Willis Towers Watson Public Limited (WTW) 10-Q 25 Apr 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 22, 2024
Cover [Abstract]
Amendment Flag	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Registrant Name	WILLIS TOWERS WATSON PLC
Entity Central Index Key	0001140536
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		102,235,963
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Trading Symbol	WTW
Title of 12(b) Security	Ordinary Shares, nominal value $0.000304635 per share
Security Exchange Name	NASDAQ
Entity File Number	001-16503
Entity Incorporation, State or Country Code	L2
Entity Tax Identification Number	98-0352587
Entity Address, Address Line One	c/o Willis Group Limited
Entity Address, Address Line Two	51 Lime Street
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	EC3M 7DQ
City Area Code	011
Local Phone Number	44-20-3124-6000
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 2,341	$ 2,244
Costs of providing services
Salaries and benefits	1,342	1,313
Other operating expenses	457	453
Depreciation	59	60
Amortization	60	71
Restructuring costs	18	3
Transaction and transformation	125	59
Total costs of providing services	2,061	1,959
Income from operations	280	285
Interest expense	(64)	(54)
Other income, net	26	25
INCOME FROM OPERATIONS BEFORE INCOME TAXES	242	256
Provision for income taxes	(48)	(50)
NET INCOME	194	206
Income attributable to non-controlling interests	(4)	(3)
NET INCOME ATTRIBUTABLE TO WTW	$ 190	$ 203
Basic earnings per share:
Basic earnings per share	$ 1.84	$ 1.89
Diluted earnings per share:
Diluted earnings per share	$ 1.83	$ 1.88
Comprehensive income before non-controlling interests	$ 145	$ 259
Comprehensive income attributable to non-controlling interests	(4)	(3)
Comprehensive income attributable to WTW	$ 141	$ 256

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
ASSETS
Cash and cash equivalents	$ 1,893	$ 1,424
Fiduciary assets	9,940	9,073
Accounts receivable, net	2,430	2,572
Prepaid and other current assets	379	364
Total current assets	14,642	13,433
Fixed assets, net	703	720
Goodwill	10,186	10,195
Other intangible assets, net	1,960	2,016
Right-of-use assets	542	565
Pension benefits assets	598	588
Other non-current assets	1,606	1,573
Total non-current assets	15,595	15,657
TOTAL ASSETS	30,237	29,090
LIABILITIES AND EQUITY
Fiduciary liabilities	9,940	9,073
Deferred revenue and accrued expenses	1,638	2,104
Current debt	650	650
Current lease liabilities	123	125
Other current liabilities	767	678
Total current liabilities	13,118	12,630
Long-term debt	5,307	4,567
Liability for pension benefits	526	563
Deferred tax liabilities	550	542
Provision for liabilities	377	365
Long-term lease liabilities	570	592
Other non-current liabilities	221	238
Total non-current liabilities	7,551	6,867
TOTAL LIABILITIES	20,669	19,497
COMMITMENTS AND CONTINGENCIES
EQUITY
Additional paid-in capital	10,930	10,910
Retained earnings	1,464	1,466
Accumulated other comprehensive loss, net of tax	(2,905)	(2,856)
Total WTW shareholders' equity	9,489	9,520
Non-controlling interests	79	73
Total equity	9,568	9,593
TOTAL LIABILITIES AND EQUITY	$ 30,237	$ 29,090

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Preference shares, nominal value (USD per share)	$ 0.000115	$ 0.000115
Preference shares, shares authorized	1,000,000,000	1,000,000,000
Preference shares, shares issued	0	0
Ordinary shares, $0.000304635 nominal value [Member]
Ordinary shares, nominal value	$ 0.000304635	$ 0.000304635
Ordinary shares, shares authorized	1,510,003,775	1,510,003,775
Ordinary shares, shares issued	102,213,184	102,538,072
Ordinary shares, shares outstanding	102,213,184	102,538,072

Condensed Consolidated Statem_2

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		$ 194	$ 206
Adjustments to reconcile net income to total net cash from operating activities:
Depreciation		59	60
Amortization		60	71
Non-cash restructuring charges		11	2
Non-cash lease expense		27	27
Net periodic benefit of defined benefit pension plans		(4)	(8)
Provision for doubtful receivables from clients		8	7
Benefit from deferred income taxes		(9)	(15)
Share-based compensation		24	26
Non-cash foreign exchange (gain)/loss		(1)	11
Other, net		8	10
Changes in operating assets and liabilities, net of effects from purchase of subsidiaries:
Accounts receivable		113	129
Other assets		(53)	11
Other liabilities		(426)	(411)
Provisions		13	8
Net cash from operating activities		24	134
CASH FLOWS USED IN INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		(33)	(42)
Capitalized software costs		(27)	(19)
Acquisitions of operations, net of cash acquired		(15)	(4)
Sale of investments		1	4
Net cash used in investing activities		(74)	(61)
CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES
Senior notes issued		746	0
Debt issuance costs		(7)	0
Repayments of debt		(1)	(1)
Repurchase of shares		(101)	(104)
Net proceeds/(payments) from fiduciary funds held for clients		1,011	(250)
Payments of deferred and contingent consideration related to acquisitions		0	(6)
Cash paid for employee taxes on withholding shares		(5)	(5)
Dividends paid		(86)	(87)
Acquisitions of and dividends paid to non-controlling interests		(1)	0
Net cash from/(used in) financing activities		1,556	(453)
INCREASE/(DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	[1]	1,506	(380)
Effect of exchange rate changes on cash, cash equivalents and restricted cash		(47)	21
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD	[1]	3,792	4,721
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD	[1]	$ 5,251	$ 4,362
[1] The amounts of cash, cash equivalents and restricted cash, their respective classification on the condensed consolidated balance sheets as well as their respective portions of the increase or decrease in cash, cash equivalents and restricted cash for each of the periods presented have been included in Note 19 — Supplemental Disclosures of Cash Flow Information.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions		Total	Shares outstanding [Member]	Ordinary shares and APIC [Member]	Retained earnings [Member]	Treasury Stock Common [Member]	AOCL [Member]	[1]	Total WTW shareholders' equity [Member]	Non-controlling interests [Member]
Equity, beginning balance at Dec. 31, 2022		$ 10,093		$ 10,876	$ 1,764	$ (3)	$ (2,621)		$ 10,016	$ 77
Equity, beginning balance (in shares) at Dec. 31, 2022			106,756
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased (in shares)			(432)
Shares repurchased		(104)		(3)	(104)	3			(104)
Net income		206			203				203	3
Dividends declared		(89)			(89)				(89)
Other comprehensive (loss)/income		53					53		53
Issuance of shares under employee stock compensation plans (in shares)			59
Share-based compensation and net settlements		18		18					18
Foreign currency translation		(1)		(1)					(1)
Equity, ending balance at Mar. 31, 2023		10,176		10,890	1,774	0	(2,568)		10,096	80
Equity, ending balance (in shares) at Mar. 31, 2023			106,383
Equity, beginning balance at Dec. 31, 2023		9,593		10,910	1,466	0	(2,856)		9,520	73
Equity, beginning balance (in shares) at Dec. 31, 2023			102,538
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased (in shares)			(374)
Shares repurchased		(101)			(101)				(101)
Net income		194			190				190	4
Dividends declared		(91)			(91)				(91)
Dividends attributable to non-controlling interests		(1)								(1)
Other comprehensive (loss)/income		(49)					(49)		(49)
Issuance of shares under employee stock compensation plans		0		0					0
Issuance of shares under employee stock compensation plans (in shares)			49
Share-based compensation and net settlements		16		16					16
Additional non-controlling interests	[2]	3								3
Foreign currency translation		4		4					4
Equity, ending balance at Mar. 31, 2024		$ 9,568		$ 10,930	$ 1,464	$ 0	$ (2,905)		$ 9,489	$ 79
Equity, ending balance (in shares) at Mar. 31, 2024			102,213
[1] Accumulated other comprehensive loss, net of tax (‘AOCL’). Attributable to the divestiture of businesses that are less than wholly-owned or the acquisition of shares previously owned by minority interest holders. In an acquisition, additional paid-in capital is adjusted as well to the extent that the consideration transferred differs from the carrying value of non-controlling interests prior to the acquisition.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Stockholders' Equity [Abstract]
Dividends declared per share	$ 0.88	$ 0.84

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 190	$ 203

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b51 Arr Modified Flag	false
Non Rule 10b51 Arr Modified Flag	false

Nature of Operations

Nature of Operations	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Note 1 — Nature of Operations Willis Towers Watson Public Limited Company is a leading global advisory, broking and solutions company that provides data-driven, insight-led solutions in the areas of people, risk and capital. The Company has 48,000 colleagues serving more than 140 countries and markets. We design and deliver solutions that manage risk, optimize benefits, cultivate talent and expand the power of capital to protect and strengthen institutions and individuals. Our risk control services include strategic risk consulting (including providing actuarial analysis), a variety of due diligence services, the provision of practical on-site risk control services (such as health and safety or property loss control consulting), and analytical and advisory services (such as hazard modeling and climate risk quantification). We also assist our clients with managing incidents or crises when they occur. These services include contingency planning, security audits and product tampering plans. We help our clients enhance their business performance by delivering consulting services, technology and solutions that help them anticipate, identify and capitalize on emerging opportunities in human capital management, as well as offer investment advice to help them develop disciplined and efficient strategies to meet their investment goals. As an insurance broker, we act as an intermediary between our clients and insurance carriers by advising on their risk management requirements, helping them to determine the best means of managing risk and negotiating and placing insurance with insurance carriers through our global distribution network. We operate a private Medicare marketplace in the U.S. through which, along with our active employee marketplace, we help our clients move to a more sustainable economic model by capping and controlling the costs associated with healthcare benefits. We also provide direct-to-consumer sales of Medicare coverage. We are not an insurance company, and therefore we do not underwrite insurable risks for our own account. We help sharpen strategies, enhance organizational resilience, motivate workforces and maximize performance to uncover opportunities for sustainable success.

Basis of Presentation and Recen

Basis of Presentation and Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation and Recent Accounting Pronouncements	Note 2 — Basis of Presentation and Recent Accounting Pronouncements Basis of Presentation The accompanying unaudited quarterly condensed consolidated financial statements of WTW and our subsidiaries are presented in accordance with the rules and regulations of the SEC for quarterly reports on Form 10-Q and therefore certain footnote disclosures have been condensed or omitted from these financial statements as they are not required for interim reporting under U.S. GAAP. In the opinion of management, these condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, which are necessary for a fair presentation of the condensed consolidated financial statements and results for the interim periods. All intercompany accounts and transactions have been eliminated in consolidation. The condensed consolidated financial statements should be read together with the Company’s Annual Report on Form 10-K, filed with the SEC on February 22, 2024, and may be accessed via EDGAR on the SEC’s web site at www.sec.gov. The results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results that can be expected for the entire year. The Company experiences seasonal fluctuations of its revenue. Revenue is typically higher during the Company’s first and fourth quarters due primarily to the timing of broking-related activities. The results reflect certain estimates and assumptions made by management, including those estimates used in calculating acquisition consideration and fair value of tangible and intangible assets and acquisition-related liabilities, professional liability claims, estimated bonuses, valuation of billed and unbilled receivables, and anticipated tax liabilities that affect the amounts reported in the condensed consolidated financial statements and related notes. Recent Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , which is intended to improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information within the income tax rate reconciliation and income taxes paid disclosures. It also includes certain other amendments intended to improve the effectiveness of income tax disclosures. Specifically, this ASU requires a tabular income tax rate reconciliation using both percentages and amounts disaggregated into specific categories with certain reconciling items at or above 5% of the statutory tax, further disaggregated by its nature and/or jurisdiction. Additionally, income taxes paid will be required to be presented by federal, state, local and foreign jurisdictions, including amounts paid to individual jurisdictions representing 5% or more of the total income taxes paid. This ASU becomes effective for the Company on January 1, 2025, with early adoption permitted. The guidance is applied prospectively, with the option for retrospective application. The Company does not plan to early-adopt this ASU and is assessing the expected impact on its condensed consolidated financial statements. In March 2024, the SEC adopted final rules on the enhancement and standardization of climate-related disclosures for investors. The rules require disclosure of certain climate-related information in registration statements and annual reports on Form 10-K. For example, the rules require the notes to the financial statements to include disclosure regarding the effects of severe weather events and other natural conditions, subject to certain materiality thresholds. Additionally, the rules also require certain other disclosures outside of the financial statements. Among other things, these requirements include Scope 1 (direct) and Scope 2 (indirect from purchased energy) greenhouse gas (‘GHG’) emissions, if material, which will be subject to assurance requirements that will be phased in, as well as governance, oversight and risk management disclosures, which include any transition plan adopted to manage material transition risk, and material climate targets and goals. The rules become effective in phases, currently beginning with any material current-year effects of severe weather events and other natural conditions and the more qualitative disclosures being required for inclusion in the Company’s 2025 Form 10-K, and some of the other more quantitative disclosures being required for the 2026 Form 10-K. While the disclosures are meant to cover the same periods in the financial statements, the requirements may be adopted on a prospective basis beginning with 2025. The Scope 1 and Scope 2 GHG emissions disclosures, which are required for the 2026 fiscal year, allow for additional time but must be filed by the due date of the second quarterly report on Form 10-Q or by amending the Form 10-K by that same deadline. Third-party limited assurance of the GHG emissions disclosures is required for the Company’s 2029 Form 10-K and reasonable assurance is required for the Company’s 2033 Form 10-K. Following a number of legal challenges to the final rule that have been consolidated for review in the U.S. Court of Appeals for the Eighth Circuit, the SEC has voluntarily stayed the newly-released climate rules pending the completion of judicial review of such consolidated petitions to avoid regulatory uncertainty for companies subject to the rule while the litigation proceeds. The Company is monitoring the outcome of the litigation and will provide the required disclosures if and when required. Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , which is intended to improve reportable segment disclosure requirements through enhanced disclosures about significant segment expenses. Among other amendments, this ASU creates a ‘significant expense principle,’ and adds required disclosures of significant expenses for each reportable segment, as well as certain other disclosures to help investors understand how the chief operating decision maker (‘CODM’) evaluates segment expenses and operating results. In addition, this ASU requires for interim periods all disclosures about a reportable segment’s profit or loss and assets under ASC 280, Segment Reporting that had previously only been provided annually (e.g., interest income and expense, depreciation and amortization expense). The annual requirements of this ASU became effective for the Company on January 1, 2024, at which time it was adopted; the Company will include the new disclosures in our Annual Report on Form 10-K for the year ended December 31, 2024, as required. New interim disclosures are required for fiscal years beginning January 1, 2025 and will be included at that time. Other Legislation Inflation Reduction Act The Inflation Reduction Act (the ‘IRA’) was enacted into law on August 16, 2022 and certain portions of the IRA became effective January 1, 2023. The IRA introduced, among other provisions, a share repurchase excise tax and a new Corporate Alternative Minimum Tax (‘CAMT’) which imposes a 15% tax on the adjusted financial statement income of ‘applicable corporations’. New rules issued in the proposed regulations issued on April 9, 2024 apply to share repurchases after April 12, 2024. The Company does not expect the excise tax or CAMT to have a significant impact on its condensed consolidated financial statements. Pillar Two On October 8, 2021, the Organisation for Economic Co-operation and Development (‘OECD’) announced an international agreement with more than 140 countries to implement a two-pillar solution to address tax challenges arising from the digitalization of the economy. The agreement introduced rules that would result in the reallocation of certain taxing rights over multinational companies from their home countries to the markets where they have business activities and earn profits, regardless of physical presence (‘Pillar One’) and introduced a global corporate minimum tax of 15% for certain large multinational companies starting in 2024 (‘Pillar Two’). On December 20, 2021, the OECD/G20 Inclusive Framework on Base Erosion and Profit Shifting released the Model Global Anti-Base Erosion (‘GloBE’) rules (the ‘OECD Model Rules’) under Pillar Two. On December 12, 2022, E.U. member states reached an agreement to implement Pillar Two and this requires E.U. member states to enact domestic legislation to put Pillar Two into effect. In 2023, many E.U. countries enacted the necessary legislation (based on the OECD Model Rules) to implement Pillar Two in 2024. Ireland, in particular, enacted Pillar Two by signing Finance (No. 2) Bill 2023 into law in December 2023. Other countries and territories have indicated they will introduce Pillar Two beginning in 2025. While we do not anticipate that this legislation will have a material impact on our tax provision or effective tax rate, we continue to monitor evolving tax legislation in the jurisdictions in which we operate.

