Basis of Presentation and Recent Accounting Pronouncements (Policies)	6 Months Ended
Jun. 30, 2026
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. Certain prior-period amounts have been reclassified to conform to the current-period presentation. 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 25, 2026, and may be accessed via EDGAR on the SEC’s web site at www.sec.gov. The results of operations for the three and six months ended June 30, 2026 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 November 2024, the FASB issued ASU No. 2024-03, Disaggregation of Income Statement Expense, which is intended to provide transparency about the components of expenses included in the income statement. This ASU requires public companies to disclose additional information about certain expenses in the notes to the financial statements on a quarterly and annual basis, including purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses. The ASU requires a new tabular disclosure format that centralizes expense information and additional qualitative disclosure. The guidance does not change the existing income statement presentation. The annual requirements for this ASU become effective with the Company's Annual Report on Form 10-K for the year ended December 31, 2027, and for its interim periods beginning on January 1, 2028. Early adoption is permitted. The guidance is to be applied prospectively, with the option for retrospective application. The Company currently does not plan to early-adopt this ASU and is assessing the expected impact on its condensed consolidated financial statements. In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software, which is intended to clarify and modernize the accounting for costs related to internal-use software. This ASU changes capitalization requirements from being tied to development stages and instead creates a capitalization threshold which is achieved when it is probable the software will be completed for its intended purpose. The annual and interim requirements for this ASU become effective for the Company on January 1, 2028. Early adoption is permitted and may be applied using a prospective, retrospective, or modified transition approach. The Company is assessing all aspects of the ASU, including adoption timing and transition method, and the expected impact on its condensed consolidated financial statements. Adopted In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which is intended to improve guidance on the measurement of credit losses for accounts receivable and contract assets. This ASU provides an optional practical expedient to assume that current conditions as of the balance sheet date do not change for the remaining life of the assets. The requirements for this ASU became effective for the Company on January 1, 2026, at which time it was adopted. This ASU did not have a material impact on our condensed consolidated financial statements.
Other Legislation	Other Legislation Pillar Two In December 2021, the Organisation for Economic Co-operation and Development (‘OECD’) and 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. In 2023, many E.U. countries, including Ireland, enacted the necessary legislation (based on the OECD Model Rules) to implement Pillar Two in 2024. Other countries and territories introduced Pillar Two legislation in 2024 and 2025. In January 2026, the OECD announced the release of a new package of administrative guidance under the Pillar Two global minimum tax rules (the ‘side-by-side’ (SbS) package). Key components of the package include a simplified effective tax rate safe harbor, an extension of the transitional country-by-country reporting safe harbor, a substance-based tax incentive safe harbor, a side-by-side safe harbor for certain multinational groups located in eligible jurisdictions, an ultimate parent entity safe harbor for eligible countries, and a commitment to focus on additional clarifications and simplifications. These new safe harbor rules do not affect the application of a qualified domestic minimum top-up tax. Except for the extension of the transitional country-by-country reporting safe harbor, the Company does not expect the new safe harbors to apply. The Pillar Two minimum tax is treated as a period-cost beginning in 2024 and does not have a material impact on the Company's financial results of operations for the periods presented. H.R. 1 On July 4, 2025, the ‘Act to provide for reconciliation pursuant to title II of H. Con. Res. 14’ (‘H.R. 1’) was enacted into law and generally became effective on January 1, 2026, with certain exceptions. H.R. 1 included numerous changes to existing tax law affecting businesses, including extending and modifying certain key provisions of the Tax Cuts and Jobs Act of 2017, both domestic and international, expanding certain Investment Retirement Account incentives while accelerating the phase-out of others. In 2025, the Company recognized cash tax benefits related to the acceleration of certain timing differences. The Company will continue to evaluate the overall impact of H.R. 1 and related regulations on our operations and tax positions.
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. • Debt securities are classified as Level 1 financial instruments as they are based on quoted market prices in active markets. • 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.

