Goodwill [Line Items] Goodwill [Line Items] Document Transition Report Document Transition Report Revenue, Remaining Performance Obligation Revenue, Remaining Performance Obligation, Amount Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Money Market Funds [Member] Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Liability, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Process Optimization Member Process Optimization Member Process optimization [Member] Schedule of Derivative Instruments Designated/Nondesignated As Hedging Instrument Effect on Condensed Consolidated Statements of Comprehensive Income Derivative Instruments, Gain (Loss) [Table Text Block] Depreciation Depreciation Not Including Integration Component Depreciation, not including integration component. Effect on Future Earnings, Amount Annual cost savings of program Income/(loss) from discontinued operations per share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Restructuring Cost and Reserve [Line Items] Geographical Geographical [Axis] Schedule of Change in Fair Value of Level 3 Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Non-controlling interests [Member] Noncontrolling Interest [Member] Open-end mutual funds member Open-End Mutual Funds [Member] Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest INCOME FROM CONTINUING OPERATIONS Income from continuing operations Other non-current liabilities Other Liabilities, Noncurrent Total other non-current liabilities Schedule Of Segment Reporting Information By Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Restricted share units [Member] Restricted Stock Units (RSUs) [Member] 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Two Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Gain/(loss) on disposal of operations Pooled / commingled funds [Member] Commingled Funds [Member] Commingled funds. Schedule of Prepaid and Other Current Assets Schedule of Other Current Assets [Table Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Revenue from Contract with Customer, Excluding Assessed Tax, Total Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Third-party commissions Accrued Sales Commission, Current Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Debt instrument maturity year Debt Instrument Maturity Year Debt instrument maturity year. 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Europe [Member] Europe [Member] Net Income (Loss) Attributable to Noncontrolling Interest, Total Income attributable to non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Assets: Assets, Fair Value Disclosure [Abstract] Finance leases Finance Lease, Liability, Noncurrent Schedule Of Goodwill [Table] Schedule of Goodwill [Table] Balance Sheet Location [Axis] Total current assets Assets, Current Restricted Cash and Cash Equivalents [Axis] BDA [Member] Benefits Delivery And Administration [Member] Benefits delivery and administration. TOTAL LIABILITIES AND EQUITY Liabilities and Equity Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Goodwill disposals Goodwill, Written off Related to Sale of Business Unit Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance Stock options outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive income/(loss) attributable to WTW Accounts receivable, net balances excluded from held-for-sale Accounts Receivable Net Balances Excluded From Held For Sale Accounts receivable, net balances excluded from held-for-sale. Trading Symbol Trading Symbol Settled Litigation [Member] Settled Litigation [Member] Common Stock, Shares, Issued, Total Ordinary shares, shares issued Common Stock, Shares, Issued Total prepaid and other current assets Prepaid and other current assets Prepaid Expense and Other Assets, Current Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Merger-Related Securities Litigation [Member] Willis Towers Watson Merger Related Securities Litigation [Member] Willis Towers Watson merger-related securities litigation. AOCL [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] Debt Instrument [Table] Schedule of Long-Term Debt Instruments [Table] Equity, beginning balance (in shares) Equity, ending balance (in shares) Shares, Outstanding Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations, Beginning Balance Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations, Ending Balance Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations Cash and cash equivalents and fiduciary funds (included in current assets held for sale) Total [Member] AOCI Attributable to Parent [Member] Long-term Debt, Current Maturities, Total Current debt Long-Term Debt, Current Maturities AOCI Attributable to Parent, Net of Tax [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Line Items] Entity Address, City or Town Entity Address, City or Town Senior Notes Due 203305350[Member] Senior Notes Due 203305350[Member] 5.350% senior notes due 2033 [Member] Cash Flow, Supplemental Disclosures [Text Block] Supplemental Disclosures of Cash Flow Information Debt Debt Disclosure [Text Block] Disposal Group Name Disposal Group Name [Axis] Dividends paid Payments of Ordinary Dividends, Common Stock Real estate rationalization. Real estate rationalization [Member] Real Estate Rationalization [Member] Subsequent Event [Member] Subsequent Event [Member] Subsequent Event Type [Axis] Willis Towers Watson Public Limited Company [Member] Willis Towers Watson Public Limited Company [Member] Willis Towers Watson public limited company. (Loss)/gain recognized in income Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net, Total Loss recognized in income Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Restructuring and Related Activities, Description Restructuring, description Fiduciary liabilities Fiduciary Liabilities Current Fiduciary liabilities, current. Non-cash restructuring charges Restructuring Reserve, Settled without Cash Counterparty Name Counterparty Name [Axis] Preference shares, nominal value (USD per share) Preferred Stock, Par or Stated Value Per Share 3.600% senior notes due 2024 [Member] Senior Notes Due202403600 [Member] Senior notes due 2024, 03600. Statement of Stockholders' Equity [Abstract] Book-of-Business Settlements Book-of-Business Settlements. Current lease liabilities Operating Lease, Liability, Current Debt Instrument, Maturity Date Maturity Date Payroll and other benefits-related liabilities Payroll and other benefits-related liabilities Payroll and other benefits-related liabilities. 