Acquisitions and Divestitures

Acquisitions and Divestitures	3 Months Ended
	Mar. 31, 2024
Dispositions [Abstract]
Acquisitions and Divestitures	Note 3 — Acquisitions and Divestitures Acquisitions The Company completed acquisitions during the three months ended March 31, 2024 for combined cash payments of $ 24 million and contingent consideration fair valued at $ 3 million. Divestitures Willis Re Divestiture On August 13, 2021, the Company entered into a definitive security and asset purchase agreement (the ‘Willis Re SAPA’) to sell its treaty-reinsurance business (‘Willis Re’) to Arthur J. Gallagher & Co. (‘Gallagher’), a leading global provider of insurance, risk management and consulting services, for total upfront cash consideration of $ 3.25 billion plus an earnout payable in 2025 of up to $ 750 million in cash, subject to certain adjustments. The deal was subject to required regulatory approvals and clearances, as well as other customary closing conditions, and was completed on December 1, 2021. Certain amounts included in the condensed consolidated balance sheets did not transfer to Gallagher under the terms of the Willis Re SAPA, and instead were to be settled by the Company, noting that certain fiduciary positions continued to be held under the terms of various co-broking agreements between subsidiaries of the Company and Gallagher. On May 31, 2023, the Company and Gallagher entered into a side letter to the Willis Re SAPA which became effective on June 1, 2023 and which (A) ended the co-broking agreements prospectively and (B) transferred related fiduciary and certain non-fiduciary assets and liabilities to Gallagher at that time based on then-current estimates. These non-fiduciary amounts were finalized in the third quarter of 2023. The value of the initial transfer during the second quarter of 2023 amounted to $ 74 million of other current liabilities less $ 26 million of accounts receivables due to the Company, totaling $ 48 million of net cash transferred to Gallagher. Additionally, total fiduciary assets and liabilities of $ 4.5 billion, including $ 868 million of fiduciary cash, were transferred to Gallagher. The total cash outflow of $ 916 million was included in cash used in investing activities in the condensed consolidated statements of cash flows for the six months ended June 30, 2023. During the third quarter of 2023, WTW and Gallagher agreed to a final settlement of all balances which resulted in a $ 5 million increase to the gain on disposal recognized at that time, and is included within Other income, net on our condensed consolidated statements of comprehensive income. The settlement of remaining amounts owed to Gallagher totaling $ 11 million was transferred in October 2023. A number of services are continuing under a cost reimbursement Transition Services Agreement (‘TSA’) in which WTW is providing Gallagher support including real estate leases, information technology, payroll, human resources and accounting. During the third quarter of 2023, the term for these services was extended from November 30, 2023 to May 31, 2024 and may be further extended by Gallagher, in accordance with the terms of the TSA. Fees earned under the TSA were $ 6 million and $ 9 million during the three months ended March 31, 2024 and 2023, respectively, and have been recognized as a reduction to the costs incurred to service the TSA and are included within Other operating expenses on the condensed consolidated statements of comprehensive income. Costs incurred to service the TSA are expected to be reduced as part of the Company’s Transformation program (see Note 6 — Restructuring Costs for a description of the program) as quickly as possible when the services are no longer required by Gallagher.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue	Note 4 — Revenue Disaggregation of Revenue The Company reports revenue by segment in Note 5 — Segment Information. The following table presents revenue by service offering and segment, as well as a reconciliation to total revenue for the three months ended March 31, 2024 and 2023. Along with reimbursable expenses and other, total revenue by service offering represents our revenue from customer contracts. Three Months Ended March 31, HWC R&B Corporate (i) Total 2024 2023 2024 2023 2024 2023 2024 2023 Broking $ 335 $ 289 $ 742 $ 691 $ — $ 5 $ 1,077 $ 985 Consulting 662 661 104 98 1 4 767 763 Outsourced administration 266 262 30 29 — — 296 291 Other 64 69 71 67 — — 135 136 Total revenue by service offering 1,327 1,281 947 885 1 9 2,275 2,175 Reimbursable expenses and other (i) 17 15 3 3 — 10 20 28 Total revenue from customer contracts $ 1,344 $ 1,296 $ 950 $ 888 $ 1 $ 19 $ 2,295 $ 2,203 Interest and other income 9 6 31 19 6 16 46 41 Total revenue $ 1,353 $ 1,302 $ 981 $ 907 $ 7 $ 35 $ 2,341 $ 2,244 (i) Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions. Interest and other income is included in segment revenue and total revenue, however it has been presented separately in the above tables because it does not arise directly from contracts with customers. The significant components of interest and other income are as follows for the periods presented above: Three Months Ended March 31, HWC R&B Corporate Total 2024 2023 2024 2023 2024 2023 2024 2023 Book-of-business settlements $ — $ — $ 2 $ 7 $ — $ — $ 2 $ 7 Interest income 9 5 28 12 6 15 43 32 Other income — 1 1 — — 1 1 2 Total interest and other income $ 9 $ 6 $ 31 $ 19 $ 6 $ 16 $ 46 $ 41 As a result of the cessation of the co-broking agreement, (see Note 3 — Acquisitions and Divestitures) interest income associated with fiduciary funds is now allocated more directly to the Risk and Broking segment beginning in the third quarter of 2023. These amounts were previously allocated to the Corporate segment following the disposal of Willis Re. The following table presents revenue from service offerings by the geography where our work was performed for the three months ended March 31, 2024 and 2023. The reconciliation to total revenue on our condensed consolidated statements of comprehensive income and to segment revenue is shown in the table above. Three Months Ended March 31, HWC R&B Corporate Total 2024 2023 2024 2023 2024 2023 2024 2023 North America $ 840 $ 823 $ 306 $ 291 $ — $ 1 $ 1,146 $ 1,115 Europe 372 346 511 471 1 7 884 824 International 115 112 130 123 — 1 245 236 Total revenue by geography $ 1,327 $ 1,281 $ 947 $ 885 $ 1 $ 9 $ 2,275 $ 2,175 Contract Balances The Company reports accounts receivable, net on the condensed consolidated balance sheets, which includes billed and unbilled receivables and current contract assets. In addition to accounts receivable, net, the Company had the following non-current contract assets and deferred revenue balances at March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Billed receivables, net of allowance for doubtful accounts of $ 39 million and $ 34 million $ 1,511 $ 1,581 Unbilled receivables 537 491 Current contract assets 382 500 Accounts receivable, net $ 2,430 $ 2,572 Non-current accounts receivable, net $ 19 $ 19 Non-current contract assets $ 925 $ 909 Deferred revenue $ 757 $ 677 During the three months ended March 31, 2024 , revenue of approximately $ 295 million was recognized that was reflected as deferred revenue at December 31, 2023. During the three months ended March 31, 2024 , the Company recognized revenue of approximately $ 9 million related to performance obligations satisfied in a prior period. Performance Obligations The Company has contracts for which performance obligations have not been satisfied as of March 31, 2024 or have been partially satisfied as of this date. The following table shows the expected timing for the satisfaction of the remaining performance obligations. This table does not include contract renewals or variable consideration, which was excluded from the transaction prices in accordance with the guidance on constraining estimates of variable consideration. In addition, in accordance with ASC 606, Revenue From Contracts With Customers (‘ASC 606’), the Company has elected not to disclose the remaining performance obligations when one or both of the following circumstances apply: • Performance obligations which are part of a contract that has an original expected duration of less than one year , and • Performance obligations satisfied in accordance with ASC 606-10-55-18 (‘right to invoice’). Remainder of 2024 2025 2026 onward Total Revenue expected to be recognized on contracts as of March 31, 2024 $ 403 $ 396 $ 511 $ 1,310 Since most of the Company’s contracts are cancellable with less than one year’s notice and have no substantive penalty for cancellation, the majority of the Company’s remaining performance obligations as of March 31, 2024 have been excluded from the table above.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Information	Note 5 — Segment Information WTW has two reportable operating segments or business areas: • Health, Wealth & Career (‘HWC’); and • Risk & Broking (‘R&B’). WTW’s chief operating decision maker is its chief executive officer. We determined that the operational data used by the chief operating decision maker is at the segment level. Management bases strategic goals and decisions on these segments and the data presented below is used to assess the adequacy of strategic decisions and the methods of achieving these strategies and related financial results. Management evaluates the performance of its segments and allocates resources to them based on net operating income on a pre-tax basis. The Company experiences seasonal fluctuations of its revenue. Revenue is typically higher during the Company’s first and fourth quarters due primarily to the timing of broking-related activities. The following table presents segment revenue and segment operating income for our reportable segments for the three months ended March 31, 2024 and 2023. Three Months Ended March 31, HWC R&B Total 2024 2023 2024 2023 2024 2023 Segment revenue $ 1,336 $ 1,287 $ 978 $ 904 $ 2,314 $ 2,191 Segment operating income $ 336 $ 309 $ 203 $ 180 $ 539 $ 489 The following table presents reconciliations of the information reported by segment to the Company’s condensed consolidated statements of comprehensive income amounts reported for the three months ended March 31, 2024 and 2023. Three Months Ended 2024 2023 Revenue: Total segment revenue $ 2,314 $ 2,191 Reimbursable expenses and other 27 53 Revenue $ 2,341 $ 2,244 Total segment operating income $ 539 $ 489 Amortization ( 60 ) ( 71 ) Restructuring costs (i) ( 18 ) ( 3 ) Transaction and transformation (ii) ( 125 ) ( 59 ) Unallocated, net (iii) ( 56 ) ( 71 ) Income from operations 280 285 Interest expense ( 64 ) ( 54 ) Other income, net 26 25 Income from operations before income taxes $ 242 $ 256 (i) See Note 6 — Restructuring Costs for the composition of costs for 2024 and 2023. (ii) In 2024 and 2023, in addition to legal fees and other transaction costs, includes primarily consulting fees related to the Transformation program (see Note 6 — Restructuring Costs). (iii) Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes. The Company does not currently provide asset information by reportable segment as it does not routinely evaluate the total asset position by segment.

