Willis Towers Watson Public Limited (WTW) 10-K/A 6 Jun 18 2017 FY Annual report (amended) Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 23, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	Willis Towers Watson Plc.
Entity Central Index Key	1,140,536
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	true
Amendment Description	This Amendment No. 1 on Form 10-K/A (the ‘Amendment’) amends Willis Towers Watson Public Limited Company’s (the ‘Company’) Annual Report on Form 10-K for the year ended December 31, 2017, as originally filed with the Securities and Exchange Commission on February 28, 2018 (the ‘Original Filing’). The Company is filing this Amendment solely to include an additional paragraph in the opinion on the 2017 financial statements of its independent auditor, Deloitte and Touche LLP, describing their procedures performed in auditing the 2017 adjustments of the Company’s reportable segment structure and adoption of ASU 2016-09 on a full retrospective basis to prior years, and their opinion on the appropriateness and proper application of such adjustments.
Entity Common Stock, Shares Outstanding		132,216,177
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 18,544,137,403

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Commissions and fees	$ 8,116	$ 7,778	$ 3,809
Interest and other income	86	109	20
Total revenues	8,202	7,887	3,829
Costs of providing services
Salaries and benefits	4,745	4,646	2,303
Other operating expenses	1,534	1,551	718
Depreciation	203	178	95
Amortization	581	591	76
Restructuring costs	132	193	126
Transaction and integration expenses	269	177	84
Total costs of providing services	7,464	7,336	3,402
Income from operations	738	551	427
Interest expense	188	184	142
Other expense/(income), net	61	27	(55)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	489	340	340
Benefit from income taxes	(100)	(96)	(33)
INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES	589	436	373
Interest in earnings of associates, net of tax	3	2	11
NET INCOME	592	438	384
Income attributable to non-controlling interests	(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$ 568	$ 420	$ 373
Earnings/(loss) per share
Basic earnings per share (usd per share)	$ 4.21	$ 3.07	$ 5.49	[1],[2]
Diluted earnings per share (usd per share)	4.18	3.04	5.41	[1],[2]
Cash dividends declared per share (usd per share)	$ 2.12	$ 1.92	$ 3.28	[1]
Other comprehensive income/(loss), net of tax:
Foreign currency translation	$ 295	$ (353)	$ (133)
Defined pension and post-retirement benefits	14	(439)	180
Derivative instruments	75	(75)	(28)
Other comprehensive income/(loss), net of tax, before non-controlling interests	384	(867)	19
Comprehensive income/(loss) before non-controlling interests	976	(429)	403
Comprehensive (income)/loss attributable to non-controlling interests	(37)	2	(1)
Comprehensive income/(loss) attributable to Willis Towers Watson	$ 939	$ (427)	$ 402
[1]	Basic and diluted earnings per share and cash dividends declared per share, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.
[2]	Shares outstanding, potentially issuable shares, basic and diluted earnings per share, and the dilutive effect of potentially issuable shares, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split effected on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 1,030	$ 870
Fiduciary assets	12,155	10,505
Accounts receivable, net	2,246	2,080
Prepaid and other current assets	430	337
Total current assets	15,861	13,792
Fixed assets, net	985	839
Goodwill	10,519	10,413
Other intangible assets, net	3,882	4,368
Pension benefits assets	764	488
Other non-current assets	447	353
Total non-current assets	16,597	16,461
TOTAL ASSETS	32,458	30,253
LIABILITIES AND EQUITY
Fiduciary liabilities	12,155	10,505
Deferred revenue and accrued expenses	1,711	1,481
Short-term debt and current portion of long-term debt	85	508
Other current liabilities	804	876
Total current liabilities	14,755	13,370
Long-term debt	4,450	3,357
Liability for pension benefits	1,259	1,321
Deferred tax liabilities	615	864
Provision for liabilities	558	575
Other non-current liabilities	544	532
Total non-current liabilities	7,426	6,649
TOTAL LIABILITIES	22,181	20,019
COMMITMENTS AND CONTINGENCIES
REDEEMABLE NON-CONTROLLING INTEREST	28	51
EQUITY (i)
Additional paid-in capital	10,538	10,596
Retained earnings	1,104	1,452
Accumulated other comprehensive loss, net of tax	(1,513)	(1,884)
Treasury shares, at cost, 17,519 in 2017 and 795,816 in 2016, and 40,000 shares, €1 nominal value, in 2017 and 2016	(3)	(99)
Total Willis Towers Watson shareholders’ equity	10,126	10,065
Non-controlling interests	123	118
Total equity	10,249	10,183
TOTAL LIABILITIES AND EQUITY	$ 32,458	$ 30,253

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2017$ / sharesshares	Dec. 31, 2017€ / sharesshares	Dec. 31, 2016$ / sharesshares	Dec. 31, 2016€ / sharesshares
Preference shares, nominal value (usd per share) | $ / shares	$ 0.000115		$ 0.000115
Preference shares, shares authorized	1,000,000,000	1,000,000,000	1,000,000,000	1,000,000,000
Preference shares, shares issued	0	0	0	0
Ordinary shares, $0.000304635 nominal value; Authorized: 1,510,003,775; Issued: 132,139,581 and 137,075,068; Outstanding: 132,139,581 and 136,296,771
Ordinary shares, nominal value (usd and Euro per share) | $ / shares	$ 0.000304635		$ 0.000304635
Ordinary shares, shares authorized	1,510,003,775	1,510,003,775	1,510,003,775	1,510,003,775
Ordinary shares, shares issued	132,139,581	132,139,581	137,075,068	137,075,068
Common shares outstanding	132,139,581	132,139,581	136,296,771	136,296,771
Treasury shares	17,519	17,519	795,816	795,816
Ordinary shares, €1 nominal value; Authorized: 40,000; Issued 40,000 shares in 2017 and 2016
Ordinary shares, nominal value (usd and Euro per share) | € / shares		€ 1		€ 1
Ordinary shares, shares authorized	40,000	40,000	40,000	40,000
Ordinary shares, shares issued	40,000	40,000	40,000	40,000
Treasury stock, nominal value (in Eur per share) | € / shares		1		1
Treasury shares	40,000	40,000	40,000	40,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME	$ 592		$ 438	$ 384
Adjustments to reconcile net income to total net cash from operating activities:
Depreciation	252	[1]	178	95
Amortization	581		591	76
Net periodic benefit of defined benefit pension plans	(91)		(93)	(78)
Provision for doubtful receivables from clients	17		36	5
Benefit from deferred income taxes	(285)		(244)	(99)
Share-based compensation	67		123	64
Non-cash foreign exchange loss/(gain)	77		(28)	73
Net gain on disposal of operations and fixed and intangible assets and gain on re-measurement of equity interests	(13)		0	(90)
Other, net	(57)		27	(8)
Changes in operating assets and liabilities, net of effects from purchase of subsidiaries:
Accounts receivable	(64)		(101)	(155)
Fiduciary assets	(1,167)		(249)	(508)
Fiduciary liabilities	1,167		249	508
Other assets	(128)		(233)	(5)
Other liabilities	(51)		174	(61)
Provisions	(35)		65	43
Net cash from operating activities	862		933	244
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(300)		(218)	(146)
Capitalized software costs	(75)		(85)	0
Acquisitions of operations, net of cash acquired	(13)		476	(857)
Net disposals of operations	57		(1)	44
Other, net	(4)		23	16
Net cash (used in)/from investing activities	(335)		195	(943)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	642		(237)	469
Senior notes issued	649		1,606	0
Proceeds from issuance of other debt	32		404	592
Debt issuance costs	(9)		(14)	(5)
Repayments of debt	(734)		(1,901)	(166)
Repurchase of shares	(532)		(396)	(82)
Proceeds from issuance of shares	61		63	131
Payments for share cancellation related to legal settlement	(177)		0	0
Payments of deferred and contingent consideration related to acquisitions	(65)		(67)	0
Cash paid for employee taxes on withholding shares	(18)		(13)	(1)
Dividends paid	(277)		(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	(51)		(21)	(21)
Net cash (used in)/from financing activities	(479)		(775)	640
INCREASE/(DECREASE) IN CASH AND CASH EQUIVALENTS	48		353	(59)
Effect of exchange rate changes on cash and cash equivalents	112		(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870		532	635
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 1,030		$ 870	$ 532
[1]	Depreciation expense included here does not equal the depreciation expense on the statement of comprehensive income for the year ended December 31, 2017 due to the inclusion of $49 million which has been classified as transaction and integration expenses.

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Millions		Total		Shares outstanding	Additional paid-in capital	Retained earnings	Treasury shares	AOCL	[1]	Total WTW shareholders’ equity	Non-controlling interests	Total equity
Other Comprehensive Income (Loss), Net of Tax		$ 19						$ 29		$ 29	$ (6)	$ 23
Equity, beginning balance (in shares) at Dec. 31, 2014	[2]			67,460
Equity, beginning balance at Dec. 31, 2014		2,007			$ 1,524	$ 1,530	$ (3)	(1,066)		1,985	22
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased (in shares)	[2]			(646)
Shares repurchased		(82)				(82)				(82)
Net income		384				373				373	8	381
Dividends		(235)				(224)				(224)	(11)
Issue of shares under employee stock compensation plans and related tax benefits (in shares)	[2]			1,811
Issuance of shares under employee stock compensation plans		128			128					128
Share-based compensation		64			64					64
Additional non-controlling interests		65			(53)					(53)	118
Foreign currency translation		9			9					9
Equity, ending balance (in shares) at Dec. 31, 2015	[2]			68,625
Equity, ending balance at Dec. 31, 2015		2,360			1,672	1,597	(3)	(1,037)		2,229	131
Beginning balance at Dec. 31, 2014	[3]	59
Increase (Decrease) in Temporary Equity [Roll Forward]
Temporary equity net income	[3]	3
Temporary equity dividends	[3]	(5)
Other comprehensive income/(loss)	[3]	(4)
Ending balance at Dec. 31, 2015	[3]	53
Other Comprehensive Income (Loss), Net of Tax		(867)						(847)		(847)	(16)	(863)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased (in shares)				(3,170)
Shares repurchased		(396)				(300)	(96)			(396)
Net income		438				420				420	11	431
Dividends		(274)				(265)				(265)	(9)
Issue of shares under employee stock compensation plans and related tax benefits (in shares)				1,342
Issuance of shares under employee stock compensation plans		66			66					66
Issue of shares for acquisitions (in shares)				69,500
Issue of shares for acquisitions		8,686			8,686					8,686
Replacement share-based compensation awards issued on acquisition		37			37					37
Share-based compensation		123			123					123
Additional non-controlling interests		8			7					7	1
Foreign currency translation		5			5					5
Equity, ending balance (in shares) at Dec. 31, 2016				136,297
Equity, ending balance at Dec. 31, 2016		10,183			10,596	1,452	(99)	(1,884)		10,065	118
Increase (Decrease) in Temporary Equity [Roll Forward]
Temporary equity net income	[3]	7
Temporary equity dividends	[3]	(5)
Other comprehensive income/(loss)	[3]	(4)
Ending balance at Dec. 31, 2016	[3]	51
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-16 [Member]		(3)				(3)				(3)
Other Comprehensive Income (Loss), Net of Tax		384						371		371	7	378
Shares repurchased (in shares)				(3,797)
Shares repurchased		(532)				(532)				(532)
Shares canceled, shares				(1,415)
Shares canceled		(177)			(177)	(96)	96			(177)
Net income		592				568				568	16	584
Dividends		(300)				(285)				(285)	(15)
Issue of shares under employee stock compensation plans and related tax benefits (in shares)				1,055
Issuance of shares under employee stock compensation plans		62			62					62
Share-based compensation		67			67					67
Acquisition of non-controlling interests		(34)	[3]								(3)	(3)
Foreign currency translation		(10)			(10)					(10)
Equity, ending balance (in shares) at Dec. 31, 2017				132,140
Equity, ending balance at Dec. 31, 2017		10,249			$ 10,538	$ 1,104	$ (3)	$ (1,513)		$ 10,126	123
Increase (Decrease) in Temporary Equity [Roll Forward]
Temporary equity net income	[3]	8
Temporary equity dividends	[3]	(3)
Other comprehensive income/(loss)	[3]	6
Acquisition of non-controlling interests		(34)	[3]								$ (3)	$ (3)
Ending balance at Dec. 31, 2017	[3]	$ 28
[1]	Accumulated other comprehensive loss, net of tax (‘AOCL’).
[2]	The nominal value of the ordinary shares and the number of ordinary shares issued in the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split on January 4, 2016.
[3]	The non-controlling interest is related to Max Matthiessen Holding AB.

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations Willis Towers Watson plc is a leading global advisory, broking and solutions company that helps clients around the world turn risk into a path for growth. Willis Towers Watson has more than 43,000 employees and services clients in more than 140 countries and territories. We design and deliver solutions that manage risk, optimize benefits, cultivate talent, and expand the power of capital to protect and strengthen institutions and individuals. We believe our broad perspective allows us to see the critical intersections between talent, assets and ideas - the dynamic formula that drives business performance. We offer our clients a broad range of services to help them identify and control their risks, and to enhance business performance by improving their ability to attract, retain and engage a talented workforce. Our risk control services range from strategic risk consulting (including providing actuarial analysis), to a variety of due diligence services, to the provision of practical on-site risk control services (such as health and safety or property loss control consulting), as well as analytical and advisory services (such as hazard modeling and reinsurance optimization studies). We assist clients in planning how to manage incidents or crises when they occur. These services include contingency planning, security audits and product tampering plans. We help our clients enhance their business performance by delivering consulting services, technology and solutions that help them anticipate, identify and capitalize on emerging opportunities in human capital management as well as investment advice to help our clients develop disciplined and efficient strategies to meet their investment goals. As an insurance broker, we act as an intermediary between our clients and insurance carriers by advising our clients on their risk management requirements, helping them determine the best means of managing risk and negotiating and placing insurance with insurance carriers through our global distribution network. We operate the largest private Medicare exchange in the United States (‘U.S.’). Through this exchange and those for active employees, we help our clients move to a more sustainable economic model by capping and controlling the costs associated with healthcare benefits. We are not an insurance company, and therefore we do not underwrite insurable risks for our own account. The Merger with Towers Watson that closed on January 4, 2016 affects the comparability between 2015 and the later periods presented. See Note 3 — Merger, Acquisitions and Divestitures for additional information.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements Significant Accounting Policies Principles of Consolidation — The accompanying consolidated financial statements include the accounts of Willis Towers Watson and those of our majority-owned and controlled subsidiaries. Intercompany accounts and transactions have been eliminated. We determine whether we have a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (‘VIE’). Variable interest entities are entities that lack one or more of the characteristics of a voting interest entity and therefore require a different approach in determining which party involved with the VIE should consolidate the entity. With a VIE, either the entity does not have sufficient equity at risk to finance its activities without additional subordinated financial support from other parties, or the equity holders, as a group, do not have the power to direct the activities that most significantly impact its financial performance, the obligation to absorb expected losses of the entity, or the right to receive the expected residual returns of the entity. The entity that has a controlling financial interest in a VIE is referred to as the primary beneficiary and is required to consolidate the VIE. Voting interest entities are entities that have sufficient equity and provide equity investors voting rights that give them the power to make significant decisions related to the entity’s operations. The usual condition for a controlling financial interest in a voting interest entity is ownership of a majority voting interest. Accordingly, we consolidate our voting interest entity investments in which we hold, directly or indirectly, more than 50% of the voting rights. Use of Estimates — These consolidated financial statements conform to accounting principles generally accepted in the United States of America (‘U.S. GAAP’), which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Our estimates, judgments and assumptions are continually evaluated based on available information and experience. Because of the use of estimates inherent in the financial reporting process, actual results could differ from those estimates. Estimates are used when accounting for revenue recognition, the selection of useful lives of fixed and intangible assets, impairment testing, valuation of billed and unbilled receivables from clients, discretionary compensation, income taxes, pension assumptions, incurred but not reported claims, legal reserves and goodwill and intangible assets. Going Concern — Management evaluates at each annual and interim period whether there are conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. Management’s evaluation is based on relevant conditions and events that are known and reasonably knowable at the date that the consolidated financial statements are issued. Management has concluded that there are no conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date of these financial statements. Fair Value of Financial Instruments — The carrying values of our cash and cash equivalents, accounts receivable, accrued expenses, revolving lines of credit and term loans approximate their fair values because of the short maturity and liquidity of those instruments. We consider the difference between carrying value and fair value to be immaterial for our senior notes. The fair value of our senior notes are considered Level 2 financial instruments as they are corroborated by observable market data. See Note 11 — Fair Value Measurements for additional information about our measurements of fair value. Investments in Associates — Investments are accounted for using the equity method of accounting, included within other non-current assets in the consolidated balance sheets, if the Company has the ability to exercise significant influence, but not control, over the investee. Significant influence is generally deemed to exist if the Company has an equity ownership in the voting stock of the investee between 20 and 50 percent, although other factors, such as representation on the board of directors and the impact of commercial arrangements, are considered in determining whether the equity method of accounting is appropriate. Under the equity method of accounting, the investment is carried at the cost of acquisition, plus the Company’s equity in undistributed net income since acquisition, less any dividends received since acquisition. The Company periodically reviews its investments in associates for which fair value is less than cost to determine if the decline in value is other than temporary. If the decline in value is judged to be other than temporary, the cost basis of the investment is written down to fair value. The amount of any write-down is included in the consolidated statements of comprehensive income. Common Shares Split — On January 4, 2016, the Company effected a 1 to 2.6490 reverse share split to shareholders of record as of January 4, 2016. All share and per share information has been retroactively adjusted to reflect the reverse share split and show the new number of shares. See Note 3 — Merger, Acquisitions and Divestitures for additional information about our Merger and reverse share split. Cash and Cash Equivalents — Cash and cash equivalents primarily consist of time deposits with original maturities of 90 days or less. Willis Limited, our U.K. brokerage subsidiary regulated by the Financial Conduct Authority, is currently required to maintain $140 million in unencumbered and available financial resources, of which at least $79 million must be in cash, for regulatory purposes. Term deposits and certificates of deposits with original maturities greater than 90 days are considered to be short-term investments. There is no restricted cash included in our cash and cash equivalents balance, as these amounts are included in fiduciary assets. Fiduciary Assets and Liabilities — Fiduciary funds represent unremitted premiums received from insureds and unremitted claims or refunds received from insurers. Fiduciary funds are generally required to be kept in certain regulated bank accounts subject to guidelines which emphasize capital preservation and liquidity. Such funds are not available to service the Company’s debt or for other corporate purposes. Notwithstanding the legal relationships with insureds and insurers, the Company is entitled to retain investment income earned on fiduciary funds in accordance with industry custom and practice and, in some cases, as supported by agreements with insureds. The period for which the Company holds such funds is dependent upon the date the insured remits the payment of the premium to the Company, or the date the Company receives refunds from the insurers, and the date the Company is required to forward such payment to the insurer, or insured, respectively. In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. Such advances are made from fiduciary funds and are reflected in the consolidated balance sheets as fiduciary assets. Fiduciary liabilities represent the obligations to remit fiduciary funds and fiduciary receivables to insurers or insureds. Certain of our health and welfare benefits administration outsourcing agreements require us to hold funds on behalf of clients to pay obligations on their behalf. These amounts are included in fiduciary assets and fiduciary liabilities on the consolidated balance sheets. Accounts Receivable — Accounts receivable includes both billed and unbilled receivables and is stated at estimated net realizable values. Provision for billed receivables is recorded, when necessary, in an amount considered by management to be sufficient to meet probable future losses related to uncollectible accounts. Accrued and unbilled receivables are stated at net realizable value which includes an allowance for accrued and unbillable amounts. See Note 14 — Supplementary Information for Certain Balance Sheet Accounts for additional information about our accounts receivable. Income Taxes — The Company recognizes deferred tax assets and liabilities for the estimated future tax consequences of events attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating and capital loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which the differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of changes in tax rates is recognized in the consolidated statement of comprehensive income in the period in which the change is enacted. Deferred tax assets are reduced through the establishment of a valuation allowance at such time as, based on available evidence, it is more likely than not that the deferred tax assets will not be realized. The Company adjusts valuation allowances to measure deferred tax assets at the amounts considered realizable in future periods if the Company’s facts and assumptions change. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and the results of recent financial operations. We place more reliance on evidence that is objectively verifiable. Positions taken in the Company’s tax returns may be subject to challenge by the taxing authorities upon examination. The Company recognizes the benefit of uncertain tax positions in the financial statements when it is more likely than not that the position will be sustained on the basis of the technical merits of the position assuming the tax authorities have full knowledge of the position and all relevant facts. Recognition also occurs upon either the lapse of the relevant statute of limitations, or when positions are effectively settled. The benefit recognized is the largest amount of tax benefit that is greater than 50 percent likely to be realized on settlement with the tax authority. The Company adjusts its recognition of uncertain tax benefits in the period in which new information is available impacting either the recognition or measurement of its uncertain tax positions. Such adjustments are reflected as increases or decreases to income taxes in the period in which they are determined. The Company recognizes interest and penalties relating to unrecognized tax benefits within income taxes. See Note 6 — Income Taxes for additional information regarding the Company’s income taxes. Foreign Currency — Transactions in currencies other than the functional currency of the entity are recorded at the rates of exchange prevailing at the date of the transaction. Monetary assets and liabilities in currencies other than the functional currency are translated at the rates of exchange prevailing at the balance sheet date and the related transaction gains and losses are reported as income or expense in the consolidated statements of comprehensive income. Certain intercompany loans are determined to be of a long-term investment nature. The Company records transaction gains and losses from re-measuring such loans as other comprehensive income in the consolidated statements of comprehensive income. Upon consolidation, the results of operations of subsidiaries and associates whose functional currency is other than the U.S. dollar are translated into U.S. dollars at the average exchange rates and assets and liabilities are translated at year-end exchange rates. Translation adjustments are presented as a separate component of other comprehensive income in the financial statements and are included in net income only upon sale or liquidation of the underlying foreign subsidiary or associated company. Derivatives — The Company uses derivative financial instruments for other than trading purposes to alter the risk profile of an existing underlying exposure. Interest rate swaps have been used to manage interest risk exposures. Forward foreign currency exchange contracts are used to manage currency exposures arising from future income and expenses. The fair values of derivative contracts are recorded in other assets and other liabilities. The effective portions of changes in the fair value of derivatives that qualify for hedge accounting as cash flow hedges are recorded in other comprehensive income. Amounts are reclassified from other comprehensive income into earnings when the hedged exposure affects earnings. If the derivative is designated and qualifies as an effective fair value hedge, the changes in the fair value of the derivative and of the hedged item associated with the hedged risk are both recognized in earnings. The amount of hedge ineffectiveness recognized in earnings is based on the extent to which an offset between the fair value of the derivative and hedged item is not achieved. Changes in fair value of derivatives that do not qualify for hedge accounting, together with any hedge ineffectiveness on those that do qualify, are recorded in other operating expenses or interest expense as appropriate. The Company evaluates whether its contracts include clauses or conditions which would be required to be separately accounted for at fair value as embedded derivatives. See Note 9 — Derivative Financial Instruments for additional information about the Company’s derivatives. Commitments, Contingencies and Provisions for Liabilities — The Company establishes provisions against various actual and potential claims, lawsuits and other proceedings relating principally to alleged errors and omissions in the ordinary course of business. Such provisions cover claims that have been reported but not paid and also unasserted claims and related legal fees. These provisions are established based on actuarial estimates together with individual case reviews and are believed to be adequate in light of current information and legal advice. In certain cases, where a range of loss exists, we accrue the minimum amount in the range if no amount within the range is a better estimate than any other amount. To the extent such losses can be recovered under the Company’s insurance programs, estimated recoveries are recorded when losses for insured events are recognized and the recoveries are likely to be realized. Significant management judgment is required to estimate the amounts of such unasserted claims and the related insurance recoveries. The Company analyzes its litigation exposure based on available information, including consultation with outside counsel handling the defense of these matters, to assess its potential liability. These contingent liabilities are not discounted. See Note 13 — Commitments and Contingencies and Note 14 — Supplementary Information for Certain Balance Sheet Accounts for additional information about our commitments, contingencies and provisions for liabilities. Share-Based Compensation — The Company has equity-based compensation plans that provide for grants of restricted stock units and stock options to employees and non-employee directors of the Company. The Company expenses equity-based compensation, which is included in Salaries and benefits in the consolidated statements of comprehensive income, primarily on a straight-line basis over the requisite service period. The significant assumptions underlying our expense calculations include the fair value of the award on the date of grant, the estimated achievement of any performance targets and estimated forfeiture rates. The awards under equity-based compensation are classified as equity and included as a component of equity on the Company’s consolidated balance sheets, as the ultimate payment of such awards will not be achieved through use of the Company’s cash or other assets. See Note 17 — Share-based Compensation for additional information about the Company’s share-based compensation. Fixed Assets — Fixed assets are stated at cost less accumulated depreciation. Expenditures for improvements are capitalized; repairs and maintenance are charged to expense as incurred. Depreciation is computed primarily using the straight-line method based on the estimated useful lives of assets. Depreciation on internally developed software is amortized over the estimated useful life of the asset ranging from 3 to 10 years. Buildings include assets held under capital leases and are depreciated over the lesser of 50 years, the asset lives or the lease terms. Depreciation on leasehold improvements is calculated over the lesser of the useful lives of the assets or the remaining lease terms. Depreciation on furniture and equipment is calculated based on a range of 3 to 10 years. Land is not depreciated. Long-lived assets are tested for recoverability whenever events or changes in circumstance indicate that their carrying amounts may not be recoverable. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. Recoverability is determined based on the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group. Long-lived assets and certain identifiable intangible assets to be disposed of are reported at the lower of carrying amount or fair value less cost to sell. See Note 7 — Fixed Assets for additional information about our fixed assets. Operating Leases —Rentals payable on operating leases are charged on a straight-line basis to Other operating expenses in the consolidated statements of comprehensive income over the lease term. See Note 13 — Commitments and Contingencies for additional information about our operating leases. Goodwill and Other Intangible Assets — In applying the acquisition method of accounting for business combinations, amounts assigned to identifiable assets and liabilities acquired were based on estimated fair values as of the date of acquisition, with the remainder recorded as goodwill. Intangible assets are initially valued at fair value using generally accepted valuation methods appropriate for the type of intangible asset. Intangible assets with definite lives are amortized over their estimated useful lives and are reviewed for impairment if indicators of impairment arise. Intangible assets with indefinite lives are tested for impairment annually as of October 1, and whenever indicators of impairment exist. The fair values of intangible assets are compared with their carrying values, and an impairment loss would be recognized for the amount by which a carrying amount exceeds its fair value. Acquired intangible assets are amortized over the following periods: Amortization basis Expected life (years) Client relationships In line with underlying cash flows 5 to 20 Software In line with underlying cash flows or straight-line basis 4 to 7 Product In line with underlying cash flows 17.5 Trademark and trade name Straight-line basis 14 to 25 Favorable agreements Straight-line basis 7 Management contracts Straight-line basis 18 Goodwill is tested for impairment annually as of October 1, and whenever indicators of impairment exist. Goodwill is tested at the reporting unit level, and the Company had nine reporting units as of October 1, 2017. In the first step of the impairment test, the fair value of each reporting unit is compared with its carrying value, including goodwill. If the carrying value of a reporting unit exceeds its fair value, the amount of an impairment loss, if any, is calculated in the second step of the impairment test by comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. The Company’s goodwill impairment tests for the years ended December 31, 2017 and 2016 have not resulted in any impairment charges. See Note 8 — Goodwill and Other Intangible Assets for additional information about our goodwill and other intangible assets. Pensions — The Company has multiple defined benefit pension and defined contribution plans. The net periodic cost of the Company’s defined benefit plans are measured on an actuarial basis using various methods and actuarial assumptions. The most significant assumptions are the discount rates (calculated from the 2016 fiscal year and forward using the granular approach to calculating service and interest cost) and the expected long-term rates of return on plan assets. Other material assumptions include rates of participant mortality, the expected long-term rates of compensation and pension increases and rates of employee termination. Gains and losses occur when actual experience differs from actuarial assumptions. If such gains or losses exceed ten percent of the greater of plan assets or plan liabilities, the Company amortizes those gains or losses over the average remaining service period or average remaining life expectancy, as appropriate, of the plan participan ts. In accordance with U.S. GAAP, the Company records on its consolidated balance sheets the funded status of its pension plans based on the projected benefit obligation. Contributions to the Company’s defined contribution plans are recognized as incurred. Differences between contributions payable in the year and contributions actually paid are shown as either other assets or other liabilities in the consolidated balance sheets. See Note 12 — Retirement Benefits for additional information about our pensions. Revenue Recognition — Revenues include insurance commissions, fees in lieu of commission, fees for consulting services rendered, hosted and delivered software, survey sales, interest and other income. Revenue recognized in excess of billings is recorded as unbilled accounts receivable. Cash collections in excess of revenue recognized are recorded as deferred revenue until the revenue recognition criteria are met. Client reimbursable expenses, including those relating to travel, other out-of-pocket expenses and any third-party costs, are included in revenue, and an equivalent amount of reimbursable expenses is included in other operating expenses as a cost of revenue. Taxes collected from customers and remitted to government authorities are recorded net and are excluded from revenue. Commissions and fees Commissions revenue. Brokerage commissions and fees negotiated in lieu of commissions are recognized at the later of the policy inception date or when the policy placement is complete. In situations in which our fees are not fixed and determinable due to the uncertainty of the commission fee per policy, we recognize revenue as the fees are determined. Commissions on additional premiums and adjustments are recognized when approved by or agreed between the parties and collectability is reasonably assured. Consulting revenue. The majority of our consulting revenues consists of fees earned from providing consulting services. We recognize revenues from these consulting engagements when hours are worked, either on a time-and-expense basis or on a fixed-fee basis, depending on the terms and conditions defined at the inception of an engagement with a client. We have engagement letters with our clients that specify the terms and conditions upon which the engagements are based. These terms and conditions can only be changed upon agreement by both parties. Individual billing rates are principally based on a multiple of salary and compensation costs. Revenues for fixed-fee arrangements are based upon the proportional performance method to the extent estimates can be made of the remaining work required under the arrangement. If we do not have sufficient information to estimate proportional performance, we recognize the fees straight-line over the contract period. We typically have four types of fixed-fee arrangements: annual recurring projects, projects of a short duration, stand-ready obligations and non-recurring system projects. • Annual recurring projects and projects of short duration. These projects are typically straightforward and highly predictable in nature. As a result, the project manager and financial staff are able to identify, as the project status is reviewed and bills are prepared monthly, the occasions when cost overruns could lead to the recording of a loss accrual. • Stand-ready obligations. Where we are entitled to fees (whether fixed or variable based on assets under management or a per-participant per-month basis) regardless of the hours, we generally recognize this revenue on either a straight-line basis or as the variable fees are calculated. • Non-recurring system projects. These projects are longer in duration and subject to more changes in scope as the project progresses. Certain software or outsourced administration contracts generally provide that if the client terminates a contract, we are entitled to an additional payment for services performed through termination designed to recover our up-front cost of implementation. Revenue recognition for fixed-fee engagements is affected by a number of factors that change the estimated amount of work required to complete the project such as changes in scope, the staffing on the engagement and/or the level of client participation. The periodic engagement evaluations require us to make judgments and estimates regarding the overall profitability and stage of project completion that, in turn, affect how we recognize revenue. We recognize a loss on an engagement when estimated revenues to be received for that engagement are less than the total estimated costs associated with the engagement. Losses are recognized in the period in which the loss becomes probable and the amount of the loss is reasonably estimable. Hosted software. We have developed various software programs and technologies that we provide to clients in connection with consulting services. In most instances, such software is hosted and maintained by us and ownership of the technology and rights to the related code remain with us. We defer costs for software developed to be utilized in providing services to a client, but for which the client does not have the contractual right to take possession, during the implementation stage. We recognize these deferred costs from the go live date, signaling the end of the implementation stage, until the end of the initial term of the contract with the client. We determined that the system implementation and customized ongoing administrative services are one combined service. Revenue is recognized over the service period, after the go live date, on a straight-line basis. As a result, we do not recognize revenue during the implementation phase of an engagement. Delivered software. We deliver software under arrangements with clients who take possession of our software. The maintenance associated with the initial software fees is a fixed percentage which enables us to determine the stand-alone value of the delivered software separate from the maintenance. We recognize the initial software fees as software is delivered to the client, and we recognize the maintenance fees ratably over the contract period based on each element’s relative fair value. For software arrangements in which initial fees are received in connection with mandatory maintenance for the initial software license to remain active, we determined that the initial maintenance period is substantive. Therefore, we recognize the fees for the initial license and maintenance bundle ratably over the initial contract term, which is generally one year . Each subsequent renewal fee is recognized ratably over the contractually stated renewal period. Surveys. We collect, analyze and compile data in the form of surveys for our clients who have the option of participating in the survey. The surveys are published online via a web tool that provides simplistic functionality. We have determined that the web tool is inconsequential to the overall arrangement. We record the survey revenues when the results are delivered online and made available to our clients who have a contractual right to the data. If the data is updated more frequently than annually, we recognize the survey revenues ratably over the contractually stated period. Interest and other income Interest income. Interest income is recognized as earned. Other Income. Other income includes gains on disposal of intangible assets, which primarily arise from settlements through enforcing non-compete agreements in the event of losing accounts through producer defection or the disposal of books of business. Recent Accounting Pronouncements Not yet adopted In May 2014, the Financial Accounting Standards Board (‘FASB’) issued Accounting Standard Update (‘ASU’) No. 2014-09, Revenue From Contracts With Customers . The new standard supersedes most current revenue recognition guidance and eliminates most industry-specific guidance. The ASU is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. Additional ASUs have since been issued which provide further guidance, examples and technical corrections for the implementation of ASU No. 2014-09. All related guidance has been codified into, and is now known as, Accounting Standards Codification (‘ASC’) 606. The guidance was effective for the Company at the beginning of its 2018 fiscal year, with early adoption permitted. As a result of analyzing our various revenue streams to determine the full impact this standard will have on our revenue recognition, cost deferral, systems and processes, the Company has determined the following: • The Company has adopted the standard using the modified retrospective approach on January 1, 2018, and has applied the new standard only to contracts that are not completed as of the transition date. • Certain revenue streams have accelerated revenue recognition timing. In particular, the revenue recognition for our Individual Marketplace (formerly Retiree & Access Exchanges) has moved from monthly ratable recognition over the policy period, to the recognition upon placement of the policy. Consequently, the Company will now recognize the majority of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. Therefore, at the adoption date, we have reflected an adjustment to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, the revenue recognition for proportional treaty broking commissions has moved from recognition upon the receipt of the monthly or quarterly statements, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we will reflect an adjustment to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior. • Revenue recognition for certain other revenue streams has changed from recognizing revenue at a point in time to recognizing revenue over time. Specifically, certain arrangements in our Health and Benefits broking business will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or an

Merger, Acquisitions and Divest

Merger, Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Merger and Acquisitions	Merger, Acquisitions and Divestitures Merger On January 4, 2016, pursuant to the Agreement and Plan of Merger, dated June 29, 2015, as amended on November 19, 2015, between Willis, Towers Watson, and Citadel Merger Sub, Inc., a wholly-owned subsidiary of Willis formed for the purpose of facilitating this transaction (‘Merger Sub’), Merger Sub merged with and into Towers Watson, with Towers Watson continuing as the surviving corporation and as a wholly-owned subsidiary of Willis. Towers Watson was a leading global professional services firm operating throughout the world, dating back more than 100 years . The Merger allows the combined firm to go to market with complementary strategic product and services offerings. At the effective time of the Merger (the ‘Effective Time’), each issued and outstanding share of Towers Watson common stock (the ‘Towers Watson shares’), was converted into the right to receive 2.6490 validly issued, fully paid and nonassessable ordinary shares of Willis (the ‘Willis ordinary shares’), $0.000115 nominal value per share, other than any Towers Watson shares owned by Towers Watson, Willis or Merger Sub at the Effective Time and the Towers Watson shares held by stockholders who are entitled to and who properly exercised dissenter’s rights under Delaware law. Immediately following the Merger, Willis effected (i) a consolidation (i.e., a reverse stock split under Irish law) of Willis ordinary shares whereby every 2.6490 Willis ordinary shares were consolidated into one Willis ordinary share ( $0.000304635 nominal value per share) and (ii) an amendment to its constitution and other organizational documents to change its name from Willis Group Holdings Public Limited Company to Willis Towers Watson Public Limited Company. On December 29, 2015, the third business day immediately prior to the closing date of the Merger, Towers Watson declared and paid a pre-merger special dividend of $10.00 per share of its common stock, and approximately $694 million in the aggregate based on approximately 69 million Towers Watson shares issued and outstanding at December 29, 2015. On December 30, 2015, all Towers Watson treasury stock was canceled. The Merger was accounted for using the acquisition method of accounting, with Willis considered the accounting acquirer of Towers Watson. The table below presents the final calculation of aggregate Merger consideration . January 4, 2016 Number of shares of Towers Watson common stock outstanding as of January 4, 2016 69 million Exchange ratio 2.6490 Number of Willis Group Holdings shares issued (prior to reverse stock split) 184 million Willis Group Holdings price per share on January 4, 2016 $ 47.18 Fair value of 184 million Willis ordinary shares $ 8,686 Value of equity awards assumed 37 Aggregate Merger consideration $ 8,723 A summary of the fair values of the identifiable assets acquired, and liabilities assumed, of Towers Watson at January 4, 2016 are summarized in the following table. January 4, 2016 Cash and cash equivalents $ 476 Accounts receivable, net 825 Other current assets 82 Fixed assets, net 204 Goodwill 6,783 Intangible assets 3,991 Pension benefits assets 67 Other non-current assets 115 Deferred tax liabilities (1,151 ) Liability for pension benefits (923 ) Other current liabilities (i) (667 ) Other non-current liabilities (ii) (331 ) Long term debt, including current portion (iii) (740 ) Net assets acquired 8,731 Non-controlling interests acquired (8 ) Allocated aggregate Merger consideration $ 8,723 ____________________ (i) Includes $348 million in accounts payable, accrued liabilities and deferred revenue, $308 million in employee-related liabilities and $11 million in other current liabilities. (ii) Includes acquired contingent liabilities of $ 242 million . See Note 13 — Commitments and Contingencies for a discussion of our material acquired contingencies related to Legacy Towers Watson. (iii) Represents both debt due upon change of control of $400 million borrowed under Towers Watson’s term loan ( $188 million ) and revolving credit facility ( $212 million ) and a draw down under a new term loan of $340 million . The $400 million debt was repaid by Willis’ borrowings under the 1-year term loan facility on January 4, 2016. The $340 million new term loan partially funded the $694 million Towers Watson pre-merger special dividend. The purchase price allocation as of the date of acquisition was based on a valuation of the assets acquired and liabilities assumed in the acquisition. The purchase price allocation was complete as of December 31, 2016. Goodwill was calculated as the difference between the aggregate Merger consideration and the acquisition date fair value of the net assets acquired, and represents the value of the Legacy Towers Watson assembled workforce and the future economic benefits that we expect to realize as a result of the Merger. None of the goodwill recognized on the transaction is tax deductible. The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 2,221 15.0 Software - income approach Multiple period excess earnings In line with underlying cash flows or straight-line basis 567 6.4 Software - cost approach Cost of reproduction Straight-line basis 108 4.9 Product Multiple period excess earnings In line with underlying cash flows 42 17.5 IPR&D (i) Multiple period excess earnings or cost of reproduction n/a 39 n/a Trade name Relief from royalty Straight-line basis 1,003 25.0 Favorable lease agreements Market approach Straight-line basis 11 6.5 $ 3,991 ____________________ (i) Represents individual in-process research and development (‘IPR&D’) software components not placed into service as of the acquisition date. These assets were subsequently placed into service during the three months ended March 31, 2017, were reclassified into finite-lived software intangible assets, and are being amortized in line with underlying cash flows or on a straight-line basis. The following pro forma financial information is unaudited and is intended to reflect the impact of the Merger on Willis Towers Watson’s consolidated financial statements as if the Merger had taken place on January 1, 2015 and presents the results of operations of Willis Towers Watson based on the historical financial statements of Willis and Towers Watson after giving effect to the Merger and pro forma adjustments. Pro forma adjustments are included only to the extent they are (i) directly attributable to the Merger, (ii) factually supportable and (iii) with respect to the consolidated statement of comprehensive income, expected to have a continuing impact on the combined results. The accompanying unaudited pro forma financial information is presented for illustrative purposes only and has not been adjusted to give effect to certain expected financial benefits of the Merger, such as revenue synergies, tax savings and cost synergies, or the anticipated costs to achieve these benefits, including the cost of integration activities. The unaudited pro forma results are not indicative of what would have occurred had the Merger taken place on the indicated date. Years ended December 31, Pro Forma As reported (Unaudited) 2016 2015 Total revenues $ 7,887 $ 7,492 Net income attributable to Willis Towers Watson $ 420 $ 640 Diluted earnings per share $ 3.04 $ 4.64 The above pro forma financial information for the year ended December 31, 2015 does not include pro forma adjustments for the Gras Savoye or other acquisitions as their revenues and results of operations were immaterial to the consolidated financial statements. Revenues attributable to Towers Watson for the year ended December 31, 2016 were $3.6 billion . Net income attributable to Towers Watson for the year ended December 31, 2016 was $111 million . Acquired Share-Based Compensation Plans In connection with the Merger , we assumed certain stock options and restricted stock units (‘RSUs’) issued under the Towers Watson & Co. 2009 Long Term Incentive Plan (‘LTIP’), the Liazon Corporation 2011 Equity Incentive Plan, and the Extend Health, Inc. 2007 Equity Incentive Plan. Stock Options. The outstanding unvested employee stock options were converted into 592,486 Willis Towers Watson stock options using the conversion ratios stated in the Merger agreement for the number of options. The fair value of the stock options was calculated using the Black-Scholes model with a volatility and risk-free interest rate over the expected term of each group of options and Willis Towers Watson’s closing share price on the date of acquisition. We determined the fair value of the portion of the outstanding options related to pre-acquisition employee service using the straight-line expense methodology from the date of grant to the acquisition date to be $7 million , which was added to the transaction consideration. The fair value of the remaining portion of options related to the post-acquisition employee services was $13 million , and will be recognized over the future vesting periods. Restricted Stock Units. The outstanding unvested RSUs were converted into 597,307 Willis Towers Watson RSUs using the conversion ratios as stated in the Merger agreement. The fair value of these RSUs was calculated using Willis Towers Watson’s closing share price on the date of acquisition. We determined the fair value of the portion of the outstanding RSUs related to pre-acquisition employee service using the straight-line expense methodology from the date of grant to the acquisition date to be $30 million , which was added to the transaction consideration. The fair value of the remaining portion of RSUs related to the post-acquisition employee services was $32 million , and will be recognized over the future vesting periods. Gras Savoye Acquisition On December 29, 2015, Legacy Willis completed the transaction to acquire substantially all of the remaining 70% of the outstanding share capital of Gras Savoye, the leading insurance broker in France, for total consideration of €544 million ( $592 million ) of which $582 million in cash was paid at closing. Additionally, the previously held equity interest in Gras Savoye was re-measured to a fair value of €221 million ( $241 million ) giving a total fair value on a 100% basis of €765 million ( $833 million ). The union combines the Company’s global insurance broking footprint with Gras Savoye’s particularly strong presence in France, Central and Eastern Europe, and across Africa. Gras Savoye’s expertise in high-growth markets and industry sectors complements the Company’s global strengths, creating value for clients. The Company funded the cash consideration with a 1 -year term loan. The term loan was repaid in its entirety on May 26, 2016, from the proceeds from the issuance of new senior notes discussed in Note 10 — Debt to these consolidated financial statements. Deferred consideration is payable on the first and second anniversary of the acquisition. In December 2017, the Company made final consideration payments of $3 million . The discounted fair value of the deferred consideration at December 31, 2016 was $4 million . None of the goodwill recognized on the transaction is tax deductible. The following table presents the Company’s allocation of the purchase price to the assets acquired and liabilities assumed based on their fair values: December 29, 2015 Cash and cash equivalents $ 87 Fiduciary assets 625 Accounts receivable, net 89 Goodwill 584 Intangible assets 440 Other assets 56 Fiduciary liabilities (625 ) Deferred revenue and accrued expenses (80 ) Short and long-term debt (80 ) Net deferred tax liabilities (87 ) Other liabilities (179 ) Net assets acquired 830 Decrease in paid-in capital for purchase of non-controlling interest 43 Non-controlling interest acquired (40 ) Purchase price allocation $ 833 The purchase price allocation as of the date of acquisition was based on a valuation and was subject to revision within the purchase price allocation period as more detailed analysis was completed and additional information about the value of assets acquired and liabilities assumed became available. During the year ended December 31, 2016 , the assessment outlined above was updated to reflect the final estimates of the fair value of assets and liabilities acquired. The purchase price allocation is final. The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 339 20 Software and other intangibles Cost of reproduction Straight-line basis 66 5 Trade name Relief from royalty Straight-line basis 35 14 $ 440 Miller Insurance Services LLP Acquisition On May 31, 2015, Legacy Willis completed the transaction to acquire an 85 percent interest in Miller, a leading London wholesale specialist insurance broking firm, for total consideration of $401 million , including cash consideration of $232 million . Deferred consideration is payable at the first, second and third anniversaries of the acquisition. Contingent consideration is payable at the third anniversary of the acquisition and is contingent on meeting certain earnings before interest, taxes, depreciation and amortization (‘EBITDA’) performance targets. At December 31, 2017, the discounted fair values of the deferred consideration related to the third anniversary and contingent consideration were $38 million and $40 million , respectively. At December 31, 2016, the discounted fair values of the deferred consideration related to the second and third anniversaries and contingent consideration were $69 million and $26 million , respectively. The Company recognized assets and liabilities acquired of $1.1 billion and $844 million , respectively. Included within the acquired assets are identifiable intangible assets of $231 million and goodwill of $184 million . The purchase price allocation as of the date of acquisition was based on a valuation of the assets acquired, liabilities assumed, and contingent consideration associated with the acquisition. There were no material revisions to the purchase price allocation during the year ended December 31, 2016 , as the purchase price allocation is final. Divestitures Related Party Transaction - In the third quarter of 2017, the Company divested its Global Wealth Solutions business through a sale to an employee of the business. As part of that transaction, we financed a $50 million note payable from the employee to purchase the business. The note amortizes over 10 years, bears interest at a weighted-average rate of 3% and is guaranteed by $3 million in assets. Following the sale, employees of this business are no longer employees of the Company, and the purchasing employee is no longer considered a related party. The current and non-current portions of the note receivable are included in the tables found in Note 14 — Supplementary Information for Certain Balance Sheet Accounts to these consolidated financial statements as Other current assets and Other non-current assets. Cumulative Divestiture Impact - Including the divestiture of Global Wealth Solutions, we sold five businesses during the second half of 2017. For the year ended December, 31, 2017, the total gain recognized related to business disposals was $13 million , which was recorded in Other expense/(income), net on the accompanying consolidated statements of comprehensive income. Results from these disposals prior to the sales represented $54 million of revenue and $13 million of operating income for the year ended December 31, 2017.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information Willis Towers Watson has four reportable operating segments or business areas: • Human Capital and Benefits (‘HCB’) • Corporate Risk and Broking (‘CRB’) • Investment, Risk and Reinsurance (‘IRR’) • Benefits Delivery and Administration (‘BDA’) - formerly known as Exchange Solutions (i) ____________________ (i) This segment and the businesses within the segment were renamed to better reflect the nature of the services we offer. Willis Towers Watson’s chief operating decision maker is its chief executive officer. We determined that the operational data used by the chief operating decision maker is at the segment level. Management bases strategic goals and decisions on these segments and the data presented below is used to assess the adequacy of strategic decisions, the method of achieving these strategies and related financial results. Management evaluates the performance of its segments and allocates resources to them based on net operating income on a pre-bonus, pre-tax basis. Beginning in 2017, we made certain changes that affect our segment results. These changes, which are detailed in the Form 8-K filed with the SEC on April 7, 2017, include the following: • First, to better align our business within our segments, we moved Max Matthiessen, which specializes in pension investment advice, to Investment, Risk and Reinsurance from Human Capital and Benefits; and moved Fine Art, Jewellery and Specie, which is a specialty broker, to Corporate Risk and Broking from Investment, Risk and Reinsurance. • Second, we recast operating income to better reflect the new segment reporting basis. As part of the further integration of our Willis Towers Watson businesses, we updated our corporate expense allocations to standardize our methodologies and allocate those expenses which are directly related to the business segment operations. Additionally, we revised the presentation of certain adjustments which arose from the purchase accounting for the Merger. Due to the long-term nature of these adjustments, which impact fixed assets and internally-developed software, we aligned the presentation within the respective segments and consolidated operating income, thereby eliminating a reconciling adjustment. The prior period comparatives reflected in the tables below have been retroactively adjusted to reflect our current segment presentation. Under the segment structure and for internal and segment reporting, Willis Towers Watson segment revenues include commissions and fees, interest and other income. U.S. GAAP revenues include amounts that were directly incurred on behalf of our clients and reimbursed by them (reimbursable expenses), which are removed from segment revenues. Segment commissions and fees excludes interest and other income. Segment operating income excludes certain costs, including (i) amortization of intangibles; (ii) restructuring costs; (iii) certain transaction and integration expenses; (iv) certain litigation provisions; (v) significant pension settlement and curtailment gains or losses; and (vi) to the extent that the actual expense based upon which allocations are made differs from the forecast/budget amount, a reconciling item will be created between internally allocated expenses and the actual expense that we report for U.S. GAAP purposes. During 2016, segment revenues and operating income both include revenue that was deferred by Towers Watson at the time of the Merger, and eliminated due to purchase accounting. The impact of the elimination from purchase accounting (which is the reduction to 2016 consolidated revenues and operating income) has been included in the reconciliation to our consolidated results in order to provide the actual revenues that the segments would have recognized on an unadjusted basis. The Company experiences seasonal fluctuations of its commissions and fees revenue. Revenue is typically higher during the Company’s first and fourth quarters due to the timing of broking-related activities. The table below presents segment commissions and fees, segment interest and other income, segment revenues, and segment operating income for our reportable segments for the years ended December 31, 2017, 2016, and 2015 . Years ended December 31, HCB CRB IRR BDA Total 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Segment commissions and fees $ 3,163 $ 3,100 $ 583 $ 2,625 $ 2,519 $ 2,332 $ 1,505 $ 1,475 $ 895 $ 729 $ 652 $ — $ 8,022 $ 7,746 $ 3,810 Segment interest and other income 29 17 1 23 28 17 30 59 1 — 2 — 82 106 19 Segment revenues $ 3,192 $ 3,117 $ 584 $ 2,648 $ 2,547 $ 2,349 $ 1,535 $ 1,534 $ 896 $ 729 $ 654 $ — $ 8,104 $ 7,852 $ 3,829 Segment operating income $ 781 $ 728 $ 119 $ 488 $ 463 $ 457 $ 365 $ 383 $ 207 $ 152 $ 119 $ — $ 1,786 $ 1,693 $ 783 The table below presents a reconciliation of the information reported by segment to the consolidated amounts reported for the years ended December 31, 2017, 2016, and 2015 , respectively: Years ended December 31, 2017 2016 2015 Revenues: Total segment revenues $ 8,104 $ 7,852 $ 3,829 Fair value adjustment to deferred revenue — (58 ) — Reimbursable expenses and other 98 93 — Total revenues $ 8,202 $ 7,887 $ 3,829 Total segment operating income $ 1,786 $ 1,693 $ 783 Fair value adjustment for deferred revenue — (58 ) — Amortization (581 ) (591 ) (76 ) Restructuring costs (132 ) (193 ) (126 ) Transaction and integration expenses (i) (269 ) (177 ) (73 ) Provision for Stanford and other significant litigation (11 ) (50 ) (70 ) Pension settlement and curtailment gains and losses (36 ) — — Unallocated, net (ii) (19 ) (73 ) (11 ) Income from operations 738 551 427 Interest expense 188 184 142 Other expense/(income), net 61 27 (55 ) Income from operations before income taxes and interest in earnings of associates $ 489 $ 340 $ 340 ____________________ (i) Includes transaction and integration expenses related to the Merger and the acquisition of Gras Savoye. (ii) Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes. The Company does not currently provide asset information by reportable segment as it does not routinely evaluate the total asset position by segment. None of the Company’s customers represented a significant amount of the Company’s consolidated commissions and fees for the years ended December 31, 2017 , 2016 and 2015 . Below are our revenues and long-lived assets for Ireland, our country of domicile, countries with significant concentrations, and all other foreign countries for each of the years ended December 31, 2017 , 2016 and 2015 : Revenues Long-Lived Assets (i) 2017 2016 2015 2017 2016 2015 Ireland $ 107 $ 92 $ 64 $ 127 $ 114 $ 124 United States 3,821 3,395 1,597 9,988 11,400 1,759 United Kingdom 1,815 2,236 1,055 3,173 2,431 2,426 Rest of World 2,459 2,164 1,113 3,263 2,466 1,951 Total Foreign Countries 8,095 7,795 3,765 16,424 16,297 6,136 $ 8,202 $ 7,887 $ 3,829 $ 16,551 $ 16,411 $ 6,260 ____________________ (i) Long-Lived Assets do not include deferred tax assets.