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Supplemental Cash Flow Information [Abstract] Supplemental disclosures of cash flow information: Retained earnings [Member] Retained Earnings [Member] Class of Stock Class of Stock [Axis] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance Restricted share units outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Total equity Equity, beginning balance Equity, ending balance Equity, Including Portion Attributable to Noncontrolling Interest Gain on disposal Gain (Loss) on Disposition of Assets Gain (Loss) on Disposition of Assets, Total Deferred Income Tax Liabilities, Net, Total Deferred tax liabilities Deferred Income Tax Liabilities, Net Western Europe [Member] Western Europe [Member] Western Europe. Minimum [Member] Minimum [Member] Minimum [Member] Expected decrease in liability for uncertain tax position Decrease in Unrecognized Tax Benefits is Reasonably Possible Total revenue Revenue Revenues Segment revenue Total WTW shareholders' equity [Member] Parent [Member] Derivative Instruments and Hedging Activities Disclosure [Abstract] Forecast [Member] Liabilities: Liabilities, Fair Value Disclosure [Abstract] Equity Component Equity Component [Domain] Segments Segments [Axis] Less: income attributable to non-controllable interests Income (Loss) from Continuing Operations, Net of Tax, Attributable to Noncontrolling Interest Less: income attributable to non-controllable interests Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Derivatives Derivative Liability, Current Total costs of providing services Disposal Group Including Discontinued Operation Costs Of Providing Services Disposal group including discontinued operation costs of providing services. Defined benefit pension plans, employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Adjustments to reconcile net income to total net cash from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Measurement Frequency Measurement Frequency [Axis] Sublease income Sublease Income Foreign exchange Goodwill, Foreign Currency Translation Gain (Loss) Debt Disclosure [Abstract] Tax exempt gain on sale Preliminary pre-tax gain on sale Adjustment to gain on disposal of Willis Re Net (gain)/loss on disposal of operations Gains on derivatives to be reclassified within the next twelve months Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred Gains/losses on derivatives to be reclassified within the next twelve months Entity Current Reporting Status Entity Current Reporting Status Ordinary shares, shares authorized Common Stock, Shares Authorized Revenue: Segment Reconciliation [Abstract] Income/(loss) from discontinued operations per share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Acquisitions and Divestitures Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Tax Legislation Other Legislation [Policy Text Block] Other legislation Rollforward of liability associated with cash-based charges. Rollforward of liability associated with cash-based charges [Table Text Block] Rollforward of Liability Associated with Cash-based Charges ASSETS Assets [Abstract] Proceeds from issuance of shares Proceeds from Issuance of Common Stock Hedging Relationship Hedging Relationship [Axis] Amortization of Intangible Assets, Total Amortization Amortization Amortization Amortization of Intangible Assets Stock Repurchased and Retired During Period, Value Shares repurchased Schedule of Liabilities Whose Carrying Values Differ from the Fair Value and are Not Measured on a Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Repayments of Long-term Debt, Total Repayments of debt Repayments of Long-Term Debt Income (Loss) from Continuing Operations, Per Diluted Share Income from continuing operations per share Diluted earnings per share from continuing operations attributable to WTW Diluted earnings per share from continuing operations attributable to WTW Discontinued Operation, Tax Effect of Discontinued Operation, Total Discontinued Operation, Tax Effect of Discontinued Operation Provision for income taxes Provision for income taxes Foreign exchange (loss)/gain Realized Gain (Loss), Foreign Currency Transaction, before Tax Other Noncash Income (Expense), Total Other, net Other Noncash Income (Expense) Deconsolidation gain or loss amount Deconsolidation, Gain (Loss), Amount Restructuring Reserve, Total Restructuring Reserve Beginning Balance Ending Balance Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability, Revenue Recognized Willis Re [Member] Willis Re. Willis Re SAPA [Member] Current Fiscal Year End Date Current Fiscal Year End Date Share-based Payment Arrangement, Noncash Expense, Total Share-based compensation Share-Based Payment Arrangement, Noncash Expense Income from operations Operating Income (Loss) Segment operating income Income/(loss) from operations Repayments of Debt