Restructuring Costs

Restructuring Costs	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Restructuring Costs	Note 6 — Restructuring Costs In the fourth quarter of 2021, the Company initiated a three-year ‘Transformation program’ designed to enhance operations, optimize technology and align its real estate footprint to its new ways of working . During the fourth quarter of 2023, we revised the expected costs and savings under the program and we now expect the program to generate annual cost savings in excess of $ 425 million by the end of 2024. The program is expected to incur cumulative costs of approximately $ 995 million and capital expenditures of approximately $ 130 million, for a total investment of $ 1.125 billion. The main categories of charges will be in the following four areas: • Real estate rationalization — includes costs to align the real estate footprint to the new ways of working (hybrid work) and includes breakage fees and the impairment of right-of-use (‘ROU’) assets and other related leasehold assets. • Technology modernization — these charges are incurred in moving to common platforms and technologies, including migrating certain platforms and applications to the cloud. This category includes the impairment of technology assets that are duplicative or no longer revenue-producing, as well as costs for technology investments that do not qualify for capitalization. • Process optimization — these costs are incurred in the right-shoring strategy and automation of our operations, which includes optimizing resource deployment and appropriate colleague alignment. These costs include process and organizational design costs, severance and separation-related costs and temporary retention costs. • Other — other costs not included above including fees for professional services, other contract terminations not related to the above categories and supplier migration costs. Certain costs under the Transformation program are accounted for under ASC 420, Exit or Disposal Cost Obligation, and are included as restructuring costs in the condensed consolidated statements of comprehensive income. Other costs incurred under the Transformation program are included in transaction and transformation and were $ 119 million and $ 45 million for the three months ended March 31, 2024 and 2023, respectively. An analysis of total restructuring costs incurred under the Transformation program by category and by segment and corporate functions, from commencement to March 31, 2024, is as follows: HWC R&B Corporate Total 2021 Real estate rationalization $ — $ — $ 19 $ 19 Technology modernization — 5 — 5 Process optimization — — — — Other — — 2 2 2022 Real estate rationalization — — 79 79 Technology modernization — 3 16 19 Process optimization 1 — — 1 Other — — — — 2023 Real estate rationalization — — 46 46 Technology modernization 2 5 15 22 Process optimization — — — — Other — — — — 2024 Real estate rationalization — — 18 18 Technology modernization — — — — Process optimization — — — — Other — — — — Total Real estate rationalization — — 162 162 Technology modernization 2 13 31 46 Process optimization 1 — — 1 Other — — 2 2 Total $ 3 $ 13 $ 195 $ 211 A rollforward of the liability associated with cash-based charges related to restructuring costs associated with the Transformation program is as follows: Real estate rationalization Technology modernization Process optimization Other Total Balance at October 1, 2021 $ — $ — $ — $ — $ — Charges incurred — — — 2 2 Cash payments — — — ( 1 ) ( 1 ) Balance at December 31, 2021 — — — 1 1 Charges incurred 27 — 1 — 28 Cash payments ( 21 ) — ( 1 ) ( 1 ) ( 23 ) Balance at December 31, 2022 6 — — — 6 Charges incurred 22 8 — — 30 Cash payments ( 25 ) — — — ( 25 ) Balance at December 31, 2023 3 8 — — 11 Charges incurred 7 — — — 7 Cash payments ( 8 ) — — — ( 8 ) Balance at March 31, 2024 $ 2 $ 8 $ — $ — $ 10

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Note 7 — Income Taxes Provision for income taxes for the three months ended March 31, 2024 was $ 48 million compared to $ 50 million for the three months ended March 31, 2023. The effective tax rate was 19.9 % for the three months ended March 31, 2024 and 19.5 % for the three months ended March 31, 2023. These effective tax rates are calculated using extended values from our condensed consolidated statements of comprehensive income and are therefore more precise tax rates than can be calculated from rounded values. The current-year quarter’s effective tax rate is higher due to the distribution of geographical income. The Company recognizes deferred tax balances related to the undistributed earnings of subsidiaries when it expects that it will recover those undistributed earnings in a taxable manner, such as through receipt of dividends or sale of the investments. Historically, the Company has not provided taxes on cumulative earnings of its subsidiaries that have been reinvested indefinitely. As a result of its plans to restructure or distribute accumulated earnings of certain foreign operations, the Company has recorded an estimate of non-U.S. withholding and state income taxes. However, the Company asserts that the historical cumulative earnings of its other subsidiaries are reinvested indefinitely and therefore does not provide deferred tax liabilities on these amounts. The Company records valuation allowances against net deferred tax assets based on whether it is more likely than not that the deferred tax assets will be realized. We have liabilities for uncertain tax positions under ASC 740, Income Taxes of $ 52 million, excluding interest and penalties. The Company believes the outcomes that are reasonably possible within the next 12 months may result in a reduction in the liability for uncertain tax positions of approximately $ 1 million to $ 2 million, excluding interest and penalties.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note 8 — Goodwill and Other Intangible Assets The components of goodwill are outlined below for the three months ended March 31, 2024. HWC R&B Total Balance at December 31, 2023: Goodwill, gross $ 7,866 $ 2,821 $ 10,687 Accumulated impairment losses ( 130 ) ( 362 ) ( 492 ) Goodwill, net - December 31, 2023 7,736 2,459 10,195 Goodwill acquired 18 — 18 Foreign exchange ( 8 ) ( 19 ) ( 27 ) Balance at March 31, 2024: Goodwill, gross 7,876 2,802 10,678 Accumulated impairment losses ( 130 ) ( 362 ) ( 492 ) Goodwill, net - March 31, 2024 $ 7,746 $ 2,440 $ 10,186 Other Intangible Assets The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the three months ended March 31, 2024: Client relationships Software Trademark and trade name Other Total Balance at December 31, 2023: Intangible assets, gross $ 3,807 $ 729 $ 1,039 $ 63 $ 5,638 Accumulated amortization ( 2,514 ) ( 726 ) ( 342 ) ( 40 ) ( 3,622 ) Intangible assets, net - December 31, 2023 1,293 3 697 23 2,016 Intangible assets acquired 10 — — — 10 Amortization ( 48 ) — ( 11 ) ( 1 ) ( 60 ) Foreign exchange ( 6 ) — — — ( 6 ) Balance at March 31, 2024: Intangible assets, gross 3,797 734 1,038 63 5,632 Accumulated amortization ( 2,548 ) ( 731 ) ( 352 ) ( 41 ) ( 3,672 ) Intangible assets, net - March 31, 2024 $ 1,249 $ 3 $ 686 $ 22 $ 1,960 The weighted-average remaining life of amortizable intangible assets at March 31, 2024 was 11 .5 years. The table below reflects the future estimated amortization expense for amortizable intangible assets for the remainder of 2024 and for subsequent years: Amortization Remainder of 2024 $ 172 2025 212 2026 203 2027 199 2028 194 Thereafter 980 Total $ 1,960

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Note 9 — Derivative Financial Instruments We are exposed to certain foreign currency risks. Where possible, we identify exposures in our business that can be offset internally. Where no natural offset is identified, we may choose to enter into various derivative transactions. These instruments have the effect of reducing our exposure to unfavorable changes in foreign currency rates. The Company’s board of directors reviews and approves policies for managing this risk as summarized below. Additional information regarding our derivative financial instruments can be found in Note 11 — Fair Value Measurements and Note 17 — Accumulated Other Comprehensive Loss. Foreign Currency Risk Certain non-U.S. subsidiaries receive revenue and incur expenses in currencies other than their functional currency, and as a result, the foreign subsidiary’s functional currency revenue and/or expenses will fluctuate as the currency rates change. Additionally, the forecast Pounds sterling expenses of our London brokerage market operations may exceed their Pounds sterling revenue, and the entity with such operations may also hold significant foreign currency asset or liability positions in the condensed consolidated balance sheets. To reduce such variability, we use foreign exchange contracts to hedge against this currency risk. These derivatives were designated as hedging instruments and at March 31, 2024 and December 31, 2023 had total notional amounts of $ 118 million and $ 119 million, respectively, and had net asset fair values of $ 2 million at both periods presented . At March 31, 2024, the Company estimates, based on current exchange rates, there will be $ 1 million of net derivative gains on forward exchange rates reclassified from accumulated other comprehensive loss into earnings within the next twelve months as the forecast transactions affect earnings. At March 31, 2024, our longest outstanding maturity was 1.7 years. The effects of the material derivative instruments that are designated as hedging instruments on the condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023 are below. Amounts pertaining to the ineffective portion of hedging instruments and those excluded from effectiveness testing were immaterial for the three months ended March 31, 2024 and 2023. Three Months Ended March 31, Gain recognized in OCI (effective element) 2024 2023 Forward exchange contracts $ — $ 1 Location of (loss)/gain reclassified from Accumulated OCL into income (effective element) (Loss)/gain reclassified from Accumulated OCL into income (effective element) 2024 2023 Revenue $ ( 1 ) $ — Salaries and benefits 1 ( 1 ) $ — $ ( 1 ) The Company engages in intercompany borrowing and lending between subsidiaries, primarily through its in-house banking operations which give rise to foreign exchange exposures. The Company mitigates these risks through the use of short-term foreign currency forward and swap transactions that offset the underlying exposure created when the borrower and lender have different functional currencies. These derivatives are not generally designated as hedging instruments, and at March 31, 2024 and December 31, 2023, we had notional amounts of $ 1.2 billion at both periods presented, with net asset fair values of $ 3 million at both periods presented. Such derivatives typically mature within three months. The effects of derivatives that have not been designated as hedging instruments on the condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023 are as follows (see Note 16 — Other Income, Net for the net foreign currency impact on the Company’s condensed consolidated statements of comprehensive income which includes the results of the offset of underlying exposures): Gain recognized in income Three Months Ended Derivatives not designated as hedging instruments: Location of gain 2024 2023 Forward exchange contracts Other income, net $ 1 $ 8

Debt

Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Note 10 — Debt Current debt consists of the following: March 31, December 31, 3.600 % senior notes due 2024 $ 650 $ 650 $ 650 $ 650 Long-term debt consists of the following: March 31, December 31, Revolving $ 1.5 billion credit facility $ — $ — 4.400 % senior notes due 2026 548 548 4.650 % senior notes due 2027 745 745 4.500 % senior notes due 2028 598 598 2.950 % senior notes due 2029 727 726 5.350 % senior notes due 2033 741 741 6.125 % senior notes due 2043 272 272 5.050 % senior notes due 2048 395 395 3.875 % senior notes due 2049 542 542 5.900 % senior notes due 2054 739 — $ 5,307 $ 4,567 Senior Notes On March 5, 2024, the Company, together with its wholly-owned subsidiary, Willis North America Inc., as issuer, completed an offering of $ 750 million aggregate principal amount of 5.900 % senior notes due 2054 (‘2054 senior notes’). The effective interest rate of the 2054 senior notes is 6.00 %, which includes the impact of the discount upon issuance. The 2054 senior notes will mature on March 5, 2054 . Interest on the 2054 senior notes accrues from March 5, 2024 and will be paid in cash on March 5 and September 5 of each year, commencing on September 5, 2024 . The net proceeds from this offering, after deducting the underwriting discount and offering expenses, were approximately $ 739 million and will be used to fully repay the $ 650 million aggregate principal amount of the 3.600 % senior notes (which will mature during the second quarter of 2024) and related accrued interest, and for general corporate purposes. At March 31, 2024 and December 31, 2023, we were in compliance with all financial covenants.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 11 — Fair Value Measurements The Company has categorized its assets and liabilities that are measured at fair value on a recurring and non-recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows: • Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets; • Level 2: refers to fair values estimated using observable market-based inputs or unobservable inputs that are corroborated by market data; and • Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data. The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments: • Mutual funds and exchange-traded funds are classified as Level 1 because we use quoted market prices in active markets in determining the fair value of these securities. • Commingled funds are not leveled within the fair value hierarchy as the funds are valued at the net value of shares held as reported by the manager of the funds. These funds are not exchange-traded. • Hedge funds are not leveled within the fair value hierarchy as the fair values for these investments are estimated based on the net asset values derived from the latest audited financial statements or most recent capital account statements provided by the funds’ investment manager or third-party administrator, as a practical expedient. • Market values for our derivative instruments have been used to determine the fair values of forward and option foreign exchange contracts based on estimated amounts the Company would receive or have to pay to terminate the agreements, taking into account observable information about the current foreign currency forward rates. Such financial instruments are classified as Level 2. • Contingent consideration payable is classified as Level 3, and we estimate fair value based on the likelihood and timing of achieving the relevant milestones of each arrangement, applying a probability assessment to each of the potential outcomes, which at times includes the use of a Monte Carlo simulation and discounting the probability-weighted payout. Typically, milestones are based on revenue or earnings growth for the acquired business. The following tables present our assets and liabilities measured at fair value on a recurring basis at March 31, 2024 and December 31, 2023: Fair Value Measurements on a Recurring Basis at Balance Sheet Location Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds/exchange traded funds (i) Prepaid and other current assets and Other non-current assets $ 105 $ — $ — $ 105 Fiduciary assets 265 — — 265 Commingled funds (i) (ii) Other non-current assets — — — 10 Hedge funds (i) (iii) Other non-current assets — — — 8 Derivatives: Derivative financial instruments (iv) Prepaid and other current assets and Other non-current assets $ — $ 5 $ — $ 5 Liabilities: Contingent consideration: Contingent consideration (v) (vi) Other current liabilities and Other non-current liabilities $ — $ — $ 34 $ 34 Derivatives: Derivative financial instruments (iv) Other current liabilities and Other non-current liabilities $ — $ — $ — $ — Fair Value Measurements on a Recurring Basis at Balance Sheet Location Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds/exchange traded funds (i) Prepaid and other current assets and Other non-current assets $ 102 $ — $ — $ 102 Fiduciary assets 215 — — 215 Commingled funds (i) (ii) Other non-current assets — — — 9 Hedge funds (i) (iii) Other non-current assets — — — 8 Derivatives: Derivative financial instruments (iv) Prepaid and other current assets and Other non-current assets $ — $ 6 $ — $ 6 Liabilities: Contingent consideration: Contingent consideration (v) Other current liabilities and Other non-current liabilities $ — $ — $ 31 $ 31 Derivatives: Derivative financial instruments (iv) Other current liabilities and Other non-current liabilities $ — $ 1 $ — $ 1 (i) With the exception of the funds included in fiduciary assets, the majority of these balances are held as part of deferred compensation plans with related liabilities in other current liabilities and other non-current liabilities on the condensed consolidated balance sheets. (ii) Consists of the Towers Watson Global Equity Focus Fund, for which redemptions can occur on any business day, and require a minimum of one business day’s notice. (iii) Consists of the Towers Watson Alternative Credit Fund, for which the redemption period is generally quarterly, however requires a 50-day notice. (iv) See Note 9 — Derivative Financial Instruments for further information on our derivative investments. (v) Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The fair value weighted-average discount rates used in our material contingent consideration calculations were 13.00 % and 13.28 % at March 31, 2024 and December 31, 2023, respectively. The range of these discount rates was 11.00 % - 13.80 % at March 31, 2024. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable. (vi) Consideration due to be paid across multiple years until 2029. The following table summarizes the change in fair value of the Level 3 liabilities: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) March 31, 2024 Balance at December 31, 2023 $ 31 Obligations assumed 3 Payments — Realized and unrealized losses (i) 1 Foreign exchange ( 1 ) Balance at March 31, 2024 $ 34 (i) Realized and unrealized losses include accretion and adjustments to contingent consideration liabilities, which are included within Interest expense and Other operating expenses, respectively, on the condensed consolidated statements of comprehensive income. There were no significant transfers to or from Level 3 in the three months ended March 31, 2024. Fair value information about financial instruments not measured at fair value The following tables present our assets and liabilities not measured at fair value on a recurring basis at March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Carrying Value Fair Value Carrying Value Fair Value Assets: Long-term note receivable $ 73 $ 67 $ 74 $ 70 Liabilities: Current debt $ 650 $ 648 $ 650 $ 645 Long-term debt $ 5,307 $ 5,066 $ 4,567 $ 4,359 The carrying value of our revolving credit facility approximates its fair value. The fair values above, which exclude accrued interest, are not necessarily indicative of the amounts that the Company would realize upon disposition, nor do they indicate the Company’s intent or ability to dispose of the financial instruments. The fair values of our respective senior notes and long-term note receivable are considered Level 2 financial instruments as they are corroborated by observable market data.