Restructuring Costs

Restructuring Costs	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring Costs	Restructuring Costs The Company has two major elements of the restructuring costs included in its consolidated financial statements, which are the Operational Improvement Program, completed as of the end of 2017, and the Business Restructure Program, which was fully accrued and completed by the end of 2016. Operational Improvement Program - In April 2014, Legacy Willis announced a multi-year operational improvement program designed to strengthen its client service capabilities and to deliver future cost savings. The main elements of the program, which were completed by the end of 2017, included: moving more than 3,500 support roles from higher cost locations to facilities in lower cost locations; net workforce reductions in support positions; lease consolidation in real estate; and information technology systems simplification and rationalization. The Company recognized restructuring costs of $ 134 million , $145 million , and $126 million for the years ended December 31, 2017, 2016, and 2015 , respectively, related to the Operational Improvement Program. The Company has spent a cumulative amount of $441 million on restructuring charges for this program. Business Restructure Program - In the second quarter of 2016, we began planning targeted staffing reductions in certain portions of the business due to a reduction in business demand or change in business focus (hereinafter referred to as the Business Restructure Program). The main element of the program included workforce reductions, and was completed in 2016. During the year ended December 31, 2017, the Company recognized a $2 million reversal of expense related to an estimate of previously incurred termination benefits. The Company recognized restructuring costs of $48 million for the year ended December 31, 2016 . An analysis of total restructuring costs recognized in the consolidated statements of comprehensive income, and the costs by segment, and costs attributable to corporate functions, for the years ended December 31, 2017 , 2016 and 2015 are as follows: HCB CRB IRR BDA Corporate Total Year ended December 31, 2017 Termination benefits $ — $ 25 $ 4 $ — $ 17 $ 46 Professional services and other (i) 3 63 6 — 14 86 Total $ 3 $ 88 $ 10 $ — $ 31 $ 132 Year ended December 31, 2016 Termination benefits $ 33 $ 26 $ 6 $ 1 $ 2 $ 68 Professional services and other (i) 4 81 4 — 36 125 Total $ 37 $ 107 $ 10 $ 1 $ 38 $ 193 Year ended December 31, 2015 Termination benefits $ 2 $ 24 $ 7 $ — $ 3 $ 36 Professional services and other (i) 1 57 2 — 30 90 Total $ 3 $ 81 $ 9 $ — $ 33 $ 126 ___________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs. An analysis of the total cumulative restructuring costs recognized for the Operational Improvement Program from its commencement to December 31, 2017 by segment is as follows: HCB CRB IRR BDA Corporate Total 2014 Termination benefits $ — $ 15 $ 1 $ — $ — $ 16 Professional services and other (i) — 3 — — 17 20 2015 Termination benefits $ 2 $ 24 $ 7 $ — $ 3 $ 36 Professional services and other (i) 1 57 2 — 30 90 2016 Termination benefits $ 1 $ 18 $ 3 $ — $ 1 $ 23 Professional services and other (i) 1 81 4 — 36 122 2017 Termination benefits $ — $ 25 $ 4 $ — $ 19 $ 48 Professional services and other (i) 3 63 6 — 14 86 Total Termination benefits $ 3 $ 82 $ 15 $ — $ 23 $ 123 Professional services and other (i) 5 204 12 — 97 318 Total $ 8 $ 286 $ 27 $ — $ 120 $ 441 ____________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program. The changes in the Company’s liability under the Operational Improvement Program from its commencement to December 31, 2017 , are as follows: Termination Benefits Professional Services and Other Total Balance at January 1, 2014 $ — $ — $ — Charges incurred 16 20 36 Cash payments (11 ) (14 ) (25 ) Balance at December 31, 2014 5 6 11 Charges incurred 36 90 126 Cash payments (26 ) (85 ) (111 ) Balance at December 31, 2015 15 11 26 Charges incurred 23 122 145 Cash payments (31 ) (115 ) (146 ) Balance at December 31, 2016 7 18 25 Charges incurred 48 86 134 Cash payments (41 ) (97 ) (138 ) Balance at December 31, 2017 $ 14 $ 7 $ 21 Restructuring costs related to the Business Restructuring Program for the year ended December 31, 2016 by segment are as follows: HCB CRB IRR BDA Corporate Total (in millions) 2016 Termination benefits $ 32 $ 8 $ 3 $ 1 $ 1 $ 45 Professional services and other (i) 3 — — — — 3 Total $ 35 $ 8 $ 3 $ 1 $ 1 $ 48 ____________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program. The changes in the Company’s liability under the Business Restructure Program from its commencement to December 31, 2017 , are as follows: Termination Benefits Professional Services and Other Total Balance at January 1, 2016 $ — $ — $ — Charges incurred 45 3 48 Cash payments (19 ) (3 ) (22 ) Balance at December 31, 2016 $ 26 $ — $ 26 Adjustment to prior charges incurred (2 ) — (2 ) Cash payments (23 ) — (23 ) Balance at December 31, 2017 $ 1 $ — $ 1

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Impact of U.S. Tax Reform On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (hereafter ‘U.S. Tax Reform’). U.S. Tax Reform makes broad and complex changes to the U.S. tax code, including, but not limited to: (1) requiring a one-time transition tax on certain unremitted earnings of foreign subsidiaries that may be payable over eight years; (2) bonus depreciation that will allow for a full expensing of qualified property; (3) reduction of the federal corporate tax rate from 35% to 21% ; (4) a new provision designed to tax global intangible low-taxed income (‘GILTI’), which allows for the possibility of using foreign tax credits (‘FTCs’) and a deduction of up to 50% to offset the income tax liability (subject to some limitations); (5) a new limitation on deductible interest expense; (6) limitations on the deductibility of certain executive compensation; (7) limitations on the use of FTCs to reduce the U.S. income tax liability; (8) the creation of the base erosion anti-abuse tax (‘BEAT’), a new minimum tax; and (9) a general elimination of U.S. federal income taxes on dividends from foreign subsidiaries. Also on December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (‘SAB 118’), which provides guidance on accounting for the tax effects of the U.S. Tax Reform. SAB 118 provides for a measurement period that should not extend beyond one year from the U.S. Tax Reform enactment date for companies to complete the accounting under ASC 740, Income Taxes (‘ASC 740’). In accordance with SAB 118, a company must reflect the income tax effects of those aspects of U.S. Tax Reform for which the accounting under ASC 740 is complete. Adjustments to incomplete and unknown amounts will be recorded and disclosed prospectively during the measurement period. To the extent that a company’s accounting for certain income tax effects of U.S. Tax Reform is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of U.S. Tax Reform. At December 31, 2017, there are no material elements of U.S. Tax Reform for which the Company’s accounting is complete. While the Company's accounting for the following elements of U.S. Tax Reform is incomplete, the Company was able to make reasonable estimates of certain effects. Accordingly, the Company recorded provisional adjustments for the following significant items: Reduction of the federal corporate tax rate – Beginning January 1, 2018, the Company’s U.S. income will be taxed at a 21% federal corporate tax rate. Under ASC 740, deferred tax assets and liabilities must be recalculated as of the enactment date using current tax laws and rates expected to be in effect when the deferred tax items reverse in future periods, which is 21% . Consequently, the Company has recorded a provisional decrease in its net deferred tax liabilities of $208 million , with a corresponding deferred income tax benefit of $208 million . While the Company is able to make a reasonable estimate of the impact of the reduction in the federal corporate tax rate, it may be affected by other analyses related to U.S. Tax Reform that could result in other adjustments to U.S. federal deferred tax balances, including analysis of tax amounts in other comprehensive income and any future guidance issued. One-time transition tax – The one-time transition tax is based on the Company’s total post-1986 earnings and profits (‘E&P’) that it previously deferred from U.S. income taxes. The Company recorded a provisional amount for the one-time transition tax liability for its foreign subsidiaries owned by U.S. corporate shareholders, resulting in an increase in U.S. Federal income tax expense of $70 million and state income tax expense of $2 million . The Company has a significant number of foreign subsidiaries and therefore has not yet completed its calculation of the total post-1986 E&P as well as non-U.S. income taxes paid for these foreign subsidiaries. Further, the transition tax is based in part on the amount of those earnings held in cash and other specified assets, including trade receivables, based on estimates. The Company expects to revise its estimates of E&P, non-U.S. income taxes and cash balances throughout 2018 when actual results are available. In addition, guidance may be released which could also impact these estimates. Indefinite reinvestment assertion – Beginning in 2018, U.S. Tax Reform provides a 100% deduction for dividends received from 10-percent owned foreign corporations by U.S. corporate shareholders, subject to a one-year holding period. Although dividend income is now exempt from U.S. federal tax for U.S. corporate shareholders, companies must still account for the tax consequences of outside basis differences and other tax impacts of their investments in non-U.S. subsidiaries. As a result of U.S. Tax Reform we have analyzed our global working capital and cash requirements and the potential tax liabilities attributable to a repatriation and have determined that we may repatriate up to $219 million , the majority of which was previously deemed indefinitely reinvested. For those investments from which we were able to make a reasonable estimate of the tax effects of such repatriation, we have recorded a provisional estimate for foreign withholding and state income taxes of $1 million . In addition, we re-measured the existing deferred tax liability accrued on certain acquired Towers Watson subsidiaries and released the deferred tax liability relating to the outside basis difference. This resulted in an income tax benefit of $76 million as these foreign earnings were subject to the one-time transition tax which reduced the outside basis difference. Bonus Depreciation – While the Company has not completed its determination of all capital expenditures that qualify for immediate expensing for the year ended December 31, 2017, the Company recorded a provisional tax deduction of $40 million based on its current intent to fully expense all qualifying expenditures. The Company will analyze the dates all capital expenditures were placed in service or acquired and consider any future guidance within the next twelve months to finalize the deduction. This resulted in an increase of approximately $14 million to the Company's U.S. federal current income taxes receivable and a corresponding increase in its net deferred tax liabilities of approximately $14 million . Executive compensation – Starting with compensation paid in 2018, Section 162(m) will limit the Company from deducting compensation, including performance-based compensation, in excess of $1 million paid to anyone who, starting in 2018, serves as the Chief Executive Officer or Chief Financial Officer, or who is among the three most highly compensated executive officers. The only exception to this rule is for compensation that is paid pursuant to a binding contract in effect on November 2, 2017 that would have otherwise been deductible under the prior Section 162(m) rules. Accordingly, any compensation paid in the future pursuant to new compensation arrangements entered into after November 2, 2017, even if performance-based, will count towards the $1 million deduction limit if paid to a covered executive. The Company recorded a provisional income tax expense of $8 million relating to our compensation plans not qualifying for the binding contract exception. We are in the process of obtaining additional information needed to complete our analysis of the binding contract requirement on the various compensation plans to determine the full impact of the law change. In addition, guidance may be released which could also impact our estimates. The Company's accounting for the following law changes of U.S. Tax Reform is incomplete, and it is not yet able to make reasonable estimates of the effects. Therefore, no provisional adjustment was recorded. GILTI – U.S. Tax Reform creates a new requirement that certain income (i.e., GILTI) earned by controlled foreign corporations (‘CFCs’) must be included currently in the gross income of the CFCs’ U.S. shareholder. GILTI is the excess of the shareholder’s ‘net CFC tested income’ over the net deemed tangible income return, which is currently defined as the excess of (1) 10 percent of the aggregate of the U.S. shareholder’s pro rata share of the qualified business asset investment of each CFC with respect to which it is a U.S. shareholder over (2) the amount of certain interest expense taken into account in the determination of net CFC-tested income. Because of the complexity of the new GILTI tax rules, the Company is continuing to evaluate this provision of U.S. Tax Reform and the application of ASC 740. Under U.S. GAAP, the Company is allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the ‘period cost method’) or (2) factoring such amounts into a company’s measurement of its deferred taxes (the ‘deferred method’). The Company’s selection of an accounting policy with respect to the new GILTI tax rules will depend, in part, on analyzing its global income of its CFCs to determine whether it expects to have future U.S. inclusions in taxable income related to GILTI and, if so, what the impact is expected to be. Because whether the Company expects to have future U.S. inclusions in taxable income related to GILTI depends on not only its current structure and estimated future results of global operations but also its intent and ability to modify its structure and/or its business, the Company is not yet able to reasonably estimate the effect of this provision of U.S. Tax Reform. Therefore, it has not made any adjustments related to potential GILTI tax in its consolidated financial statements and has not made a policy decision. Valuation allowances – The Company must assess whether valuation allowances assessments are affected by various aspects of U.S. Tax Reform (e.g., limitation on net interest expense in excess of 30% of adjusted taxable income). As of December 31, 2017, no changes to valuation allowances have been recorded as a result of U.S. Tax Reform. Provision for income taxes An analysis of income/(loss) before income taxes by taxing jurisdiction is shown below: Years ended December 31, 2017 2016 2015 Ireland $ (23 ) $ (27 ) $ (61 ) U.S. (198 ) (311 ) (67 ) U.K. 31 123 65 Other jurisdictions 679 555 403 Total $ 489 $ 340 $ 340 The components of the income tax provision for/(benefit from) income from operations include: Years ended December 31, 2017 2016 2015 Current tax expense/(benefit): U.S. federal taxes $ 65 $ 35 $ 14 U.S. state and local taxes 7 14 1 U.K. corporation tax 14 28 — Other jurisdictions 99 71 51 Total current tax expense 185 148 66 Deferred tax expense/(benefit): U.S. federal taxes (268 ) (214 ) (113 ) U.S. state and local taxes 6 (5 ) (3 ) U.K. corporation tax (9 ) 10 14 Other jurisdictions (14 ) (35 ) 3 Total deferred tax benefit (285 ) (244 ) (99 ) Total benefit from income taxes $ (100 ) $ (96 ) $ (33 ) The U.S. federal current tax expense includes the impact of a one-time transition tax expense of $70 million related to U.S. Tax Reform which the Company intends to elect to pay over an eight year period without interest. The Company currently estimates that $6 million of this transition tax liability will be paid within the next twelve months. Effective tax rate reconciliation The reported income tax provision for /(benefit from) operations differs from the amounts that would have resulted had the reported income before income taxes been taxed at the U.S. federal statutory rate. The principal reasons for the differences between the amounts provided and those that would have resulted from the application of the U.S. federal statutory tax rate are as follows: Years ended December 31, 2017 2016 2015 INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES $ 489 $ 340 $ 340 U.S. federal statutory income tax rate 35 % 35 % 35 % Income tax expense at U.S. federal tax rate 171 119 119 Adjustments to derive effective tax rate: Non-deductible expenses and dividends 68 15 32 Non-deductible acquisition costs 11 1 9 Disposal of non-deductible goodwill 11 2 3 Gain on re-measurement of equity interests — — (20 ) Impact of change in rate on deferred tax balances — (15 ) (5 ) Effect of foreign exchange and other differences 3 6 (1 ) Non-deductible Venezuelan foreign exchange loss 2 4 11 Changes in valuation allowances 13 (74 ) (104 ) Net tax effect of intra-group items (97 ) (98 ) (30 ) Tax differentials of non-U.S. jurisdictions (69 ) (80 ) (42 ) Tax differentials of U.S. state taxes and local taxes (6 ) 14 (2 ) Impact of U.S. Tax Reform (204 ) — — Other items, net (3 ) 10 (3 ) Benefit from income taxes $ (100 ) $ (96 ) $ (33 ) In connection with our initial analysis of U.S. Tax Reform, the Company has recorded a provisional net tax benefit of $204 million in 2017, which consists of a net benefit of $208 million due to the reduction of the federal corporate tax rate and re-measurement of our net U.S. deferred tax liabilities primarily related to acquisition-based intangibles and a $76 million benefit relating to the release of a deferred tax liability we had previously recorded on the accumulated earnings of certain Towers Watson subsidiaries. These net benefit items are offset by provisional expenses of $8 million recognized as a write-off of a deferred tax asset the Company had previously recorded on executive compensation as well as the U.S. federal and state income tax expense of $72 million associated with the one-time transition tax on foreign earnings of our subsidiaries. Willis Towers Watson plc is a non-trading holding company tax resident in Ireland where it is taxed at the statutory rate of 25% . The provision for income tax on operations has been reconciled above to the U.S. federal statutory tax rate of 35% due to significant operations in the U.S. Deferred income taxes Deferred income tax assets and liabilities reflect the effect of temporary differences between the assets and liabilities recognized for financial reporting purposes and the amounts recognized for income tax purposes. We recognize deferred tax assets if it is more likely than not that a benefit will be realized. Deferred income tax assets and liabilities included in the consolidated balance sheets at December 31, 2017 and 2016 are comprised of the following: December 31, 2017 2016 Deferred tax assets: Accrued expenses not currently deductible $ 131 $ 286 Net operating losses 145 116 Capital loss carryforwards 28 28 Accrued retirement benefits 339 467 Deferred compensation 69 83 Stock options 24 36 Financial derivative transactions 18 12 Gross deferred tax assets 754 1,028 Less: valuation allowance (162 ) (134 ) Net deferred tax assets $ 592 $ 894 Deferred tax liabilities: Cost of intangible assets, net of related amortization $ 929 $ 1,431 Cost of tangible assets, net of related depreciation 56 73 Prepaid retirement benefits 114 85 Accrued revenue not currently taxable 62 119 Deferred tax liabilities $ 1,161 $ 1,708 Net deferred tax liabilities $ 569 $ 814 During December 2017, the Company re-measured its U.S. deferred tax assets and liabilities as a result of U.S. Tax Reform to the newly enacted federal tax rate, which is 21% . The net deferred income tax assets are included in other non-current assets and the net deferred tax liabilities are included in deferred tax liabilities in our consolidated balance sheets. December 31, 2017 2016 Balance sheet classifications: Other non-current assets $ 46 $ 50 Deferred tax liabilities 615 864 Net deferred tax liability $ 569 $ 814 At December 31, 2017, we had U.S. federal and non-U.S. net operating loss carryforwards amounting to $289 million of which $237 million can be indefinitely carried forward under local statutes. The remaining $52 million of net operating loss carryforwards will expire, if unused, in varying amounts from 2018 through 2037. In addition, we had U.S. state net operating loss carryforwards of $1.5 billion , which will expire in varying amounts from 2018 to 2037. Management believes, based on the evaluation of positive and negative evidence, including the future reversal of existing taxable temporary differences, it is more likely than not that the Company will realize the benefits of net deferred tax assets of $592 million , net of the valuation allowance. During 2017 the Company increased its valuation allowance by $28 million primarily due to state net operating losses as it is more likely than not that such losses will not be realized in the foreseeable future. During 2016 the Company released a U.S. valuation allowance of $69 million relating to accrued interest not deductible as a result of deferred tax liabilities recorded for the Merger. The future reversal of the deferred tax liabilities serve as a source of income to recognize the deferred tax asset for accrued interest not deductible. During 2015 the Company released a U.S. valuation allowance of $91 million due to an increase in actual and forecast U.S. earnings. At December 31, 2017 and 2016, the Company had valuation allowances of $162 million and $134 million , respectively, to reduce its deferred tax assets to estimated realizable value. The valuation allowance at December 31, 2017 relates to deferred tax assets for U.K. capital loss carryforwards of $28 million , which have an unlimited carryforward period but can only be utilized against capital gains and U.S. and non-U.S. net operating losses of $80 million and $34 million , respectively. The valuation allowance at December 31, 2016 relates to deferred tax assets for U.K. capital loss carryforwards of $28 million , which have an unlimited carryforward period and U.S. and non-U.S. net operating losses of $78 million and $28 million , respectively. An analysis of our valuation allowance is shown below. Years ended December 31, 2017 2016 2015 Balance at beginning of year $ 134 $ 187 $ 280 Additions charged against/(credited to) to costs and expenses 35 — — Additions charged against/(credited to) to other accounts — 21 2 Deductions (7 ) (74 ) (95 ) Balance at end of year $ 162 $ 134 $ 187 In 2017, the amount charged to tax expense in the table above differs from the 2017 rate reconciliation of $13 million because a portion of the valuation allowance increase is related to the U.S. federal corporate tax rate reduction impact on the U.S. state valuation allowance and is included in the impact of U.S. Tax Reform. The amount charged to tax expense in the table above for 2016 differs from the effect of $74 million disclosed in the 2016 rate reconciliation primarily because the movement in this table includes the effects of acquisition accounting, which does not impact tax expense. The Company recognizes deferred tax balances related to the undistributed earnings of subsidiaries when the Company expects that it will recover those undistributed earnings in a taxable manner, such as through receipt of dividends or sale of the investments. In 2016 we began accruing deferred taxes on the cumulative earnings of certain acquired Towers Watson subsidiaries. The historical cumulative earnings of our other subsidiaries have been reinvested indefinitely. As a result of U.S. Tax Reform, we have analyzed our global working capital and cash requirements and the potential tax liabilities attributable to a repatriation and have determined that we may repatriate up to $219 million , the majority of which was previously deemed indefinitely reinvested. For those investments from which we were able to make a reasonable estimate of the tax effects of such repatriation, we have recorded a provisional estimate for foreign withholding taxes and state income taxes of $1 million . In addition, we re-measured the existing deferred tax liability accrued on certain acquired Towers Watson subsidiaries and released the deferred tax liability relating to the outside basis difference. This resulted in an income tax benefit of $76 million as these foreign earnings were subject to the one-time transition tax which reduced the outside basis difference. The cumulative earnings related to amounts reinvested indefinitely as of December 31, 2017 were approximately $6.8 billion . If future events, including material changes in estimates of cash, working capital, long-term investment requirements or additional guidance relating to U.S. Tax Reform necessitate that these earnings be distributed, an additional provision for income and foreign withholding taxes, net of credits, may be necessary. Uncertain tax positions At December 31, 2017, the amount of unrecognized tax benefits associated with uncertain tax positions, determined in accordance with ASC 740-10, excluding interest and penalties, was $59 million . A reconciliation of the beginning and ending balances of the liability for unrecognized tax benefits is as follows: 2017 2016 2015 Balance at beginning of year $ 56 $ 22 $ 19 Increases related to acquisitions — 33 8 Increases related to tax positions in prior years 2 1 1 Decreases related to tax positions in prior years (5 ) (9 ) (6 ) Decreases related to settlements — (1 ) — Decreases related to lapse in statute of limitations (2 ) (1 ) — Increases related to current year tax positions 9 11 2 Cumulative translation adjustment and other adjustments (1 ) — (2 ) Balance at end of year $ 59 $ 56 $ 22 The liability for unrecognized tax benefits for the years ended December 31, 2017, 2016 and 2015 can be reduced by $3 million , $4 million and nil , respectively, of offsetting deferred tax benefits associated with timing differences, foreign tax credits and the federal tax benefit of state income taxes. If these offsetting deferred tax benefits were recognized, there would have been a favorable impact on our effective tax rate. There are no material balances that would result in adjustments to other tax accounts. Interest and penalties related to unrecognized tax benefits are included as a component of income tax expense. At December 31, 2017, we had cumulative accrued interest of $5 million . At December 31, 2016, the cumulative accrued interest was $4 million . Penalties accrued in 2017 were $2 million and immaterial in 2016. Tax expense for the years ended December 31, 2017 and 2016 included i mmaterial interest benefits . The Company believes that the outcomes which are reasonably possible within the next 12 months may result in a reduction in the liability for unrecognized tax benefits in the range of $4 million to $6 million , excluding interest and penalties. The Company and its subsidiaries file income tax returns in various tax jurisdictions in which it operates. Willis North America Inc. is not currently under examination by the U.S. Internal Revenue Service (‘IRS’). We have ongoing state income tax examinations in certain states for tax years ranging from fiscal year ended June 30, 2012 through calendar year ended December 31, 2015. The statute of limitations in certain states extends back to the fiscal year ended June 30, 2012 as a result of changes to taxable income resulting from prior year federal tax examinations. All U.K. tax returns have been filed timely and are in the normal process of being reviewed by HM Revenue & Customs. The Company is not currently subject to any material examinations in other jurisdictions. A summary of the tax years that remain open to tax examination in our major tax jurisdictions are as follows: Open Tax Years U.S. — federal 2014 and forward U.S. — various states 2012 and forward U.K. 2010 and forward Ireland 2013 and forward France 2010 and forward Germany 2002 and forward Canada - federal 2010 and forward

Fixed Assets

Fixed Assets	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Fixed Assets	Fixed Assets The following table reflects changes in the net carrying amount of the components of fixed assets for the year ended December 31, 2017 and 2016: Furniture, Leasehold Land and Total Cost: at January 1, 2016 $ 724 $ 272 $ 95 $ 1,091 Additions 265 44 2 311 Acquisitions 109 95 — 204 Disposals (28 ) (8 ) — (36 ) Foreign exchange (61 ) (21 ) (7 ) (89 ) Cost: at December 31, 2016 1,009 382 90 1,481 Additions 303 91 — 394 Disposals (61 ) (21 ) — (82 ) Foreign exchange 49 16 4 69 Cost: at December 31, 2017 $ 1,300 $ 468 $ 94 $ 1,862 Depreciation: at January 1, 2016 $ (393 ) $ (94 ) $ (41 ) $ (528 ) Depreciation expense (119 ) (55 ) (4 ) (178 ) Disposals 17 5 — 22 Foreign exchange 31 7 4 42 Depreciation: at December 31, 2016 (464 ) (137 ) (41 ) (642 ) Depreciation expense (i) (199 ) (47 ) (6 ) (252 ) Disposals 37 14 — 51 Foreign exchange (26 ) (6 ) (2 ) (34 ) Depreciation: at December 31, 2017 $ (652 ) $ (176 ) $ (49 ) $ (877 ) Net book value: At December 31, 2016 $ 545 $ 245 $ 49 $ 839 At December 31, 2017 $ 648 $ 292 $ 45 $ 985 ____________________ (i) Depreciation expense included here does not equal the depreciation expense on the statement of comprehensive income for the year ended December 31, 2017 due to the inclusion of $49 million which has been classified as transaction and integration expenses. Included within land and buildings are the following assets held under capital leases: December 31, 2017 2016 Capital leases $ 31 $ 32 Accumulated depreciation (14 ) (12 ) $ 17 $ 20 Depreciation related to capital leases was $2 million for each of the years ended December 31, 2017 , 2016 and 2015 .

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets, Net	Goodwill and Other Intangible Assets 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. Goodwill is allocated to our reporting units primarily based on the original purchase price allocation for acquisitions within the reporting units, or relative fair value when an acquisition covers multiple reporting units. When a business entity is sold, goodwill is allocated to the disposed entity based on the relative fair value of that entity compared with the fair value of the reporting unit in which it was included. The components of goodwill are outlined below for the years ended December 31, 2017 and 2016 : HCB CRB IRR BDA Total Balance at December 31, 2015 Goodwill, gross $ 986 $ 2,212 $ 1,031 $ — $ 4,229 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2015 856 1,850 1,031 — 3,737 Purchase price allocation adjustments 8 5 (7 ) — 6 Goodwill acquired during the period (i) 3,458 — 770 2,557 6,785 Goodwill disposed of during the period — (5 ) — — (5 ) Foreign exchange (40 ) (34 ) (36 ) — (110 ) Balance at December 31, 2016 Goodwill, gross $ 4,412 $ 2,178 $ 1,758 $ 2,557 $ 10,905 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2016 4,282 1,816 1,758 2,557 10,413 Goodwill reassigned in segment realignment (ii) (113 ) 13 100 — — Goodwill acquired during the period — 8 — — 8 Goodwill disposed of during the period (31 ) (5 ) (27 ) — (63 ) Foreign exchange 74 67 20 — 161 Balance at December 31, 2017 Goodwill, gross 4,342 2,261 1,851 2,557 11,011 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2017 $ 4,212 $ 1,899 $ 1,851 $ 2,557 $ 10,519 ____________________ (i) Goodwill acquired consists primarily of goodwill recognized from the Merger. (ii) Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2017. See Note 4 — Segment Information for further information. Other Intangible Assets The following table reflects changes in the net carrying amount of the components of finite-lived intangible assets for the year ended December 31, 2017 : Balance at December 31, 2016 Intangible assets acquired Intangible assets disposed Amortization (ii) Foreign Exchange Balance at December 31, 2017 Client relationships $ 2,655 $ 13 $ (44 ) $ (379 ) $ 97 $ 2,342 Management contracts 54 — — (4 ) 6 56 Software (i) 570 36 — (150 ) 17 473 Trademark and trade name 1,006 — (1 ) (44 ) 5 966 Product 33 — — (3 ) 3 33 Favorable agreements 11 1 — (2 ) — 10 Other 3 — — (1 ) — 2 Total amortizable intangible assets $ 4,332 $ 50 $ (45 ) $ (583 ) $ 128 $ 3,882 ____________________ (i) All in-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ( $36 million at the date placed into service due to changes in foreign currency exchange rates) have been placed into service during the year ended December 31, 2017 and have been included as intangible assets acquired in this presentation. (ii) Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income. The following table reflects changes in the net carrying amount of the components of finite-lived intangible assets for the year ended December 31, 2016 : Balance as of December 31, 2015 Purchase price allocation adjustments Intangible assets acquired Intangible assets disposed Amortization (ii) Foreign Exchange Balance as of December 31, 2016 Client relationships $ 920 2 $ 2,222 $ (5 ) $ (395 ) $ (89 ) $ 2,655 Management contracts 62 — — — (4 ) (4 ) 54 Software (i) 77 (13 ) 675 — (142 ) (27 ) 570 Trademark and trade name 50 1 1,003 — (45 ) (3 ) 1,006 Product — — 42 — (3 ) (6 ) 33 Favorable agreements 2 — 11 — (2 ) — 11 Other 4 — — — (2 ) 1 3 Total amortizable intangible assets $ 1,115 (10 ) $ 3,953 $ (5 ) $ (593 ) $ (128 ) $ 4,332 ____________________ (i) In-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ( $36 million at December 31, 2016) had not yet been placed in service and are not included in this presentation. (ii) Amortization associated with favorable agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income. We recorded amortization related to our finite-lived intangible assets, exclusive of the amortization of our favorable lease agreements, of $581 million , $591 million , and $76 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Our acquired unfavorable lease liabilities were $26 million and $29 million as of December 31, 2017 and December 31, 2016 , respectively, and are recorded in other non-current liabilities in the consolidated balance sheet. The following table reflects the carrying value of finite-lived intangible assets and liabilities at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Client relationships $ 3,462 $ (1,120 ) $ 3,396 $ (741 ) Management contracts 68 (12 ) 62 (8 ) Software 764 (291 ) 711 (141 ) Trademark and trade name 1,055 (89 ) 1,051 (45 ) Product 39 (6 ) 36 (3 ) Favorable agreements 14 (4 ) 13 (2 ) Other 6 (4 ) 6 (3 ) Total finite-lived assets $ 5,408 $ (1,526 ) $ 5,275 $ (943 ) Unfavorable agreements $ 34 $ (8 ) $ 34 $ (5 ) Total finite-lived intangible liabilities $ 34 $ (8 ) $ 34 $ (5 ) The weighted average remaining life of amortizable intangible assets and liabilities at December 31, 2017 was 14.3 years. The table below reflects the future estimated amortization expense for amortizable intangible assets and the rent offset resulting from amortization of the net lease intangible assets and liabilities for the next five years and thereafter: Year ending December 31, Amortization Rent offset 2018 $ 535 $ (4 ) 2019 479 (2 ) 2020 426 (3 ) 2021 348 (2 ) 2022 289 (2 ) Thereafter 1,795 (3 ) Total $ 3,872 $ (16 )

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We are exposed to certain interest rate and foreign currency risks. Where possible, we identify exposures in our business that can be offset internally. Where no natural offset is identified, we may choose to enter into various derivative transactions. These instruments have the effect of reducing our exposure to unfavorable changes in interest and foreign currency rates. The Company’s board of directors reviews and approves policies for managing each of these risks as summarized below. Additional information regarding our derivative financial instruments can be found in Note 2 — Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements , Note 11 — Fair Value Measurements and Note 16 — Accumulated Other Comprehensive Loss . Interest Rate Risk - Investment Income As a result of the Company’s operating activities, the Company holds fiduciary funds. The Company earns interest on these funds, which is included in the Company’s consolidated financial statements in interest and other income. These funds are regulated in terms of access as are the instruments in which they may be invested, most of which are short-term in nature. During 2015, 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. These derivatives, with total notional amounts of $300 million , were designated as hedging instruments at December 31, 2017 and December 31, 2016 and had net fair value liabilities of $1 million and nil , respectively. Foreign Currency Risk Certain non-U.S. subsidiaries receive revenues and incur expenses in currencies other than their functional currency, and as a result, the foreign subsidiary’s functional currency revenues will fluctuate as the currency rates change. Additionally, the forecast Pounds sterling expenses of our London brokerage market operations may exceed their Pounds sterling revenues, and they may also hold a significant net Pounds sterling asset or liability position in the consolidated balance sheet. To reduce such variability, we use foreign exchange contracts to hedge against this currency risk. These derivatives were designated as hedging instruments and at December 31, 2017 and December 31, 2016 had total notional amounts of $937 million and $945 million , respectively, and net fair value liabilities of $21 million and $110 million , respectively. At December 31, 2017 , the Company estimates, based on current interest and exchange rates, there will be $26 million of net derivative losses on forward exchange rates, interest rate swaps, and treasury locks reclassified from accumulated other comprehensive income/(loss) into earnings within the next twelve months as the forecast transactions affect earnings. At December 31, 2017 , our longest outstanding maturity was 2.9 years. The effects of the material derivative instruments that are designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2017, 2016 and 2015 are as follows: Gain/(loss) recognized in OCI Location (Loss)/gain reclassified Location of (loss)/gain recognized in income (Loss)/gain recognized 2017 2016 2015 2017 2016 2015 2017 2016 2015 Foreign exchange contracts $ 39 $ (127 ) $ (38 ) Other expense/(income), net $ (53 ) $ (42 ) $ 4 Interest expense $ (1 ) $ (1 ) $ 1 We also enter into foreign currency transactions, primarily to hedge certain intercompany loans. These derivatives are not generally designated as hedging instruments and at December 31, 2017 and December 31, 2016 , we had notional amounts of $971 million and $630 million , respectively, and had a net fair value asset of $3 million , and a net fair value liability of $8 million , respectively. The effects of derivatives that have not been designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2017 , 2016 and 2015 are as follows: Derivatives not designated as hedging instruments: Location of gain/(loss) recognized in income Gain/(loss) recognized 2017 2016 2015 Foreign exchange contracts Other expense/(income), net $ 11 $ (3 ) $ (3 )

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	Debt Short-term debt and current portion of long-term debt consists of the following: December 31, 2017 2016 6.200% senior notes due 2017 $ — $ 394 Current portion of 7-year term loan facility — 22 Current portion of term loan due 2019 85 85 Short-term borrowing under bank overdraft arrangement — 5 Other debt — 2 $ 85 $ 508 Long-term debt consists of the following: December 31, 2017 2016 Revolving $1.25 billion credit facility $ 884 $ — Revolving $800 million credit facility — 238 7-year term loan facility — 196 Term loan due 2019 84 169 7.000% senior notes due 2019 186 186 5.750% senior notes due 2021 497 496 3.500% senior notes due 2021 447 446 2.125% senior notes due 2022 (i) 644 565 4.625% senior notes due 2023 248 247 3.600% senior notes due 2024 645 — 4.400% senior notes due 2026 544 543 6.125% senior notes due 2043 271 271 $ 4,450 $ 3,357 ________________________ (i) Notes issued in Euro ( €540 million ) Guarantees All direct obligations under the 6.200% (repaid during 2017), 7.000% and 3.600% senior notes are issued by Willis North America Inc. and guaranteed by Willis Towers Watson, Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited. See Note 21 — Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries. All direct obligations under the 5.750% senior notes are issued by the Company and guaranteed by Trinity Acquisition plc, Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Willis North America Inc., Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited. See Note 22 — Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries. All direct obligations under the 4.625%, 6.125%, 3.500%, 4.400%, and 2.125% senior notes are issued by Trinity Acquisition plc and guaranteed by Willis Towers Watson, Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Willis North America Inc., Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited. See Note 23 — Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries. Revolving Credit Facility $1.25 billion revolving credit facility On March 7, 2017, Trinity Acquisition plc (see Note 23 for further information) entered into a $1.25 billion amended and restated revolving credit facility (the ‘RCF’), that will mature on March 7, 2022. The RCF replaced the previous $800 million revolving credit facility (see below for further information). Amounts outstanding under the RCF shall bear interest at LIBOR plus a margin of 1.00% to 1.75% , or alternatively, the base rate plus a margin of 0.00% to 0.75% , based upon the Company’s guaranteed senior unsecured long-term debt rating. Borrowings of $409 million and €45 million against the RCF were used to repay all outstanding borrowings against the previous $800 million revolving credit facility and the 7 -year term loan due July 23, 2018. Additionally, on March 28, 2017, $407 million was used to repay the 6.200% senior notes due 2017, including accrued interest. $800 million revolving credit facility Drawings under the previous $800 million revolving credit facility bore interest at LIBOR plus a margin of 1.25% to 2.00% , or alternatively the base rate plus a margin of 0.25% to 1.00% based upon the Company’s guaranteed senior unsecured long-term debt rating; a 1.375% margin applied while the Company’s debt rating remained BBB/Baa3 . At December 31, 2016 , $238 million was outstanding under this revolving credit facility. WSI revolving credit facility Willis Securities Inc. (‘WSI’) maintained a $400 million revolving credit facility. The WSI revolving credit facility expired on April 28, 2017. As of December 31, 2017 and 2016 , there were no borrowings outstanding under the WSI revolving credit facility. Senior Notes 3.600% senior notes due 2024 On May 16, 2017, Willis North America Inc. (see Note 21 for further information) issued $650 million of 3.600% senior notes due 2024 (‘2024 senior notes’). The effective interest rate of the 2024 senior notes is 3.614% , which includes the impact of the discount upon issuance. The 2024 senior notes will mature on May 15, 2024, and interest accrues on the 2024 senior notes from May 16, 2017 and will be paid in cash on May 15 and November 15 of each year. The net proceeds from this offering, after deducting underwriter discounts and commissions and estimated offering expenses, were $644 million , and were used to pay down amounts outstanding under the RCF and for general corporate purposes. 2.125% senior notes due 2022 On May 26, 2016, Trinity Acquisition plc issued €540 million ( $609 million ) of 2.125% senior notes due 2022 (‘2022 senior notes’). The 2022 senior notes are fully and unconditionally guaranteed by Willis Towers Watson. The effective interest rate of these senior notes is 2.154% , which includes the impact of the discount upon issuance. The 2022 senior notes will mature on May 26, 2022. Interest accrues on the notes from May 26, 2016 and will be paid in cash on May 26 of each year. The net proceeds from this offering, after deducting underwriter discounts and commissions and estimated offering expenses, were €535 million ( $600 million ) . We used the net proceeds of this offering to repay Tranche A of the previous 1 -year term loan facility, which matured in 2016, and related accrued interest. 3.500% senior notes due 2021 and 4.400% senior notes due 2026 On March 22, 2016, Trinity Acquisition plc issued $450 million of 3.500% senior notes due 2021 (‘2021 senior notes’) and $550 million of 4.400% senior notes due 2026 (‘2026 senior notes’). The 2021 senior notes and the 2026 senior notes are fully and unconditionally guaranteed by the Company. The effective interest rates of these senior notes are 3.707% and 4.572% , respectively, which includes the impact of the discount upon issuance. The 2021 senior notes and the 2026 senior notes will mature on September 15, 2021 and March 15, 2026, respectively. Interest accrues on the notes from March 22, 2016 and will be paid in cash on March 15 and September 15 of each year. The net proceeds from these offerings, after deducting underwriter discounts and commissions and estimated offering expenses, were $988 million . We used the net proceeds of these offerings to: (i) repay $300 million principal under the prior $800 million revolving credit facility and related accrued interest, which was drawn to repay our previously issued 4.125% senior notes on March 15, 2016; (ii) repay $400 million principal on Tranche B of the previous 1 -year term loan facility and related accrued interest; and (iii) pay down a portion of the remaining principal amount outstanding under the previous $800 million revolving credit facility and related accrued interest. 4.625% senior notes due 2023 and 6.125% senior notes due 2043 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. The proceeds were used to repurchase other previously issued senior notes. 5.750% senior notes due 2021 In March 2011, the Company issued $500 million of 5.750% senior notes due 2021. The effective interest rate of this senior note is 5.871% , which includes the impact of the discount upon issuance. The proceeds were used to repurchase and redeem other previously issued senior notes. 7.000% senior notes due 2019 In September 2009, Willis North America Inc. issued $300 million of 7.000% senior notes due 2019. The effective interest rates of these senior notes are 7.081% , which include the impact of the discount upon issuance. A portion of the proceeds were used to repurchase and redeem other previously issued senior notes. In August 2013, $113 million of the 7.000% senior notes due 2019 were repurchased. Term Loan Facilities 7-year term loan facility The 7 -year term loan facility expiring 2018 bore interest at the same rate applicable to the previous $800 million revolving credit facility and was repayable in quarterly installments of $6 million with a final repayment of $186 million due in the third quarter of 2018. During 2017, we repaid in full and terminated the 7 -year term loan with proceeds from borrowings against our $1.25 billion revolving credit facility. Term loan due December 2019 On January 4, 2016, we acquired a $340 million term loan in connection with the Merger. On November 20, 2015, Towers Watson Delaware Inc. entered into a four -year amortizing term loan agreement for up to $340 million with a consortium of banks to help fund the pre-Merger special dividend. On December 28, 2015, Towers Watson Delaware Inc. borrowed the full $340 million . The interest rate on the term loan is based on the Company’s choice of one, two, three or six-month LIBOR plus a spread of 1.25% to 1.75% , or alternatively the bank base rate plus 0.25% to 0.75% . The spread to each index is dependent on the Company’s consolidated leverage ratio. The weighted-average interest rate on this term loan for the year ended December 31, 2017 was 2.33% . The term loan amortizes at a rate of $21 million per quarter, beginning in March 2016, with a final maturity date of December 2019. The Company has the right to prepay a portion or all of the outstanding term loan balance on any interest payment date without penalty. At December 31, 2017 , the balance outstanding on the term loan was $170 million , before reduction of $1 million in debt issuance fees. Additional Information Regarding Fully Repaid Term Loan Facility and Senior Notes 1-year term loan facility On November 20, 2015, Legacy Willis entered into a 1 -year term loan facility. The 1-year term loan had two tranches: Tranche A was for €550 million , of which €544 million ( $592 million ) was drawn on December 19, 2015 and used to finance the acquisition of Gras Savoye. Tranche B was for $400 million and was drawn on January 4, 2016 and used to re-finance debt held by Legacy Towers Watson which became due on acquisition. Tranche A was repaid in its entirety on May 26, 2016 from the proceeds from the issuance of our 2022 senior notes discussed above. Tranche B was repaid in its entirety on March 22, 2016 from a portion of the proceeds from the issuance of our senior notes discussed above. The amount outstanding as of December 31, 2015 was $592 million , gross of $5 million in debt fees related to the 1 -year term loan facility. 4.125% senior notes due 2016 In March 2011, the Company issued $300 million of 4.125% senior notes due 2016. The effective interest rate of the senior notes was 4.240% , which included the impact of the discount upon issuance. The proceeds were used to repurchase and redeem other previously issued senior notes. 6.200% senior notes due 2017 On March 28, 2007, we issued $600 million of 10 year senior notes at 6.200% . The effective interest rate of these senior notes was 6.253% . In August 2013, $206 million of the 6.200% senior notes were repurchased. The final balance was repaid on March 28, 2017 from the RCF as discussed above. Covenants The terms of our current financings also include certain limitations. For example, the agreements relating to the debt arrangements and credit facilities generally contain numerous operating and financial covenants, including requirements to maintain minimum ratios of consolidated EBITDA to consolidated cash interest expense and maximum levels of consolidated funded indebtedness in relation to consolidated EBITDA, in each case subject to certain adjustments. The operating restrictions and financial covenants in our credit facilities do, and any future financing agreements may, limit our ability to finance future operations or capital needs or to engage in other business activities. At December 31, 2017 and 2016, we were in compliance with all financial covenants. Debt Maturity The following table summarizes the maturity of our debt, interest on senior notes and excludes any reduction for debt issuance costs: 2018 2019 2020 2021 2022 Thereafter Total Senior notes $ — $ 187 $ — $ 950 $ 644 $ 1,725 $ 3,506 Interest on senior notes 147 144 134 107 82 464 1,078 Term loans 85 85 — — — — 170 RCF — — — — 884 — 884 Total $ 232 $ 416 $ 134 $ 1,057 $ 1,610 $ 2,189 $ 5,638 Interest Expense The following table shows an analysis of the interest expense for the years ended December 31: Years ended December 31, 2017 2016 2015 Senior notes $ 148 $ 139 $ 114 Term loans 8 17 5 RCF 17 10 6 WSI revolving credit facility 1 2 2 Other (i) 14 16 15 Total interest expense $ 188 $ 184 $ 142 ________________________ (i) Other primarily includes debt issuance costs, interest expense on capitalized leases and accretion on deferred and contingent consideration.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company has categorized its assets and liabilities that are measured at fair value on a recurring and non-recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows: • Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets; • Level 2: refers to fair values estimated using observable market based inputs or unobservable inputs that are corroborated by market data; and • Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data. The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments: • Available-for-sale securities are classified as Level 1 because we use quoted market prices in determining the fair value of these securities. • Market values for our derivative instruments 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 observable information about the current interest rate environment or current foreign currency forward rates. Such financial instruments are classified as Level 2 in the fair value hierarchy. • Contingent consideration payable is classified as Level 3, and we estimate fair value based on the likelihood and timing of achieving the relevant milestones of each arrangement, applying a probability assessment to each of the potential outcomes, and discounting the probability-weighted payout. Typically, milestones are based on revenue or EBITDA growth for the acquired business. The following tables present our assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 : Balance Sheet Location Fair Value Measurements on a Recurring Basis at December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds / exchange traded funds Prepaid and other current assets and other non-current assets $ 40 $ — $ — $ 40 Derivatives: Derivative financial instruments (i) Prepaid and other current assets and other non-current assets $ — $ 18 $ — $ 18 Liabilities: Contingent consideration: Contingent consideration (ii) Other current liabilities and other non-current liabilities $ — $ — $ 51 $ 51 Derivatives: Derivative financial instruments (i) Other current liabilities and other non-current liabilities $ — $ 37 $ — $ 37 Balance Sheet Location Fair Value Measurements on a Recurring Basis at December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds / exchange traded funds Prepaid and other current assets and other non-current assets $ 37 $ — $ — $ 37 Derivatives: Derivative financial instruments (i) Prepaid and other current assets and other non-current assets $ — $ 15 $ — $ 15 Liabilities: Contingent consideration: Contingent consideration (ii) Other current liabilities and other non-current liabilities $ — $ — $ 55 $ 55 Derivatives: Derivative financial instruments (i) Other current liabilities and other non-current liabilities $ — $ 133 $ — $ 133 ____________________ (i) See Note 9 — Derivative Financial Instruments for further information on our derivative instruments. (ii) Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The weighted-average discount rate used on our material contingent consideration calculations was 9.64% and 10.76% at December 31, 2017 and December 31, 2016, respectively. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable. The following table summarizes the change in fair value of the Level 3 liabilities: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) December 31, 2017 Balance at December 31, 2016 $ 55 Obligations assumed — Net sales (7 ) Payments (10 ) Realized and unrealized gains 9 Foreign exchange 4 Balance at December 31, 2017 $ 51 There were no significant transfers between Levels 1, 2 or 3 during the years ended December 31, 2017 and 2016 . Fair value information about financial instruments not measured at fair value The following tables present our liabilities not measured at fair value on a recurring basis at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Short-term debt and current portion of long-term debt $ 85 $ 85 $ 508 $ 513 Long-term debt $ 4,450 $ 4,706 $ 3,357 $ 3,504 The carrying values of our revolving lines of credit and term loans approximate their fair values. The fair values above 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. The fair value of our respective senior notes are considered level 2 financial instruments as they are corroborated by observable market data.

