Statement of Cash Flows [Abstract]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Adjustments to reconcile net income to total net cash provided by operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Net gain on disposal of operations and fixed and intangible assets
Gain (Loss) on Disposition of Other Assets
Depreciation expense
Depreciation
Amortization of intangible assets
Amortization of Intangible Assets
Amortization of cash retention awards
Amortization Of Cash Retention Awards
Amortization of cash retention awards.
Net periodic income of defined benefit pension plans
Defined Benefit Plan, Net Periodic Benefit Cost
Provision for doubtful debts
Provision for Doubtful Accounts
Net movement in deferred taxes
Increase (Decrease) in Deferred Income Taxes
Excess tax benefits from share-based payment arrangements
Excess Tax Benefit from Share-based Compensation, Operating Activities
Share-based compensation
Share-based Compensation
Gain on derivative instruments
Noncash movement on derivative instruments
Noncash movement on derivative instruments going through the income statement
Undistributed earnings of associates
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions
Effect of exchange rate changes on net income
Foreign Currency Transaction Gain (Loss), Unrealized
Change in operating assets and liabilities, net of effects from purchase of subsidiaries:
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable
Increase (Decrease) in Accounts Receivable
Fiduciary assets
Change in Fiduciary Assets
Change in fiduciary assets within the reporting period.
Fiduciary liabilities
Change In Fiduciary Liabilities
Change in fiduciary liabilities within the reporting period.
Cash incentives paid
Annual Cash Incentive Payments
Annual cash incentive payments made to employees.
Funding of defined benefit pension plans
Increase (Decrease) in Pension Plan Obligations
Other assets
Increase (Decrease) in Other Operating Assets
Other liabilities
Increase (Decrease) in Other Operating Liabilities
Movement on provisions
Increase Decrease In Provisions
The increase (decrease) during the reporting period in provisions not separately disclosed in the statement of cash flows.
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
CASH FLOWS FROM INVESTING ACTIVITIES
Net Cash Provided by (Used in) Investing Activities [Abstract]
Proceeds on disposal of fixed and intangible assets
Proceeds from Sale of Productive Assets
Additions to fixed assets
Payments to Acquire Property, Plant, and Equipment
Payments to Acquire Intangible Assets
Payments to Acquire Intangible Assets
Acquisitions of operations, net of cash acquired
Payments to Acquire Businesses, Net of Cash Acquired
Payments to acquire other investments, net of distributions received
Payments to Acquire Other Investments
Proceeds on sale of operations, net of cash disposed
Proceeds from Divestiture of Businesses, Net of Cash Divested
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from Unsecured Lines of Credit
Proceeds from Unsecured Lines of Credit
Debt issuance costs
Payments of Debt Issuance Costs
Repayments of debt
Repayments of Other Debt
Repurchase of shares
Payments for Repurchase of Common Stock
Proceeds from issue of shares
Proceeds from Issuance of Common Stock
Excess tax benefits from share-based payment arrangements
Excess Tax Benefit from Share-based Compensation, Financing Activities
Dividends paid
Payments of Ordinary Dividends, Common Stock
Payments to Acquire Additional Interest in Subsidiaries
Payments to Acquire Additional Interest in Subsidiaries
Dividends paid to noncontrolling interests
Payments of Ordinary Dividends, Noncontrolling Interest
Net cash provided by (used in) financing activities
Net Cash Provided by (Used in) Financing Activities
DECREASE IN CASH AND CASH EQUIVALENTS
Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect
Effect of exchange rate changes on cash and cash equivalents
Effect of Exchange Rate on Cash and Cash Equivalents
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD
Cash and Cash Equivalents, at Carrying Value
CASH AND CASH EQUIVALENTS, END OF PERIOD
Statement of Financial Position [Abstract]
Statement [Table]
Statement [Table]
Class of Stock [Axis]
Class of Stock [Axis]
Class of Stock [Domain]
Class of Stock [Domain]
Nominal Value In Dollars [Member]
Nominal Value In Dollars [Member]
Nominal value in dollars.
Nominal Value In Euros [Member]
Nominal Value In Euros [Member]
Nominal value in Euros.
Statement [Line Items]
Statement [Line Items]
Ordinary shares, nominal value
Common Stock, Par or Stated Value Per Share
Ordinary shares, shares authorized
Common Stock, Shares Authorized
Common Stock, Shares, Issued
Common Stock, Shares, Issued
Preference shares, nominal value
Preferred Stock, Par or Stated Value Per Share
Preference shares, shares authorized
Preferred Stock, Shares Authorized
Preference shares, shares issued
Preferred Stock, Shares Issued
Treasury shares, nominal value
Treasury Stock Nominal Value
Treasury stock, nominal value.
Treasury stock, shares
Treasury Stock, Shares
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Condensed Financial Statements [Table]
Condensed Financial Statements [Table]
Legal Entity [Axis]
Legal Entity [Axis]
Entity [Domain]
Entity [Domain]
Willis North America, Inc. [Member]
Willis North America Inc [Member]
Willis north America, inc.
