Willis Towers Watson Public Limited (WTW) 10-Q 5 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013
Document Documentand Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'WSH	'
Entity Registrant Name	'WILLIS GROUP HOLDINGS PLC	'
Entity Central Index Key	'0001140536	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	177,768,767

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
REVENUES	'	'	'	'
Commissions and fees	$791	$749	$2,722	$2,591
Investment income	4	4	11	14
Other income	0	1	3	4
Total revenues	795	754	2,736	2,609
EXPENSES	'	'	'	'
Salaries and benefits	-541	-502	-1,638	-1,508
Other operating expenses	-144	-146	-455	-431
Depreciation expense	-21	-21	-68	-59
Amortization of intangible assets	-14	-14	-42	-44
Net loss on disposal of operations	0	-1	0	-1
Total expenses	-720	-684	-2,203	-2,043
OPERATING INCOME	75	70	533	566
Gains (Losses) on Extinguishment of Debt	-60	0	-60	0
Interest expense	-30	-32	-93	-97
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-15	38	380	469
Income taxes	-11	-10	-88	-114
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	-26	28	292	355
Interest in earnings of associates, net of tax	-1	-2	11	12
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	303	367
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0	1
NET (LOSS) INCOME	-27	26	303	368
Less: net income attributable to noncontrolling interests	0	0	-6	-9
NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
Income (Loss) from Continuing Operations Attributable to Parent	($27)	$26	$297	$358
EARNINGS PER SHARE - BASIC AND DILUTED	'	'	'	'
— Basic earnings per share - continuing operations	($0.15)	$0.15	$1.70	$2.07
— Diluted earnings per share - continuing operations	($0.15)	$0.15	$1.67	$2.03
CASH DIVIDENDS DECLARED PER SHARE	$0.28	$0.27	$0.84	$0.81

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]	'	'	'	'
Comprehensive income	$46	$53	$345	$395
Less: comprehensive income attributable to noncontrolling interests	-1	0	-6	-9
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$45	$53	$339	$386

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
CURRENT ASSETS	'	'
Cash and cash equivalents	$623	$500
Accounts receivable, net	985	933
Fiduciary assets	9,197	9,271
Deferred tax assets	14	13
Other current assets	195	181
Total current assets	11,014	10,898
NON-CURRENT ASSETS	'	'
Fixed assets, net	472	468
Goodwill	2,846	2,827
Other intangible assets, net	361	385
Investments in associates	184	174
Deferred tax assets	6	18
Pension benefits asset	253	136
Other non-current assets	187	206
Total non-current assets	4,309	4,214
TOTAL ASSETS	15,323	15,112
CURRENT LIABILITIES	'	'
Fiduciary liabilities	9,197	9,271
Deferred revenue and accrued expenses	489	541
Income taxes payable	33	19
Short-term debt and current portion of long-term debt	17	15
Deferred tax liabilities	18	21
Other current liabilities	381	327
Total current liabilities	10,135	10,194
NON-CURRENT LIABILITIES	'	'
Long-term debt	2,315	2,338
Liability for pension benefits	229	282
Deferred tax liabilities	36	18
Provisions for liabilities	208	180
Other non-current liabilities	353	375
Total non-current liabilities	3,141	3,193
Total liabilities	13,276	13,387
COMMITMENTS AND CONTINGENCIES	'	'
EQUITY	'	'
Preference shares, $0.000115 nominal value; Authorized: 1,000,000,000; Issued nil shares in 2013 and 2012	0	0
Additional paid-in capital	1,258	1,125
Retained earnings	1,577	1,427
Accumulated other comprehensive loss, net of tax	-808	-850
Treasury shares, at cost, 46,408 shares, $0.000115 nominal value, in 2013 and 2012 and 40,000 shares, €1 nominal value, in 2013 and 2012	-3	-3
Total Willis Group Holdings stockholders’ equity	2,024	1,699
Noncontrolling interests	23	26
Total equity	2,047	1,725
TOTAL LIABILITIES AND EQUITY	15,323	15,112
Nominal Value In Dollars [Member]	'	'
EQUITY	'	'
Ordinary shares	0	0
Nominal Value In Euros [Member]	'	'
EQUITY	'	'
Ordinary shares	$0	$0

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012
	USD ($)	USD ($)	Nominal Value In Dollars [Member]	Nominal Value In Dollars [Member]	Nominal Value In Euros [Member]	Nominal Value In Euros [Member]
			USD ($)	USD ($)	EUR (€)	EUR (€)
Ordinary shares, nominal value	'	'	$0.00	$0.00	€ 1	€ 1
Ordinary shares, shares authorized	'	'	4,000,000,000	4,000,000,000	40,000	40,000
Ordinary shares, shares issued	'	'	177,299,202	173,178,733	40,000	40,000
Preference shares, nominal value	$0.00	$0.00	'	'	'	'
Preference shares, shares authorized	1,000,000,000	1,000,000,000	'	'	'	'
Preference shares, shares issued	0	0	'	'	'	'
Treasury shares, nominal value	'	'	$0.00	$0.00	€ 1	€ 1
Treasury stock, shares	'	'	46,408	46,408	40,000	40,000

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES	'	'
Net income	$303	$368
Adjustments to reconcile net income to total net cash provided by operating activities:	'	'
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	-1
Net gain on disposal of operations and fixed and intangible assets	-3	-2
Depreciation expense	68	59
Amortization of intangible assets	42	44
Amortization of cash retention awards	5	165
Net periodic (income) cost of defined benefit pension plans	-3	1
Provision for doubtful debts	3	9
Provision for deferred income taxes	18	47
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Operating Activities	-1	-2
Share-based compensation	31	24
Gain on derivative instruments	20	14
Redemption Premium	65	0
Undistributed earnings of associates	-3	-8
Effect of exchange rate changes on net income	-6	-10
Change in operating assets and liabilities, net of effects from purchase of subsidiaries:	'	'
Accounts receivable	-56	8
Fiduciary assets	27	-1,009
Fiduciary liabilities	-27	1,009
Cash incentives paid	-328	-304
Funding of defined benefit pension plans	-125	-115
Other assets	14	-37
Other liabilities	294	68
Movement on provisions	28	-18
Net cash provided by continuing operating activities	366	310
CASH FLOWS FROM INVESTING ACTIVITIES	'	'
Proceeds on disposal of fixed and intangible assets	9	8
Additions to fixed assets	-78	-97
Payments to Acquire Intangible Assets	-1	-1
Acquisitions of subsidiaries, net of cash acquired	-30	-4
Payments to acquire other investments	-5	-5
Net cash used in continuing investing activities	-105	-99
INCREASE IN CASH AND CASH EQUIVALENTS FROM OPERATING AND INVESTING ACTIVITIES	261	211
CASH FLOWS FROM FINANCING ACTIVITIES	'	'
Proceeds from draw down of revolving credit facilities	2	20
Proceeds from Issuance of Senior Long-term Debt	522	0
Payments of Debt Issuance Costs	-8	0
Repayments of debt	-532	-11
Payments of Debt Extinguishment Costs	-65	0
Repurchase of shares	0	-100
Proceeds from issue of shares	105	41
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	1	2
Dividends paid	-144	-139
Proceeds from Noncontrolling Interests	0	3
Acquisition of noncontrolling interests	-4	-29
Dividends paid to noncontrolling interests	-9	-11
Net cash used in continuing financing activities	-132	-224
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	129	-13
Effect of exchange rate changes on cash and cash equivalents	-6	1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	500	436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$623	$424

NATURE_OF_OPERATIONS

NATURE OF OPERATIONS	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
NATURE OF OPERATIONS	'
	NATURE OF OPERATIONS
	Willis provides a broad range of insurance and reinsurance broking and risk management consulting services to its clients worldwide, both directly and indirectly through its associates. The Company provides both specialized risk management advisory and consulting services on a global basis to clients engaged in specific industrial and commercial activities, and services to small, medium and large corporations through its retail operations.
	In its capacity as an advisor, insurance and reinsurance broker, the Company acts as an intermediary between clients and insurance carriers by advising clients on risk management requirements, helping clients determine the best means of managing risk, and negotiating and placing insurance risk with insurance carriers through the Company’s global distribution network.

BASIS_OF_PRESENTATION_AND_SIGN

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	'
	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES
	The accompanying condensed consolidated financial statements (‘Interim Financial Statements’) have been prepared in accordance with accounting principles generally accepted in the United States of America (‘US GAAP’).
	The Interim Financial Statements are unaudited but include all adjustments (consisting of normal recurring adjustments) which the Company’s management considers necessary for a fair presentation of the financial position as of such dates and the operating results and cash flows for those periods. Certain information and footnote disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted. However, the Company believes that the disclosures are adequate to make the information presented not misleading. The results of operations for the nine months ended September 30, 2013 may not necessarily be indicative of the operating results for the entire fiscal year.
	These Interim Financial Statements should be read in conjunction with the Company’s consolidated balance sheets as of December 31, 2012 and 2011, and the related consolidated statements of operations, comprehensive income, cash flows and changes in equity for each of the three years in the period ended December 31, 2012 included in the Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 28, 2013 (‘2012 10-K’) and as amended by Current Report on Form 8-K subsequently filed on August 8, 2013.
	In February 2013, the Financial Accounting Standards Board ('FASB') issued Accounting Standards Update ('ASU') No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income (ASU 2013-02). This guidance is the culmination of the FASB's deliberation on reporting reclassification adjustments from accumulated other comprehensive income (AOCI). The amendments in ASU 2013-02 do not change the current requirements for reporting net income or other comprehensive income but do require disclosure of amounts reclassified out of AOCI in its entirety, by component, on the face of the statement of operations or in the notes thereto. Amounts that are not required to be reclassified in their entirety to net income must be cross-referenced to other disclosures that provide additional detail. This standard is effective prospectively for annual and interim reporting periods beginning after December 15, 2012 and has been applied for this third quarter 2013 - see Note 16 - 'Comprehensive Income'.
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists - a consensus of the FASB Emerging Issues Task Force (ASU 2013-11) which provides guidance on financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward (NOL), or similar tax loss, or a tax credit carryforward exists. Such unrecognized tax benefits are required to be presented as a reduction of a deferred tax asset for a NOL or other tax credit carryforward whenever the NOL or tax credit carryforward would be available to reduce the additional taxable income or tax due if the tax position is disallowed.
	This standard is effective prospectively for annual and interim reporting periods beginning after December 15, 2013 although early adoption is permitted. The Company is currently evaluating the impact that adoption of this guidance will have on the consolidated financial statements.

SALARIES_AND_BENEFITS_EXPENSE

SALARIES AND BENEFITS EXPENSE	9 Months Ended
	Sep. 30, 2013
Compensation Related Costs [Abstract]	'
SALARIES AND BENEFITS EXPENSE	'
	SALARIES AND BENEFITS EXPENSE
	Severance Costs
	Severance costs arise in the normal course of business and these charges amounted to $2 million in the nine months ended September 30, 2013 (nine months ended September 30, 2012: $2 million). Of these costs, $nil was incurred in the three months ended September 30, 2013 (three months ended September 30, 2012: $nil).
	During the nine months ended September 30, 2013, the Company incurred additional salaries and benefits costs of $29 million, of which $28 million related to severance costs, in relation to an Expense Reduction Initiative in the first quarter. These costs related to 207 positions that have been eliminated.

INCOME_TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	The tables below reflect the components of the three and nine months ended September 30, 2013 and 2012 tax charge:
		Income			Tax			Effective tax
		before tax						rate
		(millions, except percentages)
	Three months ended September 30, 2013
	Non-US ordinary income taxed at estimated annual effective tax rate	$	45		$	(9	)	20	%
	US ordinary income and tax charge	(60		)	(4		)	(7	)%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	Benefit derived from the reduction in estimate of annual effective tax rate applied to ordinary income of the prior two quarters	—			1			—	%
	As reported	$	(15	)	$	(11	)	(73	)%
	Three months ended September 30, 2012
	Ordinary income taxed at estimated annual effective tax rate	$	39		$	(9	)	24	%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	Net adjustment in respect of prior periods	—			(3		)	—	%
	Non-tax deductible loss on disposal of operations	(1		)	—			—	%
	Benefit derived from the reduction in estimate of annual effective tax rate applied to ordinary income of the prior two quarters	—			1			—	%
	As reported	$	38		$	(10	)	26	%
		Income			Tax			Effective tax
		before tax						rate
		(millions, except percentages)
	Nine months ended September 30, 2013
	Non-US ordinary income taxed at estimated annual effective tax rate	$	386		$	(79	)	20	%
	US ordinary income and tax charge	(6		)	(10		)	(167	)%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	$	—		$	1		—	%
	As reported	$	380		$	(88	)	23	%
	Nine months ended September 30, 2012
	Ordinary income taxed at estimated annual effective tax rate	$	482		$	(117	)	24	%
	Items where tax effect is treated discretely:
	Write-off of uncollectible accounts receivable balance in North America	(12		)	5			41	%
	Net adjustment is respect of prior periods	—			(3		)	—	%
	Non-tax deductible loss on disposal of operations	(1		)	—			—	%
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	As reported	$	469		$	(114	)	24	%
	For interim income tax reporting purposes, the Company generally determines its best estimate of an annual effective tax rate and applies that rate to its year-to-date ordinary income. The Company's estimated annual effective tax rate excludes significant, unusual or infrequently occurring items and certain other items excluded pursuant to the US GAAP authoritative guidance where applicable. The income tax expense (or benefit) related to all other items is individually computed and recognized when the items occur.
	An $11 million tax expense was recorded on a pre-tax net loss of $15 million which was driven by the charges related to the early extinguishment of debt that was issued by Willis North America. As previously disclosed, the Company has maintained a valuation allowance against net US deferred tax assets. Therefore, no tax benefit was recognized for the debt extinguishment charges recorded during the quarter, resulting in a higher consolidated tax expense. When looking at the quarter’s results excluding the extinguishment charges, the tax rate was approximately 24 percent.
	For the nine months ended September 30, 2013, the reported tax rate was approximately 23 percent. The reported tax rate for the three and nine months ended September 30, 2012 was 26 percent and 24 percent, respectively.
	The Company's tax rate differs from the US statutory income tax rate of 35 percent primarily due to income being subject to tax in numerous non-US jurisdictions with varying tax rates, as well as the valuation allowance maintained in the US due to losses incurred in recent years.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
EARNINGS PER SHARE	'
	EARNINGS PER SHARE
	Basic and diluted earnings per share are calculated by dividing net income attributable to Willis Group Holdings by the average number of shares outstanding during each period. The computation of diluted earnings per share reflects the potential dilution that could occur if dilutive securities and other contracts to issue shares were exercised or converted into shares or resulted in the issuance of shares that then shared in the net income of the Company.
	In periods where losses are reported the weighted average shares outstanding excludes the potentially issuable shares described above, because their inclusion would be antidilutive.
	At September 30, 2013, time-based and performance-based options to purchase 7.8 million and 5.6 million shares (September 30, 2012: 9.2 million and 7.2 million), respectively, and 1.7 million restricted stock units (September 30, 2012: 1.2 million) were outstanding.
	Basic and diluted earnings per share are as follows:
		Three months ended September 30,					Nine months ended September 30,
		2013			2012		2013			2012
		(millions, except per share data)
	Net (loss) income attributable to Willis Group Holdings	$	(27	)	$	26	$	297		$	359
	Basic average number of shares outstanding	177			173		175			173
	Dilutive effect of potentially issuable shares	—			2		3			3
	Diluted average number of shares outstanding	177			175		178			176
	Basic earnings per share:
	Continuing operations	$	(0.15	)	$	0.15	$	1.7		$	2.07
	Discontinued operations	—			—		—			0.01
	Net (loss) income attributable to Willis Group Holdings shareholders	$	(0.15	)	$	0.15	$	1.7		$	2.08
	Dilutive effect of potentially issuable shares	—			—		(0.03		)	(0.04		)
	Diluted earnings per share:
	Continuing operations	$	(0.15	)	$	0.15	$	1.67		$	2.03
	Discontinued operations	—			—		—			0.01
	Net (loss) income attributable to Willis Group Holdings shareholders	$	(0.15	)	$	0.15	$	1.67		$	2.04
	Options to purchase 15.1 million and 3.8 million shares were not included in the computation of the dilutive effect of stock options for the three and nine months ended September 30, 2013 respectively because the effect was antidilutive (three and nine months ended September 30, 2012: 6.1 million and 6.2 million).

PENSION_PLANS

PENSION PLANS	9 Months Ended
	Sep. 30, 2013
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]	'
PENSION PLANS	'
	PENSION PLANS
	The components of the net periodic benefit (income) cost of the UK, US and international and US non-qualified defined benefit plans are as follows:
		Three months ended September 30,
		UK Pension						US Pension						International and US non-qualified Pension
		Benefits						Benefits						Benefits
		2013			2012			2013			2012			2013			2012
		(millions)
	Components of net periodic benefit (income) cost:
	Service cost	$	10		$	9		$	—		$	—		$	—		$	1
	Interest cost	26			27			10			11			2			1
	Expected return on plan assets	(47		)	(45		)	(13		)	(12		)	(2		)	(2		)
	Amortization of unrecognized prior service gain	(1		)	(1		)	—			—			—			—
	Amortization of unrecognized actuarial loss	11			9			3			2			—			—
	Net periodic benefit (income) cost	$	(1	)	$	(1	)	$	—		$	1		$	—		$	—
		Nine months ended September 30,
		UK Pension						US Pension						International and US non-qualified Pension
		Benefits						Benefits						Benefits
		2013			2012			2013			2012			2013			2012
		(millions)
	Components of net periodic benefit (income) cost:
	Service cost	$	28		$	26		$	—		$	—		$	2		$	3
	Interest cost	80			81			29			31			5			4
	Expected return on plan assets	(141		)	(135		)	(38		)	(35		)	(5		)	(5		)
	Amortization of unrecognized prior service gain	(4		)	(4		)	—			—			—			—
	Amortization of unrecognized actuarial loss	33			29			7			6			1			—
	Net periodic benefit (income) cost	$	(4	)	$	(3	)	$	(2	)	$	2		$	3		$	2
	During the nine months ended September 30, 2013, the Company made cash contributions of $68 million (2012: $60 million) into the UK defined benefit pension plan. This includes a $10 million payment that arose as a result of the share buyback program discussed below. In addition to this, a further payment of $9 million (2012: $9 million) was made in respect of employees’ salary sacrifice contributions. Cash contributions of $40 million and $8 million (2012: $40 million and $6 million) were made to the US plan and international and US non-qualified defined benefit pension plans, respectively.
	Contributions to the UK defined benefit pension plan in 2013 are expected to total $88 million, of which approximately $22 million relates to on-going contributions calculated as 15.9 percent of active plan members’ pensionable salaries, approximately $56 million relates to contributions towards funding the deficit and $10 million exceptional return payment related to 10 percent of the $100 million share buyback program completed during 2012, as required under the current agreed schedule of contributions.
	In addition, for full year 2013, the Company will contribute approximately $12 million to the UK defined benefit pension plan related to employees’ salary sacrifice contributions. The Company also expects to contribute approximately $40 million to the US plan and $11 million to the international and US non-qualified plans for the full year 2013 (inclusive of amounts contributed in the year to date).
	In addition, under the current schedule of contributions, further contributions will be payable based on a profit share calculation (equal to 20 percent of EBITDA in excess of $900 million per annum as defined by the revised schedule of contributions) and an exceptional return calculation (equal to 10 percent of any exceptional returns made to shareholders, for example, share buybacks and special dividends). Aggregate contributions under the deficit funding contribution and the profit share calculation are capped at £312 million ($505 million) over the six-year period ended December 31, 2017.
	The schedule of contributions is automatically renegotiated after three years and at any earlier time jointly agreed by the Company and the Trustee.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	COMMITMENTS AND CONTINGENCIES
	Contractual Obligations
	Pensions
	The Company’s pension funding obligations are set out in Note 6 — ‘Pension Plans’.
	Other Contractual Obligations
	In July 2010, the Company made a capital commitment of $25 million to Trident V Parallel Fund, LP. As of September 30, 2013 there had been approximately $15 million of capital contributions.
	In May 2011, the Company made a capital commitment of $10 million to Dowling Capital Partners I, LP. As of September 30, 2013 there had been approximately $2 million of capital contributions.
	Claims, Lawsuits and Other Proceedings
	In the ordinary course of business, the Company is subject to various actual and potential claims, lawsuits, and other proceedings relating principally to alleged errors and omissions in connection with the placement of insurance and reinsurance. Similar to other corporations, the Company is also subject to a variety of other claims, including those relating to the Company’s employment practices. Some of the claims, lawsuits and other proceedings seek damages in amounts which could, if assessed, be significant.
	Errors and omissions claims, lawsuits, and other proceedings arising in the ordinary course of business are covered in part by professional indemnity or other appropriate insurance. The terms of this insurance vary by policy year and self-insured risks have increased significantly in recent years. Regarding self-insured risks, the Company has established provisions which are believed to be adequate in the light of current information and legal advice, and the Company adjusts such provisions from time to time according to developments.
	On the basis of current information, the Company does not expect that the actual claims, lawsuits and other proceedings to which the Company is subject, or potential claims, lawsuits, and other proceedings relating to matters of which it is aware, will ultimately have a material adverse effect on the Company’s financial condition, results of operations or liquidity. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation and disputes with insurance companies, it is possible that an adverse outcome in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in particular quarterly or annual periods.
	The material actual or potential claims, lawsuits, and other proceedings, of which the Company is currently aware, are:
	Stanford Financial Group Litigation
	The Company has been named as a defendant in 13 similar lawsuits relating to the collapse of The Stanford Financial Group (‘Stanford’), for which Willis of Colorado, Inc. acted as broker of record on certain lines of insurance. The complaints in these actions generally allege that the defendants actively and materially aided Stanford’s alleged fraud by providing Stanford with certain letters regarding coverage that they knew would be used to help retain or attract actual or prospective Stanford client investors. The complaints further allege that these letters, which contain statements about Stanford and the insurance policies that the defendants placed for Stanford, contained untruths and omitted material facts and were drafted in this manner to help Stanford promote and sell its allegedly fraudulent certificates of deposit.
	The 13 actions are as follows:
	•	Troice, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:9-CV-1274-N, was filed on July 2, 2009 in the U.S. District Court for the Northern District of Texas against Willis Group Holdings plc, Willis of Colorado, Inc. and a Willis associate, among others. On April 1, 2011, plaintiffs filed the operative Third Amended Class Action Complaint individually and on behalf of a putative, worldwide class of Stanford investors, adding Willis Limited as a defendant and alleging claims under Texas statutory and common law and seeking damages in excess of $1 billion, punitive damages and costs. On May 2, 2011, the defendants filed motions to dismiss the Third Amended Class Action Complaint, arguing, inter alia, that the plaintiffs’ claims are precluded by the Securities Litigation Uniform Standards Act of 1998 (‘SLUSA’).
	On May 10, 2011, the court presiding over the Stanford-related actions in the Northern District of Texas entered an order providing that it would consider the applicability of SLUSA to the Stanford-related actions based on the decision in a separate Stanford action not involving a Willis entity, Roland v. Green, Civil Action No. 3:10-CV-0224-N. On August 31, 2011, the court issued its decision in Roland, dismissing that action with prejudice under SLUSA.
	On October 27, 2011, the court in Troice entered an order (i) dismissing with prejudice those claims asserted in the Third Amended Class Action Complaint on a class basis on the grounds set forth in the Roland decision discussed above and (ii) dismissing without prejudice those claims asserted the Third Amended Class Action Complaint on an individual basis. Also on October 27, 2011, the court entered a final judgment in the action.
	On October 28, 2011, the plaintiffs in Troice filed a notice of appeal to the U.S. Court of Appeals for the Fifth Circuit. Subsequently, Troice, Roland and a third action captioned Troice, et al. v. Proskauer Rose LLP, Civil Action No. 3:09-CV-01600-N, which also was dismissed on the grounds set forth in the Roland decision discussed above and on appeal to the U.S. Court of Appeals for the Fifth Circuit, were consolidated for purposes of briefing and oral argument. Following the completion of briefing and oral argument, on March 19, 2012, the Fifth Circuit reversed and remanded the actions. On April 2, 2012, the defendants-appellees filed petitions for rehearing en banc. On April 19, 2012, the petitions for rehearing en banc were denied. On July 18, 2012, defendants-appellees filed a petition for writ of certiorari with the United States Supreme Court regarding the Fifth Circuit's reversal in Troice. On January 18, 2013, the Supreme Court granted our petition and will hear our appeal. Opening briefs were filed on May 3, 2013 and the Supreme Court heard oral argument on October 7, 2013. We expect a ruling in late 2013 or early 2014.
	•	Ranni v. Willis of Colorado, Inc., et al., C.A. No. 9-22085, was filed on July 17, 2009 against Willis Group Holdings plc and Willis of Colorado, Inc. in the U.S. District Court for the Southern District of Florida. The complaint was filed on behalf of a putative class of Venezuelan and other South American Stanford investors and alleges claims under Section 10(b) of the Securities Exchange Act of 1934 (and Rule 10b-5 thereunder) and Florida statutory and common law and seeks damages in an amount to be determined at trial. On October 6, 2009, Ranni was transferred, for consolidation or coordination with other Stanford-related actions (including Troice), to the Northern District of Texas by the U.S. Judicial Panel on Multidistrict Litigation (the ‘JPML’). The defendants have not yet responded to the complaint in Ranni.
	•	Canabal, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:9-CV-1474-D, was filed on August 6, 2009 against Willis Group Holdings plc, Willis of Colorado, Inc. and the same Willis associate named as a defendant in Troice, among others, also in the Northern District of Texas. The complaint was filed individually and on behalf of a putative class of Venezuelan Stanford investors, alleged claims under Texas statutory and common law and sought damages in excess of $1 billion, punitive damages, attorneys’ fees and costs. On December 18, 2009, the parties in Troice and Canabal stipulated to the consolidation of those actions (under the Troice civil action number), and, on December 31, 2009, the plaintiffs in Canabal filed a notice of dismissal, dismissing the action without prejudice.
	•	Rupert, et al. v. Winter, et al., Case No. 2009C115137, was filed on September 14, 2009 on behalf of 97 Stanford investors against Willis Group Holdings plc, Willis of Colorado, Inc. and the same Willis associate, among others, in Texas state court (Bexar County). The complaint alleges claims under the Securities Act of 1933, Texas and Colorado statutory law and Texas common law and seeks special, consequential and treble damages of more than $300 million, attorneys’ fees and costs. On October 20, 2009, certain defendants, including Willis of Colorado, Inc., (i) removed Rupert to the U.S. District Court for the Western District of Texas, (ii) notified the JPML of the pendency of this related action and (iii) moved to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. On April 1, 2010, the JPML issued a final transfer order for the transfer of Rupert to the Northern District of Texas. On January 24, 2012, the court remanded Rupert to Texas State Court (Bexar County), but stayed the action until further order of the court. The defendants have not yet responded to the complaint in Rupert.
	•	Casanova, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:10-CV-1862-O, was filed on September 16, 2010 on behalf of seven Stanford investors against Willis Group Holdings plc, Willis Limited, Willis of Colorado, Inc. and the same Willis associate, among others, also in the Northern District of Texas. The complaint alleges claims under Texas statutory and common law and seeks actual damages in excess of $5 million, punitive damages, attorneys’ fees and costs. The defendants have not yet responded to the complaint in Casanova.
	•	Rishmague, et ano. v. Winter, et al., Case No. 2011CI2585, was filed on March 11, 2011 on behalf of two Stanford investors, individually and as representatives of certain trusts, against Willis Group Holdings plc, Willis of Colorado, Inc., Willis of Texas, Inc. and the same Willis associate, among others, in Texas state court (Bexar County). The complaint alleges claims under Texas and Colorado statutory law and Texas common law and seeks special, consequential and treble damages of more than $37 million and attorneys’ fees and costs. On April 11, 2011, certain defendants, including Willis of Colorado, Inc., (i) removed Rishmague to the Western District of Texas, (ii) notified the JPML of the pendency of this related action and (iii) moved to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. On August 8, 2011, the JPML issued a final transfer order for the transfer of Rishmague to the Northern District of Texas, where it is currently pending. The defendants have not yet responded to the complaint in Rishmague.
	•	MacArthur v. Winter, et al., Case No. 2013-07840, was filed on February 8, 2013 on behalf of two Stanford investors against Willis Group Holdings plc, Willis of Colorado, Inc., Willis of Texas, Inc. and the same Willis associate, among others, in Texas state court (Harris County). The complaint alleges claims under Texas and Colorado statutory law and Texas common law and seeks actual, special, consequential and treble damages of approximately $4 million and attorneys' fees and costs. On March 29, 2013, Willis of Colorado, Inc. and Willis of Texas, Inc. (i) removed MacArthur to the U.S. District Court for the Southern District of Texas and (ii) notified the JPML of the pendency of this related action. On April 2, 2013, Willis of Colorado, Inc. and Willis of Texas, Inc. filed a motion in the Southern District of Texas to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. Also on April 2, 2013, the court presiding over MacArthur in the Southern District of Texas transferred the action to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. The defendants have not yet responded to the complaint in MacArthur.
	•	Florida suits: On February 14, 2013, five law suits were filed against Willis Group Holdings plc, Willis Limited and Willis of Colorado, Inc. in Florida state court (Miami-Dade County) alleging violations of Florida common law. The five suits are: (1) Barbar, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05666CA27, filed on behalf of 35 Stanford investors seeking compensatory damages in excess of $30 million; (2) de Gadala-Maria, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05669CA30, filed on behalf of 64 Stanford investors seeking compensatory damages in excess of $83.5 million; (3) Ranni, et ano. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05673CA06, filed on behalf of two Stanford investors seeking compensatory damages in excess of $3 million; (4) Tisminesky, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05676CA09, filed on behalf of 11 Stanford investors seeking compensatory damages in excess of $6.5 million; and (5) Zacarias, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05678CA11, filed on behalf of 10 Stanford investors seeking compensatory damages in excess of $12.5 million. On June 3, 2013, Willis of Colorado, Inc. removed all five cases to the Southern District of Florida and, on June 4, 2013, notified the JPML of the pendency of these related actions. On June 10, 2013, the court in Tisminesky issued an order sua sponte staying and administratively closing that action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation and coordination with the other Stanford-related actions. On June 11, 2013, Willis of Colorado, Inc. moved to stay the other four actions pending the JPML's transfer decision. On June 20, 2013, the JPML issued a conditional transfer order for the transfer of the five actions to the Northern District of Texas, the transmittal of which was stayed for seven days to allow for any opposition to be filed. On June 28, 2013, with no opposition having been filed, the JPML lifted the stay, enabling the transfer to go forward. The defendants have not yet responded to the complaints in these actions.
	•	Janvey, et al. v. Willis of Colorado, Inc., et al., Case No. 3:13-CV-03980-D, was filed on October 1, 2013 in the U.S. District Court for the Northern District of Texas against Willis Group Holdings plc, Willis Limited, Willis North America Inc., Willis of Colorado, Inc. and the same Willis associate. The complaint was filed (i) by Ralph S. Janvey, in his capacity as Court-Appointed Receiver for the Stanford Receivership Estate, and the Official Stanford Investors Committee (the ‘OSIC’) against all defendants and (ii) on behalf of a putative, worldwide class of Stanford investors against Willis North America Inc. Plaintiffs Janvey and the OSIC allege claims under Texas common law and the court’s Amended Order Appointing Receiver, and the putative class plaintiffs allege claims under Texas statutory and common law. Plaintiffs seek actual damages in excess of $1 billion, punitive damages and costs. The defendants have not yet responded to the complaint in Janvey.
	Additional actions could be brought in the future by other investors in certificates of deposit issued by Stanford and its affiliates. The Company disputes these allegations and intends to defend itself vigorously against these actions. The outcomes of these actions, however, including any losses or other payments that may occur as a result, cannot be predicted at this time.
	European Commission Sector Inquiry
	In 2006, the European Commission ('EC') issued questionnaires pursuant to its Sector Inquiry (or, in respect of Norway, the European Free Trade Association Surveillance Authority ('EFTAS')), related to insurance business practices, including compensation arrangements for brokers, to at least 150 European brokers including our operations in nine European countries. The Company filed responses to the questionnaires. On September 25, 2007, the EC and EFTAS issued a joint report expressing concerns over potential conflicts of interest in the industry relating to remuneration and binding authorities and also over the nature of the coinsurance market.
	The Company cooperated with both the EC and the EFTAS to resolve issues raised in their final joint report regarding coinsurance. In 2012, the EC appointed Ernst & Young to conduct a review of the coinsurance market and Ernst & Young approached one broking firm in each Member State. Three of our European subsidiaries (UK, Spain and the Netherlands) either met with Ernst & Young or received questionnaires from them on this matter in 2012. The EC published Ernst & Young's report on February 11, 2013, which described the nature and benefits of the coinsurance and subscription markets. The EC intends to consult further on these findings during 2013 before determining next steps.
	Regulatory Investigation
	In 2011, we and the UK Financial Services Authority (the 'FSA') announced a settlement for lapses by Willis Limited, our UK brokerage subsidiary, in its implementation and documentation of its controls to counter the risks of improper payments being made to non-FSA authorized overseas third parties engaged to help win business, particularly in high risk jurisdictions.
	As a result of an FSA settlement in 2011, we conducted a further internal review of certain high-risk payments made by our UK subsidiary between 2005 and 2009. We do not believe that this further internal review will result in any material fines or sanctions, but there can be no assurance that any resolution will not have an adverse impact on us or our ability to conduct our business in certain jurisdictions. While we believe that our current systems and controls are adequate and in accordance with all applicable laws and regulations, we cannot assure that such systems and controls will prevent any violations of applicable laws and regulations.