Repayment of debt Dilutive effect of potentially issuable shares, continuing operations (USD per share) Dilutive Securities Effect On Basic Earnings Per Share Continuing Operations Dilutive securities effect on basic earnings per share continuing operations. Dilutive effect of potentially issuable shares Income Tax Expense (Benefit), Total Provision for income taxes Provision for income taxes Income Tax Expense (Benefit) Liability, Defined Benefit Plan, Noncurrent, Total Liability for pension benefits Liability, Defined Benefit Plan, Noncurrent Revenue, Percentage of Total Revenue Individual Revenue Streams Percentage Of Total Revenue Individual revenue streams percentage of total revenue. Nature of Operations Nature of Operations [Text Block] Deferred compensation plan assets current. Deferred Compensation Plan Assets Current Deferred compensation plan assets Payments of deferred and contingent consideration related to acquisitions Payment for Contingent Consideration Liability, Financing Activities Payments for Restructuring Cash payments Cash payments Contract with Customer, Performance Obligation Satisfied in Previous Period Contract with Customer, Performance Obligation Satisfied in Previous Period Minority Interest [Line Items] Noncontrolling Interest [Line Items] Payment, Tax Withholding, Share-Based Payment Arrangement Cash paid for employee taxes on withholding shares Cash paid for employee taxes on withholding shares Disaggregation Of Revenue [Table] Disaggregation of Revenue [Table] Measurement Input Type Measurement Input Type [Domain] Schedule of Selected Financial Information and Summary of Total Assets and Liabilities Relates to the Operations of Willis Re Disposal Groups, Including Discontinued Operations [Table Text Block] Income taxes payable Taxes Payable, Current Taxes Payable, Current, Total Finite-Lived Intangible Assets, Net, Ending Balance Finite-Lived Intangible Assets, Net, Beginning Balance Total Finite-lived intangible assets, net amount Finite-Lived Intangible Assets, Net Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Finite-lived Intangible Assets [Roll Forward] Finite-Lived Intangible Assets [Roll Forward] Revenue Revenue from Contract with Customer [Text Block] Revenue [Member] Revenue [Member] Revenue member. Disposal Group Name Disposal Group Name [Domain] Effect of exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Debt Instrument, Face Amount Debt instrument, face amount Hedging Relationship Hedging Relationship [Domain] Business combination contingent consideration liability and deferred consideration current. Business Combination Contingent Consideration Liability And Deferred Consideration Current Contingent and deferred consideration on acquisitions Measurement Basis Measurement Basis [Axis] Other income, net Other income, net Other Nonoperating Income (Expense) 4.650% senior notes due 2027 [ Member] Senior Notes Due 202704650 [Member] Senior notes due 202704650 [Member]. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Realized and unrealized losses Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest, Total Comprehensive income attributable to non-controlling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Long-Term Debt, Type [Domain] Commitments and Contingencies Disclosure [Abstract] Other Assets, Noncurrent, Total Other non-current assets Other Assets, Noncurrent Broking [Member] Broking [Member] Broking. Earnout receivable in cash in 2025 Earnout Receivable In Cash Earnout receivable in cash not recognized as an asset on balance sheet. Disposal Group, Including Discontinued Operation, Revenue Revenue from discontinued operations Aon Plc [Member] Aon Plc [Member] Aon plc. 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Dilutive effect of potentially issuable shares Dilutive effect of potentially issuable shares Basic earnings per share Earnings Per Share, Basic Basic earnings per share Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Non-Fiduciary. Non-Fiduciary [Member] Business Combinations [Abstract] Income Statement [Abstract] Amortization of net loss Defined Benefit Plan, Amortization of Gain (Loss) Amortization of net loss Related Party, Type [Axis] Other provisions Other Accrued Liabilities, Noncurrent Performance-Based Stock Units [Member] Performance Shares [Member] 4.400% senior notes due 2026 [Member] Senior Notes Due202604400 [Member] Senior notes due 2026, 04400. 4.625% senior notes due 2023 [Member] Senior Notes Due202304625 [Member] Senior notes due 2023, 04625. 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Transaction and transformation, net Finite-Lived Intangible Assets Acquired Intangible assets acquired Proceeds from issuance of debt Proceeds from Issuance of Debt Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income from continuing operations attributable to WTW Income from continuing operations attributable to WTW Other Foreign Plans [Member] Other Foreign Plans [Member] Other foreign plans. Document Period End Date Document Period End Date Statistical Measurement Statistical Measurement [Axis] Accounts Receivable, Allowance for Credit Loss, Ending Balance Accounts Receivable, Allowance for Credit Loss, Beginning Balance Allowance for doubtful debts Accounts Receivable, Allowance for Credit Loss Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Cash and fiduciary funds transferred in sale of operations Cash Divested from Deconsolidation Cash outflow of cash and fiduciary cash related to settlement. Cash outflow of cash and non-fiduciary cash related to settlement. Reimbursable expenses and other Reimbursable Expenses And Other Reimbursable expenses and other. Diluted earnings per share Diluted earnings per share Earnings Per Share, Diluted Proposed Combination with AON Plc [Member] Proposed Combination With A O N Plc [Member] Proposed combination with AON plc. Fiduciary assets Funds Held for Clients Product and Service Product and Service [Domain] Finance lease cost: Lease, Cost [Abstract] Revenue from Contract with Customer [Abstract] Debt Instrument, Name Debt Instrument, Name [Domain] Other Restructuring [Member] Other [Member] Cumulative costs. 