Retirement Benefits

Retirement Benefits	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Retirement Benefits	Retirement Benefits Defined Benefit Plans and Post-retirement Welfare Plans Willis Towers Watson sponsors both qualified and non-qualified defined benefit pension plans and other post-retirement welfare plans (‘PRW’) plans throughout the world. The majority of our plan assets and obligations are in the United States and the United Kingdom. We have also included disclosures related to defined benefit plans in certain other countries, including Canada, France, Germany, Ireland and the Netherlands. Together, these disclosed funded and unfunded plans represent 99% of Willis Towers Watson’s pension and PRW obligations and are disclosed herein. On January 4, 2016, in connection with the Merger, we acquired additional defined benefit pension, PRW, and defined contribution plans. Total plan assets of approximately $3.7 billion and projected benefit obligations of approximately $4.6 billion were acquired. The funded status for each of the acquired plans has been included in the values of identifiable assets acquired, and liabilities assumed in Note 3 — Merger, Acquisitions and Divestitures and are recorded as $67 million in pension benefits assets and $923 million in liability for pension benefits. As part of these obligations, in the United States, the United Kingdom and Canada, we have non-qualified plans that provide for the additional pension benefits that would be covered under the qualified plan in the respective country were it not for statutory maximums. The non-qualified plans are unfunded. The significant plans within each grouping are described below: United States Legacy Willis – This plan was frozen in 2009. Approximately one-quarter of the Legacy Willis employees in the United States have a frozen accrued benefit under this plan. Willis Towers Watson Plan – Substantially all U.S. employees are eligible to participate in this plan. Benefits are provided under a stable value pension plan design. The original stable value design came into effect on January 1, 2012. As of July 1, 2017, existing plan participants earn benefits without having to make employee contributions, and all newly eligible employees are required to contribute 2% of pay to participate in the plan. United Kingdom Legacy Willis – This plan covers approximately one third of the Legacy Willis employees in the United Kingdom. The plan is now closed to new entrants. New employees in the United Kingdom are offered the opportunity to join a defined contribution plan. Legacy Towers Watson – Benefit accruals earned under the Legacy Watson Wyatt defined benefit plan (predominantly pension benefits) ceased on February 28, 2015, although benefits earned prior to January 1, 2008 retain a link to salary until the employee leaves the Company. Benefit accruals earned under the legacy Towers Perrin defined benefit plan (predominantly lump sum benefits) were frozen on March 31, 2008. All participants now accrue defined contribution benefits. Legacy Miller – The plan provides retirement benefits based on members’ salaries at the point at which they ceased to accrue benefits under the scheme. Other Canada (Legacy Towers Watson) – Participants accrue qualified and non-qualified benefits based on a career average benefit formula. Additionally, participants can choose to make voluntary contributions to purchase enhancements to their pension. France (Legacy Gras Savoye) – The mandatory retirement indemnity plan is a termination benefit which provides lump sum benefits at retirement. There is no vesting before the retirement date and the benefit formula is determined through the collective bargaining agreement and the labor code. All employees with permanent employment contracts are eligible. Germany (Legacy Willis) – The defined benefit plan population consists of retirees receiving annuities and three participants with deferred vested benefits. Other employees and former employees participate in defined contribution arrangements. Germany (Legacy Towers Watson) – Effective January 1, 2011, all new participants participate in a defined contribution plan. Participants hired prior to this date continue to participate in various defined contribution and defined benefit arrangements according to legacy plan formulas. The legacy defined benefit plans are primarily account-based, with some long-service participants continuing to accrue benefits according to grandfathered final-average-pay formulas. Ireland (Legacy Willis) – The defined benefit plans provide pension benefits for approximately one third of legacy Willis employees in Ireland. The defined benefit plans are now closed to new entrants. Ireland (Legacy Towers Watson) – Benefit accruals earned under the scheme’s defined benefit plan ceased on May 1, 2015. Benefits earned prior to this date retain a link to salary until the employee leaves the Company. Netherlands (Legacy Towers Watson) – Benefits under the plan used to accrue on a final pay basis on earnings up to a maximum amount each year. The benefit accrual under the final pay plan stopped at December 31, 2010. The accrued benefits will receive conditional indexation each year. Post-retirement Welfare Plan We provide certain healthcare and life insurance benefits for retired participants. The principal plans cover participants in the U.S. who have met certain eligibility requirements. Our principal post-retirement benefit plans are primarily unfunded. Retiree medical benefits provided under our U.S. post-retirement benefit plans were closed to new hires effective January 1, 2011. Life insurance benefits under the plans were frozen with respect to service, eligibility and amounts as of January 1, 2012 for active participants. Amounts Recognized in our Consolidated Financial Statements The following schedules provide information concerning the defined benefit pension plans and PRW plan as of and for the years ended December 31, 2017 and 2016 : 2017 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Change in Benefit Obligation Benefit obligation, beginning of year $ 4,169 $ 3,899 $ 732 $ 113 $ 976 $ 2,881 $ 184 $ — Service cost 66 32 20 — 59 24 19 1 Interest cost 139 93 17 4 137 114 18 3 Employee contributions 6 1 — 6 — 1 — 7 Actuarial losses 293 2 5 14 151 852 61 4 Settlements (16 ) (138 ) (1 ) — — (12 ) (61 ) — Benefits paid (181 ) (93 ) (29 ) (14 ) (166 ) (130 ) (24 ) (14 ) Business combinations — — — — 3,012 842 530 112 Transfers in — — 1 — — — 1 — Foreign currency changes — 369 77 — — (673 ) 4 — Benefit obligation, end of year $ 4,476 $ 4,165 $ 822 $ 123 $ 4,169 $ 3,899 $ 732 $ 113 Change in Plan Assets Fair value of plan assets, beginning of year $ 3,280 $ 4,360 $ 467 $ 4 $ 749 $ 3,478 $ 158 $ — Actual return on plan assets 464 290 42 — 153 782 26 — Employer contributions 101 66 34 6 91 106 39 7 Employee contributions 6 1 — 6 — 1 — 7 Settlements (16 ) (138 ) (1 ) — — (12 ) (58 ) — Benefits paid (181 ) (93 ) (29 ) (14 ) (166 ) (130 ) (24 ) (14 ) Business combinations — — — — 2,453 906 321 4 Transfers in — — 1 — — — 1 — Foreign currency adjustment — 424 48 — — (771 ) 4 — Fair value of plan assets, end of year $ 3,654 $ 4,910 $ 562 $ 2 $ 3,280 $ 4,360 $ 467 $ 4 Funded status at end of year $ (822 ) $ 745 $ (260 ) $ (121 ) $ (889 ) $ 461 $ (265 ) $ (109 ) Accumulated Benefit Obligation $ 4,476 $ 4,165 $ 790 $ 123 $ 4,169 $ 3,899 $ 696 $ 113 Components on the Consolidated Balance Sheet Pension benefits assets $ — $ 754 $ 17 $ — $ — $ 478 $ 10 $ — Current liability for pension benefits $ (40 ) $ — $ (6 ) $ (5 ) $ (47 ) $ — $ (7 ) $ (3 ) Non-current liability for pension benefits $ (782 ) $ (9 ) $ (271 ) $ (116 ) $ (842 ) $ (17 ) $ (268 ) $ (106 ) $ (822 ) $ 745 $ (260 ) $ (121 ) $ (889 ) $ 461 $ (265 ) $ (109 ) Amounts recognized in accumulated other comprehensive loss as of December 31, 2017 and 2016 consist of: 2017 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Net actuarial loss $ 663 $ 909 $ 79 $ 19 $ 603 $ 918 $ 80 $ 4 Net prior service gain — (142 ) — — — (147 ) — — Accumulated other comprehensive loss $ 663 $ 767 $ 79 $ 19 $ 603 $ 771 $ 80 $ 4 The following table presents the projected benefit obligation and fair value of plan assets for our plans that have a projected benefit obligation in excess of plan assets as of December 31, 2017 and 2016 : 2017 2016 U.S. U.K. Other U.S. U.K. Other Projected benefit obligation at end of year $ 4,476 $ 10 $ 758 $ 4,169 $ 843 $ 686 Fair value of plan assets at end of year $ 3,654 $ — $ 481 $ 3,280 $ 825 $ 411 The following table presents the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for our plans that have an accumulated benefit obligation in excess of plan assets as of December 31, 2017 and 2016 . 2017 2016 U.S. U.K. Other U.S. U.K. Other Projected benefit obligation at end of year $ 4,476 $ 10 $ 758 $ 4,169 $ 843 $ 686 Accumulated benefit obligation at end of year $ 4,476 $ 10 $ 726 $ 4,169 $ 843 $ 650 Fair value of plan assets at end of year $ 3,654 $ — $ 481 $ 3,280 $ 825 $ 411 The components of the net periodic benefit income and other amounts recognized in other comprehensive (income)/loss for the years ended December 31, 2017, 2016 and 2015 for the defined benefit pension and PRW plans are as follows: 2017 2016 2015 U.S. U.K. Other PRW U.S. U.K. Other PRW U.S. U.K. Other PRW Components of net periodic benefit (income)/cost: Service cost $ 66 $ 32 $ 20 $ — $ 59 $ 24 $ 19 $ 1 $ — $ 33 $ 3 $ — Interest cost 139 93 17 4 137 114 18 3 41 107 3 — Expected return on plan assets (245 ) (284 ) (30 ) — (240 ) (253 ) (27 ) — (57 ) (230 ) (3 ) — Amortization of unrecognized prior service credit — (18 ) — — — (19 ) — — — (18 ) — — Amortization of unrecognized actuarial loss 13 53 2 — 12 42 — — 11 36 1 — Settlement 1 37 1 — — — 5 — — — — — Curtailment gain — — — — — — — — — (5 ) — — Net periodic benefit (income)/cost $ (26 ) $ (87 ) $ 10 $ 4 $ (32 ) $ (92 ) $ 15 $ 4 $ (5 ) $ (77 ) $ 4 $ — Other changes in plan assets and benefit obligations recognized in other comprehensive loss/(income): Net actuarial loss/(gain) $ 74 $ (4 ) $ (7 ) $ 14 $ 238 $ 323 $ 62 $ 4 $ (16 ) $ 59 $ (5 ) $ — Amortization of unrecognized actuarial loss (13 ) (53 ) (2 ) — (12 ) (42 ) — — (11 ) (36 ) (1 ) — Prior service gain — — — — — — — — — (215 ) — — Amortization of unrecognized prior service credit — 18 — — — 19 — — — 18 — — Settlement (1 ) (37 ) (1 ) — — — (8 ) — — — — — Curtailment loss — — — — — — — — — 18 — — Total recognized in other comprehensive loss/(income) 60 (76 ) (10 ) 14 226 300 54 4 (27 ) (156 ) (6 ) — Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income) $ 34 $ (163 ) $ — $ 18 $ 194 $ 208 $ 69 $ 8 $ (32 ) $ (233 ) $ (2 ) $ — During the year ended December 31, 2017, as a result of past changes in UK legislation and the low interest rate environment, the amount of transfer payments from the Legacy Willis UK pension plan exceeded the plan’s service and interest cost. This triggers settlement accounting which requires immediate recognition of a portion of the obligations associated with the plan transfers. Consequently, the Company recognized a non-cash expense of $36 million . During fiscal year 2016, we adopted the granular approach to calculating service and interest cost. This was treated as a change in accounting estimate, and resulted in a credit of $51 million included in our total net periodic benefit income reflected above. On March 6, 2015, Legacy Willis announced to members of the U.K. defined benefit pension plan that, effective from June 30, 2015, future salary increases would not be pensionable (the ‘salary freeze’). Legacy Willis recognized the salary freeze as a plan amendment at the announcement date. The impact of the salary freeze reduced the plan’s projected benefit obligation by approximately $215 million and created a prior service credit which is recognized in other comprehensive income and then amortized to the consolidated statement of comprehensive income over the remaining expected service life of active employees. The estimated net actuarial loss and prior service gain for the defined benefit plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year are: For the Year Ended December 31, 2018 U.S. U.K Other PRW Estimated net actuarial loss $ 11 $ 47 $ 2 $ 1 Prior service gain $ — $ (19 ) $ — $ — Assumptions Used in the Valuations of the Defined Benefit Pension Plans and PRW Plan The determination of the Company’s obligations and annual expense under the plans is based on a number of assumptions that, given the longevity of the plans, are long-term in focus. A change in one or a combination of these assumptions could have a material impact on our projected benefit obligation. However, certain of these changes, such as changes in the discount rate and actuarial assumptions, are not recognized immediately in net income, but are instead recorded in other comprehensive income. The accumulated gains and losses not yet recognized in net income are amortized into net income as a component of the net periodic benefit cost/(credit) generally based on the average working life expectancy of the plan’s active participants to the extent that the net gains or losses as of the beginning of the year exceed 10% of the greater of the market-related value of plan assets or the projected benefit obligation. The average remaining service period of participants for the PRW plan is approximately 9.9 years . The Company considers several factors prior to the start of each fiscal year when determining the appropriate annual assumptions, including economic forecasts, relevant benchmarks, historical trends, portfolio composition and peer company comparisons. These assumptions, used to determine our pension liabilities and pension expense, are reviewed annually by senior management and changed when appropriate. The discount rate will be changed annually if underlying rates have moved, whereas the expected long-term return on assets will be changed less frequently as longer term trends in asset returns emerge or long-term target asset allocations are revised. To calculate the discount rate, we use the granular approach to determining service and interest costs. The expected rate of return assumptions for all plans are supported by an analysis of the weighted-average yield expected to be achieved based upon the anticipated makeup of the plans’ investments. Other material assumptions include rates of participant mortality, and the expected long-term rate of compensation and pension increases. The following assumptions were used in the valuations of Willis Towers Watson’s defined benefit pension plans and PRW plan. The assumptions presented for the U.S. plans represent the weighted-average of rates for all U.S. plans. The assumptions presented for the U.K. plans represent the weighted-average of rates for the U.K. plans. The assumptions presented for the Other plans represent the weighted-average of rates for the Canada, France, Germany, Ireland, and Netherlands plans. The assumptions used to determine net periodic benefit cost for the fiscal years ended December 31, 2017, 2016, and 2015 were as follows: Years ended December 31, 2017 2016 2015 U.S. U.K. Other PRW U.S. U.K. Other PRW U.S. U.K. Other PRW Discount rate (i) N/A N/A N/A N/A N/A N/A N/A N/A 3.9 % 3.6 % 2.3 % — % Discount rate - PBO 4.0 % 2.6 % 2.7 % 4.0 % 4.2 % 3.8 % 3.2 % 4.2 % N/A N/A N/A — % Discount rate - service cost 3.9 % 2.6 % 3.0 % 3.9 % 3.9 % 3.8 % 3.4 % 4.1 % N/A N/A N/A — % Discount rate - interest cost on service cost 3.2 % 2.4 % 2.8 % 3.5 % 3.2 % 3.8 % 3.1 % 3.5 % N/A N/A N/A — % Discount rate - interest cost on PBO 3.4 % 2.3 % 2.3 % 3.3 % 3.4 % 3.4 % 2.8 % 3.3 % N/A N/A N/A — % Expected long-term rate of return on assets 7.6 % 6.3 % 6.1 % 2.0 % 7.6 % 6.2 % 6.1 % 2.0 % 7.3 % 6.5 % 3.3 % — % Rate of increase in compensation levels 4.3 % 3.2 % 2.3 % N/A 4.3 % 3.2 % 2.3 % N/A N/A 2.9 % 2.2 % — % Healthcare cost trend Initial rate 7.0 % 7.0 % N/A Ultimate rate 5.0 % 5.0 % N/A Year reaching ultimate rate 2022 2022 N/A ____________________ (i) This discount rate represents the assumption to determine net periodic benefit cost prior to the Company’s use of the granular approach to calculating service and interest cost which began for the 2016 fiscal year. The following tables present the assumptions used in the valuation to determine the projected benefit obligation for the fiscal years ended December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Discount rate 3.6 % 2.6 % 2.6 % 3.5 % 4.0 % 2.6 % 2.7 % 4.0 % Rate of increase in compensation levels 4.3 % 3.0 % 2.3 % N/A 4.3 % 3.2 % 2.3 % N/A A one percentage point change in the assumed healthcare cost trend rates would have an immaterial effect on the post-retirement benefit cost and obligation as of December 31, 2017. The expected return on plan assets was determined on the basis of the weighted-average of the expected future returns of the various asset classes, using the target allocations shown below. The Company’s pension plan asset target allocations as of December 31, 2017 were as follows: U.S. U.K. Canada Germany Ireland Asset Category Willis Towers Watson Willis Towers Watson Miller Towers Watson Towers Watson Willis Towers Watson Equity securities 35 % 23 % 33 % 11 % 33 % 60 % 30 % 32 % 71 % Debt securities 54 % 43 % 47 % 56 % 55 % 40 % 51 % 27 % 29 % Real estate 11 % 6 % 2 % — % — % — % — % 3 % — % Other — % 28 % 18 % 33 % 12 % — % 19 % 38 % — % Total 100 % 100 % 100 % 100 % 100 % 100 % 100 % 100 % 100 % The Legacy Willis plan in Germany and the Legacy Towers Watson plan in the Netherlands are invested in insurance contracts. Consequently, the asset allocations of the plans are managed by the insurer. The Legacy Gras Savoye plan in France is unfunded. Our investment strategy is designed to generate returns that will reduce the interest rate risk inherent in each of the plan’s benefit obligations and enable the plans to meet their future obligations. The precise amount for which these obligations will be settled depends on future events, including the life expectancy of the plan participants and salary inflation. The obligations are estimated using actuarial assumptions, based on the current economic environment. Each pension plan seeks to achieve total returns sufficient to meet expected future obligations when considered in conjunction with expected future contributions and prudent levels of investment risk and diversification. Each plan’s targeted asset allocation is generally determined through a plan-specific Asset-Liability Modeling study. These comprehensive studies provide an evaluation of the projected status of asset and benefit obligation measures for each plan under a range of both positive and negative environments. The studies include a number of different asset mixes, spanning a range of diversification and potential equity exposures. In evaluating the strategic asset allocation choices, an emphasis is placed on the long-term characteristics of each individual asset class, such as expected return, volatility of returns and correlations with other asset classes within the portfolios. Consideration is also given to the proper long-term level of risk for each plan, the impact of the volatility and magnitude of plan contributions and costs, and the impact that certain actuarial techniques may have on the plan’s recognition of investment experience. We monitor investment performance and portfolio characteristics on a quarterly basis to ensure that managers are meeting expectations with respect to their investment approach. There are also various restrictions and controls placed on managers, including prohibition from investing in our stock. Fair Value of Plan Assets The fair value hierarchy has three levels based on the reliability of the inputs used to determine fair value: • 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 fair values of our U.S. plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 10 $ — $ — $ 10 $ 3 $ — $ — $ 3 Short-term securities — 283 — 283 — 33 — 33 Equity securities 202 — — 202 253 8 — 260 Government bonds 10 — — 10 10 — — 10 Corporate bonds — 193 — 193 — 169 — 170 Other fixed income — 20 — 20 — 19 — 19 Pooled / commingled funds — — — 1,922 — — — 1,665 Mutual funds 1 — — 1 183 — — 183 Private equity — — — 287 — — — 234 Hedge funds — — — 724 — — — 692 Total assets $ 223 $ 496 $ — $ 3,652 $ 449 $ 229 $ — $ 3,269 The fair values of our U.K. plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 92 $ — $ — $ 92 $ 49 $ — $ — $ 49 Equity securities 24 — — 24 374 8 — 382 Government bonds 1,841 — — 1,841 1,184 — — 1,184 Corporate bonds — 224 — 224 — 118 — 118 Other fixed income — 246 — 246 — 216 — 216 Pooled / commingled funds — — — 2,294 — — — 1,677 Mutual funds — — — 8 — — — 11 Private equity — — — 32 — — — 40 Derivatives — 102 — 102 — 73 — 73 Real estate — — — 218 — — — 197 Hedge funds — — — 393 — — — 426 Total assets $ 1,957 $ 572 $ — $ 5,474 $ 1,607 $ 415 $ — $ 4,373 Liability category: Repurchase agreements — 549 — 549 — — — — Derivatives — 16 — 16 — 14 — 14 Net assets $ 1,957 $ 7 $ — $ 4,909 $ 1,607 $ 401 $ — $ 4,359 The fair values of our Other plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 5 $ — $ — $ 5 $ 17 $ — $ — $ 17 Pooled / commingled funds — — — 327 — — — 214 Mutual funds — — — 209 — — — 224 Insurance contracts — — 19 19 — — 17 17 Total assets $ 5 $ — $ 19 $ 560 $ 17 $ — $ 17 $ 472 Our PRW plan invests only in short-term investments and mutual funds and is not included within this fair value hierarchy table. We evaluate the need to transfer between levels based upon the nature of the financial instrument and size of the transfer relative to the total net assets of the plans. There were no significant transfers between Levels 1, 2 or 3 in the fiscal years ended December 31, 2017 and 2016 . In accordance with Subtopic 820-10, Fair Value Measurement and Disclosures , certain investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in these tables are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of net assets. Following is a description of the valuation methodologies used for investments at fair value: Short-term securities : Valued at the net value of shares held by the Company at year end as reported by the sponsor of the funds. Equity securities and Mutual Funds: Valued at the closing price reported on the active market on which the individual securities are traded. Exchange traded mutual funds are included as Level 1 above. Government bonds : Valued at the closing price reported in the active market in which the bond is traded. Corporate bonds: Valued using pricing models maximizing the use of observable inputs for similar securities. This includes basing value on yields currently available on comparable securities of issuers with similar credit ratings. Other Fixed Income : Foreign and municipal bonds are valued at the closing price reported in the active market in which the bond is traded. Pooled / Commingled Funds and Mutual Funds : Valued at the net value of shares held by the Company at year end as reported by the manager of the funds. These funds are not exchange traded and are not reported by level in the tables above. Derivative investments : Valued at the closing level of the relevant index or security and interest accrual through the valuation date. Private equity funds, Real estate funds, Hedge funds: The fair value for these investments is estimated based on the net asset value derived from the latest audited financial statements or most recent capital account statements provided by the private equity fund’s investment manager or third-party administrator. Insurance contracts: The fair values are determined using model-based techniques that include option-pricing models, discounted cash flow models and similar techniques. Repurchase agreements: Valued as the repurchase obligation which includes an interest rate linked to the underlying fixed interest government bond portfolio. These agreements are short-term in nature (less than one year) and were entered into for the purpose of purchasing additional government bonds. The following table reconciles the net plan investments to the total fair value of the plan assets: December 31, 2017 2016 Net assets held in investments $ 9,121 $ 8,100 PRW plan assets 2 3 Net receivable for investments purchased 2 3 Dividend and interest receivable 3 3 Fair value of plan assets $ 9,128 $ 8,109 Level 3 investments As a result of the inherent limitations related to the valuations of the Level 3 investments, due to the unobservable inputs of the underlying funds, the estimated fair value may differ significantly from the values that would have been used had a market for those investments existed. The following table sets forth a summary of changes in the fair value of the plans’ Level 3 assets for the fiscal year ended December 31, 2017 : Level 3 Roll Forward Beginning balance at December 31, 2016 $ 17 Foreign exchange 2 Ending balance at December 31, 2017 $ 19 Contributions and Benefit Payments Funding is based on actuarially determined contributions and is limited to amounts that are currently deductible for tax purposes. Since funding calculations are based on different measurements than those used for accounting purposes, pension contributions are not equal to net periodic pension costs. The following table sets forth our projected pension contributions to our qualified plans for fiscal year 2018, as well as the pension contributions to our qualified plans in fiscal years 2017 and 2016: 2018 2017 2016 U.S. $ 50 $ 50 $ 50 U.K. $ 81 $ 65 $ 105 Other $ 13 $ 13 $ 29 Expected benefit payments from our defined benefit pension plans to current plan participants, including the effect of their expected future service, as appropriate, are as follows: Benefit Payments Fiscal Year U.S. U.K. Other PRW Total 2018 230 112 36 16 394 2019 236 111 26 17 390 2020 245 117 27 18 407 2021 249 127 29 19 424 2022 260 129 36 20 445 Years 2023 – 2027 1,386 764 179 117 2,446 $ 2,606 $ 1,360 $ 333 $ 207 $ 4,506 Defined Contribution Plan We have defined contribution plans covering eligible employees in many countries. The most significant plans are in the U.S. and U.K. and are described here. We have a U.S. defined contribution plan covering all eligible employees of Willis Towers Watson (the ‘Plan’). The Plan allows participants to make pre-tax and Roth after-tax contributions and provides a 100% match by us on the first 1% of employee contributions and 50% match on the next 5% of employee contributions. Employees vest in the employer match upon 2 years of service. All investment assets of the plan are held in a trust account administered by independent trustees. The Legacy Towers Watson U.K. pension plan has a money purchase component to which we make core contributions plus additional contributions matching those of the participants up to a maximum rate. Contribution rates depend on the age of the participant and whether or not they arise from salary sacrifice arrangements through which the participant has elected to receive a pension contribution in lieu of additional salary. The Legacy Willis U.K. pension plan has a money purchase component to which we make core contributions plus additional contributions matching those of the participants up to a maximum rate. Contribution rates may arise from salary sacrifice arrangements through which the participant has elected to receive a pension contribution in lieu of additional salary. We made contributions to our defined contribution plans for the years ended December 31, 2017, 2016, and 2015 amounting to $154 million , $152 million and $77 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company leases certain land, building and equipment under various operating lease commitments. The total amount of the minimum rent is expensed on a straight-line basis over the term of the lease. Rental expenses and sub-lease rental income for operating leases are recorded as part of other operating expenses in the consolidated statements of comprehensive income. Rental expense, exclusive of sublease income, was $302 million , $302 million , and $142 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. We have entered into sublease agreements for some of our excess leased space. Sublease income was $21 million , $17 million and $17 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. As of December 31, 2017 , the aggregate future minimum rental commitments under all non-cancellable operating lease agreements are as follows: Gross rental Rentals from Net rental 2018 $ 204 $ (16 ) $ 188 2019 191 (13 ) 178 2020 165 (13 ) 152 2021 138 (10 ) 128 2022 120 (4 ) 116 Thereafter 585 (5 ) 580 Total $ 1,403 $ (61 ) $ 1,342 Guarantees Guarantees issued by certain of Willis Towers Watson’s subsidiaries with respect to the senior notes and revolving credit facilities are discussed in Note 10 — Debt . Certain of Willis Towers Watson’s subsidiaries have given the landlords of some leasehold properties occupied by the Company in the United Kingdom and the United States guarantees in respect of the performance of the lease obligations of the subsidiary holding the lease. The operating lease obligations subject to such guarantees amounted to $669 million and $558 million at December 31, 2017 and 2016 , respectively. The capital lease obligations subject to such guarantees amounted to $8 million and $9 million as of December 31, 2017 and 2016 , respectively. Acquisition liabilities The Company has deferred and contingent consideration due to be paid on existing acquisitions until 2019 totaling $96 million at December 31, 2017 . Most notably, our liability for the acquisition of Miller Insurance Services LLP in May 2015, for which deferred and contingent consideration, including interest, was $78 million at December 31, 2017 . Total deferred and contingent consideration paid during the year ended December 31, 2017 was $65 million . Other contractual obligations For certain subsidiaries and associates, the Company has the right to purchase shares (a call option) from co-shareholders at various dates in the future. In addition, the co-shareholders of certain subsidiaries and associates have the right to sell their shares (a put option) to the Company at various dates in the future. Generally, the exercise price of such put options and call options is formula-based (using revenues and earnings) and is designed to reflect fair value. Based on current projections of profitability and exchange rates, and assuming the put options are exercised, the potential amount payable from these options is not expected to exceed $34 million . In July 2010, the Company made a capital commitment of $25 million to Trident V Parallel Fund, LP, an investment fund managed by Stone Point Capital. This replaced a capital commitment of $25 million that had been made to Trident V, LP in December 2009. As of December 31, 2017 there have been approximately $24 million of capital contributions. In May 2011, the Company made a capital commitment of $10 million to Dowling Capital Partners I, LP. As of December 31, 2017 there had been approximately $9 million of capital contributions. Other contractual obligations at December 31, 2017 and 2016 , include certain capital lease obligations totaling $48 million and $54 million , respectively, primarily in respect of the Company’s Nashville property. Indemnification Agreements Willis Towers Watson has various agreements which provide that it may be obligated to indemnify the other party to the agreement with respect to certain matters. Generally, these indemnification provisions are included in contracts arising in the normal course of business and in connection with the purchase and sale of certain businesses. Although it is not possible to predict the maximum potential amount of future payments that may become due under these indemnification agreements because of the conditional nature of Willis Towers Watson’s obligations and the unique facts of each particular agreement, Willis Towers Watson does not believe any potential liability that might arise from such indemnity provisions is probable or material. There are no provisions for recourse to third parties, nor are any assets held by any third parties that any guarantor can liquidate to recover amounts paid under such indemnities. Legal Proceedings In the ordinary course of business, the Company is subject to various actual and potential claims, lawsuits, and other proceedings. Some of the claims, lawsuits and other proceedings seek damages in amounts which could, if assessed, be significant. We do not expect the impact of claims or demands not described below to be material to the Company’s consolidated financial statements. The Company also receives subpoenas in the ordinary course of business and, from time to time, receives requests for information in connection with governmental investigations. Errors and omissions claims, lawsuits, and other proceedings arising in the ordinary course of business are covered in part by professional indemnity or other appropriate insurance. See Note 14 for the amounts accrued at December 31, 2017 and 2016 in the consolidated balance sheets. The terms of this insurance vary by policy year. Regarding self-insured risks, the Company has established provisions which are believed to be adequate in the light of current information and legal advice, or, in certain cases, where a range of loss exists, the Company accrues the minimum amount in the range if no amount within the range is a better estimate than any other amount. The Company adjusts such provisions from time to time according to developments. 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 or settlement in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in particular quarterly or annual periods. In addition, given the early stages of some litigation or regulatory proceedings described below, it is not possible to predict their outcome or resolution, and it is possible that these events may have a material adverse effect on the Company. The Company provides for contingent liabilities based on ASC 450, Contingencies, when it is determined that a liability, inclusive of defense costs, is probable and reasonably estimable. The contingent liabilities recorded are primarily developed actuarially. Litigation is subject to many factors which are difficult to predict so there can be no assurance that in the event of a material unfavorable result in one or more claims, we will not incur material costs. Merger-related Appraisal Demands Between November 12, 2015 and December 10, 2015, in connection with the then-proposed Merger, Towers Watson received demands for appraisal under Section 262 of the Delaware General Corporation Law on behalf of ten purported beneficial owners of an aggregate of approximately 2.4% of the shares of Towers Watson common stock outstanding at the time of the Merger. Between March 3, 2016 and March 23, 2016, three appraisal petitions were filed in the Court of Chancery for the State of Delaware on behalf of three purported beneficial owners of Towers Watson common stock, captioned Rangeley Capital LLC v. Towers Watson & Co., C.A. No. 12063-CB, Merion Capital L.P. v. Towers Watson & Co., C.A. No. 12064-CB, and College Retirement Equities Fund v. Towers Watson & Co., C.A. No. 12126-CB. The appraisal petitions seek, among other things, a determination of the fair value of the appraisal petitioners’ shares at the time of the Merger; an order that Towers Watson pay that value to the appraisal petitioners, together with interest at the statutory rate; and an award of costs, attorneys’ fees, and other expenses. Towers Watson answered the appraisal petitions between March 24, 2016 and April 18, 2016. On May 9, 2016, the court consolidated the three pending appraisal proceedings under the caption In re Appraisal of Towers Watson & Co. , Consolidated C.A. No. 12064-CB. A fourth owner filed an appraisal demand, but did not file an appraisal petition. The aggregate amount of shares subject to appraisal from these four owners was 1,415,199 . The court provisionally scheduled trial for October 2, 2017. On September 15, 2017, the Company reached a settlement with all shareholders who made demands for appraisal, resolving all claims related to the appraised shares. Under the terms of the settlement, these shareholders surrendered all rights to the Towers Watson shares and all potential Merger consideration issuable for the legacy shares. In exchange, the Company made a payment to these shareholders of approximately $211 million , which represented $134.75 per share plus accrued interest at the statutory rate of interest. As a result of the settlement, the Court, on September 18, 2017, dismissed all claims in the case with prejudice. The Company thereafter canceled all of the Towers Watson common shares at issue in the appraisal proceeding. Merger-Related Securities Litigation On November 21, 2017, a purported former stockholder of Legacy Towers Watson filed a putative class action complaint on behalf of a putative class consisting of all Legacy Towers Watson stockholders as of October 2, 2015 against the Company, Legacy Towers Watson, Legacy Willis, ValueAct Capital Management (‘ValueAct’), and certain current and former directors and officers of Legacy Towers Watson and Legacy Willis (John Haley, Dominic Casserley, and Jeffrey Ubben), in the United States District Court for the Eastern District of Virginia. The complaint asserts claims against certain defendants under Section 14(a) of the Securities Exchange Act of 1934 (the ‘Exchange Act’) for allegedly false and misleading statements in the proxy statement for the Merger; and against other defendants under Section 20(a) of the Exchange Act for alleged “control person” liability with respect to such allegedly false and misleading statements. The complaint further contends that the allegedly false and misleading statements caused stockholders of Legacy Towers Watson to accept inadequate Merger consideration. The complaint seeks damages in an unspecified amount. On February 20, 2018, the court appointed the Regents of the University of California as Lead Plaintiff and Bernstein Litowitz Berger & Grossman LLP as Lead Counsel for the putative class, consolidated all subsequently filed, removed, or transferred actions, and captioned the consolidated action “In re Willis Towers Watson plc Proxy Litigation,” Master File No. 1:17-cv-1338-AJT-JFA. Lead Plaintiff has indicated that it intends to file a consolidated amended complaint. On February 27, 2018, another purported former stockholder of Legacy Towers Watson filed a putative class action complaint on behalf of a putative class of Legacy Towers Watson stockholders against the former members of the Legacy Towers Watson board of directors, Legacy Towers Watson, Legacy Willis and ValueAct, in the Delaware Court of Chancery, captioned City of Fort Myers General Employees’ Pension Fund v. Towers Watson & Co., et al., C.A. No. 2018-0132. Based on similar allegations, the complaint asserts claims against the former directors of Legacy Towers Watson for breach of fiduciary duty and against Legacy Willis and ValueAct for aiding and abetting breach of fiduciary duty. The defendants have not yet responded to the complaint. The Company disputes the allegations in these actions and intends to defend the lawsuits vigorously. Given the stage of the proceedings, the Company is unable to provide an estimate of the reasonably possible loss or range of loss in respect of the complaints. Stanford Financial Group The Company has been named as a defendant in 15 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 15 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 (‘Roland’). 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 in 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. Opening briefs were filed on May 3, 2013 and the Supreme Court heard oral argument on October 7, 2013. On February 26, 2014, the Supreme Court affirmed the Fifth Circuit’s decision. On March 19, 2014, the plaintiffs in Troice filed a Motion to Defer Resolution of Motions to Dismiss, to Compel Rule 26(f) Conference and For Entry of Scheduling Order. On March 25, 2014, the parties in Troice and the Janvey, et al. v. Willis of Colorado, Inc., et al. action discussed below stipulated to the consolidation of the two actions for pre-trial purposes under Rule 42(a) of the Federal Rules of Civil Procedure. On March 28, 2014, the Court ‘so ordered’ that stipulation and, thus, consolidated Troice and Janvey for pre-trial purposes under Rule 42(a). On September 16, 2014, the court (a) denied the plaintiffs’ request to defer resolution of the defendants’ motions to dismiss, but granted the plaintiffs’ request to enter a scheduling order; (b) requested the submission of supplemental briefing by all parties on the defendants’ motions to dismiss, which the parties submitted on September 30, 2014; and (c) entered an order setting a schedule for briefing and discovery regarding plaintiffs’ motion for class certification, which schedule, among other things, provided for the submission of the plaintiffs’ motion for class certification (following the completion of briefing and discovery) on April 20, 2015. On December 15, 2014, the court granted in part and denied in part the defendants’ motions to dismiss. On January 30, 2015, the defendants except Willis Group Holdings plc answered the Third Amended Class Action Complaint. On April 20, 2015, the plaintiffs filed their motion for class certification, the defendants filed their opposition to plaintiffs’ motion, and the plaintiffs filed their reply in further support of the motion. Pursuant to an agreed stipulation also filed with the court on April 20, 2015, the defendants on June 4, 2015 filed sur-replies in further opposition to the motion. The Court has not yet scheduled a hearing on the motion. On June 19, 2015, Willis Group Holdings plc filed a motion to dismiss the complaint for lack of personal jurisdiction. On November 17, 2015, Willis Group Holdings plc withdrew the motion. On March 31, 2016, the parties in the Troice and Janvey actions entered into a settlement in principle that is described in more detail below. • 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 . On August 26, 2014, the plaintiff filed a notice of voluntary dismissal of the action without prejudice. • 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. On August 13, 2012, the plaintiffs filed a motion to lift the stay, which motion was denied by the court on September 16, 2014. On October 10, 2014, the plaintiffs appealed the court’s denial of their motion to lift the stay to the U.S. Court of Appeals for the Fifth Circuit. On January 5, 2015, the Fifth Circuit consolidated the appeal with the appeal in the Rishmague, et ano. v. Winter, et al. action discussed below, and the consolidated appeal, was fully briefed as of March 24, 2015. Oral argument on the consolidated appeal was held on September 2, 2015. On September 16, 2015, the Fifth Circuit affirmed. 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. On February 13, 2015, the parties filed an Agreed Motion for Partial Dismissal pursuant to which they agreed to the dismissal of certain claims pursuant to the motion to dismiss decisions in the Troice action discussed above and the Janvey action discussed below. Also on February 13, 2015, the defendants except Willis Group Holdings plc answered the complaint in the Casanova action. On June 19, 2015, Willis Group Holdings plc filed a motion to dismiss the complaint for lack of personal jurisdiction. Plaintiffs have not opposed the motion. • 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. On August 13, 2012, the plaintiffs joined with the plaintiffs in the Rupert action in their motion to lift the court’s stay of the Rupert action. On September 9, 2014, the court remanded Rishmague to Texas state court (Bexar County), but stayed the action until further order of the court and denied the plaintiffs’ motion to lift the stay. On October 10, 2014, the plaintiffs appealed the court’s denial of their motion to lift the stay to the Fifth Circuit. On January 5, 2015, the Fifth Circuit consolidated the appeal with the appeal in the Rupert action, and the consolidated appeal was fully briefed as of March 24, 2015. Oral argument on the consolidated appeal was held on September 2, 2015. On September 16, 2015, the Fifth Circuit affirmed. 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. On September 29, 2014, the parties stipulated to the remand (to Texas state court (Harris County)) and stay of MacArthur until further order of the court (in accordance with the court’s September 9, 2014 decision in Rishmague (discussed above)), which stipulation was ‘so ordered’ by the court on October 14, 2014. The defendants have not yet responded to the complaint in MacArthur . • Florida suits : On February 14, 2013, five lawsuits 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. On September 30, 2014, the court denied the plaintiffs’ motion to remand in Zacarias , and, on October 3, 2014, the court denied the plaintiffs’ motions to remand in Tisminesky and de Gadala Maria . On December 3, 2014 and March 3, 2015, the court granted the plaintiffs’ motions to remand in Barbar and Ranni , respectively, remanded both actions to Florida state court (Miami-Dade County) and stayed both actions until further order of the court. On January 2, 2015 and April 1, 2015, the plaintiffs in Barbar and Ranni , respectively, appealed the court’s December 3, 2014 and March 3, 2015 decisions to the Fifth Circuit. On April 22, 2015 and July 22, 2015, respectively, the Fifth Circuit dismissed the Barbar and Ranni appeals sua sponte for lack of jurisdiction. The defendants have not yet responded to the complaints in Ranni or Barbar . On April 1, 2015, the defendants except Willis Group Holdings plc filed motions to dismiss the complaints in Zacarias , Tisminesky and de Gadala-Maria . On June 19, 2015, Willis Group Holdings plc filed motions to dismiss the complaints in Zacarias , Tisminesky and de Gadala-Maria for lack of personal jurisdiction. On July 15, 2015, the court dismissed the complaint in Zacarias in its entirety with leave to replead within 21 days . On July 21, 2015, the court dismissed the complaints in Tisminesky and de Gadala-Maria in their entirety with leave to replead within 21 days . On August 6, 2015, the plaintiffs in Zacarias , Tisminesky and de Gadala-Maria filed amended complaints (in which, among other things, Willis Group Holdings plc was no longer named as a defendant). On September 11, 2015, the defendants filed motions to dismiss the amended complaints. The motions await disposition by the court. • Janvey, et al. v. Willis of Colorado, Inc., et al. , Case No. 3:13-CV-03980-D, was filed on October 1, 2013 also in 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. As alleged by the Stanford Receiver, the total amount of collective losses allegedly sustained by all investors in Stanford certificates of deposit is approximately $4.6 billion . On November 15, 2013, plaintiffs in Janvey filed the operative First Amended Complaint, which added certain defendants unaffiliated with Willis. On February 28, 2014, the defendants filed motions to dismiss the First Amended Complaint, which motions, other than with respect to Willis Group Holding plc’s motion to dismiss for lack of personal jurisdiction, were granted in part and denied in part by the court on December 5, 2014. On December 22, 2014, Willis filed a motion to amend the court’s December 5 order to certify an interlocutory appeal to the Fifth Circuit, and, on December 23, 2014, Willis filed a motion to amend and, to the extent necessary, reconsider the court’s December 5 order. On January 16, 2015, the defendants answered the First Amended Complaint. On January 28, 2015, the court denied Willis’s motion to amend the court’s December 5 order to cert

Supplementary Information for C

Supplementary Information for Certain Balance Sheet Accounts	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplementary Information for Select Balance Sheet Accounts	Supplementary Information for Certain Balance Sheet Accounts Additional details of specific balance sheet accounts are detailed below. Accounts receivable, net consists of the following: December 31, December 31, Billed, net of allowance for doubtful debts of $45 million and $40 million $ 1,933 $ 1,789 Accrued and unbilled, at estimated net realizable value 313 291 Accounts receivable, net $ 2,246 $ 2,080 Accounts receivable are stated at estimated net realizable values. The provisions, shown below as of the end of each period, are recorded as the amounts considered by management to be sufficient to meet probable future losses related to uncollectible accounts. December 31, December 31, December 31, Balance at beginning of year $ 40 $ 22 $ 12 Additions charged to costs and expenses 17 36 5 Charges to other accounts - acquisitions — 8 11 Deductions/other movements (9 ) (27 ) (7 ) Foreign exchange (3 ) 1 1 Balance at end of year $ 45 $ 40 $ 22 Prepaid and other current assets consist of the following: December 31, December 31, Prepayments and accrued income $ 132 $ 131 Derivatives and investments 29 32 Deferred compensation plan assets 21 15 Retention incentives 7 7 Corporate income and other taxes 170 97 Other current assets 71 55 Total prepaid and other current assets $ 430 $ 337 Other non-current assets consist of the following: December 31, December 31, Prepayments and accrued income $ 18 $ 15 Deferred compensation plan assets 135 111 Deferred tax assets 46 50 Accounts receivable, net 33 27 Other investments 26 30 Other non-current assets 189 120 Total other non-current assets $ 447 $ 353 Other current liabilities consist of the following: December 31, December 31, Accounts payable $ 136 $ 117 Income and other taxes payable 90 91 Contingent and deferred consideration on acquisition 55 53 Payroll-related liabilities 209 200 Derivatives 32 80 Third party commissions 172 184 Other current liabilities 110 151 Total other current liabilities $ 804 $ 876 Provision for liabilities consists of the following: December 31, December 31, Claims, lawsuits and other proceedings $ 474 $ 508 Other provisions 84 67 Total provision for liabilities $ 558 $ 575 Other non-current liabilities consist of the following: December 31, December 31, Incentives from lessors $ 138 $ 133 Deferred compensation plan liability 135 111 Contingent and deferred consideration on acquisitions 41 89 Derivatives 5 51 Other non-current liabilities 225 148 Total other non-current liabilities $ 544 $ 532

Other Expense_(Income), Net

Other Expense/(Income), Net	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Other Expense/(Income), Net	Other expense/(income), net consists of the following: Years ended December 31, 2017 2016 2015 Gain on disposal of operations $ (13 ) $ (2 ) $ (25 ) Gain on re-measurement of equity interests (i) — — (59 ) Impact of Venezuelan currency devaluation (ii) 2 — 30 Foreign exchange loss/(gain) 72 29 (1 ) Other expense/(income), net $ 61 $ 27 $ (55 ) ____________________ (i) Prior to the acquisition date, the Company accounted for its 30% interest in Gras Savoye as an equity-method investment. The acquisition-date fair value of the previously held equity interest was $158 million and is included in the measurement of the consideration transferred. The Company recognized a gain of $59 million as a result of remeasuring its prior equity interest in Gras Savoye held before the business combination. (ii) On December 31, 2015 the Company began using the SIMADI rate for the Venezuelan bolivar (approximately Venezuelan bolivars 198.7 = U.S. dollar 1) instead of the SICAD I auction rate (approximately Venezuelan bolivars 13.5 = U.S. dollar 1) to translate on Venezuelan retail operations. In March 2016, the DICOM mechanism replaced the SIMADI mechanism. At December 31, 2017, the DICOM rate was approximately Venezuelan bolivars 3,345 = U.S. dollar 1. The Company does not expect the additional devaluation which occurred in January 2018 to be material.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Loss	The components of other comprehensive income/(loss) are as follows: December 31, 2017 December 31, 2016 December 31, 2015 Before tax amount Tax Net of tax amount Before tax amount Tax Net of tax amount Before tax amount Tax Net of tax amount Other comprehensive income/(loss): Foreign currency translation $ 295 $ — $ 295 $ (353 ) $ — $ (353 ) $ (133 ) $ — $ (133 ) Defined pension and post-retirement benefits 3 11 14 (553 ) 114 (439 ) 233 (53 ) 180 Derivative instruments 90 (15 ) 75 (87 ) 12 (75 ) (35 ) 7 (28 ) Other comprehensive income/(loss) 388 (4 ) 384 (993 ) 126 (867 ) 65 (46 ) 19 Less: Other comprehensive (income)/loss attributable to non-controlling interests (13 ) — (13 ) 20 — 20 10 — 10 Other comprehensive income/(loss) attributable to Willis Towers Watson $ 375 $ (4 ) $ 371 $ (973 ) $ 126 $ (847 ) $ 75 $ (46 ) $ 29 Changes in the components of accumulated other comprehensive loss, net of tax, are included in the following table. This table excludes amounts attributable to non-controlling interests, which are not material for further disclosure. Foreign currency translation (i) Cash flow hedges (i) Defined pension and post-retirement benefit costs (ii) Total Balance, January 1, 2015 $ (191 ) $ 18 $ (893 ) $ (1,066 ) Other comprehensive (loss)/income before reclassifications (123 ) (31 ) 158 4 Loss reclassified from accumulated other comprehensive loss (net of income tax expense of $8) — 3 22 25 Net other comprehensive (loss)/income (123 ) (28 ) 180 29 Balance, December 31, 2015 $ (314 ) $ (10 ) $ (713 ) $ (1,037 ) Other comprehensive loss before reclassifications (336 ) (110 ) (483 ) (929 ) Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $5) — 38 44 82 Net other comprehensive loss (336 ) (72 ) (439 ) (847 ) Balance, December 31, 2016 $ (650 ) $ (82 ) $ (1,152 ) $ (1,884 ) Other comprehensive income/(loss) before reclassifications 285 28 (26 ) 287 Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $18) — 44 40 84 Net other comprehensive income 285 72 14 371 Balance, December 31, 2017 $ (365 ) $ (10 ) $ (1,138 ) $ (1,513 ) ____________________ (i) Reclassification adjustments from accumulated other comprehensive income are included in Other expense/(income), net in the accompanying consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the hedge settlements. (ii) Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 12 — Retirement Benefits ) which is included in Salaries and benefits in the accompanying consolidated statements of comprehensive income .

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-based Compensation Plan Summaries On December 31, 2017 , the Company had a number of open share-based compensation plans, which provide for the grant of time-based and performance-based options, time-based and performance-based restricted stock units, and various other share-based grants to employees. All of the Company’s share-based compensation plans under which any options, restricted stock units or other share-based grants are outstanding as of December 31, 2017 are described below. The compensation cost that has been recognized for these plans for the years ended December 31, 2017 , 2016 and 2015 was $67 million , $123 million and $64 million , respectively. The total income tax benefit recognized in the consolidated statement of comprehensive income for share-based compensation arrangements for the years ended December 31, 2017, 2016, and 2015 was $22 million , $35 million and $15 million , respectively. 2012 Equity Incentive Plan This plan, which was established on April 25, 2012 , provides for the granting of incentive stock options, time-based or performance-based non-statutory stock options, share appreciation rights, restricted shares, time-based or performance-based RSUs, performance-based awards and other share-based grants or any combination thereof (collectively referred to as ‘Awards’) to employees, officers, non-employee directors and consultants (‘Eligible Individuals’) of the Company. The board of directors also adopted a sub-plan under the 2012 plan to provide an employee sharesave scheme in the United Kingdom. There were approximately 7 million shares remaining available for grant under this plan as of December 31, 2017. Options are exercisable on a variety of dates, including from the second, third, fourth or fifth anniversary of grant. Unless terminated sooner by the board of directors, the 2012 Plan will expire 10 years after the date of its adoption. That termination will not affect the validity of any grants outstanding at that date. Towers Watson Share Plans In January 2016, in connection with the Merger, we assumed the Towers Watson & Co. 2009 Long-Term Incentive Plan (‘LTIP’) and converted the outstanding unvested restricted stock units and options into Willis Towers Watson RSUs and options using a conversion ratio stated in the Merger Agreement. We determined the fair value of the portion of the outstanding RSUs and options related to pre-acquisition employee service using the straight-line methodology from date of grant to the acquisition date to be $37 million , which was added to the transaction consideration. The fair value of the remaining portion of RSUs and options related to the post-acquisition employee services was $45 million , and is being recorded over the future vesting periods. For the years ended December 31, 2017 and 2016, we recorded $11 million and $31 million of non-cash stock based compensation, respectively. The acquired awards include performance-vested RSUs. Under the RSU agreement, participants become vested in a number of RSUs based on the achievement of specified levels of financial performance during the performance period set forth in the Merger Agreement, provided that the participant remains in continuous service with us through the end of the performance period. Dividend equivalents will accrue on these RSUs and vest to the same extent as the underlying shares. The Compensation Committee of the board of directors may provide for continuation of vesting of RSUs upon an employee’s termination under certain circumstances such as qualified retirement. The definition of qualified retirement is age 55 with 15 years of service with the Company and a minimum of one year service in the performance period. Due to the terms of the RSU agreement, the achievement of the level of financial performance is determined at the higher of 100% or the level attained at the time of the Merger. The Company does not intend to grant future awards under the 2009 LTIP plan. Employee Stock Purchase Plans The Company adopted the Willis Group Holdings 2010 North America Employee Stock Purchase Plan, which expires on May 31, 2020. These plans provide certain eligible employees in the United States and Canada with the ability to contribute payroll deductions to the purchase of Willis Towers Watson ordinary shares at the end of each offering period. Share-based Compensation Valuation Assumptions Options The fair value of each option is estimated on the date of grant using the Black-Scholes option pricing model that uses the assumptions noted in the following table. Expected volatility is based on historical volatility of the Company’s shares. The Company uses the simplified method set out in ASC 718 – Compensation – Stock Compensation to derive the expected term of options granted as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The risk-free rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year. Years ended December 31, 2017 2016 2015 Expected volatility 19.8 % 21.0 % 17.4 % Expected dividends 1.4 % 1.5 % 2.7 % Expected life (years) 4.2 2.7 4.0 Risk-free interest rate 1.6 % 0.7 % 1.5 % Share-based Compensation Award Activity Options Classification of options as time-based or performance-based is dependent on the original terms of the award. Performance conditions on the majority of options have been met. A summary of option activity under the plans at December 31, 2017 , and changes during the year then ended is presented below: Options Weighted- Weighted- Aggregate (thousands) Price (i) Term Value Time-based stock options Balance as of December 31, 2016 1,201 $ 102.38 Granted 38 $ 143.60 Exercised (448 ) $ 100.61 Forfeited (37 ) $ 103.22 Balance as of December 31, 2017 754 $ 105.47 4 years $ 34 Options vested or expected to vest at December 31, 2017 751 $ 105.17 4 years $ 34 Options exercisable at December 31, 2017 581 $ 101.43 4 years $ 29 Performance-based stock options Balance as of December 31, 2016 883 $ 101.95 Exercised (182 ) $ 87.49 Forfeited (21 ) $ 82.90 Balance as of December 31, 2017 680 $ 106.42 4 years $ 30 Options vested or expected to vest at December 31, 2017 680 $ 106.42 4 years $ 30 Options exercisable at December 31, 2017 190 $ 95.36 1 year $ 11 ____________________ (i) Certain options are exercisable in Pounds sterling and are converted to dollars using the exchange rate at December 31, 2017. The weighted-average grant-date fair values of time-based options granted during the years ended December 31, 2017, 2016 and 2015 were $27.69 , $16.88 and $14.77 , respectively. The total intrinsic values of options exercised during the years ended December 31, 2017, 2016 and 2015 were $19 million , $25 million and $17 million , respectively. At December 31, 2017 there was $2 million of total unrecognized compensation cost related to nonvested share-based compensation arrangements under time-based stock option plans; that cost is expected to be recognized over a weighted-average period of 2.4 years. There were no performance-based options granted during the three years ended December 31, 2017 , 2016 or 2015 . However, 520,295 performance-based options were acquired during the year ended December 31, 2016, at which time the performance conditions were met. The total intrinsic value of options exercised during the years ended December 31, 2017, 2016 and 2015 was $10 million , $9 million and $25 million , respectively. At December 31, 2017 there remains an immaterial amount of total unrecognized compensation cost related to nonvested share-based compensation arrangements under performance-based stock option plans; that cost is expected to be recognized over a weighted-average period of 6 months . RSUs The fair value of each time-based RSU is based on the grant date fair value, or the fair value on the acquisition date in the case of acquired awards. The fair value of each performance-based RSU is estimated on the grant date using a Monte-Carlo simulation that uses the assumptions noted in the following table. Expected volatility is based on the historical volatility of the Company’s shares. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of the grant. The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year. There were no performance-based RSUs granted during the year ended December 31, 2015. Years ended December 31, 2017 2016 Expected volatility 20.2 % 20.3 % Expected dividend yield — % — % Expected life (years) 2.4 2.6 Risk-free interest rate 1.4 % 0.8 % A summary of time-based and performance-based RSU activity under the plans at December 31, 2017 , and changes during the year then ended, is presented below: Shares Weighted- (thousands) Fair Value Nonvested shares (time-based RSUs) Balance, beginning of year 437 $ 118.98 Granted 17 $ 153.40 Vested (179 ) $ 119.50 Forfeited (132 ) $ 119.09 Balance, end of year 143 $ 122.27 Nonvested shares (performance-based RSUs) Balance, beginning of year 1,200 $ 121.78 Granted 140 $ 148.18 Vested (319 ) $ 119.63 Forfeited (140 ) $ 121.30 Balance, end of year 881 $ 90.61 The total number of time-based RSUs that vested during the year ended December 31, 2017 was 178,574 shares at an average share price of $150.81 . The total number of time-based RSUs that vested during the year ended December 31, 2016 was 459,838 shares at an average share price of $120.42 .The total number of RSUs that vested during the year ended December 31, 2015 was 408,032 shares at an average share price of $117.72 . At December 31, 2017 there was $11 million of total unrecognized compensation cost related to nonvested share-based compensation arrangements under the plan; that cost is expected to be recognized over a weighted-average period of 0.8 years . The total number of performance-based RSUs that vested during the year ended December 31, 2017 was 318,714 shares at an average share price of $140.32 . The total number of performance-based RSUs that vested during the year ended December 31, 2016 was 258,536 shares at an average share price of $119.75 . The total number of performance-based RSUs that vested during the year ended December 31, 2015 was 63,180 shares at an average share price of $117.88 . At December 31, 2017 there was $28 million of total unrecognized compensation cost related to nonvested performance-based share-based compensation arrangements under the plan; that cost is expected to be recognized over a weighted-average period of 1.5 years. Cash received from option exercises under all share-based payment arrangements for the years ended December 31, 2017, 2016 and 2015 was $61 million , $63 million and $124 million , respectively. The actual tax benefit recognized for the tax deductions from option exercises of the share-based payment arrangements totaled $7 million , $6 million and $12 million for the years ended December 31, 2017 , 2016 and 2015, respectively. The actual tax benefit recognized for the tax deductions from RSUs that vested totaled $19 million , $25 million and $13 million for the years ended December 31, 2017 , 2016 and 2015, respectively .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
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 Towers Watson by the average number of ordinary shares outstanding during each period. The computation of diluted earnings per share reflects the potential dilution that could occur if dilutive securities and other contracts to issue shares were exercised or converted into shares or resulted in the issuance of shares that then shared in the net income of the Company. At December 31, 2017 and 2016 , there were 0.8 million and 1.2 million time-based share options; 0.7 million and 0.9 million performance-based options; 0.1 million and 0.4 million restricted time-based stock units; and 0.9 million and 1.2 million restricted performance-based stock units outstanding, respectively. Basic and diluted earnings per share are as follows: Years ended December 31, 2017 2016 2015 (i) Net income attributable to Willis Towers Watson $ 568 $ 420 $ 373 Basic weighted-average number of shares outstanding 135 137 68 Dilutive effect of potentially issuable shares 1 1 1 Diluted weighted-average number of shares outstanding 136 138 69 Basic earnings per share $ 4.21 $ 3.07 $ 5.49 Dilutive effect of potentially issuable shares (0.03 ) (0.03 ) (0.08 ) Diluted earnings per share $ 4.18 $ 3.04 $ 5.41 ____________________ (i) Shares outstanding, potentially issuable shares, basic and diluted earnings per share, and the dilutive effect of potentially issuable shares, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split effected on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details. There were no anti-dilutive options for the year ended December 31, 2017. Options to purchase 0.5 million and 0.6 million shares for the years ended December 31, 2016 and 2015 , respectively, were not included in the computation of the dilutive effect of stock options because their effect was anti-dilutive. There were no anti-dilutive RSUs for the years ended December 31, 2017 and 2016. For the year ended December 31, 2015, 0.5 million RSUs were not included in the computation of the dilutive effect of potentially issued shares because their effect was anti-dilutive. The number of options for 2015 has been retroactively adjusted to reflect the reverse stock split on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.

