included in the Condensed Consolidated Statements of Financial Position and have been recognized in Other general expense in the Condensed 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’s contingencies and exposures are subject to significant uncertainties, and the determination of likelihood of a loss and estimating any such loss can be complex. The Company is therefore, in certain matters, unable to estimate the range of reasonably possible loss. 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. Certain significant legal proceedings involving us or our subsidiaries are described below.

Current Matters

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 ($37 million at March 31, 2024 exchange rates). In February 2024, the claim brought by representatives of 16 passengers in the High Court in England was dismissed pursuant to an agreement among the parties. 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.

Certain of the Company’s clients and counterparties have initiated or indicated that they may initiate legal proceedings against the Company following allegations in July 2023 that fraudulent letters of credit were issued in the name of third-party banks in connection with transactions for which capital was arranged by Vesttoo Ltd. (“Vesttoo”). Vesttoo is one of the third parties that identifies capital providers to collateralize insurance and reinsurance obligations of the Company’s clients and counterparties. In certain transactions in which Vesttoo identified third party capital providers to collateralize reinsurance obligations, including transactions in which the Company or its affiliates provided brokerage or other services, some letters of credit from third party banks are alleged to have been fraudulent. The pending or threatened legal proceedings against the Company allege, among other theories of liability, that in certain circumstances the Company failed to comply with its alleged duty to procure appropriate letters of credit. In particular, on November 30, 2023, Clear Blue Insurance Company and certain of its affiliates filed a lawsuit in New York State Supreme Court against Aon plc and Aon Insurance Managers (Bermuda) Ltd. alleging such claims. While Aon has settled and/or is in discussions to settle certain claims, Aon believes that it has meritorious defenses and intends to vigorously defend itself against those claims that are not settled. In the fourth quarter of 2023, the Company recognized actual or anticipated legal settlement expenses in connection with these matters of $197 million, of which a potentially significant amount may be recoverable in future periods. Aon may also seek recourse against third parties where appropriate, including in connection with bankruptcy proceedings filed by Vesttoo in the Bankruptcy Court for the U.S. District of Delaware. In addition, in August 2023, joint provisional liquidators were appointed over one of the Company’s subsidiaries in Bermuda with respect to segregated accounts that were impacted by the allegedly fraudulent letters of credit. Aon continues to cooperate with regulators in Bermuda, and other regulatory authorities could initiate investigations or proceedings against the Company or third parties.

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 Condensed Consolidated 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

On June 22, 2023, Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon Corporation, and Aon North America, Inc., and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”), as applicable, entered into supplemental indentures, each dated June 22, 2023, amending each of the following indentures (as amended, supplemented or modified from time to time) to add for the benefit of the holders of the instruments issued thereunder a full and unconditional guarantee of Aon North America, Inc. thereunder: (i) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the Indenture, dated January 13, 1997); (ii) Second Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated April 2, 2012, amending and restating the

Indenture, dated September 10, 2010); (iii) Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 12, 2012); (iv) Second Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Amended and Restated Indenture, dated May 20, 2015, amending and restating the Indenture, dated May 24, 2013); (v) Amended and Restated Indenture, dated April 1, 2020, among Aon plc, Aon Corporation, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated November 13, 2015); and (vi) Amended and Restated Indenture, dated April 1, 2020, among Aon Corporation, Aon plc, Aon Global Limited, Aon Global Holdings plc and the Trustee (amending and restating the Indenture, dated December 3, 2018).

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 $139 million at March 31, 2024, and $86 million at December 31, 2023. These LOCs cover the beneficiaries related to certain of Aon’s U.S. and Canadian secure non-qualified pension plan schemes, reinsurance obligations related to Aon’s own E&O liability insurance program, 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 $110 million at March 31, 2024 compared to $194 million at December 31, 2023.

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Segment Information

3 Months Ended

Mar. 31, 2024

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 and Human Capital Solutions through four solution lines — Commercial risk, Reinsurance, Health, and Wealth, 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 Condensed Consolidated Statements of Income. Refer to Note 3 “Revenue from Contracts with Customers” for further information on revenue by principal service line.

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Subsequent Events

3 Months Ended

Mar. 31, 2024

Subsequent Events [Abstract]

Subsequent Events

Subsequent Events

NFP Acquisition

On April 25, 2024, the Company completed its acquisition of NFP, a leading middle-market provider of property and casualty brokerage, benefits consulting, wealth management, and retirement plan consulting, with more than 7,700 colleagues. The Company acquired NFP Intermediate Holdings A Corp. in a cash-and-stock merger for an aggregate preliminary purchase price totaling $9.1 billion, with approximately $3.2 billion to settle NFP indebtedness and cash consideration to the selling shareholders, and approximately 19 million class A ordinary shares with a fair value of approximately $5.9 billion. The initial accounting for the acquisition is incomplete as of the date of this Form 10-Q, as the information necessary to complete such evaluations was not practicable due to the timing of acquisition closing. We have not yet determined the purchase price allocation, including the fair value of the acquisition. The preliminary accounting impact of this acquisition will be included in our Condensed Consolidated Financial Statements beginning in the second quarter of 2024.