DERIVATIVE_FINANCIAL_INSTRUMEN

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES	'
	DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
	Fair Value of Derivative Financial Instruments
	In addition to the note below, see Note 9 — ‘Fair Value Measurement’ for information about the fair value hierarchy of derivatives.
	Primary Risks Managed by Derivative Financial Instruments
	The main risks managed by derivative financial instruments are interest rate risk and foreign currency risk. The Company’s Board of Directors reviews and approves policies for managing each of these risks as summarized below.
	The Company enters into derivative transactions (principally interest rate swaps and forward foreign currency contracts) in order to manage interest rate and foreign currency risks arising from the Company’s operations and its sources of finance. The Company does not hold financial or derivative instruments for trading purposes.
	Interest Rate Risk — Investment Income
	As a result of the Company’s operating activities, the Company receives cash for premiums and claims which it deposits in short-term investments denominated in US dollars and other currencies. The Company earns interest on these funds, which is included in the Company’s financial statements as investment income. These funds are regulated in terms of access and the instruments in which they may be invested, most of which are short-term in maturity.
	In order to manage interest rate risk arising from these financial assets, the Company entered into interest rate swaps to receive a fixed rate of interest and pay a variable rate of interest denominated in the various currencies related to the short-term investments. The use of interest rate contracts essentially converted groups of short-term variable rate investments to fixed rate investments. The fair value of these contracts was recorded in other assets and other liabilities. For contracts that qualified as cash flow hedges for accounting purposes, the effective portions of changes in fair value were recorded as a component of other comprehensive income, to the extent that the hedge relationships were highly effective.
	From the fourth quarter of 2011, the Company stopped entering into any new hedging transactions relating to interest rate risk from investments, given the flat yield curve environment at that time. Further to this, during second quarter 2012, the Company closed out its legacy position for these interest rate swap contracts.
	The fair value of these swaps at the close out date was $16 million, representing a cash settlement amount on termination. In connection with the terminated swaps, the Company retained a gain of $15 million in other comprehensive income as the forecasted short-term investment transactions in relation to which the swaps qualified as cash flow hedges were still considered probable. These amounts are reclassified into earnings consistent with when the forecasted swap transactions affect earnings. We expect approximately $5 million of the gain to be recognized in the consolidated statement of operations in 2013 including $4 million already recognized in the nine months ended September 30, 2013.
	At September 30, 2013, the Company had no derivative financial instruments that were designated as cash flow hedges of interest rate risk on investments.
	Interest Rate Risk — Interest Expense
	The Company's operations are financed principally by $2,054 million fixed rate senior notes maturing through 2043 and $278 million under a 7-year term loan facility. The Company has access to $800 million under a revolving credit facility expiring July 23, 2018, and $22 million under two further revolving credit facilities.
	The 7-year term loan facility bears interest at LIBOR plus 1.50%. As of September 30, 2013, $nil was drawn on the $800 million revolving credit facility. Drawings under that facility bear interest at LIBOR plus 1.50%. These margins apply while the Company’s debt rating remains BBB-/Baa3. Should the Company’s debt rating change, then the margin will change in accordance with the credit facilities agreements. The fixed rate senior notes bear interest at various rates as detailed in Note 14 — ‘Debt’.
	During the three months ended March 31, 2010, the Company entered into a series of interest rate swaps for a total notional amount of $350 million to receive a fixed rate and pay a variable rate on a semi-annual basis, with a maturity date of July 15, 2015. The Company had previously designated these instruments as fair value hedges against its $350 million 5.625% senior notes due 2015 and accounted for them accordingly until the first quarter of 2013 at which point these swaps, although remaining as economic hedges, no longer qualified for hedge accounting.
	During the three months ended September 30, 2013, the Company closed out the above interest rate swaps and received a cash settlement of $13 million on termination.
	Following the partial extinguishment of the 5.625% senior notes due 2015 on August 15, 2013, we have recorded a credit of $7 million to remove a corresponding partial amount of the fair value adjustment to the carrying values of the notes originally recognized in connection with the interest rate swaps. The remaining $5 million fair value adjustment will be amortized through interest expense over the period to maturity.
	To hedge against the potential variability in benchmark interest rates in advance of the anticipated debt issuance, the Company entered into two short-term treasury locks during the three months ended June 30, 2013. These were closed out during the three months ended September 30, 2013 following the issue of the new senior notes described in Note 14 - 'Debt'. The fair value of these treasury locks at the close out date was $21 million, received as a cash settlement on termination.
	The Company had designated the Treasury locks as effective hedges of the anticipated transaction and had recognized a gain of $19 million in other comprehensive income in relation to the effective element that qualified for hedge accounting. This amount will be reclassified into earnings consistent with the recognition of interest expense on the 4.625% senior notes due 2023 and the 6.125% senior notes due 2043. In addition, the Company recognized a $2 million gain in interest expense for the portion of the treasury locks determined as ineffective.
	Foreign Currency Risk
	The Company’s primary foreign exchange risks arise:
	•	from changes in the exchange rate between US dollars and Pounds sterling as its London market operations earn the majority of their revenues in US dollars and incur expenses predominantly in Pounds sterling, and may also hold a significant net sterling asset or liability position on the balance sheet. In addition, the London market operations earn significant revenues in Euros and Japanese yen; and
	•	from the translation into US dollars of the net income and net assets of its foreign subsidiaries, excluding the London market operations which are US dollar denominated.
	The foreign exchange risks in its London market operations are hedged as follows:
	•	to the extent that forecast Pounds sterling expenses exceed Pounds sterling revenues, the Company limits its exposure to this exchange rate risk by the use of forward contracts matched to specific, clearly identified cash outflows arising in the ordinary course of business; and
	•	to the extent the UK operations earn significant revenues in Euros and Japanese yen, the Company limits its exposure to changes in the exchange rate between the US dollar and these currencies by the use of forward contracts matched to a percentage of forecast cash inflows in specific currencies and periods. In addition, we are also exposed to foreign exchange risk on any net sterling asset or liability position in our London market operations.
	The fair value of foreign currency contracts is recorded in other assets and other liabilities. For contracts that qualify as accounting hedges, changes in fair value resulting from movements in the spot exchange rate are recorded as a component of other comprehensive income while changes resulting from a movement in the time value are recorded in interest expense. For contracts that do not qualify for hedge accounting, the total change in fair value is recorded in interest expense. Amounts held in comprehensive income are reclassified into earnings when the hedged exposure affects earnings.
	At September 30, 2013 and December 31, 2012, the Company’s foreign currency contracts were all designated as hedging instruments except those relating to short-term cash flows and hedges of certain intercompany loans.
	The table below summarizes by major currency the contractual amounts of the Company’s forward contracts to exchange foreign currencies for Pounds sterling in the case of US dollars and US dollars for Euro and Japanese yen. Foreign currency notional amounts are reported in US dollars translated at contracted exchange rates.
		Sell				Fair value
		(millions)
	US dollar	$	240			$	14
	Euro	80				(2		)
	Japanese yen	39				3
	In addition to forward exchange contracts we undertake short-term foreign exchange swaps for liquidity purposes. These are not designated as hedges and do not qualify for hedge accounting. The fair values at September 30, 2013 and December 31, 2012 were immaterial.
	During the nine months ended September 30, 2013, the Company entered into a number of foreign currency transactions in order to hedge certain intercompany loans. These derivatives were not designated as hedging instruments and were for a total notional amount of $118 million (December 31, 2012: $63 million). In respect of these transactions, an immaterial amount has been recognized as an asset within other current assets and a nominal gain has been recognized in other operating expenses for the period.
	Derivative Financial Instruments
	The table below presents the fair value of the Company’s derivative financial instruments and their balance sheet classification at September 30, 2013 and December 31, 2012:
					Fair value
	Derivative financial instruments designated as hedging instruments:		Balance sheet		September 30,				31-Dec-12
			classification		2013
					(millions)
	Assets:
	Forward exchange contracts		Other assets		$	17			$	9
	Interest rate swaps (fair value hedges)		Other assets		—				22
	Total derivatives designated as hedging instruments				$	17			$	31
	Liabilities:
	Forward exchange contracts		Other liabilities		$	2			$	—
	Total derivatives designated as hedging instruments				$	2			$	—
	Cash Flow Hedges
	The table below presents the effects of derivative financial instruments in cash flow hedging relationships on the consolidated statements of operations and the consolidated statements of equity for the three and nine months ended September 30, 2013 and 2012:
	Derivatives in cash flow		Amount of				Location of gain (loss)		Amount of			Location of gain (loss)		Amount of
	hedging relationships		gain (loss)				reclassified from		gain (loss)			recognized in income on derivative		gain (loss)
			recognized				accumulated OCI(i) into		reclassified			(ineffective hedges and ineffective		recognized
			in OCI(i)on derivative (effective				income (effective element)		from			element of effective hedges)		in income on derivative
			element)						accumulated					(ineffective
									OCI(i) into					hedges
									income					and
									(effective					ineffective
									element)					element of
														effective
														hedges)
		(millions)						(millions)					(millions)
Three months ended September 30, 2013
Interest rate swaps		$	—			Investment income		$	(1	)	Other operating expenses		$	—
Treasury locks		3				Interest expense		—			Interest expense		1
Forward exchange contracts		21				Other operating expenses		—			Interest expense		—
Total		$	24					$	(1	)			$	1
Three months ended September 30, 2012
Interest rate swaps		$	—			Investment income		$	(2	)	Other operating expenses		$	—
Forward exchange contracts		—				Other operating expenses		—			Interest expense		—
Total		$	—					$	(2	)			$	—
Nine months ended September 30, 2013
Interest rate swaps		$	—			Investment income		$	(4	)	Other operating expenses		$	—
Treasury locks		19				Interest expense		—			Interest expense		2
Forward exchange contracts		7				Other operating expenses		(1		)	Interest expense		—
Total		$	26					$	(5	)			$	2
Nine months ended September 30, 2012
Interest rate swaps		$	3			Investment income		$	(5	)	Other operating expenses		$	—
Forward exchange contracts		7				Other operating expenses		—			Interest expense		—
Total		$	10					$	(5	)			$	—
____________________
Amounts above shown gross of tax.
(i) Other Comprehensive Income
For interest rate swaps, all components of each derivative’s gain or loss were included in the assessment of hedge effectiveness. For foreign exchange contracts, only the changes in fair value resulting from movements in the spot exchange rates are included in this assessment. In instances where the timing of expected cash flows can be matched exactly to the maturity of the foreign exchange contract, then changes in fair value attributable to movement in the forward points are also included.
At September 30, 2013, the Company estimates there will be $15 million of net derivative gains reclassified from accumulated comprehensive income into earnings within the next twelve months as the forecasted transactions affect earnings.
Fair Value Hedges
The Company had previously designated interest rate swaps as fair value hedges against its $350 million 5.625% senior notes due 2015 and accounted for them accordingly until the first quarter of 2013 at which point these swaps, although remaining as economic hedges, no longer qualified for hedge accounting.
The table below presents the effects of derivative financial instruments in fair value hedging relationships on the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.
Derivative in fair value hedging relationships		Hedged item in fair value hedging		(Loss) gain				Gain (loss) recognized for hedged item			Ineffectiveness recognized in interest expense
		relationship		recognized
				for
				derivative
				(millions)
Three months ended September 30, 2013
Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
Three months ended September 30, 2012
Interest rate swaps		5.625% senior notes due 2015		$	(1	)		$	—		$	1
Nine months ended September 30, 2013
Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
Nine months ended September 30, 2012
Interest rate swaps		5.625% senior notes due 2015		$	(1	)		$	(1	)	$	2
All components of each derivative’s gain or loss were included in the assessment of hedge effectiveness.
The table below presents the effects of derivative financial instruments no longer in fair value hedging relationships on the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.
Derivative no longer in fair value hedging relationships		Hedged item no longer in fair value hedging relationship		(Loss) gain				Amortization of prior loss recognized on hedged item			Net (loss) gain recognized (i)
				recognized
				for
				derivative
				(millions)
Three months ended September 30, 2013
Interest rate swaps		5.625% senior notes due 2015		$	(2	)		$	(9	)	$	(7	)
Three months ended September 30, 2012
Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
Nine months ended September 30, 2013
Interest rate swaps		5.625% senior notes due 2015		$	(5	)		$	(13	)	$	(8	)
Nine months ended September 30, 2012
Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
____________________
(i) the net loss was included entirely in interest expense, except for $7 million in the three and nine months ended September 30, 2013 which formed part of the loss on extinguishment of debt.
Credit Risk and Concentrations of Credit Risk
Credit risk represents the loss that would be recognized at the reporting date if counterparties failed to perform as contracted and from movements in interest rates and foreign exchange rates. The Company currently does not anticipate non-performance by its counterparties. The Company generally does not require collateral or other security to support financial instruments with credit risk.
Concentrations of credit risk that arise from financial instruments exist for groups of customers or counterparties when they have similar economic characteristics that would cause their ability to meet contractual obligations to be similarly affected by changes in economic or other conditions. Financial instruments on the balance sheet that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, accounts receivable and derivatives which are recorded at fair value.
The Company maintains a policy providing for the diversification of cash and cash equivalent investments and places such investments in an extensive number of financial institutions to limit the amount of credit risk exposure. These financial institutions are monitored on an ongoing basis for credit quality predominantly using information provided by credit agencies.
Concentrations of credit risk with respect to receivables are limited due to the large number of clients and markets in which the Company does business, as well as the dispersion across many geographic areas. Management does not believe significant risk exists in connection with the Company's concentrations of credit as of September 30, 2013.

FAIR_VALUE_MEASUREMENT

FAIR VALUE MEASUREMENT	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
FAIR VALUE MEASUREMENT	'
	FAIR VALUE MEASUREMENT
	The Company has categorized its assets and liabilities that are measured at fair value on a recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows:
	•	Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets;
	•	Level 2: refers to fair values estimated using observable market based inputs or unobservable inputs that are corroborated by market data; and
	•	Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data.
	The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments:
	•	Long-term debt excluding the fair value hedge - Fair values are based on quoted market values and so classified as Level 1 measurements.
	•	Derivative financial instruments - Market values have been used to determine the fair value of interest rate swaps and forward foreign exchange contracts based on estimated amounts the Company would receive or have to pay to terminate the agreements, taking into account the current interest rate environment or current foreign currency forward rates.
	Recurring basis
	The following table presents, for each of the fair value hierarchy levels, the Company's assets and liabilities that are measured at fair value on a recurring basis.
		30-Sep-13
		Quoted		Significant		Significant
		prices in		other		other
		active		observable		unobservable
		markets		inputs		inputs
		for
		identical
		assets
		Level 1		Level 2		Level 3		Total
		(millions)
	Assets at fair value:
	Cash and cash equivalents	$	623	$	—	$	—	$	623
	Fiduciary funds (included within Fiduciary assets)	2,099		—		—		2,099
	Derivative financial instruments	—		17		—		17
	Total assets	$	2,722	$	17	$	—	$	2,739
	Liabilities at fair value:
	Derivative financial instruments	—		2		—		2
	Total liabilities	$	—	$	2	$	—	$	2
		31-Dec-12
		Quoted		Significant		Significant
		prices in		other		other
		active		observable		unobservable
		markets		inputs		inputs
		for
		identical
		assets
		Level 1		Level 2		Level 3		Total
		(millions)
	Assets at fair value:
	Cash and cash equivalents	$	500	$	—	$	—	$	500
	Fiduciary funds (included within Fiduciary assets)	1,796		—		—		1,796
	Derivative financial instruments	—		31		—		31
	Total assets	$	2,296	$	31	$	—	$	2,327
	Liabilities at fair value:
	Changes in fair value of hedged debt (i)	$	—	$	18	$	—	$	18
	Total liabilities	$	—	$	18	$	—	$	18
	____________________
	(i)	Changes in the fair value of the underlying hedged debt instrument since inception of the hedging relationship are included in long-term debt.
	The estimated fair value of the Company’s financial instruments held or issued to finance the Company’s operations is summarized below. Certain estimates and judgments were required to develop the fair value amounts. The fair value amounts shown below are not necessarily indicative of the amounts that the Company would realize upon disposition nor do they indicate the Company’s intent or ability to dispose of the financial instrument.
		30-Sep-13				31-Dec-12
		Carrying		Fair		Carrying		Fair
		amount		value		amount		value
		(millions)
	Assets:
	Derivative financial instruments	$	17	$	17	$	31	$	31
	Liabilities:
	Short-term debt	$	17	$	17	$	15	$	15
	Long-term debt	2,315		2,440		2,338		2,576
	Derivative financial instruments	2		2		—		—

GOODWILL

GOODWILL	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
GOODWILL	'
	GOODWILL
	Goodwill represents the excess of the cost of businesses acquired over the fair market value of identifiable net assets at the dates of acquisition. Goodwill is not amortized but is subject to impairment testing annually and whenever facts or circumstances indicate that the carrying amounts may not be recoverable.
	The Company has determined that its reporting units are consistent with its operating segments: North America; International and Global. Goodwill is allocated to these reporting units based on the original purchase price allocation for acquisitions within the reporting units. When a business entity is sold, goodwill is allocated to the disposed entity based on the fair value of that entity compared with the fair value of the reporting unit in which it is included.
	The changes in the carrying amount of goodwill by segment for the nine months ended September 30, 2013 and the year ended December 31, 2012 are as follows:
		Global		North			International			Total
				America
		(millions)
	Balance at January 1, 2012
	Goodwill, gross	$	1,122	$	1,782		$	391		$	3,295
	Accumulated impairment losses	—		—			—			—
	Goodwill, net	$	1,122	$	1,782		$	391		$	3,295
	Purchase price allocation adjustments	—		—			2			2
	Goodwill acquired during the year	—		10			2			12
	Goodwill disposed of during the year	—		—			(1		)	(1		)
	Goodwill impairment charge	—		(492		)	—			(492		)
	Foreign exchange	5		—			6			11
	Balance at December 31, 2012
	Goodwill, gross	$	1,127	$	1,792		$	400		$	3,319
	Accumulated impairment losses	—		(492		)	—			(492		)
	Goodwill, net	$	1,127	$	1,300		$	400		$	2,827
	Goodwill acquired during the period	15		—			1			16
	Other movements (i)	—		(1		)	—			(1		)
	Foreign exchange	—		—			4			4
	Balance at September 30, 2013
	Goodwill, gross	$	1,142	$	1,791		$	405		$	3,338
	Accumulated impairment losses	—		(492		)	—			(492		)
	Goodwill, net	$	1,142	$	1,299		$	405		$	2,846
	________________________________
	(i)	North America — $(1) million (2012: $nil) tax benefit arising on the exercise of fully vested HRH stock options which were issued as part of the acquisition of HRH in 2008.

OTHER_INTANGIBLE_ASSETS_NET

OTHER INTANGIBLE ASSETS, NET	9 Months Ended
	Sep. 30, 2013
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'
OTHER INTANGIBLE ASSETS, NET	'
	OTHER INTANGIBLE ASSETS, NET
	Other intangible assets are classified into the following categories:
	•	‘Customer and Marketing Related’, including:
	•	client relationships;
	•	client lists;
	•	non-compete agreements;
	•	trade names; and
	•	‘Contract based, Technology and Other’ includes all other purchased intangible assets.
	The major classes of amortizable intangible assets are as follows:
		30-Sep-13							31-Dec-12
		Gross		Accumulated			Net		Gross		Accumulated			Net
		carrying		amortization			carrying		carrying		amortization			carrying
		amount					amount		amount					amount
		(millions)
	Customer and Marketing Related:
	Client Relationships	$	696	$	(344	)	$	352	$	717	$	(340	)	$	377
	Client Lists	3		(1		)	2		3		(1		)	2
	Non-compete Agreements	4		—			4		3		—			3
	Trade Names	2		(1		)	1		11		(10		)	1
	Total Customer and Marketing Related	705		(346		)	359		734		(351		)	383
	Contract based, Technology and Other	5		(3		)	2		4		(2		)	2
	Total amortizable intangible assets	$	710	$	(349	)	$	361	$	738	$	(353	)	$	385
	The aggregate amortization of intangible assets for the nine months ended September 30, 2013 was $42 million (nine months ended September 30, 2012: $44 million), of which $14 million was recognized in the three months ended September 30, 2013 (three months ended September 30, 2012: $14 million). The estimated aggregate amortization of intangible assets for each of the next five years ended December 31 is as follows:
		Remainder of		2014			2015		2016		2017			Thereafter		Total
		2013
		(millions)
	Amortization of intangible assets	$	14	$	49		$	41	$	36	$	32		$	189	$	361

OTHER_ASSETS

OTHER ASSETS	9 Months Ended
	Sep. 30, 2013
Other Assets [Abstract]	'
OTHER ASSETS	'
	OTHER ASSETS
	An analysis of other assets is as follows:
		September 30,		December 31,
		2013		2012
		(millions)
	Other current assets
	Prepayments and accrued income	$	82	$	61
	Income tax receivable	34		50
	Derivatives	9		14
	Debt issuance costs	3		3
	Deferred compensation plan assets	24		12
	Other	43		41
	Total other current assets	$	195	$	181
	Other non-current assets
	Deferred compensation plan assets	$	80	$	97
	Derivatives	8		17
	Prepayments and accrued income	18		24
	Debt issuance costs	16		12
	Other receivables	65		56
	Total other non-current assets	$	187	$	206
	Total other assets	$	382	$	387

OTHER_LIABILITIES

OTHER LIABILITIES	9 Months Ended
	Sep. 30, 2013
Other Liabilities [Abstract]	'
OTHER LIABILITIES	'
	OTHER LIABILITIES
	An analysis of other liabilities is as follows:
		September 30,		December 31,
		2013		2012
		(millions)
	Other current liabilities
	Accounts payable	$	134	$	88
	Accrued dividends payable	50		47
	Other taxes payable	51		44
	Accrued interest payable	7		34
	Derivatives	1		—
	Deferred compensation plan liability	24		12
	Other payables	114		102
	Total other current liabilities	$	381	$	327
	Other non-current liabilities
	Incentives from lessors	$	176	$	173
	Deferred compensation plan liability	80		101
	Capital lease obligation	24		28
	Other payables	73		73
	Total other non-current liabilities	$	353	$	375
	Total other liabilities	$	734	$	702

DEBT

DEBT	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
DEBT	'
	DEBT
	Short-term debt and current portion of the long-term debt consists of the following:
		September 30,		December 31,
		2013		2012
		(millions)
	Current portion of 7-year term loan facility expires 2018	$	15	$	15
	Revolving credit facility	2		—
		$	17	$	15
	Long-term debt consists of the following:
		September 30,		December 31,
		2013		2012
		(millions)
	7-year term loan facility expires 2018	$	263	$	274
	5.625% senior notes due 2015	148		350
	Fair value adjustment on 5.625% senior notes due 2015	5		18
	4.125% senior notes due 2016	299		299
	6.200% senior notes due 2017	394		600
	7.000% senior notes due 2019	187		300
	5.750% senior notes due 2021	496		496
	4.625% senior notes due 2023	249		—
	6.125% senior notes due 2043	273		—
	3-year term loan facility expires 2015	1		1
		$	2,315	$	2,338
	On July 23, 2013 we entered into an amendment to our existing credit facilities to extend both the amount of financing and the maturity date of the facilities. As a result of this amendment, our revolving credit facility was increased from $500 million to $800 million. The maturity date on the $300 million term loan was extended to July 23, 2018, from December 16, 2016. There has been no increase to the remaining $278 million outstanding on that loan.
	The 7-year term loan facility expiring 2018 bears interest at LIBOR plus 1.50% and is repayable in quarterly installments and a final repayment of $186 million is due in the third quarter of 2018. Drawings under the $800 million revolving credit facility bear interest at LIBOR plus 1.50% and the facility expires on July 23, 2018. These margins apply while the Company’s debt rating remains BBB-/Baa3. As of September 30, 2013 $nil was outstanding under this revolving credit facility.
	On August 15, 2013 the Company issued $250 million of 4.625% senior notes due 2023 and $275 million of 6.125% senior notes due 2043. The effective interest rates of these senior notes are 4.696% and 6.154%, respectively, which include the impact of the discount upon issuance.
	On July 25, 2013 the Company commenced an offer to purchase for cash any and all of its 5.625% senior notes due 2015 and a portion of its 6.200% senior notes due 2017 and its 7.000% senior notes due 2019 for an aggregate purchase price of up to $525 million. On August 22, 2013 the proceeds from the issue of the senior notes due 2023 and 2043 were used to fund the purchase of $202 million of 5.625% senior notes due 2015, $206 million of 6.200% senior notes due 2017 and $113 million of 7.000% senior notes due 2019.
	The Company incurred total losses on extinguishment of debt of $60 million during the three months ended September 30, 2013. This was made up of a tender premium of $65 million, the write-off of unamortized debt issuance costs of $2 million and a credit for the reduction of the fair value adjustment on 5.625% senior notes due 2015 of $7 million.

SUPPLEMENTAL_DISCLOSURES_OF_CA

SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information [Abstract]	'
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION	'
	SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
	Supplemental disclosures regarding cash flow information and non-cash investing and financing activities are as follows:
		Nine months ended September 30,
		2013			2012
		(millions)
	Supplemental disclosures of cash flow information:
	Cash payments for income taxes, net	$	36		$	43
	Cash payments for interest	115			117
	Supplemental disclosures of non-cash investing and financing income (expenses):
	Write-off of unamortized debt issuance costs	(2		)	—
	Write-back of fair value adjustment on 5.625% senior notes due 2015	7			—
	Acquisitions:
	Fair value of assets acquired, net of cash acquired	$	46		$	—
	Less: Fair value of liabilities assumed	(30		)	—
	Net assets acquired, net of cash acquired	$	16		$	—

COMPREHENSIVE_INCOME

COMPREHENSIVE INCOME	9 Months Ended
	Sep. 30, 2013
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]	'
Comprehensive Income (Loss) Note	'
	COMPREHENSIVE INCOME
	The components of comprehensive income are as follows:
		Three months ended September 30,
		2013												2012
		Before tax amount				Tax				Net of tax amount				Before tax amount				Tax			Net of tax amount
		(millions)
	Other comprehensive income:
	Foreign currency translation adjustments	$	82			$	—			$	82			$	35			$	—		$	35
	Pension funding adjustments:
	Foreign currency translation on pension funding adjustments	(51		)		14				(37		)		(19		)		5			(14		)
	Amortization of unrecognized actuarial loss	14				(3		)		11				11				(2		)	9
	Amortization of unrecognized prior service gain	(1		)		—				(1		)		(1		)		—			(1		)
		(38		)		11				(27		)		(9		)		3			(6		)
	Derivative instruments:
	Interest rate swap reclassification adjustment	(1		)		—				(1		)		(2		)		—			(2		)
	Gain on forward exchange contracts (effective element)	21				(4		)		17				—				—			—
	Gain on treasury lock (effective element)	3				(1		)		2				—				—			—
		23				(5		)		18				(2		)		—			(2		)
	Other comprehensive income	67				6				73				24				3			27
	Less: Other comprehensive income attributable to noncontrolling interests	(1		)		—				(1		)		—				—			—
	Other comprehensive income attributable to Willis Group Holdings	$	66			$	6			$	72			$	24			$	3		$	27
		Nine months ended September 30,
		2013												2012
		Before tax amount				Tax				Net of tax amount				Before tax amount				Tax			Net of tax amount
		(millions)
	Other comprehensive income:
	Foreign currency translation adjustments	$	(7	)		$	—			$	(7	)		$	21			$	—		$	21
	Pension funding adjustments:
	Foreign currency translation on pension funding adjustments	3				(1		)		2				(27		)		7			(20		)
	Amortization of unrecognized actuarial loss	41				(8		)		33				35				(9		)	26
	Amortization of unrecognized prior service gain	(4		)		1				(3		)		(4		)		1			(3		)
		40				(8		)		32				4				(1		)	3
	Derivative instruments:
	Gain on interest rate swaps (effective element)	—				—				—				3				(1		)	2
	Interest rate swap reclassification adjustment	(4		)		1				(3		)		(5		)		1			(4		)
	Gain on forward exchange contracts (effective element)	7				(1		)		6				7				(2		)	5
	Forward exchange contracts reclassification adjustment	(1		)		—				(1		)		—				—			—
	Gain on treasury lock (effective element)	19				(4		)		15				—				—			—
		21				(4		)		17				5				(2		)	3
	Other comprehensive income (loss)	54				(12		)		42				30				(3		)	27
	Less: Other comprehensive income attributable to noncontrolling interests	—				—				—				—				—			—
	Other comprehensive income (loss) attributable to Willis Group Holdings	$	54			$	(12	)		$	42			$	30			$	(3	)	$	27
	The components of accumulated other comprehensive loss, net of tax, are as follows:
			Net foreign currency translation adjustment				Pension funding adjustment				Net unrealized gain on derivative instruments				Total
			(millions)
	Balance at December 31, 2012		$	(34	)		$	(831	)		$	15			$	(850	)
	Other comprehensive income before reclassifications		(7		)		2				21				16
	Amounts reclassified from accumulated other comprehensive income		—				30				(4		)		26
	Net current-period other comprehensive income, net of tax and noncontrolling interests		(7		)		32				17				42
	Balance at September 30, 2013		$	(41	)		$	(799	)		$	32			$	(808	)
	Amounts reclassified out of accumulated other comprehensive income into the statement of operations are as follows:
	Details about accumulated other comprehensive income components		Amount reclassified from accumulated other comprehensive income								Affected line item in the statement of operations
			Three months ended September 30,
			2013				2012
			(millions)
	Gains and losses on cash flow hedges (Note 8)
	Interest rate swaps		$	(1	)		$	(2	)		Investment income
	Foreign exchange contracts		—				—				Other operating expenses
			(1		)		(2		)		Total before tax
	Tax		—				—
			$	(1	)		$	(2	)		Net of tax
	Amortization of defined benefit pension items (Note 6)
	Prior service gain		$	(1	)		$	(1	)		Salaries and benefits
Net actuarial loss		14				11				Salaries and benefits
		13				10				Total before tax
Tax		(3		)		(2		)
		$	10			$	8			Net of tax
Total reclassifications for the period		$	9			$	6
Details about accumulated other comprehensive income components		Amount reclassified from accumulated other comprehensive income								Affected line item in the statement of operations
		Nine months ended September 30,
		2013				2012
		(millions)
Gains and losses on cash flow hedges (Note 8)
Interest rate swaps		$	(4	)		$	(5	)		Investment income
Foreign exchange contracts		(1		)		—				Other operating expenses
		(5		)		(5		)		Total before tax
Tax		1				1
		$	(4	)		$	(4	)		Net of tax
Amortization of defined benefit pension items (Note 6)
Prior service gain		$	(4	)		$	(4	)		Salaries and benefits
Net actuarial loss		41				35				Salaries and benefits
		37				31				Total before tax
Tax		(7		)		(8		)
		$	30			$	23			Net of tax
Total reclassifications for the period		$	26			$	19

EQUITY_AND_NONCONTROLLING_INTE

EQUITY AND NONCONTROLLING INTERESTS	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity Note [Abstract]	'
EQUITY AND NONCONTROLLING INTERESTS	'
	EQUITY AND NONCONTROLLING INTERESTS
	The components of stockholders’ equity and noncontrolling interests are as follows:
		30-Sep-13									30-Sep-12
		Willis			Noncontrolling			Total			Willis			Noncontrolling			Total
		Group			interests			equity			Group			interests			equity
		Holdings									Holdings
		stockholders									stockholders
		(millions)
	Balance at beginning of period	$	1,699		$	26		$	1,725		$	2,486		$	31		$	2,517
	Comprehensive income:
	Net income	297			6			303			359			9			368
	Other comprehensive income, net of tax	42			—			42			27			—			27
	Comprehensive income	339			6			345			386			9			395
	Dividends	(147		)	(9		)	(156		)	(141		)	(11		)	(152		)
	Additional paid-in capital	137			—			137			64			—			64
	Repurchase of shares (i)	—			—			—			(100		)	—			(100		)
	Additional noncontrolling interests	—			—			—			2			1			3
	Purchase of subsidiary shares from noncontrolling interests	(4		)	—			(4		)	(23		)	(6		)	(29		)
	Balance at end of period	$	2,024		$	23		$	2,047		$	2,674		$	24		$	2,698
	_________________________________
	(i)	Based on settlement date we repurchased 2,796,546 shares at an average price of $35.87 in the nine months ended September 30, 2012.
	The effects on equity of changes in Willis Group Holdings ownership interest in its subsidiaries are as follows:
		30-Sep-13			30-Sep-12
		(millions)
	Net income attributable to Willis Group Holdings	$	297		$	359
	Transfers from noncontrolling interest:
	Decrease in Willis Group Holdings paid-in capital for purchase of noncontrolling interests	(4		)	(23		)
	Increase in Willis Group Holdings paid-in capital for sale of noncontrolling interests	—			2
	Net transfers to noncontrolling interests	(4		)	(21		)
	Change from net income attributable to Willis Group Holdings and transfers from noncontrolling interests	$	293		$	338

SEGMENT_INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
SEGMENT INFORMATION	'
	SEGMENT INFORMATION
	During the periods presented, the Company operated through three segments: Global, North America and International. Global provides specialist brokerage and consulting services to clients worldwide for specific industrial and commercial activities and is organized by specialism. North America and International predominantly comprise our retail operations which provide services to small, medium and large corporations, accessing Global’s specialist expertise when required.
	The Company evaluates the performance of its segments based on organic commissions and fees growth and operating income. For internal reporting and segmental reporting, the following items for which segmental management are not held accountable are excluded from segmental expenses:
	(i)	foreign exchange hedging activities, foreign exchange movements on the UK pension plan asset, foreign exchange gains and losses from currency purchases and sales, and foreign exchange movements on internal exposures;
	(ii)	amortization of intangible assets;
	(iii)	gains and losses on the disposal of operations;
	(iv)	significant legal and regulatory settlements which are managed centrally;
	(v)	write-off of uncollectible accounts receivable balance and associated legal fees and insurance recoveries arising in Chicago due to fraudulent overstatement of commissions and fees;
	(vi)	fees related to the extinguishment of debt; and
	(vii)	costs associated with the Expense Reduction Initiative.
	The accounting policies of the segments are consistent with those described in Note 2 — ‘Basis of Presentation and Significant Accounting Policies’ to the Company’s Annual Report on Form 10-K for the year ended December 31, 2012 and as amended by Current Report on Form 8-K subsequently filed on August 8, 2013.
	There are no inter-segment revenues, with segments operating on a revenue-sharing basis equivalent to that used when sharing business with other third-party brokers.
	Selected information regarding the Company’s segments is as follows:
		Three months ended September 30, 2013
		Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
		and fees			income			income			revenues			and		income			earnings of
														amortization					associates,
																			net of tax
		(millions)
	Global	$	250		$	1		$	—		$	251		$	7	$	36		$	—
	North America	328			1			—			329			9		57			—
	International	213			2			—			215			5		(9		)	(1		)
	Total Retail	541			3			—			544			14		48			(1		)
	Total Segments	791			4			—			795			21		84			(1		)
	Corporate and Other (i)	—			—			—			—			14		(9		)	—
	Total Consolidated	$	791		$	4		$	—		$	795		$	35	$	75		$	(1	)
		Three months ended September 30, 2012
		Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
		and fees			income			income			revenues			and		income			earnings of
														amortization					associates,
																			net of tax
		(millions)
	Global	$	235		$	—		$	—		$	235		$	7	$	52		$	—
	North America	315			2			1			318			7		53			—
	International	199			2			—			201			7		(9		)	(2		)
	Total Retail	514			4			1			519			14		44			(2		)
	Total Segments	749			4			1			754			21		96			(2		)
	Corporate and Other (i)	—			—			—			—			14		(26		)	—
	Total Consolidated	$	749		$	4		$	1		$	754		$	35	$	70		$	(2	)
	_________________________________
	(i)	See the following table for an analysis of the ‘Corporate and Other’ line.
		Three months ended September 30,
		2013			2012
		(millions)
	Amortization of intangible assets	$	(14	)	$	(14	)
	Net loss on disposal of operations (a)	—			(1		)
	India joint venture settlement (a)	—			(11		)
	Foreign exchange hedging	—			1
	Foreign exchange gain on the UK pension plan asset	4			—
	Fees related to the extinguishment of debt (b)	(1		)	—
	Other	2			(1		)
	Total Corporate and Other	$	(9	)	$	(26	)
	_________________________________
	(a)	$11 million settlement with former partners related to the termination of a joint venture arrangement in India. In addition, $1 million loss on disposal of operations was recorded related to the termination.
	(b)	$1 million of fees associated with the extinguishment of debt completed on August 15, 2013.
		Nine months ended September 30, 2013
		Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
		and fees			income			income			revenues			and		income			earnings of
														amortization					associates,
																			net of tax
		(millions)
	Global	$	938		$	3		$	—		$	941		$	21	$	313		$	—
	North America	1,024			2			3			1,029			27		203			—
International	760			6			—			766			15		104			11
Total Retail	1,784			8			3			1,795			42		307			11
Total Segments	2,722			11			3			2,736			63		620			11
Corporate and Other (i)	—			—			—			—			47		(87		)	—
Total Consolidated	$	2,722		$	11		$	3		$	2,736		$	110	$	533		$	11
	Nine months ended September 30, 2012
	Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
	and fees			income			income			revenues			and		income			earnings of
													amortization					associates,
																		net of tax
	(millions)
Global	$	887		$	3		$	—		$	890		$	20	$	325		$	—
North America	975			3			4			982			23		183			—
International	729			8			—			737			16		112			12
Total Retail	1,704			11			4			1,719			39		295			12
Total Segments	2,591			14			4			2,609			59		620			12
Corporate and Other (i)	—			—			—			—			44		(54		)	—
Total Consolidated	$	2,591		$	14		$	4		$	2,609		$	103	$	566		$	12
_________________________________
(i)	See the following table for an analysis of the ‘Corporate and Other’ line.
	Nine months ended September 30,
	2013			2012
	(millions)
Amortization of intangible assets	$	(42	)	$	(44	)
Net loss on disposal of operations (a)	—			(1		)
India joint venture settlement (a)	—			(11		)
Foreign exchange hedging	—			3
Foreign exchange gain on the UK pension plan asset	5			(1		)
Write-off of uncollectible accounts receivable balance in Chicago and associated legal fees (b)	—			(13		)
Expense reduction initiative (c)	(46		)	—
Insurance recovery (d)	—			5
Fees related to the extinguishment of debt (e)	(1		)	—
Other	(3		)	8
Total Corporate and Other	$	(87	)	$	(54	)
_________________________________
(a)	$11 million settlement with former partners related to the termination of a joint venture arrangement in India. In addition, $1 million loss on disposal of operations was recorded related to the termination.
(b)	Write-off of uncollectible accounts receivable balance in relation to a previously disclosed fraudulent overstatement of Commissions and fees.
(c)	Charge related to the assessment of the Company's organizational design.
(d)	Insurance recovery, recorded in Other operating expenses, related to a previously disclosed fraudulent activity in Chicago.
(e)	$1 million of fees associated with the extinguishment of debt completed on August 15, 2013.
The following table reconciles total consolidated operating income, as disclosed in the segment tables above, to consolidated loss or income before income taxes and interest in earnings of associates:
	Three months ended September 30,						Nine months ended September 30,
	2013			2012			2013			2012
	(millions)
Total consolidated operating income	$	75		$	70		$	533		$	566
Loss on extinguishment of debt	(60		)	—			(60		)	—
Interest expense	(30		)	(32		)	(93		)	(97		)
(Loss) income before income taxes and interest in earnings of associates	$	(15	)	$	38		$	380		$	469