Supplemental Disclosures of Cas

Supplemental Disclosures of Cash Flow Information	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [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: Years Ended December 31, 2017 2016 2015 Supplemental disclosures of cash flow information: Cash payments for income taxes, net $ 203 $ 158 $ 91 Cash payments for interest $ 169 $ 143 $ 126 Cash acquired $ — $ 476 $ 148 Supplemental disclosures of non-cash investing and financing activities: Issuance of shares and assumed awards in connection with the Merger $ — $ 8,723 $ — Fair value of deferred and contingent consideration related to acquisitions $ — $ — $ 204

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	Quarterly Financial Data (Unaudited) Quarterly financial data for 2017 and 2016 were as follows: Three Months Ended March 31, June 30, September 30, December 31, 2017 Total revenues $ 2,319 $ 1,953 $ 1,852 $ 2,078 Total costs of providing services $ 1,856 $ 1,829 $ 1,811 $ 1,968 Income/(loss) from operations $ 463 $ 124 $ 41 $ 110 Net income/(loss) $ 352 $ 41 $ (54 ) $ 253 Net income/(loss) attributable to Willis Towers Watson $ 344 $ 33 $ (54 ) $ 245 Earnings/(loss) per share — Basic $ 2.51 $ 0.24 $ (0.40 ) $ 1.85 — Diluted $ 2.50 $ 0.24 $ (0.40 ) $ 1.84 2016 Total revenues $ 2,234 $ 1,949 $ 1,777 $ 1,927 Total costs of providing services $ 1,908 $ 1,813 $ 1,776 $ 1,839 Income from operations $ 326 $ 136 $ 1 $ 88 Net income/(loss) $ 245 $ 76 $ (31 ) $ 148 Net income/(loss) attributable to Willis Towers Watson $ 238 $ 72 $ (32 ) $ 142 Earnings/(loss) per share — Basic $ 1.76 $ 0.52 $ (0.23 ) $ 1.04 — Diluted $ 1.75 $ 0.51 $ (0.23 ) $ 1.03 During the fourth quarter of 2016, management corrected an error by recording a $103 million benefit from income taxes related to the release of a portion of our U.S. deferred tax valuation allowance. A portion of the correction should have been recorded in each of the three fiscal year 2016 Quarterly Reports on Form 10-Q. Management determined that the error was immaterial to the previously filed 2016 quarterly financial statements and had no impact on prior year financial statements.

Financial Information for Paren

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries	12 Months Ended
	Dec. 31, 2017
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 $837 million senior notes outstanding of which $187 million were issued on September 29, 2009, and $650 million were issued on May 16, 2017. Additionally, Willis North America had $394 million of senior notes issued on March 28, 2007; these were subsequently repaid on March 28, 2017. All direct obligations under the senior notes are jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited, collectively the ‘Other Guarantors’, and with Willis Towers Watson, the ‘Guarantor Companies’. On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis Towers Watson described in Note 22 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson, the Other Guarantors and the Issuer. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 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. On March 15, 2016, $300 million of these senior notes was repaid, leaving $500 million outstanding. These debt securities were issued by Willis Towers Watson (‘WTW Debt Securities’) and are guaranteed by certain of the Company’s subsidiaries. Therefore, the Company is providing the condensed consolidating financial information below. The following wholly owned subsidiaries (directly or indirectly) fully and unconditionally guarantee the WTW Debt Securities on a joint and several basis: Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis North America Inc., Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited (the ‘Guarantors’). On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis North America described in Note 21 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson and the Guarantors. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (

Financial Information for Par28

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Financial Information for Parent Issuer, 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 $837 million senior notes outstanding of which $187 million were issued on September 29, 2009, and $650 million were issued on May 16, 2017. Additionally, Willis North America had $394 million of senior notes issued on March 28, 2007; these were subsequently repaid on March 28, 2017. All direct obligations under the senior notes are jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited, collectively the ‘Other Guarantors’, and with Willis Towers Watson, the ‘Guarantor Companies’. On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis Towers Watson described in Note 22 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson, the Other Guarantors and the Issuer. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 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. On March 15, 2016, $300 million of these senior notes was repaid, leaving $500 million outstanding. These debt securities were issued by Willis Towers Watson (‘WTW Debt Securities’) and are guaranteed by certain of the Company’s subsidiaries. Therefore, the Company is providing the condensed consolidating financial information below. The following wholly owned subsidiaries (directly or indirectly) fully and unconditionally guarantee the WTW Debt Securities on a joint and several basis: Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis North America Inc., Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited (the ‘Guarantors’). On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis North America described in Note 21 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson and the Guarantors. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (

Financial Information for Issue

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Financial Information for Issuer, 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 $837 million senior notes outstanding of which $187 million were issued on September 29, 2009, and $650 million were issued on May 16, 2017. Additionally, Willis North America had $394 million of senior notes issued on March 28, 2007; these were subsequently repaid on March 28, 2017. All direct obligations under the senior notes are jointly and severally, irrevocably and fully and unconditionally guaranteed by Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited, collectively the ‘Other Guarantors’, and with Willis Towers Watson, the ‘Guarantor Companies’. On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis Towers Watson described in Note 22 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson, the Other Guarantors and the Issuer. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 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. On March 15, 2016, $300 million of these senior notes was repaid, leaving $500 million outstanding. These debt securities were issued by Willis Towers Watson (‘WTW Debt Securities’) and are guaranteed by certain of the Company’s subsidiaries. Therefore, the Company is providing the condensed consolidating financial information below. The following wholly owned subsidiaries (directly or indirectly) fully and unconditionally guarantee the WTW Debt Securities on a joint and several basis: Willis Netherlands Holdings B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis North America Inc., Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson UK Holdings Limited (the ‘Guarantors’). On August 11, 2017 a newly formed entity, Willis Towers Watson UK Holdings Limited, became the successor to, and assumed all guarantees of, WTW Bermuda Holdings Ltd. under the outstanding indentures for the senior notes described above. As both entities are direct subsidiaries of TA I Limited, and sub-consolidate within the ‘Other Guarantors’ columns of the financial statements presented herein, there is no significant impact on the condensed consolidating financial statements from what has previously been disclosed. The guarantor structure described above differs from the guarantor structure associated with the senior notes issued by Willis North America described in Note 21 and the guarantor structure associated with the senior notes and revolving credit facility issued by Trinity Acquisition plc described in Note 23 . Presented below is condensed consolidating financial information for: (i) Willis Towers Watson, 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 condensed consolidating balance sheets of Willis Towers Watson and the Guarantors. Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (

Basis of Basis of Presentation,

Basis of Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation — The accompanying consolidated financial statements include the accounts of Willis Towers Watson and those of our majority-owned and controlled subsidiaries. Intercompany accounts and transactions have been eliminated. We determine whether we have a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (‘VIE’). Variable interest entities are entities that lack one or more of the characteristics of a voting interest entity and therefore require a different approach in determining which party involved with the VIE should consolidate the entity. With a VIE, either the entity does not have sufficient equity at risk to finance its activities without additional subordinated financial support from other parties, or the equity holders, as a group, do not have the power to direct the activities that most significantly impact its financial performance, the obligation to absorb expected losses of the entity, or the right to receive the expected residual returns of the entity. The entity that has a controlling financial interest in a VIE is referred to as the primary beneficiary and is required to consolidate the VIE. Voting interest entities are entities that have sufficient equity and provide equity investors voting rights that give them the power to make significant decisions related to the entity’s operations. The usual condition for a controlling financial interest in a voting interest entity is ownership of a majority voting interest. Accordingly, we consolidate our voting interest entity investments in which we hold, directly or indirectly, more than 50% of the voting rights.
Use of Estimates	Use of Estimates — These consolidated financial statements conform to accounting principles generally accepted in the United States of America (‘U.S. GAAP’), which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Our estimates, judgments and assumptions are continually evaluated based on available information and experience. Because of the use of estimates inherent in the financial reporting process, actual results could differ from those estimates. Estimates are used when accounting for revenue recognition, the selection of useful lives of fixed and intangible assets, impairment testing, valuation of billed and unbilled receivables from clients, discretionary compensation, income taxes, pension assumptions, incurred but not reported claims, legal reserves and goodwill and intangible assets.
Going Concern	Going Concern — Management evaluates at each annual and interim period whether there are conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. Management’s evaluation is based on relevant conditions and events that are known and reasonably knowable at the date that the consolidated financial statements are issued. Management has concluded that there are no conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date of these financial statements.
Investments in Associates	The Company periodically reviews its investments in associates for which fair value is less than cost to determine if the decline in value is other than temporary. If the decline in value is judged to be other than temporary, the cost basis of the investment is written down to fair value. The amount of any write-down is included in the consolidated statements of comprehensive income.
Cash and Cash Equivalents	Cash and Cash Equivalents — Cash and cash equivalents primarily consist of time deposits with original maturities of 90 days or less. Willis Limited, our U.K. brokerage subsidiary regulated by the Financial Conduct Authority, is currently required to maintain $140 million in unencumbered and available financial resources, of which at least $79 million
Fiduciary Assets and Liabilities	Fiduciary Assets and Liabilities — Fiduciary funds represent unremitted premiums received from insureds and unremitted claims or refunds received from insurers. Fiduciary funds are generally required to be kept in certain regulated bank accounts subject to guidelines which emphasize capital preservation and liquidity. Such funds are not available to service the Company’s debt or for other corporate purposes. Notwithstanding the legal relationships with insureds and insurers, the Company is entitled to retain investment income earned on fiduciary funds in accordance with industry custom and practice and, in some cases, as supported by agreements with insureds. The period for which the Company holds such funds is dependent upon the date the insured remits the payment of the premium to the Company, or the date the Company receives refunds from the insurers, and the date the Company is required to forward such payment to the insurer, or insured, respectively. In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. Such advances are made from fiduciary funds and are reflected in the consolidated balance sheets as fiduciary assets. Fiduciary liabilities represent the obligations to remit fiduciary funds and fiduciary receivables to insurers or insureds. Certain of our health and welfare benefits administration outsourcing agreements require us to hold funds on behalf of clients to pay obligations on their behalf. These amounts are included in fiduciary assets and fiduciary liabilities on the consolidated balance sheets.
Accounts Receivable	Accounts Receivable — Accounts receivable includes both billed and unbilled receivables and is stated at estimated net realizable values. Provision for billed receivables is recorded, when necessary, in an amount considered by management to be sufficient to meet probable future losses related to uncollectible accounts. Accrued and unbilled receivables are stated at net realizable value which includes an allowance for accrued and unbillable amounts.
Income Taxes	Income Taxes — The Company recognizes deferred tax assets and liabilities for the estimated future tax consequences of events attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating and capital loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which the differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of changes in tax rates is recognized in the consolidated statement of comprehensive income in the period in which the change is enacted. Deferred tax assets are reduced through the establishment of a valuation allowance at such time as, based on available evidence, it is more likely than not that the deferred tax assets will not be realized. The Company adjusts valuation allowances to measure deferred tax assets at the amounts considered realizable in future periods if the Company’s facts and assumptions change. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and the results of recent financial operations. We place more reliance on evidence that is objectively verifiable. Positions taken in the Company’s tax returns may be subject to challenge by the taxing authorities upon examination. The Company recognizes the benefit of uncertain tax positions in the financial statements when it is more likely than not that the position will be sustained on the basis of the technical merits of the position assuming the tax authorities have full knowledge of the position and all relevant facts. Recognition also occurs upon either the lapse of the relevant statute of limitations, or when positions are effectively settled. The benefit recognized is the largest amount of tax benefit that is greater than 50 percent likely to be realized on settlement with the tax authority. The Company adjusts its recognition of uncertain tax benefits in the period in which new information is available impacting either the recognition or measurement of its uncertain tax positions. Such adjustments are reflected as increases or decreases to income taxes in the period in which they are determined. The Company recognizes interest and penalties relating to unrecognized tax benefits within income taxes.
Foreign Currency	Foreign Currency — Transactions in currencies other than the functional currency of the entity are recorded at the rates of exchange prevailing at the date of the transaction. Monetary assets and liabilities in currencies other than the functional currency are translated at the rates of exchange prevailing at the balance sheet date and the related transaction gains and losses are reported as income or expense in the consolidated statements of comprehensive income. Certain intercompany loans are determined to be of a long-term investment nature. The Company records transaction gains and losses from re-measuring such loans as other comprehensive income in the consolidated statements of comprehensive income. Upon consolidation, the results of operations of subsidiaries and associates whose functional currency is other than the U.S. dollar are translated into U.S. dollars at the average exchange rates and assets and liabilities are translated at year-end exchange rates. Translation adjustments are presented as a separate component of other comprehensive income in the financial statements and are included in net income only upon sale or liquidation of the underlying foreign subsidiary or associated company.
Derivatives	Derivatives — The Company uses derivative financial instruments for other than trading purposes to alter the risk profile of an existing underlying exposure. Interest rate swaps have been used to manage interest risk exposures. Forward foreign currency exchange contracts are used to manage currency exposures arising from future income and expenses. The fair values of derivative contracts are recorded in other assets and other liabilities. The effective portions of changes in the fair value of derivatives that qualify for hedge accounting as cash flow hedges are recorded in other comprehensive income. Amounts are reclassified from other comprehensive income into earnings when the hedged exposure affects earnings. If the derivative is designated and qualifies as an effective fair value hedge, the changes in the fair value of the derivative and of the hedged item associated with the hedged risk are both recognized in earnings. The amount of hedge ineffectiveness recognized in earnings is based on the extent to which an offset between the fair value of the derivative and hedged item is not achieved. Changes in fair value of derivatives that do not qualify for hedge accounting, together with any hedge ineffectiveness on those that do qualify, are recorded in other operating expenses or interest expense as appropriate. The Company evaluates whether its contracts include clauses or conditions which would be required to be separately accounted for at fair value as embedded derivatives. See
Commitments, Contingencies and Accrued Liabilities	Commitments, Contingencies and Provisions for Liabilities — The Company establishes provisions against various actual and potential claims, lawsuits and other proceedings relating principally to alleged errors and omissions in the ordinary course of business. Such provisions cover claims that have been reported but not paid and also unasserted claims and related legal fees. These provisions are established based on actuarial estimates together with individual case reviews and are believed to be adequate in light of current information and legal advice. In certain cases, where a range of loss exists, we accrue the minimum amount in the range if no amount within the range is a better estimate than any other amount. To the extent such losses can be recovered under the Company’s insurance programs, estimated recoveries are recorded when losses for insured events are recognized and the recoveries are likely to be realized. Significant management judgment is required to estimate the amounts of such unasserted claims and the related insurance recoveries. The Company analyzes its litigation exposure based on available information, including consultation with outside counsel handling the defense of these matters, to assess its potential liability. These contingent liabilities are not discounted.
Share-Based Compensation	Share-Based Compensation — The Company has equity-based compensation plans that provide for grants of restricted stock units and stock options to employees and non-employee directors of the Company. The Company expenses equity-based compensation, which is included in Salaries and benefits in the consolidated statements of comprehensive income, primarily on a straight-line basis over the requisite service period. The significant assumptions underlying our expense calculations include the fair value of the award on the date of grant, the estimated achievement of any performance targets and estimated forfeiture rates. The awards under equity-based compensation are classified as equity and included as a component of equity on the Company’s consolidated balance sheets, as the ultimate payment of such awards will not be achieved through use of the Company’s cash or other assets.
Fixed Assets	Fixed Assets — Fixed assets are stated at cost less accumulated depreciation. Expenditures for improvements are capitalized; repairs and maintenance are charged to expense as incurred. Depreciation is computed primarily using the straight-line method based on the estimated useful lives of assets. Depreciation on internally developed software is amortized over the estimated useful life of the asset ranging from 3 to 10 years. Buildings include assets held under capital leases and are depreciated over the lesser of 50 years, the asset lives or the lease terms. Depreciation on leasehold improvements is calculated over the lesser of the useful lives of the assets or the remaining lease terms. Depreciation on furniture and equipment is calculated based on a range of 3 to 10 years. Land is not depreciated. Long-lived assets are tested for recoverability whenever events or changes in circumstance indicate that their carrying amounts may not be recoverable. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. Recoverability is determined based on the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group. Long-lived assets and certain identifiable intangible assets to be disposed of are reported at the lower of carrying amount or fair value less cost to sell.
Operating Leases	Operating Leases —Rentals payable on operating leases are charged on a straight-line basis to Other operating expenses in the consolidated statements of comprehensive income over the lease term.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets — In applying the acquisition method of accounting for business combinations, amounts assigned to identifiable assets and liabilities acquired were based on estimated fair values as of the date of acquisition, with the remainder recorded as goodwill. Intangible assets are initially valued at fair value using generally accepted valuation methods appropriate for the type of intangible asset. Intangible assets with definite lives are amortized over their estimated useful lives and are reviewed for impairment if indicators of impairment arise. Intangible assets with indefinite lives are tested for impairment annually as of October 1, and whenever indicators of impairment exist. The fair values of intangible assets are compared with their carrying values, and an impairment loss would be recognized for the amount by which a carrying amount exceeds its fair value. Acquired intangible assets are amortized over the following periods: Amortization basis Expected life (years) Client relationships In line with underlying cash flows 5 to 20 Software In line with underlying cash flows or straight-line basis 4 to 7 Product In line with underlying cash flows 17.5 Trademark and trade name Straight-line basis 14 to 25 Favorable agreements Straight-line basis 7 Management contracts Straight-line basis 18 Goodwill is tested for impairment annually as of October 1, and whenever indicators of impairment exist. Goodwill is tested at the reporting unit level, and the Company had nine reporting units as of October 1, 2017. In the first step of the impairment test, the fair value of each reporting unit is compared with its carrying value, including goodwill. If the carrying value of a reporting unit exceeds its fair value, the amount of an impairment loss, if any, is calculated in the second step of the impairment test by comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. The Company’s goodwill impairment tests for the years ended December 31, 2017 and 2016 have not resulted in any impairment charges.
Pensions	Pensions — The Company has multiple defined benefit pension and defined contribution plans. The net periodic cost of the Company’s defined benefit plans are measured on an actuarial basis using various methods and actuarial assumptions. The most significant assumptions are the discount rates (calculated from the 2016 fiscal year and forward using the granular approach to calculating service and interest cost) and the expected long-term rates of return on plan assets. Other material assumptions include rates of participant mortality, the expected long-term rates of compensation and pension increases and rates of employee termination. Gains and losses occur when actual experience differs from actuarial assumptions. If such gains or losses exceed ten percent of the greater of plan assets or plan liabilities, the Company amortizes those gains or losses over the average remaining service period or average remaining life expectancy, as appropriate, of the plan participan ts. In accordance with U.S. GAAP, the Company records on its consolidated balance sheets the funded status of its pension plans based on the projected benefit obligation. Contributions to the Company’s defined contribution plans are recognized as incurred. Differences between contributions payable in the year and contributions actually paid are shown as either other assets or other liabilities in the consolidated balance sheets.
Revenue Recognition	Revenue Recognition — Revenues include insurance commissions, fees in lieu of commission, fees for consulting services rendered, hosted and delivered software, survey sales, interest and other income. Revenue recognized in excess of billings is recorded as unbilled accounts receivable. Cash collections in excess of revenue recognized are recorded as deferred revenue until the revenue recognition criteria are met. Client reimbursable expenses, including those relating to travel, other out-of-pocket expenses and any third-party costs, are included in revenue, and an equivalent amount of reimbursable expenses is included in other operating expenses as a cost of revenue. Taxes collected from customers and remitted to government authorities are recorded net and are excluded from revenue. Commissions and fees Commissions revenue. Brokerage commissions and fees negotiated in lieu of commissions are recognized at the later of the policy inception date or when the policy placement is complete. In situations in which our fees are not fixed and determinable due to the uncertainty of the commission fee per policy, we recognize revenue as the fees are determined. Commissions on additional premiums and adjustments are recognized when approved by or agreed between the parties and collectability is reasonably assured. Consulting revenue. The majority of our consulting revenues consists of fees earned from providing consulting services. We recognize revenues from these consulting engagements when hours are worked, either on a time-and-expense basis or on a fixed-fee basis, depending on the terms and conditions defined at the inception of an engagement with a client. We have engagement letters with our clients that specify the terms and conditions upon which the engagements are based. These terms and conditions can only be changed upon agreement by both parties. Individual billing rates are principally based on a multiple of salary and compensation costs. Revenues for fixed-fee arrangements are based upon the proportional performance method to the extent estimates can be made of the remaining work required under the arrangement. If we do not have sufficient information to estimate proportional performance, we recognize the fees straight-line over the contract period. We typically have four types of fixed-fee arrangements: annual recurring projects, projects of a short duration, stand-ready obligations and non-recurring system projects. • Annual recurring projects and projects of short duration. These projects are typically straightforward and highly predictable in nature. As a result, the project manager and financial staff are able to identify, as the project status is reviewed and bills are prepared monthly, the occasions when cost overruns could lead to the recording of a loss accrual. • Stand-ready obligations. Where we are entitled to fees (whether fixed or variable based on assets under management or a per-participant per-month basis) regardless of the hours, we generally recognize this revenue on either a straight-line basis or as the variable fees are calculated. • Non-recurring system projects. These projects are longer in duration and subject to more changes in scope as the project progresses. Certain software or outsourced administration contracts generally provide that if the client terminates a contract, we are entitled to an additional payment for services performed through termination designed to recover our up-front cost of implementation. Revenue recognition for fixed-fee engagements is affected by a number of factors that change the estimated amount of work required to complete the project such as changes in scope, the staffing on the engagement and/or the level of client participation. The periodic engagement evaluations require us to make judgments and estimates regarding the overall profitability and stage of project completion that, in turn, affect how we recognize revenue. We recognize a loss on an engagement when estimated revenues to be received for that engagement are less than the total estimated costs associated with the engagement. Losses are recognized in the period in which the loss becomes probable and the amount of the loss is reasonably estimable. Hosted software. We have developed various software programs and technologies that we provide to clients in connection with consulting services. In most instances, such software is hosted and maintained by us and ownership of the technology and rights to the related code remain with us. We defer costs for software developed to be utilized in providing services to a client, but for which the client does not have the contractual right to take possession, during the implementation stage. We recognize these deferred costs from the go live date, signaling the end of the implementation stage, until the end of the initial term of the contract with the client. We determined that the system implementation and customized ongoing administrative services are one combined service. Revenue is recognized over the service period, after the go live date, on a straight-line basis. As a result, we do not recognize revenue during the implementation phase of an engagement. Delivered software. We deliver software under arrangements with clients who take possession of our software. The maintenance associated with the initial software fees is a fixed percentage which enables us to determine the stand-alone value of the delivered software separate from the maintenance. We recognize the initial software fees as software is delivered to the client, and we recognize the maintenance fees ratably over the contract period based on each element’s relative fair value. For software arrangements in which initial fees are received in connection with mandatory maintenance for the initial software license to remain active, we determined that the initial maintenance period is substantive. Therefore, we recognize the fees for the initial license and maintenance bundle ratably over the initial contract term, which is generally one year . Each subsequent renewal fee is recognized ratably over the contractually stated renewal period. Surveys. We collect, analyze and compile data in the form of surveys for our clients who have the option of participating in the survey. The surveys are published online via a web tool that provides simplistic functionality. We have determined that the web tool is inconsequential to the overall arrangement. We record the survey revenues when the results are delivered online and made available to our clients who have a contractual right to the data. If the data is updated more frequently than annually, we recognize the survey revenues ratably over the contractually stated period. Interest and other income Interest income. Interest income is recognized as earned. Other Income. Other income includes gains on disposal of intangible assets, which primarily arise from settlements through enforcing non-compete agreements in the event of losing accounts through producer defection or the disposal of books of business.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Not yet adopted In May 2014, the Financial Accounting Standards Board (‘FASB’) issued Accounting Standard Update (‘ASU’) No. 2014-09, Revenue From Contracts With Customers . The new standard supersedes most current revenue recognition guidance and eliminates most industry-specific guidance. The ASU is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. Additional ASUs have since been issued which provide further guidance, examples and technical corrections for the implementation of ASU No. 2014-09. All related guidance has been codified into, and is now known as, Accounting Standards Codification (‘ASC’) 606. The guidance was effective for the Company at the beginning of its 2018 fiscal year, with early adoption permitted. As a result of analyzing our various revenue streams to determine the full impact this standard will have on our revenue recognition, cost deferral, systems and processes, the Company has determined the following: • The Company has adopted the standard using the modified retrospective approach on January 1, 2018, and has applied the new standard only to contracts that are not completed as of the transition date. • Certain revenue streams have accelerated revenue recognition timing. In particular, the revenue recognition for our Individual Marketplace (formerly Retiree & Access Exchanges) has moved from monthly ratable recognition over the policy period, to the recognition upon placement of the policy. Consequently, the Company will now recognize the majority of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. Therefore, at the adoption date, we have reflected an adjustment to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, the revenue recognition for proportional treaty broking commissions has moved from recognition upon the receipt of the monthly or quarterly statements, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we will reflect an adjustment to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior. • Revenue recognition for certain other revenue streams has changed from recognizing revenue at a point in time to recognizing revenue over time. Specifically, certain arrangements in our Health and Benefits broking business will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or annual in nature and are considered complete as of the transition date. Therefore, no retained earnings adjustment is required. • Our accounting for deferred costs will change. First, for those portions of the business that previously deferred costs (related to system implementation activities), the length of time over which we amortize those costs will extend to a longer estimated contract term. For 2017 calendar year and prior, these costs were amortized over a typical period of 3 - 5 years in accordance with the initial stated terms of the customer agreements. Second, other types of arrangements with associated costs now meet the criteria for cost deferral under ASC 606. This guidance will now apply to our broking arrangements and certain consulting engagements. We have calculated a retained earnings adjustment to reflect this cumulative change for contracts not complete as of the transition date. Although we are still finalizing the impact to retained earnings as of January 1, 2018, we expect the total range of adjustment, before the effect of taxes, to be an increase to retained earnings of $375 million to $475 million . In preparation for the additional disclosure requirements that will be included in our quarterly and annual filings beginning with our calendar year 2018 first quarter filing, we have implemented additional tools and technologies to support our revenue recognition and data collection processes. In February 2016, the FASB issued ASU No. 2016-02, Leases , which requires a lessee to recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. The ASU becomes effective for the Company at the beginning of its 2019 calendar year, at which time the Company will adopt it, although early adoption is permitted. While the Company continues to assess the impact of the ASU to its consolidated financial statements, the majority of its leases are currently considered operating leases and will be capitalized as a lease asset on its balance sheet with a related lease liability for the obligated lease payments. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments , which amends guidance on presentation and classification of eight specific cash flow issues with the objective of reducing diversity in practice. The ASU became effective for the Company at the beginning of its 2018 calendar year, at which time the Company adopted it. Consistent with the transition guidance, the Company will reflect the new guidance as of the beginning of 2018 in our first quarter Form 10-Q. The Company is still assessing the impact of this ASU, but it believes the impact on its financial statements will be immaterial. In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment , which simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. In computing the implied fair value of goodwill under Step 2, current U.S. GAAP requires the performance of procedures to determine the fair value at the impairment testing date of assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, the amendments under this ASU require the goodwill impairment test to be performed by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The ASU becomes effective for the Company on January 1, 2020. The amendments in this ASU should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017, and the Company is still evaluating when to adopt this ASU. The Company does not expect an immediate impact to its consolidated financial statements upon adopting this ASU since the most recent Step 1 goodwill impairment test resulted in fair values in excess of carrying values for all reporting units at October 1, 2017. In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , which requires entities to (1) disaggregate the current service-cost component from the other components of net benefit cost (the ‘other components’) and present it in the income statement with other current compensation costs for related employees and (2) present the other components elsewhere in the income statement and outside of income from operations if that subtotal is presented. In addition, the ASU requires entities to disclose the income statement lines that contain the other components if they are not presented or included in appropriately described separate lines. The ASU became effective for the Company on January 1, 2018, at which time the Company adopted it, and will apply the standard retrospectively beginning in its 2018 first quarter Form 10-Q. The Company has determined that, while the classification of some components of net benefit cost will change within the accompanying consolidated statement of comprehensive income, there is no material impact on its consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Stock Compensation - Scope of Modification Accounting , which provides guidance on which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The ASU requires that an entity should account for the effects of a modification unless the fair value (or calculated value or intrinsic value, if used), vesting conditions and classification (as equity or liability) of the modified award are all the same as for the original award immediately before the modification. The ASU became effective for the Company on January 1, 2018, at which time the Company adopted it, and should be applied prospectively to an award modified on or after the adoption date. There is no immediate impact to the accompanying consolidated financial statements, until such time as an award may be modified in 2018 or forward. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities , which provides amendments under six specific objectives to better align risk management activities and financial reporting, and to simplify disclosure, presentation, hedging and the testing and measurement of ineffectiveness. The ASU becomes effective for the Company on January 1, 2019. Early adoption is permitted, and any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. The Company is currently assessing when it will adopt this standard, and the impact that this standard will have on its consolidated financial statements. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allows for a reclassification from accumulated other comprehensive income to retained earnings for ‘stranded’ tax effects (those tax effects of items within accumulated other comprehensive income resulting from the historical corporate income tax rate reduction) resulting from the Tax Cuts and Jobs Act. The amendments within this ASU also require certain disclosures about stranded tax effects. The ASU becomes effective for the Company on January 1, 2019. Early adoption is permitted, and any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. The Company is currently assessing when it will adopt this standard, and the impact that this standard will have on its consolidated financial statements. Adopted In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation , which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The ASU became effective for the Company on January 1, 2017. In accordance with the prospective adoption of the recognition of excess tax benefits and deficiencies in the consolidated statements of comprehensive income, we recognized a $7 million tax benefit in provision for income taxes during the year ended December 31, 2017 . In addition, we elected to prospectively adopt the amendment to present excess tax benefits on share-based compensation as an operating activity, resulting in the recognition of a $7 million excess tax benefit as an operating activity in the consolidated statement of cash flows for the year ended December 31, 2017 . We elected to continue to estimate expected forfeitures. We also retrospectively adopted the amendment to present cash payments to tax authorities in connection with shares withheld to meet statutory tax withholding requirements as a financing activity. As a result, these $13 million and $1 million uses of cash were reclassified from net cash from operating activities to net cash used in financing activities in the consolidated statement of cash flows for the years ended December 31, 2016 , and December 31, 2015 , respectively. In October 2016, the FASB issued ASU No. 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory , which amends guidance regarding the recognition of current and deferred income taxes for intra-entity asset transfers. Current U.S. GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. The ASU states that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments in this ASU should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company elected to early adopt this standard on January 1, 2017, and recorded a cumulative reduction to retained earnings of $3 million .

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Disclosures (Policies)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	The Company has categorized its assets and liabilities that are measured at fair value on a recurring and non-recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows: • Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets; • Level 2: refers to fair values estimated using observable market based inputs or unobservable inputs that are corroborated by market data; and • Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data. The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments: • Available-for-sale securities are classified as Level 1 because we use quoted market prices in determining the fair value of these securities. • Market values for our derivative instruments 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 observable information about the current interest rate environment or current foreign currency forward rates. Such financial instruments are classified as Level 2 in the fair value hierarchy. • Contingent consideration payable is classified as Level 3, and we estimate fair value based on the likelihood and timing of achieving the relevant milestones of each arrangement, applying a probability assessment to each of the potential outcomes, and discounting the probability-weighted payout. Typically, milestones are based on revenue or EBITDA growth for the acquired business.

Basis of Basis of Presentatio32

Basis of Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	Acquired intangible assets are amortized over the following periods: Amortization basis Expected life (years) Client relationships In line with underlying cash flows 5 to 20 Software In line with underlying cash flows or straight-line basis 4 to 7 Product In line with underlying cash flows 17.5 Trademark and trade name Straight-line basis 14 to 25 Favorable agreements Straight-line basis 7 Management contracts Straight-line basis 18 The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 339 20 Software and other intangibles Cost of reproduction Straight-line basis 66 5 Trade name Relief from royalty Straight-line basis 35 14 $ 440 The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 2,221 15.0 Software - income approach Multiple period excess earnings In line with underlying cash flows or straight-line basis 567 6.4 Software - cost approach Cost of reproduction Straight-line basis 108 4.9 Product Multiple period excess earnings In line with underlying cash flows 42 17.5 IPR&D (i) Multiple period excess earnings or cost of reproduction n/a 39 n/a Trade name Relief from royalty Straight-line basis 1,003 25.0 Favorable lease agreements Market approach Straight-line basis 11 6.5 $ 3,991 ____________________ (i) Represents individual in-process research and development (‘IPR&D’) software components not placed into service as of the acquisition date. These assets were subsequently placed into service during the three months ended March 31, 2017, were reclassified into finite-lived software intangible assets, and are being amortized in line with underlying cash flows or on a straight-line basis.

Merger, Acquisitions and Dive33

Merger, Acquisitions and Divestitures Merger, Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Preliminary Calculation of Aggregate Merger Consideration	The table below presents the final calculation of aggregate Merger consideration . January 4, 2016 Number of shares of Towers Watson common stock outstanding as of January 4, 2016 69 million Exchange ratio 2.6490 Number of Willis Group Holdings shares issued (prior to reverse stock split) 184 million Willis Group Holdings price per share on January 4, 2016 $ 47.18 Fair value of 184 million Willis ordinary shares $ 8,686 Value of equity awards assumed 37 Aggregate Merger consideration $ 8,723
Schedule of Fair Values of the Identifiable Assets Acquired and Liabilities Assumed	A summary of the fair values of the identifiable assets acquired, and liabilities assumed, of Towers Watson at January 4, 2016 are summarized in the following table. January 4, 2016 Cash and cash equivalents $ 476 Accounts receivable, net 825 Other current assets 82 Fixed assets, net 204 Goodwill 6,783 Intangible assets 3,991 Pension benefits assets 67 Other non-current assets 115 Deferred tax liabilities (1,151 ) Liability for pension benefits (923 ) Other current liabilities (i) (667 ) Other non-current liabilities (ii) (331 ) Long term debt, including current portion (iii) (740 ) Net assets acquired 8,731 Non-controlling interests acquired (8 ) Allocated aggregate Merger consideration $ 8,723 ____________________ (i) Includes $348 million in accounts payable, accrued liabilities and deferred revenue, $308 million in employee-related liabilities and $11 million in other current liabilities. (ii) Includes acquired contingent liabilities of $ 242 million . See Note 13 — Commitments and Contingencies for a discussion of our material acquired contingencies related to Legacy Towers Watson. (iii) Represents both debt due upon change of control of $400 million borrowed under Towers Watson’s term loan ( $188 million ) and revolving credit facility ( $212 million ) and a draw down under a new term loan of $340 million . The $400 million debt was repaid by Willis’ borrowings under the 1-year term loan facility on January 4, 2016. The $340 million new term loan partially funded the $694 million Towers Watson pre-merger special dividend. The following table presents the Company’s allocation of the purchase price to the assets acquired and liabilities assumed based on their fair values: December 29, 2015 Cash and cash equivalents $ 87 Fiduciary assets 625 Accounts receivable, net 89 Goodwill 584 Intangible assets 440 Other assets 56 Fiduciary liabilities (625 ) Deferred revenue and accrued expenses (80 ) Short and long-term debt (80 ) Net deferred tax liabilities (87 ) Other liabilities (179 ) Net assets acquired 830 Decrease in paid-in capital for purchase of non-controlling interest 43 Non-controlling interest acquired (40 ) Purchase price allocation $ 833
Schedule of Acquired Intangible Assets	Acquired intangible assets are amortized over the following periods: Amortization basis Expected life (years) Client relationships In line with underlying cash flows 5 to 20 Software In line with underlying cash flows or straight-line basis 4 to 7 Product In line with underlying cash flows 17.5 Trademark and trade name Straight-line basis 14 to 25 Favorable agreements Straight-line basis 7 Management contracts Straight-line basis 18 The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 339 20 Software and other intangibles Cost of reproduction Straight-line basis 66 5 Trade name Relief from royalty Straight-line basis 35 14 $ 440 The acquired intangible assets are attributable to the following categories: Valuation Methodology Amortization Basis Fair Value Expected Life (Years) Customer relationships Multiple period excess earnings In line with underlying cash flows $ 2,221 15.0 Software - income approach Multiple period excess earnings In line with underlying cash flows or straight-line basis 567 6.4 Software - cost approach Cost of reproduction Straight-line basis 108 4.9 Product Multiple period excess earnings In line with underlying cash flows 42 17.5 IPR&D (i) Multiple period excess earnings or cost of reproduction n/a 39 n/a Trade name Relief from royalty Straight-line basis 1,003 25.0 Favorable lease agreements Market approach Straight-line basis 11 6.5 $ 3,991 ____________________ (i) Represents individual in-process research and development (‘IPR&D’) software components not placed into service as of the acquisition date. These assets were subsequently placed into service during the three months ended March 31, 2017, were reclassified into finite-lived software intangible assets, and are being amortized in line with underlying cash flows or on a straight-line basis.
Unaudited Pro Forma Financial Information	The following pro forma financial information is unaudited and is intended to reflect the impact of the Merger on Willis Towers Watson’s consolidated financial statements as if the Merger had taken place on January 1, 2015 and presents the results of operations of Willis Towers Watson based on the historical financial statements of Willis and Towers Watson after giving effect to the Merger and pro forma adjustments. Pro forma adjustments are included only to the extent they are (i) directly attributable to the Merger, (ii) factually supportable and (iii) with respect to the consolidated statement of comprehensive income, expected to have a continuing impact on the combined results. The accompanying unaudited pro forma financial information is presented for illustrative purposes only and has not been adjusted to give effect to certain expected financial benefits of the Merger, such as revenue synergies, tax savings and cost synergies, or the anticipated costs to achieve these benefits, including the cost of integration activities. The unaudited pro forma results are not indicative of what would have occurred had the Merger taken place on the indicated date. Years ended December 31, Pro Forma As reported (Unaudited) 2016 2015 Total revenues $ 7,887 $ 7,492 Net income attributable to Willis Towers Watson $ 420 $ 640 Diluted earnings per share $ 3.04 $ 4.64

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]	The table below presents segment commissions and fees, segment interest and other income, segment revenues, and segment operating income for our reportable segments for the years ended December 31, 2017, 2016, and 2015 . Years ended December 31, HCB CRB IRR BDA Total 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Segment commissions and fees $ 3,163 $ 3,100 $ 583 $ 2,625 $ 2,519 $ 2,332 $ 1,505 $ 1,475 $ 895 $ 729 $ 652 $ — $ 8,022 $ 7,746 $ 3,810 Segment interest and other income 29 17 1 23 28 17 30 59 1 — 2 — 82 106 19 Segment revenues $ 3,192 $ 3,117 $ 584 $ 2,648 $ 2,547 $ 2,349 $ 1,535 $ 1,534 $ 896 $ 729 $ 654 $ — $ 8,104 $ 7,852 $ 3,829 Segment operating income $ 781 $ 728 $ 119 $ 488 $ 463 $ 457 $ 365 $ 383 $ 207 $ 152 $ 119 $ — $ 1,786 $ 1,693 $ 783
Net Operating Income of the Reported Segments	The table below presents a reconciliation of the information reported by segment to the consolidated amounts reported for the years ended December 31, 2017, 2016, and 2015 , respectively: Years ended December 31, 2017 2016 2015 Revenues: Total segment revenues $ 8,104 $ 7,852 $ 3,829 Fair value adjustment to deferred revenue — (58 ) — Reimbursable expenses and other 98 93 — Total revenues $ 8,202 $ 7,887 $ 3,829 Total segment operating income $ 1,786 $ 1,693 $ 783 Fair value adjustment for deferred revenue — (58 ) — Amortization (581 ) (591 ) (76 ) Restructuring costs (132 ) (193 ) (126 ) Transaction and integration expenses (i) (269 ) (177 ) (73 ) Provision for Stanford and other significant litigation (11 ) (50 ) (70 ) Pension settlement and curtailment gains and losses (36 ) — — Unallocated, net (ii) (19 ) (73 ) (11 ) Income from operations 738 551 427 Interest expense 188 184 142 Other expense/(income), net 61 27 (55 ) Income from operations before income taxes and interest in earnings of associates $ 489 $ 340 $ 340 ____________________ (i) Includes transaction and integration expenses related to the Merger and the acquisition of Gras Savoye. (ii) Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.
Revenue and Long-lived Assets by Geographical Areas	Below are our revenues and long-lived assets for Ireland, our country of domicile, countries with significant concentrations, and all other foreign countries for each of the years ended December 31, 2017 , 2016 and 2015 : Revenues Long-Lived Assets (i) 2017 2016 2015 2017 2016 2015 Ireland $ 107 $ 92 $ 64 $ 127 $ 114 $ 124 United States 3,821 3,395 1,597 9,988 11,400 1,759 United Kingdom 1,815 2,236 1,055 3,173 2,431 2,426 Rest of World 2,459 2,164 1,113 3,263 2,466 1,951 Total Foreign Countries 8,095 7,795 3,765 16,424 16,297 6,136 $ 8,202 $ 7,887 $ 3,829 $ 16,551 $ 16,411 $ 6,260 ____________________ (i) Long-Lived Assets do not include deferred tax assets.

Restructuring Costs (Tables)

Restructuring Costs (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Analysis of the Cost for Restructuring	An analysis of total restructuring costs recognized in the consolidated statements of comprehensive income, and the costs by segment, and costs attributable to corporate functions, for the years ended December 31, 2017 , 2016 and 2015 are as follows: HCB CRB IRR BDA Corporate Total Year ended December 31, 2017 Termination benefits $ — $ 25 $ 4 $ — $ 17 $ 46 Professional services and other (i) 3 63 6 — 14 86 Total $ 3 $ 88 $ 10 $ — $ 31 $ 132 Year ended December 31, 2016 Termination benefits $ 33 $ 26 $ 6 $ 1 $ 2 $ 68 Professional services and other (i) 4 81 4 — 36 125 Total $ 37 $ 107 $ 10 $ 1 $ 38 $ 193 Year ended December 31, 2015 Termination benefits $ 2 $ 24 $ 7 $ — $ 3 $ 36 Professional services and other (i) 1 57 2 — 30 90 Total $ 3 $ 81 $ 9 $ — $ 33 $ 126 ___________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs. Restructuring costs related to the Business Restructuring Program for the year ended December 31, 2016 by segment are as follows: HCB CRB IRR BDA Corporate Total (in millions) 2016 Termination benefits $ 32 $ 8 $ 3 $ 1 $ 1 $ 45 Professional services and other (i) 3 — — — — 3 Total $ 35 $ 8 $ 3 $ 1 $ 1 $ 48 ____________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program. An analysis of the total cumulative restructuring costs recognized for the Operational Improvement Program from its commencement to December 31, 2017 by segment is as follows: HCB CRB IRR BDA Corporate Total 2014 Termination benefits $ — $ 15 $ 1 $ — $ — $ 16 Professional services and other (i) — 3 — — 17 20 2015 Termination benefits $ 2 $ 24 $ 7 $ — $ 3 $ 36 Professional services and other (i) 1 57 2 — 30 90 2016 Termination benefits $ 1 $ 18 $ 3 $ — $ 1 $ 23 Professional services and other (i) 1 81 4 — 36 122 2017 Termination benefits $ — $ 25 $ 4 $ — $ 19 $ 48 Professional services and other (i) 3 63 6 — 14 86 Total Termination benefits $ 3 $ 82 $ 15 $ — $ 23 $ 123 Professional services and other (i) 5 204 12 — 97 318 Total $ 8 $ 286 $ 27 $ — $ 120 $ 441 ____________________ (i) Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program.
Schedule of Restructuring Liability	The changes in the Company’s liability under the Operational Improvement Program from its commencement to December 31, 2017 , are as follows: Termination Benefits Professional Services and Other Total Balance at January 1, 2014 $ — $ — $ — Charges incurred 16 20 36 Cash payments (11 ) (14 ) (25 ) Balance at December 31, 2014 5 6 11 Charges incurred 36 90 126 Cash payments (26 ) (85 ) (111 ) Balance at December 31, 2015 15 11 26 Charges incurred 23 122 145 Cash payments (31 ) (115 ) (146 ) Balance at December 31, 2016 7 18 25 Charges incurred 48 86 134 Cash payments (41 ) (97 ) (138 ) Balance at December 31, 2017 $ 14 $ 7 $ 21 The changes in the Company’s liability under the Business Restructure Program from its commencement to December 31, 2017 , are as follows: Termination Benefits Professional Services and Other Total Balance at January 1, 2016 $ — $ — $ — Charges incurred 45 3 48 Cash payments (19 ) (3 ) (22 ) Balance at December 31, 2016 $ 26 $ — $ 26 Adjustment to prior charges incurred (2 ) — (2 ) Cash payments (23 ) — (23 ) Balance at December 31, 2017 $ 1 $ — $ 1

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income from continuing operations before income taxes and interest in earnings of associates by location of taxing jurisdiction	An analysis of income/(loss) before income taxes by taxing jurisdiction is shown below: Years ended December 31, 2017 2016 2015 Ireland $ (23 ) $ (27 ) $ (61 ) U.S. (198 ) (311 ) (67 ) U.K. 31 123 65 Other jurisdictions 679 555 403 Total $ 489 $ 340 $ 340
Provision for income taxes by location of the taxing jurisdiction	The components of the income tax provision for/(benefit from) income from operations include: Years ended December 31, 2017 2016 2015 Current tax expense/(benefit): U.S. federal taxes $ 65 $ 35 $ 14 U.S. state and local taxes 7 14 1 U.K. corporation tax 14 28 — Other jurisdictions 99 71 51 Total current tax expense 185 148 66 Deferred tax expense/(benefit): U.S. federal taxes (268 ) (214 ) (113 ) U.S. state and local taxes 6 (5 ) (3 ) U.K. corporation tax (9 ) 10 14 Other jurisdictions (14 ) (35 ) 3 Total deferred tax benefit (285 ) (244 ) (99 ) Total benefit from income taxes $ (100 ) $ (96 ) $ (33 )
Reconciliation between US federal income taxes at the statutory rate and the Company's provision for income taxes on continuing operations	The reported income tax provision for /(benefit from) operations differs from the amounts that would have resulted had the reported income before income taxes been taxed at the U.S. federal statutory rate. The principal reasons for the differences between the amounts provided and those that would have resulted from the application of the U.S. federal statutory tax rate are as follows: Years ended December 31, 2017 2016 2015 INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES $ 489 $ 340 $ 340 U.S. federal statutory income tax rate 35 % 35 % 35 % Income tax expense at U.S. federal tax rate 171 119 119 Adjustments to derive effective tax rate: Non-deductible expenses and dividends 68 15 32 Non-deductible acquisition costs 11 1 9 Disposal of non-deductible goodwill 11 2 3 Gain on re-measurement of equity interests — — (20 ) Impact of change in rate on deferred tax balances — (15 ) (5 ) Effect of foreign exchange and other differences 3 6 (1 ) Non-deductible Venezuelan foreign exchange loss 2 4 11 Changes in valuation allowances 13 (74 ) (104 ) Net tax effect of intra-group items (97 ) (98 ) (30 ) Tax differentials of non-U.S. jurisdictions (69 ) (80 ) (42 ) Tax differentials of U.S. state taxes and local taxes (6 ) 14 (2 ) Impact of U.S. Tax Reform (204 ) — — Other items, net (3 ) 10 (3 ) Benefit from income taxes $ (100 ) $ (96 ) $ (33 )
Significant components of deferred income tax assets and liabilities and their balance sheet classifications	Deferred income tax assets and liabilities included in the consolidated balance sheets at December 31, 2017 and 2016 are comprised of the following: December 31, 2017 2016 Deferred tax assets: Accrued expenses not currently deductible $ 131 $ 286 Net operating losses 145 116 Capital loss carryforwards 28 28 Accrued retirement benefits 339 467 Deferred compensation 69 83 Stock options 24 36 Financial derivative transactions 18 12 Gross deferred tax assets 754 1,028 Less: valuation allowance (162 ) (134 ) Net deferred tax assets $ 592 $ 894 Deferred tax liabilities: Cost of intangible assets, net of related amortization $ 929 $ 1,431 Cost of tangible assets, net of related depreciation 56 73 Prepaid retirement benefits 114 85 Accrued revenue not currently taxable 62 119 Deferred tax liabilities $ 1,161 $ 1,708 Net deferred tax liabilities $ 569 $ 814 During December 2017, the Company re-measured its U.S. deferred tax assets and liabilities as a result of U.S. Tax Reform to the newly enacted federal tax rate, which is 21% . The net deferred income tax assets are included in other non-current assets and the net deferred tax liabilities are included in deferred tax liabilities in our consolidated balance sheets. December 31, 2017 2016 Balance sheet classifications: Other non-current assets $ 46 $ 50 Deferred tax liabilities 615 864 Net deferred tax liability $ 569 $ 814
Summary of Valuation Allowance	An analysis of our valuation allowance is shown below. Years ended December 31, 2017 2016 2015 Balance at beginning of year $ 134 $ 187 $ 280 Additions charged against/(credited to) to costs and expenses 35 — — Additions charged against/(credited to) to other accounts — 21 2 Deductions (7 ) (74 ) (95 ) Balance at end of year $ 162 $ 134 $ 187
Reconciliation of the beginning and ending amounts of unrecognized tax benefits	A reconciliation of the beginning and ending balances of the liability for unrecognized tax benefits is as follows: 2017 2016 2015 Balance at beginning of year $ 56 $ 22 $ 19 Increases related to acquisitions — 33 8 Increases related to tax positions in prior years 2 1 1 Decreases related to tax positions in prior years (5 ) (9 ) (6 ) Decreases related to settlements — (1 ) — Decreases related to lapse in statute of limitations (2 ) (1 ) — Increases related to current year tax positions 9 11 2 Cumulative translation adjustment and other adjustments (1 ) — (2 ) Balance at end of year $ 59 $ 56 $ 22
Summary of Income Tax Examinations	Open Tax Years U.S. — federal 2014 and forward U.S. — various states 2012 and forward U.K. 2010 and forward Ireland 2013 and forward France 2010 and forward Germany 2002 and forward Canada - federal 2010 and forward

Fixed Assets (Tables)

Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The following table reflects changes in the net carrying amount of the components of fixed assets for the year ended December 31, 2017 and 2016: Furniture, Leasehold Land and Total Cost: at January 1, 2016 $ 724 $ 272 $ 95 $ 1,091 Additions 265 44 2 311 Acquisitions 109 95 — 204 Disposals (28 ) (8 ) — (36 ) Foreign exchange (61 ) (21 ) (7 ) (89 ) Cost: at December 31, 2016 1,009 382 90 1,481 Additions 303 91 — 394 Disposals (61 ) (21 ) — (82 ) Foreign exchange 49 16 4 69 Cost: at December 31, 2017 $ 1,300 $ 468 $ 94 $ 1,862 Depreciation: at January 1, 2016 $ (393 ) $ (94 ) $ (41 ) $ (528 ) Depreciation expense (119 ) (55 ) (4 ) (178 ) Disposals 17 5 — 22 Foreign exchange 31 7 4 42 Depreciation: at December 31, 2016 (464 ) (137 ) (41 ) (642 ) Depreciation expense (i) (199 ) (47 ) (6 ) (252 ) Disposals 37 14 — 51 Foreign exchange (26 ) (6 ) (2 ) (34 ) Depreciation: at December 31, 2017 $ (652 ) $ (176 ) $ (49 ) $ (877 ) Net book value: At December 31, 2016 $ 545 $ 245 $ 49 $ 839 At December 31, 2017 $ 648 $ 292 $ 45 $ 985
Capital Leases	Included within land and buildings are the following assets held under capital leases: December 31, 2017 2016 Capital leases $ 31 $ 32 Accumulated depreciation (14 ) (12 ) $ 17 $ 20