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Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Proceeds from (Payments to) Noncontrolling Interests, Total Acquisitions of and dividends paid to non-controlling interests Proceeds from (Payments to) Noncontrolling Interests Earnings Per Share, Basic [Abstract] Basic earnings per share: Other income, net Disposal Group Including Discontinued Operation Other Expense Income Net Disposal group including discontinued operation other expense (income) net. Equity Components Equity Components [Axis] Deferred compensation plan liabilities Deferred Compensation Liability, Current Deferred Compensation Liability, Current, Total Accounts receivable Increase (Decrease) in Accounts Receivable Restructuring and Related Activities [Abstract] Increase (Decrease) in Other Operating Liabilities, Total Other liabilities Increase (Decrease) in Other Operating Liabilities Retirement Benefits Retirement Benefits [Text Block] Payments to Acquire Businesses, Gross Acquisitions, cash payment Other income, net [Member] Other Expense [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Value of remaining settlement amount Value of Remaining Settlement Amount Value of remaining settlement amount. CRB [Member] Corporate Risk And Broking [Member] Corporate risk and broking. Divested Businesses Divested Businesses [Member] Divested Businesses [Member] Local Phone Number Local Phone Number Designated [Member] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Fiduciary assets Fiduciary assets. Fiduciary Assets [Member] Goodwill, Total Goodwill Goodwill, net, beginning balance Goodwill, net, ending balance Goodwill Statement of Cash Flows [Abstract] Loss Contingency, Estimated Recovery from Third Party Business interruption losses coverage Thereafter Finite Lived Intangible Assets Amortization Expense After Year Four Finite lived intangible assets amortization expense after year four. Stock Repurchased and Retired During Period, Shares Shares repurchased (in shares) Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Outsourced administration [Member] Outsourced Administration [Member] Outsourced administration. Organization, Consolidation and Presentation of Financial Statements [Abstract] Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Risk And Uncertainties Policy [Text Block] Risk and uncertainties. Risks and Uncertainties of the Economic Environment Caused by the Pandemic Foreign currency translation [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Other income Other Income Ordinary shares, nominal value Common Stock, Par or Stated Value Per Share Service Service [Member] Deferred compensation plan liability Deferred Compensation Liability, Classified, Noncurrent Deferred Compensation Liability, Classified, Noncurrent, Total Stated interest rate Debt Instrument, Interest Rate, Stated Percentage 4.500% senior notes due 2028 [Member] Senior Notes Due2028045 [Member] Senior notes due 2028, 045. Great Britain [Member] Great Britain [Member] Great Britain. Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Maximum [Member] Maximum [Member] Ordinary shares and APIC [Member] Common Stock Including Additional Paid in Capital [Member] Pension and Other Postretirement Benefits Expense (Reversal of Expense), Noncash, Total Net periodic benefit of defined benefit pension plans Pension and Other Postretirement Benefits Expense (Reversal of Expense), Noncash Earnings Per Share, Diluted [Abstract] Diluted earnings per share: Consolidation Items Consolidation Items [Domain] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Reduction of non-controlling interests (ii) Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Ownership Ownership [Domain] Fiduciary cash transferred. Fiduciary Cash Transferred Fiduciary Cash Transferred Service cost Defined Benefit Plan, Service Cost Total non-current assets Assets, Noncurrent Other current liabilities Other Sundry Liabilities, Current Cash consideration from other divestitures Proceeds from Divestiture of Businesses, Net of Cash Divested Proceeds from Divestiture of Businesses, Net of Cash Divested, Total Retirement Plan Sponsor Location Retirement Plan Sponsor Location [Domain] Operating Segments [Member] Operating Segments [Member] Current portion of long term debt Other Long-Term Debt, Current Segment Information Segment Reporting Disclosure [Text Block] City Area Code City Area Code CASH FLOWS FROM OPERATING ACTIVITIES Net Cash Provided by (Used in) Operating Activities [Abstract] Consolidation Items Consolidation Items [Axis] 3.875% senior notes due 2049 [Member] Senior Notes Due204903875 [Member] Senior notes due 2049, 03875. Business Acquisition [Line Items] Amount of unrecognized tax benefits including interest. Unrecognized Tax Benefits Including Interest Liabilities for uncertain tax positions Weighted Average Number of Shares Outstanding, Basic, Total Basic average number of shares outstanding (shares) Weighted Average Number of Shares Outstanding, Basic Deferred Revenue [Domain] Restructuring and Related Costs [Table Text Block] Summary of Total Restructuring Costs Salaries and benefits Labor and Related Expense Net Cash Provided