FINANCIAL_INFORMATION_FOR_PARE

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES	9 Months Ended
	Sep. 30, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES	'
	FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
	Willis North America Inc. (‘Willis North America’) has $148 million senior notes outstanding that were issued on July 1, 2005, $394 million of senior notes issued on March 28, 2007 and $187 million of senior notes issued on September 29, 2009.
	All direct obligations under the senior notes were jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc and Willis Group Limited, collectively the ‘Other Guarantors’, and with Willis Group Holdings, the ‘Guarantor Companies’.
	The debt securities that were issued by Willis North America and guaranteed by the entities described above, and for which the disclosures set forth below relate and are required under applicable SEC rules, were issued under an effective registration statement.
	Presented below is condensed consolidating financial information for:
	(i)	Willis Group Holdings, which is a guarantor, on a parent company only basis;
	(ii)	the Other Guarantors, which are all 100 percent directly or indirectly owned subsidiaries of the parent and are all direct or indirect parents of the issuer;
	(iii)	the Issuer, Willis North America;
	(iv)	Other, which are the non-guarantor subsidiaries, on a combined basis;
	(v)	Consolidating adjustments; and
	(vi)	the Consolidated Company.
	The equity method has been used for investments in subsidiaries in the unaudited condensed consolidating balance sheets as of September 30, 2013 of Willis Group Holdings, the Other Guarantors and the Issuer. Investments in subsidiaries in the unaudited condensed consolidating balance sheet for Other represents the cost of investment in subsidiaries recorded in the parent companies of the non-guarantor subsidiaries.
	The entities included in the Other Guarantors column as of September 30, 2013 are Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc and Willis Group Limited.
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791
	Investment income	—			3			—			4			(3		)	4
	Other income	—			—			—			34			(34		)	—
	Total revenues	—			3			—			829			(37		)	795
	EXPENSES
	Salaries and benefits	—			—			(48		)	(493		)	—			(541		)
	Other operating expenses	3			(7		)	(43		)	(122		)	25			(144		)
	Depreciation expense	—			(1		)	(5		)	(15		)	—			(21		)
	Amortization of intangible assets	—			—			—			(16		)	2			(14		)
	Net loss on disposal of operations	—			—			—			(8		)	8			—
	Total expenses	3			(8		)	(96		)	(654		)	35			(720		)
	OPERATING INCOME (LOSS)	3			(5		)	(96		)	175			(2		)	75
	Investment income from Group undertakings	—			93			60			20			(173		)	—
	Loss on extinguishment of debt	—			—			(60		)	—			—			(60		)
	Interest expense	(11		)	(52		)	(31		)	(83		)	147			(30		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	36			(127		)	112			(28		)	(15		)
	Income taxes	—			2			—			(7		)	(6		)	(11		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	38			(127		)	105			(34		)	(26		)
	Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)
	Equity account for subsidiaries	(19		)	(58		)	62			—			15			—
	NET (LOSS) INCOME	(27		)	(20		)	(65		)	101			(16		)	(27		)
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(65	)	$	101		$	(16	)	$	(27	)
	Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	Comprehensive income (loss)	$	45		$	51		$	(62	)	$	155		$	(143	)	$	46
	Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)
	TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	(62	)	$	154		$	(143	)	$	45
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2012
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
	Investment income	—			2			—			4			(2		)	4
	Other income	—			—			—			1			—			1
	Total revenues	—			2			—			754			(2		)	754
EXPENSES
Salaries and benefits	—			—			(28		)	(474		)	—			(502		)
Other operating expenses	(1		)	(1		)	(8		)	(139		)	3			(146		)
Depreciation expense	—			—			(4		)	(17		)	—			(21		)
Amortization of intangible assets	—			—			—			(17		)	3			(14		)
Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
Total expenses	(1		)	(1		)	(40		)	(643		)	1			(684		)
OPERATING (LOSS) INCOME	(1		)	1			(40		)	111			(1		)	70
Investment income from Group undertakings	6			808			63			104			(981		)	—
Interest expense	(11		)	(61		)	(48		)	(68		)	156			(32		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	748			(25		)	147			(826		)	38
Income taxes	(6		)	—			9			(19		)	6			(10		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	748			(16		)	128			(820		)	28
Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(701		)	17			—			646			—
INCOME FROM CONTINUING OPERATIONS	26			47			1			123			(171		)	26
Discontinued operations, net of tax	—			—			—			—			—			—
NET INCOME	26			47			1			123			(171		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	1		$	123		$	(171	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	53		$	74		$	2		$	144		$	(220	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	2		$	144		$	(220	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			—			11			(9		)	11
Other income	—			—			—			(149		)	152			3
Total revenues	—			9			—			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	—			(93		)	(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(38		)	(128		)	(368		)	81			(455		)
Depreciation expense	—			(2		)	(16		)	(50		)	—			(68		)
Amortization of intangible assets	—			—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			—			(5		)	5			—
Total expenses	(3		)	(40		)	(237		)	(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(31		)	(237		)	569			235			533
Investment income from Group undertakings	—			265			195			68			(528		)	—
Loss on extinguishment of debt	—			—			(60		)	—			—			(60		)
Interest expense	(32		)	(151		)	(97		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	83			(199		)	381			150			380
Income taxes	—			8			—			(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	91			(199		)	287			148			292
Interest in earnings of associates, net of tax	—			—			—			4			7			11
Equity account for subsidiaries	332			237			184			—			(753		)	—
NET INCOME (LOSS)	297			328			(15		)	291			(598		)	303
Less: Net income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
NET INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	(15	)	$	285		$	(598	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income (loss)	$	339		$	369		$	(8	)	$	298		$	(653	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	(8	)	$	292		$	(653	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			—			14			(8		)	14
Other income	—			—			—			97			(93		)	4
Total revenues	—			8			—			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	—			(50		)	(1,457		)	—			(1,508		)
Other operating expenses	(8		)	1			(63		)	(367		)	6			(431		)
Depreciation expense	—			(1		)	(11		)	(47		)	—			(59		)
Amortization of intangible assets	—			—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			—			(19		)	18			(1		)
Total expenses	(9		)	—			(124		)	(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	8			(124		)	759			(68		)	566
Investment income from Group undertakings	6			994			193			118			(1,311		)	—
Interest expense	(32		)	(188		)	(122		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	814			(53		)	667			(924		)	469
Income taxes	1			3			19			(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	817			(34		)	531			(925		)	355
Interest in earnings of associates, net of tax	—			—			—			5			7			12
Equity account for subsidiaries	393			(416		)	70			—			(47		)	—
INCOME FROM CONTINUING OPERATIONS	359			401			36			536			(965		)	367
Discontinued operations, net of tax	—			—			—			1			—			1
NET INCOME	359			401			36			537			(965		)	368
Less: Net income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	36		$	528		$	(965	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	386		$	428		$	41		$	574		$	(1,034	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	41		$	565		$	(1,034	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
Accounts receivable, net	—			—			26			930			29			985
Fiduciary assets	—			—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			—			16			(3		)	14
Other current assets	1			93			11			287			(197		)	195
Total current assets	5			96			37			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	2,747			844			3,824			(6,228		)	—
Amounts owed by (to) Group undertakings	4,053			(3,361		)	(123		)	(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			13			56			404			(1		)	472
Goodwill	—			—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			—			523			(162		)	361
Investments in associates	—			—			—			(53		)	237			184
Deferred tax assets	—			—			—			29			(23		)	6
Pension benefits asset	—			—			—			253			—			253
Other non-current assets	4			151			7			167			(142		)	187
Total non-current assets	4			164			63			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			—			26			469			(9		)	489
Income taxes payable	—			50			—			132			(149		)	33
Short-term debt and current portion of long-term debt	—			15			—			2			—			17
Deferred tax liabilities	1			—			—			19			(2		)	18
Other current liabilities	52			8			20			327			(26		)	381
Total current liabilities	56			73			46			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			785			734			1			—			2,315
Liabilities for pension benefits	—			—			—			229			—			229
Deferred tax liabilities	—			—			—			59			(23		)	36
Provisions for liabilities	—			—			—			221			(13		)	208
Other non-current liabilities	—			—			47			307			(1		)	353
Total non-current liabilities	795			785			781			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	858		$	827		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	(6		)	5,872			(4,654		)	2,024
Noncontrolling interests	—			—			—			23			—			23
Total equity	2,024			(1,212		)	(6		)	5,895			(4,654		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			—			904			29			933
Fiduciary assets	—			—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			—			18			(6		)	13
Other current assets	1			65			38			241			(164		)	181
Total current assets	3			65			38			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	2,493			553			3,824			(5,328		)	—
Amounts owed by (to) Group undertakings	4,091			(3,959		)	687			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			11			63			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			134			41			157			(131		)	206
Total non-current assets	5			145			104			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			25			—			120			(126		)	19
Short-term debt and current portion of long-term debt	—			15			—			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			—			73			216			(22		)	327
Total current liabilities	63			40			73			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			274			1,268			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			5			7			363			—			375
Total non-current liabilities	795			279			1,275			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	319		$	1,348		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	34			5,248			(3,707		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	34			5,274			(3,707		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	103		$	(202	)	$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			2			7			—			9
Additions to fixed assets	—			(4		)	(11		)	(63		)	—			(78		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(4		)	(9		)	(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
Senior notes issued	—			522			—			—			—			522
Debt issuance costs	—			(8		)	—			—			—			(8		)
Repayments of debt	—			(11		)	(521		)	—			—			(532		)
Tender premium on extinguishment of senior notes	—			—			(65		)	—			—			(65		)
Proceeds from issue of shares	105			—			—			—			—			105
Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
Dividends paid	(144		)	—			—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			(599		)	797			(281		)	—			—
Net cash provided by (used in) financing activities	45			(96		)	211			(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	803		$	61		$	146		$	(657	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
Additions to fixed assets	—			(6		)	(13		)	(78		)	—			(97		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(6		)	(13		)	(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			20			—			—			—			20
Repayments of debt	—			(7		)	—			(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			—			41
Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
Dividends paid	(139		)	—			—			(657		)	657			(139		)
Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(810		)	(211		)	779			—			—
Net cash provided by (used in) financing activities	44			(797		)	(211		)	83			657			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			—			(163		)	149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			—			163			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424
FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
Trinity Acquisition plc has $525 million senior notes outstanding that were issued on August 15, 2013.
All direct obligations under the senior notes were jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V, Willis Investment UK Holdings Limited, TA I Limited, Willis Group Limited and Willis North America, Inc, collectively the 'Other Guarantors', and with Willis Group Holdings, the 'Guarantor Companies'.
The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by the Company and Willis North America (the ‘Willis North America Debt Securities’) in that Trinity Acquisition plc is the issuer and not a subsidiary guarantor, and Willis North America, Inc. is a subsidiary guarantor.
Presented below is condensed consolidating financial information for:
(i)	Willis Group Holdings, which is a guarantor, on a parent company only basis;
(ii)	the Other Guarantors, which are all 100 percent directly or indirectly owned subsidiaries of the parent. Willis Netherlands B.V, Willis Investment UK Holdings Limited and TA 1 Limited are all direct or indirect parents of the issuer and Willis Group Limited and Willis North America, Inc, are 100 percent direct or indirectly owned subsidiaries or the issuer;
(iii)	Trinity Acquisition plc, which is the issuer and is a 100 percent indirectly owned subsidiary of the parent;
(iv)	Other, which are the non-guarantor subsidiaries, on a combined basis;
(v)	Consolidating adjustments; and
(vi)	the Consolidated Company.
The equity method has been used for investments in subsidiaries in the condensed consolidating balance sheets as of September 30, 2013 of Willis Group Holdings, the Other Guarantors and the Issuer. Investments in subsidiaries in the condensed consolidating balance sheet for Other represents the cost of investment in subsidiaries recorded in the parent companies of the non-guarantor subsidiaries.
The entities included in the Other Guarantors column as of September 30, 2013 are Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, Willis North America, TA I Limited and Willis Group Limited.
Condensed Consolidating Statement of Operations
	Three months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791
Investment income	—			3			—			4			(3		)	4
Other income	—			—			—			34			(34		)	—
Total revenues	—			3			—			829			(37		)	795
EXPENSES
Salaries and benefits	—			(48		)	—			(493		)	—			(541		)
Other operating expenses	3			(50		)	—			(122		)	25			(144		)
Depreciation expense	—			(6		)	—			(15		)	—			(21		)
Amortization of intangible assets	—			—			—			(16		)	2			(14		)
Net loss on disposal of operations	—			—			—			(8		)	8			—
Total expenses	3			(104		)	—			(654		)	35			(720		)
OPERATING INCOME (LOSS)	3			(101		)	—			175			(2		)	75
Investment income from Group undertakings	—			137			16			20			(173		)	—
Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
Interest expense	(11		)	(71		)	(12		)	(83		)	147			(30		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(95		)	4			112			(28		)	(15		)
Income taxes	—			4			(2		)	(7		)	(6		)	(11		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(91		)	2			105			(34		)	(26		)
Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)
Equity account for subsidiaries	(19		)	71			(35		)	—			(17		)	—
NET (LOSS) INCOME	(27		)	(20		)	(33		)	101			(48		)	(27		)
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(33	)	$	101		$	(48	)	$	(27	)
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	45		$	51		$	31		$	155		$	(236	)	$	46
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	31		$	154		$	(236	)	$	45
Condensed Consolidating Statement of Operations
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
Investment income	—			2			—			4			(2		)	4
Other income	—			—			—			1			—			1
Total revenues	—			2			—			754			(2		)	754
EXPENSES
Salaries and benefits	—			(28		)	—			(474		)	—			(502		)
Other operating expenses	(1		)	(9		)	—			(139		)	3			(146		)
Depreciation expense	—			(4		)	—			(17		)	—			(21		)
Amortization of intangible assets	—			—			—			(17		)	3			(14		)
Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
Total expenses	(1		)	(41		)	—			(643		)	1			(684		)
OPERATING (LOSS) INCOME	(1		)	(39		)	—			111			(1		)	70
Investment income from Group undertakings	6			1,743			966			104			(2,819		)	—
Interest expense	(11		)	(100		)	(9		)	(68		)	156			(32		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	1,604			957			147			(2,664		)	38
Income taxes	(6		)	14			(5		)	(19		)	6			(10		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	1,618			952			128			(2,658		)	28
Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(1,571		)	(913		)	—			2,446			—
INCOME FROM CONTINUING OPERATIONS	26			47			39			123			(209		)	26
Discontinued operations, net of tax	—			—			—			—			—			—
NET INCOME	26			47			39			123			(209		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	39		$	123		$	(209	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	53		$	74		$	8		$	144		$	(226	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	8		$	144		$	(226	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			—			11			(9		)	11
Other income	—			—			—			(149		)	152			3
Total revenues	—			9			—			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	(93		)	—			(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(166		)	—			(368		)	81			(455		)
Depreciation expense	—			(18		)	—			(50		)	—			(68		)
Amortization of intangible assets	—			—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			—			(5		)	5			—
Total expenses	(3		)	(277		)	—			(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(268		)	—			569			235			533
Investment income from Group undertakings	—			415			45			68			(528		)	—
Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
Interest expense	(32		)	(219		)	(29		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(132		)	16			381			150			380
Income taxes	—			12			(4		)	(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(120		)	12			287			148			292
Interest in earnings of associates, net of tax	—			—			—			4			7			11
Equity account for subsidiaries	332			448			275			—			(1,055		)	—
NET INCOME	297			328			287			291			(900		)	303
Less: Net income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	287		$	285		$	(900	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	339		$	369		$	326		$	298		$	(987	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	326		$	292		$	(987	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			—			14			(8		)	14
Other income	—			—			—			97			(93		)	4
Total revenues	—			8			—			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	(50		)	—			(1,457		)	—			(1,508		)
Other operating expenses	(8		)	(63		)	1			(367		)	6			(431		)
Depreciation expense	—			(12		)	—			(47		)	—			(59		)
Amortization of intangible assets	—			—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			—			(19		)	18			(1		)
Total expenses	(9		)	(125		)	1			(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	(117		)	1			759			(68		)	566
Investment income from Group undertakings	6			2,191			1,284			118			(3,599		)	—
Interest expense	(32		)	(284		)	(26		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	1,790			1,259			667			(3,212		)	469
Income taxes	1			32			(10		)	(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	1,822			1,249			531			(3,213		)	355
Interest in earnings of associates, net of tax	—			—			—			5			7			12
Equity account for subsidiaries	393			(1,421		)	(877		)	—			1,905			—
INCOME FROM CONTINUING OPERATIONS	359			401			372			536			(1,301		)	367
Discontinued operations, net of tax	—			—			—			1			—			1
NET INCOME	359			401			372			537			(1,301		)	368
Less: Net income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	372		$	528		$	(1,301	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	386		$	428		$	342		$	574		$	(1,335	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	342		$	565		$	(1,335	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
Accounts receivable, net	—			26			—			930			29			985
Fiduciary assets	—			—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			—			16			(3		)	14
Other current assets	1			103			1			287			(197		)	195
Total current assets	5			132			1			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	3,066			3,398			3,824			(9,101		)	—
Amounts owed by (to) Group undertakings	4,053			(3,761		)	277			(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			69			—			404			(1		)	472
Goodwill	—			—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			—			523			(162		)	361
Investments in associates	—			—			—			(53		)	237			184
Deferred tax assets	—			—			—			29			(23		)	6
Pension benefits asset	—			—			—			253			—			253
Other non-current assets	4			148			10			167			(142		)	187
Total non-current assets	4			217			10			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			26			—			469			(9		)	489
Income taxes payable	—			35			15			132			(149		)	33
Short-term debt and current portion of long-term debt	—			—			15			2			—			17
Deferred tax liabilities	1			—			—			19			(2		)	18
Other current liabilities	52			24			4			327			(26		)	381
Total current liabilities	56			85			34			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			734			785			1			—			2,315
Liabilities for pension benefits	—			—			—			229			—			229
Deferred tax liabilities	—			—			—			59			(23		)	36
Provisions for liabilities	—			—			—			221			(13		)	208
Other non-current liabilities	—			47			—			307			(1		)	353
Total non-current liabilities	795			781			785			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	866		$	819		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	2,867			5,872			(7,527		)	2,024
Noncontrolling interests	—			—			—			23			—			23
Total equity	2,024			(1,212		)	2,867			5,895			(7,527		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			—			904			29			933
Fiduciary assets	—			—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			—			18			(6		)	13
Other current assets	1			102			1			241			(164		)	181
Total current assets	3			102			1			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	3,025			2,548			3,824			(7,855		)	—
Amounts owed by (to) Group undertakings	4,091			(3,581		)	309			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			74			—			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			172			3			157			(131		)	206
Total non-current assets	5			246			3			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			14			11			120			(126		)	19
Short-term debt and current portion of long-term debt	—			—			15			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			73			—			216			(22		)	327
Total current liabilities	63			87			26			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			1,268			274			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			12			—			363			—			375
Total non-current liabilities	795			1,280			274			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	1,367		$	300		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	2,561			5,248			(6,234		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	2,561			5,274			(6,234		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	(120	)	$	21		$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			2			—			7			—			9
Additions to fixed assets	—			(15		)	—			(63		)	—			(78		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(13		)	—			(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
Senior notes issued	—			—			522			—			—			522
Debt issuance costs	—			—			(8		)	—			—			(8		)
Repayments of debt	—			(521		)	(11		)	—			—			(532		)
Tender premium on extinguishment of debt	—			(65		)	—			—			—			(65		)
Proceeds from issue of shares	105			—			—			—			—			105
Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
Dividends paid	(144		)	—			—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			722			(524		)	(281		)	—			—
Net cash provided by (used in) financing activities	45			136			(21		)	(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	1,894		$	1,259		$	146		$	(2,946	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
Additions to fixed assets	—			(19		)	—			(78		)	—			(97		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(19		)	—			(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			20			—			—			20
Repayments of debt	—			—			(7		)	(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			—			41
Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
Dividends paid	(139		)	(1,220		)	(1,069		)	(657		)	2,946			(139		)
Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(818		)	(203		)	779			—			—
Net cash provided by (used in) financing activities	44			(2,038		)	(1,259		)	83			2,946			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			(163		)	—			149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			163			—			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424

FINANCIAL_INFORMATION_FOR_PARE1

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES	9 Months Ended
	Sep. 30, 2013
Financial Information for Parent Issuer Guarantor Subsidiaries and Non-Guarantor Subsidiaries Disclosure [Abstract]	'
FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES	'
	20	FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
	On March 17, 2011, the Company issued senior notes totaling $800 million in a registered public offering. These debt securities are issued by Willis Group Holdings (‘Holdings Debt Securities’) and are guaranteed by certain of the Company’s subsidiaries. Therefore, the Company is providing the unaudited condensed consolidating financial information below. The following 100 percent directly or indirectly owned subsidiaries fully and unconditionally guarantee the Holdings Debt Securities on a joint and several basis: Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited and Willis North America (the ‘Guarantors’).
	The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis North America (the ‘Willis North America Debt Securities’) (and for which unaudited condensed consolidating financial information is presented in Note 19) in that Willis Group Holdings is the Parent Issuer and Willis North America is a subsidiary guarantor.
	Presented below is condensed consolidating financial information for:
	(i)	Willis Group Holdings, which is the Parent Issuer;
	(ii)	the Guarantors, which are all 100 percent directly or indirectly owned subsidiaries of the parent;
	(iii)	Other, which are the non-guarantor subsidiaries, on a combined basis;
	(iv)	Consolidating adjustments; and
	(v)	the Consolidated Company.
	The equity method has been used for investments in subsidiaries in the unaudited condensed consolidating balance sheets as of September 30, 2013 of Willis Group Holdings and the Guarantors. Investments in subsidiaries in the unaudited condensed consolidating balance sheet for Other represents the cost of investment in subsidiaries recorded in the parent companies of the non-guarantor subsidiaries.
	The entities included in the Guarantors column as of September 30, 2013 are Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited and Willis North America.
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	791		$	—		$	791
	Investment income	—			3			4			(3		)	4
	Other income	—			—			34			(34		)	—
	Total revenues	—			3			829			(37		)	795
	EXPENSES
	Salaries and benefits	—			(48		)	(493		)	—			(541		)
	Other operating expenses	3			(50		)	(122		)	25			(144		)
	Depreciation expense	—			(6		)	(15		)	—			(21		)
	Amortization of intangible assets	—			—			(16		)	2			(14		)
	Net loss on disposal of operations	—			—			(8		)	8			—
	Total expenses	3			(104		)	(654		)	35			(720		)
	OPERATING INCOME (LOSS)	3			(101		)	175			(2		)	75
	Investment income from Group undertakings	—			153			20			(173		)	—
	Loss on extinguishment of debt	—			(60		)	—			—			(60		)
	Interest expense	(11		)	(83		)	(83		)	147			(30		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(91		)	112			(28		)	(15		)
	Income taxes	—			2			(7		)	(6		)	(11		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(89		)	105			(34		)	(26		)
	Interest in earnings of associates, net of tax	—			—			(4		)	3			(1		)
	Equity account for subsidiaries	(19		)	69			—			(50		)	—
	NET (LOSS) INCOME	(27		)	(20		)	101			(81		)	(27		)
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	101		$	(81	)	$	(27	)
	Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	Comprehensive income	$	45		$	51		$	155		$	(205	)	$	46
	Less: comprehensive income attributable to noncontrolling interests	—			—			(1		)	—			(1		)
	TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	154		$	(205	)	$	45
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2012
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	749		$	—		$	749
	Investment income	—			2			4			(2		)	4
	Other income	—			—			1			—			1
	Total revenues	—			2			754			(2		)	754
	EXPENSES
	Salaries and benefits	—			(28		)	(474		)	—			(502		)
Other operating expenses	(1		)	(9		)	(139		)	3			(146		)
Depreciation expense	—			(4		)	(17		)	—			(21		)
Amortization of intangible assets	—			—			(17		)	3			(14		)
Net gain on disposal of operations	—			—			4			(5		)	(1		)
Total expenses	(1		)	(41		)	(643		)	1			(684		)
OPERATING (LOSS) INCOME	(1		)	(39		)	111			(1		)	70
Investment income from Group undertakings	6			871			104			(981		)	—
Interest expense	(11		)	(109		)	(68		)	156			(32		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	723			147			(826		)	38
Income taxes	(6		)	9			(19		)	6			(10		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	732			128			(820		)	28
Interest in earnings of associates, net of tax	—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(685		)	—			647			—
INCOME FROM CONTINUING OPERATIONS	26			47			123			(170		)	26
NET INCOME	26			47			123			(170		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	123		$	(170	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
Comprehensive income	$	53		$	74		$	144		$	(218	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	144		$	(218	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			11			(9		)	11
Other income	—			—			(149		)	152			3
Total revenues	—			9			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	(93		)	(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(166		)	(368		)	81			(455		)
Depreciation expense	—			(18		)	(50		)	—			(68		)
Amortization of intangible assets	—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			(5		)	5			—
Total expenses	(3		)	(277		)	(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(268		)	569			235			533
Investment income from Group undertakings	—			460			68			(528		)	—
Loss on extinguishment of debt	—			(60		)	—			—			(60		)
Interest expense	(32		)	(248		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(116		)	381			150			380
Income taxes	—			8			(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(108		)	287			148			292
Interest in earnings of associates, net of tax	—			—			4			7			11
Equity account for subsidiaries	332			436			—			(768		)	—
NET INCOME	297			328			291			(613		)	303
Less: Net income attributable to noncontrolling interests	—			—			(6		)	—			(6		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	285		$	(613	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
Comprehensive income	$	339		$	369		$	298		$	(661	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	292		$	(661	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			14			(8		)	14
Other income	—			—			97			(93		)	4
Total revenues	—			8			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	(50		)	(1,457		)	—			(1,508		)
Other operating expenses	(8		)	(62		)	(367		)	6			(431		)
Depreciation expense	—			(12		)	(47		)	—			(59		)
Amortization of intangible assets	—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			(19		)	18			(1		)
Total expenses	(9		)	(124		)	(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	(116		)	759			(68		)	566
Investment income from Group undertakings	6			1,187			118			(1,311		)	—
Interest expense	(32		)	(310		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	761			667			(924		)	469
Income taxes	1			22			(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	783			531			(925		)	355
Interest in earnings of associates, net of tax	—			—			5			7			12
Equity account for subsidiaries	393			(382		)	—			(11		)	—
INCOME FROM CONTINUING OPERATIONS	359			401			536			(929		)	367
Discontinued operations, net of tax	—			—			1			—			1
NET INCOME	359			401			537			(929		)	368
Less: Net income attributable to noncontrolling interests	—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	528		$	(929	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
Comprehensive income	$	386		$	428		$	574		$	(993	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	565		$	(993	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Guarantors			Other			Consolidating			Consolidated
	Group									adjustments
	Holdings - the Parent Issuer
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	617		$	—		$	623
Accounts receivable, net	—			26			930			29			985
Fiduciary assets	—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			16			(3		)	14
Other current assets	1			104			287			(197		)	195
Total current assets	5			133			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	3,597			3,824			(6,234		)	—
Amounts owed by (to) Group undertakings	4,053			(3,484		)	(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			69			404			(1		)	472
Goodwill	—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			523			(162		)	361
Investments in associates	—			—			(53		)	237			184
Deferred tax assets	—			—			29			(23		)	6
Pension benefits asset	—			—			253			—			253
Other non-current assets	4			158			167			(142		)	187
Total non-current assets	4			227			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	473		$	17,784		$	(5,809	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			26			469			(9		)	489
Income taxes payable	—			50			132			(149		)	33
Short-term debt and current portion of long-term debt	—			15			2			—			17
Deferred tax liabilities	1			—			19			(2		)	18
Other current liabilities	52			28			327			(26		)	381
Total current liabilities	56			119			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			1,519			1			—			2,315
Liabilities for pension benefits	—			—			229			—			229
Deferred tax liabilities	—			—			59			(23		)	36
Provisions for liabilities	—			—			221			(13		)	208
Other non-current liabilities	—			47			307			(1		)	353
Total non-current liabilities	795			1,566			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	1,685		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	5,872			(4,660		)	2,024
Noncontrolling interests	—			—			23			—			23
Total equity	2,024			(1,212		)	5,895			(4,660		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	473		$	17,784		$	(5,809	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Guarantors			Other			Consolidating			Consolidated
	Group									adjustments
	Holdings - the Parent Issuer
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			904			29			933
Fiduciary assets	—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			18			(6		)	13
Other current assets	1			103			241			(164		)	181
Total current assets	3			103			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	3,012			3,824			(5,294		)	—
Amounts owed by (to) Group undertakings	4,091			(3,272		)	(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			74			395			(1		)	468
Goodwill	—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			484			(99		)	385
Investments in associates	—			—			(53		)	227			174
Deferred tax assets	—			—			42			(24		)	18
Pension benefits asset	—			—			136			—			136
Other non-current assets	5			175			157			(131		)	206
Total non-current assets	5			249			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	92		$	17,125		$	(4,662	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			543			(4		)	541
Income taxes payable	—			25			120			(126		)	19
Short-term debt and current portion of long-term debt	—			15			—			—			15
Deferred tax liabilities	1			—			25			(5		)	21
Other current liabilities	60			73			216			(22		)	327
Total current liabilities	63			113			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			1,542			1			—			2,338
Liabilities for pension benefits	—			—			282			—			282
Deferred tax liabilities	—			—			42			(24		)	18
Provisions for liabilities	—			—			188			(8		)	180
Other non-current liabilities	—			12			363			—			375
Total non-current liabilities	795			1,554			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	1,667		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	5,248			(3,673		)	1,699
Noncontrolling interests	—			—			26			—			26
Total equity	1,699			(1,575		)	5,274			(3,673		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	92		$	17,125		$	(4,662	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Guarantors			Other			Consolidating			Consolidated
	Group									adjustments
	Holdings - the Parent Issuer
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	(99	)	$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			2			7			—			9
Additions to fixed assets	—			(15		)	(63		)	—			(78		)
Additions to intangible assets	—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(13		)	(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			2			—			2
Senior notes issued	—			522			—			—			522
Debt issuance costs	—			(8		)	—			—			(8		)
Repayments of debt	—			(532		)	—			—			(532		)
Tender premium on extinguishment of debt	—			(65		)	—			—			(65		)
Proceeds from issue of shares	105			—			—			—			105
Excess tax benefits from share-based payment arrangement	1			—			—			—			1
Dividends paid	(144		)	—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			198			(281		)	—			—
Net cash provided by (used in) financing activities	45			115			(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Guarantors			Other			Consolidating			Consolidated
	Group									adjustments
	Holdings - the Parent Issuer
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	864		$	146		$	(657	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			8			—			8
Additions to fixed assets	—			(19		)	(78		)	—			(97		)
Additions to intangible assets	—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(19		)	(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			20			—			—			20
Repayments of debt	—			(7		)	(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			41
Excess tax benefits from share-based payment arrangement	—			—			2			—			2
Dividends paid	(139		)	—			(657		)	657			(139		)
Proceeds from sale of noncontrolling interests	—			—			3			—			3
Acquisition of noncontrolling interests	—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(1,021		)	779			—			—
Net cash provided by (used in) financing activities	44			(1,008		)	83			657			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			(163		)	149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			163			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	423		$	—		$	424