Goodwill and Other Intangible38

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Goodwill	The components of goodwill are outlined below for the years ended December 31, 2017 and 2016 : HCB CRB IRR BDA Total Balance at December 31, 2015 Goodwill, gross $ 986 $ 2,212 $ 1,031 $ — $ 4,229 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2015 856 1,850 1,031 — 3,737 Purchase price allocation adjustments 8 5 (7 ) — 6 Goodwill acquired during the period (i) 3,458 — 770 2,557 6,785 Goodwill disposed of during the period — (5 ) — — (5 ) Foreign exchange (40 ) (34 ) (36 ) — (110 ) Balance at December 31, 2016 Goodwill, gross $ 4,412 $ 2,178 $ 1,758 $ 2,557 $ 10,905 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2016 4,282 1,816 1,758 2,557 10,413 Goodwill reassigned in segment realignment (ii) (113 ) 13 100 — — Goodwill acquired during the period — 8 — — 8 Goodwill disposed of during the period (31 ) (5 ) (27 ) — (63 ) Foreign exchange 74 67 20 — 161 Balance at December 31, 2017 Goodwill, gross 4,342 2,261 1,851 2,557 11,011 Accumulated impairment losses (130 ) (362 ) — — (492 ) Goodwill, net - December 31, 2017 $ 4,212 $ 1,899 $ 1,851 $ 2,557 $ 10,519 ____________________ (i) Goodwill acquired consists primarily of goodwill recognized from the Merger. (ii) Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2017. See Note 4 — Segment Information for further information.
Changes in the Net Carrying Amount of the Components of Finite-Lived Intangible Assets	The following table reflects changes in the net carrying amount of the components of finite-lived intangible assets for the year ended December 31, 2017 : Balance at December 31, 2016 Intangible assets acquired Intangible assets disposed Amortization (ii) Foreign Exchange Balance at December 31, 2017 Client relationships $ 2,655 $ 13 $ (44 ) $ (379 ) $ 97 $ 2,342 Management contracts 54 — — (4 ) 6 56 Software (i) 570 36 — (150 ) 17 473 Trademark and trade name 1,006 — (1 ) (44 ) 5 966 Product 33 — — (3 ) 3 33 Favorable agreements 11 1 — (2 ) — 10 Other 3 — — (1 ) — 2 Total amortizable intangible assets $ 4,332 $ 50 $ (45 ) $ (583 ) $ 128 $ 3,882 ____________________ (i) All in-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ( $36 million at the date placed into service due to changes in foreign currency exchange rates) have been placed into service during the year ended December 31, 2017 and have been included as intangible assets acquired in this presentation. (ii) Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income. The following table reflects changes in the net carrying amount of the components of finite-lived intangible assets for the year ended December 31, 2016 : Balance as of December 31, 2015 Purchase price allocation adjustments Intangible assets acquired Intangible assets disposed Amortization (ii) Foreign Exchange Balance as of December 31, 2016 Client relationships $ 920 2 $ 2,222 $ (5 ) $ (395 ) $ (89 ) $ 2,655 Management contracts 62 — — — (4 ) (4 ) 54 Software (i) 77 (13 ) 675 — (142 ) (27 ) 570 Trademark and trade name 50 1 1,003 — (45 ) (3 ) 1,006 Product — — 42 — (3 ) (6 ) 33 Favorable agreements 2 — 11 — (2 ) — 11 Other 4 — — — (2 ) 1 3 Total amortizable intangible assets $ 1,115 (10 ) $ 3,953 $ (5 ) $ (593 ) $ (128 ) $ 4,332 ____________________ (i) In-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ( $36 million at December 31, 2016) had not yet been placed in service and are not included in this presentation. (ii) Amortization associated with favorable agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.
Schedule of Carrying Values of Finite-Lived Intangible Assets and Liabilities	The following table reflects the carrying value of finite-lived intangible assets and liabilities at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Client relationships $ 3,462 $ (1,120 ) $ 3,396 $ (741 ) Management contracts 68 (12 ) 62 (8 ) Software 764 (291 ) 711 (141 ) Trademark and trade name 1,055 (89 ) 1,051 (45 ) Product 39 (6 ) 36 (3 ) Favorable agreements 14 (4 ) 13 (2 ) Other 6 (4 ) 6 (3 ) Total finite-lived assets $ 5,408 $ (1,526 ) $ 5,275 $ (943 ) Unfavorable agreements $ 34 $ (8 ) $ 34 $ (5 ) Total finite-lived intangible liabilities $ 34 $ (8 ) $ 34 $ (5 )
Schedule of Future Amortization Expense and Rent Offset	The table below reflects the future estimated amortization expense for amortizable intangible assets and the rent offset resulting from amortization of the net lease intangible assets and liabilities for the next five years and thereafter: Year ending December 31, Amortization Rent offset 2018 $ 535 $ (4 ) 2019 479 (2 ) 2020 426 (3 ) 2021 348 (2 ) 2022 289 (2 ) Thereafter 1,795 (3 ) Total $ 3,872 $ (16 )

Derivative Financial Instrume39

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]	The effects of the material derivative instruments that are designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2017, 2016 and 2015 are as follows: Gain/(loss) recognized in OCI Location (Loss)/gain reclassified Location of (loss)/gain recognized in income (Loss)/gain recognized 2017 2016 2015 2017 2016 2015 2017 2016 2015 Foreign exchange contracts $ 39 $ (127 ) $ (38 ) Other expense/(income), net $ (53 ) $ (42 ) $ 4 Interest expense $ (1 ) $ (1 ) $ 1
Schedule of Derivative Instruments	Derivative Financial Instruments We are exposed to certain interest rate and foreign currency risks. Where possible, we identify exposures in our business that can be offset internally. Where no natural offset is identified, we may choose to enter into various derivative transactions. These instruments have the effect of reducing our exposure to unfavorable changes in interest and foreign currency rates. The Company’s board of directors reviews and approves policies for managing each of these risks as summarized below. Additional information regarding our derivative financial instruments can be found in Note 2 — Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements , Note 11 — Fair Value Measurements and Note 16 — Accumulated Other Comprehensive Loss . Interest Rate Risk - Investment Income As a result of the Company’s operating activities, the Company holds fiduciary funds. The Company earns interest on these funds, which is included in the Company’s consolidated financial statements in interest and other income. These funds are regulated in terms of access as are the instruments in which they may be invested, most of which are short-term in nature. During 2015, 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. These derivatives, with total notional amounts of $300 million , were designated as hedging instruments at December 31, 2017 and December 31, 2016 and had net fair value liabilities of $1 million and nil , respectively. Foreign Currency Risk Certain non-U.S. subsidiaries receive revenues and incur expenses in currencies other than their functional currency, and as a result, the foreign subsidiary’s functional currency revenues will fluctuate as the currency rates change. Additionally, the forecast Pounds sterling expenses of our London brokerage market operations may exceed their Pounds sterling revenues, and they may also hold a significant net Pounds sterling asset or liability position in the consolidated balance sheet. To reduce such variability, we use foreign exchange contracts to hedge against this currency risk. These derivatives were designated as hedging instruments and at December 31, 2017 and December 31, 2016 had total notional amounts of $937 million and $945 million , respectively, and net fair value liabilities of $21 million and $110 million , respectively. At December 31, 2017 , the Company estimates, based on current interest and exchange rates, there will be $26 million of net derivative losses on forward exchange rates, interest rate swaps, and treasury locks reclassified from accumulated other comprehensive income/(loss) into earnings within the next twelve months as the forecast transactions affect earnings. At December 31, 2017 , our longest outstanding maturity was 2.9 years. The effects of the material derivative instruments that are designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2017, 2016 and 2015 are as follows: Gain/(loss) recognized in OCI Location (Loss)/gain reclassified Location of (loss)/gain recognized in income (Loss)/gain recognized 2017 2016 2015 2017 2016 2015 2017 2016 2015 Foreign exchange contracts $ 39 $ (127 ) $ (38 ) Other expense/(income), net $ (53 ) $ (42 ) $ 4 Interest expense $ (1 ) $ (1 ) $ 1 We also enter into foreign currency transactions, primarily to hedge certain intercompany loans. These derivatives are not generally designated as hedging instruments and at December 31, 2017 and December 31, 2016 , we had notional amounts of $971 million and $630 million , respectively, and had a net fair value asset of $3 million , and a net fair value liability of $8 million , respectively. The effects of derivatives that have not been designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2017 , 2016 and 2015 are as follows: Derivatives not designated as hedging instruments: Location of gain/(loss) recognized in income Gain/(loss) recognized 2017 2016 2015 Foreign exchange contracts Other expense/(income), net $ 11 $ (3 ) $ (3 )

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Debt	Short-term debt and current portion of long-term debt consists of the following: December 31, 2017 2016 6.200% senior notes due 2017 $ — $ 394 Current portion of 7-year term loan facility — 22 Current portion of term loan due 2019 85 85 Short-term borrowing under bank overdraft arrangement — 5 Other debt — 2 $ 85 $ 508 Long-term debt consists of the following: December 31, 2017 2016 Revolving $1.25 billion credit facility $ 884 $ — Revolving $800 million credit facility — 238 7-year term loan facility — 196 Term loan due 2019 84 169 7.000% senior notes due 2019 186 186 5.750% senior notes due 2021 497 496 3.500% senior notes due 2021 447 446 2.125% senior notes due 2022 (i) 644 565 4.625% senior notes due 2023 248 247 3.600% senior notes due 2024 645 — 4.400% senior notes due 2026 544 543 6.125% senior notes due 2043 271 271 $ 4,450 $ 3,357
Schedule of Maturities of Long-term Debt	The following table summarizes the maturity of our debt, interest on senior notes and excludes any reduction for debt issuance costs: 2018 2019 2020 2021 2022 Thereafter Total Senior notes $ — $ 187 $ — $ 950 $ 644 $ 1,725 $ 3,506 Interest on senior notes 147 144 134 107 82 464 1,078 Term loans 85 85 — — — — 170 RCF — — — — 884 — 884 Total $ 232 $ 416 $ 134 $ 1,057 $ 1,610 $ 2,189 $ 5,638
Schedule Of Debt Interest Expense	The following table shows an analysis of the interest expense for the years ended December 31: Years ended December 31, 2017 2016 2015 Senior notes $ 148 $ 139 $ 114 Term loans 8 17 5 RCF 17 10 6 WSI revolving credit facility 1 2 2 Other (i) 14 16 15 Total interest expense $ 188 $ 184 $ 142 ________________________ (i) Other primarily includes debt issuance costs, interest expense on capitalized leases and accretion on deferred and contingent consideration.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 : Balance Sheet Location Fair Value Measurements on a Recurring Basis at December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds / exchange traded funds Prepaid and other current assets and other non-current assets $ 40 $ — $ — $ 40 Derivatives: Derivative financial instruments (i) Prepaid and other current assets and other non-current assets $ — $ 18 $ — $ 18 Liabilities: Contingent consideration: Contingent consideration (ii) Other current liabilities and other non-current liabilities $ — $ — $ 51 $ 51 Derivatives: Derivative financial instruments (i) Other current liabilities and other non-current liabilities $ — $ 37 $ — $ 37 Balance Sheet Location Fair Value Measurements on a Recurring Basis at December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Available-for-sale securities: Mutual funds / exchange traded funds Prepaid and other current assets and other non-current assets $ 37 $ — $ — $ 37 Derivatives: Derivative financial instruments (i) Prepaid and other current assets and other non-current assets $ — $ 15 $ — $ 15 Liabilities: Contingent consideration: Contingent consideration (ii) Other current liabilities and other non-current liabilities $ — $ — $ 55 $ 55 Derivatives: Derivative financial instruments (i) Other current liabilities and other non-current liabilities $ — $ 133 $ — $ 133 ____________________ (i) See Note 9 — Derivative Financial Instruments for further information on our derivative instruments. (ii) Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The weighted-average discount rate used on our material contingent consideration calculations was 9.64% and 10.76% at December 31, 2017 and December 31, 2016, respectively. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table summarizes the change in fair value of the Level 3 liabilities: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) December 31, 2017 Balance at December 31, 2016 $ 55 Obligations assumed — Net sales (7 ) Payments (10 ) Realized and unrealized gains 9 Foreign exchange 4 Balance at December 31, 2017 $ 51
Schedule of Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis	The following tables present our liabilities not measured at fair value on a recurring basis at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Short-term debt and current portion of long-term debt $ 85 $ 85 $ 508 $ 513 Long-term debt $ 4,450 $ 4,706 $ 3,357 $ 3,504

Retirement Benefits (Tables)

Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Changes in Projected Benefit Obligations	The following schedules provide information concerning the defined benefit pension plans and PRW plan as of and for the years ended December 31, 2017 and 2016 : 2017 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Change in Benefit Obligation Benefit obligation, beginning of year $ 4,169 $ 3,899 $ 732 $ 113 $ 976 $ 2,881 $ 184 $ — Service cost 66 32 20 — 59 24 19 1 Interest cost 139 93 17 4 137 114 18 3 Employee contributions 6 1 — 6 — 1 — 7 Actuarial losses 293 2 5 14 151 852 61 4 Settlements (16 ) (138 ) (1 ) — — (12 ) (61 ) — Benefits paid (181 ) (93 ) (29 ) (14 ) (166 ) (130 ) (24 ) (14 ) Business combinations — — — — 3,012 842 530 112 Transfers in — — 1 — — — 1 — Foreign currency changes — 369 77 — — (673 ) 4 — Benefit obligation, end of year $ 4,476 $ 4,165 $ 822 $ 123 $ 4,169 $ 3,899 $ 732 $ 113 Change in Plan Assets Fair value of plan assets, beginning of year $ 3,280 $ 4,360 $ 467 $ 4 $ 749 $ 3,478 $ 158 $ — Actual return on plan assets 464 290 42 — 153 782 26 — Employer contributions 101 66 34 6 91 106 39 7 Employee contributions 6 1 — 6 — 1 — 7 Settlements (16 ) (138 ) (1 ) — — (12 ) (58 ) — Benefits paid (181 ) (93 ) (29 ) (14 ) (166 ) (130 ) (24 ) (14 ) Business combinations — — — — 2,453 906 321 4 Transfers in — — 1 — — — 1 — Foreign currency adjustment — 424 48 — — (771 ) 4 — Fair value of plan assets, end of year $ 3,654 $ 4,910 $ 562 $ 2 $ 3,280 $ 4,360 $ 467 $ 4 Funded status at end of year $ (822 ) $ 745 $ (260 ) $ (121 ) $ (889 ) $ 461 $ (265 ) $ (109 ) Accumulated Benefit Obligation $ 4,476 $ 4,165 $ 790 $ 123 $ 4,169 $ 3,899 $ 696 $ 113 Components on the Consolidated Balance Sheet Pension benefits assets $ — $ 754 $ 17 $ — $ — $ 478 $ 10 $ — Current liability for pension benefits $ (40 ) $ — $ (6 ) $ (5 ) $ (47 ) $ — $ (7 ) $ (3 ) Non-current liability for pension benefits $ (782 ) $ (9 ) $ (271 ) $ (116 ) $ (842 ) $ (17 ) $ (268 ) $ (106 ) $ (822 ) $ 745 $ (260 ) $ (121 ) $ (889 ) $ 461 $ (265 ) $ (109 )
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	Amounts recognized in accumulated other comprehensive loss as of December 31, 2017 and 2016 consist of: 2017 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Net actuarial loss $ 663 $ 909 $ 79 $ 19 $ 603 $ 918 $ 80 $ 4 Net prior service gain — (142 ) — — — (147 ) — — Accumulated other comprehensive loss $ 663 $ 767 $ 79 $ 19 $ 603 $ 771 $ 80 $ 4
Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets	The following table presents the projected benefit obligation and fair value of plan assets for our plans that have a projected benefit obligation in excess of plan assets as of December 31, 2017 and 2016 : 2017 2016 U.S. U.K. Other U.S. U.K. Other Projected benefit obligation at end of year $ 4,476 $ 10 $ 758 $ 4,169 $ 843 $ 686 Fair value of plan assets at end of year $ 3,654 $ — $ 481 $ 3,280 $ 825 $ 411
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	The following table presents the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for our plans that have an accumulated benefit obligation in excess of plan assets as of December 31, 2017 and 2016 . 2017 2016 U.S. U.K. Other U.S. U.K. Other Projected benefit obligation at end of year $ 4,476 $ 10 $ 758 $ 4,169 $ 843 $ 686 Accumulated benefit obligation at end of year $ 4,476 $ 10 $ 726 $ 4,169 $ 843 $ 650 Fair value of plan assets at end of year $ 3,654 $ — $ 481 $ 3,280 $ 825 $ 411
Schedule of Net Periodic Benefit Cost	The components of the net periodic benefit income and other amounts recognized in other comprehensive (income)/loss for the years ended December 31, 2017, 2016 and 2015 for the defined benefit pension and PRW plans are as follows: 2017 2016 2015 U.S. U.K. Other PRW U.S. U.K. Other PRW U.S. U.K. Other PRW Components of net periodic benefit (income)/cost: Service cost $ 66 $ 32 $ 20 $ — $ 59 $ 24 $ 19 $ 1 $ — $ 33 $ 3 $ — Interest cost 139 93 17 4 137 114 18 3 41 107 3 — Expected return on plan assets (245 ) (284 ) (30 ) — (240 ) (253 ) (27 ) — (57 ) (230 ) (3 ) — Amortization of unrecognized prior service credit — (18 ) — — — (19 ) — — — (18 ) — — Amortization of unrecognized actuarial loss 13 53 2 — 12 42 — — 11 36 1 — Settlement 1 37 1 — — — 5 — — — — — Curtailment gain — — — — — — — — — (5 ) — — Net periodic benefit (income)/cost $ (26 ) $ (87 ) $ 10 $ 4 $ (32 ) $ (92 ) $ 15 $ 4 $ (5 ) $ (77 ) $ 4 $ — Other changes in plan assets and benefit obligations recognized in other comprehensive loss/(income): Net actuarial loss/(gain) $ 74 $ (4 ) $ (7 ) $ 14 $ 238 $ 323 $ 62 $ 4 $ (16 ) $ 59 $ (5 ) $ — Amortization of unrecognized actuarial loss (13 ) (53 ) (2 ) — (12 ) (42 ) — — (11 ) (36 ) (1 ) — Prior service gain — — — — — — — — — (215 ) — — Amortization of unrecognized prior service credit — 18 — — — 19 — — — 18 — — Settlement (1 ) (37 ) (1 ) — — — (8 ) — — — — — Curtailment loss — — — — — — — — — 18 — — Total recognized in other comprehensive loss/(income) 60 (76 ) (10 ) 14 226 300 54 4 (27 ) (156 ) (6 ) — Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income) $ 34 $ (163 ) $ — $ 18 $ 194 $ 208 $ 69 $ 8 $ (32 ) $ (233 ) $ (2 ) $ —
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	The estimated net actuarial loss and prior service gain for the defined benefit plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year are: For the Year Ended December 31, 2018 U.S. U.K Other PRW Estimated net actuarial loss $ 11 $ 47 $ 2 $ 1 Prior service gain $ — $ (19 ) $ — $ —
Schedule of Assumptions Used	The assumptions used to determine net periodic benefit cost for the fiscal years ended December 31, 2017, 2016, and 2015 were as follows: Years ended December 31, 2017 2016 2015 U.S. U.K. Other PRW U.S. U.K. Other PRW U.S. U.K. Other PRW Discount rate (i) N/A N/A N/A N/A N/A N/A N/A N/A 3.9 % 3.6 % 2.3 % — % Discount rate - PBO 4.0 % 2.6 % 2.7 % 4.0 % 4.2 % 3.8 % 3.2 % 4.2 % N/A N/A N/A — % Discount rate - service cost 3.9 % 2.6 % 3.0 % 3.9 % 3.9 % 3.8 % 3.4 % 4.1 % N/A N/A N/A — % Discount rate - interest cost on service cost 3.2 % 2.4 % 2.8 % 3.5 % 3.2 % 3.8 % 3.1 % 3.5 % N/A N/A N/A — % Discount rate - interest cost on PBO 3.4 % 2.3 % 2.3 % 3.3 % 3.4 % 3.4 % 2.8 % 3.3 % N/A N/A N/A — % Expected long-term rate of return on assets 7.6 % 6.3 % 6.1 % 2.0 % 7.6 % 6.2 % 6.1 % 2.0 % 7.3 % 6.5 % 3.3 % — % Rate of increase in compensation levels 4.3 % 3.2 % 2.3 % N/A 4.3 % 3.2 % 2.3 % N/A N/A 2.9 % 2.2 % — % Healthcare cost trend Initial rate 7.0 % 7.0 % N/A Ultimate rate 5.0 % 5.0 % N/A Year reaching ultimate rate 2022 2022 N/A ____________________ (i) This discount rate represents the assumption to determine net periodic benefit cost prior to the Company’s use of the granular approach to calculating service and interest cost which began for the 2016 fiscal year. The following tables present the assumptions used in the valuation to determine the projected benefit obligation for the fiscal years ended December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 U.S. U.K. Other PRW U.S. U.K. Other PRW Discount rate 3.6 % 2.6 % 2.6 % 3.5 % 4.0 % 2.6 % 2.7 % 4.0 % Rate of increase in compensation levels 4.3 % 3.0 % 2.3 % N/A 4.3 % 3.2 % 2.3 % N/A
Schedule of Allocation of Plan Assets	The Company’s pension plan asset target allocations as of December 31, 2017 were as follows: U.S. U.K. Canada Germany Ireland Asset Category Willis Towers Watson Willis Towers Watson Miller Towers Watson Towers Watson Willis Towers Watson Equity securities 35 % 23 % 33 % 11 % 33 % 60 % 30 % 32 % 71 % Debt securities 54 % 43 % 47 % 56 % 55 % 40 % 51 % 27 % 29 % Real estate 11 % 6 % 2 % — % — % — % — % 3 % — % Other — % 28 % 18 % 33 % 12 % — % 19 % 38 % — % Total 100 % 100 % 100 % 100 % 100 % 100 % 100 % 100 % 100 % The fair values of our U.S. plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 10 $ — $ — $ 10 $ 3 $ — $ — $ 3 Short-term securities — 283 — 283 — 33 — 33 Equity securities 202 — — 202 253 8 — 260 Government bonds 10 — — 10 10 — — 10 Corporate bonds — 193 — 193 — 169 — 170 Other fixed income — 20 — 20 — 19 — 19 Pooled / commingled funds — — — 1,922 — — — 1,665 Mutual funds 1 — — 1 183 — — 183 Private equity — — — 287 — — — 234 Hedge funds — — — 724 — — — 692 Total assets $ 223 $ 496 $ — $ 3,652 $ 449 $ 229 $ — $ 3,269 The fair values of our U.K. plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 92 $ — $ — $ 92 $ 49 $ — $ — $ 49 Equity securities 24 — — 24 374 8 — 382 Government bonds 1,841 — — 1,841 1,184 — — 1,184 Corporate bonds — 224 — 224 — 118 — 118 Other fixed income — 246 — 246 — 216 — 216 Pooled / commingled funds — — — 2,294 — — — 1,677 Mutual funds — — — 8 — — — 11 Private equity — — — 32 — — — 40 Derivatives — 102 — 102 — 73 — 73 Real estate — — — 218 — — — 197 Hedge funds — — — 393 — — — 426 Total assets $ 1,957 $ 572 $ — $ 5,474 $ 1,607 $ 415 $ — $ 4,373 Liability category: Repurchase agreements — 549 — 549 — — — — Derivatives — 16 — 16 — 14 — 14 Net assets $ 1,957 $ 7 $ — $ 4,909 $ 1,607 $ 401 $ — $ 4,359 The fair values of our Other plan assets by asset category at December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Asset category: Cash $ 5 $ — $ — $ 5 $ 17 $ — $ — $ 17 Pooled / commingled funds — — — 327 — — — 214 Mutual funds — — — 209 — — — 224 Insurance contracts — — 19 19 — — 17 17 Total assets $ 5 $ — $ 19 $ 560 $ 17 $ — $ 17 $ 472
Schedule of Net Plan Investments Reconciliation To Total Fair Value Of Plan Assets	The following table reconciles the net plan investments to the total fair value of the plan assets: December 31, 2017 2016 Net assets held in investments $ 9,121 $ 8,100 PRW plan assets 2 3 Net receivable for investments purchased 2 3 Dividend and interest receivable 3 3 Fair value of plan assets $ 9,128 $ 8,109
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	The following table sets forth a summary of changes in the fair value of the plans’ Level 3 assets for the fiscal year ended December 31, 2017 : Level 3 Roll Forward Beginning balance at December 31, 2016 $ 17 Foreign exchange 2 Ending balance at December 31, 2017 $ 19
Schedule of Accumulated and Projected Benefit Obligations	The following table sets forth our projected pension contributions to our qualified plans for fiscal year 2018, as well as the pension contributions to our qualified plans in fiscal years 2017 and 2016: 2018 2017 2016 U.S. $ 50 $ 50 $ 50 U.K. $ 81 $ 65 $ 105 Other $ 13 $ 13 $ 29
Schedule of Expected Benefit Payments	Expected benefit payments from our defined benefit pension plans to current plan participants, including the effect of their expected future service, as appropriate, are as follows: Benefit Payments Fiscal Year U.S. U.K. Other PRW Total 2018 230 112 36 16 394 2019 236 111 26 17 390 2020 245 117 27 18 407 2021 249 127 29 19 424 2022 260 129 36 20 445 Years 2023 – 2027 1,386 764 179 117 2,446 $ 2,606 $ 1,360 $ 333 $ 207 $ 4,506

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Future minimum rental commitments under all non-cancellable operating lease agreements	As of December 31, 2017 , the aggregate future minimum rental commitments under all non-cancellable operating lease agreements are as follows: Gross rental Rentals from Net rental 2018 $ 204 $ (16 ) $ 188 2019 191 (13 ) 178 2020 165 (13 ) 152 2021 138 (10 ) 128 2022 120 (4 ) 116 Thereafter 585 (5 ) 580 Total $ 1,403 $ (61 ) $ 1,342

Supplementary Information for44

Supplementary Information for Certain Balance Sheet Accounts (Tables)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Accounts Receivable, Net	Accounts receivable, net consists of the following: December 31, December 31, Billed, net of allowance for doubtful debts of $45 million and $40 million $ 1,933 $ 1,789 Accrued and unbilled, at estimated net realizable value 313 291 Accounts receivable, net $ 2,246 $ 2,080
Schedule of Credit Losses for Financing Receivables, Current	Accounts receivable are stated at estimated net realizable values. The provisions, shown below as of the end of each period, are recorded as the amounts considered by management to be sufficient to meet probable future losses related to uncollectible accounts. December 31, December 31, December 31, Balance at beginning of year $ 40 $ 22 $ 12 Additions charged to costs and expenses 17 36 5 Charges to other accounts - acquisitions — 8 11 Deductions/other movements (9 ) (27 ) (7 ) Foreign exchange (3 ) 1 1 Balance at end of year $ 45 $ 40 $ 22
Schedule of Prepaid and Other Current Assets	Prepaid and other current assets consist of the following: December 31, December 31, Prepayments and accrued income $ 132 $ 131 Derivatives and investments 29 32 Deferred compensation plan assets 21 15 Retention incentives 7 7 Corporate income and other taxes 170 97 Other current assets 71 55 Total prepaid and other current assets $ 430 $ 337
Schedule of Other Non-current Assets	Other non-current assets consist of the following: December 31, December 31, Prepayments and accrued income $ 18 $ 15 Deferred compensation plan assets 135 111 Deferred tax assets 46 50 Accounts receivable, net 33 27 Other investments 26 30 Other non-current assets 189 120 Total other non-current assets $ 447 $ 353
Schedule of Other Current Liabilities	Other current liabilities consist of the following: December 31, December 31, Accounts payable $ 136 $ 117 Income and other taxes payable 90 91 Contingent and deferred consideration on acquisition 55 53 Payroll-related liabilities 209 200 Derivatives 32 80 Third party commissions 172 184 Other current liabilities 110 151 Total other current liabilities $ 804 $ 876
Analysis of Movements on Provisions for Liabilities	Provision for liabilities consists of the following: December 31, December 31, Claims, lawsuits and other proceedings $ 474 $ 508 Other provisions 84 67 Total provision for liabilities $ 558 $ 575
Schedule of Other Non-Current Liabilities	Other non-current liabilities consist of the following: December 31, December 31, Incentives from lessors $ 138 $ 133 Deferred compensation plan liability 135 111 Contingent and deferred consideration on acquisitions 41 89 Derivatives 5 51 Other non-current liabilities 225 148 Total other non-current liabilities $ 544 $ 532

Other Expense_(Income), Net (Ta

Other Expense/(Income), Net (Tables)	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Expense/(Income)	Other expense/(income), net consists of the following: Years ended December 31, 2017 2016 2015 Gain on disposal of operations $ (13 ) $ (2 ) $ (25 ) Gain on re-measurement of equity interests (i) — — (59 ) Impact of Venezuelan currency devaluation (ii) 2 — 30 Foreign exchange loss/(gain) 72 29 (1 ) Other expense/(income), net $ 61 $ 27 $ (55 ) ____________________ (i) Prior to the acquisition date, the Company accounted for its 30% interest in Gras Savoye as an equity-method investment. The acquisition-date fair value of the previously held equity interest was $158 million and is included in the measurement of the consideration transferred. The Company recognized a gain of $59 million as a result of remeasuring its prior equity interest in Gras Savoye held before the business combination. (ii) On December 31, 2015 the Company began using the SIMADI rate for the Venezuelan bolivar (approximately Venezuelan bolivars 198.7 = U.S. dollar 1) instead of the SICAD I auction rate (approximately Venezuelan bolivars 13.5 = U.S. dollar 1) to translate on Venezuelan retail operations. In March 2016, the DICOM mechanism replaced the SIMADI mechanism. At December 31, 2017, the DICOM rate was approximately Venezuelan bolivars 3,345 = U.S. dollar 1. The Company does not expect the additional devaluation which occurred in January 2018 to be material.

Accumulated Other Comprehensi46

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive Income (Loss)	The components of other comprehensive income/(loss) are as follows: December 31, 2017 December 31, 2016 December 31, 2015 Before tax amount Tax Net of tax amount Before tax amount Tax Net of tax amount Before tax amount Tax Net of tax amount Other comprehensive income/(loss): Foreign currency translation $ 295 $ — $ 295 $ (353 ) $ — $ (353 ) $ (133 ) $ — $ (133 ) Defined pension and post-retirement benefits 3 11 14 (553 ) 114 (439 ) 233 (53 ) 180 Derivative instruments 90 (15 ) 75 (87 ) 12 (75 ) (35 ) 7 (28 ) Other comprehensive income/(loss) 388 (4 ) 384 (993 ) 126 (867 ) 65 (46 ) 19 Less: Other comprehensive (income)/loss attributable to non-controlling interests (13 ) — (13 ) 20 — 20 10 — 10 Other comprehensive income/(loss) attributable to Willis Towers Watson $ 375 $ (4 ) $ 371 $ (973 ) $ 126 $ (847 ) $ 75 $ (46 ) $ 29
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in the components of accumulated other comprehensive loss, net of tax, are included in the following table. This table excludes amounts attributable to non-controlling interests, which are not material for further disclosure. Foreign currency translation (i) Cash flow hedges (i) Defined pension and post-retirement benefit costs (ii) Total Balance, January 1, 2015 $ (191 ) $ 18 $ (893 ) $ (1,066 ) Other comprehensive (loss)/income before reclassifications (123 ) (31 ) 158 4 Loss reclassified from accumulated other comprehensive loss (net of income tax expense of $8) — 3 22 25 Net other comprehensive (loss)/income (123 ) (28 ) 180 29 Balance, December 31, 2015 $ (314 ) $ (10 ) $ (713 ) $ (1,037 ) Other comprehensive loss before reclassifications (336 ) (110 ) (483 ) (929 ) Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $5) — 38 44 82 Net other comprehensive loss (336 ) (72 ) (439 ) (847 ) Balance, December 31, 2016 $ (650 ) $ (82 ) $ (1,152 ) $ (1,884 ) Other comprehensive income/(loss) before reclassifications 285 28 (26 ) 287 Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $18) — 44 40 84 Net other comprehensive income 285 72 14 371 Balance, December 31, 2017 $ (365 ) $ (10 ) $ (1,138 ) $ (1,513 ) ____________________ (i) Reclassification adjustments from accumulated other comprehensive income are included in Other expense/(income), net in the accompanying consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the hedge settlements. (ii) Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 12 — Retirement Benefits ) which is included in Salaries and benefits in the accompanying consolidated statements of comprehensive income .

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Assumptions Used on Options	The fair value of each option is estimated on the date of grant using the Black-Scholes option pricing model that uses the assumptions noted in the following table. Expected volatility is based on historical volatility of the Company’s shares. The Company uses the simplified method set out in ASC 718 – Compensation – Stock Compensation to derive the expected term of options granted as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The risk-free rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year. Years ended December 31, 2017 2016 2015 Expected volatility 19.8 % 21.0 % 17.4 % Expected dividends 1.4 % 1.5 % 2.7 % Expected life (years) 4.2 2.7 4.0 Risk-free interest rate 1.6 % 0.7 % 1.5 % The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year. There were no performance-based RSUs granted during the year ended December 31, 2015. Years ended December 31, 2017 2016 Expected volatility 20.2 % 20.3 % Expected dividend yield — % — % Expected life (years) 2.4 2.6 Risk-free interest rate 1.4 % 0.8 %
Schedule of Share-based Compensation, Stock Options, Activity	A summary of option activity under the plans at December 31, 2017 , and changes during the year then ended is presented below: Options Weighted- Weighted- Aggregate (thousands) Price (i) Term Value Time-based stock options Balance as of December 31, 2016 1,201 $ 102.38 Granted 38 $ 143.60 Exercised (448 ) $ 100.61 Forfeited (37 ) $ 103.22 Balance as of December 31, 2017 754 $ 105.47 4 years $ 34 Options vested or expected to vest at December 31, 2017 751 $ 105.17 4 years $ 34 Options exercisable at December 31, 2017 581 $ 101.43 4 years $ 29 Performance-based stock options Balance as of December 31, 2016 883 $ 101.95 Exercised (182 ) $ 87.49 Forfeited (21 ) $ 82.90 Balance as of December 31, 2017 680 $ 106.42 4 years $ 30 Options vested or expected to vest at December 31, 2017 680 $ 106.42 4 years $ 30 Options exercisable at December 31, 2017 190 $ 95.36 1 year $ 11 ____________________ (i) Certain options are exercisable in Pounds sterling and are converted to dollars using the exchange rate at December 31, 2017.
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	A summary of time-based and performance-based RSU activity under the plans at December 31, 2017 , and changes during the year then ended, is presented below: Shares Weighted- (thousands) Fair Value Nonvested shares (time-based RSUs) Balance, beginning of year 437 $ 118.98 Granted 17 $ 153.40 Vested (179 ) $ 119.50 Forfeited (132 ) $ 119.09 Balance, end of year 143 $ 122.27 Nonvested shares (performance-based RSUs) Balance, beginning of year 1,200 $ 121.78 Granted 140 $ 148.18 Vested (319 ) $ 119.63 Forfeited (140 ) $ 121.30 Balance, end of year 881 $ 90.61

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	Basic and diluted earnings per share are as follows: Years ended December 31, 2017 2016 2015 (i) Net income attributable to Willis Towers Watson $ 568 $ 420 $ 373 Basic weighted-average number of shares outstanding 135 137 68 Dilutive effect of potentially issuable shares 1 1 1 Diluted weighted-average number of shares outstanding 136 138 69 Basic earnings per share $ 4.21 $ 3.07 $ 5.49 Dilutive effect of potentially issuable shares (0.03 ) (0.03 ) (0.08 ) Diluted earnings per share $ 4.18 $ 3.04 $ 5.41 ____________________ (i) Shares outstanding, potentially issuable shares, basic and diluted earnings per share, and the dilutive effect of potentially issuable shares, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split effected on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.

Supplemental Disclosures of C49

Supplemental Disclosures of Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Supplemental disclosures regarding cash flow information and non-cash flow investing and financing activities	Supplemental disclosures regarding cash flow information and non-cash investing and financing activities are as follows: Years Ended December 31, 2017 2016 2015 Supplemental disclosures of cash flow information: Cash payments for income taxes, net $ 203 $ 158 $ 91 Cash payments for interest $ 169 $ 143 $ 126 Cash acquired $ — $ 476 $ 148 Supplemental disclosures of non-cash investing and financing activities: Issuance of shares and assumed awards in connection with the Merger $ — $ 8,723 $ — Fair value of deferred and contingent consideration related to acquisitions $ — $ — $ 204

Quarterly Financial Data (Una50

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly financial data	Quarterly financial data for 2017 and 2016 were as follows: Three Months Ended March 31, June 30, September 30, December 31, 2017 Total revenues $ 2,319 $ 1,953 $ 1,852 $ 2,078 Total costs of providing services $ 1,856 $ 1,829 $ 1,811 $ 1,968 Income/(loss) from operations $ 463 $ 124 $ 41 $ 110 Net income/(loss) $ 352 $ 41 $ (54 ) $ 253 Net income/(loss) attributable to Willis Towers Watson $ 344 $ 33 $ (54 ) $ 245 Earnings/(loss) per share — Basic $ 2.51 $ 0.24 $ (0.40 ) $ 1.85 — Diluted $ 2.50 $ 0.24 $ (0.40 ) $ 1.84 2016 Total revenues $ 2,234 $ 1,949 $ 1,777 $ 1,927 Total costs of providing services $ 1,908 $ 1,813 $ 1,776 $ 1,839 Income from operations $ 326 $ 136 $ 1 $ 88 Net income/(loss) $ 245 $ 76 $ (31 ) $ 148 Net income/(loss) attributable to Willis Towers Watson $ 238 $ 72 $ (32 ) $ 142 Earnings/(loss) per share — Basic $ 1.76 $ 0.52 $ (0.23 ) $ 1.04 — Diluted $ 1.75 $ 0.51 $ (0.23 ) $ 1.03

Financial Information for Par51

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Unaudited Condensed Consolidated Statement of Comprehensive Income	Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — 19 — 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 — 4,693 — 4,745 Other operating expenses 3 111 1 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 23 — 109 — 132 Transaction and integration expenses — 92 — 177 — 269 Total costs of providing services 7 283 1 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (264 ) (1 ) 1,007 3 738 Income from Group undertakings — (614 ) (149 ) (148 ) 911 — Expenses due to Group undertakings — 230 26 655 (911 ) — Interest expense 30 34 103 21 — 188 Other (income)/expense, net (35 ) (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 86 19 621 (235 ) 489 (Benefit from)/provision for income taxes — (24 ) 2 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 110 17 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 483 290 — (1,343 ) — NET INCOME 568 593 307 702 (1,578 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 307 $ 678 $ (1,578 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 663 $ 1,050 $ (2,629 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 663 $ 1,013 $ (2,629 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 21 — 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 — 4,628 — 4,646 Other operating expenses 3 200 — 1,348 — 1,551 Depreciation — 19 — 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 68 — 125 — 193 Transaction and integration expenses 1 42 — 134 — 177 Total costs of providing services 6 345 — 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) — 881 — 551 Income from Group undertakings (3 ) (657 ) (132 ) (136 ) 928 — Expenses due to Group undertakings 3 228 26 671 (928 ) — Interest expense 32 38 90 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 69 16 293 — 340 (Benefit from)/provision for income taxes — (125 ) 3 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 194 13 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 254 151 — (863 ) — NET INCOME 420 448 164 269 (863 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 164 $ 251 $ (863 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (379 ) $ (656 ) $ (550 ) $ 1,583 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (379 ) $ (656 ) $ (548 ) $ 1,583 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ — $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 12 — 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 — 2,225 — 2,303 Other operating expenses 8 101 — 609 — 718 Depreciation — 22 — 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 41 — 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 255 — 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) — 683 — 427 Income from Group undertakings — (374 ) (93 ) (110 ) 577 — Expenses due to Group undertakings — 200 26 351 (577 ) — Interest expense 43 41 40 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (68 ) 27 447 — 340 (Benefit from)/provision for income taxes — (51 ) 5 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) (17 ) 22 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 443 337 — (1,219 ) — NET INCOME 373 435 359 436 (1,219 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 359 $ 425 $ (1,219 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 400 $ 455 $ (1,316 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 400 $ 454 $ (1,316 ) $ 402
Unaudited Condensed Consolidated Balance Sheet	Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — 4 — 2,242 — 2,246 Prepaid and other current assets — 314 1 264 (149 ) 430 Amounts due from group undertakings 6,202 1,420 2,807 3,626 (14,055 ) — Total current assets 6,204 1,739 2,808 19,314 (14,204 ) 15,861 Investments in subsidiaries 4,506 10,052 1,918 — (16,476 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 146 3 388 (90 ) 447 Non-current amounts due from group undertakings — 4,884 1,775 — (6,659 ) — Total non-current assets 4,506 15,167 3,696 16,513 (23,285 ) 16,597 TOTAL ASSETS $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 — 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 112 33 724 (152 ) 804 Amounts due to group undertakings — 10,467 1,658 1,930 (14,055 ) — Total current liabilities 87 10,605 1,691 16,579 (14,207 ) 14,755 Long-term debt 497 986 2,883 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — 120 — 438 — 558 Other non-current liabilities — 24 — 520 — 544 Non-current amounts due to group undertakings — 519 423 5,717 (6,659 ) — Total non-current liabilities 497 1,649 3,306 8,722 (6,748 ) 7,426 TOTAL LIABILITIES 584 12,254 4,997 25,301 (20,955 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 1,507 10,375 (16,534 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 1,507 10,498 (16,534 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — 7 — 2,073 — 2,080 Prepaid and other current assets — 74 1 324 (62 ) 337 Amounts due from group undertakings 7,229 849 1,595 2,370 (12,043 ) — Total current assets 7,229 930 1,596 16,142 (12,105 ) 13,792 Investments in subsidiaries 3,409 8,621 7,309 — (19,339 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 90 — 310 (47 ) 353 Non-current amounts due from group undertakings — 4,859 1,055 — (5,914 ) — Total non-current assets 3,409 13,668 8,364 16,384 (25,364 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 41 1 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 394 22 92 — 508 Other current liabilities 77 87 33 684 (5 ) 876 Amounts due to group undertakings — 9,946 — 2,097 (12,043 ) — Total current liabilities 77 10,468 56 14,866 (12,097 ) 13,370 Long-term debt 496 186 2,506 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — 120 — 455 — 575 Other non-current liabilities — 63 — 483 (14 ) 532 Non-current amounts due to group undertakings — 518 423 4,973 (5,914 ) — Total non-current liabilities 496 887 2,929 8,414 (6,077 ) 6,649 TOTAL LIABILITIES 573 11,355 2,985 23,280 (18,174 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 6,975 9,077 (19,295 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 6,975 9,195 (19,295 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253
Unaudited Condensed Consolidated Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (8,634 ) — Repayments of intercompany financing activities — (30 ) (118 ) 148 — Net cash (used in)/from financing activities $ (832 ) $ 5,056 $ 3,397 $ (8,396 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 626 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — (857 ) — (857 ) Net disposals of operations — — 44 — 44 Other, net — — 16 — 16 Proceeds from intercompany investing activities 321 136 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (1,226 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — 469 Proceeds from issue of other debt — 592 — — 592 Debt issuance costs — (5 ) — — (5 ) Repayments of debt — (165 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — (82 ) Proceeds from issuance of shares 124 — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — (1 ) — (1 ) Dividends paid (277 ) — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 600 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (640 ) $ 29 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 275 1,076 1,237 (3,630 ) — Repayments of intercompany investing activities — (73 ) (2,676 ) (1,722 ) 4,471 — Reduction in investment in subsidiaries 104 1,288 — 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (570 ) (148 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 912 $ (1,748 ) $ (347 ) $ 841 $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 155 487 — — 642 Senior notes issued — 649 — — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (5 ) (4 ) — — (9 ) Repayments of debt — (394 ) (220 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) (58 ) — (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,920 1,482 1,069 (4,471 ) — Repayments of intercompany financing activities — (2,538 ) (26 ) (1,066 ) 3,630 — Net cash (used in)/from financing activities $ (748 ) $ (271 ) $ 1,719 $ (547 ) $ (632 ) $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 308 $ 152 $ 1,114 $ (621 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) — (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — 33 — 20 (30 ) 23 Proceeds from intercompany investing activities — 108 55 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (3,513 ) (602 ) (769 ) 8,635 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (4,463 ) $ (547 ) $ (4,153 ) $ 8,509 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — — (237 ) — — (237 ) Senior notes issued — — 1,606 — — 1,606 Proceeds from issuance of other debt — — 400 4 — 404 Debt issuance costs — — (14 ) — — (14 ) Repayments of debt (300 ) — (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) (162 ) (302 ) (90 ) 554 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 1 4,266 (8,635 ) — Repayments of intercompany financing activities — (53 ) (22 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,153 $ 395 $ 3,397 $ (7,888 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 593 $ 33 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) — (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 136 — 151 (608 ) — Repayments of intercompany investing activities (82 ) — (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (420 ) (178 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (302 ) $ (924 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings of revolving credit facility — — 469 — — 469 Proceeds from issue of other debt — — 592 — — 592 Debt issuance costs — — (5 ) — — (5 ) Repayments of debt — (149 ) (16 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares and excess tax benefit 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 — 828 (1,009 ) — Repayments of intercompany financing activities — (323 ) (149 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ (291 ) $ 891 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532

Financial Information for Par52

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Unaudited Condensed Consolidated Statement of Comprehensive Income	Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — 19 — 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 — 4,693 — 4,745 Other operating expenses 3 111 1 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 23 — 109 — 132 Transaction and integration expenses — 92 — 177 — 269 Total costs of providing services 7 283 1 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (264 ) (1 ) 1,007 3 738 Income from Group undertakings — (614 ) (149 ) (148 ) 911 — Expenses due to Group undertakings — 230 26 655 (911 ) — Interest expense 30 34 103 21 — 188 Other (income)/expense, net (35 ) (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 86 19 621 (235 ) 489 (Benefit from)/provision for income taxes — (24 ) 2 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 110 17 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 483 290 — (1,343 ) — NET INCOME 568 593 307 702 (1,578 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 307 $ 678 $ (1,578 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 663 $ 1,050 $ (2,629 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 663 $ 1,013 $ (2,629 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 21 — 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 — 4,628 — 4,646 Other operating expenses 3 200 — 1,348 — 1,551 Depreciation — 19 — 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 68 — 125 — 193 Transaction and integration expenses 1 42 — 134 — 177 Total costs of providing services 6 345 — 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) — 881 — 551 Income from Group undertakings (3 ) (657 ) (132 ) (136 ) 928 — Expenses due to Group undertakings 3 228 26 671 (928 ) — Interest expense 32 38 90 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 69 16 293 — 340 (Benefit from)/provision for income taxes — (125 ) 3 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 194 13 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 254 151 — (863 ) — NET INCOME 420 448 164 269 (863 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 164 $ 251 $ (863 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (379 ) $ (656 ) $ (550 ) $ 1,583 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (379 ) $ (656 ) $ (548 ) $ 1,583 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ — $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 12 — 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 — 2,225 — 2,303 Other operating expenses 8 101 — 609 — 718 Depreciation — 22 — 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 41 — 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 255 — 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) — 683 — 427 Income from Group undertakings — (374 ) (93 ) (110 ) 577 — Expenses due to Group undertakings — 200 26 351 (577 ) — Interest expense 43 41 40 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (68 ) 27 447 — 340 (Benefit from)/provision for income taxes — (51 ) 5 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) (17 ) 22 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 443 337 — (1,219 ) — NET INCOME 373 435 359 436 (1,219 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 359 $ 425 $ (1,219 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 400 $ 455 $ (1,316 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 400 $ 454 $ (1,316 ) $ 402
Unaudited Condensed Consolidated Balance Sheet	Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — 4 — 2,242 — 2,246 Prepaid and other current assets — 314 1 264 (149 ) 430 Amounts due from group undertakings 6,202 1,420 2,807 3,626 (14,055 ) — Total current assets 6,204 1,739 2,808 19,314 (14,204 ) 15,861 Investments in subsidiaries 4,506 10,052 1,918 — (16,476 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 146 3 388 (90 ) 447 Non-current amounts due from group undertakings — 4,884 1,775 — (6,659 ) — Total non-current assets 4,506 15,167 3,696 16,513 (23,285 ) 16,597 TOTAL ASSETS $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 — 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 112 33 724 (152 ) 804 Amounts due to group undertakings — 10,467 1,658 1,930 (14,055 ) — Total current liabilities 87 10,605 1,691 16,579 (14,207 ) 14,755 Long-term debt 497 986 2,883 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — 120 — 438 — 558 Other non-current liabilities — 24 — 520 — 544 Non-current amounts due to group undertakings — 519 423 5,717 (6,659 ) — Total non-current liabilities 497 1,649 3,306 8,722 (6,748 ) 7,426 TOTAL LIABILITIES 584 12,254 4,997 25,301 (20,955 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 1,507 10,375 (16,534 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 1,507 10,498 (16,534 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — 7 — 2,073 — 2,080 Prepaid and other current assets — 74 1 324 (62 ) 337 Amounts due from group undertakings 7,229 849 1,595 2,370 (12,043 ) — Total current assets 7,229 930 1,596 16,142 (12,105 ) 13,792 Investments in subsidiaries 3,409 8,621 7,309 — (19,339 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 90 — 310 (47 ) 353 Non-current amounts due from group undertakings — 4,859 1,055 — (5,914 ) — Total non-current assets 3,409 13,668 8,364 16,384 (25,364 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 41 1 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 394 22 92 — 508 Other current liabilities 77 87 33 684 (5 ) 876 Amounts due to group undertakings — 9,946 — 2,097 (12,043 ) — Total current liabilities 77 10,468 56 14,866 (12,097 ) 13,370 Long-term debt 496 186 2,506 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — 120 — 455 — 575 Other non-current liabilities — 63 — 483 (14 ) 532 Non-current amounts due to group undertakings — 518 423 4,973 (5,914 ) — Total non-current liabilities 496 887 2,929 8,414 (6,077 ) 6,649 TOTAL LIABILITIES 573 11,355 2,985 23,280 (18,174 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 6,975 9,077 (19,295 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 6,975 9,195 (19,295 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253
Unaudited Condensed Consolidated Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (8,634 ) — Repayments of intercompany financing activities — (30 ) (118 ) 148 — Net cash (used in)/from financing activities $ (832 ) $ 5,056 $ 3,397 $ (8,396 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 626 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — (857 ) — (857 ) Net disposals of operations — — 44 — 44 Other, net — — 16 — 16 Proceeds from intercompany investing activities 321 136 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (1,226 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — 469 Proceeds from issue of other debt — 592 — — 592 Debt issuance costs — (5 ) — — (5 ) Repayments of debt — (165 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — (82 ) Proceeds from issuance of shares 124 — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — (1 ) — (1 ) Dividends paid (277 ) — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 600 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (640 ) $ 29 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 275 1,076 1,237 (3,630 ) — Repayments of intercompany investing activities — (73 ) (2,676 ) (1,722 ) 4,471 — Reduction in investment in subsidiaries 104 1,288 — 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (570 ) (148 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 912 $ (1,748 ) $ (347 ) $ 841 $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 155 487 — — 642 Senior notes issued — 649 — — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (5 ) (4 ) — — (9 ) Repayments of debt — (394 ) (220 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) (58 ) — (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,920 1,482 1,069 (4,471 ) — Repayments of intercompany financing activities — (2,538 ) (26 ) (1,066 ) 3,630 — Net cash (used in)/from financing activities $ (748 ) $ (271 ) $ 1,719 $ (547 ) $ (632 ) $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 308 $ 152 $ 1,114 $ (621 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) — (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — 33 — 20 (30 ) 23 Proceeds from intercompany investing activities — 108 55 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (3,513 ) (602 ) (769 ) 8,635 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (4,463 ) $ (547 ) $ (4,153 ) $ 8,509 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — — (237 ) — — (237 ) Senior notes issued — — 1,606 — — 1,606 Proceeds from issuance of other debt — — 400 4 — 404 Debt issuance costs — — (14 ) — — (14 ) Repayments of debt (300 ) — (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) (162 ) (302 ) (90 ) 554 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 1 4,266 (8,635 ) — Repayments of intercompany financing activities — (53 ) (22 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,153 $ 395 $ 3,397 $ (7,888 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 593 $ 33 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) — (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 136 — 151 (608 ) — Repayments of intercompany investing activities (82 ) — (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (420 ) (178 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (302 ) $ (924 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings of revolving credit facility — — 469 — — 469 Proceeds from issue of other debt — — 592 — — 592 Debt issuance costs — — (5 ) — — (5 ) Repayments of debt — (149 ) (16 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares and excess tax benefit 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 — 828 (1,009 ) — Repayments of intercompany financing activities — (323 ) (149 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ (291 ) $ 891 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532