Retirement Benefits

Retirement Benefits	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Retirement Benefits	Note 12 — Retirement Benefits Defined Benefit Plans WTW sponsors both qualified and non-qualified defined benefit pension plans throughout the world. The majority of our plan assets and obligations are in the U.S. and the U.K. We have also included disclosures related to defined benefit plans in certain other countries, including Canada, France, Germany, Switzerland and Ireland. Together, these disclosed funded and unfunded plans represent 98 % of WTW’s pension obligations and are disclosed herein. Components of Net Periodic Benefit (Income)/Cost for Defined Benefit Pension Plans The following table sets forth the components of net periodic benefit (income)/cost for the Company’s defined benefit pension plans for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 2023 U.S. U.K. Other U.S. U.K. Other Service cost $ 11 $ 1 $ 4 $ 14 $ 1 $ 3 Interest cost 49 28 7 49 29 7 Expected return on plan assets ( 76 ) ( 39 ) ( 10 ) ( 76 ) ( 39 ) ( 9 ) Amortization of net loss 9 14 — 3 12 — Amortization of prior service credit — ( 3 ) — — ( 3 ) — Net periodic benefit (income)/cost $ ( 7 ) $ 1 $ 1 $ ( 10 ) $ — $ 1 Employer Contributions to Defined Benefit Pension Plans The Company did no t make any contributions to its U.S. plans during the three months ended March 31, 2024 and currently does no t anticipate making contributions over the remainder of the fiscal year . The Company made contributions of $ 1 million to its U.K. plans for the three months ended March 31, 2024 and anticipates making additional contributions of $ 1 million for the remainder of the fiscal year. The Company made contributions of $ 9 million to its other plans for the three months ended March 31, 2024 and anticipates making additional contributions of $ 6 million for the remainder of the fiscal year. Defined Contribution Plans The Company made contributions to its defined contribution plans of $ 43 million and $ 40 million during the three months ended March 31, 2024 and 2023, respectively.

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	Note 13 — Leases The following table presents lease costs recorded on our condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 2023 Finance lease cost: Amortization of right-of-use assets $ 1 $ — Interest on lease liabilities — 1 Operating lease cost 42 34 Variable lease cost 14 12 Sublease income ( 5 ) ( 3 ) Total lease cost, net $ 52 $ 44 The total lease cost is recognized in different locations in our condensed consolidated statements of comprehensive income. Amortization of the finance lease ROU assets is included in depreciation, while the interest cost component of these finance leases is included in interest expense. All other costs are included in other operating expenses, with the exception of $ 15 million and $ 1 million incurred during the three months ended March 31, 2024 and 2023, respectively, that were included in restructuring costs (see Note 6 — Restructuring Costs) that primarily related to the acceleration of amortization of certain abandoned ROU assets and the payment of early termination fees.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 14 — Commitments and Contingencies Indemnification Agreements WTW has various agreements which provide that it may be obligated to indemnify the other party to the agreement with respect to certain matters. Generally, these indemnification provisions are included in contracts arising in the normal course of business and in connection with the purchase and sale of certain businesses, including the disposal of Willis Re. It is not possible to predict the maximum potential amount of future payments that may become due under these indemnification agreements because of the conditional nature of the Company’s obligations and the unique facts of each particular agreement. However, we do not believe that any potential liability that may arise from such indemnity provisions is probable or material. Legal Proceedings In the ordinary course of business, the Company is subject to various actual and potential claims, lawsuits and other proceedings. Some of the claims, lawsuits and other proceedings seek damages in amounts which could, if assessed, be significant. The Company also receives subpoenas in the ordinary course of business and, from time to time, receives requests for information in connection with governmental investigations. Errors and omissions claims, lawsuits, and other proceedings arising in the ordinary course of business are covered in part by professional indemnity or other appropriate insurance. The terms of this insurance vary by policy year. Regarding self-insured risks, the Company has established provisions which are believed to be adequate in light of current information and legal advice, or, in certain cases, where a range of loss exists, the Company accrues the minimum amount in the range if no amount within the range is a better estimate than any other amount. The Company adjusts such provisions from time to time according to developments. See Note 15 — Supplementary Information for Certain Balance Sheet Accounts for the amounts accrued at March 31, 2024 and December 31, 2023 in the condensed consolidated balance sheets. On the basis of current information, the Company does not expect that the actual claims, lawsuits and other proceedings to which it is subject, or potential claims, lawsuits, and other proceedings relating to matters of which it is aware, will ultimately have a material adverse effect on its financial condition, results of operations or liquidity. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation and disputes with insurance companies, it is possible that an adverse outcome or settlement in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in a particular quarterly or annual period. The Company provides for contingent liabilities based on ASC 450, Contingencies, when it is determined that a liability, inclusive of defense costs, is probable and reasonably estimable. The contingent liabilities recorded are primarily developed actuarially. Litigation is subject to many factors which are difficult to predict so there can be no assurance that in the event of a material unfavorable result in one or more claims, we will not incur material costs.

Supplementary Information for C

Supplementary Information for Certain Balance Sheet Accounts	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplementary Information for Certain Balance Sheet Accounts	Note 15 — Supplementary Information for Certain Balance Sheet Accounts Additional details of specific balance sheet accounts are detailed below. Deferred revenue and accrued expenses consist of the following: March 31, December 31, Accounts payable, accrued liabilities and deferred revenue $ 1,106 $ 1,073 Accrued discretionary and incentive compensation 266 795 Accrued vacation 183 150 Other employee-related liabilities 83 86 Total deferred revenue and accrued expenses $ 1,638 $ 2,104 Other current liabilities consist of the following: March 31, December 31, Dividends payable $ 108 $ 103 Income taxes payable 56 50 Interest payable 45 50 Deferred compensation plan liabilities 12 16 Contingent and deferred consideration on acquisitions 24 7 Accrued retirement benefits 31 31 Payroll and other benefits-related liabilities 267 166 Other taxes payable 63 78 Third-party commissions 108 106 Other current liabilities 53 71 Total other current liabilities $ 767 $ 678 Provision for liabilities consists of the following: March 31, December 31, Claims, lawsuits and other proceedings $ 313 $ 306 Other provisions 64 59 Total provision for liabilities $ 377 $ 365

Other Income, Net

Other Income, Net	3 Months Ended
	Mar. 31, 2024
Other Income and Expenses [Abstract]
Other Income, Net	Note 16 — Other Income, Net Other income, net consists of the following: Three Months Ended 2024 2023 Net periodic pension and postretirement benefit credits $ 22 $ 28 Interest in earnings of associates and other investments — 1 Foreign exchange gain/(loss) (i) 3 ( 5 ) Other 1 1 Other income, net $ 26 $ 25 (i) Includes the offsetting effects of the Company's foreign currency hedging program. See Note 9 — Derivative Financial Instruments.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Accumulated Other Comprehensive Loss	Note 17 — Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss, net of non-controlling interests, and net of tax are provided in the following table for the three months ended March 31, 2024 and 2023. This table excludes amounts attributable to non-controlling interests, which are not material for further disclosure. Foreign currency Derivative (i) Defined pension and Total 2024 2023 2024 2023 2024 2023 2024 2023 Balance at December 31, 2023 and 2022, respectively $ ( 816 ) $ ( 987 ) $ 11 $ 9 $ ( 2,051 ) $ ( 1,643 ) $ ( 2,856 ) $ ( 2,621 ) Other comprehensive (loss)/income before ( 63 ) 43 — 2 — ( 1 ) ( 63 ) 44 Loss reclassified from accumulated other 5 and $ 3 , respectively) — — — — 14 9 14 9 Net current-period other comprehensive (loss)/income ( 63 ) 43 — 2 14 8 ( 49 ) 53 Balance at March 31, 2024 and 2023, respectively $ ( 879 ) $ ( 944 ) $ 11 $ 11 $ ( 2,037 ) $ ( 1,635 ) $ ( 2,905 ) $ ( 2,568 ) (i) Reclassification adjustments from accumulated other comprehensive loss related to derivative instruments are included in Revenue and Salaries and benefits in the accompanying condensed consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the derivative settlements.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Note 18 — Earnings Per Share Basic and diluted earnings per share are calculated by dividing net income attributable to WTW by the average number of ordinary shares outstanding during each period. The computation of diluted earnings per share reflects the potential dilution that could occur if dilutive securities and other contracts to issue shares were exercised or converted into shares or resulted in the issuance of shares that then shared in the net income of the Company. At March 31, 2024 and 2023, there were 0.5 million restricted performance-based stock units outstanding at each period presented and 0.4 million restricted time-based stock units outstanding at each period presented. The Company had no time-based share options outstanding at March 31, 2024; time-based share options were immaterial at March 31, 2023. There were no performance-based options outstanding at March 31, 2024 and 2023. Basic and diluted earnings per share are as follows: Three Months Ended March 31, 2024 2023 Net income attributable to WTW $ 190 $ 203 Basic average number of shares outstanding 103 107 Dilutive effect of potentially issuable shares 1 1 Diluted average number of shares outstanding 104 108 Basic earnings per share $ 1.84 $ 1.89 Dilutive effect of potentially issuable shares ( 0.01 ) ( 0.01 ) Diluted earnings per share $ 1.83 $ 1.88 There were no anti-dilutive restricted stock units or anti-dilutive options for the three months ended March 31, 2024 and 2023.

Supplemental Disclosures of Cas

Supplemental Disclosures of Cash Flow Information	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Cash Flow Information	Note 19 — Supplemental Disclosures of Cash Flow Information Supplemental disclosures regarding cash flow information are as follows: Three months ended March 31, 2024 2023 Supplemental disclosures of cash flow information: Cash and cash equivalents $ 1,893 $ 1,135 Fiduciary funds (included in fiduciary assets) 3,358 3,227 Total cash, cash equivalents and restricted cash $ 5,251 $ 4,362 Increase/(decrease) in cash, cash equivalents and other restricted cash $ 487 $ ( 130 ) Increase/(decrease) in fiduciary funds 1,019 ( 250 ) Total $ 1,506 $ ( 380 )