FINANCIAL_INFORMATION_FOR_ISSU

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Notes)	9 Months Ended
	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]	'
Financial Information for issuer, Parent guarantor, guarantor subsidiaries and non-guarantor subsidiaries [Text Block]	'
	FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
	Willis North America Inc. (‘Willis North America’) has $148 million senior notes outstanding that were issued on July 1, 2005, $394 million of senior notes issued on March 28, 2007 and $187 million of senior notes issued on September 29, 2009.
	All direct obligations under the senior notes were jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc and Willis Group Limited, collectively the ‘Other Guarantors’, and with Willis Group Holdings, the ‘Guarantor Companies’.
	The debt securities that were issued by Willis North America and guaranteed by the entities described above, and for which the disclosures set forth below relate and are required under applicable SEC rules, were issued under an effective registration statement.
	Presented below is condensed consolidating financial information for:
	(i)	Willis Group Holdings, which is a guarantor, on a parent company only basis;
	(ii)	the Other Guarantors, which are all 100 percent directly or indirectly owned subsidiaries of the parent and are all direct or indirect parents of the issuer;
	(iii)	the Issuer, Willis North America;
	(iv)	Other, which are the non-guarantor subsidiaries, on a combined basis;
	(v)	Consolidating adjustments; and
	(vi)	the Consolidated Company.
	The equity method has been used for investments in subsidiaries in the unaudited condensed consolidating balance sheets as of September 30, 2013 of Willis Group Holdings, the Other Guarantors and the Issuer. Investments in subsidiaries in the unaudited condensed consolidating balance sheet for Other represents the cost of investment in subsidiaries recorded in the parent companies of the non-guarantor subsidiaries.
	The entities included in the Other Guarantors column as of September 30, 2013 are Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, TA I Limited, Trinity Acquisition plc and Willis Group Limited.
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791
	Investment income	—			3			—			4			(3		)	4
	Other income	—			—			—			34			(34		)	—
	Total revenues	—			3			—			829			(37		)	795
	EXPENSES
	Salaries and benefits	—			—			(48		)	(493		)	—			(541		)
	Other operating expenses	3			(7		)	(43		)	(122		)	25			(144		)
	Depreciation expense	—			(1		)	(5		)	(15		)	—			(21		)
	Amortization of intangible assets	—			—			—			(16		)	2			(14		)
	Net loss on disposal of operations	—			—			—			(8		)	8			—
	Total expenses	3			(8		)	(96		)	(654		)	35			(720		)
	OPERATING INCOME (LOSS)	3			(5		)	(96		)	175			(2		)	75
	Investment income from Group undertakings	—			93			60			20			(173		)	—
	Loss on extinguishment of debt	—			—			(60		)	—			—			(60		)
	Interest expense	(11		)	(52		)	(31		)	(83		)	147			(30		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	36			(127		)	112			(28		)	(15		)
	Income taxes	—			2			—			(7		)	(6		)	(11		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	38			(127		)	105			(34		)	(26		)
	Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)
	Equity account for subsidiaries	(19		)	(58		)	62			—			15			—
	NET (LOSS) INCOME	(27		)	(20		)	(65		)	101			(16		)	(27		)
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(65	)	$	101		$	(16	)	$	(27	)
	Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	Comprehensive income (loss)	$	45		$	51		$	(62	)	$	155		$	(143	)	$	46
	Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)
	TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	(62	)	$	154		$	(143	)	$	45
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2012
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
	Investment income	—			2			—			4			(2		)	4
	Other income	—			—			—			1			—			1
	Total revenues	—			2			—			754			(2		)	754
EXPENSES
Salaries and benefits	—			—			(28		)	(474		)	—			(502		)
Other operating expenses	(1		)	(1		)	(8		)	(139		)	3			(146		)
Depreciation expense	—			—			(4		)	(17		)	—			(21		)
Amortization of intangible assets	—			—			—			(17		)	3			(14		)
Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
Total expenses	(1		)	(1		)	(40		)	(643		)	1			(684		)
OPERATING (LOSS) INCOME	(1		)	1			(40		)	111			(1		)	70
Investment income from Group undertakings	6			808			63			104			(981		)	—
Interest expense	(11		)	(61		)	(48		)	(68		)	156			(32		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	748			(25		)	147			(826		)	38
Income taxes	(6		)	—			9			(19		)	6			(10		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	748			(16		)	128			(820		)	28
Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(701		)	17			—			646			—
INCOME FROM CONTINUING OPERATIONS	26			47			1			123			(171		)	26
Discontinued operations, net of tax	—			—			—			—			—			—
NET INCOME	26			47			1			123			(171		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	1		$	123		$	(171	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	53		$	74		$	2		$	144		$	(220	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	2		$	144		$	(220	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			—			11			(9		)	11
Other income	—			—			—			(149		)	152			3
Total revenues	—			9			—			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	—			(93		)	(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(38		)	(128		)	(368		)	81			(455		)
Depreciation expense	—			(2		)	(16		)	(50		)	—			(68		)
Amortization of intangible assets	—			—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			—			(5		)	5			—
Total expenses	(3		)	(40		)	(237		)	(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(31		)	(237		)	569			235			533
Investment income from Group undertakings	—			265			195			68			(528		)	—
Loss on extinguishment of debt	—			—			(60		)	—			—			(60		)
Interest expense	(32		)	(151		)	(97		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	83			(199		)	381			150			380
Income taxes	—			8			—			(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	91			(199		)	287			148			292
Interest in earnings of associates, net of tax	—			—			—			4			7			11
Equity account for subsidiaries	332			237			184			—			(753		)	—
NET INCOME (LOSS)	297			328			(15		)	291			(598		)	303
Less: Net income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
NET INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	(15	)	$	285		$	(598	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income (loss)	$	339		$	369		$	(8	)	$	298		$	(653	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	(8	)	$	292		$	(653	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			—			14			(8		)	14
Other income	—			—			—			97			(93		)	4
Total revenues	—			8			—			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	—			(50		)	(1,457		)	—			(1,508		)
Other operating expenses	(8		)	1			(63		)	(367		)	6			(431		)
Depreciation expense	—			(1		)	(11		)	(47		)	—			(59		)
Amortization of intangible assets	—			—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			—			(19		)	18			(1		)
Total expenses	(9		)	—			(124		)	(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	8			(124		)	759			(68		)	566
Investment income from Group undertakings	6			994			193			118			(1,311		)	—
Interest expense	(32		)	(188		)	(122		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	814			(53		)	667			(924		)	469
Income taxes	1			3			19			(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	817			(34		)	531			(925		)	355
Interest in earnings of associates, net of tax	—			—			—			5			7			12
Equity account for subsidiaries	393			(416		)	70			—			(47		)	—
INCOME FROM CONTINUING OPERATIONS	359			401			36			536			(965		)	367
Discontinued operations, net of tax	—			—			—			1			—			1
NET INCOME	359			401			36			537			(965		)	368
Less: Net income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	36		$	528		$	(965	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	386		$	428		$	41		$	574		$	(1,034	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	41		$	565		$	(1,034	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
Accounts receivable, net	—			—			26			930			29			985
Fiduciary assets	—			—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			—			16			(3		)	14
Other current assets	1			93			11			287			(197		)	195
Total current assets	5			96			37			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	2,747			844			3,824			(6,228		)	—
Amounts owed by (to) Group undertakings	4,053			(3,361		)	(123		)	(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			13			56			404			(1		)	472
Goodwill	—			—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			—			523			(162		)	361
Investments in associates	—			—			—			(53		)	237			184
Deferred tax assets	—			—			—			29			(23		)	6
Pension benefits asset	—			—			—			253			—			253
Other non-current assets	4			151			7			167			(142		)	187
Total non-current assets	4			164			63			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			—			26			469			(9		)	489
Income taxes payable	—			50			—			132			(149		)	33
Short-term debt and current portion of long-term debt	—			15			—			2			—			17
Deferred tax liabilities	1			—			—			19			(2		)	18
Other current liabilities	52			8			20			327			(26		)	381
Total current liabilities	56			73			46			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			785			734			1			—			2,315
Liabilities for pension benefits	—			—			—			229			—			229
Deferred tax liabilities	—			—			—			59			(23		)	36
Provisions for liabilities	—			—			—			221			(13		)	208
Other non-current liabilities	—			—			47			307			(1		)	353
Total non-current liabilities	795			785			781			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	858		$	827		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	(6		)	5,872			(4,654		)	2,024
Noncontrolling interests	—			—			—			23			—			23
Total equity	2,024			(1,212		)	(6		)	5,895			(4,654		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			—			904			29			933
Fiduciary assets	—			—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			—			18			(6		)	13
Other current assets	1			65			38			241			(164		)	181
Total current assets	3			65			38			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	2,493			553			3,824			(5,328		)	—
Amounts owed by (to) Group undertakings	4,091			(3,959		)	687			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			11			63			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			134			41			157			(131		)	206
Total non-current assets	5			145			104			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			25			—			120			(126		)	19
Short-term debt and current portion of long-term debt	—			15			—			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			—			73			216			(22		)	327
Total current liabilities	63			40			73			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			274			1,268			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			5			7			363			—			375
Total non-current liabilities	795			279			1,275			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	319		$	1,348		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	34			5,248			(3,707		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	34			5,274			(3,707		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	103		$	(202	)	$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			2			7			—			9
Additions to fixed assets	—			(4		)	(11		)	(63		)	—			(78		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(4		)	(9		)	(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
Senior notes issued	—			522			—			—			—			522
Debt issuance costs	—			(8		)	—			—			—			(8		)
Repayments of debt	—			(11		)	(521		)	—			—			(532		)
Tender premium on extinguishment of senior notes	—			—			(65		)	—			—			(65		)
Proceeds from issue of shares	105			—			—			—			—			105
Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
Dividends paid	(144		)	—			—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			(599		)	797			(281		)	—			—
Net cash provided by (used in) financing activities	45			(96		)	211			(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	803		$	61		$	146		$	(657	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
Additions to fixed assets	—			(6		)	(13		)	(78		)	—			(97		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(6		)	(13		)	(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			20			—			—			—			20
Repayments of debt	—			(7		)	—			(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			—			41
Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
Dividends paid	(139		)	—			—			(657		)	657			(139		)
Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(810		)	(211		)	779			—			—
Net cash provided by (used in) financing activities	44			(797		)	(211		)	83			657			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			—			(163		)	149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			—			163			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424
FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES
Trinity Acquisition plc has $525 million senior notes outstanding that were issued on August 15, 2013.
All direct obligations under the senior notes were jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V, Willis Investment UK Holdings Limited, TA I Limited, Willis Group Limited and Willis North America, Inc, collectively the 'Other Guarantors', and with Willis Group Holdings, the 'Guarantor Companies'.
The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by the Company and Willis North America (the ‘Willis North America Debt Securities’) in that Trinity Acquisition plc is the issuer and not a subsidiary guarantor, and Willis North America, Inc. is a subsidiary guarantor.
Presented below is condensed consolidating financial information for:
(i)	Willis Group Holdings, which is a guarantor, on a parent company only basis;
(ii)	the Other Guarantors, which are all 100 percent directly or indirectly owned subsidiaries of the parent. Willis Netherlands B.V, Willis Investment UK Holdings Limited and TA 1 Limited are all direct or indirect parents of the issuer and Willis Group Limited and Willis North America, Inc, are 100 percent direct or indirectly owned subsidiaries or the issuer;
(iii)	Trinity Acquisition plc, which is the issuer and is a 100 percent indirectly owned subsidiary of the parent;
(iv)	Other, which are the non-guarantor subsidiaries, on a combined basis;
(v)	Consolidating adjustments; and
(vi)	the Consolidated Company.
The equity method has been used for investments in subsidiaries in the condensed consolidating balance sheets as of September 30, 2013 of Willis Group Holdings, the Other Guarantors and the Issuer. Investments in subsidiaries in the condensed consolidating balance sheet for Other represents the cost of investment in subsidiaries recorded in the parent companies of the non-guarantor subsidiaries.
The entities included in the Other Guarantors column as of September 30, 2013 are Willis Netherlands Holdings B.V., Willis Investment UK Holdings Limited, Willis North America, TA I Limited and Willis Group Limited.
Condensed Consolidating Statement of Operations
	Three months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791
Investment income	—			3			—			4			(3		)	4
Other income	—			—			—			34			(34		)	—
Total revenues	—			3			—			829			(37		)	795
EXPENSES
Salaries and benefits	—			(48		)	—			(493		)	—			(541		)
Other operating expenses	3			(50		)	—			(122		)	25			(144		)
Depreciation expense	—			(6		)	—			(15		)	—			(21		)
Amortization of intangible assets	—			—			—			(16		)	2			(14		)
Net loss on disposal of operations	—			—			—			(8		)	8			—
Total expenses	3			(104		)	—			(654		)	35			(720		)
OPERATING INCOME (LOSS)	3			(101		)	—			175			(2		)	75
Investment income from Group undertakings	—			137			16			20			(173		)	—
Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
Interest expense	(11		)	(71		)	(12		)	(83		)	147			(30		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(95		)	4			112			(28		)	(15		)
Income taxes	—			4			(2		)	(7		)	(6		)	(11		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(91		)	2			105			(34		)	(26		)
Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)
Equity account for subsidiaries	(19		)	71			(35		)	—			(17		)	—
NET (LOSS) INCOME	(27		)	(20		)	(33		)	101			(48		)	(27		)
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(33	)	$	101		$	(48	)	$	(27	)
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	45		$	51		$	31		$	155		$	(236	)	$	46
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	31		$	154		$	(236	)	$	45
Condensed Consolidating Statement of Operations
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
Investment income	—			2			—			4			(2		)	4
Other income	—			—			—			1			—			1
Total revenues	—			2			—			754			(2		)	754
EXPENSES
Salaries and benefits	—			(28		)	—			(474		)	—			(502		)
Other operating expenses	(1		)	(9		)	—			(139		)	3			(146		)
Depreciation expense	—			(4		)	—			(17		)	—			(21		)
Amortization of intangible assets	—			—			—			(17		)	3			(14		)
Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
Total expenses	(1		)	(41		)	—			(643		)	1			(684		)
OPERATING (LOSS) INCOME	(1		)	(39		)	—			111			(1		)	70
Investment income from Group undertakings	6			1,743			966			104			(2,819		)	—
Interest expense	(11		)	(100		)	(9		)	(68		)	156			(32		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	1,604			957			147			(2,664		)	38
Income taxes	(6		)	14			(5		)	(19		)	6			(10		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	1,618			952			128			(2,658		)	28
Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(1,571		)	(913		)	—			2,446			—
INCOME FROM CONTINUING OPERATIONS	26			47			39			123			(209		)	26
Discontinued operations, net of tax	—			—			—			—			—			—
NET INCOME	26			47			39			123			(209		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	39		$	123		$	(209	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	53		$	74		$	8		$	144		$	(226	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	8		$	144		$	(226	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			—			11			(9		)	11
Other income	—			—			—			(149		)	152			3
Total revenues	—			9			—			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	(93		)	—			(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(166		)	—			(368		)	81			(455		)
Depreciation expense	—			(18		)	—			(50		)	—			(68		)
Amortization of intangible assets	—			—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			—			(5		)	5			—
Total expenses	(3		)	(277		)	—			(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(268		)	—			569			235			533
Investment income from Group undertakings	—			415			45			68			(528		)	—
Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
Interest expense	(32		)	(219		)	(29		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(132		)	16			381			150			380
Income taxes	—			12			(4		)	(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(120		)	12			287			148			292
Interest in earnings of associates, net of tax	—			—			—			4			7			11
Equity account for subsidiaries	332			448			275			—			(1,055		)	—
NET INCOME	297			328			287			291			(900		)	303
Less: Net income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	287		$	285		$	(900	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	339		$	369		$	326		$	298		$	(987	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	326		$	292		$	(987	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			—			14			(8		)	14
Other income	—			—			—			97			(93		)	4
Total revenues	—			8			—			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	(50		)	—			(1,457		)	—			(1,508		)
Other operating expenses	(8		)	(63		)	1			(367		)	6			(431		)
Depreciation expense	—			(12		)	—			(47		)	—			(59		)
Amortization of intangible assets	—			—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			—			(19		)	18			(1		)
Total expenses	(9		)	(125		)	1			(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	(117		)	1			759			(68		)	566
Investment income from Group undertakings	6			2,191			1,284			118			(3,599		)	—
Interest expense	(32		)	(284		)	(26		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	1,790			1,259			667			(3,212		)	469
Income taxes	1			32			(10		)	(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	1,822			1,249			531			(3,213		)	355
Interest in earnings of associates, net of tax	—			—			—			5			7			12
Equity account for subsidiaries	393			(1,421		)	(877		)	—			1,905			—
INCOME FROM CONTINUING OPERATIONS	359			401			372			536			(1,301		)	367
Discontinued operations, net of tax	—			—			—			1			—			1
NET INCOME	359			401			372			537			(1,301		)	368
Less: Net income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	372		$	528		$	(1,301	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	386		$	428		$	342		$	574		$	(1,335	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	342		$	565		$	(1,335	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
Accounts receivable, net	—			26			—			930			29			985
Fiduciary assets	—			—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			—			16			(3		)	14
Other current assets	1			103			1			287			(197		)	195
Total current assets	5			132			1			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	3,066			3,398			3,824			(9,101		)	—
Amounts owed by (to) Group undertakings	4,053			(3,761		)	277			(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			69			—			404			(1		)	472
Goodwill	—			—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			—			523			(162		)	361
Investments in associates	—			—			—			(53		)	237			184
Deferred tax assets	—			—			—			29			(23		)	6
Pension benefits asset	—			—			—			253			—			253
Other non-current assets	4			148			10			167			(142		)	187
Total non-current assets	4			217			10			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			26			—			469			(9		)	489
Income taxes payable	—			35			15			132			(149		)	33
Short-term debt and current portion of long-term debt	—			—			15			2			—			17
Deferred tax liabilities	1			—			—			19			(2		)	18
Other current liabilities	52			24			4			327			(26		)	381
Total current liabilities	56			85			34			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			734			785			1			—			2,315
Liabilities for pension benefits	—			—			—			229			—			229
Deferred tax liabilities	—			—			—			59			(23		)	36
Provisions for liabilities	—			—			—			221			(13		)	208
Other non-current liabilities	—			47			—			307			(1		)	353
Total non-current liabilities	795			781			785			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	866		$	819		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	2,867			5,872			(7,527		)	2,024
Noncontrolling interests	—			—			—			23			—			23
Total equity	2,024			(1,212		)	2,867			5,895			(7,527		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			—			904			29			933
Fiduciary assets	—			—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			—			18			(6		)	13
Other current assets	1			102			1			241			(164		)	181
Total current assets	3			102			1			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	3,025			2,548			3,824			(7,855		)	—
Amounts owed by (to) Group undertakings	4,091			(3,581		)	309			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			74			—			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			172			3			157			(131		)	206
Total non-current assets	5			246			3			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			14			11			120			(126		)	19
Short-term debt and current portion of long-term debt	—			—			15			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			73			—			216			(22		)	327
Total current liabilities	63			87			26			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			1,268			274			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			12			—			363			—			375
Total non-current liabilities	795			1,280			274			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	1,367		$	300		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	2,561			5,248			(6,234		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	2,561			5,274			(6,234		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	(120	)	$	21		$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			2			—			7			—			9
Additions to fixed assets	—			(15		)	—			(63		)	—			(78		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(13		)	—			(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
Senior notes issued	—			—			522			—			—			522
Debt issuance costs	—			—			(8		)	—			—			(8		)
Repayments of debt	—			(521		)	(11		)	—			—			(532		)
Tender premium on extinguishment of debt	—			(65		)	—			—			—			(65		)
Proceeds from issue of shares	105			—			—			—			—			105
Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
Dividends paid	(144		)	—			—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			722			(524		)	(281		)	—			—
Net cash provided by (used in) financing activities	45			136			(21		)	(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	1,894		$	1,259		$	146		$	(2,946	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
Additions to fixed assets	—			(19		)	—			(78		)	—			(97		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(19		)	—			(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			20			—			—			20
Repayments of debt	—			—			(7		)	(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			—			41
Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
Dividends paid	(139		)	(1,220		)	(1,069		)	(657		)	2,946			(139		)
Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(818		)	(203		)	779			—			—
Net cash provided by (used in) financing activities	44			(2,038		)	(1,259		)	83			2,946			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			(163		)	—			149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			163			—			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424

INCOME_TAXES_Tables

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Components of Tax Charge	'
	The tables below reflect the components of the three and nine months ended September 30, 2013 and 2012 tax charge:
		Income			Tax			Effective tax
		before tax						rate
		(millions, except percentages)
	Three months ended September 30, 2013
	Non-US ordinary income taxed at estimated annual effective tax rate	$	45		$	(9	)	20	%
	US ordinary income and tax charge	(60		)	(4		)	(7	)%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	Benefit derived from the reduction in estimate of annual effective tax rate applied to ordinary income of the prior two quarters	—			1			—	%
	As reported	$	(15	)	$	(11	)	(73	)%
	Three months ended September 30, 2012
	Ordinary income taxed at estimated annual effective tax rate	$	39		$	(9	)	24	%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	Net adjustment in respect of prior periods	—			(3		)	—	%
	Non-tax deductible loss on disposal of operations	(1		)	—			—	%
	Benefit derived from the reduction in estimate of annual effective tax rate applied to ordinary income of the prior two quarters	—			1			—	%
	As reported	$	38		$	(10	)	26	%
		Income			Tax			Effective tax
		before tax						rate
		(millions, except percentages)
	Nine months ended September 30, 2013
	Non-US ordinary income taxed at estimated annual effective tax rate	$	386		$	(79	)	20	%
	US ordinary income and tax charge	(6		)	(10		)	(167	)%
	Items where tax effect is treated discretely:
	Impact of reduction in UK tax rate on deferred tax balances	$	—		$	1		—	%
	As reported	$	380		$	(88	)	23	%
	Nine months ended September 30, 2012
	Ordinary income taxed at estimated annual effective tax rate	$	482		$	(117	)	24	%
	Items where tax effect is treated discretely:
	Write-off of uncollectible accounts receivable balance in North America	(12		)	5			41	%
	Net adjustment is respect of prior periods	—			(3		)	—	%
	Non-tax deductible loss on disposal of operations	(1		)	—			—	%
	Impact of reduction in UK tax rate on deferred tax balances	—			1			—	%
	As reported	$	469		$	(114	)	24	%

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Basic and Diluted Earnings Per Share	'
	Basic and diluted earnings per share are as follows:
		Three months ended September 30,					Nine months ended September 30,
		2013			2012		2013			2012
		(millions, except per share data)
	Net (loss) income attributable to Willis Group Holdings	$	(27	)	$	26	$	297		$	359
	Basic average number of shares outstanding	177			173		175			173
	Dilutive effect of potentially issuable shares	—			2		3			3
	Diluted average number of shares outstanding	177			175		178			176
	Basic earnings per share:
	Continuing operations	$	(0.15	)	$	0.15	$	1.7		$	2.07
	Discontinued operations	—			—		—			0.01
	Net (loss) income attributable to Willis Group Holdings shareholders	$	(0.15	)	$	0.15	$	1.7		$	2.08
	Dilutive effect of potentially issuable shares	—			—		(0.03		)	(0.04		)
	Diluted earnings per share:
	Continuing operations	$	(0.15	)	$	0.15	$	1.67		$	2.03
	Discontinued operations	—			—		—			0.01
	Net (loss) income attributable to Willis Group Holdings shareholders	$	(0.15	)	$	0.15	$	1.67		$	2.04

PENSION_PLANS_Tables

PENSION PLANS (Tables)	9 Months Ended
	Sep. 30, 2013
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]	'
Components of Net Periodic Benefit (Income) Cost	'
	The components of the net periodic benefit (income) cost of the UK, US and international and US non-qualified defined benefit plans are as follows:
		Three months ended September 30,
		UK Pension						US Pension						International and US non-qualified Pension
		Benefits						Benefits						Benefits
		2013			2012			2013			2012			2013			2012
		(millions)
	Components of net periodic benefit (income) cost:
	Service cost	$	10		$	9		$	—		$	—		$	—		$	1
	Interest cost	26			27			10			11			2			1
	Expected return on plan assets	(47		)	(45		)	(13		)	(12		)	(2		)	(2		)
	Amortization of unrecognized prior service gain	(1		)	(1		)	—			—			—			—
	Amortization of unrecognized actuarial loss	11			9			3			2			—			—
	Net periodic benefit (income) cost	$	(1	)	$	(1	)	$	—		$	1		$	—		$	—
		Nine months ended September 30,
		UK Pension						US Pension						International and US non-qualified Pension
		Benefits						Benefits						Benefits
		2013			2012			2013			2012			2013			2012
		(millions)
	Components of net periodic benefit (income) cost:
	Service cost	$	28		$	26		$	—		$	—		$	2		$	3
	Interest cost	80			81			29			31			5			4
	Expected return on plan assets	(141		)	(135		)	(38		)	(35		)	(5		)	(5		)
	Amortization of unrecognized prior service gain	(4		)	(4		)	—			—			—			—
	Amortization of unrecognized actuarial loss	33			29			7			6			1			—
	Net periodic benefit (income) cost	$	(4	)	$	(3	)	$	(2	)	$	2		$	3		$	2

DERIVATIVE_FINANCIAL_INSTRUMEN1

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Summary of Contractual Amounts of Company's Forward Contracts by Major Currency	'
	The table below summarizes by major currency the contractual amounts of the Company’s forward contracts to exchange foreign currencies for Pounds sterling in the case of US dollars and US dollars for Euro and Japanese yen. Foreign currency notional amounts are reported in US dollars translated at contracted exchange rates.
		Sell				Fair value
		(millions)
	US dollar	$	240			$	14
	Euro	80				(2		)
	Japanese yen	39				3
Fair Value of Company's Derivative Financial Instruments and their Balance Sheet Classification	'
	The table below presents the fair value of the Company’s derivative financial instruments and their balance sheet classification at September 30, 2013 and December 31, 2012:
					Fair value
	Derivative financial instruments designated as hedging instruments:		Balance sheet		September 30,				31-Dec-12
			classification		2013
					(millions)
	Assets:
	Forward exchange contracts		Other assets		$	17			$	9
	Interest rate swaps (fair value hedges)		Other assets		—				22
	Total derivatives designated as hedging instruments				$	17			$	31
	Liabilities:
	Forward exchange contracts		Other liabilities		$	2			$	—
	Total derivatives designated as hedging instruments				$	2			$	—
Effects of Gains/(Losses) on Derivative Financial Instruments in Cash Flow Hedging Relationships on Consolidated Statements of Comprehensive Income and Consolidated Statements of Equity	'
	The table below presents the effects of derivative financial instruments in cash flow hedging relationships on the consolidated statements of operations and the consolidated statements of equity for the three and nine months ended September 30, 2013 and 2012:
	Derivatives in cash flow		Amount of				Location of gain (loss)		Amount of			Location of gain (loss)		Amount of
	hedging relationships		gain (loss)				reclassified from		gain (loss)			recognized in income on derivative		gain (loss)
			recognized				accumulated OCI(i) into		reclassified			(ineffective hedges and ineffective		recognized
			in OCI(i)on derivative (effective				income (effective element)		from			element of effective hedges)		in income on derivative
			element)						accumulated					(ineffective
									OCI(i) into					hedges
									income					and
									(effective					ineffective
									element)					element of
														effective
														hedges)
			(millions)						(millions)					(millions)
	Three months ended September 30, 2013
	Interest rate swaps		$	—			Investment income		$	(1	)	Other operating expenses		$	—
	Treasury locks		3				Interest expense		—			Interest expense		1
	Forward exchange contracts		21				Other operating expenses		—			Interest expense		—
	Total		$	24					$	(1	)			$	1
	Three months ended September 30, 2012
	Interest rate swaps		$	—			Investment income		$	(2	)	Other operating expenses		$	—
	Forward exchange contracts		—				Other operating expenses		—			Interest expense		—
	Total		$	—					$	(2	)			$	—
	Nine months ended September 30, 2013
	Interest rate swaps		$	—			Investment income		$	(4	)	Other operating expenses		$	—
	Treasury locks		19				Interest expense		—			Interest expense		2
	Forward exchange contracts		7				Other operating expenses		(1		)	Interest expense		—
	Total		$	26					$	(5	)			$	2
	Nine months ended September 30, 2012
	Interest rate swaps		$	3			Investment income		$	(5	)	Other operating expenses		$	—
	Forward exchange contracts		7				Other operating expenses		—			Interest expense		—
	Total		$	10					$	(5	)			$	—
	____________________
	Amounts above shown gross of tax.
	(i) Other Comprehensive Income
Effects of Derivative Financial Instruments in Fair Value Hedging Relationships on Consolidated Statements of Comprehensive Income	'
	The table below presents the effects of derivative financial instruments in fair value hedging relationships on the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.
	Derivative in fair value hedging relationships		Hedged item in fair value hedging		(Loss) gain				Gain (loss) recognized for hedged item			Ineffectiveness recognized in interest expense
			relationship		recognized
					for
					derivative
					(millions)
	Three months ended September 30, 2013
	Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
	Three months ended September 30, 2012
	Interest rate swaps		5.625% senior notes due 2015		$	(1	)		$	—		$	1
	Nine months ended September 30, 2013
	Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
	Nine months ended September 30, 2012
	Interest rate swaps		5.625% senior notes due 2015		$	(1	)		$	(1	)	$	2
	All components of each derivative’s gain or loss were included in the assessment of hedge effectiveness.
	The table below presents the effects of derivative financial instruments no longer in fair value hedging relationships on the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.
	Derivative no longer in fair value hedging relationships		Hedged item no longer in fair value hedging relationship		(Loss) gain				Amortization of prior loss recognized on hedged item			Net (loss) gain recognized (i)
					recognized
					for
					derivative
					(millions)
	Three months ended September 30, 2013
	Interest rate swaps		5.625% senior notes due 2015		$	(2	)		$	(9	)	$	(7	)
	Three months ended September 30, 2012
	Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
	Nine months ended September 30, 2013
	Interest rate swaps		5.625% senior notes due 2015		$	(5	)		$	(13	)	$	(8	)
	Nine months ended September 30, 2012
	Interest rate swaps		5.625% senior notes due 2015		$	—			$	—		$	—
	____________________
	(i) the net loss was included entirely in interest expense, except for $7 million in the three and nine months ended September 30, 2013 which formed part of the loss on extinguishment of debt.

FAIR_VALUE_MEASUREMENT_Tables

FAIR VALUE MEASUREMENT (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Assets and Liabilities Measured at Fair Value on Recurring Basis	'
		30-Sep-13
		Quoted		Significant		Significant
		prices in		other		other
		active		observable		unobservable
		markets		inputs		inputs
		for
		identical
		assets
		Level 1		Level 2		Level 3		Total
		(millions)
	Assets at fair value:
	Cash and cash equivalents	$	623	$	—	$	—	$	623
	Fiduciary funds (included within Fiduciary assets)	2,099		—		—		2,099
	Derivative financial instruments	—		17		—		17
	Total assets	$	2,722	$	17	$	—	$	2,739
	Liabilities at fair value:
	Derivative financial instruments	—		2		—		2
	Total liabilities	$	—	$	2	$	—	$	2
		31-Dec-12
		Quoted		Significant		Significant
		prices in		other		other
		active		observable		unobservable
		markets		inputs		inputs
		for
		identical
		assets
		Level 1		Level 2		Level 3		Total
		(millions)
	Assets at fair value:
	Cash and cash equivalents	$	500	$	—	$	—	$	500
	Fiduciary funds (included within Fiduciary assets)	1,796		—		—		1,796
	Derivative financial instruments	—		31		—		31
	Total assets	$	2,296	$	31	$	—	$	2,327
	Liabilities at fair value:
	Changes in fair value of hedged debt (i)	$	—	$	18	$	—	$	18
	Total liabilities	$	—	$	18	$	—	$	18
	____________________
	(i)	Changes in the fair value of the underlying hedged debt instrument since inception of the hedging relationship are included in long-term debt.
Summary of Estimated Fair Value of Company's Financial Instruments Held or Issued to Finance Company's Operations	'
	The estimated fair value of the Company’s financial instruments held or issued to finance the Company’s operations is summarized below. Certain estimates and judgments were required to develop the fair value amounts. The fair value amounts shown below are not necessarily indicative of the amounts that the Company would realize upon disposition nor do they indicate the Company’s intent or ability to dispose of the financial instrument.
		30-Sep-13				31-Dec-12
		Carrying		Fair		Carrying		Fair
		amount		value		amount		value
		(millions)
	Assets:
	Derivative financial instruments	$	17	$	17	$	31	$	31
	Liabilities:
	Short-term debt	$	17	$	17	$	15	$	15
	Long-term debt	2,315		2,440		2,338		2,576
	Derivative financial instruments	2		2		—		—

GOODWILL_Tables

GOODWILL (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Carrying Amount of Goodwill by Segment	'
	The changes in the carrying amount of goodwill by segment for the nine months ended September 30, 2013 and the year ended December 31, 2012 are as follows:
		Global		North			International			Total
				America
		(millions)
	Balance at January 1, 2012
	Goodwill, gross	$	1,122	$	1,782		$	391		$	3,295
	Accumulated impairment losses	—		—			—			—
	Goodwill, net	$	1,122	$	1,782		$	391		$	3,295
	Purchase price allocation adjustments	—		—			2			2
	Goodwill acquired during the year	—		10			2			12
	Goodwill disposed of during the year	—		—			(1		)	(1		)
	Goodwill impairment charge	—		(492		)	—			(492		)
	Foreign exchange	5		—			6			11
	Balance at December 31, 2012
	Goodwill, gross	$	1,127	$	1,792		$	400		$	3,319
	Accumulated impairment losses	—		(492		)	—			(492		)
	Goodwill, net	$	1,127	$	1,300		$	400		$	2,827
	Goodwill acquired during the period	15		—			1			16
	Other movements (i)	—		(1		)	—			(1		)
	Foreign exchange	—		—			4			4
	Balance at September 30, 2013
	Goodwill, gross	$	1,142	$	1,791		$	405		$	3,338
	Accumulated impairment losses	—		(492		)	—			(492		)
	Goodwill, net	$	1,142	$	1,299		$	405		$	2,846
	________________________________
	(i)	North America — $(1) million (2012: $nil) tax benefit arising on the exercise of fully vested HRH stock options which were issued as part of the acquisition of HRH in 2008.

OTHER_INTANGIBLE_ASSETS_NET_Ta

OTHER INTANGIBLE ASSETS, NET (Tables)	9 Months Ended
	Sep. 30, 2013
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'
Major Classes of Amortizable Intangible Assets	'
	The major classes of amortizable intangible assets are as follows:
		30-Sep-13							31-Dec-12
		Gross		Accumulated			Net		Gross		Accumulated			Net
		carrying		amortization			carrying		carrying		amortization			carrying
		amount					amount		amount					amount
		(millions)
	Customer and Marketing Related:
	Client Relationships	$	696	$	(344	)	$	352	$	717	$	(340	)	$	377
	Client Lists	3		(1		)	2		3		(1		)	2
	Non-compete Agreements	4		—			4		3		—			3
	Trade Names	2		(1		)	1		11		(10		)	1
	Total Customer and Marketing Related	705		(346		)	359		734		(351		)	383
	Contract based, Technology and Other	5		(3		)	2		4		(2		)	2
	Total amortizable intangible assets	$	710	$	(349	)	$	361	$	738	$	(353	)	$	385
Estimated Aggregate Amortization of Intangible Assets for Each of Next Five Years	'
	The estimated aggregate amortization of intangible assets for each of the next five years ended December 31 is as follows:
		Remainder of		2014			2015		2016		2017			Thereafter		Total
		2013
		(millions)
	Amortization of intangible assets	$	14	$	49		$	41	$	36	$	32		$	189	$	361

OTHER_ASSETS_Tables

OTHER ASSETS (Tables)	9 Months Ended
	Sep. 30, 2013
Other Assets [Abstract]	'
Analysis of Other Assets	'
	An analysis of other assets is as follows:
		September 30,		December 31,
		2013		2012
		(millions)
	Other current assets
	Prepayments and accrued income	$	82	$	61
	Income tax receivable	34		50
	Derivatives	9		14
	Debt issuance costs	3		3
	Deferred compensation plan assets	24		12
	Other	43		41
	Total other current assets	$	195	$	181
	Other non-current assets
	Deferred compensation plan assets	$	80	$	97
	Derivatives	8		17
	Prepayments and accrued income	18		24
	Debt issuance costs	16		12
	Other receivables	65		56
	Total other non-current assets	$	187	$	206
	Total other assets	$	382	$	387

OTHER_LIABILITIES_Tables

OTHER LIABILITIES (Tables)	9 Months Ended
	Sep. 30, 2013
Other Liabilities [Abstract]	'
Analysis of Other Liabilities	'
	An analysis of other liabilities is as follows:
		September 30,		December 31,
		2013		2012
		(millions)
	Other current liabilities
	Accounts payable	$	134	$	88
	Accrued dividends payable	50		47
	Other taxes payable	51		44
	Accrued interest payable	7		34
	Derivatives	1		—
	Deferred compensation plan liability	24		12
	Other payables	114		102
	Total other current liabilities	$	381	$	327
	Other non-current liabilities
	Incentives from lessors	$	176	$	173
	Deferred compensation plan liability	80		101
	Capital lease obligation	24		28
	Other payables	73		73
	Total other non-current liabilities	$	353	$	375
	Total other liabilities	$	734	$	702

DEBT_Tables

DEBT (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Short-Term Debt and Current Portion of Long-Term Debt	'
	Short-term debt and current portion of the long-term debt consists of the following:
		September 30,		December 31,
		2013		2012
		(millions)
	Current portion of 7-year term loan facility expires 2018	$	15	$	15
	Revolving credit facility	2		—
		$	17	$	15
Long-Term Debt	'
	Long-term debt consists of the following:
		September 30,		December 31,
		2013		2012
		(millions)
	7-year term loan facility expires 2018	$	263	$	274
	5.625% senior notes due 2015	148		350
	Fair value adjustment on 5.625% senior notes due 2015	5		18
	4.125% senior notes due 2016	299		299
	6.200% senior notes due 2017	394		600
	7.000% senior notes due 2019	187		300
	5.750% senior notes due 2021	496		496
	4.625% senior notes due 2023	249		—
	6.125% senior notes due 2043	273		—
	3-year term loan facility expires 2015	1		1
		$	2,315	$	2,338

SUPPLEMENTAL_DISCLOSURES_OF_CA1

SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information [Abstract]	'
Supplemental Disclosures Regarding Cash Flow Information and Non-Cash Flow Investing And Financing Activities	'
	Supplemental disclosures regarding cash flow information and non-cash investing and financing activities are as follows:
		Nine months ended September 30,
		2013			2012
		(millions)
	Supplemental disclosures of cash flow information:
	Cash payments for income taxes, net	$	36		$	43
	Cash payments for interest	115			117
	Supplemental disclosures of non-cash investing and financing income (expenses):
	Write-off of unamortized debt issuance costs	(2		)	—
	Write-back of fair value adjustment on 5.625% senior notes due 2015	7			—
	Acquisitions:
	Fair value of assets acquired, net of cash acquired	$	46		$	—
	Less: Fair value of liabilities assumed	(30		)	—
	Net assets acquired, net of cash acquired	$	16		$	—

COMPREHENSIVE_INCOME_Tables

COMPREHENSIVE INCOME (Tables)	9 Months Ended
	Sep. 30, 2013
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]	'
Components of Comprehensive Income	'
	The components of comprehensive income are as follows:
		Three months ended September 30,
		2013												2012
		Before tax amount				Tax				Net of tax amount				Before tax amount				Tax			Net of tax amount
		(millions)
	Other comprehensive income:
	Foreign currency translation adjustments	$	82			$	—			$	82			$	35			$	—		$	35
	Pension funding adjustments:
	Foreign currency translation on pension funding adjustments	(51		)		14				(37		)		(19		)		5			(14		)
	Amortization of unrecognized actuarial loss	14				(3		)		11				11				(2		)	9
	Amortization of unrecognized prior service gain	(1		)		—				(1		)		(1		)		—			(1		)
		(38		)		11				(27		)		(9		)		3			(6		)
	Derivative instruments:
	Interest rate swap reclassification adjustment	(1		)		—				(1		)		(2		)		—			(2		)
	Gain on forward exchange contracts (effective element)	21				(4		)		17				—				—			—
	Gain on treasury lock (effective element)	3				(1		)		2				—				—			—
		23				(5		)		18				(2		)		—			(2		)
	Other comprehensive income	67				6				73				24				3			27
	Less: Other comprehensive income attributable to noncontrolling interests	(1		)		—				(1		)		—				—			—
	Other comprehensive income attributable to Willis Group Holdings	$	66			$	6			$	72			$	24			$	3		$	27
		Nine months ended September 30,
		2013												2012
		Before tax amount				Tax				Net of tax amount				Before tax amount				Tax			Net of tax amount
		(millions)
	Other comprehensive income:
	Foreign currency translation adjustments	$	(7	)		$	—			$	(7	)		$	21			$	—		$	21
	Pension funding adjustments:
	Foreign currency translation on pension funding adjustments	3				(1		)		2				(27		)		7			(20		)
	Amortization of unrecognized actuarial loss	41				(8		)		33				35				(9		)	26
	Amortization of unrecognized prior service gain	(4		)		1				(3		)		(4		)		1			(3		)
		40				(8		)		32				4				(1		)	3
	Derivative instruments:
	Gain on interest rate swaps (effective element)	—				—				—				3				(1		)	2
	Interest rate swap reclassification adjustment	(4		)		1				(3		)		(5		)		1			(4		)
	Gain on forward exchange contracts (effective element)	7				(1		)		6				7				(2		)	5
	Forward exchange contracts reclassification adjustment	(1		)		—				(1		)		—				—			—
	Gain on treasury lock (effective element)	19				(4		)		15				—				—			—
		21				(4		)		17				5				(2		)	3
	Other comprehensive income (loss)	54				(12		)		42				30				(3		)	27
	Less: Other comprehensive income attributable to noncontrolling interests	—				—				—				—				—			—
	Other comprehensive income (loss) attributable to Willis Group Holdings	$	54			$	(12	)		$	42			$	30			$	(3	)	$	27
Components of Accumulated Other Comprehensive Loss, Net of Tax	'
	The components of accumulated other comprehensive loss, net of tax, are as follows:
			Net foreign currency translation adjustment				Pension funding adjustment				Net unrealized gain on derivative instruments				Total
			(millions)
	Balance at December 31, 2012		$	(34	)		$	(831	)		$	15			$	(850	)
	Other comprehensive income before reclassifications		(7		)		2				21				16
	Amounts reclassified from accumulated other comprehensive income		—				30				(4		)		26
	Net current-period other comprehensive income, net of tax and noncontrolling interests		(7		)		32				17				42
	Balance at September 30, 2013		$	(41	)		$	(799	)		$	32			$	(808	)
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	'
	Amounts reclassified out of accumulated other comprehensive income into the statement of operations are as follows:
	Details about accumulated other comprehensive income components		Amount reclassified from accumulated other comprehensive income								Affected line item in the statement of operations
			Three months ended September 30,
			2013				2012
			(millions)
	Gains and losses on cash flow hedges (Note 8)
	Interest rate swaps		$	(1	)		$	(2	)		Investment income
	Foreign exchange contracts		—				—				Other operating expenses
			(1		)		(2		)		Total before tax
	Tax		—				—
			$	(1	)		$	(2	)		Net of tax
	Amortization of defined benefit pension items (Note 6)
	Prior service gain		$	(1	)		$	(1	)		Salaries and benefits
	Net actuarial loss		14				11				Salaries and benefits
			13				10				Total before tax
	Tax		(3		)		(2		)
			$	10			$	8			Net of tax
	Total reclassifications for the period		$	9			$	6
	Details about accumulated other comprehensive income components		Amount reclassified from accumulated other comprehensive income								Affected line item in the statement of operations
			Nine months ended September 30,
			2013				2012
			(millions)
	Gains and losses on cash flow hedges (Note 8)
	Interest rate swaps		$	(4	)		$	(5	)		Investment income
	Foreign exchange contracts		(1		)		—				Other operating expenses
			(5		)		(5		)		Total before tax
	Tax		1				1
			$	(4	)		$	(4	)		Net of tax
	Amortization of defined benefit pension items (Note 6)
	Prior service gain		$	(4	)		$	(4	)		Salaries and benefits
	Net actuarial loss		41				35				Salaries and benefits
			37				31				Total before tax
	Tax		(7		)		(8		)
			$	30			$	23			Net of tax
	Total reclassifications for the period		$	26			$	19