Condensed Financial Statements, Captions [Line Items]
Condensed Financial Statements, Captions [Line Items]
Senior Notes
Senior Notes
Senior notes, outstanding balance
Senior Notes, Noncurrent
Document Documentand Entity Information [Abstract]
Document Documentand Entity Information [Abstract]
Document Type
Document Type
Amendment Flag
Amendment Flag
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Trading Symbol
Trading Symbol
Entity Registrant Name
Entity Registrant Name
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Entity Filer Category
Entity Filer Category
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Willis Group Holdings
Parent Company [Member]
Guarantor companies
Guarantor Companies [Member]
Guarantor Companies [Member]
The Issuer
Trinity Acquisition Limited [Member]
Trinity Acquisition Limited
Other
Non-Guarantor Subsidiaries [Member]
Consolidating adjustments
Consolidation entries [Member]
Consolidation entries [Member]
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Subsequent Events [Abstract]
Subsequent Event [Table]
Subsequent Event [Table]
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event
Subsequent Event [Member]
Investment, Name [Axis]
Investment, Name [Axis]
Investment, Name [Domain]
Investment, Name [Domain]
Miller [Member]
Miller [Member]
Miller [Member]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Percentage of ownership percentage sold
Noncontrolling Interest, Sale Of Ownership Percentage By Parent
Noncontrolling Interest, Sale Of Ownership Percentage By Parent
Willis' interest in Miller (as a percent)
Noncontrolling Interest, Ownership Percentage by Parent
Purchase consideration to acquire business
Payments to Acquire Businesses, Gross
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table]
Schedule of Goodwill [Table]
Consolidation Items [Axis]
Consolidation Items [Axis]
Consolidation Items [Domain]
Consolidation Items [Domain]
Segments [Axis]
Segments [Axis]
Segments [Domain]
Segments [Domain]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Goodwill [Line Items]
Goodwill [Line Items]
Changes in Carrying Amount of Goodwill by Segment
Schedule of Goodwill [Table Text Block]
Earnings Per Share [Abstract]
EARNINGS PER SHARE
Earnings Per Share [Text Block]
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table]
Schedule of Defined Benefit Plans Disclosures [Table]
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis]
Defined Benefit Plans and Other Postretirement Benefit Plans [Axis]
Defined Benefit Plans and Other Postretirement Benefit Plans [Domain]
Defined Benefit Plan and Other Postretirement Benefit Plan [Domain]
UK Defined Benefit Pension Plan [Member]
Domestic Pension Plan of Foreign Entity [Member]
US Defined Benefit Pension Plans [Member]
United States Pension Plan of US Entity [Member]
International and US non-qualified Defined Benefit Pension Plans [Member]
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Cash contributions made to defined benefit pension plans
Defined Benefit Plan, Contributions by Employer
Employee cash contributions made to defined benefit pension plans
Defined Benefit Plan, Contributions by Plan Participants
Estimated contributions made to defined benefit pension plans
Estimated Contributions Made To Defined Benefit Pension Plans In Current Fiscal Year
Estimated contributions made to defined benefit pension plans in current fiscal year.
Contribution related to on going calculations
Defined Benefit Plan Estimated Employer Contributions In Current Fiscal Year Based On Pensionable Salaries
The employer's best estimate, as soon as it can be reasonably determined, of normal contributions expected to be paid to the plan in the full current fiscal period based on plan members' pensionable salaries. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.
Contribution rate for normal on-going contributions
Percentage Of On Going Contribution As Percentage Of Members Pensionable Salaries
Percentage of active plan members' pensionable salary required to calculate the normal on-going contributions.
Contributions towards funding the deficit
Defined Benefit Plan Estimated Employer Contributions In Current Fiscal Year Relating To Funding Deficit
The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan in the full current fiscal period relating to funding the deficit. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.
Exceptional return contribution in the current fiscal year
Exceptional return contribution in the current fiscal year
Exceptional return contribution in the current fiscal year
Percentage of exceptional return calculations made to shareholders
Contingent Pension Commitment Exceptional Shareholder Returns
Percentage of exceptional return calculations made to shareholders
Stock repurchased during share buyback program
Stock Repurchased During Period, Value
Percentage of contribution based on profit share calculation expected for the current fiscal year
Contingent Pension Commitment Profit
Percentage of contribution based on profit share calculation expected for the current fiscal year
EBITDA required to trigger additional profit share contributions
Earnings Before Interest Tax Depreciation And Amortization
Earnings before interest, tax, depreciation and amortization.
Maximum aggregate deficit funding and contingent contributions through to 31st December 2017
Maximum aggregate deficit funding and contingent contributions through to 31st December 2017
Maximum aggregate deficit funding and contingent contributions through to 31st December 2017
Maximum contributions payable from deficit funding contributions and profit share contributions over the six years ended December 31, 2017
Maximum Contributions Payable
Maximum Contributions Payable
Date of announcement of UK Defined Benefit pension amendment
Date of announcement of UK Defined Benefit pension amendment
Date of announcement of UK Defined Benefit pension amendment
Estimated full year employee contributions
Defined Benefit Plan Estimated Employee Contributions In Current Fiscal Year
Defined Benefit Plan Estimated Employee Contributions In Current Fiscal Year
Contributions made to defined benefit pension plans
Expected Defined Benefit Plan Contributions By Employer In Current Fiscal Year
Expected defined benefit plan contributions by employer in current fiscal year.
Defined Benefit Plan, Effect of Plan Amendment on Accumulated Benefit Obligation
Defined Benefit Plan, Effect of Plan Amendment on Accumulated Benefit Obligation
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Customer Relationships [Member]
Customer Relationships [Member]
Trade Names [Member]
Trade Names [Member]
Business Acquisition [Axis]
Business Acquisition [Axis]
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
Other Acquisitions [Domain]
Other Acquisitions [Domain]
Other Acquisitions [Domain]
All Current Year Acquisitions [Member]
All Current Year Acquisitions [Member]
All Current Year Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Percentage Ownership in Subsidiary
Percentage Ownership in Subsidiary
The percentage of ownership of common stock in the investee accounted for under the consolidation method of accounting.
Business Combination, Consideration Transferred
Business Combination, Consideration Transferred
Business Acquisition, Transaction Costs
Acquisition Costs, Period Cost
Payments to Acquire Businesses, Gross
Contingent and deferred consideration on acquisition
contingent or deferred consideration on acquisition (current)
Amount of contingent or deferred consideration on business combination due within 12 months
Business Combination, Deferred Consideration, Liability
Business Combination, Deferred Consideration, Liability
Amount of liability recognized arising from deferred consideration in a business combination.