Basis of Presentation and Rec_2

Basis of Presentation and Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited quarterly condensed consolidated financial statements of WTW and our subsidiaries are presented in accordance with the rules and regulations of the SEC for quarterly reports on Form 10-Q and therefore certain footnote disclosures have been condensed or omitted from these financial statements as they are not required for interim reporting under U.S. GAAP. In the opinion of management, these condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, which are necessary for a fair presentation of the condensed consolidated financial statements and results for the interim periods. All intercompany accounts and transactions have been eliminated in consolidation. The condensed consolidated financial statements should be read together with the Company’s Annual Report on Form 10-K, filed with the SEC on February 22, 2024, and may be accessed via EDGAR on the SEC’s web site at www.sec.gov. The results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results that can be expected for the entire year. The Company experiences seasonal fluctuations of its revenue. Revenue is typically higher during the Company’s first and fourth quarters due primarily to the timing of broking-related activities. The results reflect certain estimates and assumptions made by management, including those estimates used in calculating acquisition consideration and fair value of tangible and intangible assets and acquisition-related liabilities, professional liability claims, estimated bonuses, valuation of billed and unbilled receivables, and anticipated tax liabilities that affect the amounts reported in the condensed consolidated financial statements and related notes.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , which is intended to improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information within the income tax rate reconciliation and income taxes paid disclosures. It also includes certain other amendments intended to improve the effectiveness of income tax disclosures. Specifically, this ASU requires a tabular income tax rate reconciliation using both percentages and amounts disaggregated into specific categories with certain reconciling items at or above 5% of the statutory tax, further disaggregated by its nature and/or jurisdiction. Additionally, income taxes paid will be required to be presented by federal, state, local and foreign jurisdictions, including amounts paid to individual jurisdictions representing 5% or more of the total income taxes paid. This ASU becomes effective for the Company on January 1, 2025, with early adoption permitted. The guidance is applied prospectively, with the option for retrospective application. The Company does not plan to early-adopt this ASU and is assessing the expected impact on its condensed consolidated financial statements. In March 2024, the SEC adopted final rules on the enhancement and standardization of climate-related disclosures for investors. The rules require disclosure of certain climate-related information in registration statements and annual reports on Form 10-K. For example, the rules require the notes to the financial statements to include disclosure regarding the effects of severe weather events and other natural conditions, subject to certain materiality thresholds. Additionally, the rules also require certain other disclosures outside of the financial statements. Among other things, these requirements include Scope 1 (direct) and Scope 2 (indirect from purchased energy) greenhouse gas (‘GHG’) emissions, if material, which will be subject to assurance requirements that will be phased in, as well as governance, oversight and risk management disclosures, which include any transition plan adopted to manage material transition risk, and material climate targets and goals. The rules become effective in phases, currently beginning with any material current-year effects of severe weather events and other natural conditions and the more qualitative disclosures being required for inclusion in the Company’s 2025 Form 10-K, and some of the other more quantitative disclosures being required for the 2026 Form 10-K. While the disclosures are meant to cover the same periods in the financial statements, the requirements may be adopted on a prospective basis beginning with 2025. The Scope 1 and Scope 2 GHG emissions disclosures, which are required for the 2026 fiscal year, allow for additional time but must be filed by the due date of the second quarterly report on Form 10-Q or by amending the Form 10-K by that same deadline. Third-party limited assurance of the GHG emissions disclosures is required for the Company’s 2029 Form 10-K and reasonable assurance is required for the Company’s 2033 Form 10-K. Following a number of legal challenges to the final rule that have been consolidated for review in the U.S. Court of Appeals for the Eighth Circuit, the SEC has voluntarily stayed the newly-released climate rules pending the completion of judicial review of such consolidated petitions to avoid regulatory uncertainty for companies subject to the rule while the litigation proceeds. The Company is monitoring the outcome of the litigation and will provide the required disclosures if and when required. Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , which is intended to improve reportable segment disclosure requirements through enhanced disclosures about significant segment expenses. Among other amendments, this ASU creates a ‘significant expense principle,’ and adds required disclosures of significant expenses for each reportable segment, as well as certain other disclosures to help investors understand how the chief operating decision maker (‘CODM’) evaluates segment expenses and operating results. In addition, this ASU requires for interim periods all disclosures about a reportable segment’s profit or loss and assets under ASC 280, Segment Reporting that had previously only been provided annually (e.g., interest income and expense, depreciation and amortization expense). The annual requirements of this ASU became effective for the Company on January 1, 2024, at which time it was adopted; the Company will include the new disclosures in our Annual Report on Form 10-K for the year ended December 31, 2024, as required. New interim disclosures are required for fiscal years beginning January 1, 2025 and will be included at that time.
Other Legislation	Other Legislation Inflation Reduction Act The Inflation Reduction Act (the ‘IRA’) was enacted into law on August 16, 2022 and certain portions of the IRA became effective January 1, 2023. The IRA introduced, among other provisions, a share repurchase excise tax and a new Corporate Alternative Minimum Tax (‘CAMT’) which imposes a 15% tax on the adjusted financial statement income of ‘applicable corporations’. New rules issued in the proposed regulations issued on April 9, 2024 apply to share repurchases after April 12, 2024. The Company does not expect the excise tax or CAMT to have a significant impact on its condensed consolidated financial statements. Pillar Two On October 8, 2021, the Organisation for Economic Co-operation and Development (‘OECD’) announced an international agreement with more than 140 countries to implement a two-pillar solution to address tax challenges arising from the digitalization of the economy. The agreement introduced rules that would result in the reallocation of certain taxing rights over multinational companies from their home countries to the markets where they have business activities and earn profits, regardless of physical presence (‘Pillar One’) and introduced a global corporate minimum tax of 15% for certain large multinational companies starting in 2024 (‘Pillar Two’). On December 20, 2021, the OECD/G20 Inclusive Framework on Base Erosion and Profit Shifting released the Model Global Anti-Base Erosion (‘GloBE’) rules (the ‘OECD Model Rules’) under Pillar Two. On December 12, 2022, E.U. member states reached an agreement to implement Pillar Two and this requires E.U. member states to enact domestic legislation to put Pillar Two into effect. In 2023, many E.U. countries enacted the necessary legislation (based on the OECD Model Rules) to implement Pillar Two in 2024. Ireland, in particular, enacted Pillar Two by signing Finance (No. 2) Bill 2023 into law in December 2023. Other countries and territories have indicated they will introduce Pillar Two beginning in 2025. While we do not anticipate that this legislation will have a material impact on our tax provision or effective tax rate, we continue to monitor evolving tax legislation in the jurisdictions in which we operate.
Fair Value of Financial Instruments	The Company has categorized its assets and liabilities that are measured at fair value on a recurring and non-recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows: • Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets; • Level 2: refers to fair values estimated using observable market-based inputs or unobservable inputs that are corroborated by market data; and • Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data. The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments: • Mutual funds and exchange-traded funds are classified as Level 1 because we use quoted market prices in active markets in determining the fair value of these securities. • Commingled funds are not leveled within the fair value hierarchy as the funds are valued at the net value of shares held as reported by the manager of the funds. These funds are not exchange-traded. • Hedge funds are not leveled within the fair value hierarchy as the fair values for these investments are estimated based on the net asset values derived from the latest audited financial statements or most recent capital account statements provided by the funds’ investment manager or third-party administrator, as a practical expedient. • Market values for our derivative instruments have been used to determine the fair values of forward and option foreign exchange contracts based on estimated amounts the Company would receive or have to pay to terminate the agreements, taking into account observable information about the current foreign currency forward rates. Such financial instruments are classified as Level 2. • Contingent consideration payable is classified as Level 3, and we estimate fair value based on the likelihood and timing of achieving the relevant milestones of each arrangement, applying a probability assessment to each of the potential outcomes, which at times includes the use of a Monte Carlo simulation and discounting the probability-weighted payout. Typically, milestones are based on revenue or earnings growth for the acquired business.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents revenue by service offering and segment, as well as a reconciliation to total revenue for the three months ended March 31, 2024 and 2023. Along with reimbursable expenses and other, total revenue by service offering represents our revenue from customer contracts. Three Months Ended March 31, HWC R&B Corporate (i) Total 2024 2023 2024 2023 2024 2023 2024 2023 Broking $ 335 $ 289 $ 742 $ 691 $ — $ 5 $ 1,077 $ 985 Consulting 662 661 104 98 1 4 767 763 Outsourced administration 266 262 30 29 — — 296 291 Other 64 69 71 67 — — 135 136 Total revenue by service offering 1,327 1,281 947 885 1 9 2,275 2,175 Reimbursable expenses and other (i) 17 15 3 3 — 10 20 28 Total revenue from customer contracts $ 1,344 $ 1,296 $ 950 $ 888 $ 1 $ 19 $ 2,295 $ 2,203 Interest and other income 9 6 31 19 6 16 46 41 Total revenue $ 1,353 $ 1,302 $ 981 $ 907 $ 7 $ 35 $ 2,341 $ 2,244 (i) Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions. Interest and other income is included in segment revenue and total revenue, however it has been presented separately in the above tables because it does not arise directly from contracts with customers. The significant components of interest and other income are as follows for the periods presented above: Three Months Ended March 31, HWC R&B Corporate Total 2024 2023 2024 2023 2024 2023 2024 2023 Book-of-business settlements $ — $ — $ 2 $ 7 $ — $ — $ 2 $ 7 Interest income 9 5 28 12 6 15 43 32 Other income — 1 1 — — 1 1 2 Total interest and other income $ 9 $ 6 $ 31 $ 19 $ 6 $ 16 $ 46 $ 41 As a result of the cessation of the co-broking agreement, (see Note 3 — Acquisitions and Divestitures) interest income associated with fiduciary funds is now allocated more directly to the Risk and Broking segment beginning in the third quarter of 2023. These amounts were previously allocated to the Corporate segment following the disposal of Willis Re. The following table presents revenue from service offerings by the geography where our work was performed for the three months ended March 31, 2024 and 2023. The reconciliation to total revenue on our condensed consolidated statements of comprehensive income and to segment revenue is shown in the table above. Three Months Ended March 31, HWC R&B Corporate Total 2024 2023 2024 2023 2024 2023 2024 2023 North America $ 840 $ 823 $ 306 $ 291 $ — $ 1 $ 1,146 $ 1,115 Europe 372 346 511 471 1 7 884 824 International 115 112 130 123 — 1 245 236 Total revenue by geography $ 1,327 $ 1,281 $ 947 $ 885 $ 1 $ 9 $ 2,275 $ 2,175
Contract with Customer, Asset and Liability	The Company reports accounts receivable, net on the condensed consolidated balance sheets, which includes billed and unbilled receivables and current contract assets. In addition to accounts receivable, net, the Company had the following non-current contract assets and deferred revenue balances at March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Billed receivables, net of allowance for doubtful accounts of $ 39 million and $ 34 million $ 1,511 $ 1,581 Unbilled receivables 537 491 Current contract assets 382 500 Accounts receivable, net $ 2,430 $ 2,572 Non-current accounts receivable, net $ 19 $ 19 Non-current contract assets $ 925 $ 909 Deferred revenue $ 757 $ 677
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	In addition, in accordance with ASC 606, Revenue From Contracts With Customers (‘ASC 606’), the Company has elected not to disclose the remaining performance obligations when one or both of the following circumstances apply: • Performance obligations which are part of a contract that has an original expected duration of less than one year , and • Performance obligations satisfied in accordance with ASC 606-10-55-18 (‘right to invoice’). Remainder of 2024 2025 2026 onward Total Revenue expected to be recognized on contracts as of March 31, 2024 $ 403 $ 396 $ 511 $ 1,310

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table presents segment revenue and segment operating income for our reportable segments for the three months ended March 31, 2024 and 2023. Three Months Ended March 31, HWC R&B Total 2024 2023 2024 2023 2024 2023 Segment revenue $ 1,336 $ 1,287 $ 978 $ 904 $ 2,314 $ 2,191 Segment operating income $ 336 $ 309 $ 203 $ 180 $ 539 $ 489
Net Operating Income of the Reported Segments	The following table presents reconciliations of the information reported by segment to the Company’s condensed consolidated statements of comprehensive income amounts reported for the three months ended March 31, 2024 and 2023. Three Months Ended 2024 2023 Revenue: Total segment revenue $ 2,314 $ 2,191 Reimbursable expenses and other 27 53 Revenue $ 2,341 $ 2,244 Total segment operating income $ 539 $ 489 Amortization ( 60 ) ( 71 ) Restructuring costs (i) ( 18 ) ( 3 ) Transaction and transformation (ii) ( 125 ) ( 59 ) Unallocated, net (iii) ( 56 ) ( 71 ) Income from operations 280 285 Interest expense ( 64 ) ( 54 ) Other income, net 26 25 Income from operations before income taxes $ 242 $ 256 (i) See Note 6 — Restructuring Costs for the composition of costs for 2024 and 2023. (ii) In 2024 and 2023, in addition to legal fees and other transaction costs, includes primarily consulting fees related to the Transformation program (see Note 6 — Restructuring Costs). (iii) Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.

Restructuring Costs (Tables)

Restructuring Costs (Tables)	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Summary of Total Restructuring Costs	An analysis of total restructuring costs incurred under the Transformation program by category and by segment and corporate functions, from commencement to March 31, 2024, is as follows: HWC R&B Corporate Total 2021 Real estate rationalization $ — $ — $ 19 $ 19 Technology modernization — 5 — 5 Process optimization — — — — Other — — 2 2 2022 Real estate rationalization — — 79 79 Technology modernization — 3 16 19 Process optimization 1 — — 1 Other — — — — 2023 Real estate rationalization — — 46 46 Technology modernization 2 5 15 22 Process optimization — — — — Other — — — — 2024 Real estate rationalization — — 18 18 Technology modernization — — — — Process optimization — — — — Other — — — — Total Real estate rationalization — — 162 162 Technology modernization 2 13 31 46 Process optimization 1 — — 1 Other — — 2 2 Total $ 3 $ 13 $ 195 $ 211
Rollforward of Liability Associated with Cash-based Charges	A rollforward of the liability associated with cash-based charges related to restructuring costs associated with the Transformation program is as follows: Real estate rationalization Technology modernization Process optimization Other Total Balance at October 1, 2021 $ — $ — $ — $ — $ — Charges incurred — — — 2 2 Cash payments — — — ( 1 ) ( 1 ) Balance at December 31, 2021 — — — 1 1 Charges incurred 27 — 1 — 28 Cash payments ( 21 ) — ( 1 ) ( 1 ) ( 23 ) Balance at December 31, 2022 6 — — — 6 Charges incurred 22 8 — — 30 Cash payments ( 25 ) — — — ( 25 ) Balance at December 31, 2023 3 8 — — 11 Charges incurred 7 — — — 7 Cash payments ( 8 ) — — — ( 8 ) Balance at March 31, 2024 $ 2 $ 8 $ — $ — $ 10