EQUITY_AND_NONCONTROLLING_INTE1

EQUITY AND NONCONTROLLING INTERESTS (Tables)	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity Note [Abstract]	'
Equity and Noncontrolling Interests	'
	The components of stockholders’ equity and noncontrolling interests are as follows:
		30-Sep-13									30-Sep-12
		Willis			Noncontrolling			Total			Willis			Noncontrolling			Total
		Group			interests			equity			Group			interests			equity
		Holdings									Holdings
		stockholders									stockholders
		(millions)
	Balance at beginning of period	$	1,699		$	26		$	1,725		$	2,486		$	31		$	2,517
	Comprehensive income:
	Net income	297			6			303			359			9			368
	Other comprehensive income, net of tax	42			—			42			27			—			27
	Comprehensive income	339			6			345			386			9			395
	Dividends	(147		)	(9		)	(156		)	(141		)	(11		)	(152		)
	Additional paid-in capital	137			—			137			64			—			64
	Repurchase of shares (i)	—			—			—			(100		)	—			(100		)
	Additional noncontrolling interests	—			—			—			2			1			3
	Purchase of subsidiary shares from noncontrolling interests	(4		)	—			(4		)	(23		)	(6		)	(29		)
	Balance at end of period	$	2,024		$	23		$	2,047		$	2,674		$	24		$	2,698
	_________________________________
	(i)	Based on settlement date we repurchased 2,796,546 shares at an average price of $35.87 in the nine months ended September 30, 2012
Effects of Changes in Ownership Interest in Subsidiaries	'
	The effects on equity of changes in Willis Group Holdings ownership interest in its subsidiaries are as follows:
		30-Sep-13			30-Sep-12
		(millions)
	Net income attributable to Willis Group Holdings	$	297		$	359
	Transfers from noncontrolling interest:
	Decrease in Willis Group Holdings paid-in capital for purchase of noncontrolling interests	(4		)	(23		)
	Increase in Willis Group Holdings paid-in capital for sale of noncontrolling interests	—			2
	Net transfers to noncontrolling interests	(4		)	(21		)
	Change from net income attributable to Willis Group Holdings and transfers from noncontrolling interests	$	293		$	338

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	3 Months Ended																			9 Months Ended
	Sep. 30, 2013																			Sep. 30, 2013
Segment Reporting [Abstract]	'																			'
Information Regarding Company's Segments	'																			'
	Selected information regarding the Company’s segments is as follows:
																					Nine months ended September 30, 2013
																					Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
		Three months ended September 30, 2013																			and fees			income			income			revenues			and		income			earnings of
		Commissions			Investment			Other		Total		Depreciation		Operating			Interest in																amortization					associates,
		and fees			income			income		revenues		and		income			earnings of																					net of tax
												amortization					associates,				(millions)
																	net of tax			Global	$	938		$	3		$	—		$	941		$	21	$	313		$	—
		(millions)
	Global	$	250		$	1		$	—	$	251	$	7	$	36		$	—		North America	1,024			2			3			1,029			27		203			—
	North America	328			1			—		329		9		57			—			International	760			6			—			766			15		104			11
	International	213			2			—		215		5		(9		)	(1		)	Total Retail	1,784			8			3			1,795			42		307			11
	Total Retail	541			3			—		544		14		48			(1		)	Total Segments	2,722			11			3			2,736			63		620			11
	Total Segments	791			4			—		795		21		84			(1		)	Corporate and Other (i)	—			—			—			—			47		(87		)	—
	Corporate and Other (i)	—			—			—		—		14		(9		)	—			Total Consolidated	$	2,722		$	11		$	3		$	2,736		$	110	$	533		$	11
	Total Consolidated	$	791		$	4		$	—	$	795	$	35	$	75		$	(1	)
																					Nine months ended September 30, 2012
																					Commissions			Investment			Other			Total			Depreciation		Operating			Interest in
																					and fees			income			income			revenues			and		income			earnings of
		Three months ended September 30, 2012																															amortization					associates,
		Commissions			Investment			Other		Total		Depreciation		Operating			Interest in																					net of tax
		and fees			income			income		revenues		and		income			earnings of				(millions)
												amortization					associates,			Global	$	887		$	3		$	—		$	890		$	20	$	325		$	—
																	net of tax
		(millions)																		North America	975			3			4			982			23		183			—
	Global	$	235		$	—		$	—	$	235	$	7	$	52		$	—
																				International	729			8			—			737			16		112			12
	North America	315			2			1		318		7		53			—
																				Total Retail	1,704			11			4			1,719			39		295			12
	International	199			2			—		201		7		(9		)	(2		)
																				Total Segments	2,591			14			4			2,609			59		620			12
	Total Retail	514			4			1		519		14		44			(2		)
																				Corporate and Other (i)	—			—			—			—			44		(54		)	—
	Total Segments	749			4			1		754		21		96			(2		)
																				Total Consolidated	$	2,591		$	14		$	4		$	2,609		$	103	$	566		$	12
	Corporate and Other (i)	—			—			—		—		14		(26		)	—
																				_________________________________
	Total Consolidated	$	749		$	4		$	1	$	754	$	35	$	70		$	(2	)
																				(i)	See the following table for an analysis of the ‘Corporate and Other’ line.
	_________________________________
	(i)	See the following table for an analysis of the ‘Corporate and Other’ line.																			Nine months ended September 30,
																					2013			2012
																					(millions)
		Three months ended September 30,																		Amortization of intangible assets	$	(42	)	$	(44	)
		2013			2012															Net loss on disposal of operations (a)	—			(1		)
		(millions)
	Amortization of intangible assets	$	(14	)	$	(14	)													India joint venture settlement (a)	—			(11		)
	Net loss on disposal of operations (a)	—			(1		)
																				Foreign exchange hedging	—			3
	India joint venture settlement (a)	—			(11		)
																				Foreign exchange gain on the UK pension plan asset	5			(1		)
	Foreign exchange hedging	—			1
																				Write-off of uncollectible accounts receivable balance in Chicago and associated legal fees (b)	—			(13		)
	Foreign exchange gain on the UK pension plan asset	4			—
																				Expense reduction initiative (c)	(46		)	—
	Fees related to the extinguishment of debt (b)	(1		)	—
																				Insurance recovery (d)	—			5
	Other	2			(1		)
																				Fees related to the extinguishment of debt (e)	(1		)	—
	Total Corporate and Other	$	(9	)	$	(26	)
	_________________________________																			Other	(3		)	8
	(a)	$11 million settlement with former partners related to the termination of a joint venture arrangement in India. In addition, $1 million loss on disposal of operations was recorded related to the termination.																		Total Corporate and Other	$	(87	)	$	(54	)
																				_________________________________
(b)	$1 million of fees associated with the extinguishment of debt completed on August 15, 2013.
																			(a)	$11 million settlement with former partners related to the termination of a joint venture arrangement in India. In addition, $1 million loss on disposal of operations was recorded related to the termination.
																			(b)	Write-off of uncollectible accounts receivable balance in relation to a previously disclosed fraudulent overstatement of Commissions and fees.
																			(c)	Charge related to the assessment of the Company's organizational design.
																			(d)	Insurance recovery, recorded in Other operating expenses, related to a previously disclosed fraudulent activity in Chicago.
																			(e)	$1 million of fees associated with the extinguishment of debt completed on August 15, 2013.
Total Consolidated Operating Income	'																			'
																				The following table reconciles total consolidated operating income, as disclosed in the segment tables above, to consolidated loss or income before income taxes and interest in earnings of associates:
																					Three months ended September 30,						Nine months ended September 30,
																					2013			2012			2013			2012
																					(millions)
																				Total consolidated operating income	$	75		$	70		$	533		$	566
																				Loss on extinguishment of debt	(60		)	—			(60		)	—
																				Interest expense	(30		)	(32		)	(93		)	(97		)
																				(Loss) income before income taxes and interest in earnings of associates	$	(15	)	$	38		$	380		$	469

FINANCIAL_INFORMATION_FOR_PARE2

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Tables)	3 Months Ended																																						9 Months Ended
	Sep. 30, 2013																			Sep. 30, 2012																			Sep. 30, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'																			'																			'
Condensed Consolidating Statement of Operations	'																			'																			'
	Condensed Consolidating Statement of Operations																			Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013																			Three months ended September 30, 2012
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated				Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments							Group			Guarantors									adjustments
		Holdings																			Holdings
		(millions)																			(millions)
	REVENUES																			REVENUES
	Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791		Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
	Investment income	—			3			—			4			(3		)	4			Investment income	—			2			—			4			(2		)	4
	Other income	—			—			—			34			(34		)	—			Other income	—			—			—			1			—			1
	Total revenues	—			3			—			829			(37		)	795			Total revenues	—			2			—			754			(2		)	754
	EXPENSES																			EXPENSES
	Salaries and benefits	—			—			(48		)	(493		)	—			(541		)	Salaries and benefits	—			—			(28		)	(474		)	—			(502		)
	Other operating expenses	3			(7		)	(43		)	(122		)	25			(144		)	Other operating expenses	(1		)	(1		)	(8		)	(139		)	3			(146		)
	Depreciation expense	—			(1		)	(5		)	(15		)	—			(21		)	Depreciation expense	—			—			(4		)	(17		)	—			(21		)
	Amortization of intangible assets	—			—			—			(16		)	2			(14		)	Amortization of intangible assets	—			—			—			(17		)	3			(14		)
	Net loss on disposal of operations	—			—			—			(8		)	8			—			Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
	Total expenses	3			(8		)	(96		)	(654		)	35			(720		)	Total expenses	(1		)	(1		)	(40		)	(643		)	1			(684		)
	OPERATING INCOME (LOSS)	3			(5		)	(96		)	175			(2		)	75			OPERATING (LOSS) INCOME	(1		)	1			(40		)	111			(1		)	70
	Investment income from Group undertakings	—			93			60			20			(173		)	—			Investment income from Group undertakings	6			808			63			104			(981		)	—
	Loss on extinguishment of debt	—			—			(60		)	—			—			(60		)	Interest expense	(11		)	(61		)	(48		)	(68		)	156			(32		)
	Interest expense	(11		)	(52		)	(31		)	(83		)	147			(30		)	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	748			(25		)	147			(826		)	38
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	36			(127		)	112			(28		)	(15		)	Income taxes	(6		)	—			9			(19		)	6			(10		)
	Income taxes	—			2			—			(7		)	(6		)	(11		)	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	748			(16		)	128			(820		)	28
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	38			(127		)	105			(34		)	(26		)	Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
	Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)	Equity account for subsidiaries	38			(701		)	17			—			646			—
	Equity account for subsidiaries	(19		)	(58		)	62			—			15			—			INCOME FROM CONTINUING OPERATIONS	26			47			1			123			(171		)	26
	NET (LOSS) INCOME	(27		)	(20		)	(65		)	101			(16		)	(27		)	Discontinued operations, net of tax	—			—			—			—			—			—
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—			NET INCOME	26			47			1			123			(171		)	26
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(65	)	$	101		$	(16	)	$	(27	)	Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
																				NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	1		$	123		$	(171	)	$	26
Condensed Consolidating Statement of Comprehensive Income	'																			'																			'
	Condensed Consolidating Statement of Comprehensive Income																			Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013																			Three months ended September 30, 2012
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated				Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments							Group			Guarantors									adjustments
		Holdings																			Holdings
		(millions)																			(millions)
	Comprehensive income (loss)	$	45		$	51		$	(62	)	$	155		$	(143	)	$	46		Comprehensive income	$	53		$	74		$	2		$	144		$	(220	)	$	53
	Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)	Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
	TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	(62	)	$	154		$	(143	)	$	45		TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	2		$	144		$	(220	)	$	53
Condensed Consolidating Balance Sheet	'																			'																			'
																																							Condensed Consolidating Balance Sheet
																																								As of September 30, 2013
																																								Willis			The Other			The Issuer			Other			Consolidating			Consolidated
																																								Group			Guarantors									adjustments
																																								Holdings
																																								(millions)
																																							ASSETS
																																							CURRENT ASSETS
																																							Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
																																							Accounts receivable, net	—			—			26			930			29			985
																																							Fiduciary assets	—			—			—			10,123			(926		)	9,197
																																							Deferred tax assets	1			—			—			16			(3		)	14
																																							Other current assets	1			93			11			287			(197		)	195
																																							Total current assets	5			96			37			11,973			(1,097		)	11,014
																																							Investments in subsidiaries	(1,187		)	2,747			844			3,824			(6,228		)	—
																																							Amounts owed by (to) Group undertakings	4,053			(3,361		)	(123		)	(569		)	—			—
																																							NON-CURRENT ASSETS
																																							Fixed assets, net	—			13			56			404			(1		)	472
																																							Goodwill	—			—			—			1,233			1,613			2,846
																																							Other intangible assets, net	—			—			—			523			(162		)	361
																																							Investments in associates	—			—			—			(53		)	237			184
																																							Deferred tax assets	—			—			—			29			(23		)	6
																																							Pension benefits asset	—			—			—			253			—			253
																																							Other non-current assets	4			151			7			167			(142		)	187
																																							Total non-current assets	4			164			63			2,556			1,522			4,309
																																							TOTAL ASSETS	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
																																							LIABILITIES AND STOCKHOLDERS’ EQUITY
																																							CURRENT LIABILITIES
																																							Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
																																							Deferred revenue and accrued expenses	3			—			26			469			(9		)	489
																																							Income taxes payable	—			50			—			132			(149		)	33
																																							Short-term debt and current portion of long-term debt	—			15			—			2			—			17
																																							Deferred tax liabilities	1			—			—			19			(2		)	18
																																							Other current liabilities	52			8			20			327			(26		)	381
																																							Total current liabilities	56			73			46			11,072			(1,112		)	10,135
																																							NON-CURRENT LIABILITIES
																																							Long-term debt	795			785			734			1			—			2,315
																																							Liabilities for pension benefits	—			—			—			229			—			229
																																							Deferred tax liabilities	—			—			—			59			(23		)	36
																																							Provisions for liabilities	—			—			—			221			(13		)	208
																																							Other non-current liabilities	—			—			47			307			(1		)	353
																																							Total non-current liabilities	795			785			781			817			(37		)	3,141
																																							TOTAL LIABILITIES	$	851		$	858		$	827		$	11,889		$	(1,149	)	$	13,276
																																							EQUITY
																																							Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	(6		)	5,872			(4,654		)	2,024
																																							Noncontrolling interests	—			—			—			23			—			23
																																							Total equity	2,024			(1,212		)	(6		)	5,895			(4,654		)	2,047
																																							TOTAL LIABILITIES AND EQUITY	$	2,875		$	(354	)	$	821		$	17,784		$	(5,803	)	$	15,323
																																							Condensed Consolidating Balance Sheet
																																								As of December 31, 2012
																																								Willis			The Other			The Issuer			Other			Consolidating			Consolidated
																																								Group			Guarantors									adjustments
																																								Holdings
																																								(millions)
																																							ASSETS
																																							CURRENT ASSETS
																																							Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
																																							Accounts receivable, net	—			—			—			904			29			933
																																							Fiduciary assets	—			—			—			10,071			(800		)	9,271
																																							Deferred tax assets	1			—			—			18			(6		)	13
																																							Other current assets	1			65			38			241			(164		)	181
																																							Total current assets	3			65			38			11,733			(941		)	10,898
																																							Investments in subsidiaries	(1,542		)	2,493			553			3,824			(5,328		)	—
Amounts owed by (to) Group undertakings	4,091			(3,959		)	687			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			11			63			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			134			41			157			(131		)	206
Total non-current assets	5			145			104			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			25			—			120			(126		)	19
Short-term debt and current portion of long-term debt	—			15			—			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			—			73			216			(22		)	327
Total current liabilities	63			40			73			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			274			1,268			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			5			7			363			—			375
Total non-current liabilities	795			279			1,275			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	319		$	1,348		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	34			5,248			(3,707		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	34			5,274			(3,707		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(1,256	)	$	1,382		$	17,125		$	(4,696	)	$	15,112
Condensed Consolidating Statement of Cash Flows	'																			'																			'
																																							Condensed Consolidating Statement of Cash Flows
																																								Nine months ended September 30, 2013
																																								Willis			The Other			The Issuer			Other			Consolidating			Consolidated
																																								Group			Guarantors									adjustments
																																								Holdings
																																								(millions)
																																							NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	103		$	(202	)	$	508		$	—		$	366
																																							CASH FLOWS FROM INVESTING ACTIVITIES
																																							Proceeds on disposal of fixed and intangible assets	—			—			2			7			—			9
																																							Additions to fixed assets	—			(4		)	(11		)	(63		)	—			(78		)
																																							Additions to intangible assets	—			—			—			(1		)	—			(1		)
																																							Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
																																							Payments to acquire other investments	—			—			—			(5		)	—			(5		)
																																							Net cash used in investing activities	—			(4		)	(9		)	(92		)	—			(105		)
																																							CASH FLOWS FROM FINANCING ACTIVITIES
																																							Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
																																							Senior notes issued	—			522			—			—			—			522
																																							Debt issuance costs	—			(8		)	—			—			—			(8		)
																																							Repayments of debt	—			(11		)	(521		)	—			—			(532		)
																																							Tender premium on extinguishment of senior notes	—			—			(65		)	—			—			(65		)
																																							Proceeds from issue of shares	105			—			—			—			—			105
																																							Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
																																							Dividends paid	(144		)	—			—			—			—			(144		)
																																							Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
																																							Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
																																							Amounts owed by (to) Group undertakings	83			(599		)	797			(281		)	—			—
																																							Net cash provided by (used in) financing activities	45			(96		)	211			(292		)	—			(132		)
																																							INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
																																							Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
																																							CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
																																							CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
																																							Condensed Consolidating Statement of Cash Flows
																																								Nine months ended September 30, 2012
																																								Willis			The Other			The Issuer			Other			Consolidating			Consolidated
																																								Group			Guarantors									adjustments
																																								Holdings
																																								(millions)
																																							NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	803		$	61		$	146		$	(657	)	$	310
																																							CASH FLOWS FROM INVESTING ACTIVITIES
																																							Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
																																							Additions to fixed assets	—			(6		)	(13		)	(78		)	—			(97		)
																																							Additions to intangible assets	—			—			—			(1		)	—			(1		)
																																							Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
																																							Payments to acquire other investments	—			—			—			(5		)	—			(5		)
																																							Net cash used in investing activities	—			(6		)	(13		)	(80		)	—			(99		)
																																							CASH FLOWS FROM FINANCING ACTIVITIES
																																							Proceeds from draw down of revolving credit facility	—			20			—			—			—			20
																																							Repayments of debt	—			(7		)	—			(4		)	—			(11		)
																																							Repurchase of shares	(100		)	—			—			—			—			(100		)
																																							Proceeds from issue of shares	41			—			—			—			—			41
																																							Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
																																							Dividends paid	(139		)	—			—			(657		)	657			(139		)
																																							Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
																																							Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
																																							Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
																																							Amounts owed by (to) Group undertakings	242			(810		)	(211		)	779			—			—
																																							Net cash provided by (used in) financing activities	44			(797		)	(211		)	83			657			(224		)
																																							INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			—			(163		)	149			—			(13		)
																																							Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
																																							CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			—			163			273			—			436
																																							CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424

FINANCIAL_INFORMATION_FOR_PARE3

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Tables)	9 Months Ended
	Sep. 30, 2013
Financial Information for Parent Issuer Guarantor Subsidiaries and Non-Guarantor Subsidiaries Disclosure [Abstract]	'
Condensed Consolidated Statement of Comprehensive Income	'
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	791		$	—		$	791
	Investment income	—			3			4			(3		)	4
	Other income	—			—			34			(34		)	—
	Total revenues	—			3			829			(37		)	795
	EXPENSES
	Salaries and benefits	—			(48		)	(493		)	—			(541		)
	Other operating expenses	3			(50		)	(122		)	25			(144		)
	Depreciation expense	—			(6		)	(15		)	—			(21		)
	Amortization of intangible assets	—			—			(16		)	2			(14		)
	Net loss on disposal of operations	—			—			(8		)	8			—
	Total expenses	3			(104		)	(654		)	35			(720		)
	OPERATING INCOME (LOSS)	3			(101		)	175			(2		)	75
	Investment income from Group undertakings	—			153			20			(173		)	—
	Loss on extinguishment of debt	—			(60		)	—			—			(60		)
	Interest expense	(11		)	(83		)	(83		)	147			(30		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(91		)	112			(28		)	(15		)
	Income taxes	—			2			(7		)	(6		)	(11		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(89		)	105			(34		)	(26		)
	Interest in earnings of associates, net of tax	—			—			(4		)	3			(1		)
	Equity account for subsidiaries	(19		)	69			—			(50		)	—
	NET (LOSS) INCOME	(27		)	(20		)	101			(81		)	(27		)
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	101		$	(81	)	$	(27	)
	Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	Comprehensive income	$	45		$	51		$	155		$	(205	)	$	46
	Less: comprehensive income attributable to noncontrolling interests	—			—			(1		)	—			(1		)
	TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	154		$	(205	)	$	45
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2012
		Willis			The			Other			Consolidating			Consolidated
		Group			Guarantors						adjustments
		Holdings - the Parent Issuer
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	749		$	—		$	749
	Investment income	—			2			4			(2		)	4
	Other income	—			—			1			—			1
	Total revenues	—			2			754			(2		)	754
	EXPENSES
	Salaries and benefits	—			(28		)	(474		)	—			(502		)
	Other operating expenses	(1		)	(9		)	(139		)	3			(146		)
	Depreciation expense	—			(4		)	(17		)	—			(21		)
	Amortization of intangible assets	—			—			(17		)	3			(14		)
	Net gain on disposal of operations	—			—			4			(5		)	(1		)
	Total expenses	(1		)	(41		)	(643		)	1			(684		)
	OPERATING (LOSS) INCOME	(1		)	(39		)	111			(1		)	70
	Investment income from Group undertakings	6			871			104			(981		)	—
	Interest expense	(11		)	(109		)	(68		)	156			(32		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	723			147			(826		)	38
	Income taxes	(6		)	9			(19		)	6			(10		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	732			128			(820		)	28
Interest in earnings of associates, net of tax	—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(685		)	—			647			—
INCOME FROM CONTINUING OPERATIONS	26			47			123			(170		)	26
NET INCOME	26			47			123			(170		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	123		$	(170	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
Comprehensive income	$	53		$	74		$	144		$	(218	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	144		$	(218	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The			Other			Consolidating			Consolidated
	Group			Guarantors						adjustments
	Holdings - the Parent Issuer
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			11			(9		)	11
Other income	—			—			(149		)	152			3
Total revenues	—			9			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	(93		)	(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(166		)	(368		)	81			(455		)
Depreciation expense	—			(18		)	(50		)	—			(68		)
Amortization of intangible assets	—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			(5		)	5			—
Total expenses	(3		)	(277		)	(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(268		)	569			235			533
Investment income from Group undertakings	—			460			68			(528		)	—
Loss on extinguishment of debt	—			(60		)	—			—			(60		)
Interest expense	(32		)	(248		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(116		)	381			150			380
Income taxes	—			8			(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(108		)	287			148			292
Interest in earnings of associates, net of tax	—			—			4			7			11
Equity account for subsidiaries	332			436			—			(768		)	—
NET INCOME	297			328			291			(613		)	303
Less: Net income attributable to noncontrolling interests	—			—			(6		)	—			(6		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	285		$	(613	)	$	297
Condensed Consolidated Balance Sheet	'
	Condensed Consolidating Balance Sheet
		As of September 30, 2013
		Willis			The Guarantors			Other			Consolidating			Consolidated
		Group									adjustments
		Holdings - the Parent Issuer
		(millions)
	ASSETS
	CURRENT ASSETS
	Cash and cash equivalents	$	3		$	3		$	617		$	—		$	623
	Accounts receivable, net	—			26			930			29			985
	Fiduciary assets	—			—			10,123			(926		)	9,197
	Deferred tax assets	1			—			16			(3		)	14
	Other current assets	1			104			287			(197		)	195
	Total current assets	5			133			11,973			(1,097		)	11,014
	Investments in subsidiaries	(1,187		)	3,597			3,824			(6,234		)	—
	Amounts owed by (to) Group undertakings	4,053			(3,484		)	(569		)	—			—
	NON-CURRENT ASSETS
	Fixed assets, net	—			69			404			(1		)	472
	Goodwill	—			—			1,233			1,613			2,846
	Other intangible assets, net	—			—			523			(162		)	361
	Investments in associates	—			—			(53		)	237			184
	Deferred tax assets	—			—			29			(23		)	6
	Pension benefits asset	—			—			253			—			253
	Other non-current assets	4			158			167			(142		)	187
	Total non-current assets	4			227			2,556			1,522			4,309
	TOTAL ASSETS	$	2,875		$	473		$	17,784		$	(5,809	)	$	15,323
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	CURRENT LIABILITIES
	Fiduciary liabilities	$	—		$	—		$	10,123		$	(926	)	$	9,197
	Deferred revenue and accrued expenses	3			26			469			(9		)	489
	Income taxes payable	—			50			132			(149		)	33
	Short-term debt and current portion of long-term debt	—			15			2			—			17
	Deferred tax liabilities	1			—			19			(2		)	18
	Other current liabilities	52			28			327			(26		)	381
	Total current liabilities	56			119			11,072			(1,112		)	10,135
	NON-CURRENT LIABILITIES
	Long-term debt	795			1,519			1			—			2,315
	Liabilities for pension benefits	—			—			229			—			229
	Deferred tax liabilities	—			—			59			(23		)	36
	Provisions for liabilities	—			—			221			(13		)	208
	Other non-current liabilities	—			47			307			(1		)	353
	Total non-current liabilities	795			1,566			817			(37		)	3,141
	TOTAL LIABILITIES	$	851		$	1,685		$	11,889		$	(1,149	)	$	13,276
	EQUITY
	Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	5,872			(4,660		)	2,024
	Noncontrolling interests	—			—			23			—			23
	Total equity	2,024			(1,212		)	5,895			(4,660		)	2,047
	TOTAL LIABILITIES AND EQUITY	$	2,875		$	473		$	17,784		$	(5,809	)	$	15,323
	Condensed Consolidating Balance Sheet
		As of December 31, 2012
		Willis			The Guarantors			Other			Consolidating			Consolidated
		Group									adjustments
		Holdings - the Parent Issuer
		(millions)
	ASSETS
	CURRENT ASSETS
	Cash and cash equivalents	$	1		$	—		$	499		$	—		$	500
	Accounts receivable, net	—			—			904			29			933
	Fiduciary assets	—			—			10,071			(800		)	9,271
	Deferred tax assets	1			—			18			(6		)	13
	Other current assets	1			103			241			(164		)	181
	Total current assets	3			103			11,733			(941		)	10,898
	Investments in subsidiaries	(1,542		)	3,012			3,824			(5,294		)	—
Amounts owed by (to) Group undertakings	4,091			(3,272		)	(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			74			395			(1		)	468
Goodwill	—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			484			(99		)	385
Investments in associates	—			—			(53		)	227			174
Deferred tax assets	—			—			42			(24		)	18
Pension benefits asset	—			—			136			—			136
Other non-current assets	5			175			157			(131		)	206
Total non-current assets	5			249			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	92		$	17,125		$	(4,662	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			543			(4		)	541
Income taxes payable	—			25			120			(126		)	19
Short-term debt and current portion of long-term debt	—			15			—			—			15
Deferred tax liabilities	1			—			25			(5		)	21
Other current liabilities	60			73			216			(22		)	327
Total current liabilities	63			113			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			1,542			1			—			2,338
Liabilities for pension benefits	—			—			282			—			282
Deferred tax liabilities	—			—			42			(24		)	18
Provisions for liabilities	—			—			188			(8		)	180
Other non-current liabilities	—			12			363			—			375
Total non-current liabilities	795			1,554			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	1,667		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	5,248			(3,673		)	1,699
Noncontrolling interests	—			—			26			—			26
Total equity	1,699			(1,575		)	5,274			(3,673		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	92		$	17,125		$	(4,662	)	$	15,112
Condensed Consolidated Statement of Cash Flows	'
	Condensed Consolidating Statement of Cash Flows
		Nine months ended September 30, 2013
		Willis			The Guarantors			Other			Consolidating			Consolidated
		Group									adjustments
		Holdings - the Parent Issuer
		(millions)
	NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	(99	)	$	508		$	—		$	366
	CASH FLOWS FROM INVESTING ACTIVITIES
	Proceeds on disposal of fixed and intangible assets	—			2			7			—			9
	Additions to fixed assets	—			(15		)	(63		)	—			(78		)
	Additions to intangible assets	—			—			(1		)	—			(1		)
	Acquisitions of subsidiaries, net of cash acquired	—			—			(30		)	—			(30		)
	Payments to acquire other investments	—			—			(5		)	—			(5		)
	Net cash used in investing activities	—			(13		)	(92		)	—			(105		)
	CASH FLOWS FROM FINANCING ACTIVITIES
	Proceeds from draw down of revolving credit facility	—			—			2			—			2
	Senior notes issued	—			522			—			—			522
	Debt issuance costs	—			(8		)	—			—			(8		)
	Repayments of debt	—			(532		)	—			—			(532		)
	Tender premium on extinguishment of debt	—			(65		)	—			—			(65		)
	Proceeds from issue of shares	105			—			—			—			105
	Excess tax benefits from share-based payment arrangement	1			—			—			—			1
	Dividends paid	(144		)	—			—			—			(144		)
	Acquisition of noncontrolling interests	—			—			(4		)	—			(4		)
	Dividends paid to noncontrolling interests	—			—			(9		)	—			(9		)
	Amounts owed by (to) Group undertakings	83			198			(281		)	—			—
	Net cash provided by (used in) financing activities	45			115			(292		)	—			(132		)
	INCREASE IN CASH AND CASH EQUIVALENTS	2			3			124			—			129
	Effect of exchange rate changes on cash and cash equivalents	—			—			(6		)	—			(6		)
	CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			499			—			500
	CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	617		$	—		$	623
	Condensed Consolidating Statement of Cash Flows
		Nine months ended September 30, 2012
		Willis			The Guarantors			Other			Consolidating			Consolidated
		Group									adjustments
		Holdings - the Parent Issuer
		(millions)
	NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	864		$	146		$	(657	)	$	310
	CASH FLOWS FROM INVESTING ACTIVITIES
	Proceeds on disposal of fixed and intangible assets	—			—			8			—			8
	Additions to fixed assets	—			(19		)	(78		)	—			(97		)
	Additions to intangible assets	—			—			(1		)	—			(1		)
	Acquisitions of subsidiaries, net of cash acquired	—			—			(4		)	—			(4		)
	Payments to acquire other investments	—			—			(5		)	—			(5		)
	Net cash used in investing activities	—			(19		)	(80		)	—			(99		)
	CASH FLOWS FROM FINANCING ACTIVITIES
	Proceeds from draw down of revolving credit facility	—			20			—			—			20
	Repayments of debt	—			(7		)	(4		)	—			(11		)
	Repurchase of shares	(100		)	—			—			—			(100		)
	Proceeds from issue of shares	41			—			—			—			41
	Excess tax benefits from share-based payment arrangement	—			—			2			—			2
	Dividends paid	(139		)	—			(657		)	657			(139		)
	Proceeds from sale of noncontrolling interests	—			—			3			—			3
	Acquisition of noncontrolling interests	—			—			(29		)	—			(29		)
	Dividends paid to noncontrolling interests	—			—			(11		)	—			(11		)
	Amounts owed by (to) Group undertakings	242			(1,021		)	779			—			—
	Net cash provided by (used in) financing activities	44			(1,008		)	83			657			(224		)
	INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			(163		)	149			—			(13		)
	Effect of exchange rate changes on cash and cash equivalents	—			—			1			—			1
	CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			163			273			—			436
	CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	423		$	—		$	424