Business Combination, Contingent Consideration, Liability
Business Combination, Contingent Consideration, Liability
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles
Finite-Lived Intangible Asset, Useful Life
Finite-Lived Intangible Asset, Useful Life
Goodwill
Goodwill
Total revenues
Revenues
NET (LOSS) INCOME
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Derivative Instrument Risk [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Interest Rate Swaps [Member]
Interest Rate Swap [Member]
Foreign Exchange Forward [Member]
Foreign Exchange Forward [Member]
Treasury Lock [Member]
Treasury Lock [Member]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax
Tax on Foreign Currency Translation Adjustment
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Foreign Currency Translation on Pension Funding Adjustments, Before Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Before Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Before Tax
Tax on Foreign Currency Translation on Pension Funding Adjustments
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Tax
Foreign Currency Translation on Pension Funding Adjustments, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Foreign Currency Translation on Pension Funding Adjustments, Net of Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, before Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, before Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit), Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit), Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax
Tax on amortization of unrecognized actuarial loss
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax
Amortization of unrecognized actuarial loss, Net of tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax
Amortization of unrecognized prior service gain, before Tax
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax
Tax on Amortization of unrecognized prior service gain
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax
Amortization of unrecognized prior service gain, Net of Tax
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax
Total Pension and Other Postretirement Benefit Plans, Adjustment, before Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax
Pension and Other Postretirement Benefit Plans, Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax
Net gain (loss) on derivative instruments, tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax
Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax
Reclassification Adjustment on Derivatives Included in Net Income, before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax
Reclassification Adjustment on Derivatives Included in Net Income, Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax
Derivatives Qualifying as Hedges, before Tax
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax
Derivatives Qualifying as Hedges, Tax
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax
Derivatives Qualifying as Hedges, Net of Tax
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax
Other Comprehensive Income (Loss), before Tax
Other Comprehensive Income (Loss), before Tax
Other comprehensive income, Tax
Other Comprehensive Income (Loss), Tax
Other Comprehensive Income (Loss), Net of Tax
Other Comprehensive Income (Loss), Net of Tax
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Subsequent Events [Text Block]
Subsequent Events [Text Block]
Other Income Expense [Abstract]
Other Income Expense [Abstract]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal
Effect of Exchange Rate Changes on Net Income
Effect of Exchange Rate Changes on Net Income
The aggregate unrealized foreign currency loss relating to the revaluation of the Group's net assets denominated in Venezuelan Bolivar Fuertes.
Foreign Currency Transaction Gain (Loss), Realized
Foreign Currency Transaction Gain (Loss), Realized
Other Nonoperating Income (Expense)
Other Nonoperating Income (Expense)
Restructuring and Related Activities [Abstract]
Schedule of Restructuring and Related Costs [Table]
Schedule of Restructuring and Related Costs [Table]
North America [Member]
North America [Member]
Corporate [Member]
Corporate, Non-Segment [Member]
International [Member]
International [Member]
International.
Restructuring Type [Axis]
Restructuring Type [Axis]
Type of Restructuring [Domain]
Type of Restructuring [Domain]
Contract Termination [Member]
Contract Termination [Member]
Others [Member]
Others [Member]
Others.
Restructuring Cost and Reserve [Line Items]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve [Roll Forward]
Restructuring Reserve [Roll Forward]
Beginning balance
Restructuring Reserve
Restructuring Costs
Restructuring Costs
Cash payments
Payments for Restructuring
Ending balance
Adjustments for Error Corrections [Axis]
Adjustments for Error Corrections [Axis]
Adjustments for Error Correction [Domain]
Adjustments for Error Correction [Domain]
Guarantor Subsidiaries
Guarantor Subsidiaries [Member]
Consolidating adjustments
Consolidating Adjustments [Member]
Consolidating adjustments.
Comprehensive income
Less: comprehensive income attributable to noncontrolling interests
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Major Classes of Amortizable Intangible Assets
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Estimated Aggregate Amortization of Intangible Assets for Each of Next Five Years
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Commissions and fees
Insurance Commissions and Fees
Gross Investment Income, Operating
Gross Investment Income, Operating
Other income
Other Income
Total revenues
Labor and Related Expense
Labor and Related Expense
Other Cost and Expense, Operating
Other Cost and Expense, Operating
Depreciation expense
Amortization of intangible assets
Restructuring Costs
Operating Expenses
Operating Expenses
Operating Income (Loss)
Operating Income (Loss)
Other income (expense), net
Income from group undertakings
Income from group undertakings
Income received in period from group undertakings
Expenses due to group undertakings
Expenses due to group undertakings
Expenses due in period to group undertakings
Interest Expense
Interest Expense
Income (loss) before income taxes and interest in earnings of associates
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest
Income Tax Expense (Benefit)
Income Tax Expense (Benefit)
Income Loss From Continuing Operations Before Interest In Earnings Of Associates
Income (Loss) From Continuing Operations Before Interest In Earnings Of Associates
Income (loss) from continuing operations before interest in earnings of associates.
Interest in earnings of associates, net of tax
Income (Loss) from Equity Method Investments
Equity account for subsidiaries
Equity Account For Subsidiaries
Equity account for subsidiaries.
Net Income (Loss) Attributable to Noncontrolling Interest
Net Income (Loss) Attributable to Noncontrolling Interest
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS
Net Income (Loss) Attributable to Parent
Net income attributable to Willis Group Holdings
Basic average number of shares outstanding
Weighted Average Number of Shares Outstanding, Basic
Dilutive effect of potentially issuable shares
Weighted Average Number Diluted Shares Outstanding Adjustment
Diluted average number of shares outstanding
Weighted Average Number of Shares Outstanding, Diluted
Income (Loss) from Continuing Operations, Per Basic Share
Income (Loss) from Continuing Operations, Per Basic Share
Net income attributable to Willis Group Holdings shareholders
Earnings Per Share, Basic
Dilutive Securities, Effect on Basic Earnings Per Share
Dilutive Securities, Effect on Basic Earnings Per Share
Income (Loss) from Continuing Operations, Per Diluted Share
Income (Loss) from Continuing Operations, Per Diluted Share
Net income attributable to Willis Group Holdings shareholders
Earnings Per Share, Diluted
Summary of Contractual Amounts of Company's Forward Contracts by Major Currency
Schedule of Foreign Exchange Contracts, Statement of Financial Position [Table Text Block]
Fair Value of Company's Derivative Financial Instruments and their Balance Sheet Classification
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Effects of Gains/(Losses) on Derivative Financial Instruments in Cash Flow Hedging Relationships on Consolidated Statements of Comprehensive Income and Consolidated Statements of Equity
Derivative Instruments, Gain (Loss) [Table Text Block]
Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table]
Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-Lived Intangible Assets [Line Items]
Financial Information for issuer, Parent guarantor, guarantor subsidiaries and non-guarantor subsidiaries [Text Block]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]
The Other Guarantors
Other Guarantors [Member]
Other guarantors.