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Goodwill	The components of goodwill are outlined below for the three months ended March 31, 2024. HWC R&B Total Balance at December 31, 2023: Goodwill, gross $ 7,866 $ 2,821 $ 10,687 Accumulated impairment losses ( 130 ) ( 362 ) ( 492 ) Goodwill, net - December 31, 2023 7,736 2,459 10,195 Goodwill acquired 18 — 18 Foreign exchange ( 8 ) ( 19 ) ( 27 ) Balance at March 31, 2024: Goodwill, gross 7,876 2,802 10,678 Accumulated impairment losses ( 130 ) ( 362 ) ( 492 ) Goodwill, net - March 31, 2024 $ 7,746 $ 2,440 $ 10,186
Changes in the Net Carrying Amount of the Components of Finite-Lived Intangible Assets	The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the three months ended March 31, 2024: Client relationships Software Trademark and trade name Other Total Balance at December 31, 2023: Intangible assets, gross $ 3,807 $ 729 $ 1,039 $ 63 $ 5,638 Accumulated amortization ( 2,514 ) ( 726 ) ( 342 ) ( 40 ) ( 3,622 ) Intangible assets, net - December 31, 2023 1,293 3 697 23 2,016 Intangible assets acquired 10 — — — 10 Amortization ( 48 ) — ( 11 ) ( 1 ) ( 60 ) Foreign exchange ( 6 ) — — — ( 6 ) Balance at March 31, 2024: Intangible assets, gross 3,797 734 1,038 63 5,632 Accumulated amortization ( 2,548 ) ( 731 ) ( 352 ) ( 41 ) ( 3,672 ) Intangible assets, net - March 31, 2024 $ 1,249 $ 3 $ 686 $ 22 $ 1,960
Schedule of Future Estimated Amortization Expense for Amortizable Intangible Assets	The table below reflects the future estimated amortization expense for amortizable intangible assets for the remainder of 2024 and for subsequent years: Amortization Remainder of 2024 $ 172 2025 212 2026 203 2027 199 2028 194 Thereafter 980 Total $ 1,960

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Designated [Member]
Schedule of Derivative Instruments Designated/Nondesignated As Hedging Instrument Effect on Condensed Consolidated Statements of Comprehensive Income	The effects of the material derivative instruments that are designated as hedging instruments on the condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023 are below. Three Months Ended March 31, Gain recognized in OCI (effective element) 2024 2023 Forward exchange contracts $ — $ 1 Location of (loss)/gain reclassified from Accumulated OCL into income (effective element) (Loss)/gain reclassified from Accumulated OCL into income (effective element) 2024 2023 Revenue $ ( 1 ) $ — Salaries and benefits 1 ( 1 ) $ — $ ( 1 )
Nondesignated [Member]
Schedule of Derivative Instruments Designated/Nondesignated As Hedging Instrument Effect on Condensed Consolidated Statements of Comprehensive Income	The effects of derivatives that have not been designated as hedging instruments on the condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023 are as follows (see Note 16 — Other Income, Net for the net foreign currency impact on the Company’s condensed consolidated statements of comprehensive income which includes the results of the offset of underlying exposures): Gain recognized in income Three Months Ended Derivatives not designated as hedging instruments: Location of gain 2024 2023 Forward exchange contracts Other income, net $ 1 $ 8

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Current and Long-term Debt	Current debt consists of the following: March 31, December 31, 3.600 % senior notes due 2024 $ 650 $ 650 $ 650 $ 650 Long-term debt consists of the following: March 31, December 31, Revolving $ 1.5 billion credit facility $ — $ — 4.400 % senior notes due 2026 548 548 4.650 % senior notes due 2027 745 745 4.500 % senior notes due 2028 598 598 2.950 % senior notes due 2029 727 726 5.350 % senior notes due 2033 741 741 6.125 % senior notes due 2043 272 272 5.050 % senior notes due 2048 395 395 3.875 % senior notes due 2049 542 542 5.900 % senior notes due 2054 739 — $ 5,307 $ 4,567

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our assets and liabilities measured at fair value on a recurring basis at March 31, 2024 and December 31, 2023: Fair Value Measurements on a Recurring Basis at Balance Sheet Location Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds/exchange traded funds (i) Prepaid and other current assets and Other non-current assets $ 105 $ — $ — $ 105 Fiduciary assets 265 — — 265 Commingled funds (i) (ii) Other non-current assets — — — 10 Hedge funds (i) (iii) Other non-current assets — — — 8 Derivatives: Derivative financial instruments (iv) Prepaid and other current assets and Other non-current assets $ — $ 5 $ — $ 5 Liabilities: Contingent consideration: Contingent consideration (v) (vi) Other current liabilities and Other non-current liabilities $ — $ — $ 34 $ 34 Derivatives: Derivative financial instruments (iv) Other current liabilities and Other non-current liabilities $ — $ — $ — $ — Fair Value Measurements on a Recurring Basis at Balance Sheet Location Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds/exchange traded funds (i) Prepaid and other current assets and Other non-current assets $ 102 $ — $ — $ 102 Fiduciary assets 215 — — 215 Commingled funds (i) (ii) Other non-current assets — — — 9 Hedge funds (i) (iii) Other non-current assets — — — 8 Derivatives: Derivative financial instruments (iv) Prepaid and other current assets and Other non-current assets $ — $ 6 $ — $ 6 Liabilities: Contingent consideration: Contingent consideration (v) Other current liabilities and Other non-current liabilities $ — $ — $ 31 $ 31 Derivatives: Derivative financial instruments (iv) Other current liabilities and Other non-current liabilities $ — $ 1 $ — $ 1 (i) With the exception of the funds included in fiduciary assets, the majority of these balances are held as part of deferred compensation plans with related liabilities in other current liabilities and other non-current liabilities on the condensed consolidated balance sheets. (ii) Consists of the Towers Watson Global Equity Focus Fund, for which redemptions can occur on any business day, and require a minimum of one business day’s notice. (iii) Consists of the Towers Watson Alternative Credit Fund, for which the redemption period is generally quarterly, however requires a 50-day notice. (iv) See Note 9 — Derivative Financial Instruments for further information on our derivative investments. (v) Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The fair value weighted-average discount rates used in our material contingent consideration calculations were 13.00 % and 13.28 % at March 31, 2024 and December 31, 2023, respectively. The range of these discount rates was 11.00 % - 13.80 % at March 31, 2024. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable. (vi) Consideration due to be paid across multiple years until 2029.
Schedule of Change in Fair Value of Level 3 Liabilities	The following table summarizes the change in fair value of the Level 3 liabilities: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) March 31, 2024 Balance at December 31, 2023 $ 31 Obligations assumed 3 Payments — Realized and unrealized losses (i) 1 Foreign exchange ( 1 ) Balance at March 31, 2024 $ 34 (i) Realized and unrealized losses include accretion and adjustments to contingent consideration liabilities, which are included within Interest expense and Other operating expenses, respectively, on the condensed consolidated statements of comprehensive income.
Schedule of Assets and Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis	The following tables present our assets and liabilities not measured at fair value on a recurring basis at March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Carrying Value Fair Value Carrying Value Fair Value Assets: Long-term note receivable $ 73 $ 67 $ 74 $ 70 Liabilities: Current debt $ 650 $ 648 $ 650 $ 645 Long-term debt $ 5,307 $ 5,066 $ 4,567 $ 4,359

Retirement Benefits (Tables)

Retirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Schedule of Net Periodic Benefit Cost	The following table sets forth the components of net periodic benefit (income)/cost for the Company’s defined benefit pension plans for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 2023 U.S. U.K. Other U.S. U.K. Other Service cost $ 11 $ 1 $ 4 $ 14 $ 1 $ 3 Interest cost 49 28 7 49 29 7 Expected return on plan assets ( 76 ) ( 39 ) ( 10 ) ( 76 ) ( 39 ) ( 9 ) Amortization of net loss 9 14 — 3 12 — Amortization of prior service credit — ( 3 ) — — ( 3 ) — Net periodic benefit (income)/cost $ ( 7 ) $ 1 $ 1 $ ( 10 ) $ — $ 1

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Schedule of Lease Costs Recorded in Condensed Consolidated Statements of Comprehensive Income	The following table presents lease costs recorded on our condensed consolidated statements of comprehensive income for the three months ended March 31, 2024 and 2023: Three Months Ended March 31, 2024 2023 Finance lease cost: Amortization of right-of-use assets $ 1 $ — Interest on lease liabilities — 1 Operating lease cost 42 34 Variable lease cost 14 12 Sublease income ( 5 ) ( 3 ) Total lease cost, net $ 52 $ 44

Supplementary Information for_2

Supplementary Information for Certain Balance Sheet Accounts (Tables)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred Revenue and Accrued Expenses	Deferred revenue and accrued expenses consist of the following: March 31, December 31, Accounts payable, accrued liabilities and deferred revenue $ 1,106 $ 1,073 Accrued discretionary and incentive compensation 266 795 Accrued vacation 183 150 Other employee-related liabilities 83 86 Total deferred revenue and accrued expenses $ 1,638 $ 2,104
Schedule of Other Current Liabilities	Other current liabilities consist of the following: March 31, December 31, Dividends payable $ 108 $ 103 Income taxes payable 56 50 Interest payable 45 50 Deferred compensation plan liabilities 12 16 Contingent and deferred consideration on acquisitions 24 7 Accrued retirement benefits 31 31 Payroll and other benefits-related liabilities 267 166 Other taxes payable 63 78 Third-party commissions 108 106 Other current liabilities 53 71 Total other current liabilities $ 767 $ 678
Provisions for Liabilities	Provision for liabilities consists of the following: March 31, December 31, Claims, lawsuits and other proceedings $ 313 $ 306 Other provisions 64 59 Total provision for liabilities $ 377 $ 365

Other Income, Net (Tables)

Other Income, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Income	Other income, net consists of the following: Three Months Ended 2024 2023 Net periodic pension and postretirement benefit credits $ 22 $ 28 Interest in earnings of associates and other investments — 1 Foreign exchange gain/(loss) (i) 3 ( 5 ) Other 1 1 Other income, net $ 26 $ 25 (i) Includes the offsetting effects of the Company's foreign currency hedging program. See Note 9 — Derivative Financial Instruments.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive loss, net of non-controlling interests, and net of tax are provided in the following table for the three months ended March 31, 2024 and 2023. This table excludes amounts attributable to non-controlling interests, which are not material for further disclosure. Foreign currency Derivative (i) Defined pension and Total 2024 2023 2024 2023 2024 2023 2024 2023 Balance at December 31, 2023 and 2022, respectively $ ( 816 ) $ ( 987 ) $ 11 $ 9 $ ( 2,051 ) $ ( 1,643 ) $ ( 2,856 ) $ ( 2,621 ) Other comprehensive (loss)/income before ( 63 ) 43 — 2 — ( 1 ) ( 63 ) 44 Loss reclassified from accumulated other 5 and $ 3 , respectively) — — — — 14 9 14 9 Net current-period other comprehensive (loss)/income ( 63 ) 43 — 2 14 8 ( 49 ) 53 Balance at March 31, 2024 and 2023, respectively $ ( 879 ) $ ( 944 ) $ 11 $ 11 $ ( 2,037 ) $ ( 1,635 ) $ ( 2,905 ) $ ( 2,568 ) (i) Reclassification adjustments from accumulated other comprehensive loss related to derivative instruments are included in Revenue and Salaries and benefits in the accompanying condensed consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the derivative settlements.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	Basic and diluted earnings per share are as follows: Three Months Ended March 31, 2024 2023 Net income attributable to WTW $ 190 $ 203 Basic average number of shares outstanding 103 107 Dilutive effect of potentially issuable shares 1 1 Diluted average number of shares outstanding 104 108 Basic earnings per share $ 1.84 $ 1.89 Dilutive effect of potentially issuable shares ( 0.01 ) ( 0.01 ) Diluted earnings per share $ 1.83 $ 1.88

Supplemental Disclosures of C_2

Supplemental Disclosures of Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures Regarding Cash Flow Information and Non-cash Flow Investing and Financing Activities	Supplemental disclosures regarding cash flow information are as follows: Three months ended March 31, 2024 2023 Supplemental disclosures of cash flow information: Cash and cash equivalents $ 1,893 $ 1,135 Fiduciary funds (included in fiduciary assets) 3,358 3,227 Total cash, cash equivalents and restricted cash $ 5,251 $ 4,362 Increase/(decrease) in cash, cash equivalents and other restricted cash $ 487 $ ( 130 ) Increase/(decrease) in fiduciary funds 1,019 ( 250 ) Total $ 1,506 $ ( 380 )

Nature of Operations (Details)

Nature of Operations (Details)	Mar. 31, 2024 Employee Country
Minority Interest [Line Items]
Number of employees employed | Employee	48,000
Number of countries in which entity operates (more than 140) | Country	140

Basis of Presentation and Rec_3

Basis of Presentation and Recent Accounting Pronouncements (Details)	Mar. 31, 2024 Country
Accounting Policies [Abstract]
Number of countries in which entity operates (more than 140)	140

Acquisitions and Divestitures -

Acquisitions and Divestitures - (Additional Information) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Business Combinations [Abstract]
Acquisitions, cash payment	$ 24
Contingent consideration fair value	$ 3

Acquisitions and Divestitures_2

Acquisitions and Divestitures - Willis Re Divestiture (Details) - Willis Re [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended				6 Months Ended
	Oct. 31, 2023	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2023	Dec. 01, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total consideration received from sale of subsidiary							$ 3,250
Gain on disposal			$ 5
Value of remaining settlement amount	$ 11
Transition Services Agreement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fees earned under service agreement		$ 6			$ 9
Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Earnout receivable in cash in 2025							$ 750
Gallagher [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Value of obligation in initial transfer				$ 74		$ 74
Value of receivables in initial transfer				26		26
Cash outflow of cash and non-fiduciary cash related to settlement						$ 916
Fiduciary assets transferred				4,500
Gallagher [Member] | Non-Fiduciary Cash [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash outflow of cash and non-fiduciary cash related to settlement				48
Gallagher [Member] | Fiduciary Cash [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash outflow of cash and non-fiduciary cash related to settlement				$ 868

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 2,295	$ 2,203
Reimbursable expenses and other	[1]	20	28
Interest and other income		46	41
Total revenue		2,341	2,244
HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,344	1,296
Reimbursable expenses and other	[1]	17	15
Interest and other income		9	6
Total revenue		1,353	1,302
R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		950	888
Reimbursable expenses and other	[1]	3	3
Interest and other income		31	19
Total revenue		981	907
Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	1	19
Reimbursable expenses and other	[1]	0	10
Interest and other income	[1]	6	16
Total revenue	[1]	7	35
Broking [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,077	985
Broking [Member] | HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		335	289
Broking [Member] | R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		742	691
Broking [Member] | Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	0	5
Consulting [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		767	763
Consulting [Member] | HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		662	661
Consulting [Member] | R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		104	98
Consulting [Member] | Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	1	4
Outsourced administration [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		296	291
Outsourced administration [Member] | HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		266	262
Outsourced administration [Member] | R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		30	29
Outsourced administration [Member] | Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	0	0
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		135	136
Other [Member] | HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		64	69
Other [Member] | R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		71	67
Other [Member] | Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	0	0
Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		2,275	2,175
Service | HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,327	1,281
Service | R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		947	885
Service | Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	$ 1	$ 9
[1] Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions.