FINANCIAL_INFORMATION_FOR_ISSU1

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Tables)	9 Months Ended
	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]	'
Condensed Financial Statements [Text Block]	'
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	791		$	—		$	791
	Investment income	—			3			—			4			(3		)	4
	Other income	—			—			—			34			(34		)	—
	Total revenues	—			3			—			829			(37		)	795
	EXPENSES
	Salaries and benefits	—			(48		)	—			(493		)	—			(541		)
	Other operating expenses	3			(50		)	—			(122		)	25			(144		)
	Depreciation expense	—			(6		)	—			(15		)	—			(21		)
	Amortization of intangible assets	—			—			—			(16		)	2			(14		)
	Net loss on disposal of operations	—			—			—			(8		)	8			—
	Total expenses	3			(104		)	—			(654		)	35			(720		)
	OPERATING INCOME (LOSS)	3			(101		)	—			175			(2		)	75
	Investment income from Group undertakings	—			137			16			20			(173		)	—
	Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
	Interest expense	(11		)	(71		)	(12		)	(83		)	147			(30		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(95		)	4			112			(28		)	(15		)
	Income taxes	—			4			(2		)	(7		)	(6		)	(11		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(8		)	(91		)	2			105			(34		)	(26		)
	Interest in earnings of associates, net of tax	—			—			—			(4		)	3			(1		)
	Equity account for subsidiaries	(19		)	71			(35		)	—			(17		)	—
	NET (LOSS) INCOME	(27		)	(20		)	(33		)	101			(48		)	(27		)
	Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
	NET (LOSS) INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	(27	)	$	(20	)	$	(33	)	$	101		$	(48	)	$	(27	)
	Condensed Consolidating Statement of Comprehensive Income
		Three months ended September 30, 2013
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	Comprehensive income	$	45		$	51		$	31		$	155		$	(236	)	$	46
	Less: comprehensive income attributable to noncontrolling interests	—			—			—			(1		)	—			(1		)
	TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	45		$	51		$	31		$	154		$	(236	)	$	45
	Condensed Consolidating Statement of Operations
		Three months ended September 30, 2012
		Willis			The Other			The Issuer			Other			Consolidating			Consolidated
		Group			Guarantors									adjustments
		Holdings
		(millions)
	REVENUES
	Commissions and fees	$	—		$	—		$	—		$	749		$	—		$	749
	Investment income	—			2			—			4			(2		)	4
	Other income	—			—			—			1			—			1
	Total revenues	—			2			—			754			(2		)	754
	EXPENSES
	Salaries and benefits	—			(28		)	—			(474		)	—			(502		)
	Other operating expenses	(1		)	(9		)	—			(139		)	3			(146		)
	Depreciation expense	—			(4		)	—			(17		)	—			(21		)
	Amortization of intangible assets	—			—			—			(17		)	3			(14		)
	Net gain on disposal of operations	—			—			—			4			(5		)	(1		)
	Total expenses	(1		)	(41		)	—			(643		)	1			(684		)
	OPERATING (LOSS) INCOME	(1		)	(39		)	—			111			(1		)	70
	Investment income from Group undertakings	6			1,743			966			104			(2,819		)	—
	Interest expense	(11		)	(100		)	(9		)	(68		)	156			(32		)
	(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(6		)	1,604			957			147			(2,664		)	38
	Income taxes	(6		)	14			(5		)	(19		)	6			(10		)
	(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(12		)	1,618			952			128			(2,658		)	28
Interest in earnings of associates, net of tax	—			—			—			(5		)	3			(2		)
Equity account for subsidiaries	38			(1,571		)	(913		)	—			2,446			—
INCOME FROM CONTINUING OPERATIONS	26			47			39			123			(209		)	26
Discontinued operations, net of tax	—			—			—			—			—			—
NET INCOME	26			47			39			123			(209		)	26
Less: Net income attributable to noncontrolling interests	—			—			—			—			—			—
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	26		$	47		$	39		$	123		$	(209	)	$	26
Condensed Consolidating Statement of Comprehensive Income
	Three months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	53		$	74		$	8		$	144		$	(226	)	$	53
Less: comprehensive income attributable to noncontrolling interests	—			—			—			—			—			—
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	53		$	74		$	8		$	144		$	(226	)	$	53
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,722		$	—		$	2,722
Investment income	—			9			—			11			(9		)	11
Other income	—			—			—			(149		)	152			3
Total revenues	—			9			—			2,584			143			2,736
EXPENSES
Salaries and benefits	(1		)	(93		)	—			(1,544		)	—			(1,638		)
Other operating expenses	(2		)	(166		)	—			(368		)	81			(455		)
Depreciation expense	—			(18		)	—			(50		)	—			(68		)
Amortization of intangible assets	—			—			—			(48		)	6			(42		)
Net loss on disposal of operations	—			—			—			(5		)	5			—
Total expenses	(3		)	(277		)	—			(2,015		)	92			(2,203		)
OPERATING (LOSS) INCOME	(3		)	(268		)	—			569			235			533
Investment income from Group undertakings	—			415			45			68			(528		)	—
Loss on extinguishment of debt	—			(60		)	—			—			—			(60		)
Interest expense	(32		)	(219		)	(29		)	(256		)	443			(93		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(132		)	16			381			150			380
Income taxes	—			12			(4		)	(94		)	(2		)	(88		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(35		)	(120		)	12			287			148			292
Interest in earnings of associates, net of tax	—			—			—			4			7			11
Equity account for subsidiaries	332			448			275			—			(1,055		)	—
NET INCOME	297			328			287			291			(900		)	303
Less: Net income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	297		$	328		$	287		$	285		$	(900	)	$	297
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	339		$	369		$	326		$	298		$	(987	)	$	345
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(6		)	—			(6		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	339		$	369		$	326		$	292		$	(987	)	$	339
Condensed Consolidating Statement of Operations
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
REVENUES
Commissions and fees	$	—		$	—		$	—		$	2,591		$	—		$	2,591
Investment income	—			8			—			14			(8		)	14
Other income	—			—			—			97			(93		)	4
Total revenues	—			8			—			2,702			(101		)	2,609
EXPENSES
Salaries and benefits	(1		)	(50		)	—			(1,457		)	—			(1,508		)
Other operating expenses	(8		)	(63		)	1			(367		)	6			(431		)
Depreciation expense	—			(12		)	—			(47		)	—			(59		)
Amortization of intangible assets	—			—			—			(53		)	9			(44		)
Net loss on disposal of operations	—			—			—			(19		)	18			(1		)
Total expenses	(9		)	(125		)	1			(1,943		)	33			(2,043		)
OPERATING (LOSS) INCOME	(9		)	(117		)	1			759			(68		)	566
Investment income from Group undertakings	6			2,191			1,284			118			(3,599		)	—
Interest expense	(32		)	(284		)	(26		)	(210		)	455			(97		)
(LOSS) INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(35		)	1,790			1,259			667			(3,212		)	469
Income taxes	1			32			(10		)	(136		)	(1		)	(114		)
(LOSS) INCOME BEFORE INTEREST IN EARNINGS OF ASSOCIATES	(34		)	1,822			1,249			531			(3,213		)	355
Interest in earnings of associates, net of tax	—			—			—			5			7			12
Equity account for subsidiaries	393			(1,421		)	(877		)	—			1,905			—
INCOME FROM CONTINUING OPERATIONS	359			401			372			536			(1,301		)	367
Discontinued operations, net of tax	—			—			—			1			—			1
NET INCOME	359			401			372			537			(1,301		)	368
Less: Net income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	359		$	401		$	372		$	528		$	(1,301	)	$	359
Condensed Consolidating Statement of Comprehensive Income
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
Comprehensive income	$	386		$	428		$	342		$	574		$	(1,335	)	$	395
Less: comprehensive income attributable to noncontrolling interests	—			—			—			(9		)	—			(9		)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	$	386		$	428		$	342		$	565		$	(1,335	)	$	386
Condensed Consolidating Balance Sheet
	As of September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	3		$	3		$	—		$	617		$	—		$	623
Accounts receivable, net	—			26			—			930			29			985
Fiduciary assets	—			—			—			10,123			(926		)	9,197
Deferred tax assets	1			—			—			16			(3		)	14
Other current assets	1			103			1			287			(197		)	195
Total current assets	5			132			1			11,973			(1,097		)	11,014
Investments in subsidiaries	(1,187		)	3,066			3,398			3,824			(9,101		)	—
Amounts owed by (to) Group undertakings	4,053			(3,761		)	277			(569		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			69			—			404			(1		)	472
Goodwill	—			—			—			1,233			1,613			2,846
Other intangible assets, net	—			—			—			523			(162		)	361
Investments in associates	—			—			—			(53		)	237			184
Deferred tax assets	—			—			—			29			(23		)	6
Pension benefits asset	—			—			—			253			—			253
Other non-current assets	4			148			10			167			(142		)	187
Total non-current assets	4			217			10			2,556			1,522			4,309
TOTAL ASSETS	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,123		$	(926	)	$	9,197
Deferred revenue and accrued expenses	3			26			—			469			(9		)	489
Income taxes payable	—			35			15			132			(149		)	33
Short-term debt and current portion of long-term debt	—			—			15			2			—			17
Deferred tax liabilities	1			—			—			19			(2		)	18
Other current liabilities	52			24			4			327			(26		)	381
Total current liabilities	56			85			34			11,072			(1,112		)	10,135
NON-CURRENT LIABILITIES
Long-term debt	795			734			785			1			—			2,315
Liabilities for pension benefits	—			—			—			229			—			229
Deferred tax liabilities	—			—			—			59			(23		)	36
Provisions for liabilities	—			—			—			221			(13		)	208
Other non-current liabilities	—			47			—			307			(1		)	353
Total non-current liabilities	795			781			785			817			(37		)	3,141
TOTAL LIABILITIES	$	851		$	866		$	819		$	11,889		$	(1,149	)	$	13,276
EQUITY
Total Willis Group Holdings stockholders’ equity	2,024			(1,212		)	2,867			5,872			(7,527		)	2,024
Noncontrolling interests	—			—			—			23			—			23
Total equity	2,024			(1,212		)	2,867			5,895			(7,527		)	2,047
TOTAL LIABILITIES AND EQUITY	$	2,875		$	(346	)	$	3,686		$	17,784		$	(8,676	)	$	15,323
Condensed Consolidating Balance Sheet
	As of December 31, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
ASSETS
CURRENT ASSETS
Cash and cash equivalents	$	1		$	—		$	—		$	499		$	—		$	500
Accounts receivable, net	—			—			—			904			29			933
Fiduciary assets	—			—			—			10,071			(800		)	9,271
Deferred tax assets	1			—			—			18			(6		)	13
Other current assets	1			102			1			241			(164		)	181
Total current assets	3			102			1			11,733			(941		)	10,898
Investments in subsidiaries	(1,542		)	3,025			2,548			3,824			(7,855		)	—
Amounts owed by (to) Group undertakings	4,091			(3,581		)	309			(819		)	—			—
NON-CURRENT ASSETS
Fixed assets, net	—			74			—			395			(1		)	468
Goodwill	—			—			—			1,226			1,601			2,827
Other intangible assets, net	—			—			—			484			(99		)	385
Investments in associates	—			—			—			(53		)	227			174
Deferred tax assets	—			—			—			42			(24		)	18
Pension benefits asset	—			—			—			136			—			136
Other non-current assets	5			172			3			157			(131		)	206
Total non-current assets	5			246			3			2,387			1,573			4,214
TOTAL ASSETS	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
LIABILITIES AND STOCKHOLDERS’ EQUITY
CURRENT LIABILITIES
Fiduciary liabilities	$	—		$	—		$	—		$	10,071		$	(800	)	$	9,271
Deferred revenue and accrued expenses	2			—			—			543			(4		)	541
Income taxes payable	—			14			11			120			(126		)	19
Short-term debt and current portion of long-term debt	—			—			15			—			—			15
Deferred tax liabilities	1			—			—			25			(5		)	21
Other current liabilities	60			73			—			216			(22		)	327
Total current liabilities	63			87			26			10,975			(957		)	10,194
NON-CURRENT LIABILITIES
Long-term debt	795			1,268			274			1			—			2,338
Liabilities for pension benefits	—			—			—			282			—			282
Deferred tax liabilities	—			—			—			42			(24		)	18
Provisions for liabilities	—			—			—			188			(8		)	180
Other non-current liabilities	—			12			—			363			—			375
Total non-current liabilities	795			1,280			274			876			(32		)	3,193
TOTAL LIABILITIES	$	858		$	1,367		$	300		$	11,851		$	(989	)	$	13,387
EQUITY
Total Willis Group Holdings stockholders’ equity	1,699			(1,575		)	2,561			5,248			(6,234		)	1,699
Noncontrolling interests	—			—			—			26			—			26
Total equity	1,699			(1,575		)	2,561			5,274			(6,234		)	1,725
TOTAL LIABILITIES AND EQUITY	$	2,557		$	(208	)	$	2,861		$	17,125		$	(7,223	)	$	15,112
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2013
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	(120	)	$	21		$	508		$	—		$	366
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			2			—			7			—			9
Additions to fixed assets	—			(15		)	—			(63		)	—			(78		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(30		)	—			(30		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(13		)	—			(92		)	—			(105		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			—			2			—			2
Senior notes issued	—			—			522			—			—			522
Debt issuance costs	—			—			(8		)	—			—			(8		)
Repayments of debt	—			(521		)	(11		)	—			—			(532		)
Tender premium on extinguishment of debt	—			(65		)	—			—			—			(65		)
Proceeds from issue of shares	105			—			—			—			—			105
Excess tax benefits from share-based payment arrangements	1			—			—			—			—			1
Dividends paid	(144		)	—			—			—			—			(144		)
Acquisition of noncontrolling interests	—			—			—			(4		)	—			(4		)
Dividends paid to noncontrolling interests	—			—			—			(9		)	—			(9		)
Amounts owed by (to) Group undertakings	83			722			(524		)	(281		)	—			—
Net cash provided by (used in) financing activities	45			136			(21		)	(292		)	—			(132		)
INCREASE IN CASH AND CASH EQUIVALENTS	2			3			—			124			—			129
Effect of exchange rate changes on cash and cash equivalents	—			—			—			(6		)	—			(6		)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1			—			—			499			—			500
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	3		$	3		$	—		$	617		$	—		$	623
Condensed Consolidating Statement of Cash Flows
	Nine months ended September 30, 2012
	Willis			The Other			The Issuer			Other			Consolidating			Consolidated
	Group			Guarantors									adjustments
	Holdings
	(millions)
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	$	(43	)	$	1,894		$	1,259		$	146		$	(2,946	)	$	310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds on disposal of fixed and intangible assets	—			—			—			8			—			8
Additions to fixed assets	—			(19		)	—			(78		)	—			(97		)
Additions to intangible assets	—			—			—			(1		)	—			(1		)
Acquisitions of subsidiaries, net of cash acquired	—			—			—			(4		)	—			(4		)
Payments to acquire other investments	—			—			—			(5		)	—			(5		)
Net cash used in investing activities	—			(19		)	—			(80		)	—			(99		)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from draw down of revolving credit facility	—			—			20			—			—			20
Repayments of debt	—			—			(7		)	(4		)	—			(11		)
Repurchase of shares	(100		)	—			—			—			—			(100		)
Proceeds from issue of shares	41			—			—			—			—			41
Excess tax benefits from share-based payment arrangements	—			—			—			2			—			2
Dividends paid	(139		)	(1,220		)	(1,069		)	(657		)	2,946			(139		)
Proceeds from sale of noncontrolling interests	—			—			—			3			—			3
Acquisition of noncontrolling interests	—			—			—			(29		)	—			(29		)
Dividends paid to noncontrolling interests	—			—			—			(11		)	—			(11		)
Amounts owed by (to) Group undertakings	242			(818		)	(203		)	779			—			—
Net cash provided by (used in) financing activities	44			(2,038		)	(1,259		)	83			2,946			(224		)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1			(163		)	—			149			—			(13		)
Effect of exchange rate changes on cash and cash equivalents	—			—			—			1			—			1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	—			163			—			273			—			436
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	1		$	—		$	—		$	423		$	—		$	424

SALARIES_AND_BENEFITS_EXPENSE_

SALARIES AND BENEFITS EXPENSE (Additional Information) (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
		Positions
Restructuring Cost and Reserve [Line Items]	'	'	'	'	'
Restructuring and Related Cost, Number of Positions Eliminated	'	207	'	'	'
Labor and Related Expense	$541	'	$502	$1,638	$1,508
Employee Severance [Member]	'	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'	'
Severance costs	0	'	0	2	2
Expense Reduction Initiative [Member]	'	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'	'
Severance costs	'	28	'	'	'
Labor and Related Expense	'	29	'	'	'

INCOME_TAXES_Components_of_Tax

INCOME TAXES (Components of Tax Charge) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Examination [Line Items]	'	'	'	'
Ordinary income taxed at estimated annual effective tax rate, Income before tax	'	$39	'	$482
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-15	38	380	469
Ordinary income taxed at estimated annual effective tax rate, Tax amount	'	-9	'	-117
Effective Income Tax Rate On Ordinary Continuing Operations	'	24.00%	'	24.00%
Write Off Of Uncollectible Accounts Receivable Balance	'	'	'	-12
Write-off of uncollectible accounts receivable balance in North America, Tax amount	'	'	'	5
Tax amount as reported	11	10	88	114
Estimated annual effective tax rate on Non-GAAP Adjusted Income	24.00%	'	'	'
Effective tax rate on write-off of uncollectible accounts receivable balance in North America	'	'	'	41.00%
Effective tax rate as reported	-73.00%	26.00%	23.00%	24.00%
Impact Of Reduction In Uk Tax Rate On Deferred Tax Balances Before Tax	0	0	0	0
Income Tax Reconciliation, Change in Enacted Tax Rate	'	1	'	1
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate	'	0.00%	'	0.00%
Net Adjustment In Respect Of Prior Periods Income Before Tax	'	0	'	0
Income Tax Reconciliation, Prior Year Income Taxes	'	-3	'	-3
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes	'	0.00%	'	0.00%
Net Gain Loss On Disposal Of Operations	0	-1	0	-1
Non Tax Deductible Gain Loss On Disposal Of Operations Tax Amount	'	0	'	0
Effective Income Tax Rate Reconciliation, Nondeductible Expense	'	0.00%	'	0.00%
Expense Benefit Derived From Increment Reduction In Estimate Of Annual Effective Tax Rate Applied To Ordinary Before Income Tax Rate	0	0	'	'
Expense Benefit Derived From Increment Reduction In Estimate Of Annual Effective Tax Rate Applied To Ordinary Income	1	1	'	'
Expense Benefit Derived From Change In Tax Rates	0.00%	0.00%	'	'
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	'	'	35.00%	'
Non-US income tax authorities [Member]	'	'	'	'
Income Tax Examination [Line Items]	'	'	'	'
Ordinary income taxed at estimated annual effective tax rate, Income before tax	45	'	386	'
Ordinary income taxed at estimated annual effective tax rate, Tax amount	-9	'	-79	'
Effective tax rate as reported	20.00%	'	20.00%	'
Income Tax Reconciliation, Change in Enacted Tax Rate	1	'	1	'
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate	0.00%	'	0.00%	'
UNITED STATES	'	'	'	'
Income Tax Examination [Line Items]	'	'	'	'
Ordinary income taxed at estimated annual effective tax rate, Income before tax	-60	'	-6	'
Ordinary income taxed at estimated annual effective tax rate, Tax amount	($4)	'	($10)	'
Effective tax rate as reported	-7.00%	'	-167.00%	'

EARNINGS_PER_SHARE_Additional_

EARNINGS PER SHARE (Additional Information) (Details)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Outstanding Time Based Stock Options	7.8	9.2	7.8	9.2
Outstanding performance-based stock options	5.6	7.2	5.6	7.2
Restricted stock units outstanding	1.7	1.2	1.7	1.2
Antidilutive stock options	15.1	6.1	3.8	6.2

EARNINGS_PER_SHARE_Basic_and_D

EARNINGS PER SHARE (Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Net income attributable to Willis Group Holdings	($27)	$26	$297	$359
Basic average number of shares outstanding	177	173	175	173
Dilutive effect of potentially issuable shares	0	2	3	3
Diluted average number of shares outstanding	177	175	178	176
Income (Loss) from Continuing Operations, Per Basic Share	($0.15)	$0.15	$1.70	$2.07
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$0	$0	$0	$0.01
Net income attributable to Willis Group Holdings shareholders	($0.15)	$0.15	$1.70	$2.08
Dilutive effect of potentially issuable shares	$0	$0	($0.03)	($0.04)
Income (Loss) from Continuing Operations, Per Diluted Share	($0.15)	$0.15	$1.67	$2.03
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$0	$0	$0	$0.01
Net income attributable to Willis Group Holdings shareholders	($0.15)	$0.15	$1.67	$2.04

PENSION_PLANS_Components_of_Ne

PENSION PLANS (Components of Net Periodic Benefit (Income) Cost) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Net periodic benefit (income) cost	'	'	($3)	$1
UK Defined Benefit Pension Plan [Member]	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	10	9	28	26
Interest cost	26	27	80	81
Expected return on plan assets	-47	-45	-141	-135
Amortization of unrecognized prior service gain	-1	-1	-4	-4
Amortization of unrecognized actuarial loss	11	9	33	29
Net periodic benefit (income) cost	-1	-1	-4	-3
US Defined Benefit Pension Plans [Member]	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	0	0	0	0
Interest cost	10	11	29	31
Expected return on plan assets	-13	-12	-38	-35
Amortization of unrecognized prior service gain	0	0	0	0
Amortization of unrecognized actuarial loss	3	2	7	6
Net periodic benefit (income) cost	0	1	-2	2
International and US non-qualified Defined Benefit Pension Plans [Member]	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	0	1	2	3
Interest cost	2	1	5	4
Expected return on plan assets	-2	-2	-5	-5
Amortization of unrecognized prior service gain	0	0	0	0
Amortization of unrecognized actuarial loss	0	0	1	0
Net periodic benefit (income) cost	$0	$0	$3	$2

PENSION_PLANS_Additional_Infor

PENSION PLANS (Additional Information) (Details)	9 Months Ended		12 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	USD ($)	GBP (£)	USD ($)	UK Defined Benefit Pension Plan [Member]	UK Defined Benefit Pension Plan [Member]	US Defined Benefit Pension Plans [Member]	US Defined Benefit Pension Plans [Member]	International and US non-qualified Defined Benefit Pension Plans [Member]	International and US non-qualified Defined Benefit Pension Plans [Member]
				USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'	'	'	'	'	'
Cash contributions made to defined benefit pension plans	'	'	'	$68	$60	$40	$40	$8	$6
Employee cash contributions made to defined benefit pension plans	'	'	'	9	9	'	'	'	'
Estimated contributions made to defined benefit pension plans	'	'	'	88	'	'	'	'	'
Contribution related to on going calculations	'	'	'	22	'	'	'	'	'
Contribution rate for normal on-going contributions	'	'	'	15.90%	'	'	'	'	'
Contributions towards funding the deficit	'	'	'	56	'	'	'	'	'
Exceptional Contributions arising as a result of the share buyback program	'	'	10	'	'	'	'	'	'
Percentage of contribution based on profit share calculation expected for the current fiscal year	20.00%	20.00%	'	'	'	'	'	'	'
EBITDA required to trigger additional profit share contributions	900	'	'	'	'	'	'	'	'
Percentage of exceptional return calculations made to shareholders	10.00%	10.00%	'	'	'	'	'	'	'
USD value of shares repurchased in the period	'	'	100	'	'	'	'	'	'
Maximum contributions payable from deficit funding contributions and profit share contributions over the six years ended December 31, 2017	505	312	'	'	'	'	'	'	'
Estimated full year employee contributions	'	'	'	12	'	40	'	'	'
Contributions made to defined benefit pension plans	'	'	'	'	'	'	'	$11	'

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Additional Information) (Details) (USD $)

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Jul. 02, 2009

Aug. 06, 2009

Sep. 14, 2009

Sep. 16, 2010

Mar. 11, 2011

Jul. 31, 2010

Sep. 30, 2013

31-May-11

Sep. 30, 2013

Feb. 08, 2013

Feb. 14, 2013

Feb. 14, 2013

Feb. 14, 2013

Feb. 14, 2013

Feb. 14, 2013

Oct. 01, 2013

Troice [Member]

Canabal [Member]

Rupert [Member]

Casanova [Member]

Rishmague [Member]

Trident V Parallel Fund [Member]

Trident V Parallel Fund [Member]

Dowling Capital Partners I [Member]

Dowling Capital Partners I [Member]

MacArthur [Member]

Barbar [Member]

de Gadala-Maria [Member]

Ranni et ano [Member]

Tisminesky [Member]

Zacarias [Member]

Janvey [Member]

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital commitments

'

'

'

'

'

'

'

$25

'

$10

'

'

'

'

'

'

'

'

Capital contributions

5

5

'

'

'

'

'

'

15

'

2

'

'

'

'

'

'

'

Minimum damage sought

'

'

$1,000

$1,000

$300

$5

$37

'

'

'

'

$4

$30

$83.50

$3

$6.50

$12.50

$1,000

DERIVATIVE_FINANCIAL_INSTRUMEN2

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Additional Information) (Details) (USD $)

9 Months Ended

0 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2013

Jul. 22, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Jul. 22, 2013

Sep. 30, 2013

Dec. 31, 2012

Mar. 31, 2010

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Senior Notes [Member]

Seven Year Term Loan Facility [Member]

Seven Year Term Loan Facility [Member]

Revolving Credit Facility Three [Member]

Revolving Credit Facility Three [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Senior Notes Due 2015 [Member]

Senior Notes Due 2015 [Member]

Senior Notes Due 2015 [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Treasury Lock [Member]

Currency Swap [Member]

Currency Swap [Member]

Term Loan Facility [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]

Cash Flow Hedges [Member]

Fair Value Hedging [Member]

CreditFacility

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Derivative Instruments, Gain (Loss) [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization of prior loss recognized on item no longer in hedging relationship

'

'

'

'

'

'

'

'

'

'

'

($9)

$0

($13)

$0

'

'

'

'

'

'

'

'

Derivative, Notional Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

118

63

'

'

'

'

'

Fair value of swaps at close out date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

21

'

'

'

'

'

16

13

Gain in Other comprehensive income in connection with the terminated derivative instruments

'

'

'

'

'

'

'

'

'

'

'

'

'

15

'

19

'

'

'

'

'

'

'

Derivative Instruments, Gain (Loss) Expected to be Recognized in Income, Net

'

'

'

'

'

'

'

'

'

'

'

'

'

5

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

2,054

'

'

'

'

'

'

350

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5-year term loan facility balance

'

'

'

278

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity Period Of Term Loan

'

'

'

'7 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Interest Rate Description

'

'

'

'

'

'

'LIBOR plus 1.50%

'

'

'

'

'

'

'

'

'

'

'

'LIBOR plus 1.50%

'

'

'

'

Revolving credit facilities available

'

'

'

'

22

'

800

500

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Maturity Date

'

'

16-Dec-16

23-Jul-18

'

'

23-Jul-18

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Revolving Facilities

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility

'

'

'

'

2

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity date of interest rate swaps

15-Jul-15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of loan notes

'

'

'

'

'

'

'

'

5.63%

5.63%

5.63%

'

'

'

'

'

'

'

'

5.63%

5.63%

'

'

Write down of the fair value adjustment to the carrying value of senior notes in connection with interest rate swap

'

'

'

'

'

'

'

'

'

'

'

'

'

7

0

'

'

'

'

'

'

'

'

Senior Notes, Noncurrent

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5

18

'

'

Net derivative (gains) reclassified from accumulated comprehensive income into earnings within the next twelve months

15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2

'

'

'

'

'

'

'

DERIVATIVE_FINANCIAL_INSTRUMEN3

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Forward Contracts by Major Currency) (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
US Dollar [Member]	'
Derivative [Line Items]	'
Foreign currency derivatives cash flow hedges, Sell	$240
Foreign Currency Fair Value Hedge Derivative at Fair Value	14
Euro [Member]	'
Derivative [Line Items]	'
Foreign currency derivatives cash flow hedges, Sell	80
Foreign Currency Fair Value Hedge Derivative at Fair Value	-2
Japanese Yen [Member]	'
Derivative [Line Items]	'
Foreign currency derivatives cash flow hedges, Sell	39
Foreign Currency Fair Value Hedge Derivative at Fair Value	$3

DERIVATIVE_FINANCIAL_INSTRUMEN4

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Balance Sheet Disclosures) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets:	'	'
Derivative assets financial and hedging instruments, fair value	$17	$31
Liabilities:	'	'
Derivative liabilities financial and hedging instruments, fair value	2	0
Other Assets [Member] | Forward Exchange Contracts [Member]	'	'
Assets:	'	'
Derivative assets financial and hedging instruments, fair value	17	9
Other Assets [Member] | Fair Value Hedging [Member] | Interest Rate Swaps [Member]	'	'
Assets:	'	'
Derivative assets financial and hedging instruments, fair value	0	22
Other Liabilities [Member] | Forward Exchange Contracts [Member]	'	'
Liabilities:	'	'
Derivative liabilities financial and hedging instruments, fair value	$2	$0

DERIVATIVE_FINANCIAL_INSTRUMEN5

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Effects of Gains/(Losses) on Derivative Financial Instruments) (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in OCI(i) (effective element)	$24	[1]	$0	[1]	$26	[1]	$10	[1]
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)	-1	[1]	-2	[1]	-5	[1]	-5	[1]
Amount of gain (loss) recognized in income (ineffective hedges and ineffective element of effective hedges)	1		0		2		0
Interest Rate Swaps [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in OCI(i) (effective element)	0	[1]	0	[1]	0		3	[1]
Ineffectiveness recognized in interest expense	-7		0		-8		0
Interest Rate Swaps [Member] | Other Operating Expenses [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in income (ineffective hedges and ineffective element of effective hedges)	0		0		0		0
Interest Rate Swaps [Member] | Interest Expense [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)	0		'		'		'
Interest Rate Swaps [Member] | Investment Income [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)	-1	[1]	-2	[1]	-4	[1]	-5	[1]
Treasury Lock [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in OCI(i) (effective element)	3		'		19		'
Treasury Lock [Member] | Interest Expense [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in income (ineffective hedges and ineffective element of effective hedges)	1		'		2		'
Interest Expense [Member] | Investment Income [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)	'		'		0		'
Forward Exchange Contracts [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in OCI(i) (effective element)	21	[1]	0	[1]	7		7	[1]
Forward Exchange Contracts [Member] | Other Operating Expenses [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) reclassified from accumulated OCI(i) into income (effective element)	0		0	[1]	-1		0	[1]
Forward Exchange Contracts [Member] | Interest Expense [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Amount of gain (loss) recognized in income (ineffective hedges and ineffective element of effective hedges)	0		0		0		0
Fair Value Hedging [Member] | Interest Rate Swaps [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'		'		'
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	0		-1		0		-1
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0		0		0		-1
Ineffectiveness recognized in interest expense	$0		$1		$0		$2
[1]	Other Comprehensive Income

DERIVATIVE_FINANCIAL_INSTRUMEN6

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Fair Value Hedging Relationships) (Details) (Interest Rate Swaps [Member], USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Hedged item in fair value hedging relationship	'5.625% senior notes due 2015	'5.625% senior notes due 2015	'5.625% senior notes due 2015	'5.625% senior notes due 2015
Change in unrecognized gain (loss) from derivatives no longer in fair value hedging relationships	($2)	$0	($5)	$0
Amortization of prior loss recognized on item no longer in hedging relationship	-9	0	-13	0
Ineffectiveness recognized in interest expense	-7	0	-8	0
Fair Value Hedging [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Ineffectiveness recognized in interest expense	$0	$1	$0	$2

FAIR_VALUE_MEASUREMENT_Assets_

FAIR VALUE MEASUREMENT (Assets and Liabilities Measured on Recurring Basis) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'		'	'
Cash and cash equivalents	$623	$500		$424	$436
Fair Value, Measurements, Recurring [Member]	'	'		'	'
Assets at fair value:	'	'		'	'
Cash and cash equivalents	623	500		'	'
Fiduciary funds (included within Fiduciary assets)	2,099	1,796		'	'
Derivative financial instruments	17	31		'	'
Total assets	2,739	2,327		'	'
Liabilities at fair value:	'	'		'	'
Derivative financial instruments	2	'		'	'
Debt, fair value	'	18	[1]	'	'
Total liabilities	2	18		'	'
Quoted Prices In Active Markets For Identical Assets Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'	'		'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'		'	'
Cash and cash equivalents	623	'		'	'
Assets at fair value:	'	'		'	'
Cash and cash equivalents	'	500		'	'
Fiduciary funds (included within Fiduciary assets)	2,099	1,796		'	'
Derivative financial instruments	'	0		'	'
Total assets	2,722	2,296		'	'
Liabilities at fair value:	'	'		'	'
Derivative financial instruments	'	'		'	'
Debt, fair value	'	0	[1]	'	'
Total liabilities	'	0		'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'	'		'	'
Assets at fair value:	'	'		'	'
Cash and cash equivalents	0	0		'	'
Fiduciary funds (included within Fiduciary assets)	0	0		'	'
Derivative financial instruments	17	31		'	'
Total assets	17	31		'	'
Liabilities at fair value:	'	'		'	'
Derivative financial instruments	2	'		'	'
Debt, fair value	'	18	[1]	'	'
Total liabilities	2	18		'	'
Significant Other Unobservable Inputs Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'	'		'	'
Assets at fair value:	'	'		'	'
Cash and cash equivalents	0	0		'	'
Fiduciary funds (included within Fiduciary assets)	0	0		'	'
Derivative financial instruments	0	0		'	'
Total assets	0	0		'	'
Liabilities at fair value:	'	'		'	'
Derivative financial instruments	0	'		'	'
Debt, fair value	'	0	[1]	'	'
Total liabilities	$0	$0		'	'
[1]	Changes in the fair value of the underlying hedged debt instrument since inception of the hedging relationship are included in long-term debt.

FAIR_VALUE_MEASUREMENT_Estimat

FAIR VALUE MEASUREMENT (Estimated Fair Values) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Liabilities:	'	'
Long-term debt	$2,315	$2,338
Fair Value [Member]	'	'
Assets:	'	'
Derivative financial instruments	17	31
Liabilities:	'	'
Current portion of long-term debt	17	15
Long-term debt	2,440	2,576
Derivative financial instruments	2	0
Carrying Amount [Member]	'	'
Assets:	'	'
Derivative financial instruments	17	31
Liabilities:	'	'
Current portion of long-term debt	17	15
Long-term debt	2,315	2,338
Derivative financial instruments	$2	$0

GOODWILL_Goodwill_by_Segment_D

GOODWILL (Goodwill by Segment) (Details) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]	'	'	'
Tax Benefit Arising On Exercise Of Fully Vested Stock Options	$1	$0	'
Goodwill, Gross	3,338	3,319	3,295
Goodwill, Impaired, Accumulated Impairment Loss	-492	-492	0
Goodwill, Net	2,846	2,827	3,295
Purchase price allocation adjustments	'	2	'
Goodwill acquired during the period	16	12	'
Goodwill disposed of during the year	'	-1	'
Goodwill, Other Changes	-1	'	'
Goodwill, Impairment Loss	'	-492	'
Foreign exchange	4	11	'
Goodwill, Ending Balance	2,846	2,827	3,295
Global	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill, Gross	1,142	1,127	1,122
Goodwill, Impaired, Accumulated Impairment Loss	0	0	0
Goodwill, Net	1,142	1,127	1,122
Purchase price allocation adjustments	'	0	'
Goodwill acquired during the period	15	0	'
Goodwill disposed of during the year	'	0	'
Goodwill, Other Changes	0	'	'
Goodwill, Impairment Loss	'	0	'
Foreign exchange	0	5	'
Goodwill, Ending Balance	1,142	1,127	1,122
North America	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill, Gross	1,791	1,792	1,782
Goodwill, Impaired, Accumulated Impairment Loss	-492	-492	0
Goodwill, Net	1,299	1,300	1,782
Purchase price allocation adjustments	'	0	'
Goodwill acquired during the period	0	10	'
Goodwill disposed of during the year	'	0	'
Goodwill, Other Changes	-1	'	'
Goodwill, Impairment Loss	'	-492	'
Foreign exchange	0	0	'
Goodwill, Ending Balance	1,299	1,300	1,782
International	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill, Gross	405	400	391
Goodwill, Impaired, Accumulated Impairment Loss	0	0	0
Goodwill, Net	405	400	391
Purchase price allocation adjustments	'	2	'
Goodwill acquired during the period	1	2	'
Goodwill disposed of during the year	'	-1	'
Goodwill, Other Changes	0	'	'
Goodwill, Impairment Loss	'	0	'
Foreign exchange	4	6	'
Goodwill, Ending Balance	$405	$400	$391

OTHER_INTANGIBLE_ASSETS_NET_Ma

OTHER INTANGIBLE ASSETS, NET (Major Classes of Amortizable Intangible Assets) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Amortization of intangible assets	$14	$14	$42	$44	'
Gross carrying amount	710	'	710	'	738
Accumulated amortization	-349	'	-349	'	-353
Net carrying amount	361	'	361	'	385
Client Relationships [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	696	'	696	'	717
Accumulated amortization	-344	'	-344	'	-340
Net carrying amount	352	'	352	'	377
Client Lists [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	3	'	3	'	3
Accumulated amortization	-1	'	-1	'	-1
Net carrying amount	2	'	2	'	2
Non-compete Agreements [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	4	'	4	'	3
Accumulated amortization	0	'	0	'	0
Net carrying amount	4	'	4	'	3
Trade Names [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	2	'	2	'	11
Accumulated amortization	-1	'	-1	'	-10
Net carrying amount	1	'	1	'	1
Total Customer and Marketing Related [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	705	'	705	'	734
Accumulated amortization	-346	'	-346	'	-351
Net carrying amount	359	'	359	'	383
Contract based, Technology and Other [Member]	'	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'
Gross carrying amount	5	'	5	'	4
Accumulated amortization	-3	'	-3	'	-2
Net carrying amount	$2	'	$2	'	$2

OTHER_INTANGIBLE_ASSETS_NET_Ad

OTHER INTANGIBLE ASSETS, NET (Additional Information) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'	'	'	'
Amortization of intangible assets	$14	$14	$42	$44

OTHER_INTANGIBLE_ASSETS_NET_Es

OTHER INTANGIBLE ASSETS, NET (Estimated Aggregate Amortization) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'	'
Remainder of 2013	$14	'
2014	49	'
2015	41	'
2016	36	'
2017	32	'
Thereafter	189	'
Net carrying amount	$361	$385

OTHER_ASSETS_Details

OTHER ASSETS (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other current assets	'	'
Prepayments and accrued income	$82	$61
Income tax receivable	34	50
Derivatives	9	14
Debt issuance costs	3	3
Deferred compensation plan asset current	24	12
Other receivables	43	41
Total other current assets	195	181
Other non-current assets	'	'
Deferred compensation plan assets	80	97
Derivatives	8	17
Prepayments and accrued income	18	24
Debt issuance costs	16	12
Other receivables	65	56
Total other non-current assets	187	206
Total other assets	$382	$387

OTHER_LIABILITIES_Details

OTHER LIABILITIES (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other current liabilities	'	'
Accounts payable	$134	$88
Accrued dividends payable	50	47
Other taxes payable	51	44
Accrued interest payable	7	34
Derivatives	1	0
Deferred Compensation Liability, Current	24	12
Other payables	114	102
Total other current liabilities	381	327
Other non-current liabilities	'	'
Incentives from lessors	176	173
Deferred compensation plan liability	80	101
Capital lease obligation	24	28
Other payables	73	73
Total other non-current liabilities	353	375
Total other liabilities	$734	$702

DEBT_Short_term_debt_and_curre

DEBT (Short term debt and current portion of long-term debt) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified			Seven Year Term Loan Facility [Member]	Term Loan Facility Expires 2016 [Member]	Revolving Credit Facility Three [Member]	Revolving Credit Facility Three [Member]
Short-term Debt [Line Items]	'	'	'	'	'	'
Current portion of 7-year term loan facility expires 2016	'	'	$15	$15	'	'
Revolving credit facility outstanding balance at balance sheet date	'	'	'	'	2	0
Short-term debt and current portion of long-term debt	$17	$15	'	'	'	'
Maturity Period Of Term Loan	'	'	'7 years	'	'	'

DEBT_Longterm_debt_Details

DEBT (Long-term debt) (Details) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Aug. 15, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Aug. 15, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Jul. 22, 2013

In Millions, unless otherwise specified

Term Loan Facility Expires Twenty Fifteen [Member]

Term Loan Facility Expires Twenty Fifteen [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]

Four Point Six Two Five Senior Notes Due Two Thousand Twenty Three [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Seven Year Term Loan Facility [Member]

Seven Year Term Loan Facility [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]

Five Point Six Two Five Senior Notes Due Two Thousand Fifteen [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 [Member]

Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]

Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]

Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [Member]

Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [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]

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]

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]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long term debt

'

'

$1

$1

'

'

'

'

'

$263

$274

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

Senior Notes, Noncurrent

'

'

'

'

249

250

0

'

'

'

'

273

275

0

'

496

496

187

300

394

600

299

299

5

18

148

350

'

'

Revolving credit facilities available

'

'

'

'

'

'

'

800

500

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

800

500

Long-term debt, Total

$2,315

$2,338

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of loan notes

'

'

'

'

4.63%

'

'

'

'

'

'

6.13%

'

'

4.63%

5.75%

5.75%

7.00%

7.00%

6.20%

6.20%

4.13%

4.13%

5.63%

5.63%

5.63%

5.63%

'

'

Debt Instrument, Maturity Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

23-Jul-18

'

Debt Instrument, Interest Rate, Effective Percentage

'

'

'

'

4.70%

'

'

'

'

'

'

6.15%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

DEBT_Additional_Information_De

DEBT (Additional Information) (Details) (USD $)

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Jul. 22, 2013

Sep. 30, 2013

Sep. 30, 2013

Jul. 22, 2013

Sep. 30, 2013

Aug. 15, 2013

Dec. 31, 2012

Sep. 30, 2013

Aug. 15, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Seven Year Term Loan Facility [Member]

Seven Year Term Loan Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [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]

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]

Seven Year Term Loan Facility [Member]

Seven Year Term Loan Facility [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]

Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [Member]

Six Point Two Percentage Senior Notes Due Two Thousand Seventeen [Member]

Seven Percent Senior Notes Due Two Thousand Nineteen [Member]

Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]

Seven Percentage Senior Notes Due Two Thousand Nineteen [Member]

Seven Year Term Loan Facility [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt 5-year term loan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$263

$274

'

'

'

'

'

'

'

'

'

'

Revolving credit facilities available

'

'

'

'

'

'

800

500

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount of specific notes tendered and accepted for purchase

525

'

525

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Early Repayment of Senior Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

202

'

206

'

113

'

'

'

'

'

Final repayment for credit facility

'

'

'

'

'

186

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Interest Rate Description

'

'

'

'

'

'

'LIBOR plus 1.50%

'

'

'

'

'

'

'

'LIBOR plus 1.50%

'

'

'

'

'

'

'

'

'

'

'

Facility expiration date

'

'

'

'

16-Dec-16

23-Jul-18

23-Jul-18

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility outstanding balance at balance sheet date