The Issuer
Issuer [Member]
The issuer.
Consolidating adjustments
Consolidation, Eliminations [Member]
REVENUES
Revenues [Abstract]
EXPENSES
Operating Expenses [Abstract]
Salaries and benefits
Other operating expenses
Restructuring Costs
Operating Expenses
Segment operating income
Investment income from Group undertakings
Interest expense
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES
Income tax benefit (expense)
Net Cash Provided by (Used in) Operating Activities
Payments to Acquire Property, Plant, and Equipment
Payments to Acquire Businesses, Net of Cash Acquired
Payments to Acquire Other Investments
Cash received on intercompany investing activities
Cash received on intercompany investing activities
Cash received during period on intercompany investing activities
Cash paid on intercompany investing activities
Cash paid on intercompany investing activities
Cash paid in period on intercompany investing activities
Additional investment in subsidiaries
Additional investment in subsidiaries
Additional investment in subsidiaries
Proceeds from Other Debt
Proceeds from Other Debt
Repayments of Other Debt
Payments for Repurchase of Common Stock
Payments of Ordinary Dividends, Common Stock
Payments of Ordinary Dividends, Noncontrolling Interest
Cash received on intercompany financing activities
Cash received on intercompany financing activities
Cash received during period on intercompany financing activities
Cash paid on intercompany financing activities
Cash paid on intercompany financing activities
Cash paid during period on intercompany financing activities
Net cash used in financing activities
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS
CURRENT ASSETS
Assets, Current [Abstract]
Cash and cash equivalents
Accounts receivable, net
Accounts Receivable, Net, Current
Fiduciary assets
Fiduciary Assets
Fiduciary assets include uncollected premiums from insured and uncollected claims from insurers as well as cash and cash equivalents consisting primarily of time deposits that are held in a fiduciary capacity.
Deferred tax assets
Deferred Tax Assets, Net of Valuation Allowance, Current
Other current assets
Other Assets, Current
Amounts due from group undertakings
Amounts owed by group undertakings
Amounts owed by group undertakings
Total current assets
Assets, Current
NON-CURRENT ASSETS
Assets, Noncurrent [Abstract]
Investments in subsidiaries
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures
Fixed assets, net
Property, Plant and Equipment, Net
Other intangible assets, net
Finite-Lived Intangible Assets, Net
Investments in associates
Equity Method Investments
Deferred tax assets
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent
Pension benefits asset
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent
Other non-current assets
Other Assets, Noncurrent
Non-current amounts due from group undertakings
Noncurrent amounts owed by group undertakings
Noncurrent amounts owed by group undertakings
Total non-current assets
Assets, Noncurrent
TOTAL ASSETS
Assets
LIABILITIES AND STOCKHOLDERS' EQUITY
Liabilities and Equity [Abstract]
CURRENT LIABILITIES
Liabilities, Current [Abstract]
Fiduciary liabilities
Fiduciary Liabilities
Fiduciary liabilities include the obligation to remit uncollected premiums and uncollected claims/refunds to insurers and insured respectively.
Deferred revenue and accrued expenses
Deferred Revenue And Accrued Expenses
The carrying amount as of the balance sheet date of (1) consideration received or receivable on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income; and/or (2) the current portion of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy.
Income taxes payable
Accrued Income Taxes, Current
Short-term debt and current portion of long-term debt
Debt, Current
Deferred tax liabilities
Deferred Tax Liabilities, Net, Current
Other current liabilities
Other Liabilities, Current
Amounts due to group undertakings
Amounts due to group undertakings
Amounts due to group undertakings
Total current liabilities
Liabilities, Current
NON-CURRENT LIABILITIES
Liabilities, Noncurrent [Abstract]
Investments in subsidiaries
Net liability investments in subsidiaries
Net liability investments in subsidiaries
Long-term debt
Long-term Debt, Excluding Current Maturities
Liabilities for pension benefits
Defined Benefit Pension Plan, Liabilities, Noncurrent
Deferred tax liabilities
Deferred Tax Liabilities, Net, Noncurrent
Provisions for liabilities
Estimated Litigation Liability, Noncurrent
Other non-current liabilities
Other Liabilities, Noncurrent
Noncurrent amounts due to group undertakings
Noncurrent amounts due to group undertakings
Noncurrent amounts due to group undertakings
Total non-current liabilities
Liabilities, Noncurrent
Total liabilities
Liabilities
Redeemable Noncontrolling Interest, Equity, Carrying Amount
Redeemable Noncontrolling Interest, Equity, Carrying Amount
EQUITY
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Total Willis Group Holdings stockholders’ equity
Stockholders' Equity Attributable to Parent
Noncontrolling interests
Stockholders' Equity Attributable to Noncontrolling Interest
Total equity
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
TOTAL LIABILITIES AND EQUITY
Liabilities and Equity
Condensed Consolidated Statement of Comprehensive Income
Schedule of Condensed Statement of Comprehensive Income [Table Text Block]
Schedule of Condensed Statement of Comprehensive Income [Table Text Block]
Condensed Statement of Comprehensive Income [Table Text Block]
Condensed Statement of Comprehensive Income [Table Text Block]
Condensed Consolidating Statement of Operations
Condensed Consolidating Statement of Operations [Table Text Block]
Condensed consolidating statement of operations.
Condensed Consolidated Balance Sheet
Condensed Consolidated Balance Sheet Table [Text Block]
Condensed consolidated balance sheet.