Debt Activity

On April 2, 2024, Aon plc announced that its wholly owned subsidiary, Randolph Acquisition Corp., commenced cash tender offers for any and all of the outstanding 6.875% Senior Notes due 2028, 4.875% Senior Secured Notes due 2028, 7.500% Senior Secured Notes due 2030 and 8.500% Senior Secured Notes due 2031, each issued by NFP Corp. (together, the “NFP Notes”), upon the terms and subject to the conditions set forth in the Offer to Purchase and Consent Solicitation Statement,

dated as of April 2, 2024. On April 26, 2024, the Offeror purchased those NFP Notes that were validly tendered and not validly withdrawn prior to April 15, 2024, effecting the early settlement of the Offers (the “Early Settlement”). In addition, on April 16, 2024, NFP Corp. delivered notices of redemption of all NFP Notes not validly tendered pursuant to the Offers and purchased at the Early Settlement, at a purchase price equal to the price paid to holders of the NFP Notes in connection with the Early Settlement, with a redemption date of April 26, 2024. As a result of the Early Settlement of the Offers and the related redemption which occurred on April 26, 2024, no NFP Notes remain outstanding.

Disposition of Business

On April 20, 2024, Aon signed a definitive agreement to sell Healthy Paws, its U.S.-based managing general agent specializing in pet insurance, to Chubb Limited. Assets and liabilities associated with this disposal group were classified as held for sale as of March 31, 2024. The disposition is expected to be completed in the second quarter of 2024.

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Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 1,071	$ 1,050

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Insider Trading Arrangements

3 Months Ended

Mar. 31, 2024

shares

Trading Arrangements, by Individual

Non-Rule 10b5-1 Arrangement Adopted

false

Rule 10b5-1 Arrangement Terminated

false

Non-Rule 10b5-1 Arrangement Terminated

false

Darren Zeidel [Member]

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

On March 8, 2024, Darren Zeidel, Executive Vice President, General Counsel and Company Secretary of the Company, adopted a new Rule 10b5-1 trading plan. The plan’s maximum length is until December 31, 2024 and first trades will not occur until June 7, 2024, at the earliest. The plan is intended to permit Mr. Zeidel to sell 3,299 and 3,298 class A ordinary shares of Aon in two separate transactions.

Name

Darren Zeidel

Title

Executive Vice President, General Counsel and Company Secretary

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

March 8, 2024

Arrangement Duration

298 days

Transaction One [Member] | Darren Zeidel [Member]

Trading Arrangements, by Individual

Aggregate Available

3,299

Transaction Two [Member] | Darren Zeidel [Member]

Trading Arrangements, by Individual

Aggregate Available

3,298

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Accounting Principles and Practices (Policies)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying Condensed Consolidated Financial Statements and Notes thereto have been prepared in accordance with U.S. GAAP. The Condensed 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 Condensed 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.

Certain information and disclosures normally included in the Consolidated Financial Statements prepared in accordance with U.S. GAAP have been condensed or omitted. The Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of operating results that may be expected for the full year ending December 31, 2024.

Use of Estimates

Use of Estimates

The preparation of the accompanying Condensed 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 Condensed 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 Condensed Consolidated Financial Statements in future periods.

Derivatives and Hedging

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

Foreign Exchange Risk Management

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

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:

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.

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 Condensed 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.

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

Accounting Standards Issued But Not Yet Adopted

Improvements to Reportable Segment Disclosures

In November 2023, the FASB issued new accounting guidance, requiring new segment disclosures under ASC 280, Segment Reporting, including disclosure of significant segment expense categories and amounts that are regularly reported to the CODM and included in the segment’s profit or loss. Additionally, all disclosure requirements under ASC 280, including new requirements under this new guidance, will be required on an interim basis. The new guidance is effective for Aon for the year ended December 31, 2024 and interim periods thereafter, with early adoption permitted. An entity will apply the new guidance on a retrospective basis for all periods presented. The Company is currently evaluating the impact the guidance will have on the Notes to Consolidated Financial Statements.

Improvements to Income Tax Disclosures

In December 2023, the FASB issued new accounting guidance under ASC 740, Income Taxes, which requires additional income tax disclosures on an annual basis, including disaggregation of information presented within the reconciliation of the expected tax to the reported tax by specific categories, with certain reconciling items 5% or greater broken out by nature and/or jurisdiction. The new guidance also requires disclosure of income taxes paid, net of refunds, broken out by federal, state/local, and foreign, including disclosure of individual jurisdictions when greater than 5% of total net income taxes paid. The new guidance is effective for Aon for the year ended December 31, 2025, with early adoption permitted. The Company is evaluating the period of adoption and transition approach, as well as the impact the disclosures will have on the Notes to Consolidated Financial Statements.