by (Used in) Financing Activities [Abstract] CASH FLOWS USED IN FINANCING ACTIVITIES Share-based compensation and net settlements Adjustments To Additional Paid In Capital Sharebased Compensation And Net Settlements Adjustments to additional paid in capital, sharebased compensation and net settlements. Dec 31, 2022 [Member] December Thirty One Two Thousand and Twenty Two [Member] December thirty one two thousand and twenty two. Hedge Funds [Member] Statement [Table] Statement [Table] Document Fiscal Period Focus Document Fiscal Period Focus Total non-current liabilities Liabilities, Noncurrent Income (Loss) from Equity Method Investments, Total Interest in earnings of associates and other investments Income (Loss) from Equity Method Investments United Kingdom [Member] UNITED KINGDOM Restructuring Charges [Member] Total Restructuring Costs [Member] Not Designated as Hedging Instrument [Member] Nondesignated [Member] Not Designated as Hedging Instrument [Member] Statement [Line Items] Statement [Line Items] R and B segment. R and B Segment [Member] R&B Segment [Member] Antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Settlements Balance as of beginning of period Balance as of end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Long-term service contract Period. Long Term Service Contract Period Long term service contract Period Portion of pension and OPEB obligation attributed to disclosed plans (as a percent) Defined Benefit Plans Percentage Of Obligation From Plans Defined benefit plans, percentage of obligation from plans. Software [Member] Software and Software Development Costs [Member] Total lease cost, net Lease, Cost Lease Cost Gains (losses) accruing to acquirer. Gains Losses Accruing To Acquirer Net losses receivable from Gallagher on Deferred Closing Net income payable to Gallagher on Deferred Closing Acquired renewal commission receivable current. Acquired Renewal Commission Receivable Current Acquired renewal commissions receivable Value of receivables in initial transfer. Value of Receivables in Initial Transfer Value of receivables in initial transfer Asset Class [Domain] Accounts receivable, net Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Shares outstanding [Member] Common Stock [Member] Business combination, contingent consideration, liability and deferred consideration, noncurrent. Business Combination Contingent Consideration Liability And Deferred Consideration Noncurrent Contingent and deferred consideration on acquisitions Debt Instrument [Line Items] Debt Instrument [Line Items] Cash and Cash Equivalents, at Carrying Value, Ending Balance Cash and Cash Equivalents, at Carrying Value, Beginning Balance Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Other current assets Other Assets, Current Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 2.950% senior notes due 2029 [Member] Senior Notes Due202902950 [Member] Senior notes due 2029, 02950. Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Unallocated, net Other Operating Income (Expense), Net Schedule of Current and Long-term Debt Schedule of Debt [Table Text Block] Number of shares receivable upon acquisition Number Of Shares Receivable Upon Acquisition Number of shares receivable upon acquisition. Treasury shares, at cost, 17,519 shares in 2022 Treasury Stock, Value, Ending Balance Treasury Stock, Value, Beginning Balance Treasury Stock, Value, Total Treasury Stock, Value Discontinued Operations and Disposal Groups [Abstract] Cover [Abstract] Proceeds from Issuance of Senior Long-Term Debt Senior notes issued Business combination fiduciary assets transferred. Business Combination Fiduciary Assets Transferred Fiduciary assets transferred Transition Services Agreement. Transition Services Agreement [Member] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Miscellaneous Other Non Operating Income Expense Miscellaneous other non-operating income expense. Document Fiscal Year Focus Document Fiscal Year Focus Accumulated Other Comprehensive Loss Comprehensive Income (Loss) Note [Text Block] Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration] IRR [Member] Investment Risk And Reinsurance [Member] Investment, risk and reinsurance. Other [Member] Product and Service, Other [Member] Interest payable Interest Payable, Current Corporate income and other taxes Income Taxes Receivable, Current Restructuring Plan [Domain] Segment Reporting [Abstract] Proceeds from Divestiture of Businesses Proceeds from sale of operations Security Exchange Name Security Exchange Name Net current-period other comprehensive (loss)/income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Preferred Stock, Shares Issued, Total Preference shares, shares issued Preferred Stock, Shares Issued Preference shares, shares authorized Preferred Stock, Shares Authorized Capital Expenditures. Capital Expenditures [Member] Capital Expenditures [Member] Client relationships [Member] Customer Relationships [Member] Schedule Of Finite Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Hedging Designation Hedging Designation [Domain] Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] Accrued retirement benefits Accrued Employee Benefits, Current Entity Emerging Growth Company Entity Emerging Growth Company Amendment Flag Amendment Flag Notes receivable repayable by purchaser Financing Receivable, before Allowance for Credit Loss, Noncurrent Long-term note receivable Percentage of ownership by parent Subsidiary, Ownership Percentage, Parent Pension benefits assets Assets for Plan Benefits, Defined Benefit Plan Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Amortization of right-of-use assets Finance