Revenue - Schedule of Component

Revenue - Schedule of Components of Interest and Other Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Book-of-business settlements		$ 2	$ 7
Interest income		43	32
Other income		1	2
Total interest and other income		46	41
HWC [Member]
Disaggregation of Revenue [Line Items]
Book-of-business settlements		0	0
Interest income		9	5
Other income		0	1
Total interest and other income		9	6
R&B [Member]
Disaggregation of Revenue [Line Items]
Book-of-business settlements		2	7
Interest income		28	12
Other income		1	0
Total interest and other income		31	19
Corporate Segment [Member]
Disaggregation of Revenue [Line Items]
Book-of-business settlements		0	0
Interest income		6	15
Other income		0	1
Total interest and other income	[1]	$ 6	$ 16
[1] Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions.

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Disaggregation Of Revenue [Line Items]
Contract with Customer, Performance Obligation Satisfied in Previous Period	$ 9
Dec 31, 2023 [Member]
Disaggregation Of Revenue [Line Items]
Contract with Customer, Liability, Revenue Recognized	$ 295

Revenue - Schedule of Revenue b

Revenue - Schedule of Revenue by Geography (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 2,295	$ 2,203
Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		2,275	2,175
Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		2,275	2,175
HWC [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,344	1,296
HWC [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,327	1,281
HWC [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,327	1,281
R&B [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		950	888
R&B [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		947	885
R&B [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		947	885
Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	1	19
Corporate Segment [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	1	9
North America [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,146	1,115
North America [Member] | HWC [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		840	823
North America [Member] | R&B [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		306	291
North America [Member] | Corporate Segment [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	1
Europe [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		884	824
Europe [Member] | HWC [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		372	346
Europe [Member] | R&B [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		511	471
Europe [Member] | Corporate Segment [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1	7
International [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		245	236
International [Member] | HWC [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		115	112
International [Member] | R&B [Member] | Operating Segments [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		130	123
International [Member] | Corporate Segment [Member] | Service
Disaggregation Of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 0	$ 1
[1] Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions.

Revenue - Schedule of Contract

Revenue - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Billed Receivable, Current	$ 1,511	$ 1,581
Unbilled Receivable, Current	537	491
Contract asset, Current	382	500
Accounts receivable, net	2,430	2,572
Non-current accounts receivable, net	19	19
Contract asset, Noncurrent	925	909
Deferred revenue	$ 757	$ 677

Revenue - Schedule of Contrac_2

Revenue - Schedule of Contract Balances (Parenthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Allowance for doubtful debts	$ 39	$ 34

Revenue - Schedule of Remaining

Revenue - Schedule of Remaining Performance Obligations (Details) $ in Millions	Mar. 31, 2024 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 1,310
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-04-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 403
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 396
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 511
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Revenue - Schedule of Remaini_2

Revenue - Schedule of Remaining Performance Obligations (Details1) $ in Millions	Mar. 31, 2024 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 1,310

Segment Information - Narrative

Segment Information - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Information - Revenue (

Segment Information - Revenue (Net of Reimbursable Expenses) of the Reported Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 2,341	$ 2,244
Income from operations	280	285
HWC [Member]
Segment Reporting Information [Line Items]
Revenues	1,353	1,302
R&B [Member]
Segment Reporting Information [Line Items]
Revenues	981	907
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	2,314	2,191
Income from operations	539	489
Operating Segments [Member] | HWC [Member]
Segment Reporting Information [Line Items]
Revenues	1,336	1,287
Income from operations	336	309
Operating Segments [Member] | R&B [Member]
Segment Reporting Information [Line Items]
Revenues	978	904
Income from operations	$ 203	$ 180

Segment Information - Reconcili

Segment Information - Reconciliation of Information Reported by Segment to Condensed Consolidated Statement of Comprehensive Income Amounts (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Revenue:
Revenue		$ 2,341	$ 2,244
Amortization		(60)	(71)
Restructuring costs		(18)	(3)
Income from operations		280	285
Interest expense		(64)	(54)
Other income, net		26	25
INCOME FROM OPERATIONS BEFORE INCOME TAXES		242	256
Operating Segments [Member]
Revenue:
Revenue		2,314	2,191
Income from operations		539	489
Segment Reconciling Items [Member]
Revenue:
Revenue		27	53
Amortization		(60)	(71)
Restructuring costs	[1]	(18)	(3)
Transaction and transformation	[2]	(125)	(59)
Unallocated, net	[3]	(56)	(71)
Income from operations		280	285
Interest expense		(64)	(54)
Other income, net		$ 26	$ 25
[1] See Note 6 — Restructuring Costs for the composition of costs for 2024 and 2023. In 2024 and 2023, in addition to legal fees and other transaction costs, includes primarily consulting fees related to the Transformation program (see Note 6 — Restructuring Costs). Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.

Restructuring Costs - Narrative

Restructuring Costs - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Transaction and transformation	$ 125	$ 59
Transformation Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, description	In the fourth quarter of 2021, the Company initiated a three-year ‘Transformation program’ designed to enhance operations, optimize technology and align its real estate footprint to its new ways of working
Restructuring, Expected future effects			$ 1,125
Transaction and transformation	$ 119	$ 45
Transformation Program [Member] | Projected Annual Cost Savings by End of 2024 [Member]
Restructuring Cost and Reserve [Line Items]
Annual cost savings of program			425
Transformation Program [Member] | Cumulative Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Expected future effects			995
Transformation Program [Member] | Capital Expenditures [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Expected future effects			$ 130

Restructuring Costs - Summary o

Restructuring Costs - Summary of Total Restructuring Costs (Details) - Transformation Program [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended			39 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2024
Restructuring Cost and Reserve [Line Items]
Total					$ 211
Real Estate Rationalization [Member]
Restructuring Cost and Reserve [Line Items]
Total	$ 18	$ 46	$ 79	$ 19	162
Technology Modernization [Member]
Restructuring Cost and Reserve [Line Items]
Total	0	22	19	5	46
Process Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Total			1		1
Other [Member]
Restructuring Cost and Reserve [Line Items]
Total				2	2
Corporate, Non-Segment
Restructuring Cost and Reserve [Line Items]
Total					195
Corporate, Non-Segment | Real Estate Rationalization [Member]
Restructuring Cost and Reserve [Line Items]
Total	18	46	79	19	162
Corporate, Non-Segment | Technology Modernization [Member]
Restructuring Cost and Reserve [Line Items]
Total	0	15	16		31
Corporate, Non-Segment | Other [Member]
Restructuring Cost and Reserve [Line Items]
Total				2	2
HWC [Member]
Restructuring Cost and Reserve [Line Items]
Total					3
HWC [Member] | Technology Modernization [Member]
Restructuring Cost and Reserve [Line Items]
Total	0	2			2
HWC [Member] | Process Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Total			1		1
R&B [Member]
Restructuring Cost and Reserve [Line Items]
Total					13
R&B [Member] | Technology Modernization [Member]
Restructuring Cost and Reserve [Line Items]
Total	$ 0	$ 5	$ 3	$ 5	$ 13

Restructuring Costs - Rollforwa

Restructuring Costs - Rollforward of Liability Associated with Cash-based Charges (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Charges incurred	$ 18	$ 3
Transformation Program [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	11	6	$ 0	$ 6	$ 1
Charges incurred	7		2	30	28
Cash payments	(8)		(1)	(25)	(23)
Ending Balance	10		1	11	6
Transformation Program [Member] | Real Estate Rationalization [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	3	$ 6		6
Charges incurred	7			22	27
Cash payments	(8)			(25)	(21)
Ending Balance	2			3	6
Transformation Program [Member] | Technology Modernization [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	8
Charges incurred				8
Ending Balance	8			$ 8
Transformation Program [Member] | Process Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Charges incurred					1
Cash payments					(1)
Transformation Program [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance			0		1
Charges incurred			2
Cash payments			(1)		$ (1)
Ending Balance	$ 0		$ 1

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Loss Carryforwards [Line Items]
Provision for income taxes	$ 48	$ 50
Effective tax rate	19.90%	19.50%
Liabilities for uncertain tax positions	$ 52
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Expected decrease in liability for uncertain tax position	1
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Expected decrease in liability for uncertain tax position	$ 2

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Components of Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	$ 10,687
Accumulated impairment losses, beginning balance	(492)
Goodwill, net, beginning balance	10,195
Goodwill acquired	18
Foreign exchange	(27)
Goodwill, gross, ending balance	10,678
Accumulated impairment losses, ending balance	(492)
Goodwill, net, ending balance	10,186
HWC [Member]
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	7,866
Accumulated impairment losses, beginning balance	(130)
Goodwill, net, beginning balance	7,736
Goodwill acquired	18
Foreign exchange	(8)
Goodwill, gross, ending balance	7,876
Accumulated impairment losses, ending balance	(130)
Goodwill, net, ending balance	7,746
R&B [Member]
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	2,821
Accumulated impairment losses, beginning balance	(362)
Goodwill, net, beginning balance	2,459
Goodwill acquired	0
Foreign exchange	(19)
Goodwill, gross, ending balance	2,802
Accumulated impairment losses, ending balance	(362)
Goodwill, net, ending balance	$ 2,440

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Changes in the Net Carrying Amount of the Components of Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, gross carrying amount	$ 5,632		$ 5,638
Finite-lived intangible assets, accumulated amortization	(3,672)		(3,622)
Finite-lived intangible assets, net amount	1,960		2,016
Intangible assets acquired	10
Amortization	(60)	$ (71)
Foreign exchange	(6)
Client relationships [Member]
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, gross carrying amount	3,797		3,807
Finite-lived intangible assets, accumulated amortization	(2,548)		(2,514)
Finite-lived intangible assets, net amount	1,249		1,293
Intangible assets acquired	10
Amortization	(48)
Foreign exchange	(6)
Software [Member]
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, gross carrying amount	734		729
Finite-lived intangible assets, accumulated amortization	(731)		(726)
Finite-lived intangible assets, net amount	3		3
Intangible assets acquired	0
Amortization	0
Foreign exchange	0
Trademark and trade name [Member]
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, gross carrying amount	1,038		1,039
Finite-lived intangible assets, accumulated amortization	(352)		(342)
Finite-lived intangible assets, net amount	686		697
Intangible assets acquired	0
Amortization	(11)
Foreign exchange	0
Other [Member]
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, gross carrying amount	63		63
Finite-lived intangible assets, accumulated amortization	(41)		(40)
Finite-lived intangible assets, net amount	22		$ 23
Intangible assets acquired	0
Amortization	(1)
Foreign exchange	$ 0

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Narrative (Details)	Mar. 31, 2024
Finite-lived Intangible Assets [Roll Forward]
Weighted average remaining life of amortizable intangible assets	11 years 6 months

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Schedule of Future Estimated Amortization Expense for Amortizable Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Remainder of 2024	$ 172
2025	212
2026	203
2027	199
2028	194
Thereafter	980
Total	$ 1,960	$ 2,016

Derivative Financial Instrume_3

Derivative Financial Instruments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Gains on derivatives to be reclassified within the next twelve months	$ 1
Maximum [Member]
Derivative [Line Items]
Longest outstanding maturity	1 year 8 months 12 days
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 1,200	$ 1,200
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Derivative asset, fair value	$ 3	$ 3
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 118	$ 119
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Derivative asset, fair value	$ 2	$ 2

Derivative Financial Instrume_4

Derivative Financial Instruments - Schedule of Derivative Instruments Designated As Hedging Instrument Effect on Condensed Consolidated Statements of Comprehensive Income (Details) - Cash Flow Hedging [Member] - Designated as Hedging Instrument [Member] - Foreign exchange contracts [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Gain recognized in OCI (effective element)	$ 0	$ 1
(Loss)/gain reclassified from Accumulated OCL into income (effective element)	$ 0	$ (1)
Revenue [Member]
Derivative [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenues	Revenues
(Loss)/gain reclassified from Accumulated OCL into income (effective element)	$ (1)	$ 0
Salaries and Benefits [Member]
Derivative [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Labor and Related Expense	Labor and Related Expense
(Loss)/gain reclassified from Accumulated OCL into income (effective element)	$ 1	$ (1)

Derivative Financial Instrume_5

Derivative Financial Instruments - Schedule of Derivative Instruments, Effect on Condensed Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other income, net [Member] | Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Derivative [Line Items]
Gain recognized in income	$ 1	$ 8