Condensed Consolidating Statement of Cash Flows
Condensed Cash Flow Statement [Table Text Block]
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENT
Fair Value Disclosures [Text Block]
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES
Commitments and Contingencies Disclosure [Text Block]
Depreciation
Amortization of Intangible Assets
Basic and Diluted Earnings Per Share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
OTHER INTANGIBLE ASSETS, NET
Intangible Assets Disclosure [Text Block]
FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
Income Tax Disclosure [Abstract]
Components of Tax Charge
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Net cash used in financing activities
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD
Debt Disclosure [Abstract]
DEBT
Debt Disclosure [Text Block]
Other Assets [Abstract]
Analysis of Other Assets
Schedule of Other Assets [Table Text Block]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Hedging Relationship [Axis]
Hedging Relationship [Axis]
Hedging Relationship [Domain]
Hedging Relationship [Domain]
Cash Flow Hedging [Member]
Cash Flow Hedging [Member]
Derivatives, Fair Value, by Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Other Assets [Member]
Other Assets [Member]
Other Liabilities [Member]
Other Liabilities [Member]
Forward Exchange Contracts [Member]
Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivatives, Fair Value [Line Items]
Assets:
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative assets financial and hedging instruments, fair value
Derivative Asset, Fair Value, Gross Asset
Liabilities:
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative liabilities financial and hedging instruments, fair value
Derivative Liability, Fair Value, Gross Liability
Other Liabilities [Abstract]
Other current liabilities
Other Liabilities, Current [Abstract]
Accounts payable
Accounts Payable, Current
Accrued dividends payable
Dividends Payable, Current
Derivatives
Derivative Liability, Current
Deferred compensation plan liability
Deferred Compensation Liability, Current
Other payables
Other Sundry Liabilities, Current
Total other current liabilities
Other non-current liabilities
Other Liabilities, Noncurrent [Abstract]
Incentives from lessors
Accrued Rent, Noncurrent
Deferred compensation plan liability
Deferred Compensation Liability, Classified, Noncurrent
Contingent and deferred consideration on acquisition
contingent or deferred consideration on acquisition (noncurrent)
Amount of contingent or deferred consideration arising on business combination payable in more than 12 months
Derivatives
Derivative Liability, Noncurrent
Other payables
Other Sundry Liabilities, Noncurrent
Total other non-current liabilities
Total other liabilities
Other Liabilities
Assets and Liabilities Measured at Fair Value on Recurring Basis
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Summary of Estimated Fair Value of Company's Financial Instruments Held or Issued to Finance Company's Operations
Fair Value, by Balance Sheet Grouping [Table Text Block]
Foreign Currency Translation Adjustment in AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax
Pension and Other Postretirement Benefit Plans in AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax
Net unrealized gain on derivative instruments
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax
Foreign Currency Transaction and Translation Gain (Loss) IN AOCI Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent
Pension and Other Postretirement Benefit Plans, Adjustment in AOCI, before Reclassification Adjustments, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax
Unrealized Gain (Loss) on Derivatives in AOCI Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Before Reclassification Adjustments, Net of Tax
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax
Reclassification Adjustment on Foreign Currency Transaction and Translation Gain Loss Included in Net Income, Net of Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax
Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax
Other Comprehensive Income (Loss), Total Reclassification Adjustment on in Net Income, Net of Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Segment Reporting [Abstract]
SEGMENT INFORMATION
Segment Reporting Disclosure [Text Block]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Revolving Credit Facility [Member]
Revolving Credit Facility [Member]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Seven Year Term Loan Facility [Member]
Seven Year Term Loan Facility [Member]
Seven Year Term Loan Facility [Member]
Four Point One Two Five Percent Senior Notes Due Two Thousand Sixteen [Member]
Four Point One Two Five Percent Senior Notes Due Two Thousand Sixteen [Member]
Four point one two five percent senior notes due 2016.
Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [Member]
Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [Member]
Six point two percentage senior notes due 2017.
Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]
Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]
Seven percentage senior notes due 2019.
Five Point Seven Five Zero Senior Notes Due Two Thousand Twenty One [Member]
Five Point Seven Five Zero Senior Notes Due Two Thousand Twenty One [Member]
Five point seven five zero senior notes due two thousand twenty one.
Four Point Six Two Five Senior Notes Due Two Thousand Twenty Three [Member]
Four Point Six Two Five Senior Notes Due Two Thousand Twenty Three [Member]
Four Point Six Two Five Senior Notes Due Two Thousand Twenty Three [Member]
Six Point One Two Five Senior Notes Due Two Thousand Forty Three [Member]
Six Point One Two Five Senior Notes Due Two Thousand Forty Three [Member]
Six Point One Two Five Senior Notes Due Two Thousand Forty Three [Member]
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Long term debt
Loans Payable to Bank, Noncurrent
Interest rate
Debt Instrument, Interest Rate, Stated Percentage
Revolving credit facility
Long-term Line of Credit
Senior Notes, Noncurrent
Long-term debt, Total
Service cost
Defined Benefit Plan, Service Cost
Interest cost
Defined Benefit Plan, Interest Cost
Expected return on plan assets
Defined Benefit Plan, Expected Return on Plan Assets
Amortization of unrecognized prior service gain
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)
Defined Benefit Plan, Amortization of Gains (Losses)
Defined Benefit Plan, Amortization of Gains (Losses)
Net periodic benefit (income) cost
Other current assets
Other Current Assets [Abstract]
Other current assets.
Prepayments and accrued income
Prepaid Expense Other Assets And Unbilled Receivables Current
The total of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer, and the aggregate carrying amount of current assets, as of the balance sheet date, not separately presented elsewhere in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer); and 2) The amount due for services rendered or products shipped, but not yet billed, recognized in conformity with revenue recognition criteria.
Income tax receivable
Income Taxes Receivable, Current
Deferred compensation plan asset current
Deferred compensation plan asset current
Current element of carrying amount as of the balance sheet date of assets held under deferred compensation agreements
Derivative Asset
Derivative Asset
Other Receivables, Net, Current
Other Receivables, Net, Current
Total other current assets
Other non-current assets
Other Non Current Assets [Abstract]
Other non-current assets.