Financial Information for Iss53

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Unaudited Condensed Consolidated Statement of Comprehensive Income	Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 2 19 7,866 — 7,887 Costs of providing services Salaries and benefits 2 1 15 4,628 — 4,646 Other operating expenses 3 112 88 1,348 — 1,551 Depreciation — 5 14 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 29 39 125 — 193 Transaction and integration expenses 1 16 26 134 — 177 Total costs of providing services 6 163 182 6,985 — 7,336 (Loss)/income from operations (6 ) (161 ) (163 ) 881 — 551 Income from Group undertakings (3 ) (500 ) (287 ) (136 ) 926 — Expenses due to Group undertakings 3 74 178 671 (926 ) — Interest expense 32 89 39 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 178 (93 ) 293 — 340 (Benefit from)/provision for income taxes — (36 ) (86 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 214 (7 ) 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 234 157 — (849 ) — NET INCOME 420 448 150 269 (849 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 150 $ 251 $ (849 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (266 ) $ (550 ) $ 1,194 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (266 ) $ (548 ) $ 1,194 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 — 48 4,693 — 4,745 Other operating expenses 3 92 20 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 8 15 109 — 132 Transaction and integration expenses — 73 19 177 — 269 Total costs of providing services 7 182 102 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (182 ) (83 ) 1,007 3 738 Income from Group undertakings — (535 ) (219 ) (148 ) 902 — Expenses due to Group undertakings — 62 185 655 (902 ) — Interest expense 30 102 35 21 — 188 Other (income)/expense, net (35 ) — — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 189 (84 ) 621 (235 ) 489 (Benefit from)/provision for income taxes — (51 ) 29 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 240 (113 ) 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 353 171 — (1,094 ) — NET INCOME 568 593 58 702 (1,329 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 58 $ 678 $ (1,329 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 197 $ 1,050 $ (2,163 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 197 $ 1,013 $ (2,163 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 1 11 3,817 — 3,829 Costs of providing services Salaries and benefits 1 — 77 2,225 — 2,303 Other operating expenses 8 100 1 609 — 718 Depreciation — 6 16 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 28 13 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 148 107 3,134 — 3,402 (Loss)/income from operations (13 ) (147 ) (96 ) 683 — 427 Income from Group undertakings — (225 ) (236 ) (110 ) 571 — Expenses due to Group undertakings — 31 189 351 (571 ) — Interest expense 43 39 42 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) 50 (91 ) 447 — 340 (Benefit from)/provision for income taxes — (29 ) (17 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 79 (74 ) 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 347 106 — (892 ) — NET INCOME 373 435 32 436 (892 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 32 $ 425 $ (892 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 49 $ 455 $ (965 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 49 $ 454 $ (965 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ 3,798 $ — $ 3,809 Interest and other income — 1 19 — 20 Total revenues — 12 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 2,225 — 2,303 Other operating expenses 8 101 609 — 718 Depreciation — 22 73 — 95 Amortization — — 76 — 76 Restructuring costs — 41 85 — 126 Transaction and integration expenses 4 14 66 — 84 Total costs of providing services 13 255 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) 683 — 427 Income from Group undertakings — (350 ) (110 ) 460 — Expenses due to Group undertakings — 109 351 (460 ) — Interest expense 43 81 18 — 142 Other expense/(income), net 10 (42 ) (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (41 ) 447 — 340 (Benefit from)/provision for income taxes — (46 ) 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) 5 434 — 373 Interest in earnings of associates, net of tax — 9 2 — 11 Equity account for subsidiaries 439 421 — (860 ) — NET INCOME 373 435 436 (860 ) 384 Income attributable to non-controlling interests — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 425 $ (860 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 455 $ (916 ) $ 403 Comprehensive income attributable to non-controlling interests — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 454 $ (916 ) $ 402 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 7,759 $ — $ 7,778 Interest and other income — 2 107 — 109 Total revenues — 21 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 4,628 — 4,646 Other operating expenses 3 200 1,348 — 1,551 Depreciation — 19 159 — 178 Amortization — — 591 — 591 Restructuring costs — 68 125 — 193 Transaction and integration expenses 1 42 134 — 177 Total costs of providing services 6 345 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) 881 — 551 Income from Group undertakings (3 ) (672 ) (136 ) 811 — Expenses due to Group undertakings 3 137 671 (811 ) — Interest expense 32 128 24 — 184 Other (income)/expense, net — (2 ) 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 85 293 — 340 (Benefit from)/provision for income taxes — (122 ) 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 207 267 — 436 Interest in earnings of associates, net of tax — — 2 — 2 Equity account for subsidiaries 458 241 — (699 ) — NET INCOME 420 448 269 (699 ) 438 Income attributable to non-controlling interests — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 251 $ (699 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (380 ) $ (550 ) $ 928 $ (429 ) Comprehensive loss attributable to non-controlling interests — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (380 ) $ (548 ) $ 928 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ 8,097 $ — $ 8,116 Interest and other income — — 86 — 86 Total revenues — 19 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 4,693 — 4,745 Other operating expenses 3 112 1,419 — 1,534 Depreciation — 6 197 — 203 Amortization — 3 581 (3 ) 581 Restructuring costs — 23 109 — 132 Transaction and integration expenses — 92 177 — 269 Total costs of providing services 7 284 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (265 ) 1,007 3 738 Income from Group undertakings — (645 ) (148 ) 793 — Expenses due to Group undertakings — 138 655 (793 ) — Interest expense 30 137 21 — 188 Other (income)/expense, net (35 ) — (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 105 621 (235 ) 489 Benefit from income taxes — (22 ) (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 127 699 (235 ) 589 Interest in earnings of associates, net of tax — — 3 — 3 Equity account for subsidiaries 570 466 — (1,036 ) — NET INCOME 568 593 702 (1,271 ) 592 Income attributable to non-controlling interests — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 678 $ (1,271 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 1,050 $ (1,966 ) $ 976 Comprehensive income attributable to non-controlling interests — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 1,013 $ (1,966 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 8,097 $ — $ 8,116 Interest and other income — — — 86 — 86 Total revenues — 19 — 8,183 — 8,202 Costs of providing services Salaries and benefits 4 48 — 4,693 — 4,745 Other operating expenses 3 111 1 1,419 — 1,534 Depreciation — 6 — 197 — 203 Amortization — 3 — 581 (3 ) 581 Restructuring costs — 23 — 109 — 132 Transaction and integration expenses — 92 — 177 — 269 Total costs of providing services 7 283 1 7,176 (3 ) 7,464 (Loss)/income from operations (7 ) (264 ) (1 ) 1,007 3 738 Income from Group undertakings — (614 ) (149 ) (148 ) 911 — Expenses due to Group undertakings — 230 26 655 (911 ) — Interest expense 30 34 103 21 — 188 Other (income)/expense, net (35 ) (142 ) 238 61 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (2 ) 86 19 621 (235 ) 489 (Benefit from)/provision for income taxes — (24 ) 2 (78 ) — (100 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (2 ) 110 17 699 (235 ) 589 Interest in earnings of associates, net of tax — — — 3 — 3 Equity account for subsidiaries 570 483 290 — (1,343 ) — NET INCOME 568 593 307 702 (1,578 ) 592 Income attributable to non-controlling interests — — — (24 ) — (24 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 568 $ 593 $ 307 $ 678 $ (1,578 ) $ 568 Comprehensive income before non-controlling interests $ 939 $ 953 $ 663 $ 1,050 $ (2,629 ) $ 976 Comprehensive income attributable to non-controlling interests — — — (37 ) — (37 ) Comprehensive income attributable to Willis Towers Watson $ 939 $ 953 $ 663 $ 1,013 $ (2,629 ) $ 939 Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 19 $ — $ 7,759 $ — $ 7,778 Interest and other income — 2 — 107 — 109 Total revenues — 21 — 7,866 — 7,887 Costs of providing services Salaries and benefits 2 16 — 4,628 — 4,646 Other operating expenses 3 200 — 1,348 — 1,551 Depreciation — 19 — 159 — 178 Amortization — — — 591 — 591 Restructuring costs — 68 — 125 — 193 Transaction and integration expenses 1 42 — 134 — 177 Total costs of providing services 6 345 — 6,985 — 7,336 (Loss)/income from operations (6 ) (324 ) — 881 — 551 Income from Group undertakings (3 ) (657 ) (132 ) (136 ) 928 — Expenses due to Group undertakings 3 228 26 671 (928 ) — Interest expense 32 38 90 24 — 184 Other (income)/expense, net — (2 ) — 29 — 27 (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (38 ) 69 16 293 — 340 (Benefit from)/provision for income taxes — (125 ) 3 26 — (96 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (38 ) 194 13 267 — 436 Interest in earnings of associates, net of tax — — — 2 — 2 Equity account for subsidiaries 458 254 151 — (863 ) — NET INCOME 420 448 164 269 (863 ) 438 Income attributable to non-controlling interests — — — (18 ) — (18 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 420 $ 448 $ 164 $ 251 $ (863 ) $ 420 Comprehensive loss before non-controlling interests $ (427 ) $ (379 ) $ (656 ) $ (550 ) $ 1,583 $ (429 ) Comprehensive loss attributable to non-controlling interests — — — 2 — 2 Comprehensive loss attributable to Willis Towers Watson $ (427 ) $ (379 ) $ (656 ) $ (548 ) $ 1,583 $ (427 ) Condensed Consolidating Statement of Comprehensive Income Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated Revenues Commissions and fees $ — $ 11 $ — $ 3,798 $ — $ 3,809 Interest and other income — 1 — 19 — 20 Total revenues — 12 — 3,817 — 3,829 Costs of providing services Salaries and benefits 1 77 — 2,225 — 2,303 Other operating expenses 8 101 — 609 — 718 Depreciation — 22 — 73 — 95 Amortization — — — 76 — 76 Restructuring costs — 41 — 85 — 126 Transaction and integration expenses 4 14 — 66 — 84 Total costs of providing services 13 255 — 3,134 — 3,402 (Loss)/income from operations (13 ) (243 ) — 683 — 427 Income from Group undertakings — (374 ) (93 ) (110 ) 577 — Expenses due to Group undertakings — 200 26 351 (577 ) — Interest expense 43 41 40 18 — 142 Other expense/(income), net 10 (42 ) — (23 ) — (55 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES (66 ) (68 ) 27 447 — 340 (Benefit from)/provision for income taxes — (51 ) 5 13 — (33 ) (LOSS)/INCOME FROM OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES (66 ) (17 ) 22 434 — 373 Interest in earnings of associates, net of tax — 9 — 2 — 11 Equity account for subsidiaries 439 443 337 — (1,219 ) — NET INCOME 373 435 359 436 (1,219 ) 384 Income attributable to non-controlling interests — — — (11 ) — (11 ) NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON $ 373 $ 435 $ 359 $ 425 $ (1,219 ) $ 373 Comprehensive income before non-controlling interests $ 402 $ 462 $ 400 $ 455 $ (1,316 ) $ 403 Comprehensive income attributable to non-controlling interests — — — (1 ) — (1 ) Comprehensive income attributable to Willis Towers Watson $ 402 $ 462 $ 400 $ 454 $ (1,316 ) $ 402
Unaudited Condensed Consolidated Balance Sheet	Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — — 4 2,242 — 2,246 Prepaid and other current assets — 45 267 264 (146 ) 430 Amounts due from group undertakings 6,202 1,331 1,661 3,626 (12,820 ) — Total current assets 6,204 1,377 1,932 19,314 (12,966 ) 15,861 Investments in subsidiaries 4,506 8,836 6,125 — (19,467 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 34 115 388 (90 ) 447 Non-current amounts due from group undertakings — 5,375 861 — (6,236 ) — Total non-current assets 4,506 14,330 7,101 16,513 (25,853 ) 16,597 TOTAL ASSETS $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 7 19 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 60 83 724 (150 ) 804 Amounts due to group undertakings — 8,100 2,790 1,930 (12,820 ) — Total current liabilities 87 8,167 2,892 16,579 (12,970 ) 14,755 Long-term debt 497 2,883 986 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — — 120 438 — 558 Other non-current liabilities — 5 19 520 — 544 Non-current amounts due to group undertakings — — 519 5,717 (6,236 ) — Total non-current liabilities 497 2,888 1,644 8,722 (6,325 ) 7,426 TOTAL LIABILITIES 584 11,055 4,536 25,301 (19,295 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 4,497 10,375 (19,524 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 4,497 10,498 (19,524 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 15,707 $ 9,033 $ 35,827 $ (38,819 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — — 7 2,073 — 2,080 Prepaid and other current assets — 49 23 324 (59 ) 337 Amounts due from group undertakings 7,229 1,706 1,190 2,370 (12,495 ) — Total current assets 7,229 1,755 1,220 16,142 (12,554 ) 13,792 Investments in subsidiaries 3,409 7,733 5,480 — (16,622 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 10 80 310 (47 ) 353 Non-current amounts due from group undertakings — 4,655 836 — (5,491 ) — Total non-current assets 3,409 12,496 6,396 16,384 (22,224 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 15 27 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 22 394 92 — 508 Other current liabilities 77 94 23 684 (2 ) 876 Amounts due to group undertakings — 8,323 2,075 2,097 (12,495 ) — Total current liabilities 77 8,454 2,519 14,866 (12,546 ) 13,370 Long-term debt 496 2,506 186 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — — 120 455 — 575 Other non-current liabilities — 48 15 483 (14 ) 532 Non-current amounts due to group undertakings — — 518 4,973 (5,491 ) — Total non-current liabilities 496 2,554 839 8,414 (5,654 ) 6,649 TOTAL LIABILITIES 573 11,008 3,358 23,280 (18,200 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 4,258 9,077 (16,578 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 4,258 9,195 (16,578 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,251 $ 7,616 $ 32,526 $ (34,778 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ 1,027 $ — $ 1,030 Fiduciary assets — — 12,155 — 12,155 Accounts receivable, net — 4 2,242 — 2,246 Prepaid and other current assets — 312 264 (146 ) 430 Amounts due from group undertakings 6,202 1,949 3,626 (11,777 ) — Total current assets 6,204 2,266 19,314 (11,923 ) 15,861 Investments in subsidiaries 4,506 10,463 — (14,969 ) — Fixed assets, net — 25 960 — 985 Goodwill — — 10,519 — 10,519 Other intangible assets, net — 60 3,882 (60 ) 3,882 Pension benefits assets — — 764 — 764 Other non-current assets — 149 388 (90 ) 447 Non-current amounts due from group undertakings — 5,717 — (5,717 ) — Total non-current assets 4,506 16,414 16,513 (20,836 ) 16,597 TOTAL ASSETS $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 1,685 — 1,711 Short-term debt and current portion of long-term debt — — 85 — 85 Other current liabilities 87 143 724 (150 ) 804 Amounts due to group undertakings — 9,846 1,930 (11,776 ) — Total current liabilities 87 10,015 16,579 (11,926 ) 14,755 Long-term debt 497 3,869 84 — 4,450 Liability for pension benefits — — 1,259 — 1,259 Deferred tax liabilities — — 704 (89 ) 615 Provision for liabilities — 120 438 — 558 Other non-current liabilities — 24 520 — 544 Non-current amounts due to group undertakings — — 5,717 (5,717 ) — Total non-current liabilities 497 4,013 8,722 (5,806 ) 7,426 TOTAL LIABILITIES 584 14,028 25,301 (17,732 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 10,375 (15,027 ) 10,126 Non-controlling interests — — 123 — 123 Total equity 10,126 4,652 10,498 (15,027 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 18,680 $ 35,827 $ (32,759 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis Towers Watson — the Parent Issuer The Guarantors Other Consolidating adjustments Consolidated ASSETS Cash and cash equivalents $ — $ — $ 870 $ — $ 870 Fiduciary assets — — 10,505 — 10,505 Accounts receivable, net — 7 2,073 — 2,080 Prepaid and other current assets — 72 324 (59 ) 337 Amounts due from group undertakings 7,229 1,648 2,370 (11,247 ) — Total current assets 7,229 1,727 16,142 (11,306 ) 13,792 Investments in subsidiaries 3,409 8,955 — (12,364 ) — Fixed assets, net — 34 805 — 839 Goodwill — — 10,413 — 10,413 Other intangible assets, net — 64 4,368 (64 ) 4,368 Pension benefits assets — — 488 — 488 Other non-current assets — 90 310 (47 ) 353 Non-current amounts due from group undertakings — 4,973 — (4,973 ) — Total non-current assets 3,409 14,116 16,384 (17,448 ) 16,461 TOTAL ASSETS $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 42 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 416 92 — 508 Other current liabilities 77 117 684 (2 ) 876 Amounts due to group undertakings — 9,150 2,097 (11,247 ) — Total current liabilities 77 9,725 14,866 (11,298 ) 13,370 Long-term debt 496 2,692 169 — 3,357 Liability for pension benefits — — 1,321 — 1,321 Deferred tax liabilities — — 1,013 (149 ) 864 Provision for liabilities — 120 455 — 575 Other non-current liabilities — 63 483 (14 ) 532 Non-current amounts due to group undertakings — — 4,973 (4,973 ) — Total non-current liabilities 496 2,875 8,414 (5,136 ) 6,649 TOTAL LIABILITIES 573 12,600 23,280 (16,434 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 9,077 (12,320 ) 10,065 Non-controlling interests — — 118 — 118 Total equity 10,065 3,243 9,195 (12,320 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 15,843 $ 32,526 $ (28,754 ) $ 30,253 Condensed Consolidating Balance Sheet As of December 31, 2017 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Fiduciary assets — — — 12,155 — 12,155 Accounts receivable, net — 4 — 2,242 — 2,246 Prepaid and other current assets — 314 1 264 (149 ) 430 Amounts due from group undertakings 6,202 1,420 2,807 3,626 (14,055 ) — Total current assets 6,204 1,739 2,808 19,314 (14,204 ) 15,861 Investments in subsidiaries 4,506 10,052 1,918 — (16,476 ) — Fixed assets, net — 25 — 960 — 985 Goodwill — — — 10,519 — 10,519 Other intangible assets, net — 60 — 3,882 (60 ) 3,882 Pension benefits assets — — — 764 — 764 Other non-current assets — 146 3 388 (90 ) 447 Non-current amounts due from group undertakings — 4,884 1,775 — (6,659 ) — Total non-current assets 4,506 15,167 3,696 16,513 (23,285 ) 16,597 TOTAL ASSETS $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 12,155 $ — $ 12,155 Deferred revenue and accrued expenses — 26 — 1,685 — 1,711 Short-term debt and current portion of long-term debt — — — 85 — 85 Other current liabilities 87 112 33 724 (152 ) 804 Amounts due to group undertakings — 10,467 1,658 1,930 (14,055 ) — Total current liabilities 87 10,605 1,691 16,579 (14,207 ) 14,755 Long-term debt 497 986 2,883 84 — 4,450 Liability for pension benefits — — — 1,259 — 1,259 Deferred tax liabilities — — — 704 (89 ) 615 Provision for liabilities — 120 — 438 — 558 Other non-current liabilities — 24 — 520 — 544 Non-current amounts due to group undertakings — 519 423 5,717 (6,659 ) — Total non-current liabilities 497 1,649 3,306 8,722 (6,748 ) 7,426 TOTAL LIABILITIES 584 12,254 4,997 25,301 (20,955 ) 22,181 REDEEMABLE NON-CONTROLLING INTEREST — — — 28 — 28 EQUITY Total Willis Towers Watson shareholders’ equity 10,126 4,652 1,507 10,375 (16,534 ) 10,126 Non-controlling interests — — — 123 — 123 Total equity 10,126 4,652 1,507 10,498 (16,534 ) 10,249 TOTAL LIABILITIES AND EQUITY $ 10,710 $ 16,906 $ 6,504 $ 35,827 $ (37,489 ) $ 32,458 Condensed Consolidating Balance Sheet As of December 31, 2016 Willis The Other The Other Consolidating Consolidated ASSETS Cash and cash equivalents $ — $ — $ — $ 870 $ — $ 870 Fiduciary assets — — — 10,505 — 10,505 Accounts receivable, net — 7 — 2,073 — 2,080 Prepaid and other current assets — 74 1 324 (62 ) 337 Amounts due from group undertakings 7,229 849 1,595 2,370 (12,043 ) — Total current assets 7,229 930 1,596 16,142 (12,105 ) 13,792 Investments in subsidiaries 3,409 8,621 7,309 — (19,339 ) — Fixed assets, net — 34 — 805 — 839 Goodwill — — — 10,413 — 10,413 Other intangible assets, net — 64 — 4,368 (64 ) 4,368 Pension benefits assets — — — 488 — 488 Other non-current assets — 90 — 310 (47 ) 353 Non-current amounts due from group undertakings — 4,859 1,055 — (5,914 ) — Total non-current assets 3,409 13,668 8,364 16,384 (25,364 ) 16,461 TOTAL ASSETS $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253 LIABILITIES AND EQUITY Fiduciary liabilities $ — $ — $ — $ 10,505 $ — $ 10,505 Deferred revenue and accrued expenses — 41 1 1,488 (49 ) 1,481 Short-term debt and current portion of long-term debt — 394 22 92 — 508 Other current liabilities 77 87 33 684 (5 ) 876 Amounts due to group undertakings — 9,946 — 2,097 (12,043 ) — Total current liabilities 77 10,468 56 14,866 (12,097 ) 13,370 Long-term debt 496 186 2,506 169 — 3,357 Liability for pension benefits — — — 1,321 — 1,321 Deferred tax liabilities — — — 1,013 (149 ) 864 Provision for liabilities — 120 — 455 — 575 Other non-current liabilities — 63 — 483 (14 ) 532 Non-current amounts due to group undertakings — 518 423 4,973 (5,914 ) — Total non-current liabilities 496 887 2,929 8,414 (6,077 ) 6,649 TOTAL LIABILITIES 573 11,355 2,985 23,280 (18,174 ) 20,019 REDEEMABLE NON-CONTROLLING INTEREST — — — 51 — 51 EQUITY Total Willis Towers Watson shareholders’ equity 10,065 3,243 6,975 9,077 (19,295 ) 10,065 Non-controlling interests — — — 118 — 118 Total equity 10,065 3,243 6,975 9,195 (19,295 ) 10,183 TOTAL LIABILITIES AND EQUITY $ 10,638 $ 14,598 $ 9,960 $ 32,526 $ (37,469 ) $ 30,253
Unaudited Condensed Consolidated Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (725 ) $ 114 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,326 19 1,237 (3,624 ) — Repayments of intercompany investing activities — (994 ) (74 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,188 100 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (503 ) (215 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 1,009 $ (170 ) $ (347 ) $ (834 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 487 155 — — 642 Senior notes issued — — 649 — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (4 ) (5 ) — — (9 ) Repayments of debt — (220 ) (394 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) — (58 ) (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,518 203 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,064 ) (494 ) (1,066 ) 3,624 — Net cash (used in)/from financing activities $ (748 ) $ (283 ) $ 56 $ (547 ) $ 1,043 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 128 $ (83 ) $ 1,114 $ (206 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (79 ) (12 ) (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 163 — 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) — (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,030 ) $ 21 $ (4,153 ) $ 8,508 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — — (237 ) Senior notes issued — 1,606 — — — 1,606 Proceeds from issuance of other debt — 400 — 4 — 404 Debt issuance costs — (14 ) — — — (14 ) Repayments of debt (300 ) (1,037 ) — (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) — (49 ) (90 ) 139 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,204 164 4,266 (8,634 ) — Repayments of intercompany financing activities — (22 ) (53 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,900 $ 62 $ 3,397 $ (8,302 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 583 $ 43 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (10 ) (8 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 49 87 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) — (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — — 598 — Net cash from/(used in) investing activities $ 239 $ (1,305 ) $ 79 $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — — 469 Proceeds from issue of other debt — 592 — — — 592 Debt issuance costs — (5 ) — — — (5 ) Repayments of debt — (16 ) (149 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 154 27 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) — (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 722 $ (122 ) $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (669 ) $ 939 $ (151 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) (292 ) — (300 ) Capitalized software costs — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — (13 ) — (13 ) Net disposals of operations — — 57 — 57 Other, net — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 1,032 1,237 (3,311 ) — Repayments of intercompany investing activities — (1,068 ) (1,722 ) 2,790 — Reduction in investment in subsidiaries 104 1,288 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (718 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 526 $ (347 ) $ (521 ) $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 642 — — 642 Senior notes issued — 649 — — 649 Proceeds from issuance of other debt — — 32 — 32 Debt issuance costs — (9 ) — — (9 ) Repayments of debt — (614 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — (532 ) Proceeds from issuance of shares 61 — — — 61 Payments for share cancellation related to legal settlement — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — (18 ) — (18 ) Dividends paid (277 ) — (151 ) 151 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,721 1,069 (2,790 ) — Repayments of intercompany financing activities — (2,245 ) (1,066 ) 3,311 — Net cash (used in)/from financing activities $ (748 ) $ 144 $ (547 ) $ 672 $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ (4 ) $ 1,114 $ (157 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) (221 ) 94 (218 ) Capitalized software costs — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — 476 — 476 Net disposals of operations — — (4 ) 3 (1 ) Other, net — 33 20 (30 ) 23 Proceeds from intercompany investing activities — 118 30 (148 ) — Repayments of intercompany investing activities (3,751 ) (4,114 ) (769 ) 8,634 — Reduction in investment in subsidiaries 4,600 3,600 — (8,200 ) — Additional investment in subsidiaries — (4,600 ) (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (5,054 ) $ (4,153 ) $ 8,553 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — (237 ) — — (237 ) Senior notes issued — 1,606 — — 1,606 Proceeds from issuance of other debt — 400 4 — 404 Debt issuance costs — (14 ) — — (14 ) Repayments of debt (300 ) (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — (396 ) Proceeds from issuance of shares 63 — — — 63 Payments of deferred and contingent consideration related to acquisitions — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — (13 ) — (13 ) Dividends paid (199 ) — (90 ) 90 (199 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 4,266 (8,634 ) — Repayments of intercompany financing activities — (30 ) (118 ) 148 — Net cash (used in)/from financing activities $ (832 ) $ 5,056 $ 3,397 $ (8,396 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 626 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — (857 ) — (857 ) Net disposals of operations — — 44 — 44 Other, net — — 16 — 16 Proceeds from intercompany investing activities 321 136 151 (608 ) — Repayments of intercompany investing activities (82 ) (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (598 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (1,226 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 469 — — 469 Proceeds from issue of other debt — 592 — — 592 Debt issuance costs — (5 ) — — (5 ) Repayments of debt — (165 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — (82 ) Proceeds from issuance of shares 124 — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — (1 ) — (1 ) Dividends paid (277 ) — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 828 (1,009 ) — Repayments of intercompany financing activities — (472 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ 600 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ 527 $ — $ 532 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2017 Willis The Other The Other Consolidating Consolidated NET CASH FROM/(USED IN) OPERATING ACTIVITIES $ 743 $ (640 ) $ 29 $ 939 $ (209 ) $ 862 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (8 ) — (292 ) — (300 ) Capitalized software costs — — — (75 ) — (75 ) Acquisitions of operations, net of cash acquired — — — (13 ) — (13 ) Net disposals of operations — — — 57 — 57 Other, net — — — (4 ) — (4 ) Proceeds from intercompany investing activities 1,042 275 1,076 1,237 (3,630 ) — Repayments of intercompany investing activities — (73 ) (2,676 ) (1,722 ) 4,471 — Reduction in investment in subsidiaries 104 1,288 — 618 (2,010 ) — Additional investment in subsidiaries (1,139 ) (570 ) (148 ) (153 ) 2,010 — Net cash from/(used in) investing activities $ 7 $ 912 $ (1,748 ) $ (347 ) $ 841 $ (335 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings on revolving credit facility — 155 487 — — 642 Senior notes issued — 649 — — — 649 Proceeds from issuance of other debt — — — 32 — 32 Debt issuance costs — (5 ) (4 ) — — (9 ) Repayments of debt — (394 ) (220 ) (120 ) — (734 ) Repurchase of shares (532 ) — — — — (532 ) Proceeds from issuance of shares 61 — — — — 61 Payments for share cancellation related to legal settlement — — — (177 ) — (177 ) Payments of deferred and contingent consideration related to acquisitions — — — (65 ) — (65 ) Cash paid for employee taxes on withholding shares — — — (18 ) — (18 ) Dividends paid (277 ) (58 ) — (151 ) 209 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (51 ) — (51 ) Proceeds from intercompany financing activities — 1,920 1,482 1,069 (4,471 ) — Repayments of intercompany financing activities — (2,538 ) (26 ) (1,066 ) 3,630 — Net cash (used in)/from financing activities $ (748 ) $ (271 ) $ 1,719 $ (547 ) $ (632 ) $ (479 ) INCREASE IN CASH AND CASH EQUIVALENTS 2 1 — 45 — 48 Effect of exchange rate changes on cash and cash equivalents — — — 112 — 112 CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR — — — 870 — 870 CASH AND CASH EQUIVALENTS, END OF YEAR $ 2 $ 1 $ — $ 1,027 $ — $ 1,030 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2016 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (20 ) $ 308 $ 152 $ 1,114 $ (621 ) $ 933 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (91 ) — (221 ) 94 (218 ) Capitalized software costs — — — (85 ) — (85 ) Acquisitions of operations, net of cash acquired — — — 476 — 476 Net disposals of operations — — — (4 ) 3 (1 ) Other, net — 33 — 20 (30 ) 23 Proceeds from intercompany investing activities — 108 55 30 (193 ) — Repayments of intercompany investing activities (3,751 ) (3,513 ) (602 ) (769 ) 8,635 — Reduction in investment in subsidiaries 4,600 3,600 — — (8,200 ) — Additional investment in subsidiaries — (4,600 ) — (3,600 ) 8,200 — Net cash from/(used in) investing activities $ 849 $ (4,463 ) $ (547 ) $ (4,153 ) $ 8,509 $ 195 CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net payments on revolving credit facility — — (237 ) — — (237 ) Senior notes issued — — 1,606 — — 1,606 Proceeds from issuance of other debt — — 400 4 — 404 Debt issuance costs — — (14 ) — — (14 ) Repayments of debt (300 ) — (1,037 ) (564 ) — (1,901 ) Repurchase of shares (396 ) — — — — (396 ) Proceeds from issuance of shares 63 — — — — 63 Payments of deferred and contingent consideration related to acquisitions — — — (67 ) — (67 ) Cash paid for employee taxes on withholding shares — — — (13 ) — (13 ) Dividends paid (199 ) (162 ) (302 ) (90 ) 554 (199 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 4,368 1 4,266 (8,635 ) — Repayments of intercompany financing activities — (53 ) (22 ) (118 ) 193 — Net cash (used in)/from financing activities $ (832 ) $ 4,153 $ 395 $ 3,397 $ (7,888 ) $ (775 ) (DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS (3 ) (2 ) — 358 — 353 Effect of exchange rate changes on cash and cash equivalents — — — (15 ) — (15 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 3 2 — 527 — 532 CASH AND CASH EQUIVALENTS, END OF YEAR $ — $ — $ — $ 870 $ — $ 870 Condensed Consolidating Statement of Cash Flows Year ended December 31, 2015 Willis The Other The Other Consolidating Consolidated NET CASH (USED IN)/FROM OPERATING ACTIVITIES $ (10 ) $ 593 $ 33 $ (222 ) $ (150 ) $ 244 CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES Additions to fixed assets and software for internal use — (18 ) — (128 ) — (146 ) Acquisitions of operations, net of cash acquired — — — (857 ) — (857 ) Net disposals of operations — — — 44 — 44 Other, net — — — 16 — 16 Proceeds from intercompany investing activities 321 136 — 151 (608 ) — Repayments of intercompany investing activities (82 ) — (746 ) (181 ) 1,009 — Additional investment in subsidiaries — (420 ) (178 ) — 598 — Net cash from/(used in) investing activities $ 239 $ (302 ) $ (924 ) $ (955 ) $ 999 $ (943 ) CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES Net borrowings of revolving credit facility — — 469 — — 469 Proceeds from issue of other debt — — 592 — — 592 Debt issuance costs — — (5 ) — — (5 ) Repayments of debt — (149 ) (16 ) (1 ) — (166 ) Repurchase of shares (82 ) — — — — (82 ) Proceeds from issuance of shares and excess tax benefit 124 — — 605 (598 ) 131 Cash paid for employee taxes on withholding shares — — — (1 ) — (1 ) Dividends paid (277 ) — — (150 ) 150 (277 ) Acquisitions of and dividends paid to non-controlling interests — — — (21 ) — (21 ) Proceeds from intercompany financing activities — 181 — 828 (1,009 ) — Repayments of intercompany financing activities — (323 ) (149 ) (136 ) 608 — Net cash (used in)/from financing activities $ (235 ) $ (291 ) $ 891 $ 1,124 $ (849 ) $ 640 DECREASE IN CASH AND CASH EQUIVALENTS (6 ) — — (53 ) — (59 ) Effect of exchange rate changes on cash and cash equivalents — — — (44 ) — (44 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 9 2 — 624 — 635 CASH AND CASH EQUIVALENTS, END OF YEAR $ 3 $ 2 $ — $ 527 $ — $ 532

Nature of Operations (Details)

Nature of Operations (Details)	Dec. 31, 2017employeeCountry
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of employees employed (more than 41,000) | employee	43,000
Number of countries in which entity operates (more than 140) | Country	140

Basis of Basis of Presentatio55

Basis of Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements - Additional Information (Details)	Jan. 04, 2016	Sep. 30, 2017unit	Dec. 31, 2017USD ($)arrangement	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jan. 01, 2018USD ($)	Jan. 01, 2017USD ($)
Deferred Revenue Arrangement [Line Items]
Number of reporting units | unit		9
Number of fixed-fee arrangements | arrangement			4
NET CASH FROM/(USED IN) OPERATING ACTIVITIES			$ 862,000,000	$ 933,000,000	$ 244,000,000
Accounting Standards Update 2016-09 [Member]
Deferred Revenue Arrangement [Line Items]
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount			7,000,000
NET CASH FROM/(USED IN) OPERATING ACTIVITIES			$ 7,000,000	(13,000,000)	$ (1,000,000)
Accounting Standards Update 2016-16 [Member]
Deferred Revenue Arrangement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(3,000,000)
Delivered software, initial license and maintenance
Deferred Revenue Arrangement [Line Items]
Initial contract term used to recognize fees			1 year
Minimum | Accounting Standards Codification 606 [Member]
Deferred Revenue Arrangement [Line Items]
Deferred costs, amortization period			3 years
Maximum | Accounting Standards Codification 606 [Member]
Deferred Revenue Arrangement [Line Items]
Deferred costs, amortization period			5 years
Internally developed software | Minimum
Deferred Revenue Arrangement [Line Items]
Useful life			3 years
Internally developed software | Maximum
Deferred Revenue Arrangement [Line Items]
Useful life			10 years
Buildings
Deferred Revenue Arrangement [Line Items]
Useful life			50 years
Furniture, equipment and software | Minimum
Deferred Revenue Arrangement [Line Items]
Useful life			3 years
Furniture, equipment and software | Maximum
Deferred Revenue Arrangement [Line Items]
Useful life			10 years
Retained earnings | Accounting Standards Update 2016-16 [Member]
Deferred Revenue Arrangement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ (3,000,000)			$ (3,000,000)
Retained earnings | Minimum | Accounting Standards Codification 606 [Member]
Deferred Revenue Arrangement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption						$ (375,000,000)
Retained earnings | Maximum | Accounting Standards Codification 606 [Member]
Deferred Revenue Arrangement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption						$ (475,000,000)
Common Stock
Deferred Revenue Arrangement [Line Items]
Reverse stock split	0.3775
Willis Limited
Deferred Revenue Arrangement [Line Items]
Unencumbered and available funds required			$ 140,000,000
Unencumbered and available cash balance required			$ 79,000,000

Basis of Basis of Presentatio56

Basis of Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements - Finite-lived Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2017
Product
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	17 years 6 months
Favorable agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	7 years
Management contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	18 years
Minimum | Client relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	5 years
Minimum | Software
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	4 years
Minimum | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	14 years
Maximum | Client relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	20 years
Maximum | Software
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	7 years
Maximum | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Expected life	25 years

Merger, Acquisitions and Dive57

Merger, Acquisitions and Divestitures - Narrative (Details) $ / shares in Units, € in Millions	Jan. 04, 2016USD ($)$ / sharesshares	Dec. 29, 2015USD ($)$ / sharesshares	Dec. 29, 2015EUR (€)	Nov. 20, 2015	May 31, 2015USD ($)	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)	Dec. 29, 2015EUR (€)shares
Business Acquisition [Line Items]
Business Combination, Deferred And Contingent Consideration						$ 96,000,000	$ 96,000,000
Goodwill						10,519,000,000	10,519,000,000	$ 10,413,000,000	$ 3,737,000,000
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal							13,000,000	2,000,000	$ 25,000,000
Towers Watson & Co.
Business Acquisition [Line Items]
Duration that entity has been in existence (more than)	100 years
Conversion of Towers Watson stock to Willis stock, conversion ratio	2.6490
Dividends paid per share (usd per share) | $ / shares		$ 10
Dividends paid		$ 694,000,000
Common shares outstanding | shares	69,000,000	69,000,000								69,000,000
Revenue of acquiree since acquisition date, actual								3,600,000,000
Earnings or acquiree since acquisition date, actual								111,000,000
Value of equity awards assumed	$ 37,000,000
Total consideration	8,723,000,000
Intangible assets	3,991,000,000
Goodwill	$ 6,783,000,000
Towers Watson & Co. | Stock options
Business Acquisition [Line Items]
Number of awards converted from acquiree to acquirer | shares	592,486
Value of equity awards assumed	$ 7,000,000
Fair value of outstanding options related to post-acquistion employee service	$ 13,000,000
Towers Watson & Co. | Restricted Stock Units
Business Acquisition [Line Items]
Number of awards converted from acquiree to acquirer | shares	597,307
Value of equity awards assumed	$ 30,000,000
Fair value of outstanding units related to post-acquistion employee service	$ 32,000,000
Gras Savoye
Business Acquisition [Line Items]
Goodwill, tax deductible		$ 0
Percentage of interest acquired		70.00%								70.00%
Total consideration		$ 592,000,000	€ 544			3,000,000
Consideration paid in cash		582,000,000
Fair value of deferred consideration								$ 4,000,000
Remeasurement fair value of previously held interest in acquisition		$ 241,000,000								€ 221
Total basis in acquiree		100.00%								100.00%
Fair value basis of acquisition		$ 833,000,000								€ 765
Deferred consideration, payment period one		1 year	1 year
Deferred consideration, payment period two		2 years	2 years
Intangible assets		$ 440,000,000
Goodwill		$ 584,000,000
Miller Insurance Services LLP
Business Acquisition [Line Items]
Percentage of interest acquired					85.00%
Total consideration					$ 401,000,000
Consideration paid in cash					$ 232,000,000
Fair value of deferred consideration						38,000,000	38,000,000
Fair value of contingent consideration						40,000,000	40,000,000
Discounted fair value of contingent consideration liability						$ 78,000,000	$ 78,000,000
Deferred consideration, payment period one					1 year
Deferred consideration, payment period two					2 years
Deferred consideration, payment period three					3 years
Contingent consideration, period for payment one					3 years
Assets recognized					$ 1,100,000,000
Liabilities assumed					844,000,000
Intangible assets					231,000,000
Goodwill					$ 184,000,000
Ordinary shares, $0.000304635 nominal value
Business Acquisition [Line Items]
Ordinary shares, nominal value (usd and Euro per share) | $ / shares	$ 0.000304635000					$ 0.000304635	$ 0.000304635	$ 0.000304635
Common shares outstanding | shares						132,139,581	132,139,581	136,296,771
Ordinary shares, $0.000304635 nominal value | Towers Watson & Co.
Business Acquisition [Line Items]
Conversion of Towers Watson stock to Willis stock, conversion ratio	2.6490
Ordinary shares, $0.000115 nominal value | Towers Watson & Co.
Business Acquisition [Line Items]
Ordinary shares, nominal value (usd and Euro per share) | $ / shares	$ 0.000115
Line of Credit | 1-year term loan facility matures 2016 | Term Loan
Business Acquisition [Line Items]
Term loan period		1 year	1 year	1 year
second [Member] | Miller Insurance Services LLP
Business Acquisition [Line Items]
Business Combination, Deferred And Contingent Consideration								$ 69,000,000
Third [Member] | Miller Insurance Services LLP
Business Acquisition [Line Items]
Business Combination, Deferred And Contingent Consideration								$ 26,000,000

Merger, Acquisitions and Dive58

Merger, Acquisitions and Divestitures - Preliminary Calculation of Aggregate Merger Consideration (Details) $ / shares in Units, € in Millions, shares in Millions, $ in Millions	Jan. 04, 2016USD ($)$ / sharesshares	Dec. 29, 2015USD ($)shares	Dec. 29, 2015EUR (€)shares	Dec. 31, 2017USD ($)
Towers Watson & Co.
Business Acquisition [Line Items]
Number of shares of Towers Watson common stock outstanding as of January 4, 2016 | shares	69	69	69
Exchange ratio	2.6490
Fair value of 184 million Willis ordinary shares	$ 8,686
Value of equity awards assumed	37
Aggregate Merger consideration	$ 8,723
Towers Watson & Co. | Willis Group Holdings
Business Acquisition [Line Items]
Number of Willis Group Holdings shares issued (prior to reverse stock split) | shares	184
Willis Group Holdings price per share on January 4, 2016 | $ / shares	$ 47.18
Gras Savoye
Business Acquisition [Line Items]
Aggregate Merger consideration		$ 592	€ 544	$ 3
Towers Watson Debt, Due on Change of Control | Towers Watson & Co.
Business Acquisition [Line Items]
Repayments of debt	$ 400

Merger, Acquisitions and Dive59

Merger, Acquisitions and Divestitures - Schedule of Fair Values of the Identifiable Assets Acquired and Liabilities Assumed (Details) € in Millions, $ in Millions		Jan. 04, 2016USD ($)	Dec. 29, 2015USD ($)	Dec. 29, 2015EUR (€)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 29, 2015EUR (€)
Business Acquisition [Line Items]
Goodwill					$ 10,519	$ 10,413	$ 3,737
Towers Watson & Co.
Business Acquisition [Line Items]
Cash and cash equivalents		$ 476
Accounts receivable, net		825
Other current assets		82
Fixed assets, net		204
Goodwill		6,783
Intangible assets		3,991
Pension benefits assets		67
Other non-current assets		115
Deferred tax liabilities		(1,151)
Liability for pension benefits		(923)
Other current liabilities	[1]	(667)
Other non-current liabilities	[2]	(331)
Short and long-term debt	[3]	(740)
Net assets acquired		8,731
Non-controlling interest acquired		(8)
Allocated aggregate Merger consideration		8,723
Dividends paid			$ 694
Towers Watson & Co. | Towers Watson Debt, Due on Change of Control
Business Acquisition [Line Items]
Short and long-term debt		(400)
Repayments of debt		400
Towers Watson & Co. | Towers Watson Debt, Due on Change of Control | Term Loan
Business Acquisition [Line Items]
Short and long-term debt		(188)
Towers Watson & Co. | Towers Watson Debt, Due on Change of Control | Line of Credit | Revolving Credit Facility
Business Acquisition [Line Items]
Short and long-term debt		(212)
Towers Watson & Co. | Towers Watson New Term Loan | Term Loan
Business Acquisition [Line Items]
Proceeds from issuance of debt			340
Gras Savoye
Business Acquisition [Line Items]
Cash and cash equivalents			87
Fiduciary assets			625
Accounts receivable, net			89
Goodwill			584
Intangible assets			440
Other non-current assets			56
Fiduciary liabilities			(625)
Deferred revenue and accrued expenses			(80)
Deferred tax liabilities			(87)
Other non-current liabilities			(179)
Short and long-term debt			(80)
Net assets acquired			830
Decrease in paid-in capital for purchase of non-controlling interest			43
Non-controlling interest acquired			(40)
Allocated aggregate Merger consideration			592	€ 544	$ 3
Purchase price allocation			$ 833					€ 765
Towers Watson Accounts Payable, Accrued Liabilities, and Deferred Compensation | Towers Watson & Co.
Business Acquisition [Line Items]
Other current liabilities		(348)
Towers Watson Employee-related Liabilities | Towers Watson & Co.
Business Acquisition [Line Items]
Other current liabilities		(308)
Towers Watson Other Current Liabilities | Towers Watson & Co.
Business Acquisition [Line Items]
Other current liabilities		(11)
Towers Watson Acquired Contingent Liabilities | Towers Watson & Co.
Business Acquisition [Line Items]
Other non-current liabilities		$ (242)
[1]	Includes $348 million in accounts payable, accrued liabilities and deferred revenue, $308 million in employee-related liabilities and $11 million in other current liabilities.
[2]	Includes acquired contingent liabilities of $242 million. See Note 13 — Commitments and Contingencies for a discussion of our material acquired contingencies related to Legacy Towers Watson.
[3]	Represents both debt due upon change of control of $400 million borrowed under Towers Watson’s term loan ($188 million) and revolving credit facility ($212 million) and a draw down under a new term loan of $340 million. The $400 million debt was repaid by Willis’ borrowings under the 1-year term loan facility on January 4, 2016. The $340 million new term loan partially funded the $694 million Towers Watson pre-merger special dividend.

Merger, Acquisitions and Dive60

Merger, Acquisitions and Divestitures - Unaudited Pro Forma Financial Information (Details) - Towers Watson & Co. - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Total revenues	$ 7,887	$ 7,492
Net income attributable to Willis Towers Watson	$ 420	$ 640
Diluted earnings per share (in dollars per share)	$ 3.04	$ 4.64

Merger, Acquisitions and Dive61

Merger, Acquisitions and Divestitures - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Millions		Jan. 04, 2016	Dec. 29, 2015	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 50	$ 3,953
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				13	2,222
Product
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 0	42
Expected Life (Years)				17 years 6 months
Favorable agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 1	$ 11
Towers Watson & Co.
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 3,991
Towers Watson & Co. | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 2,221
Expected Life (Years)		15 years
Towers Watson & Co. | Software | Income Approach Valuation Technique
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 567
Expected Life (Years)		6 years 5 months
Towers Watson & Co. | Software | Cost Approach Valuation Technique
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 108
Expected Life (Years)		4 years 11 months
Towers Watson & Co. | Product
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 42
Expected Life (Years)		17 years 6 months
Towers Watson & Co. | IPR&D
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	[1]	$ 39
Towers Watson & Co. | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 1,003
Expected Life (Years)		25 years
Towers Watson & Co. | Favorable agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired		$ 11
Expected Life (Years)		6 years 6 months
Gras Savoye
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 440
Gras Savoye | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 339
Expected Life (Years)			20 years
Gras Savoye | Software and other intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 66
Expected Life (Years)			5 years
Gras Savoye | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 35
Expected Life (Years)			14 years
[1]	Represents individual in-process research and development (‘IPR&D’) software components not placed into service as of the acquisition date. These assets were subsequently placed into service during the three months ended March 31, 2017, were reclassified into finite-lived software intangible assets, and are being amortized in line with underlying cash flows or on a straight-line basis.

Merger, Acquisitions and Dive62

Merger, Acquisitions and Divestitures - Global Wealth Solutions Divestiture (Details) - Affiliated Entity [Member] $ in Millions	3 Months Ended
	Sep. 30, 2017USD ($)
Global Wealth Solutions Transaction [Line Items]
Global Wealth Solutions Transaction, Amounts of Transaction	$ 50
Global Wealth Solutions Transaction, Related Party Loan Collateral	$ 3
Global Wealth Solutions Transaction, Rate	3.00%
Global Wealth Solutions Transaction, Loan Receivable Term	10

Merger, Acquisitions and Dive63

Merger, Acquisitions and Divestitures - All divestitures (Details) $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Dispositions [Line Items]
Dispositions, Number of Businesses	5
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ 13	$ 2	$ 25
Dispositions, Revenue prior to Sales		54
Dispositions, Operating Income prior to Sales		$ 13

Segment Information - Narrative

Segment Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Reporting [Abstract]
Number of reportable segments	4

Segment Information - Revenue (

Segment Information - Revenue (Net of Reimbursable Expenses) of the Reported Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Commissions and fees									$ 8,116	$ 7,778	$ 3,809
Interest and other income									86	109	20
Income from operations	$ 110	$ 41	$ 124	$ 463	$ 88	$ 1	$ 136	$ 326	738	551	427
Operating Segments
Segment Reporting Information [Line Items]
Commissions and fees									8,022	7,746	3,810
Interest and other income									82	106	19
Total segment revenues									8,104	7,852	3,829
Income from operations									1,786	1,693	783
Operating Segments | HCB
Segment Reporting Information [Line Items]
Commissions and fees									3,163	3,100	583
Interest and other income									29	17	1
Total segment revenues									3,192	3,117	584
Income from operations									781	728	119
Operating Segments | CRB
Segment Reporting Information [Line Items]
Commissions and fees									2,625	2,519	2,332
Interest and other income									23	28	17
Total segment revenues									2,648	2,547	2,349
Income from operations									488	463	457
Operating Segments | IRR
Segment Reporting Information [Line Items]
Commissions and fees									1,505	1,475	895
Interest and other income									30	59	1
Total segment revenues									1,535	1,534	896
Income from operations									365	383	207
Operating Segments | BDA
Segment Reporting Information [Line Items]
Commissions and fees									729	652	0
Interest and other income									0	2	0
Total segment revenues									729	654	0
Income from operations									$ 152	$ 119	$ 0

Segment Information - Reconcili

Segment Information - Reconciliation of Information Reported by Segment to Consolidated Amounts (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Fair value adjustment to deferred revenue										$ 0	$ (58)	$ 0
Total revenues		$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	8,202	7,887	3,829
Income from operations		$ 110	$ 41	$ 124	$ 463	$ 88	$ 1	$ 136	$ 326	738	551	427
Amortization										(581)	(591)	(76)
Restructuring costs										(132)	(193)	(126)
Transaction and integration expenses	[1]									(269)	(177)	(73)
Provision for Stanford and other significant litigation										(11)	(50)	(70)
Pension settlement and curtailment gains and losses										(36)	0	0
Unallocated, net (ii)	[2]									(19)	(73)	(11)
Interest expense										188	184	142
Other expense/(income), net										61	27	(55)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES										489	340	340
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment revenues										8,104	7,852	3,829
Income from operations										1,786	1,693	783
Segment Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Fair value adjustment to deferred revenue										0	(58)	0
Reimbursable expenses and other										$ 98	$ 93	$ 0
[1]	Includes transaction and integration expenses related to the Merger and the acquisition of Gras Savoye.
[2]	Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.

Segment Information - Revenue a

Segment Information - Revenue and Long-Lived Assets by Geographical Areas (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenues		$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	$ 8,202	$ 7,887	$ 3,829
Long-Lived Assets	[1]	16,551				16,411				16,551	16,411	6,260
Ireland
Segment Reporting Information [Line Items]
Total revenues										107	92	64
Long-Lived Assets	[1]	127				114				127	114	124
United States
Segment Reporting Information [Line Items]
Total revenues										3,821	3,395	1,597
Long-Lived Assets	[1]	9,988				11,400				9,988	11,400	1,759
United Kingdom
Segment Reporting Information [Line Items]
Total revenues										1,815	2,236	1,055
Long-Lived Assets	[1]	3,173				2,431				3,173	2,431	2,426
Rest of World
Segment Reporting Information [Line Items]
Total revenues										2,459	2,164	1,113
Long-Lived Assets	[1]	3,263				2,466				3,263	2,466	1,951
Total Foreign Countries
Segment Reporting Information [Line Items]
Total revenues										8,095	7,795	3,765
Long-Lived Assets	[1]	$ 16,424				$ 16,297				$ 16,424	$ 16,297	$ 6,136
[1]	Long-Lived Assets do not include deferred tax assets.

Restructuring Costs - Narrative

Restructuring Costs - Narrative (Details) $ in Millions		12 Months Ended
		Dec. 31, 2017USD ($)employeeprogram	Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Restructuring Cost and Reserve [Line Items]
Number of restructuring programs | program		2
Number of support roles moved from higher cost locations to lower cost locations (more than) | employee		3,500
Restructuring costs		$ (132)	$ (193)		$ (126)
Operational Improvement Program
Restructuring Cost and Reserve [Line Items]
Restructuring costs		(134)	(145)		(126)	$ (36)
Restructuring and Related Cost, Cost Incurred to Date		441
Business Restructure Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		2	(48)
Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		(46)	(68)		(36)
Termination benefits | Operational Improvement Program
Restructuring Cost and Reserve [Line Items]
Restructuring costs		(48)	(23)		(36)	(16)
Restructuring and Related Cost, Cost Incurred to Date		123
Termination benefits | Business Restructure Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		2	(45)
Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	(86)	(125)		(90)
Professional services and other | Operational Improvement Program
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	(86)	(122)		$ (90)	$ (20)
Restructuring and Related Cost, Cost Incurred to Date	[1]	318
Professional services and other | Business Restructure Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 0	$ (3)	[1]
[1]	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs.

Restructuring Costs - Analysis

Restructuring Costs - Analysis of the Cost for Restructuring (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 132		$ 193		$ 126
Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		46		68		36
Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	86		125		90
Operating Segments | HCB
Restructuring Cost and Reserve [Line Items]
Restructuring costs		3		37		3
Operating Segments | HCB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		33		2
Operating Segments | HCB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	3		4		1
Operating Segments | CRB
Restructuring Cost and Reserve [Line Items]
Restructuring costs		88		107		81
Operating Segments | CRB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		25		26		24
Operating Segments | CRB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	63		81		57
Operating Segments | IRR
Restructuring Cost and Reserve [Line Items]
Restructuring costs		10		10		9
Operating Segments | IRR | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		4		6		7
Operating Segments | IRR | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	6		4		2
Operating Segments | BDA
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		1		0
Operating Segments | BDA | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		1		0
Operating Segments | BDA | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		0		0	[1]
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs		31		38		33
Corporate | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		17		2		3
Corporate | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	14		36		30
Operational Improvement Program
Restructuring Cost and Reserve [Line Items]
Restructuring costs		134		145		126		$ 36
Restructuring and Related Cost, Cost Incurred to Date		441
Operational Improvement Program | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		48		23		36		16
Restructuring and Related Cost, Cost Incurred to Date		123
Operational Improvement Program | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	86		122		90		20
Restructuring and Related Cost, Cost Incurred to Date	[1]	318
Operational Improvement Program | Operating Segments | HCB
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		8
Operational Improvement Program | Operating Segments | HCB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		1		2		0
Restructuring and Related Cost, Cost Incurred to Date		3
Operational Improvement Program | Operating Segments | HCB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		3	[1]	1	[1]	1	[1]	0
Restructuring and Related Cost, Cost Incurred to Date	[1]	5
Operational Improvement Program | Operating Segments | CRB
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		286
Operational Improvement Program | Operating Segments | CRB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		25		18		24		15
Restructuring and Related Cost, Cost Incurred to Date		82
Operational Improvement Program | Operating Segments | CRB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	63		81		57		3
Restructuring and Related Cost, Cost Incurred to Date	[1]	204
Operational Improvement Program | Operating Segments | IRR
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		27
Operational Improvement Program | Operating Segments | IRR | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		4		3		7		1
Restructuring and Related Cost, Cost Incurred to Date		15
Operational Improvement Program | Operating Segments | IRR | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		6	[1]	4	[1]	2	[1]	0
Restructuring and Related Cost, Cost Incurred to Date	[1]	12
Operational Improvement Program | Operating Segments | BDA
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		0
Operational Improvement Program | Operating Segments | BDA | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		0		0		0
Restructuring and Related Cost, Cost Incurred to Date		0
Operational Improvement Program | Operating Segments | BDA | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0		0		0		0
Restructuring and Related Cost, Cost Incurred to Date		0
Operational Improvement Program | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		120
Operational Improvement Program | Corporate | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		19		1		3		0
Restructuring and Related Cost, Cost Incurred to Date		23
Operational Improvement Program | Corporate | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]	14		36		$ 30		$ 17
Restructuring and Related Cost, Cost Incurred to Date	[1]	97
Business Restructure Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		(2)		48
Business Restructure Program [Member] | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs		(2)		45
Business Restructure Program [Member] | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 0		3	[1]
Business Restructure Program [Member] | Operating Segments | HCB
Restructuring Cost and Reserve [Line Items]
Restructuring costs				35
Business Restructure Program [Member] | Operating Segments | HCB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs				32
Business Restructure Program [Member] | Operating Segments | HCB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[1]			3
Business Restructure Program [Member] | Operating Segments | CRB
Restructuring Cost and Reserve [Line Items]
Restructuring costs				8
Business Restructure Program [Member] | Operating Segments | CRB | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs				8
Business Restructure Program [Member] | Operating Segments | CRB | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs				0
Business Restructure Program [Member] | Operating Segments | IRR
Restructuring Cost and Reserve [Line Items]
Restructuring costs				3
Business Restructure Program [Member] | Operating Segments | IRR | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs				3
Business Restructure Program [Member] | Operating Segments | IRR | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs				0
Business Restructure Program [Member] | Operating Segments | BDA
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1
Business Restructure Program [Member] | Operating Segments | BDA | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1
Business Restructure Program [Member] | Operating Segments | BDA | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs				0
Business Restructure Program [Member] | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1
Business Restructure Program [Member] | Corporate | Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1
Business Restructure Program [Member] | Corporate | Professional services and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs				$ 0
[1]	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs.