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Revenue from Contracts with Customers (Tables)

3 Months Ended

Mar. 31, 2024

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions):

	Three Months Ended March 31,
	2024		2023
Commercial Risk Solutions	$	1,808	$	1,778
Reinsurance Solutions	1,167		1,077
Health Solutions	733		671
Wealth Solutions	370		350
Eliminations	(8)		(5)
Total revenue	$	4,070	$	3,871

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):

	Three Months Ended March 31,
	2024		2023
United States	$	1,512	$	1,495
Americas other than United States	323		301
United Kingdom	583		554
Ireland	33		30
Europe, Middle East, & Africa other than United Kingdom and Ireland	1,209		1,102
Asia Pacific	410		389
Total revenue	$	4,070	$	3,871

Schedule of Capitalized Contract Cost

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	370	$	355
Additions	380		362
Amortization	(478)		(462)
Impairment	—		—
Foreign currency translation and other	(3)		2
Balance at end of period	$	269	$	257

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	195	$	185
Additions	14		10
Amortization	(13)		(12)
Impairment	—		—
Foreign currency translation and other	(2)		—
Balance at end of period	$	194	$	183

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Restructuring and Related Activities (Tables)

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Summary of Restructuring Liabilities for the Program

The changes in the Company’s liabilities for the Program as of March 31, 2024 are as follows (in millions):

	Technology and other		Workforce optimization		Asset impairments		Total
Liability Balance as of January 1, 2024	$	14	$	86	$	—	$	100
Charges	19		64		36		119
Cash payments	(12)		(25)		—		(37)
Foreign currency translation and other	—		(1)		—		(1)
Non-cash charges	(7)		(5)		(36)		(48)
Liability balance as of March 31, 2024	$	14	$	119	$	—	$	133
Total costs incurred from inception to date	$	33	$	167	$	54	$	254

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Other Financial Data (Tables)

3 Months Ended

Mar. 31, 2024

Other Financial Data [Abstract]

Schedule of Other Income (Expense)

Other income (expense) consists of the following (in millions):

	Three Months Ended March 31,
	2024		2023
Foreign currency remeasurement	4		(19)
Equity earnings	2		3
Pension and other postretirement	(10)		(17)
Financial instruments and other (1)	79		8
Total	$	75	$	(25)

(1)For the period ended March 31, 2024, an $82 million gain was recognized related to deferred consideration from the affiliates of The Blackstone Group L.P and the other designated purchasers related to a divestiture completed in a prior year period, refer to Note 7, “Acquisitions and Dispositions of Businesses” for additional information.

Schedule of Allowance for Doubtful Accounts

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

	Three Months Ended March 31,
	2024		2023
Balance at beginning of period	$	79	$	76
Provision	5		7
Accounts written off, net of recoveries	(2)		—
Foreign currency translation and other	(1)		—
Balance at end of period	$	81	$	83

Schedule of Other Current Assets

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

As of	March 31, 2024		December 31, 2023
Assets held for sale (1)	$	446	$	354
Costs to fulfill contracts with customers (2)	269		370
Prepaid expenses	128		100
Taxes receivable	19		35
Other	158		137
Total	$	1,020	$	996

(1)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

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

Schedule of Other Non-current Assets

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

As of	March 31, 2024		December 31, 2023
Costs to obtain contracts with customers (1)	$	194	$	195
Taxes receivable	98		100
Investments	80		45
Leases	21		26
Other	132		140
Total	$	525	$	506

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

Schedule of Other Current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable	$	397	$	291
Deferred revenue (1)	360		270
Leases	179		182
Liabilities held for sale (2)	129		69
Other	1,081		1,066
Total	$	2,146	$	1,878

(1)During the three months ended March 31, 2024, revenue of $179 million was recognized in the Condensed Consolidated Statements of Income. During the three months ended March 31, 2023, revenue of $167 million was recognized in the Condensed Consolidated Statements of Income.

(2)Refer to Note 7 “Acquisitions and Dispositions of Businesses” for further information.

Schedule of Other Non-current Liabilities

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

As of	March 31, 2024		December 31, 2023
Taxes payable (1)	$	866	$	827
Compensation and benefits	55		59
Deferred revenue	31		33
Leases	5		10
Other	146		145
Total	$	1,103	$	1,074

(1)Includes $72 million for the non-current portion of the one-time mandatory transition tax on accumulated foreign earnings as of March 31, 2024 and December 31, 2023

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Goodwill and Other Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2024

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 three months ended March 31, 2024 are as follows (in millions):

Balance as of December 31, 2023	$	8,414
Foreign currency translation and other	(112)
Balance as of March 31, 2024	$	8,302

Schedule of Other Intangible Assets by Asset Class

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

	March 31, 2024						December 31, 2023
	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	$	1,857	$	1,683	$	174	$	1,873	$	1,686	$	187
Technology and other	367		324		43		371		324		47
Total	$	2,224	$	2,007	$	217	$	2,244	$	2,010	$	234

Schedule of Estimated Future Amortization Expense on Intangible Assets

The estimated future amortization for finite-lived intangible assets as of March 31, 2024 is as follows (in millions):

Remainder of 2024	$	52
2025	55
2026	34
2027	22
2028	17
2029	12
Thereafter	25
Total	$	217

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Debt (Tables)

3 Months Ended

Mar. 31, 2024

Debt Disclosure [Abstract]

Schedule of Commercial Paper Outstanding

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

	March 31, 2024		December 31, 2023
Commercial paper outstanding	$	—	$	597

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

	Three Months Ended March 31,
	2024			2023
Weighted average commercial paper outstanding	$	381		$	393
Weighted average interest rate of commercial paper outstanding	5.65		%	3.38		%