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding Term Loan Facility Balance

'

'

'

'

'

278

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300

'

'

Senior Notes, Noncurrent

'

'

'

'

'

'

'

'

249

250

0

273

275

0

'

'

148

350

394

600

'

187

300

'

'

'

Debt Instrument, Interest Rate, Stated Percentage

'

'

'

'

'

'

'

'

4.63%

'

'

6.13%

'

'

'

'

5.63%

5.63%

6.20%

6.20%

'

7.00%

7.00%

'

'

'

Debt Instrument, Interest Rate, Effective Percentage

'

'

'

'

'

'

'

'

4.70%

'

'

6.15%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gains (Losses) on Extinguishment of Debt

60

0

60

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments of Debt Extinguishment Costs

65

'

65

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Write off of Deferred Debt Issuance Cost

'

'

2

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Write down of the fair value adjustment to the carrying value of senior notes in connection with interest rate swap

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$7

$0

SUPPLEMENTAL_DISCLOSURES_OF_CA2

SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Supplemental Cash Flow Information [Abstract]	'	'
Cash payments for income taxes, net	$36	$43
Cash payments for interest	115	117
Write off of Deferred Debt Issuance Cost	-2	0
Fair value of assets acquired, net of cash acquired	46	0
Less: Fair value of liabilities assumed	-30	0
Net assets acquired, net of cash acquired	16	0
Interest Rate Swaps [Member]	'	'
Supplemental Cash Flow Information [Abstract]	'	'
Write down of the fair value adjustment to the carrying value of senior notes in connection with interest rate swap	$7	$0

COMPREHENSIVE_INCOME_Component

COMPREHENSIVE INCOME (Components of OCI) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	$82	$35	'	'
Tax on Foreign Currency Translation Adjustment	0	0	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	82	35	-7	21
Foreign Currency Translation on Pension Funding Adjustments, Before Tax	-51	-19	3	-27
Tax on Foreign Currency Translation on Pension Funding Adjustments	14	5	-1	7
Foreign Currency Translation on Pension Funding Adjustments, Net of Tax	-37	-14	2	-20
Amortization of unrecognized actuarial loss	14	11	41	35
Tax on amortization of unrecognized actuarial loss	-3	-2	-8	-9
Amortization of unrecognized actuarial loss, Net of tax	11	9	33	26
Amortization of unrecognized prior service gain, before Tax	-1	-1	-4	-4
Tax on Amortization of unrecognized prior service gain	0	0	1	1
Amortization of unrecognized prior service gain, Net of Tax	-1	-1	-3	-3
Total Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	-38	-9	40	4
Pension and Other Postretirement Benefit Plans, Tax	11	3	-8	-1
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	-27	-6	32	3
Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	'	'	21	'
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-1	-2	-4	-4
Derivatives Qualifying as Hedges, before Tax	23	-2	21	5
Derivatives Qualifying as Hedges, Tax	-5	0	-4	-2
Derivatives Qualifying as Hedges, Net of Tax	18	-2	17	3
Other Comprehensive Income (Loss), before Tax	67	24	54	30
Other comprehensive income, Tax	6	3	-12	-3
Other Comprehensive Income (Loss), Net of Tax	73	27	42	27
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Noncontrolling Interest	-1	0	0	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	-1	0	0	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	66	24	54	30
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	6	3	-12	-3
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	72	27	42	27
Foreign Exchange Forward [Member]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	21	0	7	7
Net gain (loss) on derivative instruments, tax	-4	0	-1	-2
Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	17	0	6	5
Reclassification Adjustment on Derivatives Included in Net Income, before Tax	'	'	-1	0
Reclassification Adjustment on Derivatives Included in Net Income, Tax	'	'	0	0
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	'	'	-1	0
Interest Rate Swaps [Member]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	'	'	0	3
Net gain (loss) on derivative instruments, tax	'	'	0	-1
Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	'	'	0	2
Reclassification Adjustment on Derivatives Included in Net Income, before Tax	-1	-2	-4	-5
Reclassification Adjustment on Derivatives Included in Net Income, Tax	0	0	1	1
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-1	-2	-3	-4
Treasury Lock [Member]	'	'	'	'
Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	3	0	19	0
Net gain (loss) on derivative instruments, tax	-1	0	-4	0
Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	$2	$0	$15	$0

COMPREHENSIVE_INCOME_Component1

COMPREHENSIVE INCOME (Components of AOCI) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]	'	'	'	'	'
Foreign Currency Translation Adjustment in AOCI, Net of Tax	($41)	'	($41)	'	($34)
Pension and Other Postretirement Benefit Plans in AOCI, Net of Tax	-799	'	-799	'	-831
Net unrealized gain on derivative instruments	32	'	32	'	15
Accumulated other comprehensive loss, attributable to Willis Group Holdings, net of tax	-808	'	-808	'	-850
Foreign Currency Transaction and Translation Gain (Loss) IN AOCI Arising During Period, Net of Tax	'	'	-7	'	'
Pension and Other Postretirement Benefit Plans, Adjustment in AOCI, before Reclassification Adjustments, Net of Tax	'	'	2	'	'
Unrealized Gain (Loss) on Derivatives in AOCI Arising During Period, Net of Tax	'	'	21	'	'
Other Comprehensive Income (Loss), Before Reclassification Adjustments, Net of Tax	'	'	16	'	'
Reclassification Adjustment on Foreign Currency Transaction and Translation Gain Loss Included in Net Income, Net of Tax	'	'	0	'	'
Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	10	8	30	23	'
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-1	-2	-4	-4	'
Other Comprehensive Income (Loss), Total Reclassification Adjustment on in Net Income, Net of Tax	9	6	26	19	'
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	27	6	-32	-3	'
Derivatives Qualifying as Hedges, Net of Tax	18	-2	17	3	'
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$72	$27	$42	$27	'

COMPREHENSIVE_INCOME_Reclassif

COMPREHENSIVE INCOME (Reclassifications from OCI) (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	($1)	[1]	($2)	[1]	($5)	[1]	($5)	[1]
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	6		3		-12		-3
Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	10		8		30		23
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-1		-2		-4		-4
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax	-1		-1		-4		-4
Other Comprehensive Income (Loss), Total Reclassification Adjustment on in Net Income, Net of Tax	14		11		41		35
Pension, Total Reclassification from Other Comprehensive Income (Loss) into Net Income	13		10		37		31
Other Comprehensive Income (Loss), Total Reclassification Adjustment on in Net Income, Net of Tax	9		6		26		19
Derivative [Member]	'		'		'		'
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0		0		1		1
Interest Rate Swaps [Member]	'		'		'		'
Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	-1		-2		-3		-4
Investment Income [Member] | Interest Rate Swaps [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	-1	[1]	-2	[1]	-4	[1]	-5	[1]
Other Operating Expenses [Member] | Forward Exchange Contracts [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0		0	[1]	-1		0	[1]
Interest Expense [Member] | Interest Rate Swaps [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0		'		'		'
Cash Flow Hedges [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	-1		-2		-5		-5
Cash Flow Hedges [Member] | Investment Income [Member] | Interest Rate Swaps [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	-1		-2		-4		-5
Cash Flow Hedges [Member] | Other Operating Expenses [Member] | Forward Exchange Contracts [Member]	'		'		'		'
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0		0		-1		0
Pensions [Member]	'		'		'		'
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	($3)		($2)		($7)		($8)
[1]	Other Comprehensive Income

EQUITY_AND_NONCONTROLLING_INTE2

EQUITY AND NONCONTROLLING INTERESTS (Components of Equity) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Balance, beginning of period	'	'	$1,699		'
Net income attributable to Willis Group Holdings	-27	26	297		359
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	72	27	42		27
Comprehensive income	45	53	339		386
Dividends	'	'	-156		-152
Additional paid-in capital	'	'	137		64
Repurchase of shares (i)	'	'	0	[1]	-100	[1]
Additional noncontrolling interests	'	'	0		3
Purchase of subsidiary shares from noncontrolling interests	'	'	-4		-29
Balance, end of period	2,024	'	2,024		'
Balance, beginning of period, noncontrolling interest	'	'	26		'
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	6		9
Other comprehensive income, net of tax, portion attributable to noncontrolling interest	1	0	0		0
Comprehensive income attributable noncontrolling interest	1	0	6		9
Comprehensive income	46	53	345		395
Balance, end of period, noncontrolling interest	23	'	23		'
Balance, beginning of period, total	'	'	1,725		2,517
Net income	-27	26	303		368
Other Comprehensive Income (Loss), Net of Tax	73	27	42		27
Balance, end of period, total	2,047	2,698	2,047		2,698
Shares repurchased	'	'	'		2,796,546
Shares repurchased, average price	'	'	'		$35.87
Noncontrolling interests	'	'	'		'
Dividends	'	'	-9		-11
Additional paid-in capital	'	'	0		0
Repurchase of shares (i)	'	'	0	[1]	0	[1]
Additional noncontrolling interests	'	'	0		1
Purchase of subsidiary shares from noncontrolling interests	'	'	0		-6
Balance, beginning of period, noncontrolling interest	'	'	26		31
Net Income (Loss) Attributable to Noncontrolling Interest	'	'	6		9
Other comprehensive income, net of tax, portion attributable to noncontrolling interest	'	'	0		0
Comprehensive income attributable noncontrolling interest	'	'	6		9
Balance, end of period, noncontrolling interest	23	24	23		24
Willis Group Holdings stockholders	'	'	'		'
Balance, beginning of period	'	'	1,699		2,486
Net income attributable to Willis Group Holdings	'	'	297		359
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	'	'	42		27
Comprehensive income	'	'	339		386
Dividends	'	'	-147		-141
Additional paid-in capital	'	'	137		64
Repurchase of shares (i)	'	'	0	[1]	-100	[1]
Additional noncontrolling interests	'	'	0		2
Purchase of subsidiary shares from noncontrolling interests	'	'	-4		-23
Balance, end of period	$2,024	$2,674	$2,024		$2,674
[1]	Based on settlement date we repurchased 2,796,546 shares at an average price of $35.87 in the nine months ended September 30, 2012.

EQUITY_AND_NONCONTROLLING_INTE3

EQUITY AND NONCONTROLLING INTERESTS (Effects of Changes in Ownership Interest in Subsidiaries) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stockholders' Equity Note [Abstract]	'	'	'	'
Net income attributable to Willis Group Holdings	($27)	$26	$297	$359
Decrease in Willis Group Holdings paid-in capital for purchase of noncontrolling interests	'	'	-4	-23
Increase in Willis Group Holdings paid-in capital for sale of noncontrolling interests	'	'	0	2
Net transfers to noncontrolling interests	'	'	-4	-21
Change from net income attributable to Willis Group Holdings and transfers from noncontrolling interests	'	'	$293	$338

SEGMENT_INFORMATION_Informatio

SEGMENT INFORMATION (Information Regarding Company's Segments) (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	$791		$749		$2,722		$2,591
Investment income	4		4		11		14
Other income	0		1		3		4
Total revenues	795		754		2,736		2,609
Depreciation and amortization	35		35		110		103
Operating income	75		70		533		566
Interest in earnings of associates, net of tax	-1		-2		11		12
Global	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	250		235		938		887
Investment income	1		0		3		3
Other income	0		0		0		0
Total revenues	251		235		941		890
Depreciation and amortization	7		7		21		20
Operating income	36		52		313		325
Interest in earnings of associates, net of tax	0		0		0		0
North America	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	328		315		1,024		975
Investment income	1		2		2		3
Other income	0		1		3		4
Total revenues	329		318		1,029		982
Depreciation and amortization	9		7		27		23
Operating income	57		53		203		183
Interest in earnings of associates, net of tax	0		0		0		0
International	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	213		199		760		729
Investment income	2		2		6		8
Other income	0		0		0		0
Total revenues	215		201		766		737
Depreciation and amortization	5		7		15		16
Operating income	-9		-9		104		112
Interest in earnings of associates, net of tax	-1		-2		11		12
Total Retail	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	541		514		1,784		1,704
Investment income	3		4		8		11
Other income	0		1		3		4
Total revenues	544		519		1,795		1,719
Depreciation and amortization	14		14		42		39
Operating income	48		44		307		295
Interest in earnings of associates, net of tax	-1		-2		11		12
Total Segments	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	791		749		2,722		2,591
Investment income	4		4		11		14
Other income	0		1		3		4
Total revenues	795		754		2,736		2,609
Depreciation and amortization	21		21		63		59
Operating income	84		96		620		620
Interest in earnings of associates, net of tax	-1		-2		11		12
Corporate [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Commissions and fees	0	[1]	0	[1]	0	[1]	0	[1]
Investment income	0	[1]	0	[1]	0	[1]	0	[1]
Other income	0	[1]	0	[1]	0	[1]	0	[1]
Total revenues	0	[1]	0	[1]	0	[1]	0	[1]
Depreciation and amortization	14	[1]	14	[1]	47	[1]	44	[1]
Operating income	-9	[1]	-26	[1]	-87	[1]	-54	[1]
Interest in earnings of associates, net of tax	$0	[1]	$0	[1]	$0	[1]	$0	[1]
[1]	See the following table for an analysis of the ‘Corporate and Other’ line.

SEGMENT_INFORMATION_Corporate_

SEGMENT INFORMATION (Corporate and Other Information) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]	'	'	'	'
Amortization of intangible assets	($14)	($14)	($42)	($44)
Net Gain Loss On Disposal Of Operations	0	-1	0	-1
Joint Venture Settlement	0	-11	0	-11
Insurance Recoveries	'	'	0	5
Fees related to the extinguishment of debt	-1	0	-1	0
OPERATING INCOME	75	70	533	566
All Other Segments [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Amortization of intangible assets	-14	-14	-42	-44
Foreign exchange hedging	0	1	0	3
Foreign exchange gain on the UK pension plan asset	4	0	5	-1
Write Off Of Uncollectible Trade Receivable Balance And Associated Legal Costs	'	'	0	-13
Expense reduction initiative	'	'	-46	0
Other	2	-1	-3	8
Corporate [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
OPERATING INCOME	($9)	($26)	($87)	($54)

SEGMENT_INFORMATION_Consolidat

SEGMENT INFORMATION (Consolidated Operating Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting [Abstract]	'	'	'	'
Total consolidated operating income	$75	$70	$533	$566
Gains (Losses) on Extinguishment of Debt	-60	0	-60	0
Interest expense	-30	-32	-93	-97
(Loss) income before income taxes and interest in earnings of associates	($15)	$38	$380	$469

FINANCIAL_INFORMATION_FOR_PARE4

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Details) (USD $)	Aug. 15, 2013	Sep. 29, 2009	Mar. 28, 2007	Jul. 01, 2005
In Millions, unless otherwise specified		Willis North America, Inc. [Member]	Willis North America, Inc. [Member]	Willis North America, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Senior Notes	$525	'	'	'
Senior notes, outstanding balance	'	$187	$394	$148

FINANCIAL_INFORMATION_FOR_PARE5

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Statement of Operations) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
REVENUES	'	'	'	'
Commissions and fees	$791	$749	$2,722	$2,591
Investment income	4	4	11	14
Other income	0	1	3	4
Total revenues	795	754	2,736	2,609
EXPENSES	'	'	'	'
Salaries and benefits	-541	-502	-1,638	-1,508
Other operating expenses	-144	-146	-455	-431
Depreciation expense	-21	-21	-68	-59
Amortization of intangible assets	-14	-14	-42	-44
Net Gain Loss On Disposal Of Operations	0	-1	0	-1
Total expenses	-720	-684	-2,203	-2,043
Operating income	75	70	533	566
Investment income from Group undertakings	0	0	0	0
Gains (Losses) on Extinguishment of Debt	-60	0	-60	0
Interest expense	-30	-32	-93	-97
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-15	38	380	469
Income taxes	-11	-10	-88	-114
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-26	28	292	355
Interest in earnings of associates, net of tax	-1	-2	11	12
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0	1
NET (LOSS) INCOME	-27	26	303	368
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	303	367
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
Willis Group Holdings	'	'	'	'
REVENUES	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	0	0	0	0
Other income	0	0	0	0
Total revenues	0	0	0	0
EXPENSES	'	'	'	'
Salaries and benefits	0	0	-1	-1
Other operating expenses	3	-1	-2	-8
Depreciation expense	0	0	0	0
Amortization of intangible assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Total expenses	3	-1	-3	-9
Operating income	3	-1	-3	-9
Investment income from Group undertakings	0	6	0	6
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest expense	-11	-11	-32	-32
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-8	-6	-35	-35
Income taxes	0	-6	0	1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-8	-12	-35	-34
Interest in earnings of associates, net of tax	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	-27	26	297	359
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
Equity account for subsidiaries	-19	38	332	393
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	'	359
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
The Other Guarantors	'	'	'	'
REVENUES	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	3	2	9	8
Other income	0	0	0	0
Total revenues	3	2	9	8
EXPENSES	'	'	'	'
Salaries and benefits	0	0	0	0
Other operating expenses	-7	-1	-38	1
Depreciation expense	-1	0	-2	-1
Amortization of intangible assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Total expenses	-8	-1	-40	0
Operating income	-5	1	-31	8
Investment income from Group undertakings	93	808	265	994
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest expense	-52	-61	-151	-188
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	36	748	83	814
Income taxes	2	0	8	3
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	38	748	91	817
Interest in earnings of associates, net of tax	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	-20	47	328	401
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
Equity account for subsidiaries	-58	-701	237	-416
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	'	47	'	401
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-20	47	328	401
The Issuer	'	'	'	'
REVENUES	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	0	0	0	0
Other income	0	0	0	0
Total revenues	0	0	0	0
EXPENSES	'	'	'	'
Salaries and benefits	-48	-28	-93	-50
Other operating expenses	-43	-8	-128	-63
Depreciation expense	-5	-4	-16	-11
Amortization of intangible assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Total expenses	-96	-40	-237	-124
Operating income	-96	-40	-237	-124
Investment income from Group undertakings	60	63	195	193
Gains (Losses) on Extinguishment of Debt	-60	'	-60	'
Interest expense	-31	-48	-97	-122
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-127	-25	-199	-53
Income taxes	0	9	0	19
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-127	-16	-199	-34
Interest in earnings of associates, net of tax	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	-65	1	-15	36
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
Equity account for subsidiaries	62	17	184	70
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	'	1	'	36
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-65	1	-15	36
Other	'	'	'	'
REVENUES	'	'	'	'
Commissions and fees	791	749	2,722	2,591
Investment income	4	4	11	14
Other income	34	1	-149	97
Total revenues	829	754	2,584	2,702
EXPENSES	'	'	'	'
Salaries and benefits	-493	-474	-1,544	-1,457
Other operating expenses	-122	-139	-368	-367
Depreciation expense	-15	-17	-50	-47
Amortization of intangible assets	-16	-17	-48	-53
Net Gain Loss On Disposal Of Operations	-8	4	-5	-19
Total expenses	-654	-643	-2,015	-1,943
Operating income	175	111	569	759
Investment income from Group undertakings	20	104	68	118
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest expense	-83	-68	-256	-210
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	112	147	381	667
Income taxes	-7	-19	-94	-136
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	105	128	287	531
Interest in earnings of associates, net of tax	-4	-5	4	5
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	1
NET (LOSS) INCOME	101	123	291	537
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	101	123	'	536
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	101	123	285	528
Consolidating adjustments	'	'	'	'
REVENUES	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	-3	-2	-9	-8
Other income	-34	0	152	-93
Total revenues	-37	-2	143	-101
EXPENSES	'	'	'	'
Salaries and benefits	0	0	0	0
Other operating expenses	25	3	81	6
Depreciation expense	0	0	0	0
Amortization of intangible assets	2	3	6	9
Net Gain Loss On Disposal Of Operations	8	-5	5	18
Total expenses	35	1	92	33
Operating income	-2	-1	235	-68
Investment income from Group undertakings	-173	-981	-528	-1,311
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest expense	147	156	443	455
INCOME BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	-28	-826	150	-924
Income taxes	-6	6	-2	-1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-34	-820	148	-925
Interest in earnings of associates, net of tax	3	3	7	7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	-16	-171	-598	-965
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
Equity account for subsidiaries	15	646	-753	-47
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	'	-171	'	-965
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	($16)	($171)	($598)	($965)

FINANCIAL_INFORMATION_FOR_PARE6

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Comprehensive Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Comprehensive income	$46	$53	$345	$395
Less: comprehensive income attributable to noncontrolling interests	-1	0	-6	-9
Comprehensive income	45	53	339	386
Willis Group Holdings	'	'	'	'
Comprehensive income	45	53	339	386
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	45	53	339	386
The Other Guarantors	'	'	'	'
Comprehensive income	51	74	369	428
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	51	74	369	428
The Issuer	'	'	'	'
Comprehensive income	-62	2	-8	41
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	-62	2	-8	41
Other	'	'	'	'
Comprehensive income	155	144	298	574
Less: comprehensive income attributable to noncontrolling interests	-1	0	-6	-9
Comprehensive income	154	144	292	565
Consolidating adjustments	'	'	'	'
Comprehensive income	-143	-220	-653	-1,034
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	($143)	($220)	($653)	($1,034)

FINANCIAL_INFORMATION_FOR_PARE7

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Balance Sheet) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	$623	$500	$424	$436
Accounts receivable, net	985	933	'	'
Fiduciary assets	9,197	9,271	'	'
Deferred tax assets	14	13	'	'
Other current assets	195	181	'	'
Total current assets	11,014	10,898	'	'
Investments in subsidiaries	0	0	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	472	468	'	'
Goodwill	2,846	2,827	'	3,295
Other intangible assets, net	361	385	'	'
Investments in associates	184	174	'	'
Deferred tax assets	6	18	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	187	206	'	'
Total non-current assets	4,309	4,214	'	'
TOTAL ASSETS	15,323	15,112	'	'
Fiduciary liabilities	9,197	9,271	'	'
Deferred revenue and accrued expenses	489	541	'	'
Income taxes payable	33	19	'	'
Short-term debt and current portion of long-term debt	17	15	'	'
Deferred tax liabilities	18	21	'	'
Other current liabilities	381	327	'	'
Total current liabilities	10,135	10,194	'	'
Long-term debt	2,315	2,338	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	36	18	'	'
Provisions for liabilities	208	180	'	'
Other non-current liabilities	353	375	'	'
Total non-current liabilities	3,141	3,193	'	'
TOTAL LIABILITIES	13,276	13,387	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	23	26	'	'
Total equity	2,047	1,725	2,698	2,517
TOTAL LIABILITIES AND EQUITY	15,323	15,112	'	'
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	3	1	1	0
Accounts receivable, net	0	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	1	1	'	'
Other current assets	1	1	'	'
Total current assets	5	3	'	'
Investments in subsidiaries	-1,187	-1,542	'	'
Amounts owed by (to) Group undertakings	4,053	4,091	'	'
Fixed assets, net	0	0	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	4	5	'	'
Total non-current assets	4	5	'	'
TOTAL ASSETS	2,875	2,557	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	3	2	'	'
Income taxes payable	0	0	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	1	1	'	'
Other current liabilities	52	60	'	'
Total current liabilities	56	63	'	'
Long-term debt	795	795	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	0	0	'	'
Total non-current liabilities	795	795	'	'
TOTAL LIABILITIES	851	858	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	0	0	'	'
Total equity	2,024	1,699	'	'
TOTAL LIABILITIES AND EQUITY	2,875	2,557	'	'
The Other Guarantors	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	3	0	0	0
Accounts receivable, net	0	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	0	0	'	'
Other current assets	93	65	'	'
Total current assets	96	65	'	'
Investments in subsidiaries	2,747	2,493	'	'
Amounts owed by (to) Group undertakings	-3,361	-3,959	'	'
Fixed assets, net	13	11	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	151	134	'	'
Total non-current assets	164	145	'	'
TOTAL ASSETS	-354	-1,256	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	0	0	'	'
Income taxes payable	50	25	'	'
Short-term debt and current portion of long-term debt	15	15	'	'
Deferred tax liabilities	0	0	'	'
Other current liabilities	8	0	'	'
Total current liabilities	73	40	'	'
Long-term debt	785	274	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	0	5	'	'
Total non-current liabilities	785	279	'	'
TOTAL LIABILITIES	858	319	'	'
Total Willis Group Holdings stockholders’ equity	-1,212	-1,575	'	'
Noncontrolling interests	0	0	'	'
Total equity	-1,212	-1,575	'	'
TOTAL LIABILITIES AND EQUITY	-354	-1,256	'	'
The Issuer	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	0	163
Accounts receivable, net	26	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	0	0	'	'
Other current assets	11	38	'	'
Total current assets	37	38	'	'
Investments in subsidiaries	844	553	'	'
Amounts owed by (to) Group undertakings	-123	687	'	'
Fixed assets, net	56	63	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	7	41	'	'
Total non-current assets	63	104	'	'
TOTAL ASSETS	821	1,382	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	26	0	'	'
Income taxes payable	0	0	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	0	0	'	'
Other current liabilities	20	73	'	'
Total current liabilities	46	73	'	'
Long-term debt	734	1,268	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	47	7	'	'
Total non-current liabilities	781	1,275	'	'
TOTAL LIABILITIES	827	1,348	'	'
Total Willis Group Holdings stockholders’ equity	-6	34	'	'
Noncontrolling interests	0	0	'	'
Total equity	-6	34	'	'
TOTAL LIABILITIES AND EQUITY	821	1,382	'	'
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	617	499	423	273
Accounts receivable, net	930	904	'	'
Fiduciary assets	10,123	10,071	'	'
Deferred tax assets	16	18	'	'
Other current assets	287	241	'	'
Total current assets	11,973	11,733	'	'
Investments in subsidiaries	3,824	3,824	'	'
Amounts owed by (to) Group undertakings	-569	-819	'	'
Fixed assets, net	404	395	'	'
Goodwill	1,233	1,226	'	'
Other intangible assets, net	523	484	'	'
Investments in associates	-53	-53	'	'
Deferred tax assets	29	42	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	167	157	'	'
Total non-current assets	2,556	2,387	'	'
TOTAL ASSETS	17,784	17,125	'	'
Fiduciary liabilities	10,123	10,071	'	'
Deferred revenue and accrued expenses	469	543	'	'
Income taxes payable	132	120	'	'
Short-term debt and current portion of long-term debt	2	0	'	'
Deferred tax liabilities	19	25	'	'
Other current liabilities	327	216	'	'
Total current liabilities	11,072	10,975	'	'
Long-term debt	1	1	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	59	42	'	'
Provisions for liabilities	221	188	'	'
Other non-current liabilities	307	363	'	'
Total non-current liabilities	817	876	'	'
TOTAL LIABILITIES	11,889	11,851	'	'
Total Willis Group Holdings stockholders’ equity	5,872	5,248	'	'
Noncontrolling interests	23	26	'	'
Total equity	5,895	5,274	'	'
TOTAL LIABILITIES AND EQUITY	17,784	17,125	'	'
Consolidating adjustments	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	29	29	'	'
Fiduciary assets	-926	-800	'	'
Deferred tax assets	-3	-6	'	'
Other current assets	-197	-164	'	'
Total current assets	-1,097	-941	'	'
Investments in subsidiaries	-6,228	-5,328	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	-1	-1	'	'
Goodwill	1,613	1,601	'	'
Other intangible assets, net	-162	-99	'	'
Investments in associates	237	227	'	'
Deferred tax assets	-23	-24	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	-142	-131	'	'
Total non-current assets	1,522	1,573	'	'
TOTAL ASSETS	-5,803	-4,696	'	'
Fiduciary liabilities	-926	-800	'	'
Deferred revenue and accrued expenses	-9	-4	'	'
Income taxes payable	-149	-126	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	-2	-5	'	'
Other current liabilities	-26	-22	'	'
Total current liabilities	-1,112	-957	'	'
Long-term debt	0	0	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	-23	-24	'	'
Provisions for liabilities	-13	-8	'	'
Other non-current liabilities	-1	0	'	'
Total non-current liabilities	-37	-32	'	'
TOTAL LIABILITIES	-1,149	-989	'	'
Total Willis Group Holdings stockholders’ equity	-4,654	-3,707	'	'
Noncontrolling interests	0	0	'	'
Total equity	-4,654	-3,707	'	'
TOTAL LIABILITIES AND EQUITY	($5,803)	($4,696)	'	'

FINANCIAL_INFORMATION_FOR_PARE8

FINANCIAL INFORMATION FOR PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Cash Flows) (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Mar. 17, 2011	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	$366	$310	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	9	8	'	'
Additions to fixed assets	'	'	-78	-97	'	'
Payments to Acquire Intangible Assets	'	'	-1	-1	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	-30	-4	'	'
Payments to acquire other investments	'	'	-5	-5	'	'
Net cash used in investing activities	'	'	-105	-99	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	2	20	'	'
Payments of Debt Issuance Costs	'	'	-8	0	'	'
Senior notes issued	800	'	'	'	'	'
Repayments of debt	'	'	-532	-11	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	522	0	'	'
Payments of Debt Extinguishment Costs	'	-65	-65	0	'	'
Repurchase of shares	'	'	0	-100	'	'
Proceeds from issue of shares	'	'	105	41	'	'
Amounts owed by (to) Group undertakings	'	'	0	0	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	1	2	'	'
Dividends paid	'	'	-144	-139	'	'
Proceeds from Noncontrolling Interests	'	'	0	3	'	'
Acquisition of noncontrolling interests	'	'	-4	-29	'	'
Dividends paid to noncontrolling interests	'	'	-9	-11	'	'
Net cash used in continuing financing activities	'	'	-132	-224	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	129	-13	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	-6	1	'	'
Cash and cash equivalents	'	623	623	424	500	436
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	623	623	424	500	436
Willis Group Holdings	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	-43	-43	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	0	0	'	'
Additions to fixed assets	'	'	0	0	'	'
Payments to Acquire Intangible Assets	'	'	0	0	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0	'	'
Payments to acquire other investments	'	'	0	0	'	'
Net cash used in investing activities	'	'	0	0	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	0	'	'
Payments of Debt Issuance Costs	'	'	0	'	'	'
Repayments of debt	'	'	0	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	'	0	'	'	'
Repurchase of shares	'	'	'	-100	'	'
Proceeds from issue of shares	'	'	105	41	'	'
Amounts owed by (to) Group undertakings	'	'	83	242	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	1	0	'	'
Dividends paid	'	'	-144	-139	'	'
Proceeds from Noncontrolling Interests	'	'	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0	'	'
Dividends paid to noncontrolling interests	'	'	0	0	'	'
Net cash used in continuing financing activities	'	'	45	44	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	2	1	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0	'	'
Cash and cash equivalents	'	3	3	1	1	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	3	3	1	1	0
The Other Guarantors	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	103	803	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	0	0	'	'
Additions to fixed assets	'	'	-4	-6	'	'
Payments to Acquire Intangible Assets	'	'	0	0	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0	'	'
Payments to acquire other investments	'	'	0	0	'	'
Net cash used in investing activities	'	'	-4	-6	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	20	'	'
Payments of Debt Issuance Costs	'	'	-8	'	'	'
Repayments of debt	'	'	-11	-7	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	522	'	'	'
Payments of Debt Extinguishment Costs	'	'	0	'	'	'
Repurchase of shares	'	'	'	0	'	'
Proceeds from issue of shares	'	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	'	-599	-810	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	0	'	'
Dividends paid	'	'	0	0	'	'
Proceeds from Noncontrolling Interests	'	'	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0	'	'
Dividends paid to noncontrolling interests	'	'	0	0	'	'
Net cash used in continuing financing activities	'	'	-96	-797	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	3	0	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0	'	'
Cash and cash equivalents	'	3	3	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	3	3	0	0	0
The Issuer	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	-202	61	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	2	0	'	'
Additions to fixed assets	'	'	-11	-13	'	'
Payments to Acquire Intangible Assets	'	'	0	0	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0	'	'
Payments to acquire other investments	'	'	0	0	'	'
Net cash used in investing activities	'	'	-9	-13	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	0	'	'
Payments of Debt Issuance Costs	'	'	0	'	'	'
Repayments of debt	'	'	-521	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	'	-65	'	'	'
Repurchase of shares	'	'	'	0	'	'
Proceeds from issue of shares	'	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	'	797	-211	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	0	'	'
Dividends paid	'	'	0	0	'	'
Proceeds from Noncontrolling Interests	'	'	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0	'	'
Dividends paid to noncontrolling interests	'	'	0	0	'	'
Net cash used in continuing financing activities	'	'	211	-211	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	0	-163	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0	'	'
Cash and cash equivalents	'	0	0	0	0	163
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	0	0	0	0	163
Other	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	508	146	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	7	8	'	'
Additions to fixed assets	'	'	-63	-78	'	'
Payments to Acquire Intangible Assets	'	'	-1	-1	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	-30	-4	'	'
Payments to acquire other investments	'	'	-5	-5	'	'
Net cash used in investing activities	'	'	-92	-80	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	2	0	'	'
Payments of Debt Issuance Costs	'	'	0	'	'	'
Repayments of debt	'	'	0	-4	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	'	0	'	'	'
Repurchase of shares	'	'	'	0	'	'
Proceeds from issue of shares	'	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	'	-281	779	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	2	'	'
Dividends paid	'	'	0	-657	'	'
Proceeds from Noncontrolling Interests	'	'	'	3	'	'
Acquisition of noncontrolling interests	'	'	-4	-29	'	'
Dividends paid to noncontrolling interests	'	'	-9	-11	'	'
Net cash used in continuing financing activities	'	'	-292	83	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	124	149	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	-6	1	'	'
Cash and cash equivalents	'	617	617	423	499	273
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	617	617	423	499	273
Consolidating adjustments	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	0	-657	'	'
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	0	0	'	'
Additions to fixed assets	'	'	0	0	'	'
Payments to Acquire Intangible Assets	'	'	0	0	'	'
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0	'	'
Payments to acquire other investments	'	'	0	0	'	'
Net cash used in investing activities	'	'	0	0	'	'
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	0	'	'
Payments of Debt Issuance Costs	'	'	0	'	'	'
Repayments of debt	'	'	0	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	'	0	'	'	'
Repurchase of shares	'	'	'	0	'	'
Proceeds from issue of shares	'	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	'	0	0	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	0	'	'
Dividends paid	'	'	0	657	'	'
Proceeds from Noncontrolling Interests	'	'	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0	'	'
Dividends paid to noncontrolling interests	'	'	0	0	'	'
Net cash used in continuing financing activities	'	'	0	657	'	'
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	0	0	'	'
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0	'	'
Cash and cash equivalents	'	0	0	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	$0	$0	$0	$0	$0

FINANCIAL_INFORMATION_FOR_PARE9

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Details) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Mar. 17, 2011
Financial Information for Parent Issuer Guarantor Subsidiaries and Non-Guarantor Subsidiaries Disclosure [Abstract]	'
Senior notes issued	$800

Recovered_Sheet1

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Statement of Operations) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Commissions and fees	$791	$749	$2,722	$2,591
Investment income	4	4	11	14
Other income	0	1	3	4
Total revenues	795	754	2,736	2,609
Labor and Related Expense	-541	-502	-1,638	-1,508
Other Cost and Expense, Operating	-144	-146	-455	-431
Depreciation expense	-21	-21	-68	-59
Amortization of intangible assets	-14	-14	-42	-44
Net Gain Loss On Disposal Of Operations	0	-1	0	-1
Operating Expenses	-720	-684	-2,203	-2,043
Operating Income (Loss)	75	70	533	566
Investment income from Group undertakings	0	0	0	0
Gains (Losses) on Extinguishment of Debt	-60	0	-60	0
Interest Expense	-30	-32	-93	-97
(Loss) income before income taxes and interest in earnings of associates	-15	38	380	469
Income Tax Expense (Benefit)	-11	-10	-88	-114
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-26	28	292	355
Interest in earnings of associates, net of tax	-1	-2	11	12
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0	1
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	303	367
NET (LOSS) INCOME	-27	26	303	368
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
Guarantor Subsidiaries [Member]	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	3	2	9	8
Other income	0	0	0	0
Total revenues	3	2	9	8
Labor and Related Expense	-48	-28	-93	-50
Other Cost and Expense, Operating	-50	-9	-166	-62
Depreciation expense	-6	-4	-18	-12
Amortization of intangible assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Operating Expenses	-104	-41	-277	-124
Operating Income (Loss)	-101	-39	-268	-116
Investment income from Group undertakings	153	871	460	1,187
Gains (Losses) on Extinguishment of Debt	'	'	-60	'
Extinguishment of Debt, Amount	-60	'	'	'
Interest Expense	-83	-109	-248	-310
(Loss) income before income taxes and interest in earnings of associates	-91	723	-116	761
Income Tax Expense (Benefit)	2	9	8	22
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-89	732	-108	783
Interest in earnings of associates, net of tax	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	'	'	0
Equity account for subsidiaries	69	-685	436	-382
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	'	47	'	401
NET (LOSS) INCOME	-20	47	328	401
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-20	47	328	401
Other	'	'	'	'
Commissions and fees	791	749	2,722	2,591
Investment income	4	4	11	14
Other income	34	1	-149	97
Total revenues	829	754	2,584	2,702
Labor and Related Expense	-493	-474	-1,544	-1,457
Other Cost and Expense, Operating	-122	-139	-368	-367
Depreciation expense	-15	-17	-50	-47
Amortization of intangible assets	-16	-17	-48	-53
Net Gain Loss On Disposal Of Operations	-8	4	-5	-19
Operating Expenses	-654	-643	-2,015	-1,943
Operating Income (Loss)	175	111	569	759
Investment income from Group undertakings	20	104	68	118
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Extinguishment of Debt, Amount	0	'	'	'
Interest Expense	-83	-68	-256	-210
(Loss) income before income taxes and interest in earnings of associates	112	147	381	667
Income Tax Expense (Benefit)	-7	-19	-94	-136
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	105	128	287	531
Interest in earnings of associates, net of tax	-4	-5	4	5
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	1
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	101	123	'	536
NET (LOSS) INCOME	101	123	291	537
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	101	123	285	528
Consolidating adjustments	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	-3	-2	-9	-8
Other income	-34	0	152	-93
Total revenues	-37	-2	143	-101
Labor and Related Expense	0	0	0	0
Other Cost and Expense, Operating	25	3	81	6
Depreciation expense	0	0	0	0
Amortization of intangible assets	2	3	6	9
Net Gain Loss On Disposal Of Operations	8	-5	5	18
Operating Expenses	35	1	92	33
Operating Income (Loss)	-2	-1	235	-68
Investment income from Group undertakings	-173	-981	-528	-1,311
Gains (Losses) on Extinguishment of Debt	'	'	0	'
Extinguishment of Debt, Amount	0	'	'	'
Interest Expense	147	156	443	455
(Loss) income before income taxes and interest in earnings of associates	-28	-826	150	-924
Income Tax Expense (Benefit)	-6	6	-2	-1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-34	-820	148	-925
Interest in earnings of associates, net of tax	3	3	7	7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	'	'	0
Equity account for subsidiaries	-50	647	-768	-11
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	'	-170	'	-929
NET (LOSS) INCOME	-81	-170	-613	-929
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-81	-170	-613	-929
Willis Group Holdings	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	0	0	0	0
Other income	0	0	0	0
Total revenues	0	0	0	0
Labor and Related Expense	0	0	-1	-1
Other Cost and Expense, Operating	3	-1	-2	-8
Depreciation expense	0	0	0	0
Amortization of intangible assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Operating Expenses	3	-1	-3	-9
Operating Income (Loss)	3	-1	-3	-9
Investment income from Group undertakings	0	6	0	6
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Extinguishment of Debt, Amount	0	'	'	'
Interest Expense	-11	-11	-32	-32
(Loss) income before income taxes and interest in earnings of associates	-8	-6	-35	-35
Income Tax Expense (Benefit)	0	-6	0	1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-8	-12	-35	-34
Interest in earnings of associates, net of tax	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
Equity account for subsidiaries	-19	38	332	393
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	'	359
NET (LOSS) INCOME	-27	26	297	359
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	($27)	$26	$297	$359