Basis of Presentation and Recent Accounting Pronouncements (Policies)

6 Months Ended

Jun. 30, 2026

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. Certain prior-period amounts have been reclassified to conform to the current-period presentation. 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 25, 2026, and may be accessed via EDGAR on the SEC’s web site at www.sec.gov.

The results of operations for the three and six months ended June 30, 2026 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 November 2024, the FASB issued ASU No. 2024-03, Disaggregation of Income Statement Expense, which is intended to provide transparency about the components of expenses included in the income statement. This ASU requires public companies to disclose additional information about certain expenses in the notes to the financial statements on a quarterly and annual basis, including

purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses. The ASU requires a new tabular disclosure format that centralizes expense information and additional qualitative disclosure. The guidance does not change the existing income statement presentation. The annual requirements for this ASU become effective with the Company's Annual Report on Form 10-K for the year ended December 31, 2027, and for its interim periods beginning on January 1, 2028. Early adoption is permitted. The guidance is to be applied prospectively, with the option for retrospective application. The Company currently does not plan to early-adopt this ASU and is assessing the expected impact on its condensed consolidated financial statements.

In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software, which is intended to clarify and modernize the accounting for costs related to internal-use software. This ASU changes capitalization requirements from being tied to development stages and instead creates a capitalization threshold which is achieved when it is probable the software will be completed for its intended purpose. The annual and interim requirements for this ASU become effective for the Company on January 1, 2028. Early adoption is permitted and may be applied using a prospective, retrospective, or modified transition approach. The Company is assessing all aspects of the ASU, including adoption timing and transition method, and the expected impact on its condensed consolidated financial statements.

Adopted

In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which is intended to improve guidance on the measurement of credit losses for accounts receivable and contract assets. This ASU provides an optional practical expedient to assume that current conditions as of the balance sheet date do not change for the remaining life of the assets. The requirements for this ASU became effective for the Company on January 1, 2026, at which time it was adopted. This ASU did not have a material impact on our condensed consolidated financial statements.

Other Legislation

Pillar Two

In December 2021, the Organisation for Economic Co-operation and Development (‘OECD’) and 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. In 2023, many E.U. countries, including Ireland, enacted the necessary legislation (based on the OECD Model Rules) to implement Pillar Two in 2024. Other countries and territories introduced Pillar Two legislation in 2024 and 2025. In January 2026, the OECD announced the release of a new package of administrative guidance under the Pillar Two global minimum tax rules (the ‘side-by-side’ (SbS) package). Key components of the package include a simplified effective tax rate safe harbor, an extension of the transitional country-by-country reporting safe harbor, a substance-based tax incentive safe harbor, a side-by-side safe harbor for certain multinational groups located in eligible jurisdictions, an ultimate parent entity safe harbor for eligible countries, and a commitment to focus on additional clarifications and simplifications. These new safe harbor rules do not affect the application of a qualified domestic minimum top-up tax. Except for the extension of the transitional country-by-country reporting safe harbor, the Company does not expect the new safe harbors to apply. The Pillar Two minimum tax is treated as a period-cost beginning in 2024 and does not have a material impact on the Company's financial results of operations for the periods presented.

H.R. 1

On July 4, 2025, the ‘Act to provide for reconciliation pursuant to title II of H. Con. Res. 14’ (‘H.R. 1’) was enacted into law and generally became effective on January 1, 2026, with certain exceptions. H.R. 1 included numerous changes to existing tax law affecting businesses, including extending and modifying certain key provisions of the Tax Cuts and Jobs Act of 2017, both domestic and international, expanding certain Investment Retirement Account incentives while accelerating the phase-out of others. In 2025, the Company recognized cash tax benefits related to the acceleration of certain timing differences. The Company will continue to evaluate the overall impact of H.R. 1 and related regulations on our operations and tax positions.

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.

•

Debt securities are classified as Level 1 financial instruments as they are based on quoted market prices in active markets.

•

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.