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Shareholders' Equity (Deficit) (Tables)

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Schedule of Share Repurchase Activity

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

	Three Months Ended March 31,
	2024		2023
Shares repurchased	0.8		1.8
Average price per share	$	310.56	$	305.31
Repurchase costs recorded to accumulated deficit	$	250	$	550

Schedule of Components of Weighted Average Number of Shares Outstanding

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

	Three Months Ended March 31,
	2024	2023
Basic weighted average ordinary shares outstanding	199.1	206.1
Dilutive effect of potentially issuable shares	1.0	1.0
Diluted weighted average ordinary shares outstanding	200.1	207.1

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, 2023	$	2	$	(1,584)	$	(2,791)	$	(4,373)
Other comprehensive income (loss) before reclassifications, net	72		(132)		—		(60)
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	4		—		35		39
Tax expense	(1)		—		(9)		(10)
Amounts reclassified from accumulated other comprehensive income, net	3		—		26		29
Net current period other comprehensive income (loss)	75		(132)		26		(31)
Balance at March 31, 2024	$	77	$	(1,716)	$	(2,765)	$	(4,404)

	Change in Fair Value of Financial Instruments (1)		Foreign Currency Translation Adjustments		Postretirement Benefit Obligation (2)		Total
Balance at December 31, 2022	$	(11)	$	(1,861)	$	(2,751)	$	(4,623)
Other comprehensive income (loss) before reclassifications, net	—		54		(1)		53
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	5		—		32		37
Tax expense	(2)		—		(9)		(11)
Amounts reclassified from accumulated other comprehensive income, net	3		—		23		26
Net current period other comprehensive income (loss)	3		54		22		79
Balance at March 31, 2023	$	(8)	$	(1,807)	$	(2,729)	$	(4,544)

(1)Reclassifications from this category included in Accumulated other comprehensive loss are recorded in Total revenue, Interest expense, and Compensation and benefits in the Condensed 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 Condensed Consolidated Statements of Income.

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Employee Benefits (Tables)

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Schedule of Components of Net Periodic Benefit Cost for the Pension Plans

The following table provides the components of the net periodic (benefit) cost recognized in the Condensed Consolidated Statements of Income for Aon’s significant U.K., U.S., and other major pension plans, which are located in the Netherlands and Canada. Service cost is reported in Compensation and benefits and all other components are reported in Other income (expense) as follows (in millions):

	Three Months Ended March 31,
	U.K.				U.S.				Other
	2024		2023		2024		2023		2024		2023
Service cost	$	—	$	—	$	—	$	—	$	—	$	—
Interest cost	35		36		23		26		9		10
Expected return on plan assets, net of administration expenses	(47)		(46)		(33)		(30)		(13)		(12)
Amortization of prior-service cost	1		—		—		—		—		—
Amortization of net actuarial loss	20		18		7		9		3		3
Net periodic (benefit) cost	9		8		(3)		5		(1)		1
Loss on pension settlement	—		—		—		—		—		—
Total net periodic (benefit) cost	$	9	$	8	$	(3)	$	5	$	(1)	$	1

Schedule of Employer's Contributions

The following table summarizes contributions made to the Company’s significant pension plans (in millions):

	Three Months Ended March 31,
	2024		2023
Contributions to U.K. pension plans	$	1	$	1
Contributions to U.S. pension plans	14		16
Contributions to other major pension plans	2		6
Total contributions	$	17	$	23

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Derivatives and Hedging (Tables)

3 Months Ended

Mar. 31, 2024

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 (2)
	March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023		March 31, 2024		December 31, 2023
Foreign exchange contracts
Accounted for as hedges	$	736	$	1,724	$	36	$	34	$	—	$	2
Not accounted for as hedges (3)	459		382		1		2		—		1
Total	$	1,195	$	2,106	$	37	$	36	$	—	$	3

(1)Included within Other current assets ($19 million at March 31, 2024 and $17 million at December 31, 2023) or Other non-current assets ($18 million at March 31, 2024 and $19 million at December 31, 2023).

(2)Included within Other current liabilities ($3 million at December 31, 2023).

(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 recognized in the Condensed Consolidated Financial Statements are as follows (in millions):

	Three Months Ended March 31,
	2024		2023
Gain recognized in Accumulated other comprehensive loss	$	97	$	—

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

	Three Months Ended March 31,
	2024		2023
Losses recognized in Total revenue	$	(4)	$	(5)

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Fair Value Measurements and Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2024

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 March 31, 2024 and December 31, 2023 (in millions):

			Fair Value Measurements Using
	Balance at March 31, 2024		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)	$	8,236	$	8,236	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	58	$	—	$	58	$	—
Liabilities
Derivatives (2)
Gross foreign exchange contracts	$	22	$	—	$	22	$	—

			Fair Value Measurements Using
	Balance at December 31, 2023		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)	$	3,204	$	3,204	$	—	$	—
Other investments
Government bonds	$	1	$	—	$	1	$	—
Derivatives (2)
Gross foreign exchange contracts	$	49	$	—	$	49	$	—
Liabilities					0
Derivatives (2)
Gross foreign exchange contracts	$	16	$	—	$	16	$	—