Recovered_Sheet2

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Comprehensive Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive income	$46	$53	$345	$395
Less: comprehensive income attributable to noncontrolling interests	-1	0	-6	-9
Comprehensive income	45	53	339	386
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive income	45	53	339	386
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	45	53	339	386
Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive income	51	74	369	428
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	51	74	369	428
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive income	155	144	298	574
Less: comprehensive income attributable to noncontrolling interests	-1	0	-6	-9
Comprehensive income	154	144	292	565
Consolidating adjustments	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive income	-205	-218	-661	-993
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income	($205)	($218)	($661)	($993)

Recovered_Sheet3

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Balance Sheet) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	$623	$500	$424	$436
Accounts receivable, net	985	933	'	'
Fiduciary assets	9,197	9,271	'	'
Deferred tax assets	14	13	'	'
Other current assets	195	181	'	'
Total current assets	11,014	10,898	'	'
Investments in subsidiaries	0	0	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	472	468	'	'
Goodwill	2,846	2,827	'	3,295
Other intangible assets, net	361	385	'	'
Investments in associates	184	174	'	'
Deferred tax assets	6	18	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	187	206	'	'
Total non-current assets	4,309	4,214	'	'
TOTAL ASSETS	15,323	15,112	'	'
Fiduciary liabilities	9,197	9,271	'	'
Deferred revenue and accrued expenses	489	541	'	'
Income taxes payable	33	19	'	'
Short-term debt and current portion of long-term debt	17	15	'	'
Deferred tax liabilities	18	21	'	'
Other current liabilities	381	327	'	'
Total current liabilities	10,135	10,194	'	'
Long-term debt	2,315	2,338	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	36	18	'	'
Provisions for liabilities	208	180	'	'
Other non-current liabilities	353	375	'	'
Total non-current liabilities	3,141	3,193	'	'
TOTAL LIABILITIES	13,276	13,387	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	23	26	'	'
Total equity	2,047	1,725	2,698	2,517
TOTAL LIABILITIES AND EQUITY	15,323	15,112	'	'
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	3	1	1	0
Accounts receivable, net	0	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	1	1	'	'
Other current assets	1	1	'	'
Total current assets	5	3	'	'
Investments in subsidiaries	-1,187	-1,542	'	'
Amounts owed by (to) Group undertakings	4,053	4,091	'	'
Fixed assets, net	0	0	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	4	5	'	'
Total non-current assets	4	5	'	'
TOTAL ASSETS	2,875	2,557	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	3	2	'	'
Income taxes payable	0	0	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	1	1	'	'
Other current liabilities	52	60	'	'
Total current liabilities	56	63	'	'
Long-term debt	795	795	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	0	0	'	'
Total non-current liabilities	795	795	'	'
TOTAL LIABILITIES	851	858	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	0	0	'	'
Total equity	2,024	1,699	'	'
TOTAL LIABILITIES AND EQUITY	2,875	2,557	'	'
Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	3	0	0	163
Accounts receivable, net	26	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	0	0	'	'
Other current assets	104	103	'	'
Total current assets	133	103	'	'
Investments in subsidiaries	3,597	3,012	'	'
Amounts owed by (to) Group undertakings	-3,484	-3,272	'	'
Fixed assets, net	69	74	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	158	175	'	'
Total non-current assets	227	249	'	'
TOTAL ASSETS	473	92	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	26	0	'	'
Income taxes payable	50	25	'	'
Short-term debt and current portion of long-term debt	15	15	'	'
Deferred tax liabilities	0	0	'	'
Other current liabilities	28	73	'	'
Total current liabilities	119	113	'	'
Long-term debt	1,519	1,542	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	47	12	'	'
Total non-current liabilities	1,566	1,554	'	'
TOTAL LIABILITIES	1,685	1,667	'	'
Total Willis Group Holdings stockholders’ equity	-1,212	-1,575	'	'
Noncontrolling interests	0	0	'	'
Total equity	-1,212	-1,575	'	'
TOTAL LIABILITIES AND EQUITY	473	92	'	'
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	617	499	423	273
Accounts receivable, net	930	904	'	'
Fiduciary assets	10,123	10,071	'	'
Deferred tax assets	16	18	'	'
Other current assets	287	241	'	'
Total current assets	11,973	11,733	'	'
Investments in subsidiaries	3,824	3,824	'	'
Amounts owed by (to) Group undertakings	-569	-819	'	'
Fixed assets, net	404	395	'	'
Goodwill	1,233	1,226	'	'
Other intangible assets, net	523	484	'	'
Investments in associates	-53	-53	'	'
Deferred tax assets	29	42	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	167	157	'	'
Total non-current assets	2,556	2,387	'	'
TOTAL ASSETS	17,784	17,125	'	'
Fiduciary liabilities	10,123	10,071	'	'
Deferred revenue and accrued expenses	469	543	'	'
Income taxes payable	132	120	'	'
Short-term debt and current portion of long-term debt	2	0	'	'
Deferred tax liabilities	19	25	'	'
Other current liabilities	327	216	'	'
Total current liabilities	11,072	10,975	'	'
Long-term debt	1	1	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	59	42	'	'
Provisions for liabilities	221	188	'	'
Other non-current liabilities	307	363	'	'
Total non-current liabilities	817	876	'	'
TOTAL LIABILITIES	11,889	11,851	'	'
Total Willis Group Holdings stockholders’ equity	5,872	5,248	'	'
Noncontrolling interests	23	26	'	'
Total equity	5,895	5,274	'	'
TOTAL LIABILITIES AND EQUITY	17,784	17,125	'	'
Consolidating adjustments	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	29	29	'	'
Fiduciary assets	-926	-800	'	'
Deferred tax assets	-3	-6	'	'
Other current assets	-197	-164	'	'
Total current assets	-1,097	-941	'	'
Investments in subsidiaries	-6,234	-5,294	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	-1	-1	'	'
Goodwill	1,613	1,601	'	'
Other intangible assets, net	-162	-99	'	'
Investments in associates	237	227	'	'
Deferred tax assets	-23	-24	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	-142	-131	'	'
Total non-current assets	1,522	1,573	'	'
TOTAL ASSETS	-5,809	-4,662	'	'
Fiduciary liabilities	-926	-800	'	'
Deferred revenue and accrued expenses	-9	-4	'	'
Income taxes payable	-149	-126	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	-2	-5	'	'
Other current liabilities	-26	-22	'	'
Total current liabilities	-1,112	-957	'	'
Long-term debt	0	0	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	-23	-24	'	'
Provisions for liabilities	-13	-8	'	'
Other non-current liabilities	-1	0	'	'
Total non-current liabilities	-37	-32	'	'
TOTAL LIABILITIES	-1,149	-989	'	'
Total Willis Group Holdings stockholders’ equity	-4,660	-3,673	'	'
Noncontrolling interests	0	0	'	'
Total equity	-4,660	-3,673	'	'
TOTAL LIABILITIES AND EQUITY	($5,809)	($4,662)	'	'

Recovered_Sheet4

FINANCIAL INFORMATION FOR PARENT ISSUER, GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Cash Flows) (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Mar. 17, 2011	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	$366	$310
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	9	8
Additions to fixed assets	'	'	-78	-97
Payments to Acquire Intangible Assets	'	'	-1	-1
Acquisitions of subsidiaries, net of cash acquired	'	'	-30	-4
Payments to acquire other investments	'	'	-5	-5
Net cash used in investing activities	'	'	-105	-99
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	2	20
Proceeds from Issuance of Senior Long-term Debt	'	'	522	0
Payments of Debt Issuance Costs	'	'	8	0
Senior notes issued	800	'	'	'
Repayments of debt	'	'	-532	-11
Payments of Debt Extinguishment Costs	'	65	65	0
Repurchase of shares	'	'	0	-100
Proceeds from issue of shares	'	'	105	41
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	1	2
Dividends paid	'	'	-144	-139
Proceeds from Noncontrolling Interests	'	'	0	3
Acquisition of noncontrolling interests	'	'	-4	-29
Dividends paid to noncontrolling interests	'	'	-9	-11
Amounts owed by (to) Group undertakings	'	'	0	0
Net cash used in continuing financing activities	'	'	-132	-224
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	129	-13
Effect of exchange rate changes on cash and cash equivalents	'	'	-6	1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	'	'	500	436
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	623	623	424
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	-43	-43
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	0	0
Additions to fixed assets	'	'	0	0
Payments to Acquire Intangible Assets	'	'	0	0
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0
Payments to acquire other investments	'	'	0	0
Net cash used in investing activities	'	'	0	0
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	0
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'
Payments of Debt Issuance Costs	'	'	0	'
Repayments of debt	'	'	0	0
Payments of Debt Extinguishment Costs	'	'	0	'
Repurchase of shares	'	'	'	-100
Proceeds from issue of shares	'	'	105	41
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	1	0
Dividends paid	'	'	-144	-139
Proceeds from Noncontrolling Interests	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0
Dividends paid to noncontrolling interests	'	'	0	0
Amounts owed by (to) Group undertakings	'	'	83	242
Net cash used in continuing financing activities	'	'	45	44
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	2	1
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	'	'	1	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	3	3	1
Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	-99	864
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	2	0
Additions to fixed assets	'	'	-15	-19
Payments to Acquire Intangible Assets	'	'	0	0
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0
Payments to acquire other investments	'	'	0	0
Net cash used in investing activities	'	'	-13	-19
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	20
Proceeds from Issuance of Senior Long-term Debt	'	'	522	'
Payments of Debt Issuance Costs	'	'	8	'
Repayments of debt	'	'	-532	-7
Payments of Debt Extinguishment Costs	'	'	65	'
Repurchase of shares	'	'	'	'
Proceeds from issue of shares	'	'	0	0
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	0
Dividends paid	'	'	0	0
Proceeds from Noncontrolling Interests	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0
Dividends paid to noncontrolling interests	'	'	0	0
Amounts owed by (to) Group undertakings	'	'	198	-1,021
Net cash used in continuing financing activities	'	'	115	-1,008
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	3	-163
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	'	'	0	163
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	3	3	0
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	508	146
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	7	8
Additions to fixed assets	'	'	-63	-78
Payments to Acquire Intangible Assets	'	'	-1	-1
Acquisitions of subsidiaries, net of cash acquired	'	'	-30	-4
Payments to acquire other investments	'	'	-5	-5
Net cash used in investing activities	'	'	-92	-80
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	2	0
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'
Payments of Debt Issuance Costs	'	'	0	'
Repayments of debt	'	'	0	-4
Payments of Debt Extinguishment Costs	'	'	0	'
Repurchase of shares	'	'	'	0
Proceeds from issue of shares	'	'	0	0
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	2
Dividends paid	'	'	0	-657
Proceeds from Noncontrolling Interests	'	'	'	3
Acquisition of noncontrolling interests	'	'	-4	-29
Dividends paid to noncontrolling interests	'	'	-9	-11
Amounts owed by (to) Group undertakings	'	'	-281	779
Net cash used in continuing financing activities	'	'	-292	83
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	124	149
Effect of exchange rate changes on cash and cash equivalents	'	'	-6	1
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	'	'	499	273
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	617	617	423
Consolidating adjustments	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	'	0	-657
CASH FLOWS FROM INVESTING ACTIVITIES	'	'	'	'
Proceeds on disposal of fixed and intangible assets	'	'	0	0
Additions to fixed assets	'	'	0	0
Payments to Acquire Intangible Assets	'	'	0	0
Acquisitions of subsidiaries, net of cash acquired	'	'	0	0
Payments to acquire other investments	'	'	0	0
Net cash used in investing activities	'	'	0	0
CASH FLOWS FROM FINANCING ACTIVITIES	'	'	'	'
Proceeds from draw down of revolving credit facility	'	'	0	0
Proceeds from Issuance of Senior Long-term Debt	'	'	0	'
Payments of Debt Issuance Costs	'	'	0	'
Repayments of debt	'	'	0	0
Payments of Debt Extinguishment Costs	'	'	0	'
Repurchase of shares	'	'	'	'
Proceeds from issue of shares	'	'	0	0
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	'	0	0
Dividends paid	'	'	0	657
Proceeds from Noncontrolling Interests	'	'	'	'
Acquisition of noncontrolling interests	'	'	0	0
Dividends paid to noncontrolling interests	'	'	0	0
Amounts owed by (to) Group undertakings	'	'	0	0
Net cash used in continuing financing activities	'	'	0	657
INCREASE IN CASH AND CASH EQUIVALENTS	'	'	0	0
Effect of exchange rate changes on cash and cash equivalents	'	'	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	'	'	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	'	$0	$0	$0

FINANCIAL_INFORMATION_FOR_ISSU2

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Statement of operations) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	$791	$749	$2,722	$2,591
Investment income	4	4	11	14
Other income	0	1	3	4
Total revenues	795	754	2,736	2,609
Labor and Related Expense	-541	-502	-1,638	-1,508
Other Cost and Expense, Operating	-144	-146	-455	-431
Depreciation	-21	-21	-68	-59
Amortization of Intangible Assets	-14	-14	-42	-44
Net Gain Loss On Disposal Of Operations	0	-1	0	-1
Operating Expenses	-720	-684	-2,203	-2,043
Operating Income (Loss)	75	70	533	566
Investment income from Group undertakings	0	0	0	0
Gains (Losses) on Extinguishment of Debt	-60	0	-60	0
Interest Expense	-30	-32	-93	-97
(Loss) income before income taxes and interest in earnings of associates	-15	38	380	469
Income Tax Expense (Benefit)	-11	-10	-88	-114
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-26	28	292	355
Interest in earnings of associates, net of tax	-1	-2	11	12
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	303	367
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	0	1
NET (LOSS) INCOME	-27	26	303	368
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	0	0	0	0
Other income	0	0	0	0
Total revenues	0	0	0	0
Labor and Related Expense	0	0	-1	-1
Other Cost and Expense, Operating	3	-1	-2	-8
Depreciation	0	0	0	0
Amortization of Intangible Assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Operating Expenses	3	-1	-3	-9
Operating Income (Loss)	3	-1	-3	-9
Investment income from Group undertakings	0	6	0	6
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest Expense	-11	-11	-32	-32
(Loss) income before income taxes and interest in earnings of associates	-8	-6	-35	-35
Income Tax Expense (Benefit)	0	-6	0	1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-8	-12	-35	-34
Interest in earnings of associates, net of tax	0	0	0	0
Equity account for subsidiaries	-19	38	332	393
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-27	26	'	359
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-27	26	297	359
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	-27	26	297	359
Guarantor companies [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	3	2	9	8
Other income	0	0	0	0
Total revenues	3	2	9	8
Labor and Related Expense	-48	-28	-93	-50
Other Cost and Expense, Operating	-50	-9	-166	-63
Depreciation	-6	-4	-18	-12
Amortization of Intangible Assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Operating Expenses	-104	-41	-277	-125
Operating Income (Loss)	-101	-39	-268	-117
Investment income from Group undertakings	137	1,743	415	2,191
Gains (Losses) on Extinguishment of Debt	-60	'	-60	'
Interest Expense	-71	-100	-219	-284
(Loss) income before income taxes and interest in earnings of associates	-95	1,604	-132	1,790
Income Tax Expense (Benefit)	4	14	12	32
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-91	1,618	-120	1,822
Interest in earnings of associates, net of tax	0	0	0	0
Equity account for subsidiaries	71	-1,571	448	-1,421
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-20	47	'	401
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-20	47	328	401
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	'	47	328	401
Trinity Acquisition Plc [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	0	0	0	0
Other income	0	0	0	0
Total revenues	0	0	0	0
Labor and Related Expense	0	0	0	0
Other Cost and Expense, Operating	0	0	0	1
Depreciation	0	0	0	0
Amortization of Intangible Assets	0	0	0	0
Net Gain Loss On Disposal Of Operations	0	0	0	0
Operating Expenses	0	0	0	1
Operating Income (Loss)	0	0	0	1
Investment income from Group undertakings	16	966	45	1,284
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest Expense	-12	-9	-29	-26
(Loss) income before income taxes and interest in earnings of associates	4	957	16	1,259
Income Tax Expense (Benefit)	-2	-5	-4	-10
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	2	952	12	1,249
Interest in earnings of associates, net of tax	0	0	0	0
Equity account for subsidiaries	-35	-913	275	-877
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-33	39	'	372
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-33	39	287	372
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	'	39	287	372
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	791	749	2,722	2,591
Investment income	4	4	11	14
Other income	34	1	-149	97
Total revenues	829	754	2,584	2,702
Labor and Related Expense	-493	-474	-1,544	-1,457
Other Cost and Expense, Operating	-122	-139	-368	-367
Depreciation	-15	-17	-50	-47
Amortization of Intangible Assets	-16	-17	-48	-53
Net Gain Loss On Disposal Of Operations	-8	4	-5	-19
Operating Expenses	-654	-643	-2,015	-1,943
Operating Income (Loss)	175	111	569	759
Investment income from Group undertakings	20	104	68	118
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest Expense	-83	-68	-256	-210
(Loss) income before income taxes and interest in earnings of associates	112	147	381	667
Income Tax Expense (Benefit)	-7	-19	-94	-136
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	105	128	287	531
Interest in earnings of associates, net of tax	-4	-5	4	5
Equity account for subsidiaries	0	0	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	101	123	'	536
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	-6	-9
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	101	123	285	528
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	1
NET (LOSS) INCOME	101	123	291	537
Consolidation entries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Commissions and fees	0	0	0	0
Investment income	-3	-2	-9	-8
Other income	-34	0	152	-93
Total revenues	-37	-2	143	-101
Labor and Related Expense	0	0	0	0
Other Cost and Expense, Operating	25	3	81	6
Depreciation	0	0	0	0
Amortization of Intangible Assets	2	3	6	9
Net Gain Loss On Disposal Of Operations	8	-5	5	18
Operating Expenses	35	1	92	33
Operating Income (Loss)	-2	-1	235	-68
Investment income from Group undertakings	-173	-2,819	-528	-3,599
Gains (Losses) on Extinguishment of Debt	0	'	0	'
Interest Expense	147	156	443	455
(Loss) income before income taxes and interest in earnings of associates	-28	-2,664	150	-3,212
Income Tax Expense (Benefit)	-6	6	-2	-1
Income Loss From Continuing Operations Before Interest In Earnings Of Associates	-34	-2,658	148	-3,213
Interest in earnings of associates, net of tax	3	3	7	7
Equity account for subsidiaries	-17	2,446	-1,055	1,905
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-48	-209	'	-1,301
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS GROUP HOLDINGS	-48	-209	-900	-1,301
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	'	0	'	0
NET (LOSS) INCOME	'	($209)	($900)	($1,301)

FINANCIAL_INFORMATION_FOR_ISSU3

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Comprehensive income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$46	$53	$345	$395
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	-1	0	-6	-9
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	45	53	339	386
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	45	53	339	386
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	45	53	339	386
Guarantor companies [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	51	74	369	428
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	51	74	369	428
Trinity Acquisition Plc [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	31	8	326	342
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	31	8	326	342
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	155	144	298	574
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	-1	0	-6	-9
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	154	144	292	565
Consolidation entries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	-236	-226	-987	-1,335
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	($236)	($226)	($987)	($1,335)

FINANCIAL_INFORMATION_FOR_ISSU4

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Balance sheet) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	$623	$500	$424	$436
Accounts receivable, net	985	933	'	'
Fiduciary assets	9,197	9,271	'	'
Deferred tax assets	14	13	'	'
Other current assets	195	181	'	'
Total current assets	11,014	10,898	'	'
Investments in subsidiaries	0	0	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	472	468	'	'
Goodwill	2,846	2,827	'	3,295
Other intangible assets, net	361	385	'	'
Investments in associates	184	174	'	'
Deferred tax assets	6	18	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	187	206	'	'
Total non-current assets	4,309	4,214	'	'
Assets	15,323	15,112	'	'
Fiduciary liabilities	9,197	9,271	'	'
Deferred revenue and accrued expenses	489	541	'	'
Income taxes payable	33	19	'	'
Short-term debt and current portion of long-term debt	17	15	'	'
Deferred tax liabilities	18	21	'	'
Other current liabilities	381	327	'	'
Total current liabilities	10,135	10,194	'	'
Long-term debt	2,315	2,338	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	36	18	'	'
Provisions for liabilities	208	180	'	'
Other non-current liabilities	353	375	'	'
Total non-current liabilities	3,141	3,193	'	'
TOTAL LIABILITIES	13,276	13,387	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	23	26	'	'
Total equity	2,047	1,725	2,698	2,517
TOTAL LIABILITIES AND EQUITY	15,323	15,112	'	'
Willis Group Holdings	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	3	1	1	0
Accounts receivable, net	0	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	1	1	'	'
Other current assets	1	1	'	'
Total current assets	5	3	'	'
Investments in subsidiaries	-1,187	-1,542	'	'
Amounts owed by (to) Group undertakings	4,053	4,091	'	'
Fixed assets, net	0	0	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	4	5	'	'
Total non-current assets	4	5	'	'
Assets	2,875	2,557	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	3	2	'	'
Income taxes payable	0	0	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	1	1	'	'
Other current liabilities	52	60	'	'
Total current liabilities	56	63	'	'
Long-term debt	795	795	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	0	0	'	'
Total non-current liabilities	795	795	'	'
TOTAL LIABILITIES	851	858	'	'
Total Willis Group Holdings stockholders’ equity	2,024	1,699	'	'
Noncontrolling interests	0	0	'	'
Total equity	2,024	1,699	'	'
TOTAL LIABILITIES AND EQUITY	2,875	2,557	'	'
Guarantor companies [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	3	0	0	163
Accounts receivable, net	26	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	0	0	'	'
Other current assets	103	102	'	'
Total current assets	132	102	'	'
Investments in subsidiaries	3,066	3,025	'	'
Amounts owed by (to) Group undertakings	-3,761	-3,581	'	'
Fixed assets, net	69	74	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	148	172	'	'
Total non-current assets	217	246	'	'
Assets	-346	-208	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	26	0	'	'
Income taxes payable	35	14	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	0	0	'	'
Other current liabilities	24	73	'	'
Total current liabilities	85	87	'	'
Long-term debt	734	1,268	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	47	12	'	'
Total non-current liabilities	781	1,280	'	'
TOTAL LIABILITIES	866	1,367	'	'
Total Willis Group Holdings stockholders’ equity	-1,212	-1,575	'	'
Noncontrolling interests	0	0	'	'
Total equity	-1,212	-1,575	'	'
TOTAL LIABILITIES AND EQUITY	-346	-208	'	'
Trinity Acquisition Plc [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0	0
Accounts receivable, net	0	0	'	'
Fiduciary assets	0	0	'	'
Deferred tax assets	0	0	'	'
Other current assets	1	1	'	'
Total current assets	1	1	'	'
Investments in subsidiaries	3,398	2,548	'	'
Amounts owed by (to) Group undertakings	277	309	'	'
Fixed assets, net	0	0	'	'
Goodwill	0	0	'	'
Other intangible assets, net	0	0	'	'
Investments in associates	0	0	'	'
Deferred tax assets	0	0	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	10	3	'	'
Total non-current assets	10	3	'	'
Assets	3,686	2,861	'	'
Fiduciary liabilities	0	0	'	'
Deferred revenue and accrued expenses	0	0	'	'
Income taxes payable	15	11	'	'
Short-term debt and current portion of long-term debt	15	15	'	'
Deferred tax liabilities	0	0	'	'
Other current liabilities	4	0	'	'
Total current liabilities	34	26	'	'
Long-term debt	785	274	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	0	0	'	'
Provisions for liabilities	0	0	'	'
Other non-current liabilities	0	0	'	'
Total non-current liabilities	785	274	'	'
TOTAL LIABILITIES	819	300	'	'
Total Willis Group Holdings stockholders’ equity	2,867	2,561	'	'
Noncontrolling interests	0	0	'	'
Total equity	2,867	2,561	'	'
TOTAL LIABILITIES AND EQUITY	3,686	2,861	'	'
Other	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	617	499	423	273
Accounts receivable, net	930	904	'	'
Fiduciary assets	10,123	10,071	'	'
Deferred tax assets	16	18	'	'
Other current assets	287	241	'	'
Total current assets	11,973	11,733	'	'
Investments in subsidiaries	3,824	3,824	'	'
Amounts owed by (to) Group undertakings	-569	-819	'	'
Fixed assets, net	404	395	'	'
Goodwill	1,233	1,226	'	'
Other intangible assets, net	523	484	'	'
Investments in associates	-53	-53	'	'
Deferred tax assets	29	42	'	'
Pension benefits asset	253	136	'	'
Other non-current assets	167	157	'	'
Total non-current assets	2,556	2,387	'	'
Assets	17,784	17,125	'	'
Fiduciary liabilities	10,123	10,071	'	'
Deferred revenue and accrued expenses	469	543	'	'
Income taxes payable	132	120	'	'
Short-term debt and current portion of long-term debt	2	0	'	'
Deferred tax liabilities	19	25	'	'
Other current liabilities	327	216	'	'
Total current liabilities	11,072	10,975	'	'
Long-term debt	1	1	'	'
Liabilities for pension benefits	229	282	'	'
Deferred tax liabilities	59	42	'	'
Provisions for liabilities	221	188	'	'
Other non-current liabilities	307	363	'	'
Total non-current liabilities	817	876	'	'
TOTAL LIABILITIES	11,889	11,851	'	'
Total Willis Group Holdings stockholders’ equity	5,872	5,248	'	'
Noncontrolling interests	23	26	'	'
Total equity	5,895	5,274	'	'
TOTAL LIABILITIES AND EQUITY	17,784	17,125	'	'
Consolidation entries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0	0
Accounts receivable, net	29	29	'	'
Fiduciary assets	-926	-800	'	'
Deferred tax assets	-3	-6	'	'
Other current assets	-197	-164	'	'
Total current assets	-1,097	-941	'	'
Investments in subsidiaries	-9,101	-7,855	'	'
Amounts owed by (to) Group undertakings	0	0	'	'
Fixed assets, net	-1	-1	'	'
Goodwill	1,613	1,601	'	'
Other intangible assets, net	-162	-99	'	'
Investments in associates	237	227	'	'
Deferred tax assets	-23	-24	'	'
Pension benefits asset	0	0	'	'
Other non-current assets	-142	-131	'	'
Total non-current assets	1,522	1,573	'	'
Assets	-8,676	-7,223	'	'
Fiduciary liabilities	-926	-800	'	'
Deferred revenue and accrued expenses	-9	-4	'	'
Income taxes payable	-149	-126	'	'
Short-term debt and current portion of long-term debt	0	0	'	'
Deferred tax liabilities	-2	-5	'	'
Other current liabilities	-26	-22	'	'
Total current liabilities	-1,112	-957	'	'
Long-term debt	0	0	'	'
Liabilities for pension benefits	0	0	'	'
Deferred tax liabilities	-23	-24	'	'
Provisions for liabilities	-13	-8	'	'
Other non-current liabilities	-1	0	'	'
Total non-current liabilities	-37	-32	'	'
TOTAL LIABILITIES	-1,149	-989	'	'
Total Willis Group Holdings stockholders’ equity	-7,527	-6,234	'	'
Noncontrolling interests	0	0	'	'
Total equity	-7,527	-6,234	'	'
TOTAL LIABILITIES AND EQUITY	($8,676)	($7,223)	'	'

FINANCIAL_INFORMATION_FOR_ISSU5

FINANCIAL INFORMATION FOR ISSUER, PARENT GUARANTOR, OTHER GUARANTOR SUBSIDIARIES AND NON-GUARANTOR SUBSIDIARIES (Cash flows) (Details) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	$366	$310	'	'
Proceeds on disposal of fixed and intangible assets	'	9	8	'	'
Payments to Acquire Property, Plant, and Equipment	'	-78	-97	'	'
Payments to Acquire Intangible Assets	'	-1	-1	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	-30	-4	'	'
Payments to Acquire Other Investments	'	-5	-5	'	'
Net cash used in investing activities	'	-105	-99	'	'
Proceeds from Other Debt	'	2	20	'	'
Payments of Debt Issuance Costs	'	-8	0	'	'
Repayments of Other Debt	'	-532	-11	'	'
Proceeds from Issuance of Senior Long-term Debt	'	522	0	'	'
Payments of Debt Extinguishment Costs	-65	-65	0	'	'
Proceeds from issue of shares	'	105	41	'	'
Amounts owed by (to) Group undertakings	'	0	0	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	1	2	'	'
Payments of Ordinary Dividends, Common Stock	'	-144	-139	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	-4	-29	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	-9	-11	'	'
Net Cash Provided by (Used in) Financing Activities	'	-132	-224	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	129	-13	'	'
Effect of exchange rate changes on cash and cash equivalents	'	-6	1	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	623	623	424	500	436
Payments for Repurchase of Common Stock	'	0	-100	'	'
Payments to Noncontrolling Interests	'	'	3	'	'
Willis Group Holdings	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	-43	-43	'	'
Proceeds on disposal of fixed and intangible assets	'	0	0	'	'
Payments to Acquire Property, Plant, and Equipment	'	0	0	'	'
Payments to Acquire Intangible Assets	'	0	0	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	0	0	'	'
Payments to Acquire Other Investments	'	0	0	'	'
Net cash used in investing activities	'	0	0	'	'
Proceeds from Other Debt	'	0	0	'	'
Payments of Debt Issuance Costs	'	0	'	'	'
Repayments of Other Debt	'	0	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	0	'	'	'
Proceeds from issue of shares	'	105	41	'	'
Amounts owed by (to) Group undertakings	'	83	242	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	1	0	'	'
Payments of Ordinary Dividends, Common Stock	'	-144	-139	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	0	0	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	0	0	'	'
Net Cash Provided by (Used in) Financing Activities	'	45	44	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	2	1	'	'
Effect of exchange rate changes on cash and cash equivalents	'	0	0	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	3	3	1	1	0
Payments for Repurchase of Common Stock	'	'	-100	'	'
Payments to Noncontrolling Interests	'	'	0	'	'
Guarantor companies [Member]	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	-120	1,894	'	'
Proceeds on disposal of fixed and intangible assets	'	2	0	'	'
Payments to Acquire Property, Plant, and Equipment	'	-15	-19	'	'
Payments to Acquire Intangible Assets	'	0	0	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	0	0	'	'
Payments to Acquire Other Investments	'	0	0	'	'
Net cash used in investing activities	'	-13	-19	'	'
Proceeds from Other Debt	'	0	0	'	'
Payments of Debt Issuance Costs	'	0	'	'	'
Repayments of Other Debt	'	-521	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	-65	'	'	'
Proceeds from issue of shares	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	722	-818	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	0	0	'	'
Payments of Ordinary Dividends, Common Stock	'	0	-1,220	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	0	0	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	0	0	'	'
Net Cash Provided by (Used in) Financing Activities	'	136	-2,038	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	3	-163	'	'
Effect of exchange rate changes on cash and cash equivalents	'	0	0	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	3	3	0	0	163
Payments for Repurchase of Common Stock	'	'	0	'	'
Payments to Noncontrolling Interests	'	'	0	'	'
Trinity Acquisition Plc [Member]	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	21	1,259	'	'
Proceeds on disposal of fixed and intangible assets	'	0	0	'	'
Payments to Acquire Property, Plant, and Equipment	'	0	0	'	'
Payments to Acquire Intangible Assets	'	0	0	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	0	0	'	'
Payments to Acquire Other Investments	'	0	0	'	'
Net cash used in investing activities	'	0	0	'	'
Proceeds from Other Debt	'	0	20	'	'
Payments of Debt Issuance Costs	'	-8	'	'	'
Repayments of Other Debt	'	-11	-7	'	'
Proceeds from Issuance of Senior Long-term Debt	'	522	'	'	'
Payments of Debt Extinguishment Costs	'	0	'	'	'
Proceeds from issue of shares	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	-524	-203	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	0	0	'	'
Payments of Ordinary Dividends, Common Stock	'	0	-1,069	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	0	0	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	0	0	'	'
Net Cash Provided by (Used in) Financing Activities	'	-21	-1,259	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	0	0	'	'
Effect of exchange rate changes on cash and cash equivalents	'	0	0	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0	0	0
Payments for Repurchase of Common Stock	'	'	0	'	'
Payments to Noncontrolling Interests	'	'	0	'	'
Other	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	508	146	'	'
Proceeds on disposal of fixed and intangible assets	'	7	8	'	'
Payments to Acquire Property, Plant, and Equipment	'	-63	-78	'	'
Payments to Acquire Intangible Assets	'	-1	-1	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	-30	-4	'	'
Payments to Acquire Other Investments	'	-5	-5	'	'
Net cash used in investing activities	'	-92	-80	'	'
Proceeds from Other Debt	'	2	0	'	'
Payments of Debt Issuance Costs	'	0	'	'	'
Repayments of Other Debt	'	0	-4	'	'
Proceeds from Issuance of Senior Long-term Debt	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	0	'	'	'
Proceeds from issue of shares	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	-281	779	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	0	2	'	'
Payments of Ordinary Dividends, Common Stock	'	0	-657	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	-4	-29	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	-9	-11	'	'
Net Cash Provided by (Used in) Financing Activities	'	-292	83	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	124	149	'	'
Effect of exchange rate changes on cash and cash equivalents	'	-6	1	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	617	617	423	499	273
Payments for Repurchase of Common Stock	'	'	0	'	'
Payments to Noncontrolling Interests	'	'	3	'	'
Consolidation entries [Member]	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'
Net Cash Provided by (Used in) Operating Activities	'	0	-2,946	'	'
Proceeds on disposal of fixed and intangible assets	'	0	0	'	'
Payments to Acquire Property, Plant, and Equipment	'	0	0	'	'
Payments to Acquire Intangible Assets	'	0	0	'	'
Payments to Acquire Businesses, Net of Cash Acquired	'	0	0	'	'
Payments to Acquire Other Investments	'	0	0	'	'
Net cash used in investing activities	'	0	0	'	'
Proceeds from Other Debt	'	0	0	'	'
Payments of Debt Issuance Costs	'	0	'	'	'
Repayments of Other Debt	'	0	0	'	'
Proceeds from Issuance of Senior Long-term Debt	'	0	'	'	'
Payments of Debt Extinguishment Costs	'	0	'	'	'
Proceeds from issue of shares	'	0	0	'	'
Amounts owed by (to) Group undertakings	'	0	0	'	'
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	'	0	0	'	'
Payments of Ordinary Dividends, Common Stock	'	0	2,946	'	'
Payments to Acquire Additional Interest in Subsidiaries	'	0	0	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	0	0	'	'
Net Cash Provided by (Used in) Financing Activities	'	0	2,946	'	'
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	'	0	0	'	'
Effect of exchange rate changes on cash and cash equivalents	'	0	0	'	'
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0	0	0
Payments for Repurchase of Common Stock	'	'	0	'	'
Payments to Noncontrolling Interests	'	'	$0	'	'