Restructuring Costs - Restructu

Restructuring Costs - Restructuring Liability (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Charges incurred		$ (132)	$ (193)		$ (126)
Operational Improvement Program
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		25	26		11	$ 0
Charges incurred		(134)	(145)		(126)	(36)
Cash payments		(138)	(146)		(111)	(25)
Restructuring liability, ending balance		21	25		26	11
Business Restructure Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		26	0
Charges incurred		2	(48)
Cash payments		(23)	(22)
Restructuring liability, ending balance		1	26		0
Termination benefits
Restructuring Reserve [Roll Forward]
Charges incurred		(46)	(68)		(36)
Termination benefits | Operational Improvement Program
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		7	15		5	0
Charges incurred		(48)	(23)		(36)	(16)
Cash payments		(41)	(31)		(26)	(11)
Restructuring liability, ending balance		14	7		15	5
Termination benefits | Business Restructure Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		26	0
Charges incurred		2	(45)
Cash payments		(23)	(19)
Restructuring liability, ending balance		1	26		0
Professional services and other
Restructuring Reserve [Roll Forward]
Charges incurred	[1]	(86)	(125)		(90)
Professional services and other | Operational Improvement Program
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		18	11		6	0
Charges incurred	[1]	(86)	(122)		(90)	(20)
Cash payments		(97)	(115)		(85)	(14)
Restructuring liability, ending balance		7	18		11	$ 6
Professional services and other | Business Restructure Program [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance		0	0
Charges incurred		0	(3)	[1]
Cash payments		0	(3)
Restructuring liability, ending balance		$ 0	$ 0		$ 0
[1]	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs.

Income Taxes - Income (Loss) Be

Income Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	$ 489	$ 340	$ 340
Revenue Commissioners, Ireland | Domestic Tax Authority
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(23)	(27)	(61)
Internal Revenue Service (IRS) | Foreign Tax Authority
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(198)	(311)	(67)
Her Majesty's Revenue and Customs (HMRC) | Foreign Tax Authority
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	31	123	65
Other jurisdictions | Foreign Tax Authority
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	$ 679	$ 555	$ 403

Income Taxes - Current and Defe

Income Taxes - Current and Deferred Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current tax expense/(benefit):
U.S. federal taxes	$ 65	$ 35	$ 14
U.S. state and local taxes	7	14	1
U.K. corporation tax	14	28	0
Other jurisdictions	99	71	51
Total current income tax expense (benefit)	185	148	66
Deferred tax expense/(benefit):
U.S. federal taxes	(268)	(214)	(113)
U.S. state and local taxes	6	(5)	(3)
U.K. corporation tax	(9)	10	14
Other jurisdictions	(14)	(35)	3
Total deferred tax benefit	(285)	(244)	(99)
Total benefit from income taxes	$ (100)	$ (96)	$ (33)

Income Taxes - Effective Tax Ra

Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	$ 489	$ 340	$ 340
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
Income tax expense at U.S. federal tax rate	$ 171	$ 119	$ 119
Non-deductible expenses and dividends	68	15	32
Non-deductible acquisition costs	11	1	9
Disposal of non-deductible goodwill	11	2	3
Gain on re-measurement of equity interests	0	0	20
Impact of change in rate on deferred tax balances	0	(15)	(5)
Effect of foreign exchange and other differences	3	6	(1)
Non-deductible Venezuelan foreign exchange loss	2	4	11
Changes in valuation allowances	13	(74)	(104)
Net tax effect of intra-group items	(97)	(98)	(30)
Tax differentials of non-U.S. jurisdictions	(69)	(80)	(42)
Tax differentials of U.S. state taxes and local taxes	(6)	14	(2)
Impact of U.S. Tax Reform	(204)	0	0
Other items, net	(3)	10	(3)
Total benefit from income taxes	$ (100)	$ (96)	$ (33)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued expenses not currently deductible	$ 131	$ 286
Net operating losses	145	116
Capital loss carryforwards	28	28
Accrued retirement benefits	339	467
Deferred compensation	69	83
Stock options	24	36
Financial derivative transactions	18	12
Gross deferred tax assets	754	1,028
Less: valuation allowance	(162)	(134)
Net deferred tax assets	592	894
Deferred tax liabilities:
Cost of intangible assets, net of related amortization	929	1,431
Cost of tangible assets, net of related depreciation	56	73
Prepaid retirement benefits	114	85
Accrued revenue not currently taxable	62	119
Deferred tax liabilities	1,161	1,708
Net deferred tax liability	$ 569	$ 814

Income Taxes - Deferred Tax Lia

Income Taxes - Deferred Tax Liabilities, Balance Sheet Classification (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Other non-current assets	$ 46	$ 50
Deferred tax liabilities	615	864
Net deferred tax liability	$ 569	$ 814

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 134
Balance at end of year	162	$ 134
Valuation Allowance of Deferred Tax Assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	134	187	$ 280
Additions charged against/(credited to) to costs and expenses	35	0	0
Additions charged against/(credited to) to other accounts	0	21	2
Deductions	(7)	(74)	(95)
Balance at end of year	$ 162	$ 134	$ 187

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 56	$ 22	$ 19
Increases related to acquisitions	0	33	8
Increases related to tax positions in prior years	2	1	1
Decreases related to tax positions in prior years	(5)	(9)	(6)
Decreases related to settlements	0	(1)	0
Decreases related to lapse in statute of limitations	(2)	(1)	0
Increases related to current year tax positions	9	11	2
Cumulative translation adjustment and other adjustments	(1)	0	(2)
Balance at end of year	$ 59	$ 56	$ 22

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Information [Line Items]
Old federal corporate tax rate, percent	35.00%	35.00%	35.00%
Deferred tax assets, net of valuation allowance	$ 592,000,000	$ 894,000,000
Net operating losses	145,000,000	116,000,000
Valuation allowance	162,000,000	134,000,000
Changes in valuation allowances	13,000,000	(74,000,000)	$ (104,000,000)
Net deferred tax liability	569,000,000	814,000,000
Cumulative earnings	6,800,000,000
Unrecognized tax benefits	59,000,000	56,000,000	22,000,000	$ 19,000,000
Decrease in unrecognized tax benefits is reasonably possible	3,000,000	4,000,000	0
Interest on income taxes accrued	5,000,000	4,000,000
Income Tax Examination, Penalties Accrued	2,000,000
Non-State and Local
Tax Information [Line Items]
Net operating losses	289,000,000
Operating loss carryforwards, not subject to expiration	237,000,000
Foreign Tax Authority
Tax Information [Line Items]
Operating loss carryforwards, valuation allowance	34,000,000	28,000,000
State and Local
Tax Information [Line Items]
Changes in valuation allowances	28,000,000
Domestic Tax Authority
Tax Information [Line Items]
Operating loss carryforwards, valuation allowance	80,000,000	$ 78,000,000
Minimum
Tax Information [Line Items]
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	4,000,000
Maximum
Tax Information [Line Items]
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	6,000,000
Revenue Commissioners, Ireland | Domestic Tax Authority
Tax Information [Line Items]
Foreign statutory income tax rate		25.00%
Her Majesty's Revenue and Customs (HMRC) | Foreign Tax Authority | Capital Loss Carryforward
Tax Information [Line Items]
Tax credit carryforward	28,000,000	$ 28,000,000
United States
Tax Information [Line Items]
Release in valuation allowance		$ 69,000,000	$ (91,000,000)
United States | Non-State and Local | Tax Year 2018 Through 2037 [Member]
Tax Information [Line Items]
Operating loss carryforwards, subject to expiration	52,000,000
United States | State and Local | Tax Year 2018 Through 2037 [Member]
Tax Information [Line Items]
Operating loss carryforwards, subject to expiration	$ 1,500,000,000

Income Taxes - US Tax Reform (D

Income Taxes - US Tax Reform (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Cuts and Jobs Act [Line Items]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ (204)	$ 0	$ 0
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
U.S. federal taxes	$ 65	$ 35	$ 14
Current State and Local Tax Expense (Benefit)	7	14	$ 1
Taxes Payable, Current	90	$ 91
Tax Cuts and Jobs Act [Member]
Tax Cuts and Jobs Act [Line Items]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ (204)
New income tax rate	21.00%
Provisional decrease in net deferred tax liabilities	$ 208
Deferred income tax benefit, net	$ 208
U.S. corporate shareholders statutory deduction rate for dividends from 10 percent owned foreign corporations, percent	100.00%
Foreign withholding taxes and state income taxes on potential repatriation, amount previously deemed indefinitely reinvested	$ 1
Deferred tax expense (benefit) on expensing qualifying expenditures, provisional	(40)
Provisional increase in net deferred tax liabilities	14
Tax Cuts and Jobs Act [Member] | Maximum
Tax Cuts and Jobs Act [Line Items]
Potential repatriation, amount previously deemed indefinitely reinvested	$ 219
Income tax liability deduction re GILTI	50.00%
Net interest expense limit, percentage of adjusted taxable income	30.00%
One-Time Transition Tax [Member] | Tax Cuts and Jobs Act [Member]
Tax Cuts and Jobs Act [Line Items]
U.S. federal taxes	$ 70
Current State and Local Tax Expense (Benefit)	2
Deferred tax expense (benefit) on potential repatriation, amount previously deemed indefinitely reinvested	(76)
Taxes Payable, Current	6
Federal and state tax expense (benefit) on potential repatriation, amount previously deemed indefinitely reinvested	72
Domestic Tax Authority
Tax Cuts and Jobs Act [Line Items]
Provisional increase in current income taxes receivable, approximate	14
Section 162(m) [Member] | Executive Compensation [Member] | Tax Cuts and Jobs Act [Member]
Tax Cuts and Jobs Act [Line Items]
Other Tax Expense (Benefit)	8
Section 162(m) [Member] | Executive Compensation [Member] | Tax Cuts and Jobs Act [Member] | Maximum
Tax Cuts and Jobs Act [Line Items]
Compensation deduction limit	$ 1

Fixed Assets - Components of Fi

Fixed Assets - Components of Fixed Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Business Combination, Integration Related Costs	$ 269		$ 177	$ 84
Amortization	581		591	76
Analysis of fixed asset activity
Cost: at beginning of period	1,481		1,091
Additions	394		311
Acquisitions			204
Disposals	(82)		(36)
Foreign exchange	69		(89)
Cost: at end of period	1,862		1,481	1,091
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Depreciation: at beginning of period	(642)		(528)
Depreciation expense	(252)	[1]	(178)	(95)
Disposals	51		22
Foreign exchange	(34)		42
Depreciation: at end of period	(877)		(642)	(528)
Net book value	985		839
Furniture, equipment and software
Analysis of fixed asset activity
Cost: at beginning of period	1,009		724
Additions	303		265
Acquisitions			109
Disposals	(61)		(28)
Foreign exchange	49		(61)
Cost: at end of period	1,300		1,009	724
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Depreciation: at beginning of period	(464)		(393)
Depreciation expense	(199)		(119)
Disposals	37		17
Foreign exchange	(26)		31
Depreciation: at end of period	(652)		(464)	(393)
Net book value	648		545
Leasehold improvements
Analysis of fixed asset activity
Cost: at beginning of period	382		272
Additions	91		44
Acquisitions			95
Disposals	(21)		(8)
Foreign exchange	16		(21)
Cost: at end of period	468		382	272
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Depreciation: at beginning of period	(137)		(94)
Depreciation expense	(47)		(55)
Disposals	14		5
Foreign exchange	(6)		7
Depreciation: at end of period	(176)		(137)	(94)
Net book value	292		245
Land and buildings
Analysis of fixed asset activity
Cost: at beginning of period	90		95
Additions	0		2
Acquisitions			0
Disposals	0		0
Foreign exchange	4		(7)
Cost: at end of period	94		90	95
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Depreciation: at beginning of period	(41)		(41)
Depreciation expense	(6)		(4)
Disposals	0		0
Foreign exchange	(2)		4
Depreciation: at end of period	(49)		(41)	$ (41)
Net book value	45		$ 49
Depreciation [Member]
Property, Plant and Equipment [Line Items]
Business Combination, Integration Related Costs	$ 49
[1]	Depreciation expense included here does not equal the depreciation expense on the statement of comprehensive income for the year ended December 31, 2017 due to the inclusion of $49 million which has been classified as transaction and integration expenses.

Fixed Assets - Assets Held Unde

Fixed Assets - Assets Held Under Capital Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Capital leases	$ 31	$ 32
Accumulated depreciation	(14)	(12)
Net book value	17	20
Capital Leases
Property, Plant and Equipment [Line Items]
Depreciation	$ 2	$ 2	$ 2

Goodwill and Other Intangible82

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 04, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization	$ 581	$ 591	$ 76
Acquired unfavorable lease liabilities	$ 26	29
Weighted average remaining life of amortizable intangible assets	14 years 4 months
In Process Research and Development
Finite-Lived Intangible Assets [Line Items]
Intangible asset		$ 36		$ 39

Goodwill and Other Intangible83

Goodwill and Other Intangible Assets - Components of Goodwill (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, gross, beginning balance		$ 11,011	$ 10,905		$ 4,229
Accumulated impairment losses, beginning balance		(492)	(492)
Goodwill, net, beginning balance		10,413	3,737
Purchase price allocation adjustments			6
Goodwill reassigned in segment realignment (ii)		0
Goodwill acquired during the period		8	6,785
Goodwill disposed of during the period		(63)	(5)
Foreign exchange		161	(110)
Goodwill, gross, ending balance		11,011	10,905
Accumulated impairment losses, ending balance		(492)	(492)
Goodwill, net, ending balance		10,519	10,413
HCB
Goodwill [Roll Forward]
Goodwill, gross, beginning balance		4,342	4,412		986
Accumulated impairment losses, beginning balance		(130)	(130)
Goodwill, net, beginning balance		4,282	856
Purchase price allocation adjustments			8
Goodwill reassigned in segment realignment (ii)	[1]	(113)
Goodwill acquired during the period		0	3,458	[2]
Goodwill disposed of during the period		(31)	0
Foreign exchange		74	(40)
Goodwill, gross, ending balance		4,342	4,412
Accumulated impairment losses, ending balance		(130)	(130)
Goodwill, net, ending balance		4,212	4,282
CRB
Goodwill [Roll Forward]
Goodwill, gross, beginning balance		2,261	2,178		2,212
Accumulated impairment losses, beginning balance		(362)	(362)
Goodwill, net, beginning balance		1,816	1,850
Purchase price allocation adjustments			5
Goodwill reassigned in segment realignment (ii)	[1]	13
Goodwill acquired during the period		8	0
Goodwill disposed of during the period		(5)	(5)
Foreign exchange		67	(34)
Goodwill, gross, ending balance		2,261	2,178
Accumulated impairment losses, ending balance		(362)	(362)
Goodwill, net, ending balance		1,899	1,816
IRR
Goodwill [Roll Forward]
Goodwill, gross, beginning balance		1,851	1,758		1,031
Accumulated impairment losses, beginning balance		0	0
Goodwill, net, beginning balance		1,758	1,031
Purchase price allocation adjustments			(7)
Goodwill reassigned in segment realignment (ii)	[1]	100
Goodwill acquired during the period		0	770
Goodwill disposed of during the period		(27)	0
Foreign exchange		20	(36)
Goodwill, gross, ending balance		1,851	1,758
Accumulated impairment losses, ending balance		0	0
Goodwill, net, ending balance		1,851	1,758
Benefits Delivery and Administration [Member]
Goodwill [Roll Forward]
Goodwill, gross, beginning balance		2,557	2,557		$ 0
Accumulated impairment losses, beginning balance		0	0
Goodwill, net, beginning balance		2,557	0
Purchase price allocation adjustments			0
Goodwill reassigned in segment realignment (ii)		0
Goodwill acquired during the period		0	2,557
Goodwill disposed of during the period		0	0
Foreign exchange		0	0
Goodwill, gross, ending balance		2,557	2,557
Accumulated impairment losses, ending balance		0	0
Goodwill, net, ending balance		$ 2,557	$ 2,557
[1]	Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2017. See Note 4 — Segment Information for further information.
[2]	Goodwill acquired consists primarily of goodwill recognized from the Merger.

Goodwill and Other Intangible84

Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets and Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015	Jan. 04, 2016
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		$ 4,332		$ 1,115
Purchase price allocation adjustments				(10)
Intangible assets acquired		50		3,953
Intangible assets disposed		(45)		(5)
Amortization		(581)		(591)		$ (76)
Amortization		(583)		(593)
Foreign Exchange		128		(128)
Balance as of end of period		3,882		4,332		1,115
Gross Carrying Amount		5,408		5,275
Accumulated Amortization		(1,526)		(943)
Unfavorable agreements, Gross Carrying Amount		34		34
Unfavorable agreements, Accumulated Amortization		8		5
Client relationships
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		2,655		920
Purchase price allocation adjustments				2
Intangible assets acquired		13		2,222
Intangible assets disposed		(44)		(5)
Amortization				(395)
Amortization		(379)
Foreign Exchange		97		(89)
Balance as of end of period		2,342		2,655		920
Gross Carrying Amount		3,462		3,396
Accumulated Amortization		(1,120)		(741)
Management contracts
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		54		62
Purchase price allocation adjustments				0
Intangible assets acquired		0		0
Intangible assets disposed		0		0
Amortization				(4)
Amortization		(4)
Foreign Exchange		6		(4)
Balance as of end of period		56		54		62
Gross Carrying Amount		68		62
Accumulated Amortization		(12)		(8)
Software
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		570		77
Purchase price allocation adjustments				(13)
Intangible assets acquired		36	[1]	675	[2]
Intangible assets disposed		0		0
Amortization				(142)
Amortization		(150)
Foreign Exchange		17		(27)
Balance as of end of period		473		570		77
Gross Carrying Amount		764		711
Accumulated Amortization		(291)		(141)
Trademark and trade name
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		1,006		50
Purchase price allocation adjustments				1
Intangible assets acquired		0		1,003
Intangible assets disposed		(1)		0
Amortization				(45)
Amortization		(44)
Foreign Exchange		5		(3)
Balance as of end of period		966		1,006		50
Gross Carrying Amount		1,055		1,051
Accumulated Amortization		(89)		(45)
Product
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		33		0
Purchase price allocation adjustments				0
Intangible assets acquired		0		42
Intangible assets disposed		0		0
Amortization		(3)		(3)
Foreign Exchange		3		(6)
Balance as of end of period		33		33		0
Gross Carrying Amount		39		36
Accumulated Amortization		(6)		(3)
Favorable agreements
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		11		2
Purchase price allocation adjustments				0
Intangible assets acquired		1		11
Intangible assets disposed		0		0
Amortization	[3]			(2)
Amortization	[3]	(2)
Foreign Exchange		0		0
Balance as of end of period		10		11		2
Gross Carrying Amount		14		13
Accumulated Amortization		(4)		(2)
Other
Finite-lived Intangible Assets [Roll Forward]
Balance as of beginning of period		3		4
Purchase price allocation adjustments				0
Intangible assets acquired		0		0
Intangible assets disposed		0		0
Amortization				(2)
Amortization		(1)
Foreign Exchange		0		1
Balance as of end of period		2		3		$ 4
Gross Carrying Amount		6		6
Accumulated Amortization		(4)		(3)
Unfavorable agreements
Finite-lived Intangible Assets [Roll Forward]
Unfavorable agreements, Gross Carrying Amount		34		34
Unfavorable agreements, Accumulated Amortization		$ 8		5
In Process Research and Development
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)				$ 36			$ 39
[1]	All in-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ($36 million at the date placed into service due to changes in foreign currency exchange rates) have been placed into service during the year ended December 31, 2017 and have been included as intangible assets acquired in this presentation.
[2]	In-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ($36 million at December 31, 2016) had not yet been placed in service and are not included in this presentation.
[3]	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.

Goodwill and Other Intangible85

Goodwill and Other Intangible Assets - Schedule of Future Amortization Expense and Rent Offset (Details) $ in Millions	Dec. 31, 2017USD ($)
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2,018	$ 535
2,019	479
2,020	426
2,021	348
2,022	289
Thereafter	1,795
Total	3,872
Rent offset
2,018	(4)
2,019	(2)
2,020	(3)
2,021	(2)
2,022	(2)
Thereafter	(3)
Total	$ (16)

Derivative Financial Instrume86

Derivative Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative, loss on derivative within the next twelve months	$ 26,000,000
Not Designated as Hedging Instrument | Forward exchange contracts
Derivative [Line Items]
Derivative, notional amount	971,000,000	$ 630,000,000
Derivative asset, fair value	3,000,000
Derivative liability, fair value		8,000,000
Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Derivative, notional amount	300,000,000	300,000,000
Derivative liability, fair value	1,000,000	0
Cash Flow Hedges | Designated as Hedging Instrument | Forward exchange contracts
Derivative [Line Items]
Derivative, notional amount	937,000,000	945,000,000
Derivative liability, fair value	21,000,000	110,000,000
Gain/(loss) recognized in OCI (effective portion)	39,000,000	(127,000,000)	$ (38,000,000)
(Loss)/gain reclassified from OCI into income (effective portion)	(53,000,000)	(42,000,000)	4,000,000
(Loss)/gain recognized in income (ineffective portion and amount excluded from effectiveness testing)	$ (1,000,000)	(1,000,000)	1,000,000
Maximum
Derivative [Line Items]
Longest outstanding maturity	2 years 11 months
Other Expense [Member] | Not Designated as Hedging Instrument | Forward exchange contracts
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 11,000,000	$ (3,000,000)	$ (3,000,000)

Debt - Schedule of Short-term D

Debt - Schedule of Short-term Debt and Current Maturities of Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016	Mar. 15, 2016
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	$ 85		$ 508
Term Loan | 7-year term loan facility
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	0		22
Term Loan | Term loan due 2019
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	$ 85		85
7-year term loan facility | 7-year term loan facility
Short-term Debt [Line Items]
Term loan period	7 years
Senior Notes | 4.125% senior notes due 2016
Short-term Debt [Line Items]
Stated interest rate (as a percent)	4.125%			4.125%
Senior Notes | 6.200% senior notes due 2017
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	$ 0		394
Stated interest rate (as a percent)	6.20%	6.20%
Bank Overdrafts
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	$ 0		5
Other (i)
Short-term Debt [Line Items]
Short-term debt and current portion of the long-term debt	$ 0		$ 2

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt (Details)		Jan. 04, 2016USD ($)	Mar. 28, 2007USD ($)	Dec. 31, 2017USD ($)	Mar. 07, 2017USD ($)	Dec. 31, 2016USD ($)	May 26, 2016USD ($)	May 26, 2016EUR (€)	Mar. 22, 2016USD ($)	Aug. 31, 2013	Aug. 15, 2013USD ($)	Mar. 11, 2011USD ($)	Sep. 30, 2009USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 5,638,000,000
Long-term Debt, Excluding Current Maturities				4,450,000,000		$ 3,357,000,000
Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt				884,000,000
Maximum borrowing capacity				1,250,000,000	$ 1,250,000,000
Long-term Debt, Excluding Current Maturities						0
Line of Credit | Revolving Credit Facility | Revolving $800 million credit facility
Debt Instrument [Line Items]
Long-term debt				884,000,000
Maximum borrowing capacity				800,000,000	$ 800,000,000
Long-term Debt, Excluding Current Maturities				0		238,000,000
Notes Payable
Debt Instrument [Line Items]
Long-term debt				$ 170,000,000
Notes Payable | 7-year term loan facility
Debt Instrument [Line Items]
Term loan period				7 years
Long-term Debt, Excluding Current Maturities				$ 0		196,000,000
Notes Payable | Term loan due 2019
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 340,000,000
Term loan period		4 years
Long-term Debt, Excluding Current Maturities				84,000,000		169,000,000
Senior Notes
Debt Instrument [Line Items]
Long-term debt				$ 3,506,000,000
Senior Notes | 6.200% senior notes due 2017
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 600,000,000
Term loan period			10 years
Stated interest rate (as a percent)			6.20%	6.20%						6.20%
Senior Notes | 7.000% senior notes due 2019
Debt Instrument [Line Items]
Debt Instrument, Face Amount													$ 300,000,000
Stated interest rate (as a percent)				7.00%						7.00%			7.00%
Long-term Debt, Excluding Current Maturities				$ 186,000,000		186,000,000
Senior Notes | 5.750% senior notes due 2021
Debt Instrument [Line Items]
Debt Instrument, Face Amount												$ 500,000,000
Stated interest rate (as a percent)				5.75%								5.75%
Long-term Debt, Excluding Current Maturities				$ 497,000,000		496,000,000
Senior Notes | 3.500% senior notes due 2021
Debt Instrument [Line Items]
Debt Instrument, Face Amount									$ 450,000,000
Stated interest rate (as a percent)				3.50%					3.50%
Long-term Debt, Excluding Current Maturities				$ 447,000,000		446,000,000
Senior Notes | 2.125% senior notes due 2022 (i)
Debt Instrument [Line Items]
Stated interest rate (as a percent)				2.125%			2.125%	2.125%
Long-term Debt, Excluding Current Maturities	[1]			$ 644,000,000		565,000,000
Senior Notes | 4.625% senior notes due 2023
Debt Instrument [Line Items]
Debt Instrument, Face Amount											$ 250,000,000
Stated interest rate (as a percent)				4.625%							4.625%
Long-term Debt, Excluding Current Maturities				$ 248,000,000		247,000,000
Senior Notes | 3.600% senior notes due 2024
Debt Instrument [Line Items]
Stated interest rate (as a percent)				3.60%
Long-term Debt, Excluding Current Maturities				$ 645,000,000		0
Senior Notes | 4.400% senior notes due 2026
Debt Instrument [Line Items]
Debt Instrument, Face Amount									$ 550,000,000
Stated interest rate (as a percent)				4.40%					4.40%
Long-term Debt, Excluding Current Maturities				$ 544,000,000		543,000,000
Senior Notes | 6.125% senior notes due 2043
Debt Instrument [Line Items]
Debt Instrument, Face Amount											$ 275,000,000
Stated interest rate (as a percent)				6.125%							6.125%
Long-term Debt, Excluding Current Maturities				$ 271,000,000		$ 271,000,000
Trinity Acquisition plc | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 609,000,000	€ 540,000,000	$ 1,000,000,000		$ 525,000,000
Long-term debt				$ 2,100,000,000
Trinity Acquisition plc | Senior Notes | 2.125% senior notes due 2022 (i)
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 609,000,000	€ 540,000,000
[1]	Notes issued in Euro (€540 million)

Debt - Narrative (Details)

Debt - Narrative (Details)

May 16, 2017USD ($)

Mar. 28, 2017USD ($)

Mar. 07, 2017USD ($)

May 26, 2016USD ($)

May 26, 2016EUR (€)

Mar. 22, 2016USD ($)

Jan. 04, 2016USD ($)

Dec. 29, 2015

Dec. 28, 2015USD ($)

Dec. 19, 2015USD ($)

Dec. 19, 2015EUR (€)

Nov. 20, 2015EUR (€)tranche

Mar. 28, 2007USD ($)

Aug. 31, 2013USD ($)

Mar. 07, 2017USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Jun. 30, 2017

Apr. 28, 2017USD ($)

Mar. 07, 2017EUR (€)

May 26, 2016EUR (€)

Mar. 15, 2016

Dec. 31, 2015USD ($)

Aug. 15, 2013USD ($)

Mar. 11, 2011USD ($)

Sep. 30, 2009USD ($)

Debt Instrument [Line Items]

Debt Instrument, Covenant Compliance

in compliance

in compliance

Senior Notes | 4.125% Senior Notes Due 2016

Debt Instrument [Line Items]

Stated interest rate (as a percent)

4.125%

4.125%

Senior Notes | 6.200% senior notes due 2017

Debt Instrument [Line Items]

Stated interest rate (as a percent)

6.20%

6.20%

Line of Credit | Term Loan Facility | 1-year Term Loan Facility Matures 2016

Debt Instrument [Line Items]

Term loan period

1 year

Line of Credit | Notes Payable | 1-year Term Loan Facility Matures 2016

Debt Instrument [Line Items]

Term loan period

1 year

1 year

Number of tranches | tranche

2

Short-term borrowings outstanding

$ 592,000,000

Debt issuance fees

$ 5,000,000

Line of Credit | Notes Payable | 1-year Term Loan Facility Matures 2016, Tranche one

Debt Instrument [Line Items]

Term loan period

1 year

1 year

Maximum borrowing capacity | €

€ 550,000,000

Amounts drawn on line of credit

$ 592,000,000

€ 544,000,000

Line of Credit | Notes Payable | 1-year Term Loan Facility Matures 2016, Tranche two

Debt Instrument [Line Items]

Repayment of line of credit

$ 400,000,000

Amounts drawn on line of credit

$ 400,000,000

Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member]

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 1,250,000,000

$ 1,250,000,000

$ 1,250,000,000

Long-term borrowings outstanding

$ 409,000,000

409,000,000

€ 45,000,000

Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member] | LIBOR | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.00%

Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member] | LIBOR | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.75%

Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member] | Bank Base Rate | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

0.00%

Line of Credit | Revolving Credit Facility | Revolving 1.25 Billion Dollar Credit Facility [Member] | Bank Base Rate | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

0.75%

Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility

Debt Instrument [Line Items]

Current borrowing capacity

$ 800,000,000

800,000,000

Repayment of line of credit

300,000,000

Maximum borrowing capacity

$ 800,000,000

$ 800,000,000

800,000,000

Long-term borrowings outstanding

$ 238,000,000

Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility | LIBOR | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.25%

Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility | LIBOR | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

2.00%

Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility | Bank Base Rate | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

0.25%

Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility | Bank Base Rate | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.00%

Line of Credit | Revolving Credit Facility | WSI Revolving Credit Facility

Debt Instrument [Line Items]

Long-term borrowings outstanding

$ 0

$ 0

$ 400,000,000

Notes Payable | 7-year term loan facility

Debt Instrument [Line Items]

Term loan period

7 years

Quarterly payment

$ 6,000,000

Final payment of debt

186,000,000

Notes Payable | Term loan due 2019

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 340,000,000

Proceeds from long-term debt issuance

$ 340,000,000

Term loan period

4 years

Quarterly payment

21,000,000

Debt issuance fees

$ 1,000,000

Weighted average interest rate (as a percent)

2.33%

Long-term debt, gross

$ 170,000,000

Notes Payable | Term loan due 2019 | LIBOR | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.25%

Notes Payable | Term loan due 2019 | LIBOR | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.75%

Notes Payable | Term loan due 2019 | Bank Base Rate | Minimum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

0.25%

Notes Payable | Term loan due 2019 | Bank Base Rate | Maximum

Debt Instrument [Line Items]

Interest rate spread (as a percent)

0.75%

Senior Notes | 2.125% senior notes due 2022 (i)

Debt Instrument [Line Items]

Stated interest rate (as a percent)

2.125%

2.125%

2.125%

Effective interest rate (as a percent)

2.154%

Proceeds from long-term debt issuance

$ 600,000,000

€ 535,000,000

Senior Notes | Senior Notes Due 2021 and 2026

Debt Instrument [Line Items]

Proceeds from long-term debt issuance

988,000,000

Senior Notes | 3.500% senior notes due 2021

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 450,000,000

Stated interest rate (as a percent)

3.50%

3.50%

Effective interest rate (as a percent)

3.707%

Senior Notes | 4.400% senior notes due 2026

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 550,000,000

Stated interest rate (as a percent)

4.40%

4.40%

Effective interest rate (as a percent)

4.572%

Senior Notes | 4.125% Senior Notes Due 2016

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 300,000,000

Stated interest rate (as a percent)

4.125%

Effective interest rate (as a percent)

4.24%

Senior Notes | 4.625% senior notes due 2023

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 250,000,000

Stated interest rate (as a percent)

4.625%

4.625%

Effective interest rate (as a percent)

4.696%

Senior Notes | 6.125% senior notes due 2043

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 275,000,000

Stated interest rate (as a percent)

6.125%

6.125%

Effective interest rate (as a percent)

6.154%

Senior Notes | 5.750% senior notes due 2021

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 500,000,000

Stated interest rate (as a percent)

5.75%

5.75%

Effective interest rate (as a percent)

5.871%

Senior Notes | 7.000% senior notes due 2019

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 300,000,000

Stated interest rate (as a percent)

7.00%

7.00%

7.00%

Effective interest rate (as a percent)

7.081%

Repayments of debt

$ 113,000,000

Senior Notes | 6.200% senior notes due 2017

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 600,000,000

Stated interest rate (as a percent)

6.20%

6.20%

6.20%

Effective interest rate (as a percent)

6.253%

Term loan period

10 years

Repayments of debt

$ 407,000,000

$ 206,000,000

Senior Notes | 3.600% senior notes due 2024 [Member]

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 650,000,000

Stated interest rate (as a percent)

3.60%

Effective interest rate (as a percent)

3.614%

Proceeds from Debt, Net of Issuance Costs

$ 644,000,000

BBB | Baa3 | Line of Credit | Revolving Credit Facility | Revolving $800 million Credit Facility | LIBOR

Debt Instrument [Line Items]

Interest rate spread (as a percent)

1.375%

BBB | Baa3 | Line of Credit | Revolving Credit Facility | WSI Revolving Credit Facility | LIBOR

Debt Instrument [Line Items]

Debt Instrument, Credit Rating

BBB/Baa3

Trinity Acquisition plc [Member] | Senior Notes

Debt Instrument [Line Items]

Debt Instrument, Face Amount

609,000,000

$ 1,000,000,000

€ 540,000,000

$ 525,000,000

Trinity Acquisition plc [Member] | Senior Notes | 2.125% senior notes due 2022 (i)

Debt Instrument [Line Items]

Debt Instrument, Face Amount

$ 609,000,000

€ 540,000,000

Debt - Maturities Of Long Term

Debt - Maturities Of Long Term Debt (Details) $ in Millions	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
2,017	$ 232
2,018	416
2,019	134
2,020	1,057
2,021	1,610
Thereafter	2,189
Total	5,638
Senior Notes
Debt Instrument [Line Items]
2,017	0
2,018	187
2,019	0
2,020	950
2,021	644
Thereafter	1,725
Total	3,506
Senior Notes | Interest on Senior Notes
Debt Instrument [Line Items]
2,017	147
2,018	144
2,019	134
2,020	107
2,021	82
Thereafter	464
Total	1,078
Term Loan
Debt Instrument [Line Items]
2,017	85
2,018	85
2,019	0
2,020	0
2,021	0
Thereafter	0
Total	170
Revolving Credit Facility | Line of Credit | Revolving $800 million credit facility
Debt Instrument [Line Items]
2,017	0
2,018	0
2,019	0
2,020	0
2,021	884
Thereafter	0
Total	$ 884

Debt - Interest Expense (Detail

Debt - Interest Expense (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Interest expense		$ 188	$ 184	$ 142
Senior Notes
Debt Instrument [Line Items]
Interest expense		148	139	114
Term Loan
Debt Instrument [Line Items]
Interest expense		8	17	5
Other (i)
Debt Instrument [Line Items]
Interest expense	[1]	14	16	15
Revolving Credit Facility | Line of Credit | Revolving $800 million credit facility
Debt Instrument [Line Items]
Interest expense		17	10	6
Revolving Credit Facility | Line of Credit | WSI Revolving Credit Facility
Debt Instrument [Line Items]
Interest expense		$ 1	$ 2	$ 2
[1]	(i)Other primarily includes debt issuance costs, interest expense on capitalized leases and accretion on deferred and contingent consideration

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds / exchange traded funds		$ 40	$ 37
Derivative financial instruments, assets	[1]	18	15
Contingent consideration	[2]	51	55
Derivative financial instruments, liabilities	[1]	37	133
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds / exchange traded funds		40	37
Derivative financial instruments, assets	[1]	0	0
Contingent consideration		0	0
Derivative financial instruments, liabilities	[1]	0	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds / exchange traded funds		0	0
Derivative financial instruments, assets	[1]	18	15
Contingent consideration		0	0
Derivative financial instruments, liabilities	[1]	37	133
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds / exchange traded funds		0	0
Derivative financial instruments, assets	[1]	0	0
Contingent consideration	[2]	51	55
Derivative financial instruments, liabilities	[1]	$ 0	$ 0
Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average discount rate on material contingent consideration calculation		9.64%	10.76%
[1]	See Note 9 — Derivative Financial Instruments for further information on our derivative instruments.
[2]	Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The weighted-average discount rate used on our material contingent consideration calculations was 9.64% and 10.76% at December 31, 2017 and December 31, 2016, respectively. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable.

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Liabilities Measured Using Significant Unobservable Inputs Level 3 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of beginning of period	$ 55
Obligations assumed	0
Sales	(7)
Payments	(10)
Realized and unrealized gains	9
Foreign exchange	4
Balance as of end of period	$ 51

Fair Value Measurements - Sch94

Fair Value Measurements - Schedule of Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt and current portion of long-term debt	$ 85	$ 508
Long-term debt	4,450	3,357
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt and current portion of long-term debt	85	513
Long-term debt	$ 4,706	$ 3,504

Retirement Benefits - Narrative

Retirement Benefits - Narrative (Details) $ in Millions	Jan. 04, 2016USD ($)	Mar. 06, 2015USD ($)	Dec. 31, 2017	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Pension settlement and curtailment losses, net				$ 36	$ 0	$ 0
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)				99.00%
Towers Watson & Co.
Defined Benefit Plan Disclosure [Line Items]
Plan assets acquired	$ 3,700
Benefit obligation acquired	4,600
Pension assets	67
Liability for pension benefits	$ (923)
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Plan assets acquired				$ 0	2,453
Benefit obligation acquired				0	3,012
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Plan assets acquired				0	906
Benefit obligation acquired				0	842
Plan amendments		$ (215)
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets acquired				0	321
Benefit obligation acquired				0	530
PRW
Defined Benefit Plan Disclosure [Line Items]
Plan assets acquired				0	4
Benefit obligation acquired				$ 0	112
Average remaining service period				9 years 11 months
Defined Contributions Plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan expenses				$ 154	152	$ 77
Defined Contributions Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Vesting period				2 years
Change in Assumptions for Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Credit to net periodic benefit income					$ 51
Defined Contribution Plan Tranche One | Defined Contributions Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match				100.00%
Maximum annual contributions per employee, percent				1.00%
Defined Contribution Plan Tranche Two | Defined Contributions Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match				50.00%
Maximum annual contributions per employee, percent				5.00%
Newly-eligible employees [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan required employee contribution rate			0.02

Retirement Benefits - Change in

Retirement Benefits - Change in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	Mar. 06, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Plan Assets
Fair value of plan assets, beginning of year		$ 8,109
Fair value of plan assets, end of year		9,128	$ 8,109
Pension benefits assets		764	488
Non-current liability for pension benefits		(1,259)	(1,321)
Pension Plans | UNITED STATES
Change in Benefit Obligation
Benefit obligation, beginning of year		4,169	976
Service cost		66	59	$ 0
Interest cost		139	137	41
Employee contributions		6	0
Actuarial losses		293	151
Settlements		(16)	0
Benefits paid		(181)	(166)
Business combinations		0	3,012
Transfers in		0	0
Foreign currency changes		0	0
Benefit obligation, end of year		4,476	4,169	976
Change in Plan Assets
Fair value of plan assets, beginning of year		3,280	749
Actual return on plan assets		464	153
Employer contributions		101	91
Employee contributions		6	0
Settlements		(16)	0
Benefits paid		(181)	(166)
Business combinations		0	2,453
Transfers in		0	0
Foreign currency adjustment		0	0
Fair value of plan assets, end of year		3,654	3,280	749
Funded status at end of year		(822)	(889)
Accumulated Benefit Obligation		4,476	4,169
Pension benefits assets		0	0
Current liability for pension benefits		(40)	(47)
Non-current liability for pension benefits		(782)	(842)
Components on the Consolidated Balance Sheet		(822)	(889)
Pension Plans | United Kingdom
Change in Benefit Obligation
Benefit obligation, beginning of year		3,899	2,881
Service cost		32	24	33
Interest cost		93	114	107
Employee contributions		1	1
Actuarial losses		2	852
Settlements		(138)	(12)
Benefits paid		(93)	(130)
Business combinations		0	842
Transfers in		0	0
Foreign currency changes		369	(673)
Plan amendments	$ (215)
Benefit obligation, end of year		4,165	3,899	2,881
Change in Plan Assets
Fair value of plan assets, beginning of year		4,360	3,478
Actual return on plan assets		290	782
Employer contributions		66	106
Employee contributions		1	1
Settlements		(138)	(12)
Benefits paid		(93)	(130)
Business combinations		0	906
Transfers in		0	0
Foreign currency adjustment		424	(771)
Fair value of plan assets, end of year		4,910	4,360	3,478
Funded status at end of year		745	461
Accumulated Benefit Obligation		4,165	3,899
Pension benefits assets		754	478
Current liability for pension benefits		0	0
Non-current liability for pension benefits		(9)	(17)
Components on the Consolidated Balance Sheet		745	461
Pension Plans | Other Foreign Plans [Member]
Change in Benefit Obligation
Benefit obligation, beginning of year		732	184
Service cost		20	19	3
Interest cost		17	18	3
Employee contributions		0	0
Actuarial losses		5	61
Settlements		(1)	(61)
Benefits paid		(29)	(24)
Business combinations		0	530
Transfers in		1	1
Foreign currency changes		77	4
Benefit obligation, end of year		822	732	184
Change in Plan Assets
Fair value of plan assets, beginning of year		467	158
Actual return on plan assets		42	26
Employer contributions		34	39
Employee contributions		0	0
Settlements		(1)	(58)
Benefits paid		(29)	(24)
Business combinations		0	321
Transfers in		1	1
Foreign currency adjustment		48	4
Fair value of plan assets, end of year		562	467	158
Funded status at end of year		(260)	(265)
Accumulated Benefit Obligation		790	696
Pension benefits assets		17	10
Current liability for pension benefits		(6)	(7)
Non-current liability for pension benefits		(271)	(268)
Components on the Consolidated Balance Sheet		(260)	(265)
PRW
Change in Benefit Obligation
Benefit obligation, beginning of year		113	0
Service cost		0	1	0
Interest cost		4	3	0
Employee contributions		6	7
Actuarial losses		14	4
Settlements		0	0
Benefits paid		(14)	(14)
Business combinations		0	112
Transfers in		0	0
Foreign currency changes		0	0
Benefit obligation, end of year		123	113	0
Change in Plan Assets
Fair value of plan assets, beginning of year		4	0
Actual return on plan assets		0	0
Employer contributions		6	7
Employee contributions		6	7
Settlements		0	0
Benefits paid		(14)	(14)
Business combinations		0	4
Transfers in		0	0
Foreign currency adjustment		0	0
Fair value of plan assets, end of year		2	4	$ 0
Funded status at end of year		(121)	(109)
Accumulated Benefit Obligation		123	113
Pension benefits assets		0	0
Current liability for pension benefits		(5)	(3)
Non-current liability for pension benefits		(116)	(106)
Components on the Consolidated Balance Sheet		$ (121)	$ (109)

Retirement Benefits - Amounts R

Retirement Benefits - Amounts Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 663	$ 603
Net prior service gain	0	0
Accumulated other comprehensive loss	663	603
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	909	918
Net prior service gain	(142)	(147)
Accumulated other comprehensive loss	767	771
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	79	80
Net prior service gain	0	0
Accumulated other comprehensive loss	79	80
PRW
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	19	4
Net prior service gain	0	0
Accumulated other comprehensive loss	$ 19	$ 4

Retirement Benefits - Benefit O

Retirement Benefits - Benefit Obligation In Excess Of Plan Assets (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 4,476	$ 4,169
Fair value of plan assets	3,654	3,280
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	10	843
Fair value of plan assets	0	825
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	758	686
Fair value of plan assets	$ 481	$ 411

Retirement Benefits - Accumulat

Retirement Benefits - Accumulated Benefit Obligation In Excess of Plan Assets (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 4,476	$ 4,169
Accumulated benefit obligation at end of year	4,476	4,169
Fair value of plan assets	3,654	3,280
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	10	843
Accumulated benefit obligation at end of year	10	843
Fair value of plan assets	0	825
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	758	686
Accumulated benefit obligation at end of year	726	650
Fair value of plan assets	$ 481	$ 411

Retirement Benefits - Net Perio

Retirement Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 66	$ 59	$ 0
Interest cost	139	137	41
Expected return on plan assets	(245)	(240)	(57)
Amortization of unrecognized prior service credit	0	0	0
Amortization of net loss/(gain)	13	12	11
Settlement	1	0	0
Curtailment gain	0	0	0
Net periodic benefit (income)/cost	(26)	(32)	(5)
Net actuarial loss/(gain)	74	238	(16)
Amortization of unrecognized actuarial loss	(13)	(12)	(11)
Prior service gain	0	0	0
Amortization of unrecognized prior service credit	0	0	0
Settlement	(1)	0	0
Curtailment loss	0	0	0
Total recognized in other comprehensive loss/(income)	60	226	(27)
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	34	194	(32)
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Service cost	32	24	33
Interest cost	93	114	107
Expected return on plan assets	(284)	(253)	(230)
Amortization of unrecognized prior service credit	(18)	(19)	(18)
Amortization of net loss/(gain)	53	42	36
Settlement	37	0	0
Curtailment gain	0	0	(5)
Net periodic benefit (income)/cost	(87)	(92)	(77)
Net actuarial loss/(gain)	(4)	323	59
Amortization of unrecognized actuarial loss	(53)	(42)	(36)
Prior service gain	0	0	(215)
Amortization of unrecognized prior service credit	18	19	18
Settlement	(37)	0	0
Curtailment loss	0	0	18
Total recognized in other comprehensive loss/(income)	(76)	300	(156)
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	(163)	208	(233)
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	20	19	3
Interest cost	17	18	3
Expected return on plan assets	(30)	(27)	(3)
Amortization of unrecognized prior service credit	0	0	0
Amortization of net loss/(gain)	2	0	1
Settlement	1	5	0
Curtailment gain	0	0	0
Net periodic benefit (income)/cost	10	15	4
Net actuarial loss/(gain)	(7)	62	(5)
Amortization of unrecognized actuarial loss	(2)	0	(1)
Prior service gain	0	0	0
Amortization of unrecognized prior service credit	0	0	0
Settlement	(1)	(8)	0
Curtailment loss	0	0	0
Total recognized in other comprehensive loss/(income)	(10)	54	(6)
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	0	69	(2)
PRW
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0
Interest cost	4	3	0
Expected return on plan assets	0	0	0
Amortization of unrecognized prior service credit	0	0	0
Amortization of net loss/(gain)	0	0	0
Settlement	0	0	0
Curtailment gain	0	0	0
Net periodic benefit (income)/cost	4	4	0
Net actuarial loss/(gain)	14	4	0
Amortization of unrecognized actuarial loss	0	0	0
Prior service gain	0	0	0
Amortization of unrecognized prior service credit	0	0	0
Settlement	0	0	0
Curtailment loss	0	0	0
Total recognized in other comprehensive loss/(income)	14	4	0
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	$ 18	$ 8	$ 0

Retirement Benefits - Amounts i

Retirement Benefits - Amounts in AOCI to be Recognized Next Fiscal Year (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	$ 11
Prior service gain	0
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	47
Prior service gain	(19)
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	2
Prior service gain	0
PRW
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	1
Prior service gain	$ 0

Retirement Benefits - Assumptio

Retirement Benefits - Assumptions Used (Details)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]			3.90%
Discount rate - PBO		4.00%	4.20%
Discount rate - service cost		3.90%	3.90%
Discount rate - interest cost on service cost		3.20%	3.20%
Discount rate - interest cost on PBO		3.40%	3.40%
Expected long-term rate of return on assets		7.60%	7.60%	7.30%
Rate of increase in compensation levels		4.30%	4.30%
Discount rate		3.60%	4.00%
Rate of increase in compensation levels		4.30%	4.30%
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]			3.60%
Discount rate - PBO		2.60%	3.80%
Discount rate - service cost		2.60%	3.80%
Discount rate - interest cost on service cost		2.40%	3.80%
Discount rate - interest cost on PBO		2.30%	3.40%
Expected long-term rate of return on assets		6.30%	6.20%	6.50%
Rate of increase in compensation levels		3.20%	3.20%	2.90%
Discount rate		2.60%	2.60%
Rate of increase in compensation levels		3.00%	3.20%
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]			2.30%
Discount rate - PBO		2.70%	3.20%
Discount rate - service cost		3.00%	3.40%
Discount rate - interest cost on service cost		2.80%	3.10%
Discount rate - interest cost on PBO		2.30%	2.80%
Expected long-term rate of return on assets		6.10%	6.10%	3.30%
Rate of increase in compensation levels		2.30%	2.30%	2.20%
Discount rate		2.60%	2.70%
Rate of increase in compensation levels		2.30%	2.30%
PRW
Defined Benefit Plan Disclosure [Line Items]
Discount rate - PBO		4.00%	4.20%
Discount rate - service cost		3.90%	4.10%
Discount rate - interest cost on service cost		3.50%	3.50%
Discount rate - interest cost on PBO		3.30%	3.30%
Expected long-term rate of return on assets		2.00%	2.00%
Health care cost trend - Initial rate		7.00%	7.00%
Health care cost trend - Ultimate rate		5.00%	5.00%
Health care cost trend - ultimate rate year		2,022	2,022
Discount rate		3.50%	4.00%
[1]	This discount rate represents the assumption to determine net periodic benefit cost prior to the Company’s use of the granular approach to calculating service and interest cost which began for the 2016 fiscal year.