(1)Included within Fiduciary assets or Short-term investments in the Condensed 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):

	March 31, 2024				December 31, 2023
	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	600	$	598	$	600	$	595
Long-term debt	$	15,916	$	15,151	$	9,995	$	9,223

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Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Total revenue	$ 4,070	$ 3,871
United States
Disaggregation of Revenue [Line Items]
Total revenue	1,512	1,495
Americas other than United States
Disaggregation of Revenue [Line Items]
Total revenue	323	301
United Kingdom
Disaggregation of Revenue [Line Items]
Total revenue	583	554
Ireland
Disaggregation of Revenue [Line Items]
Total revenue	33	30
Europe, Middle East, & Africa other than United Kingdom and Ireland
Disaggregation of Revenue [Line Items]
Total revenue	1,209	1,102
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	410	389
Eliminations
Disaggregation of Revenue [Line Items]
Total revenue	(8)	(5)
Commercial Risk Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	1,808	1,778
Reinsurance Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	1,167	1,077
Health Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	733	671
Wealth Solutions | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	$ 370	$ 350

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Revenue from Contracts with Customers - Contract Assets Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Capitalized Cost To Fulfill Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	$ 370	$ 355
Additions	380	362
Amortization	(478)	(462)
Impairment	0	0
Foreign currency translation and other	(3)	2
Balance at end of period	269	257
Capitalized Cost To Obtain Customer Contracts
Change in Capitalized Contract Costs
Balance at beginning of period	195	185
Additions	14	10
Amortization	(13)	(12)
Impairment	0	0
Foreign currency translation and other	(2)	0
Balance at end of period	$ 194	$ 183

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Accelerating Aon United Program - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Sep. 30, 2023	Mar. 31, 2023
Restructuring Cost and Reserve [Line Items]
Charges	$ 119		$ 0
Accelerating Aon United Program
Restructuring Cost and Reserve [Line Items]
Restructuring plan, period		3 years
Expected cost	1,000
Expected cost, cash charges	900
Expected cost, non-cash charges	100
Charges	$ 119

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Accelerating Aon United Program - Changes in the Company’s Liabilities for the Program (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restructuring Reserve [Roll Forward]
Charges	$ 119	$ 0
Accelerating Aon United Program
Restructuring Reserve [Roll Forward]
Liability Balance as of January 1, 2024	100
Charges	119
Cash payments	(37)
Foreign currency translation and other	(1)
Non-cash charges	(48)
Liability balance as of March 31, 2024	133
Liability balance as of March 31, 2024	254
Accelerating Aon United Program | Technology and other
Restructuring Reserve [Roll Forward]
Liability Balance as of January 1, 2024	14
Charges	19
Cash payments	(12)
Foreign currency translation and other	0
Non-cash charges	(7)
Liability balance as of March 31, 2024	14
Liability balance as of March 31, 2024	33
Accelerating Aon United Program | Workforce optimization
Restructuring Reserve [Roll Forward]
Liability Balance as of January 1, 2024	86
Charges	64
Cash payments	(25)
Foreign currency translation and other	(1)
Non-cash charges	(5)
Liability balance as of March 31, 2024	119
Liability balance as of March 31, 2024	167
Accelerating Aon United Program | Asset impairments
Restructuring Reserve [Roll Forward]
Liability Balance as of January 1, 2024	0
Charges	36
Cash payments	0
Foreign currency translation and other	0
Non-cash charges	(36)
Liability balance as of March 31, 2024	0
Liability balance as of March 31, 2024	$ 54

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Cash and Cash Equivalents and Short-Term Investments (Details) £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2024 GBP (£)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 GBP (£)
Cash, Cash Equivalents, and Short-Term Investments [Abstract]
Cash and cash equivalents and short-term investments	$ 6,400		$ 1,100
Increase in cash and cash equivalents and short term investments	5,300
Restricted cash and investments	112		120
Operating funds required to be held in U.K.	$ 70	£ 55	$ 80	£ 63

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Other Financial Data - Schedule of Other Income (Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Financial Data [Abstract]
Foreign currency remeasurement	$ 4	$ (19)
Equity earnings	2	3
Pension and other postretirement	(10)	(17)
Financial instruments and other	79	8
Total	75	$ (25)
Deferred consideration on divestiture	$ 82

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Other Financial Data - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Movement ofAccounts Receivable, Allowance for Credit Loss, Current [Roll Forward]
Balance at beginning of period	$ 79	$ 76
Provision	5	7
Accounts written off, net of recoveries	(2)	0
Foreign currency translation and other	(1)	0
Balance at end of period	$ 81	$ 83

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Other Financial Data - Schedule of Other Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other Financial Data [Abstract]
Assets held for sale	$ 446	$ 354
Cost to fulfill contracts with customers	269	370
Prepaid expenses	128	100
Taxes receivable	19	35
Other	158	137
Total	$ 1,020	$ 996

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Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other Financial Data [Abstract]
Cost to obtain contracts with customers	$ 194	$ 195
Taxes receivable	98	100
Investments	80	45
Leases	21	26
Other	132	140
Total	$ 525	$ 506