Deferred compensation plan assets
Deferred Compensation Plan Assets
Accounts Receivable, Net, Noncurrent
Accounts Receivable, Net, Noncurrent
Other Investments
Other Investments
Derivative Asset, Noncurrent
Derivative Asset, Noncurrent
Other receivables
Other Receivable Non Current
Carrying value as of the balance sheet date of non current assets that are expected to be realized or consumed after one year.
Total other non-current assets
Total other assets
Other Assets
Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table]
Derivative Instruments, Gain (Loss) [Table]
Balance Sheet Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
Interest Expense [Member]
Interest Expense [Member]
Derivative, by Nature [Axis]
Derivative, by Nature [Axis]
Derivative, Name [Domain]
Derivative, Name [Domain]
Foreign Exchange [Member]
Foreign Exchange [Member]
Senior Notes Due Two Thousand Fifteen [Member]
Senior Notes Due Two Thousand Fifteen [Member]
Senior notes due 2015.
Forward Contracts [Member]
Five Point Six Two Five Percent Senior Notes Due Two Thousand Fifteen [Member]
Five Point Six Two Five Percent Senior Notes Due Two Thousand Fifteen [Member]
Five point six two five percent senior notes due 2015.
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Asset, Fair Value, Gross Asset
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net
Statement, Business Segments [Axis]
Willis GB formerly Global [Member]
Willis GB formerly Global [Member]
Willis GB formerly Global [Member]
Capital, Wholesale & Reinsurance [Member]
Capital, Wholesale & Reinsurance [Member]
Capital, Wholesale & Reinsurance
Willis North America
Willis International
Goodwill, Gross
Goodwill, Gross
Goodwill, Impaired, Accumulated Impairment Loss
Goodwill, Impaired, Accumulated Impairment Loss
Goodwill, Net
Purchase price allocation adjustments
Goodwill, Purchase Accounting Adjustments
Goodwill acquired during the period
Goodwill, Acquired During Period
Goodwill disposed of during the year
Goodwill, Written off Related to Sale of Business Unit
Foreign exchange
Goodwill, Translation and Purchase Accounting Adjustments
Goodwill, Gross
Goodwill, Impaired, Accumulated Impairment Loss
Goodwill, Ending Balance
Derivative [Table]
Derivative [Table]
US Dollar [Member]
U S Dollar Contract [Member]
US dollar contract.
Euro [Member]
Euro Contract [Member]
Euro.
Japanese Yen [Member]
Japanese Yen Contract [Member]
Japanese yen.
Derivative [Line Items]
Derivative [Line Items]
Derivative, Notional Amount
Derivative, Notional Amount
Foreign Currency Fair Value Hedge Derivative at Fair Value
Foreign Currency Fair Value Hedge Derivative at Fair Value, Net
Components of Net Periodic Benefit (Income) Cost
Schedule of Net Benefit Costs [Table Text Block]
PENSION PLANS
Pension and Other Postretirement Benefits Disclosure [Text Block]
Components of Comprehensive Income
Comprehensive Income (Loss) [Table Text Block]
Components of Accumulated Other Comprehensive Loss, Net of Tax
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
Loss Contingencies [Table]
Loss Contingencies [Table]
Towers Watson [Member]
Towers Watson [Member]
Towers Watson [Member]
Other Commitments [Axis]
Other Commitments [Axis]
Other Commitments [Domain]
Other Commitments [Domain]
Net Rental [Member]
Net Rental [Member]
Net rental.
Trident V Parallel Fund [Member]
Trident V Parallel Fund [Member]
Trident V parallel fund.
Dowling Capital Partners I [Member]
Dowling Capital Partners I [Member]
Dowling Capital Partners I.
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Contractual Obligation
Contractual Obligation
Combined Equity after Merger
Combined Equity after Merger
Combined Equity after Merger
Capital commitments
Long-term Purchase Commitment, Amount
Capital contributions
Statement [Table]
Income Tax Examination [Table]
Minimum [Member]
Minimum [Member]
Maximum [Member]
Maximum [Member]
Scenario [Axis]
Scenario [Axis]
Scenario, Unspecified [Domain]
Scenario, Unspecified [Domain]
Scenario, Forecast [Member]
Scenario, Forecast [Member]
Income Tax Authority [Axis]
Income Tax Authority [Axis]
Income Tax Authority [Domain]
Income Tax Authority [Domain]
Non-US income tax authorities [Member]
Non-US income tax authorities [Member]
Non-US income tax authorities [Member]
UNITED STATES
UNITED STATES
Domestic Tax Authority [Member]
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Income Tax Examination [Line Items]
Ordinary income taxed at estimated annual effective tax rate, Income before tax
Ordinary Income Before Tax
Ordinary income (before significant one-off items) from continuing operations before tax.
Ordinary income taxed at estimated annual effective tax rate, Tax amount
Current Tax On Ordinary Income
Tax on ordinary income (before significant one-off items) from continuing operations.
Tax amount as reported
Effective tax rate as reported
Effective Income Tax Rate Reconciliation, Percent
Discontinued Operation, Tax (Expense) Benefit from Provision for (Gain) Loss on Disposal
Disposal group not discontinued operations tax on gain (loss) on disposal
The tax on the gain (loss) resulting from the sale of a disposal group that is not a discontinued operation. It is included in income from continuing operations before income taxes in the income statement.