Lease, Right-of-Use Asset, Amortization Schedule of Future Estimated Amortization Expense for Amortizable Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Restructuring and Related Activities Disclosure [Text Block] Restructuring Costs Leases [Abstract] Other current liabilities excluded from held for sale. Other current liabilities excluded from held for sale (Loss)/gain reclassified from Accumulated OCL into income (effective element) Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total (Loss)/gain reclassified from Accumulated OCL into income (effective element) Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Interest income Interest Income Interest Income. Reclassification from AOCI, Current Period, Tax, Total Reclassification from AOCI, Current Period, Tax Reclassification from AOCI, Current Period, Tax Entity File Number Securities Act File Number Projected annual cost savings by end of 2024. Projected Annual Cost Savings by End of 2024 [Member] Projected Annual Cost Savings by End of 2024 [Member] Line of credit maturity date Line of Credit Facility, Expiration Date Dispositions [Abstract] Dispositions. Deferred Compensation Plan Assets Deferred compensation plans Goodwill and Intangible Assets Disclosure [Abstract] Other operating expenses Disposal Group Including Discontinued Operation Other Operating Expense Disposal group including discontinued operation other operating expense. Long-term Debt, Excluding Current Maturities, Total Long-term debt, excluding current maturities Long-term debt Long-Term Debt, Excluding Current Maturities Transaction and transformation Business Combination Integration Related Costs Credits Business combination integration related costs credits. Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Total CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Cash, cash equivalents and restricted cash Fees earned under service agreement. Fees earned under service agreement Federal Action [Member] Federal Action [Member] Federal Action. Income/(loss) from discontinued operations, net of tax INCOME/(LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX Income/(loss) from discontinued operations, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Disposal Group Classification [Domain] Debt Instrument Debt Instrument [Axis] Fair Value [Member] Estimate of Fair Value Measurement [Member] Repayment of debt including interest Re payment of debt Debt Instrument, Periodic Payment Debt Instrument, Periodic Payment, Total Total costs of providing services Costs and Expenses Entity Address, Address Line Two Entity Address, Address Line Two Schedule Of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Entity Small Business Entity Small Business Entity Shell Company Entity Shell Company Number of operating segments Number of Operating Segments Net periodic pension and postretirement benefit credits Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Proceeds from Debt, Net of Issuance Costs Proceeds from debt, net of issuance costs Provisions Increase Decrease In Provision For Liabilities Increase decrease in provision for liabilities. Earnings Per Share Earnings Per Share [Text Block] Other non-current liabilities Other Sundry Liabilities, Noncurrent Trademark and trade name [Member] Trademarks and Trade Names [Member] June 30, 2023 [Member] June Thirty Two Thousand Twenty Three [Member] June thirty two thousand twenty three. Other Restricted Assets, Current Fiduciary funds (included in fiduciary assets) Entity Address, Address Line One Entity Address, Address Line One Corporate Corporate Segment [Member] Payments for (Proceeds from) Investments, Total Payments for (Proceeds from) Investments (Purchase)/sale of investments Benefit from deferred income taxes Deferred Income Tax Expense Benefit Including Discontinued Operations Deferred income tax expense benefit including discontinued operations. Total provision for liabilities Provision for liabilities Provision For Liabilities Non Current Provision for liabilities non current. Antidilutive Securities Antidilutive Securities [Axis] Total other current liabilities Other current liabilities Other Liabilities, Current AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest, Total Net income Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Supplementary Information for Certain Balance Sheet Accounts Supplemental Balance Sheet Disclosures [Text Block] Minority Interest [Table] Noncontrolling Interest [Table] Finite-Lived Intangible Assets, Gross, Total Finite-lived intangible assets, gross carrying amount Finite-Lived Intangible Assets, Gross Subsequent Event Type [Domain] Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent, Total Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent Non-current contract assets Income Statement Location Income Statement Location [Axis] Variable lease cost Variable Lease, Cost Value of obligation in initial transfer. Value of Obligation in Initial Transfer Value of obligation in initial transfer Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Obligations assumed Long-Term Debt, Type [Axis] NET INCOME NET INCOME Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Nonrecurring [Member] Fair Value, Nonrecurring [Member] Corporate, Non-Segment Corporate, Non-Segment [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fiduciary. Fiduciary [Member] Basic earnings/(loss) per share from discontinued operations, net of tax Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share, Total Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Total deferred revenue and accrued expenses Deferred revenue and accrued expenses Deferred Revenue And Accrued Liabilities Current