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Other Financial Data - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Other Financial Data [Abstract]
Taxes payable	$ 397		$ 291
Deferred revenue	360		270
Leases	179		182
Liabilities held for sale	129		69
Other	1,081		1,066
Total	2,146		$ 1,878
Revenue recognized from deferred revenue	$ 179	$ 167

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Other Financial Data - Schedule of Other Non-current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other Financial Data [Abstract]
Taxes payable	$ 866	$ 827
Compensation and benefits	55	59
Deferred revenue	31	33
Leases	5	10
Other	146	145
Total	1,103	1,074
Noncurrent portion of transition tax	$ 72	$ 72

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Acquisitions and Dispositions of Businesses - Completed Acquisitions (Details) - acquisition	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Nov. 30, 2023	Aug. 30, 2023	Jun. 22, 2023
Business Acquisition [Line Items]
Number of business acquired under business combination	0	0
Gi&Bi S.r.l
Business Acquisition [Line Items]
Percentage of capital acquired			100.00%
N. Goddard Seguros
Business Acquisition [Line Items]
Percentage of capital acquired				100.00%
2023 Acquisitions
Business Acquisition [Line Items]
Percentage of capital acquired					100.00%

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Acquisitions and Dispositions of Businesses - Completed Dispositions (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) disposition	Mar. 31, 2023 USD ($) disposition	Dec. 31, 2023 USD ($)
Business Combination and Asset Acquisition [Abstract]
Number of dispositions | disposition	1	0
Gain from sales of businesses	$ 0	$ 0
Assets held for sale	446,000,000		$ 354,000,000
Liabilities held for sale	129,000,000		$ 69,000,000
Intangible assets held for sale	$ 156,000,000

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Acquisitions and Dispositions of Businesses - Other Significant Activity (Details) - May 1, 2017 Divested Business - Disposal Group, Disposed of by Sale, Not Discontinued Operations - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	May 01, 2017
Dispositions
Purchase price		$ 4,300
Deferred consideration		$ 500
Proceeds from divestiture of businesses	$ 82

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Goodwill and Other Intangible Assets - Schedule of Changes in the Net Carrying Amount of Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 8,414
Foreign currency translation and other	(112)
Ending balance	$ 8,302

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Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets by Asset Class (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,224	$ 2,244
Accumulated Amortization and Impairment	2,007	2,010
Total	217	234
Customer-related and contract-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,857	1,873
Accumulated Amortization and Impairment	1,683	1,686
Total	174	187
Technology and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	367	371
Accumulated Amortization and Impairment	324	324
Total	$ 43	$ 47

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Goodwill and Other Intangible Assets - Schedule of Estimated Future Amortization Expense on Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2024	$ 52
2025	55
2026	34
2027	22
2028	17
2029	12
Thereafter	25
Total	$ 217	$ 234

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Debt - Narrative (Details)	Mar. 31, 2024 USD ($) credit_facility	Mar. 31, 2024 EUR (€) credit_facility	Mar. 01, 2024 USD ($)	Feb. 16, 2024 USD ($)	Dec. 31, 2023 USD ($)	Nov. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Feb. 28, 2023 USD ($)
Debt Instrument [Line Items]
Number of credit facilities | credit_facility	2	2
Borrowings under credit facilities	$ 0				$ 0
Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 6,000,000,000
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, available credit	2,000,000,000
Line of Credit | Credit Facility Expiring September 2027
Debt Instrument [Line Items]
Maximum borrowing capacity	1,000,000,000
Line of Credit | Credit Facility Expiring October 2028
Debt Instrument [Line Items]
Maximum borrowing capacity	1,000,000,000
5.125% Senior Notes Due March 2027 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 600,000,000
Debt interest rate percentage			5.125%
5.150% Senior Notes Due March 2029 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 1,000,000,000
Debt interest rate percentage			5.15%
5.300% Senior Notes Due March 2031 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 650,000,000
Debt interest rate percentage			5.30%
5.450% Senior Notes Due March 2034 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 1,750,000,000
Debt interest rate percentage			5.45%
5.750% Senior Notes Due March 2054 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 2,000,000,000
Debt interest rate percentage			5.75%
4.00% Senior Notes Due November 2023 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount						$ 350,000,000
Debt interest rate percentage						4.00%
3.50% Senior Notes Due June 2024 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount							$ 600,000,000
Debt interest rate percentage							3.50%
5.350% Senior Notes Due February 2033 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount								$ 750,000,000
Debt interest rate percentage								5.35%
Delayed Draw Term Loan | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 2,000,000,000
U.S. Program | Commercial paper outstanding
Debt Instrument [Line Items]
Maximum borrowing capacity	1,300,000,000
European Program | Commercial paper outstanding
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 677,000,000	€ 625,000,000

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Debt - Schedule of Commercial Paper Outstanding (Details) - Commercial paper outstanding - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Commercial paper outstanding	$ 0		$ 597
Weighted average commercial paper outstanding	$ 381	$ 393
Weighted average interest rate of commercial paper outstanding	5.65%	3.38%

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Income Taxes (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Effective income tax rate	23.20%	19.60%