Effective tax rate reconciliation percent from disposal of operation loss
Effective tax rate reconciliation percent from disposal of operation loss
Effective tax rate reconciliation percent from disposal of operation loss
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount
Net Adjustment In Respect Of Prior Periods Income Before Tax
Other Tax Expense (Benefit)
Additional tax charge as a result of changes to phasing
Additional tax charge as a result of changes to phasing
Additional tax charge as a result of changes to phasing
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Deferred Tax Assets, Gross
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount
Deferred Tax Assets, Valuation Allowance
Deferred Tax Assets, Valuation Allowance
Comprehensive Income (loss), Net of Tax, Including Portion Attributable to Noncontrolling Interests [Abstract]
Comprehensive Income (loss), Net of Tax, Including Portion Attributable to Noncontrolling Interests [Abstract]
Investment Income [Member]
Investment Income [Member]
Operating Expense [Member]
Operating Expense [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax
Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping [Table]
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurements, Recurring [Member]
Fair Value, Measurements, Recurring [Member]
Fair Value, Hierarchy [Axis]
Fair Value, Hierarchy [Axis]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Fair Value Hierarchy [Domain]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 2 [Member]
Measurement Basis [Axis]
Measurement Basis [Axis]
Fair Value Measurement [Domain]
Fair Value Measurement [Domain]
Portion at Fair Value Measurement [Member]
Portion at Fair Value Measurement [Member]
Fair Value [Member]
Estimate of Fair Value Measurement [Member]
Carrying Amount [Member]
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets:
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Liabilities:
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Current portion of long-term debt
Short Term Debt And Current Portion Of Long Term Debt
Short Term Debt And Current Portion Of Long Term Debt
Derivative financial instruments
Derivative Liability
Derivative Liability, Fair Value, Gross Liability
ASSETS
Assets [Abstract]
Total current assets
Total non-current assets
Liability for pension benefits
COMMITMENTS AND CONTINGENCIES
Commitments and Contingencies
REDEEMABLE NONCONTROLLING INTEREST
Ordinary shares
Common Stock, Value, Issued
Preference shares, $0.000115 nominal value; Authorized: 1,000,000,000; Issued nil shares in 2015 and 2014
Preferred Stock, Value, Issued
Additional paid-in capital
Additional Paid in Capital, Common Stock
Retained earnings
Retained Earnings (Accumulated Deficit)
Accumulated Other Comprehensive Income (Loss), Net of Tax
Treasury shares, at cost, 46,408 shares, $0.000115 nominal value, in 2015 and 2014 and 40,000 shares, €1 nominal value, in 2015 and 2014
Treasury Stock, Value
Total Willis Group Holdings stockholders’ equity
Fair Value Hierarchy [Domain]
Estimate of Fair Value Measurement [Member]
Variable Rate [Axis]
Variable Rate [Axis]
Variable Rate [Domain]
Variable Rate [Domain]
London Interbank Offered Rate (LIBOR) [Member]
London Interbank Offered Rate (LIBOR) [Member]
Federal Funds Purchased [Member]
Federal Funds Purchased [Member]
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Eurocurrency Rate Loans [Member]
Eurocurrency Rate Loans [Member]
Eurocurrency Rate Loans [Member]
Fair Value Adjustment On Five Point Six Two Five Percentage Senior Notes Due Two Thousand Fifteen [Member]
Fair Value Adjustment On Five Point Six Two Five Percentage Senior Notes Due Two Thousand Fifteen [Member]
Fair value adjustment on five point six two five percentage senior notes due 2015.
Currency Swap [Member]
Currency Swap [Member]
Senior Notes [Member]
Senior Notes [Member]
Revolving Credit Facility Four [Member]
Revolving Credit Facility Four [Member]
Revolving Credit Facility Four [Member]
Revolving Credit Facility Other [Member]
Revolving Credit Facility Other [Member]
Revolving Credit Facility Other [Member]
Debt Instrument, Face Amount
Debt Instrument, Face Amount
5-year term loan facility balance
Outstanding Term Loan Facility Balance
Outstanding term loan facility balance.
Maturity Period Of Term Loan
Maturity Period Of Term Loan
Maturity period of term loan.
Debt Instrument, Basis Spread on Variable Rate
Debt Instrument, Basis Spread on Variable Rate
Revolving credit facilities available
Line of Credit Facility, Maximum Borrowing Capacity
Debt Instrument, Maturity Date
Debt Instrument, Maturity Date
Number of Revolving Facilities
Line Of Credit Facility Quantity
Line of credit facility quantity.
Credit Facility restricted to regulatory purposes
Credit Facility restricted to regulatory purposes
Credit Facility restricted to regulatory purposes
Percentage of loan notes
Net derivative (gains) reclassified from accumulated comprehensive income into earnings within the next twelve months
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred
Schedule of Finite-Lived Intangible Assets by Major Class [Table]
Schedule of Finite-Lived Intangible Assets [Table]
Management contracts [Member]
Management contracts [Member]
Management contracts [Member]
Other Intangible Assets [Member]
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount
Finite-Lived Intangible Assets, Gross
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Net carrying amount
Amounts owed by group undertakings
Total liabilities
TOTAL LIABILITIES AND EQUITY
Schedule of Segment Reporting Information, by Segment [Table]
Schedule of Segment Reporting Information, by Segment [Table]
Corporate
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information [Line Items]
Operating Expenses
Costs and Expenses
Business Combination, Acquisition Related Costs
Business Combination, Acquisition Related Costs
Costs Related to Group Functions
Costs Related to Group Functions
Costs related to Group leadership costs and the cost of central functions such as Finance, HR etc
Non-servicing Element of Defined Benefit Plan
Non-servicing Element of Defined Benefit Plan
The total amount of net periodic benefit cost for defined benefit plans for the period excluding the servicing element. Periodic benefit costs include the following components: interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.
Other Expenses
Other Expenses
Senior notes issued
Proceeds from Issuance of Medium-term Notes
Statement of Stockholders' Equity [Abstract]
Common Stock by Currency [Axis]
Common Stock by Currency [Axis]
Common stock by currency.