Debt - Schedule of Current and

Debt - Schedule of Current and Long-term Debt (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Current debt	$ 650,000,000	$ 650,000,000
Long-term debt, excluding current maturities	5,307,000,000	4,567,000,000
Revolving 1.5 Billion Dollar Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	1,500,000,000
3.600% senior notes due 2024 [Member]
Debt Instrument [Line Items]
Current debt	$ 650,000,000	$ 650,000,000
Stated interest rate	3.60%	3.60%
Debt instrument maturity year	2024	2024
4.400% senior notes due 2026 [Member]
Debt Instrument [Line Items]
Stated interest rate	4.40%	4.40%
Debt instrument maturity year	2026	2026
Long-term debt, excluding current maturities	$ 548,000,000	$ 548,000,000
4.650% senior notes due 2027 [ Member]
Debt Instrument [Line Items]
Stated interest rate	4.65%	4.65%
Debt instrument maturity year	2027	2027
Long-term debt, excluding current maturities	$ 745,000,000	$ 745,000,000
4.500% senior notes due 2028 [Member]
Debt Instrument [Line Items]
Stated interest rate	4.50%	4.50%
Debt instrument maturity year	2028	2028
Long-term debt, excluding current maturities	$ 598,000,000	$ 598,000,000
2.950% senior notes due 2029 [Member]
Debt Instrument [Line Items]
Stated interest rate	2.95%	2.95%
Debt instrument maturity year	2029	2029
Long-term debt, excluding current maturities	$ 727,000,000	$ 726,000,000
5.350% senior notes due 2033 [Member]
Debt Instrument [Line Items]
Stated interest rate	5.35%	5.35%
Debt instrument maturity year	2033	2033
Long-term debt, excluding current maturities	$ 741,000,000	$ 741,000,000
6.125% senior notes due 2043 [Member]
Debt Instrument [Line Items]
Stated interest rate	6.125%	6.125%
Debt instrument maturity year	2043	2043
Long-term debt, excluding current maturities	$ 272,000,000	$ 272,000,000
5.050% senior notes due 2048 [Member]
Debt Instrument [Line Items]
Stated interest rate	5.05%	5.05%
Debt instrument maturity year	2048	2048
Long-term debt, excluding current maturities	$ 395,000,000	$ 395,000,000
3.875% senior notes due 2049 [Member]
Debt Instrument [Line Items]
Stated interest rate	3.875%	3.875%
Debt instrument maturity year	2049	2049
Long-term debt, excluding current maturities	$ 542,000,000	$ 542,000,000
5.900% senior notes due 2054 [Member]
Debt Instrument [Line Items]
Stated interest rate	5.90%	5.90%
Debt instrument maturity year	2054	2054
Long-term debt, excluding current maturities	$ 739,000,000	$ 0

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($) $ in Millions		6 Months Ended
	Mar. 05, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
5.900% senior notes due 2054 [Member]
Debt Instrument [Line Items]
Stated interest rate			5.90%	5.90%
3.600% senior notes due 2024 [Member]
Debt Instrument [Line Items]
Stated interest rate			3.60%	3.60%
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from debt, net of issuance costs	$ 739
Senior Notes [Member] | 5.900% senior notes due 2054 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 750
Stated interest rate	5.90%
Effective interest rate (as a percent)	6%
Maturity date	Mar. 05, 2054
Senior Notes [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Stated interest rate		3.60%
Repayment of debt		$ 650

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Millions		Mar. 31, 2024 USD ($)		Dec. 31, 2023 USD ($)
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		0.13		0.1328
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member] | Minimum [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		0.11
Contingent consideration [Member] | Fair Value Inputs, Discount Rate [Member] | Maximum [Member]
Liabilities:
Fair value inputs, weighted-average discount rate		0.138
Recurring [Member]
Assets:
Mutual funds / exchange traded funds	[1]	$ 105		$ 102
Derivative financial instruments	[2]	5		6
Liabilities:
Contingent consideration	[4]	34	[3]	31
Derivative financial instruments	[2]	0		1
Recurring [Member] | Commingled Funds [Member]
Assets:
Deferred compensation plans	[1],[5]	10		9
Recurring [Member] | Hedge Funds [Member]
Assets:
Deferred compensation plans	[1],[6]	8		8
Recurring [Member] | Fiduciary Assets [Member]
Assets:
Mutual funds / exchange traded funds		265		215
Recurring [Member] | Level 1 [Member]
Assets:
Mutual funds / exchange traded funds	[1]	105		102
Derivative financial instruments	[2]	0		0
Liabilities:
Contingent consideration	[4]	0	[3]	0
Derivative financial instruments	[2]	0		0
Recurring [Member] | Level 1 [Member] | Commingled Funds [Member]
Assets:
Deferred compensation plans	[1],[5]	0		0
Recurring [Member] | Level 1 [Member] | Hedge Funds [Member]
Assets:
Deferred compensation plans	[1],[6]	0		0
Recurring [Member] | Level 1 [Member] | Fiduciary Assets [Member]
Assets:
Mutual funds / exchange traded funds		265		215
Recurring [Member] | Level 2 [Member]
Assets:
Mutual funds / exchange traded funds	[1]	0		0
Derivative financial instruments	[2]	5		6
Liabilities:
Contingent consideration	[4]	0	[3]	0
Derivative financial instruments	[2]	0		1
Recurring [Member] | Level 2 [Member] | Commingled Funds [Member]
Assets:
Deferred compensation plans	[1],[5]	0		0
Recurring [Member] | Level 2 [Member] | Hedge Funds [Member]
Assets:
Deferred compensation plans	[1],[6]	0		0
Recurring [Member] | Level 2 [Member] | Fiduciary Assets [Member]
Assets:
Mutual funds / exchange traded funds		0		0
Recurring [Member] | Level 3 [Member]
Assets:
Mutual funds / exchange traded funds	[1]	0		0
Derivative financial instruments	[2]	0		0
Liabilities:
Contingent consideration	[4]	34	[3]	31
Derivative financial instruments	[2]	0		0
Recurring [Member] | Level 3 [Member] | Commingled Funds [Member]
Assets:
Deferred compensation plans	[1],[5]	0		0
Recurring [Member] | Level 3 [Member] | Hedge Funds [Member]
Assets:
Deferred compensation plans	[1],[6]	0		0
Recurring [Member] | Level 3 [Member] | Fiduciary Assets [Member]
Assets:
Mutual funds / exchange traded funds		$ 0		$ 0
[1] With the exception of the funds included in fiduciary assets, the majority of these balances are held as part of deferred compensation plans with related liabilities in other current liabilities and other non-current liabilities on the condensed consolidated balance sheets. See Note 9 — Derivative Financial Instruments for further information on our derivative investments. Consideration due to be paid across multiple years until 2029. Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The fair value weighted-average discount rates used in our material contingent consideration calculations were 13.00 % and 13.28 % at March 31, 2024 and December 31, 2023, respectively. The range of these discount rates was 11.00 % - 13.80 % at March 31, 2024. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable. Consists of the Towers Watson Global Equity Focus Fund, for which redemptions can occur on any business day, and require a minimum of one business day’s notice. Consists of the Towers Watson Alternative Credit Fund, for which the redemption period is generally quarterly, however requires a 50-day notice.

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Liabilities Measured Using Significant Unobservable Inputs Level 3 (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of beginning of period	$ 31
Obligations assumed	3
Payments	0
Realized and unrealized losses	$ 1	[1]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Cost and Expense, Operating
Foreign exchange	$ (1)
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Liability, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other Cost and Expense, Operating
Balance as of end of period	$ 34
[1] Realized and unrealized losses include accretion and adjustments to contingent consideration liabilities, which are included within Interest expense and Other operating expenses, respectively, on the condensed consolidated statements of comprehensive income.

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value Disclosures [Abstract]
Fair value significant transfers to or from Level 3	$ 0

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Assets and Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current debt	$ 650	$ 650
Long-term debt	5,307	4,567
Carrying Value [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term note receivable	73	74
Current debt	650	650
Long-term debt	5,307	4,567
Fair Value [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term note receivable	67	70
Current debt	648	645
Long-term debt	$ 5,066	$ 4,359

Retirement Benefits - Narrative

Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Compensation and Retirement Disclosure [Line Items]
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)	98%
Defined contribution plan, employer contribution	$ 43	$ 40
Pension Plan [Member] | United States [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions	0
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	0
Pension Plan [Member] | United Kingdom [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions	1
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	1
Pension Plan [Member] | Other Foreign Plans [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions	9
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	$ 6

Retirement Benefits - Net Perio

Retirement Benefits - Net Periodic Benefit Cost (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 14
Interest cost	49	49
Expected return on plan assets	(76)	(76)
Amortization of net loss	9	3
Amortization of prior service credit	0	0
Net periodic benefit (income)/cost	(7)	(10)
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	28	29
Expected return on plan assets	(39)	(39)
Amortization of net loss	14	12
Amortization of prior service credit	(3)	(3)
Net periodic benefit (income)/cost	1	0
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	3
Interest cost	7	7
Expected return on plan assets	(10)	(9)
Amortization of net loss	0	0
Amortization of prior service credit	0	0
Net periodic benefit (income)/cost	$ 1	$ 1

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Costs Recorded in Condensed Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Finance lease cost:
Amortization of right-of-use assets	$ 1	$ 0
Interest on lease liabilities	0	1
Operating lease cost	42	34
Variable lease cost	14	12
Sublease income	(5)	(3)
Total lease cost, net	$ 52	$ 44

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lessee, Lease, Description [Line Items]
Lease cost	$ 52	$ 44
Restructuring Charges [Member]
Lessee, Lease, Description [Line Items]
Lease cost	$ 15	$ 1

Supplementary Information for_3

Supplementary Information for Certain Balance Sheet Accounts - Deferred Revenue and Accrued Expenses (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable, accrued liabilities and deferred revenue	$ 1,106	$ 1,073
Accrued discretionary and incentive compensation	266	795
Accrued vacation	183	150
Other employee-related liabilities	83	86
Total deferred revenue and accrued expenses	$ 1,638	$ 2,104

Supplementary Information for_4

Supplementary Information for Certain Balance Sheet Accounts - Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Dividends payable	$ 108	$ 103
Income taxes payable	56	50
Interest payable	45	50
Deferred compensation plan liabilities	12	16
Contingent and deferred consideration on acquisitions	24	7
Accrued retirement benefits	31	31
Payroll and other benefits-related liabilities	267	166
Other taxes payable	63	78
Third-party commissions	108	106
Other current liabilities	53	71
Total other current liabilities	$ 767	$ 678

Supplementary Information for_5

Supplementary Information for Certain Balance Sheet Accounts - Provision For Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Claims, lawsuits and other proceedings	$ 313	$ 306
Other provisions	64	59
Total provision for liabilities	$ 377	$ 365

Other Income, Net (Details)

Other Income, Net (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Other Income and Expenses [Abstract]
Net periodic pension and postretirement benefit credits		$ 22	$ 28
Interest in earnings of associates and other investments		0	1
Foreign exchange gain/(loss)	[1]	3	(5)
Other		1	1
Other income, net		$ 26	$ 25
[1] Includes the offsetting effects of the Company's foreign currency hedging program. See Note 9 — Derivative Financial Instruments.

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		$ 9,520
Stockholders' equity attributable to parent, ending balance		9,489
Foreign currency translation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance	[1]	(816)	$ (987)
Other comprehensive (loss)/income before reclassifications	[1]	(63)	43
Loss reclassified from accumulated other comprehensive loss (net of income tax)	[1]	0	0
Net current-period other comprehensive (loss)/income	[1]	(63)	43
Stockholders' equity attributable to parent, ending balance	[1]	(879)	(944)
Derivative instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance	[1]	11	9
Other comprehensive (loss)/income before reclassifications	[1]	0	2
Loss reclassified from accumulated other comprehensive loss (net of income tax)	[1]	0	0
Net current-period other comprehensive (loss)/income	[1]	0	2
Stockholders' equity attributable to parent, ending balance	[1]	11	11
Defined pension and post-retirement benefit costs [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		(2,051)	(1,643)
Other comprehensive (loss)/income before reclassifications		0	(1)
Loss reclassified from accumulated other comprehensive loss (net of income tax)		14	9
Net current-period other comprehensive (loss)/income		14	8
Stockholders' equity attributable to parent, ending balance		(2,037)	(1,635)
Total [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		(2,856)	(2,621)
Other comprehensive (loss)/income before reclassifications		(63)	44
Loss reclassified from accumulated other comprehensive loss (net of income tax)		14	9
Net current-period other comprehensive (loss)/income		(49)	53
Stockholders' equity attributable to parent, ending balance		$ (2,905)	$ (2,568)
[1] Reclassification adjustments from accumulated other comprehensive loss related to derivative instruments are included in Revenue and Salaries and benefits in the accompanying condensed consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the derivative settlements.

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from AOCI, Current Period, Tax	$ 5	$ 3

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share	0	0
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share	0	0
Time-based award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	0
Restricted share units outstanding	0.4	0.4
Performance-Based Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	0	0
Restricted share units outstanding	0.5	0.5

Earnings Per Share - Basic and

Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Income (Loss)	$ 190	$ 203
Basic average number of shares outstanding (shares)	103	107
Dilutive effect of potentially issuable shares (shares)	1	1
Diluted average number of shares outstanding (shares)	104	108
Basic earnings per share	$ 1.84	$ 1.89
Dilutive effect of potentially issuable shares (USD per share)	(0.01)	(0.01)
Diluted earnings per share	$ 1.83	$ 1.88

Supplemental Disclosures of C_3

Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Supplemental disclosures of cash flow information:
Cash and cash equivalents		$ 1,893	$ 1,135	$ 1,424
Fiduciary funds (included in fiduciary assets)		3,358	3,227
Total cash, cash equivalents and restricted cash		5,251	4,362
INCREASE/(DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	[1]	1,506	(380)
Non-Fiduciary [Member]
Supplemental disclosures of cash flow information:
INCREASE/(DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH		487	(130)
Fiduciary [Member]
Supplemental disclosures of cash flow information:
INCREASE/(DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH		$ 1,019	$ (250)
[1] The amounts of cash, cash equivalents and restricted cash, their respective classification on the condensed consolidated balance sheets as well as their respective portions of the increase or decrease in cash, cash equivalents and restricted cash for each of the periods presented have been included in Note 19 — Supplemental Disclosures of Cash Flow Information.