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Shareholders' Equity (Deficit) - Narrative (Details) - USD ($) shares in Millions	1 Months Ended				3 Months Ended		138 Months Ended
	Feb. 28, 2022	Nov. 30, 2020	Jun. 30, 2017	Nov. 30, 2014	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023	Apr. 30, 2012
Equity [Abstract]
Share repurchase authorization amount					$ 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
Share repurchase, remaining authorized repurchase amount					$ 3,100,000,000
Shares purchased (in shares)					0.8	1.8	169.9
Total cost of shares purchased					$ 250,000,000	$ 550,000,000	$ 24,400,000,000
Antidilutive securities excluded from computation of earnings per share (in shares)					0.1	0.0

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Shareholders' Equity (Deficit) - Schedule of Stock Repurchases (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		138 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Equity [Abstract]
Shares repurchased (in shares)	0.8	1.8	169.9
Average price per share (in dollars per share)	$ 310.56	$ 305.31
Repurchase costs recorded to accumulated deficit	$ 250	$ 550	$ 24,400

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Shareholders' Equity (Deficit) - Weighted Average Ordinary Shares Outstanding (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Equity [Abstract]
Basic weighted average ordinary shares outstanding (in shares)	199.1	206.1
Dilutive effect of potentially issuable shares (in shares)	1.0	1.0
Diluted weighted average ordinary shares outstanding (in shares)	200.1	207.1

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Shareholders' Equity (Deficit) - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ (742)	$ (429)
Other comprehensive income (loss) before reclassifications, net	(60)	53
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	39	37
Tax expense	(10)	(11)
Amounts reclassified from accumulated other comprehensive income, net	29	26
Total other comprehensive income (loss)	(31)	79
Ending balance	(28)	58
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(4,373)	(4,623)
Amounts reclassified from accumulated other comprehensive income
Ending balance	(4,404)	(4,544)
Change in Fair Value of Financial Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2	(11)
Other comprehensive income (loss) before reclassifications, net	72	0
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	4	5
Tax expense	(1)	(2)
Amounts reclassified from accumulated other comprehensive income, net	3	3
Total other comprehensive income (loss)	75	3
Ending balance	77	(8)
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,584)	(1,861)
Other comprehensive income (loss) before reclassifications, net	(132)	54
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	0	0
Tax expense	0	0
Amounts reclassified from accumulated other comprehensive income, net	0	0
Total other comprehensive income (loss)	(132)	54
Ending balance	(1,716)	(1,807)
Postretirement Benefit Obligation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(2,791)	(2,751)
Other comprehensive income (loss) before reclassifications, net	0	(1)
Amounts reclassified from accumulated other comprehensive income
Amounts reclassified from accumulated other comprehensive income	35	32
Tax expense	(9)	(9)
Amounts reclassified from accumulated other comprehensive income, net	26	23
Total other comprehensive income (loss)	26	22
Ending balance	$ (2,765)	$ (2,729)

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Employee Benefits - Components of Net Periodic (Benefit) Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
U.K.
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0
Interest cost	35	36
Expected return on plan assets, net of administration expenses	(47)	(46)
Amortization of prior-service cost	1	0
Amortization of net actuarial loss	20	18
Net periodic (benefit) cost	9	8
Loss on pension settlement	0	0
Total net periodic (benefit) cost	9	8
Other
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	9	10
Expected return on plan assets, net of administration expenses	(13)	(12)
Amortization of prior-service cost	0	0
Amortization of net actuarial loss	3	3
Net periodic (benefit) cost	(1)	1
Loss on pension settlement	0	0
Total net periodic (benefit) cost	(1)	1
U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	23	26
Expected return on plan assets, net of administration expenses	(33)	(30)
Amortization of prior-service cost	0	0
Amortization of net actuarial loss	7	9
Net periodic (benefit) cost	(3)	5
Loss on pension settlement	0	0
Total net periodic (benefit) cost	$ (3)	$ 5

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Employee Benefits - Narrative (Details) $ in Millions	Mar. 31, 2024 USD ($)
U.K.
Defined Benefit Plan Disclosure [Line Items]
Expected future employer cash contribution	$ 2
Other
Defined Benefit Plan Disclosure [Line Items]
Expected future employer cash contribution	13
U.S.
Defined Benefit Plan Disclosure [Line Items]
Expected future employer cash contribution	$ 53

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Employee Benefits - Schedule of Employer Contributions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Company’s benefit pension plans	$ 17	$ 23
U.K.
Defined Benefit Plan Disclosure [Line Items]
Company’s benefit pension plans	1	1
Other
Defined Benefit Plan Disclosure [Line Items]
Company’s benefit pension plans	2	6
U.S.
Defined Benefit Plan Disclosure [Line Items]
Company’s benefit pension plans	$ 14	$ 16

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Derivatives and Hedging - Foreign Exchange Risk Management Narrative (Details)	3 Months Ended
	Mar. 31, 2024
Not designated as hedging instrument | Foreign exchange contracts
Derivative [Line Items]
Term of derivative contract	90 days
Not designated as hedging instrument | Foreign exchange contracts | Maximum
Derivative [Line Items]
Term of derivative contract	1 year
Cash Flow Hedging
Derivative [Line Items]
Foreign currency exposures, maximum average hedging period (less than) (in years)	2 years