Deferred revenue and accrued liabilities current. Fiduciary cash Member Fiduciary Cash [Member] Product and Service Product and Service [Axis] Title of 12(b) Security Title of 12(b) Security Finite-lived intangible assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture, Total Issuance of shares under employee stock compensation plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Salaries and benefits Disposal Group Including Discontinued Operation Salaries And Benefits Disposal group including discontinued operation salaries and benefits. Net Operating Income of the Reported Segments Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Capitalized software costs Payments to Develop Software Diluted earnings/(loss) per share from discontinued operations, net of tax Diluted earnings/(loss) per share from discontinued operations, net of tax Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Balance Sheet Date Balance Sheet Date [Axis] Balance sheet date. Other Comprehensive Income Loss Net Of Tax Including Portion Attributable To Nonredeemable Noncontrolling Interest Other comprehensive income (loss), net of tax including portion attributable to nonredeemable noncontrolling interest. Other comprehensive income (loss) Changes in the Net Carrying Amount of the Components of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Foreign exchange contracts [Member] Foreign Exchange Contract [Member] Litigation Status Litigation Status [Domain] Treasury Stock, Common [Member] Entity Address, Country Entity Address, Country CASH FLOWS USED IN INVESTING ACTIVITIES Net Cash Provided by (Used in) Investing Activities [Abstract] Carrying Value [Member] Reported Value Measurement [Member] Fair value significant transfers to or from Level 3 Fair Value Level Three Transfers Amount Fair value level three transfers amount. Contingent consideration fair value Other Significant Noncash Transaction, Value of Consideration Given Litigation Status Litigation Status [Axis] Derivative [Table] Derivative [Table] Other Cost and Expense, Operating, Total Other operating expenses Other Cost and Expense, Operating Weighted Average Number Diluted Shares Outstanding Adjustment, Total Dilutive effect of potentially issuable shares (shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Portion at Fair Value Measurement [Member] [Default] Portion at Fair Value Measurement [Member] Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other comprehensive (loss)/income before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Dividends declared per share Common Stock, Dividends, Per Share, Declared Reduction of non-controlling interests (ii) Noncontrolling Interest, Decrease from Deconsolidation Contract with Customer, Liability, Total Deferred revenue Contract with Customer, Liability Revolving15 Billion Dollar Credit Facility [Member] Revolving 15 Billion Dollar Credit Facility. Revolving15 Billion Dollar Credit Facility Member Reconciliation Of Operating Profit Loss From Segments To Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Cash and Cash Equivalents [Axis] Defined contribution plan, employer contribution Defined Contribution Plan, Employer Discretionary Contribution Amount Description of interest accrual date Debt Instrument Interest Accrual Date Description Debt instrument interest accrual date description. Remainder of 2023 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Technology modernization. Technology modernization [Member] Technology Modernization [Member] Schedule of Other Nonoperating Income Schedule of Other Nonoperating Income (Expense) [Table Text Block] Restructuring Plan [Axis] Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Ordinary shares, shares outstanding Common Stock, Shares, Outstanding Other Divestitures [Member] Other Divestitures [Member] Other divestitures. Time-based award [Member] Time Based Shares [Member] Time-based shares. Goodwill [Roll Forward] Goodwill [Roll Forward] Restructuring Costs, Total Restructuring Costs Total Contract with Customer, Asset and Liability Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Gain on disposal of operations Supplemental Cash Flow Elements [Abstract] Retirement Plan Type Retirement Plan Type [Axis] Effect on Future Cash Flows, Amount Restructuring, Expected future effects Income Statement Location Income Statement Location [Domain] (Loss)/gain recognized in OCI (effective element) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax (Loss)/gain recognized in OCI (effective element) Business Combination and Asset Acquisition [Abstract] Document Type Document Type Ownership Ownership [Axis] Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) International [Member] International [Member] International. Fair Value by Liability Class Fair Value by Liability Class [Domain] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Document Quarterly Report Document Quarterly Report Schedule of Net Periodic Benefit Cost Schedule of Net Benefit Costs [Table Text Block] Marketable Securities, Total Mutual funds / exchange traded funds Marketable Securities Counterparty Name Counterparty Name [Domain] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Disposal Group Classification [Axis] Derivative, notional amount Derivative, Notional Amount Transformation program. Transformation Program [Member] Transformation Program [Member] Net Cash Provided by (Used in) Financing Activities Net cash used in financing activities Compensation and Retirement Disclosure [Line Items] Compensation And Retirement Disclosure [Line Items] Compensation and retirement disclosure. Long-term debt, excluding current maturities Other Long-Term Debt, Noncurrent