All Currencies [Domain]
All Currencies [Domain]
United States of America, Dollars
United States of America, Dollars
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Parent [Member]
Parent [Member]
Irredeemable Noncontrolling Interest [Member]
Irredeemable Noncontrolling Interest [Member]
Irredeemable Noncontrolling Interest [Member]
Stockholders' Equity, Total [Member]
Stockholders' Equity, Total [Member]
Redeemable noncontrolling interest [Member]
Redeemable noncontrolling interest [Member]
Redeemable noncontrolling interest [Member]
Treasury Stock, Value
Total equity
Stock Repurchased During Period, Shares
Stock Repurchased During Period, Shares
Stock Repurchased During Period, Value
Dividends, Common Stock, Cash
Dividends, Common Stock, Cash
Other Comprehensive Income (Loss), Net of Tax
Exercise of Stock Options and Release of Non Vested Shares
Exercise of Stock Options and Release of Non Vested Shares
Exercise of stock options and release of non vested shares.
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options
Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition
Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition
Noncontrolling Interest, Increase from Sale of Parent Equity Interest
Noncontrolling Interest, Increase from Sale of Parent Equity Interest
Adjustments to Additional Paid In Capital, foreign exchange
Adjustments to Additional Paid In Capital, foreign exchange
Amount resulting from the process of expressing in the reporting currency adjustments to additional paid in capital denominated or measured in different currency
Short-Term Debt and Current Portion of Long-Term Debt
Schedule of Short-term Debt [Table Text Block]
Long-Term Debt
Schedule of Long-term Debt Instruments [Table Text Block]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Quoted Prices In Active Markets For Identical Assets Level 1 [Member]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Significant Other Unobservable Inputs Level 3 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value by Measurement Frequency [Axis]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets at fair value:
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments
Total assets
Assets, Fair Value Disclosure
Liabilities at fair value:
Liabilities, Fair Value Disclosure [Abstract]
Total liabilities
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Analysis of Other Liabilities
Other Liabilities [Table Text Block]
GOODWILL
Goodwill Disclosure [Text Block]
Derivative Instruments, Gain (Loss) by Income Statement Location [Axis]
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net
Other income expense [Text Block]
Other income expense [Text Block]
Other income expense [Text Block]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF OPERATIONS
Nature of Operations [Text Block]
Information Regarding Company's Segments
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Total Consolidated Operating Income
Consolidated Operating Income Table [Text Block]
Reconciliation of total consolidated operating income, as disclosed in the operating segment tables, to income before taxes and earnings of associates.
RESTRUCTURING COSTS
Restructuring and Related Activities Disclosure [Text Block]
Other income expense [Table Text Block]
Other income expense [Table Text Block]
Tabular disclosure of foreign exchange gains and losses, primarily from balance sheet revaluation, and gains and losses from the disposal of operations [Table Text Block]
OTHER ASSETS
Other Assets Disclosure [Text Block]
Restructuring and Related Costs
Restructuring and Related Costs [Table Text Block]
Schedule of Restructuring Reserve by Type of Cost
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Outstanding Time Based Stock Options
Outstanding Time Based Stock Options
Number of outstanding Time-based stock options outstanding at the end of the Reporting period.
Outstanding performance-based stock options
Outstanding Performance Based Stock Options
Number of outstanding Performance-based stock options outstanding at the end of the reporting period.
Restricted stock units outstanding
Restricted Stock Units Outstanding
Number of outstanding Restricted stock units outstanding at the end of the reporting period.
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Employee Stock Option [Member]
Employee Stock Option [Member]
Restricted Stock Units (RSUs) [Member]
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
Financial Information For Parent Issuer Guarantor Subsidiaries And Non Guarantor Subsidiaries [Text Block]
Financial information for parent issuer guarantor subsidiaries and non guarantor subsidiaries.
Willis GB [Member]
Willis GB [Member]
Willis GB [Member]
Total Segments
Operating Segments [Member]
Depreciation and amortization
Depreciation, Depletion and Amortization, Nonproduction
Schedule of Short-term Debt [Table]
Schedule of Short-term Debt [Table]
Short-term Debt, Type [Axis]
Short-term Debt, Type [Axis]
Short-term Debt, Type [Domain]
Short-term Debt, Type [Domain]
Term Loan Facility Expires Twenty Fifteen [Member]
Term Loan Facility Expires Twenty Fifteen [Member]
Term Loan Facility Expires Twenty Fifteen [Member]
Short-term Debt [Line Items]
Short-term Debt [Line Items]
Current portion of 7-year term loan facility expires 2018
Loans Payable to Bank, Current
Term loan period
Senior Notes, Current
Senior Notes, Current
OTHER LIABILITIES
Other Liabilities Disclosure [Text Block]
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS
Total consolidated operating income
Comprehensive Income (Loss) Note
Comprehensive Income (Loss) Note [Text Block]
Payments for Restructuring
INCOME TAXES
Income Tax Disclosure [Text Block]
Comprehensive income
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES
Basis of Presentation and Significant Accounting Policies [Text Block]
Income Statement [Abstract]
Operating Expenses
OPERATING INCOME
INCOME (LOSS) BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES
INCOME (LOSS) BEFORE INTEREST IN EARNINGS OF ASSOCIATES
NET INCOME (LOSS)
Less: net loss (income) attributable to noncontrolling interests
NET INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS
EARNINGS PER SHARE — BASIC AND DILUTED
Earnings Per Share, Basic and Diluted [Abstract]
— Basic earnings per share
— Diluted earnings per share
CASH DIVIDENDS DECLARED PER SHARE
Common Stock, Dividends, Per Share, Declared
Business Combination Disclosure [Text Block]
Business Combination Disclosure [Text Block]
Base rates loans [Member]
Base rates loans [Member]
Base rates loans [Member]
Final repayment for credit facility
Final Repayment For Credit Facility
Final repayment for credit facility.
Facility expiration date
Revolving credit facility outstanding balance at balance sheet date
Remainder of 2015
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year
2016
Finite-Lived Intangible Assets, Amortization Expense, Year Two
2017
Finite-Lived Intangible Assets, Amortization Expense, Year Three
2018
Finite-Lived Intangible Assets, Amortization Expense, Year Four
2019
Finite-Lived Intangible Assets, Amortization Expense, Year Five
Thereafter
Finite-Lived Intangible Assets, Amortization Expense, after Year Five