XML

Derivatives and Hedging - Notional and Fair Values of Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Other Current Assets
Derivative [Line Items]
Net amount of derivative assets	$ 19	$ 17
Other Noncurrent Assets
Derivative [Line Items]
Net amount of derivative assets	18	19
Other Current Liabilities
Derivative [Line Items]
Net amount of derivative liabilities		3
Foreign exchange contracts
Derivative [Line Items]
Notional Amount	1,195	2,106
Net amount of derivative assets	37	36
Net amount of derivative liabilities	0	3
Accounted for as hedges | Foreign exchange contracts
Derivative [Line Items]
Notional Amount	736	1,724
Net amount of derivative assets	36	34
Net amount of derivative liabilities	0	2
Not accounted for as hedges | Foreign exchange contracts
Derivative [Line Items]
Notional Amount	459	382
Net amount of derivative assets	1	2
Net amount of derivative liabilities	$ 0	$ 1
Term of derivative contract	90 days

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Derivatives and Hedging - Schedule of Derivative Gains (Losses) Recognized in the Consolidated Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Gain recognized in Accumulated other comprehensive loss	$ 97	$ 0
Losses recognized in Total revenue
Derivative [Line Items]
Losses recognized in Total revenue	$ (4)	$ (5)

XML

Derivatives and Hedging - Interest Rate Management Risk Narrative (Details) - Foreign exchange contracts - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Pretax gains that will be reclassified into earnings in the next twelve months	$ 2
Not designated as hedging instrument
Derivative [Line Items]
Gain (loss) on derivative	$ (3)	$ 9

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	Mar. 31, 2024	Dec. 31, 2023
Money market funds
Assets
Money market funds	$ 8,236	$ 3,204
Government bonds
Assets
Other investments	1	1
Gross foreign exchange contracts
Assets
Derivatives	58	49
Liabilities
Derivatives	22	16
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets
Money market funds	8,236	3,204
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
Derivatives	0	0
Liabilities
Derivatives	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
Derivatives	58	49
Liabilities
Derivatives	22	16
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
Derivatives	0	0
Liabilities
Derivatives	$ 0	$ 0

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Fair Value Measurements and Financial Instruments - Schedule of Financial Instruments where the Carrying Amounts and Fair Values Differ (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 15,916	$ 9,995
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long-term debt	600	600
Long-term debt	15,916	9,995
Fair Value | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long-term debt, fair value	598	595
Long term debt, fair value	$ 15,151	$ 9,223

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Claims, Lawsuits, and Other Contingencies - Legal Narrative (Details) - Fatal Plain Crash In November 2016 £ in Millions, $ in Millions		1 Months Ended					3 Months Ended
	Mar. 31, 2024 USD ($)	Feb. 29, 2024 plaintiff	Apr. 30, 2021 GBP (£) plaintiff	Aug. 31, 2020 USD ($) plaintiff	Nov. 30, 2019 USD ($) defendant	Nov. 30, 2018 USD ($)	Dec. 31, 2023 USD ($)
Pending Litigation
Legal, Guarantees and Indemnifications
Damages sought	$ 37		£ 29	$ 844		$ 16
Number of defendants | defendant					3
Damages sought option 1					$ 300
Damages sought option 2					50
Damages sought option 3					$ 25
Number of plaintiffs | plaintiff			16	43
Litigation settlement expense							$ 197
Settled Litigation
Legal, Guarantees and Indemnifications
Number of plaintiffs | plaintiff		16

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Claims, Lawsuits, and Other Contingencies - Letters of Credit Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Letters of credit outstanding	$ 139	$ 86

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Claims, Lawsuits, and Other Contingencies - Premium Payments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Maximum potential funding under commitments	$ 110	$ 194

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Segment Information (Details)	3 Months Ended
	Mar. 31, 2024 segment performance_metric revenue_line
Segment Reporting [Abstract]
Number of reportable segment | segment	1
Number of solution lines | revenue_line	4
Number of performance metrics | performance_metric	4

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Subsequent Events (Details) - Subsequent Event shares in Millions, $ in Billions	Apr. 25, 2024 USD ($) employee shares	Apr. 02, 2024
NFP
Subsequent Event [Line Items]
Number of colleagues (more than) | employee	7,700
NFP | Senior Notes | 6.875% Senior Notes Due 2028
Subsequent Event [Line Items]
Debt interest rate percentage		6.875%
NFP | Senior Notes | 4.875% Senior Notes Due 2028
Subsequent Event [Line Items]
Debt interest rate percentage		4.875%
NFP | Senior Notes | 7.500% Senior Secured Notes Due 2030
Subsequent Event [Line Items]
Debt interest rate percentage		7.50%
NFP | Senior Notes | 8.500% Senior Secured Notes Due 2031
Subsequent Event [Line Items]
Debt interest rate percentage		8.50%
NFP
Subsequent Event [Line Items]
Total consideration	$ 9.1
Payments to acquire businesses, gross	$ 3.2
Number of shares issued for acquisition (up to) | shares	19
Equity interest issued or issuable, value	$ 5.9