Leases Lessee Operating And Finance Lease Disclosure [Text Block] The entire disclosure for operating lease and finance lease by the lessee. Entity Filer Category Entity Filer Category Other Current Liabilities [Table Text Block] Schedule of Other Current Liabilities Non-fiduciary cash member Non-Fiduciary Cash [Member] Repayment of debt including accrued interest Debt Instrument, Periodic Payment, Interest 5.050% senior notes due 2048 [Member] Senior Notes Due20480505 [Member] Senior notes due 2048, 0505. Balance Sheet Location [Domain] Ordinary shares, $0.000304635 nominal value [Member] Ordinary Share One [Member] Ordinary share one. Asset Class [Axis] Salaries and Benefits [Member] Salaries And Benefits [Member] Salaries and benefits. TOTAL LIABILITIES Liabilities Weighted average remaining life of amortizable intangible assets Finite-Lived Intangible Asset, Useful Life Accumulated Other Comprehensive Income Loss [Table] Accumulated Other Comprehensive Income (Loss) [Table] Asset Impairment Charges, Total Asset Impairment Charges Impairment Impairment Total WTW shareholders' equity Stockholders' equity attributable to parent, beginning balance Stockholders' equity attributable to parent, ending balance Equity, Attributable to Parent Number of countries in which entity operates (more than 140) Number of Countries in which Entity Operates Intangible Assets, Net (Excluding Goodwill), Total Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) NET INCOME ATTRIBUTABLE TO WTW Provisions for Liabilities Provisions For Liabilities Table [Text Block] Provisions for liabilities. Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Interest Expense, Total Interest expense Interest Expense Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total Contract asset, Current Contract with Customer, Asset, after Allowance for Credit Loss, Current Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Cash and Cash Equivalents [Domain] Fiduciary assets excluded from held-for-sale. Fiduciary Assets Excluded From Held For Sale Fiduciary assets excluded from held-for-sale Statement of Financial Position [Abstract] Basis of Presentation and Recent Accounting Pronouncements Basis of Presentation and Significant Accounting Policies [Text Block] Tax Legislation Tax Legislation [Policy Text Block] Tax legislation. Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture, Total Issuance of shares under employee stock compensation plans (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Derivative Liability, Statement of Financial Position [Extensible Enumeration] Diluted average number of shares outstanding (shares) Weighted Average Number of Shares Outstanding, Diluted Diluted average number of shares outstanding (shares) Credit Facility Credit Facility [Axis] Non-cash lease expense Operating Lease, Right-of-Use Asset, Periodic Reduction Claims, lawsuits and other proceedings Estimated Litigation Liability, Noncurrent Effective Income Tax Rate Reconciliation, Percent, Total Effective tax rate Effective Income Tax Rate Reconciliation, Percent Other Income and Expenses [Abstract] Prepaid expense and accrue revenue receivable current. Prepaid Expense And Accrued Revenue Receivable Current Prepayments and accrued income Income (Loss) from Continuing Operations, Per Outstanding Share, Total Income (Loss) from Continuing Operations, Per Basic Share Income from continuing operations per share Basic earnings per share from continuing operations attributable to WTW Deferred Revenue and Accrued Expenses Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Net periodic benefit (income)/cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Maximum expected service period. Maximum expected service period Income Taxes Income Tax Disclosure [Text Block] Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Risk and Broking. Risk and Broking [Member] R&B [Member] R&B [Member] Total interest and other income Interest and other income Interest and Other Income Derivative Asset, Total Derivative financial instruments Derivative assets, fair value Derivative Asset Finite Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Miller [Member] Miller [Member] Miller. Schedule of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Disaggregation Of Revenue [Line Items] Disaggregation of Revenue [Line Items] Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] Fair Value Disclosures [Abstract] Costs of providing services Costs and Expenses [Abstract] Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income/(loss) before non-controlling interests Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Measurement Frequency Measurement Frequency [Domain] Hedging Designation Hedging Designation [Axis] Market insurance premium. Insurance Premium Premiums to the insurance market Interest on lease liabilities Finance Lease, Interest Expense Type of Restructuring [Domain] Business Acquisition Business Acquisition [Axis] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Beginning Balance Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Ending Balance Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations Total cash, cash equivalents and restricted cash Total cash, cash equivalents and restricted cash Derivative instruments [Member] AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member] Income Tax Disclosure [Abstract] Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] North America [Member] North America [Member] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Health, Wealth and Career Health, Wealth and Career [Member] HWC [Member] HWC [Member] Retirement Plan Sponsor Location Retirement Plan Sponsor Location [Axis]