Retirement Benefits - Allocatio

Retirement Benefits - Allocation of Plan Assets (Details) - Pension Plans	Dec. 31, 2017
Willis | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Willis | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Willis | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Willis | Equity securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	35.00%
Willis | Equity securities | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	32.00%
Willis | Equity securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	33.00%
Willis | Debt securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	54.00%
Willis | Debt securities | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	27.00%
Willis | Debt securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	47.00%
Willis | Real estate | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	11.00%
Willis | Real estate | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	3.00%
Willis | Real estate | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	2.00%
Willis | Other | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Willis | Other | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	38.00%
Willis | Other | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	18.00%
Towers Watson | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Towers Watson | Canada
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Towers Watson | Germany
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Towers Watson | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Towers Watson | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Towers Watson | Equity securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	23.00%
Towers Watson | Equity securities | Canada
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	60.00%
Towers Watson | Equity securities | Germany
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	30.00%
Towers Watson | Equity securities | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	71.00%
Towers Watson | Equity securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	11.00%
Towers Watson | Debt securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	43.00%
Towers Watson | Debt securities | Canada
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	40.00%
Towers Watson | Debt securities | Germany
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	51.00%
Towers Watson | Debt securities | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	29.00%
Towers Watson | Debt securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	56.00%
Towers Watson | Real estate | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	6.00%
Towers Watson | Real estate | Canada
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Real estate | Germany
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Real estate | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Real estate | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Other | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	28.00%
Towers Watson | Other | Canada
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Other | Germany
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	19.00%
Towers Watson | Other | Ireland
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Towers Watson | Other | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	33.00%
Miller | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	100.00%
Miller | Equity securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	33.00%
Miller | Debt securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	55.00%
Miller | Real estate | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	0.00%
Miller | Other | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset target allocations	12.00%

Retirement Benefits - Fair Valu

Retirement Benefits - Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 9,128	$ 8,109
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	17
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,654	3,280	$ 749
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,910	4,360	3,478
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	562	467	$ 158
Pension Plans | Derivatives | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	16	14
Pension Plans | Derivatives | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	0	0
Pension Plans | Derivatives | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	16	14
Pension Plans | Derivatives | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	0	0
Pension Plans | Repurchase agreements | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	549	0
Pension Plans | Repurchase agreements | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	0	0
Pension Plans | Repurchase agreements | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	549	0
Pension Plans | Repurchase agreements | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan liabilities	0	0
Pension Plans | Cash | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	3
Pension Plans | Cash | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	49
Pension Plans | Cash | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	17
Pension Plans | Cash | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	3
Pension Plans | Cash | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	49
Pension Plans | Cash | Level 1 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	17
Pension Plans | Cash | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Cash | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Cash | Level 2 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Cash | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Cash | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Cash | Level 3 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Short-term securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	283	33
Pension Plans | Short-term securities | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Short-term securities | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	283	33
Pension Plans | Short-term securities | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Equity securities | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	202	260
Pension Plans | Equity securities | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24	382
Pension Plans | Equity securities | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	202	253
Pension Plans | Equity securities | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24	374
Pension Plans | Equity securities | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	8
Pension Plans | Equity securities | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	8
Pension Plans | Equity securities | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Equity securities | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Government bonds | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	10
Pension Plans | Government bonds | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,841	1,184
Pension Plans | Government bonds | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	10
Pension Plans | Government bonds | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,841	1,184
Pension Plans | Government bonds | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Government bonds | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Government bonds | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Government bonds | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Corporate bonds | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	193	170
Pension Plans | Corporate bonds | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	224	118
Pension Plans | Corporate bonds | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Corporate bonds | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Corporate bonds | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	193	169
Pension Plans | Corporate bonds | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	224	118
Pension Plans | Corporate bonds | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Corporate bonds | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Other fixed income | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20	19
Pension Plans | Other fixed income | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	246	216
Pension Plans | Other fixed income | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Other fixed income | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Other fixed income | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20	19
Pension Plans | Other fixed income | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	246	216
Pension Plans | Other fixed income | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Other fixed income | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,922	1,665
Pension Plans | Pooled / commingled funds | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,294	1,677
Pension Plans | Pooled / commingled funds | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	327	214
Pension Plans | Pooled / commingled funds | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 1 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 2 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Pooled / commingled funds | Level 3 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	183
Pension Plans | Mutual funds | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	11
Pension Plans | Mutual funds | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	209	224
Pension Plans | Mutual funds | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	183
Pension Plans | Mutual funds | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 1 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 2 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Mutual funds | Level 3 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	287	234
Pension Plans | Private equity | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32	40
Pension Plans | Private equity | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Private equity | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Derivatives | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	102	73
Pension Plans | Derivatives | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Derivatives | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	102	73
Pension Plans | Derivatives | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Insurance contracts | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	17
Pension Plans | Insurance contracts | Level 1 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Insurance contracts | Level 2 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Insurance contracts | Level 3 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	17
Pension Plans | Real estate | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	218	197
Pension Plans | Real estate | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Real estate | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Real estate | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	724	692
Pension Plans | Hedge funds | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	393	426
Pension Plans | Hedge funds | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Hedge funds | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Assets | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,474	4,373
Pension Plans | Assets | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,957	1,607
Pension Plans | Assets | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	572	415
Pension Plans | Assets | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Investments | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,652	3,269
Pension Plans | Investments | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,909	4,359
Pension Plans | Investments | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	560	472
Pension Plans | Investments | Level 1 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	223	449
Pension Plans | Investments | Level 1 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,957	1,607
Pension Plans | Investments | Level 1 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	17
Pension Plans | Investments | Level 2 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	496	229
Pension Plans | Investments | Level 2 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	401
Pension Plans | Investments | Level 2 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Investments | Level 3 | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Investments | Level 3 | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Plans | Investments | Level 3 | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 19	$ 17

Retirement Benefits - Fair V105

Retirement Benefits - Fair Value Reconciliation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Net assets held in investments	$ 9,121	$ 8,100
PRW plan assets	2	3
Net receivable for investments purchased	2	3
Dividend and interest receivable	3	3
Fair value of plan assets	$ 9,128	$ 8,109

Retirement Benefits - Significa

Retirement Benefits - Significant Unobservable Input Reconciliation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning of year	$ 8,109
Fair value of plan assets, end of year	9,128
Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning of year	17
Foreign exchange	2
Fair value of plan assets, end of year	$ 19

Retirement Benefits - Projected

Retirement Benefits - Projected Benefit Obligation (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 101	$ 91
UNITED STATES | Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	50
Employer contributions	50	50
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	66	106
United Kingdom | Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	81
Employer contributions	65	105
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	34	39
Other Foreign Plans [Member] | Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	13
Employer contributions	$ 13	$ 29

Retirement Benefits - Expected

Retirement Benefits - Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Defined Benefit Plan Disclosure [Line Items]
2,018	$ 394
2,019	390
2,020	407
2,021	424
2,022	445
Years 2023 – 2027	2,446
Expected future benefit payments, total	4,506
Pension Plans | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
2,018	230
2,019	236
2,020	245
2,021	249
2,022	260
Years 2023 – 2027	1,386
Expected future benefit payments, total	2,606
Pension Plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
2,018	112
2,019	111
2,020	117
2,021	127
2,022	129
Years 2023 – 2027	764
Expected future benefit payments, total	1,360
Pension Plans | Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
2,018	36
2,019	26
2,020	27
2,021	29
2,022	36
Years 2023 – 2027	179
Expected future benefit payments, total	333
PRW
Defined Benefit Plan Disclosure [Line Items]
2,018	16
2,019	17
2,020	18
2,021	19
2,022	20
Years 2023 – 2027	117
Expected future benefit payments, total	$ 207

Commitments and Contingencies -

Commitments and Contingencies - Operating Lease Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Rent expense, exclusive of sublease income	$ 302	$ 302	$ 142
Sublease income	21	$ 17	$ 17
Gross rental commitments due 2017	204
Gross rental commitments due 2018	191
Gross rental commitments due 2019	165
Gross rental commitments due 2020	138
Gross rental commitments due 2021	120
Thereafter	585
Gross rental commitments due	1,403
Rentals from subleases due 2017	(16)
Rentals from subleases due 2018	(13)
Rentals from subleases due 2019	(13)
Rentals from subleases due 2020	(10)
Rentals from subleases due 2021	(4)
Rentals from subleases due Thereafter	(5)
Rentals from subleases due	(61)
Net rental commitments due 2017	188
Net rental commitments due 2018	178
Net rental commitments due 2019	152
Net rental commitments due 2020	128
Net rental commitments due 2021	116
Net rental commitments due Thereafter	580
Net rental commitments due	$ 1,342

Commitments and Contingencies O

Commitments and Contingencies Other Commitments (Details) - USD ($) $ in Millions	1 Months Ended			12 Months Ended			80 Months Ended	90 Months Ended
	May 31, 2011	Jul. 31, 2010	Dec. 31, 2009	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2017
Other Commitments [Line Items]
Operating Leases				$ 1,403			$ 1,403	$ 1,403
Capital Lease Obligations				48	$ 54		48	48
Business Combination, Deferred And Contingent Consideration				96			96	96
Payments For Deferred Contingent Consideration, Financing Activities				65	67	$ 0
Amount Payable from Option				34
Property Lease Guarantee [Member]
Other Commitments [Line Items]
Operating Leases				669	558		669	669
Capital Lease Obligations				8	$ 9		8	8
Miller Insurance Services LLP
Other Commitments [Line Items]
Business Combination, Contingent Consideration, Liability				$ 78			78	78
Trident V Parallel Fund [Member]
Other Commitments [Line Items]
Long-term Purchase Commitment, Amount		$ 25
Payments to Acquire Other Investments								$ 24
Trident V LP [Member]
Other Commitments [Line Items]
Long-term Purchase Commitment, Amount			$ 25
Dowling Capital Partners I [Member]
Other Commitments [Line Items]
Long-term Purchase Commitment, Amount	$ 10
Payments to Acquire Other Investments							$ 9

Commitments and Contingencie111

Commitments and Contingencies - Litigation (Details)

Mar. 01, 2017USD ($)

Sep. 12, 2016USD ($)plaintiff

Aug. 05, 2016USD ($)plaintiff

Mar. 31, 2016USD ($)

Jul. 21, 2015

Jul. 15, 2015

Aug. 01, 2014USD ($)

Jan. 10, 2014plaintiff

Oct. 01, 2013USD ($)

Aug. 06, 2013plaintiff

Jun. 20, 2013lawsuit

Jun. 11, 2013lawsuit

Jun. 03, 2013lawsuit

Feb. 14, 2013USD ($)lawsuitplaintiff

Feb. 08, 2013USD ($)plaintiff

Mar. 11, 2011USD ($)plaintiff

Sep. 16, 2010USD ($)plaintiff

Sep. 14, 2009USD ($)plaintiff

Aug. 06, 2009USD ($)

Jul. 02, 2009USD ($)

Mar. 23, 2016complaintshareholdershares

Dec. 10, 2015plaintiff

Mar. 31, 2018USD ($)

Dec. 31, 2017USD ($)subsidiary

Sep. 30, 2017USD ($)$ / shares

Sep. 30, 2016USD ($)

Mar. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2017USD ($)lawsuit

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Jul. 01, 2017USD ($)

May 09, 2016complaint

Mar. 25, 2014

Mar. 25, 2014action

Loss Contingencies [Line Items]

Loss Contingency Accrual, Provision

$ 11,000,000

$ 50,000,000

$ 70,000,000

Elma Sanchez Case [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

3

3

Loss Contingency, Premium Rate Increase

85.00%

Loss Contingency, Damages Paid, Value

$ 9,750,000

Stanford Financial Group [Member]

Loss Contingencies [Line Items]

Loss Contingency, New Claims Filed, Number | lawsuit

15

Stanford Financial Group [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency Accrual, Provision

$ 70,000,000

Troice, et al. v. Willis of Colorado, Inc., et al. [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Damages Sought, Value

$ 1,000,000,000

Loss Contingency, Number of Actions Consolidated

2

2

Canabal, et al. v. Willis of Colorado, Inc., et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Damages Sought, Value

$ 1,000,000,000

Rupert, et al. v. Winter, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

97

Loss Contingency, Damages Sought, Value

$ 300,000,000

Casanova, et al. v. Willis of Colorado, Inc., et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

7

Loss Contingency, Damages Sought, Value

$ 5,000,000

Rishmague, et ano. v. Winter, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

2

Loss Contingency, Damages Sought, Value

$ 37,000,000

MacArthur v. Winter, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

2

Loss Contingency, Damages Sought, Value

$ 4,000,000

Stanford Financial Group, Florida Suits [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, New Claims Filed, Number | lawsuit

5

Loss Contingency, Claims Removed, Number | lawsuit

5

Loss Contingency, Claims Moved to Stay, Number | lawsuit

4

Loss Contingency, Claims Transferred, Number | lawsuit

5

Loss Contingency, Claims Stayed, Period

7 days

Barbar, et al. v. Willis Group Holdings Public Limited Company, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

35

Loss Contingency, Damages Sought, Value

$ 30,000,000

de Gadala-Maria, et al. v. Willis Group Holdings Public Limited Company, et al. [Member]

Loss Contingencies [Line Items]

Loss Contingency, Dismissed Claim, Period to Replead

21 days

de Gadala-Maria, et al. v. Willis Group Holdings Public Limited Company, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

64

Loss Contingency, Damages Sought, Value

$ 83,500,000

Ranni, et ano. v. Willis Group Holdings Public Limited Company, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

2

Loss Contingency, Damages Sought, Value

$ 3,000,000

Tisminesky, et al. v. Willis Group Holdings Public Limited Company, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

11

Loss Contingency, Damages Sought, Value

$ 6,500,000

Loss Contingency, Dismissed Claim, Period to Replead

21 days

Janvey, et al. v. Willis of Colorado, Inc., et al. [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Damages Sought, Value

$ 1,000,000,000

Loss Contingency, Estimate of Possible Loss

$ 4,600,000,000

Zacarias, et al. v. Willis Group Holdings Public Limited Company, et al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

10

Loss Contingency, Damages Sought, Value

$ 12,500,000

Loss Contingency, Dismissed Claim, Period to Replead

21 days

Martin v. Willis of Colorado, Inc., et. al. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

5

1

Loss Contingency, Damages Sought, Value

$ 1,000,000

$ 100,000

Abel, et al. v. Willis of Colorado, Inc., et al [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs | plaintiff

300

Loss Contingency, Damages Sought, Value

$ 135,000,000

Troice and Janvey Cases [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency Accrual, Provision

$ 50,000,000

Litigation Settlement, Amount Awarded to Other Party

$ 120,000,000

$ 120,000,000

City of Houston [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency Accrual, Provision

$ 11,000,000

City of Houston [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Increase to Actuarial Accrued Liability Alleged by Plaintiff

$ 163,000,000

Loss Contingency, Actual Damages Incurred

$ 430,000,000

Loss Contingency, Estimated Future Damages Incurred

$ 400,000,000

Meriter Health Services, Inc. [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Damages Sought, Value

$ 190,000,000

U.K. Investment Consulting Investigation [Member]

Loss Contingencies [Line Items]

Period to conclude

18 months

London Wholesale Insurance Broker Market Study [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Period to conclude

2 years

Number of subsidiaries | subsidiary

2

Towers Watson & Co. | Towers Watson Merger, Demand for Appraisal [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Number of Plaintiffs

3

10

Loss Contingency, Plaintiff's Ownership Percentage

2.40%

Litigation Settlement, Amount Awarded to Other Party

$ 211,000,000

Loss Contingency, Number of Actions Consolidated | complaint

3

Loss Contingency, Number of Shares Owned by Plaintiffs | shares

1,415,199

Settlement Per Share | $ / shares

$ 134.75

Towers Watson & Co. | Towers Watson Merger, Demand for Appraisal [Member] | Pending Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, New Claims Filed, Number | complaint

3

Meriter Health Services, Inc. [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Loss Contingency, Damages Paid, Value

$ 82,000,000

Subsequent Event [Member] | City of Houston [Member] | Settled Litigation [Member]

Loss Contingencies [Line Items]

Litigation Settlement, Amount Awarded to Other Party

$ 40,000,000

Supplementary Information fo112

Supplementary Information for Certain Balance Sheet Accounts - Accounts Receivable, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 2,246	$ 2,080
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	134
Balance at end of year	162	134
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	40	22	$ 12
Additions charged to costs and expenses	17	36	5
Charges to other accounts - Acquisitions	0	8	11
Deductions / Other movements	(9)	(27)	(7)
Foreign exchange differences	(3)	1	1
Balance at end of year	45	40	$ 22
Billed, net of allowance for doubtful debts of $45 million and $40 million
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	1,933	1,789
Allowance for doubtful accounts	45	40
Accrued and unbilled, at estimated net realizable value
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 313	$ 291

Supplementary Information fo113

Supplementary Information for Certain Balance Sheet Accounts - Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepayments and accrued income	$ 132	$ 131
Derivatives and investments	29	32
Deferred compensation plan assets	21	15
Retention incentives	7	7
Corporate income and other taxes	170	97
Other current assets	71	55
Total prepaid and other current assets	$ 430	$ 337

Supplementary Information fo114

Supplementary Information for Certain Balance Sheet Accounts - Other Non-current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepayments and accrued income	$ 18	$ 15
Deferred compensation plan assets	135	111
Deferred tax assets	46	50
Accounts receivable, net	33	27
Other investments	26	30
Other non-current assets	189	120
Total other non-current assets	$ 447	$ 353

Supplementary Information fo115

Supplementary Information for Certain Balance Sheet Accounts - Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable	$ 136	$ 117
Income and other taxes payable	90	91
Contingent and deferred consideration on acquisition	55	53
Payroll-related liabilities	209	200
Derivatives	32	80
Third party commissions	172	184
Other current liabilities	110	151
Total other current liabilities	$ 804	$ 876

Supplementary Information fo116

Supplementary Information for Certain Balance Sheet Accounts - Provision For Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Claims, lawsuits and other proceedings	$ 474	$ 508
Other provisions	84	67
Total provision for liabilities	$ 558	$ 575

Supplementary Information fo117

Supplementary Information for Certain Balance Sheet Accounts - Other Non-current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Incentives from lessors	$ 138	$ 133
Deferred compensation plan liability	135	111
Contingent and deferred consideration on acquisitions	41	89
Derivatives	5	51
Other non-current liabilities	225	148
Total other non-current liabilities	$ 544	$ 532

Other Expense_(Income), Net (De

Other Expense/(Income), Net (Details) $ in Millions	Dec. 29, 2015USD ($)	Dec. 31, 2017USD ($)Bs. / $		Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)Bs. / $		Dec. 28, 2015
Schedule Of Other Expense (Income) [Line Items]
Gain on disposal of operations		$ (13)		$ (2)	$ (25)
Gain on remeasurement of equity interests		0		0	(59)	[1]
Impact of Venezuelan currency devaluation		2	[2]	0	30	[2]
Foreign exchange loss/(gain)		72		29	(1)
Other expense/(income), net		$ 61		$ 27	$ (55)
Gras Savoye
Schedule Of Other Expense (Income) [Line Items]
Gain on remeasurement of equity interests	$ (59)
Ownership percentage							30.00%
Fair value of equity interest	$ 158
SIMADI Exchange Rate
Schedule Of Other Expense (Income) [Line Items]
Foreign currency exchange rate (USD per VEB) | Bs. / $					198.7
SICAD I Exchange Rate
Schedule Of Other Expense (Income) [Line Items]
Foreign currency exchange rate (USD per VEB) | Bs. / $					13.5
DICOM Exchange Rate
Schedule Of Other Expense (Income) [Line Items]
Foreign currency exchange rate (USD per VEB) | Bs. / $		3,345
[1]	Prior to the acquisition date, the Company accounted for its 30% interest in Gras Savoye as an equity-method investment. The acquisition-date fair value of the previously held equity interest was $158 million and is included in the measurement of the consideration transferred. The Company recognized a gain of $59 million as a result of remeasuring its prior equity interest in Gras Savoye held before the business combination.
[2]	(ii)On December 31, 2015 the Company began using the SIMADI rate for the Venezuelan bolivar (approximately Venezuelan bolivars 198.7 = U.S. dollar 1) instead of the SICAD I auction rate (approximately Venezuelan bolivars 13.5 = U.S. dollar 1) to translate on Venezuelan retail operations. In March 2016, the DICOM mechanism replaced the SIMADI mechanism. At December 31, 2017, the DICOM rate was approximately Venezuelan bolivars 3,345 = U.S. dollar 1. The Company does not expect the additional devaluation which occurred in January 2018 to be material.

Accumulated Other Comprehens119

Accumulated Other Comprehensive Loss - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	$ 388	$ (993)	$ 65
Other comprehensive income/(loss), tax	(4)	126	(46)
Other comprehensive income/(loss), net of tax, before non-controlling interests	384	(867)	19
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	295	(353)	(133)
Other comprehensive income/(loss), tax	0	0	0
Other comprehensive income/(loss), net of tax, before non-controlling interests	295	(353)	(133)
Defined pension and post-retirement benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	3	(553)	233
Other comprehensive income/(loss), tax	11	114	(53)
Other comprehensive income/(loss), net of tax, before non-controlling interests	14	(439)	180
Derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	90	(87)	(35)
Other comprehensive income/(loss), tax	(15)	12	7
Other comprehensive income/(loss), net of tax, before non-controlling interests	75	(75)	(28)
AOCI Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	(13)	20	10
Other comprehensive income/(loss), tax	0	0	0
Other comprehensive income/(loss), net of tax, before non-controlling interests	(13)	20	10
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss), before tax	375	(973)	75
Other comprehensive income/(loss), tax	(4)	126	(46)
Other comprehensive income/(loss), net of tax, before non-controlling interests	$ 371	$ (847)	$ 29

Accumulated Other Comprehens120

Accumulated Other Comprehensive Loss - Rollforward of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		$ 10,065
Other comprehensive (loss)/income before reclassifications		287	$ (929)	$ 4
Amounts reclassified from accumulated other comprehensive income (net of income tax)		84	82	25
Other comprehensive income/(loss) before non-controlling interests		371	(847)	29
Ending Balance		10,126	10,065
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(650)	(314)	(191)
Other comprehensive (loss)/income before reclassifications		285	(336)	(123)
Amounts reclassified from accumulated other comprehensive income (net of income tax)		0	0	0
Other comprehensive income/(loss) before non-controlling interests		285	(336)	(123)
Ending Balance		(365)	(650)	(314)
Derivative instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(82)	(10)	18
Other comprehensive (loss)/income before reclassifications		28	(110)	(31)
Amounts reclassified from accumulated other comprehensive income (net of income tax)	[1]	44	38	3
Other comprehensive income/(loss) before non-controlling interests		72	(72)	(28)
Ending Balance		(10)	(82)	(10)
Defined pension and post-retirement benefit costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(1,152)	(713)	(893)
Other comprehensive (loss)/income before reclassifications		(26)	(483)	158
Amounts reclassified from accumulated other comprehensive income (net of income tax)	[2]	40	44	22
Other comprehensive income/(loss) before non-controlling interests		14	(439)	180
Ending Balance		(1,138)	(1,152)	(713)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(1,884)	(1,037)	(1,066)
Ending Balance		$ (1,513)	$ (1,884)	$ (1,037)
[1]	Reclassification adjustments from accumulated other comprehensive income are included in Other expense/(income), net in the accompanying consolidated statements of comprehensive income. See Note 9 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the hedge settlements.
[2]	Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 12 — Retirement Benefits) which is included in Salaries and benefits in the accompanying consolidated statements of comprehensive income.

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details)	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 67,000,000	$ 123,000,000	$ 64,000,000
Tax benefit from compensation expense	22,000,000	35,000,000	15,000,000
Cash received from exercise of stock options	61,000,000	63,000,000	124,000,000
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options	7,000,000	6,000,000	12,000,000
Employee Services Share Based Compensation, Tax Benefit Realized From Vesting Of RSUs	$ 19,000,000	$ 25,000,000	$ 13,000,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares	17,000
Compensation cost not yet recognized	$ 11,000,000
Compensation cost not yet recognized, period for recognition	10 months
Vested (shares) | shares	178,574	459,838	408,032
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 150.81	$ 120.42	$ 117.72
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares	140,000		0
Compensation cost not yet recognized	$ 28,000,000
Compensation cost not yet recognized, period for recognition	1 year 6 months
Vested (shares) | shares	318,714	258,536	63,180
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 140.32	$ 119.75	$ 117.88
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period, weighted average grant date fair value (in dollars per share) | $ / shares	$ 27.69	$ 16.88	$ 14.77
Options, exercises in period, intrinsic value	$ 19,000,000	$ 25,000,000	$ 17,000,000
Compensation cost not yet recognized	$ 2,000,000
Compensation cost not yet recognized, period for recognition	2 years 5 months
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, exercises in period, intrinsic value	$ 10,000,000	$ 9,000,000	$ 25,000,000
Compensation cost not yet recognized, period for recognition	6 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares	0	0	0
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant | shares	7,000,000
Expiration period	10 years
Towers Watson & Co. 2009 Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 11,000,000	$ 31,000,000
Qualified retirement age	55
Qualified years of service	15
Towers Watson & Co. 2009 Long Term Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of the outstanding units			$ 37,000,000
Towers Watson & Co. 2009 Long Term Incentive Plan | Restricted Stock Units (RSU) and Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of the outstanding units			$ 45,000,000
Minimum [Member] | Towers Watson & Co. 2009 Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Qualified years of service in the performance period	1

Share-Based Compensation - Assu

Share-Based Compensation - Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	19.80%	21.00%	17.40%
Expected dividends	1.40%	1.50%	2.70%
Risk-free interest rate	1.60%	0.70%	1.50%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	4 years 2 months	2 years 8 months	4 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	20.20%	20.30%
Expected dividends	0.00%	0.00%
Risk-free interest rate	1.40%	0.80%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	2 years 5 months	2 years 7 months

Share-Based Compensation - Opti

Share-Based Compensation - Options Activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance as of beginning of period, Outstanding (in shares)	1,201,000
Granted, Outstanding (in shares)	38,000
Exercised, Outstanding (in shares)	(448,000)
Forfeited, Outstanding (in shares)	(37,000)
Balance as of end of period, Outstanding (in shares)	754,000
Options vested or expected to vest at end of period, Outstanding (in shares)	751,000
Options exercisable at end of period, Outstanding (in shares)	581,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Balance as of beginning of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 102.38	[1]
Granted, Weighted Average Exercise Price (in dollars per share) | $ / shares	143.60	[1]
Exercised, Weighted Average Exercise Price (in dollars per share) | $ / shares	100.61	[1]
Forfeited, Weighted Average Exercise Price (in dollars per share) | $ / shares	103.22	[1]
Balance as of end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	105.47	[1]
Options vested or expected to vest at end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	105.17	[1]
Options exercisable at end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 101.43	[1]
End of period, Weighted Average Remaining Contractual Term	4 years
Options vested or expected to vest at end of period, Weighted Average Remaining Contractual Term	4 years
Options exercisable at end of period, Weighted Average Remaining Contractual Term	4 years
End of period, Aggregate Intrinsic Value | $	$ 34
Options vested or expected to vest at end of period, Aggregate Intrinsic Value | $	34
Options exercisable at end of period, Aggregate Intrinsic Value | $	$ 29
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance as of beginning of period, Outstanding (in shares)	883,000
Acquired, Outstanding (in shares)	520,295
Exercised, Outstanding (in shares)	(182,000)
Forfeited, Outstanding (in shares)	(21,000)
Balance as of end of period, Outstanding (in shares)	680,000
Options vested or expected to vest at end of period, Outstanding (in shares)	680,000
Options exercisable at end of period, Outstanding (in shares)	190,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Balance as of beginning of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 101.95	[1]
Exercised, Weighted Average Exercise Price (in dollars per share) | $ / shares	87.49	[1]
Forfeited, Weighted Average Exercise Price (in dollars per share) | $ / shares	82.90	[1]
Balance as of end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	106.42	[1]
Options vested or expected to vest at end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	106.42	[1]
Options exercisable at end of period, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 95.36	[1]
End of period, Weighted Average Remaining Contractual Term	4 years
Options vested or expected to vest at end of period, Weighted Average Remaining Contractual Term	4 years
Options exercisable at end of period, Weighted Average Remaining Contractual Term	1 year
End of period, Aggregate Intrinsic Value | $	$ 30
Options vested or expected to vest at end of period, Aggregate Intrinsic Value | $	30
Options exercisable at end of period, Aggregate Intrinsic Value | $	$ 11
[1]	Certain options are exercisable in Pounds sterling and are converted to dollars using the exchange rate at December 31, 2017.

Share-Based Compensation - Nonv

Share-Based Compensation - Nonvested Restricted Stock Units and Performance Based Stock Units Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	10 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance, beginning of year (shares)	437,000
Granted (shares)	17,000
Vested (shares)	(178,574)	(459,838)	(408,032)
Forfeited (shares)	(132,000)
Balance, end of year (shares)	143,000	437,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Balance, beginning of year, Weighted Average Grant Date Fair Value (in dollars per share)	$ 118.98
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	153.40
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	119.50
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	119.09
Balance, end of year, Weighted Average Grant Date Fair Value (in dollars per share)	$ 122.27	$ 118.98
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	6 months
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 6 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance, beginning of year (shares)	1,200,000
Granted (shares)	140,000		0
Vested (shares)	(318,714)	(258,536)	(63,180)
Forfeited (shares)	(140,000)
Balance, end of year (shares)	881,000	1,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Balance, beginning of year, Weighted Average Grant Date Fair Value (in dollars per share)	$ 121.78
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	148.18
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	119.63
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	121.30
Balance, end of year, Weighted Average Grant Date Fair Value (in dollars per share)	$ 90.61	$ 121.78

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Time-based shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share		500,000	600,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share	0	0	500,000
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	754,000	1,201,000
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	680,000	883,000
Time-based shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share units outstanding	100,000	400,000
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share units outstanding	881,000	1,200,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share units outstanding	143,000	437,000

Earnings Per Share - Basic and

Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income attributable to Willis Towers Watson	$ 245	$ (54)	$ 33	$ 344	$ 142	$ (32)	$ 72	$ 238	$ 568	$ 420	$ 373
Basic weighted average number of shares outstanding (shares)									135	137	68	[1]
Dilutive effect of potentially issuable shares (shares)									1	1	1	[1]
Diluted weighted average number of shares outstanding (shares)									136	138	69	[1]
Basic earnings per share (usd per share)	$ 1.85	$ (0.40)	$ 0.24	$ 2.51	$ 1.04	$ (0.23)	$ 0.52	$ 1.76	$ 4.21	$ 3.07	$ 5.49	[1],[2]
Dilutive effect of potentially issuable shares (usd per share)									(0.03)	(0.03)	(0.08)	[1]
Diluted earnings per share (usd per share)	$ 1.84	$ (0.40)	$ 0.24	$ 2.50	$ 1.03	$ (0.23)	$ 0.51	$ 1.75	$ 4.18	$ 3.04	$ 5.41	[1],[2]
[1]	Shares outstanding, potentially issuable shares, basic and diluted earnings per share, and the dilutive effect of potentially issuable shares, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split effected on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.
[2]	Basic and diluted earnings per share and cash dividends declared per share, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.

Supplemental Disclosures of 127

Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental disclosures of cash flow information:
Cash payments for income taxes, net	$ 203	$ 158	$ 91
Cash payments for interest	169	143	126
Cash acquired	0	476	148
Supplemental disclosures of non-cash investing and financing activities:
Issuance of shares and assumed awards in connection with the Merger	0	8,723	0
Fair value of deferred and contingent consideration related to acquisitions	$ 0	$ 0	$ 204

Quarterly Financial Data (Un128

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Total revenues	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	$ 8,202	$ 7,887	$ 3,829
Total costs of providing services	1,968	1,811	1,829	1,856	1,839	1,776	1,813	1,908	7,464	7,336	3,402
Income from operations	110	41	124	463	88	1	136	326	738	551	427
NET INCOME	253	(54)	41	352	148	(31)	76	245	592	438	384
Net income/(loss) attributable to Willis Towers Watson	$ 245	$ (54)	$ 33	$ 344	$ 142	$ (32)	$ 72	$ 238	$ 568	$ 420	$ 373
Earnings/(loss) per share
— Basic (in dollars per share)	$ 1.85	$ (0.40)	$ 0.24	$ 2.51	$ 1.04	$ (0.23)	$ 0.52	$ 1.76	$ 4.21	$ 3.07	$ 5.49	[1],[2]
— Diluted (in dollars per share)	$ 1.84	$ (0.40)	$ 0.24	$ 2.50	$ 1.03	$ (0.23)	$ 0.51	$ 1.75	$ 4.18	$ 3.04	$ 5.41	[1],[2]
[1]	Basic and diluted earnings per share and cash dividends declared per share, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.
[2]	Shares outstanding, potentially issuable shares, basic and diluted earnings per share, and the dilutive effect of potentially issuable shares, for the year ended December 31, 2015 have been retroactively adjusted to reflect the reverse stock split effected on January 4, 2016. See Note 3 — Merger, Acquisitions and Divestitures for further details.

Quarterly Financial Data (Un129

Quarterly Financial Data (Unaudited) - Error Correction (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Benefit from income taxes		$ 100	$ 96	$ 33
Valuation Allowance of Deferred Tax Assets
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Benefit from income taxes	$ 103

Financial Information for Pa130

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Narrative (Details) - USD ($)	Dec. 31, 2017	May 16, 2017	Sep. 29, 2009	Mar. 28, 2007
Debt Instrument [Line Items]
Long-term debt	$ 5,638,000,000
Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 3,506,000,000
The Other Guarantors
Debt Instrument [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	10000.00%
Willis North America | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 837,000,000
Debt Instrument, Face Amount		$ 650,000,000	$ 187,000,000	$ 394,000,000

Financial Information for Pa131

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Commissions and fees									$ 8,116	$ 7,778	$ 3,809
Interest and other income									86	109	20
Total revenues	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	8,202	7,887	3,829
Costs of providing services
Salaries and benefits									4,745	4,646	2,303
Other operating expenses									1,534	1,551	718
Depreciation expense									203	178	95
Amortization									(581)	(591)	(76)
Restructuring costs									132	193	126
Integration expenses									(269)	(177)	(84)
Total costs of providing services	1,968	1,811	1,829	1,856	1,839	1,776	1,813	1,908	7,464	7,336	3,402
Income from operations	110	41	124	463	88	1	136	326	738	551	427
Income from Group undertakings									0	0	0
Expenses due to Group undertakings									0	0	0
Interest expense									188	184	142
Other (income)/expense, net									61	27	(55)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									489	340	340
Provision for income taxes									(100)	(96)	(33)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									589	436	373
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(11)
Equity account for subsidiaries									0	0	0
NET INCOME	253	(54)	41	352	148	(31)	76	245	592	438	384
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$ 245	$ (54)	$ 33	$ 344	$ 142	$ (32)	$ 72	$ 238	568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									976	(429)	403
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
Consolidating adjustments | Parent Guarantor
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									0	0	0
Depreciation expense									0	0	0
Amortization									3	0	0
Restructuring costs									0	0	0
Integration expenses									0	0	0
Total costs of providing services									(3)	0	0
Income from operations									3	0	0
Income from Group undertakings									902	926	571
Expenses due to Group undertakings									(902)	(926)	(571)
Interest expense									0	0	0
Other (income)/expense, net									238	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									(1,094)	(849)	(892)
NET INCOME									(1,329)	(849)	(892)
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									(1,329)	(849)	(892)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									(2,163)	1,194	(965)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(2,163)	1,194	(965)
Willis Towers Watson | Reportable Legal Entities
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									4	2	1
Other operating expenses									3	3	8
Depreciation expense									0	0	0
Amortization									0	0	0
Restructuring costs									0	0	0
Integration expenses									0	(1)	(4)
Total costs of providing services									7	6	13
Income from operations									(7)	(6)	(13)
Income from Group undertakings									0	(3)	0
Expenses due to Group undertakings									0	3	0
Interest expense									30	32	43
Other (income)/expense, net									(35)	0	10
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									570	458	439
NET INCOME									568	420	373
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									939	(427)	402
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
The Other Guarantors | Reportable Legal Entities
Revenues
Commissions and fees									0	0	0
Interest and other income									0	2	1
Total revenues									0	2	1
Costs of providing services
Salaries and benefits									0	1	0
Other operating expenses									92	112	100
Depreciation expense									6	5	6
Amortization									(3)	0	0
Restructuring costs									8	29	28
Integration expenses									(73)	(16)	(14)
Total costs of providing services									182	163	148
Income from operations									(182)	(161)	(147)
Income from Group undertakings									(535)	(500)	(225)
Expenses due to Group undertakings									62	74	31
Interest expense									102	89	39
Other (income)/expense, net									0	(2)	(42)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									189	178	50
Provision for income taxes									(51)	(36)	(29)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									240	214	79
Interest in (loss)/earnings of associates, net of tax									0	0	(9)
Equity account for subsidiaries									353	234	347
NET INCOME									593	448	435
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									593	448	435
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									953	(380)	462
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									953	(380)	462
The Issuer | Reportable Legal Entities
Revenues
Commissions and fees									19	19	11
Interest and other income									0	0	0
Total revenues									19	19	11
Costs of providing services
Salaries and benefits									48	15	77
Other operating expenses									20	88	1
Depreciation expense									0	14	16
Amortization									0	0	0
Restructuring costs									15	39	13
Integration expenses									(19)	(26)	0
Total costs of providing services									102	182	107
Income from operations									(83)	(163)	(96)
Income from Group undertakings									(219)	(287)	(236)
Expenses due to Group undertakings									185	178	189
Interest expense									35	39	42
Other (income)/expense, net									0	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(84)	(93)	(91)
Provision for income taxes									29	(86)	(17)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(113)	(7)	(74)
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									171	157	106
NET INCOME									58	150	32
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									58	150	32
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									197	(266)	49
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									197	(266)	49
Other | Reportable Legal Entities
Revenues
Commissions and fees									8,097	7,759	3,798
Interest and other income									86	107	19
Total revenues									8,183	7,866	3,817
Costs of providing services
Salaries and benefits									4,693	4,628	2,225
Other operating expenses									1,419	1,348	609
Depreciation expense									197	159	73
Amortization									(581)	(591)	(76)
Restructuring costs									109	125	85
Integration expenses									(177)	(134)	(66)
Total costs of providing services									7,176	6,985	3,134
Income from operations									1,007	881	683
Income from Group undertakings									(148)	(136)	(110)
Expenses due to Group undertakings									655	671	351
Interest expense									21	24	18
Other (income)/expense, net									(142)	29	(23)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									621	293	447
Provision for income taxes									(78)	26	13
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									699	267	434
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(2)
Equity account for subsidiaries									0	0	0
NET INCOME									702	269	436
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									678	251	425
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									1,050	(550)	455
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									$ 1,013	$ (548)	$ 454

Financial Information for Pa132

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Balance Sheet (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 1,030,000,000	$ 870,000,000	$ 532,000,000	$ 635,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,246,000,000	2,080,000,000
Prepaid and other current assets	430,000,000	337,000,000
Amounts due from group undertakings	0	0
Total current assets	15,861,000,000	13,792,000,000
Investments in subsidiaries	0	0
Fixed assets, net	985,000,000	839,000,000
Goodwill	10,519,000,000	10,413,000,000	3,737,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	447,000,000	353,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,597,000,000	16,461,000,000
TOTAL ASSETS	32,458,000,000	30,253,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,711,000,000	1,481,000,000
Short-term debt and current portion of long-term debt	85,000,000	508,000,000
Other current liabilities	804,000,000	876,000,000
Amounts due to group undertakings	0	0
Total current liabilities	14,755,000,000	13,370,000,000
Long-term debt	4,450,000,000	3,357,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	615,000,000	864,000,000
Provision for liabilities	558,000,000	575,000,000
Other non-current liabilities	544,000,000	532,000,000
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	7,426,000,000	6,649,000,000
TOTAL LIABILITIES	22,181,000,000	20,019,000,000
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,249,000,000	10,183,000,000	2,360,000,000	2,007,000,000
TOTAL LIABILITIES AND EQUITY	32,458,000,000	30,253,000,000
Consolidating adjustments | Parent Guarantor
ASSETS
Cash and cash equivalents	0	0	0	0
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	(146,000,000)	(59,000,000)
Amounts due from group undertakings	(12,820,000,000)	(12,495,000,000)
Total current assets	(12,966,000,000)	(12,554,000,000)
Investments in subsidiaries	(19,467,000,000)	(16,622,000,000)
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	(60,000,000)	(64,000,000)
Pension benefits assets	0	0
Other non-current assets	(90,000,000)	(47,000,000)
Non-current amounts due from group undertakings	(6,236,000,000)	(5,491,000,000)
Total non-current assets	(25,853,000,000)	(22,224,000,000)
TOTAL ASSETS	(38,819,000,000)	(34,778,000,000)
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	(49,000,000)
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	(150,000,000)	(2,000,000)
Amounts due to group undertakings	(12,820,000,000)	(12,495,000,000)
Total current liabilities	(12,970,000,000)	(12,546,000,000)
Long-term debt	0	0
Liability for pension benefits	0	0
Deferred tax liabilities	(89,000,000)	(149,000,000)
Provision for liabilities	0	0
Other non-current liabilities	0	(14,000,000)
Non-current amounts due to group undertakings	(6,236,000,000)	(5,491,000,000)
Total non-current liabilities	(6,325,000,000)	(5,654,000,000)
TOTAL LIABILITIES	(19,295,000,000)	(18,200,000,000)
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	(19,524,000,000)	(16,578,000,000)
Non-controlling interests	0	0
Total equity	(19,524,000,000)	(16,578,000,000)
TOTAL LIABILITIES AND EQUITY	(38,819,000,000)	(34,778,000,000)
Willis Towers Watson | Reportable Legal Entities
ASSETS
Cash and cash equivalents	2,000,000	0	3,000,000	9,000,000
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	0	0
Amounts due from group undertakings	6,202,000,000	7,229,000,000
Total current assets	6,204,000,000	7,229,000,000
Investments in subsidiaries	4,506,000,000	3,409,000,000
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Pension benefits assets	0	0
Other non-current assets	0	0
Non-current amounts due from group undertakings	0	0
Total non-current assets	4,506,000,000	3,409,000,000
TOTAL ASSETS	10,710,000,000	10,638,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	0
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	87,000,000	77,000,000
Amounts due to group undertakings	0	0
Total current liabilities	87,000,000	77,000,000
Long-term debt	497,000,000	496,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	0	0
Other non-current liabilities	0	0
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	497,000,000	496,000,000
TOTAL LIABILITIES	584,000,000	573,000,000
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	0	0
Total equity	10,126,000,000	10,065,000,000
TOTAL LIABILITIES AND EQUITY	10,710,000,000	10,638,000,000
The Other Guarantors | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1,000,000	0	2,000,000	2,000,000
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	45,000,000	49,000,000
Amounts due from group undertakings	1,331,000,000	1,706,000,000
Total current assets	1,377,000,000	1,755,000,000
Investments in subsidiaries	8,836,000,000	7,733,000,000
Fixed assets, net	25,000,000	34,000,000
Goodwill	0	0
Other intangible assets, net	60,000,000	64,000,000
Pension benefits assets	0	0
Other non-current assets	34,000,000	10,000,000
Non-current amounts due from group undertakings	5,375,000,000	4,655,000,000
Total non-current assets	14,330,000,000	12,496,000,000
TOTAL ASSETS	15,707,000,000	14,251,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	7,000,000	15,000,000
Short-term debt and current portion of long-term debt	0	22,000,000
Other current liabilities	60,000,000	94,000,000
Amounts due to group undertakings	8,100,000,000	8,323,000,000
Total current liabilities	8,167,000,000	8,454,000,000
Long-term debt	2,883,000,000	2,506,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	0	0
Other non-current liabilities	5,000,000	48,000,000
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	2,888,000,000	2,554,000,000
TOTAL LIABILITIES	11,055,000,000	11,008,000,000
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	4,652,000,000	3,243,000,000
Non-controlling interests	0	0
Total equity	4,652,000,000	3,243,000,000
TOTAL LIABILITIES AND EQUITY	15,707,000,000	14,251,000,000
The Issuer | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Fiduciary assets	0	0
Accounts receivable, net	4,000,000	7,000,000
Prepaid and other current assets	267,000,000	23,000,000
Amounts due from group undertakings	1,661,000,000	1,190,000,000
Total current assets	1,932,000,000	1,220,000,000
Investments in subsidiaries	6,125,000,000	5,480,000,000
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Pension benefits assets	0	0
Other non-current assets	115,000,000	80,000,000
Non-current amounts due from group undertakings	861,000,000	836,000,000
Total non-current assets	7,101,000,000	6,396,000,000
TOTAL ASSETS	9,033,000,000	7,616,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	19,000,000	27,000,000
Short-term debt and current portion of long-term debt	0	394,000,000
Other current liabilities	83,000,000	23,000,000
Amounts due to group undertakings	2,790,000,000	2,075,000,000
Total current liabilities	2,892,000,000	2,519,000,000
Long-term debt	986,000,000	186,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	120,000,000	120,000,000
Other non-current liabilities	19,000,000	15,000,000
Non-current amounts due to group undertakings	519,000,000	518,000,000
Total non-current liabilities	1,644,000,000	839,000,000
TOTAL LIABILITIES	4,536,000,000	3,358,000,000
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	4,497,000,000	4,258,000,000
Non-controlling interests	0	0
Total equity	4,497,000,000	4,258,000,000
TOTAL LIABILITIES AND EQUITY	9,033,000,000	7,616,000,000
Other | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1,027,000,000	870,000,000	$ 527,000,000	$ 624,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,242,000,000	2,073,000,000
Prepaid and other current assets	264,000,000	324,000,000
Amounts due from group undertakings	3,626,000,000	2,370,000,000
Total current assets	19,314,000,000	16,142,000,000
Investments in subsidiaries	0	0
Fixed assets, net	960,000,000	805,000,000
Goodwill	10,519,000,000	10,413,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	388,000,000	310,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,513,000,000	16,384,000,000
TOTAL ASSETS	35,827,000,000	32,526,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,685,000,000	1,488,000,000
Short-term debt and current portion of long-term debt	85,000,000	92,000,000
Other current liabilities	724,000,000	684,000,000
Amounts due to group undertakings	1,930,000,000	2,097,000,000
Total current liabilities	16,579,000,000	14,866,000,000
Long-term debt	84,000,000	169,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	704,000,000	1,013,000,000
Provision for liabilities	438,000,000	455,000,000
Other non-current liabilities	520,000,000	483,000,000
Non-current amounts due to group undertakings	5,717,000,000	4,973,000,000
Total non-current liabilities	8,722,000,000	8,414,000,000
TOTAL LIABILITIES	25,301,000,000	23,280,000,000
EQUITY (i)
REDEEMABLE NONCONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,375,000,000	9,077,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,498,000,000	9,195,000,000
TOTAL LIABILITIES AND EQUITY	$ 35,827,000,000	$ 32,526,000,000

Financial Information for Pa133

Financial Information for Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$ 862	$ 933	$ 244
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(300)	(218)	(146)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(1)	44
Other, net	(4)	23	16
Proceeds from intercompany investing activities	0	0	0
Repayments of intercompany investing activities	0	0	0
Reduction in investment in subsidiaries	0	0
Additional investment in subsidiaries	0	0	0
Net cash (used in)/from investing activities	(335)	195	(943)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	642	(237)	469
Senior notes issued	649	1,606	0
Proceeds from issuance of other debt	32	404	592
Debt issuance costs	(9)	(14)	(5)
Repayments of debt	(734)	(1,901)	(166)
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	131
Payments for share cancellation related to legal settlement	(177)	0	0
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)	0
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(479)	(775)	640
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	48	353	(59)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	532	635
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,030	870	532
Consolidating adjustments | Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(209)	(206)	(150)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	94	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	3	0
Other, net	0	(30)	0
Proceeds from intercompany investing activities	(3,624)	(193)	(608)
Repayments of intercompany investing activities	2,790	8,634	1,009
Reduction in investment in subsidiaries	(2,010)	(8,200)
Additional investment in subsidiaries	2,010	8,200	598
Net cash (used in)/from investing activities	(834)	8,508	999
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	0	0
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	(598)
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	209	139	150
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	(2,790)	(8,634)	(1,009)
Repayments of intercompany financing activities	3,624	193	608
Net cash provided by (used in) financing activities	1,043	(8,302)	(849)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Willis Towers Watson | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	743	(20)	(10)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	0	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	0	0
Proceeds from intercompany investing activities	1,042	0	321
Repayments of intercompany investing activities	0	(3,751)	(82)
Reduction in investment in subsidiaries	104	4,600
Additional investment in subsidiaries	(1,139)	0	0
Net cash (used in)/from investing activities	7	849	239
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	(300)	0
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	124
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(748)	(832)	(235)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	2	(3)	(6)
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	3	9
CASH AND CASH EQUIVALENTS, END OF PERIOD	2	0	3
The Other Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(725)	128	583
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(8)	(79)	(10)
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	0	0
Proceeds from intercompany investing activities	1,326	163	49
Repayments of intercompany investing activities	(994)	(4,114)	(746)
Reduction in investment in subsidiaries	1,188	3,600
Additional investment in subsidiaries	(503)	(4,600)	(598)
Net cash (used in)/from investing activities	1,009	(5,030)	(1,305)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	487	(237)	469
Senior notes issued	0	1,606
Proceeds from issuance of other debt	0	400	592
Debt issuance costs	(4)	(14)	(5)
Repayments of debt	(220)	(1,037)	(16)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	0
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	0	0	0
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	1,518	4,204	154
Repayments of intercompany financing activities	(2,064)	(22)	(472)
Net cash provided by (used in) financing activities	(283)	4,900	722
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	1	(2)	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	2	2
CASH AND CASH EQUIVALENTS, END OF PERIOD	1	0	2
The Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	114	(83)	43
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	(12)	(8)
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	33	0
Proceeds from intercompany investing activities	19	0	87
Repayments of intercompany investing activities	(74)	0	0
Reduction in investment in subsidiaries	100	0
Additional investment in subsidiaries	(215)	0	0
Net cash (used in)/from investing activities	(170)	21	79
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	155	0	0
Senior notes issued	649	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	(5)	0	0
Repayments of debt	(394)	0	(149)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	0
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	(58)	(49)	0
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	203	164	27
Repayments of intercompany financing activities	(494)	(53)	0
Net cash provided by (used in) financing activities	56	62	(122)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Other | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	939	1,114	(222)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(292)	(221)	(128)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(4)	44
Other, net	(4)	20	16
Proceeds from intercompany investing activities	1,237	30	151
Repayments of intercompany investing activities	(1,722)	(769)	(181)
Reduction in investment in subsidiaries	618	0
Additional investment in subsidiaries	(153)	(3,600)	0
Net cash (used in)/from investing activities	(347)	(4,153)	(955)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	32	4	0
Debt issuance costs	0	0	0
Repayments of debt	(120)	(564)	(1)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	605
Payments for share cancellation related to legal settlement	(177)
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(151)	(90)	(150)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	1,069	4,266	828
Repayments of intercompany financing activities	(1,066)	(118)	(136)
Net cash provided by (used in) financing activities	(547)	3,397	1,124
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	45	358	(53)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	527	624
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 1,027	$ 870	$ 527

Financial Information for Pa134

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Narrative (Details) - USD ($) $ in Millions	Mar. 15, 2016	Dec. 31, 2017	Mar. 16, 2016	Mar. 17, 2011
Debt Instrument [Line Items]
Long-term debt		$ 5,638
Senior Notes
Debt Instrument [Line Items]
Long-term debt		$ 3,506
The Other Guarantors
Debt Instrument [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		10000.00%
Willis Towers Watson | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 800
Repayments of debt	$ 300
Long-term debt			$ 500

Financial Information for Pa135

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Commissions and fees									$ 8,116	$ 7,778	$ 3,809
Interest and other income									86	109	20
Total revenues	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	8,202	7,887	3,829
Costs of providing services
Salaries and benefits									4,745	4,646	2,303
Other operating expenses									1,534	1,551	718
Depreciation expense									203	178	95
Amortization									(581)	(591)	(76)
Restructuring costs									132	193	126
Integration expenses									(269)	(177)	(84)
Total costs of providing services	1,968	1,811	1,829	1,856	1,839	1,776	1,813	1,908	7,464	7,336	3,402
Income from operations	110	41	124	463	88	1	136	326	738	551	427
Income from Group undertakings									0	0	0
Expenses due to Group undertakings									0	0	0
Interest expense									188	184	142
Other (income)/expense, net									61	27	(55)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									489	340	340
Provision for income taxes									(100)	(96)	(33)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									589	436	373
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(11)
Equity account for subsidiaries									0	0	0
NET INCOME	253	(54)	41	352	148	(31)	76	245	592	438	384
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$ 245	$ (54)	$ 33	$ 344	$ 142	$ (32)	$ 72	$ 238	568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									976	(429)	403
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
Consolidating adjustments | Parent Issuer
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									0	0	0
Depreciation expense									0	0	0
Amortization									3	0	0
Restructuring costs									0	0	0
Integration expenses									0	0	0
Total costs of providing services									(3)	0	0
Income from operations									3	0	0
Income from Group undertakings									793	811	460
Expenses due to Group undertakings									(793)	(811)	(460)
Interest expense									0	0	0
Other (income)/expense, net									238	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									(1,036)	(699)	(860)
NET INCOME									(1,271)	(699)	(860)
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									(1,271)	(699)	(860)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									(1,966)	928	(916)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(1,966)	928	(916)
Willis Towers Watson — the Parent Issuer | Reportable Legal Entities
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									4	2	1
Other operating expenses									3	3	8
Depreciation expense									0	0	0
Amortization									0	0	0
Restructuring costs									0	0	0
Integration expenses									0	(1)	(4)
Total costs of providing services									7	6	13
Income from operations									(7)	(6)	(13)
Income from Group undertakings									0	(3)	0
Expenses due to Group undertakings									0	3	0
Interest expense									30	32	43
Other (income)/expense, net									(35)	0	10
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									570	458	439
NET INCOME									568	420	373
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									939	(427)	402
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
The Guarantors | Reportable Legal Entities
Revenues
Commissions and fees									19	19	11
Interest and other income									0	2	1
Total revenues									19	21	12
Costs of providing services
Salaries and benefits									48	16	77
Other operating expenses									112	200	101
Depreciation expense									6	19	22
Amortization									(3)	0	0
Restructuring costs									23	68	41
Integration expenses									(92)	(42)	(14)
Total costs of providing services									284	345	255
Income from operations									(265)	(324)	(243)
Income from Group undertakings									(645)	(672)	(350)
Expenses due to Group undertakings									138	137	109
Interest expense									137	128	81
Other (income)/expense, net									0	(2)	(42)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									105	85	(41)
Provision for income taxes									(22)	(122)	(46)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									127	207	5
Interest in (loss)/earnings of associates, net of tax									0	0	(9)
Equity account for subsidiaries									466	241	421
NET INCOME									593	448	435
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									593	448	435
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									953	(380)	462
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									953	(380)	462
Other | Reportable Legal Entities
Revenues
Commissions and fees									8,097	7,759	3,798
Interest and other income									86	107	19
Total revenues									8,183	7,866	3,817
Costs of providing services
Salaries and benefits									4,693	4,628	2,225
Other operating expenses									1,419	1,348	609
Depreciation expense									197	159	73
Amortization									(581)	(591)	(76)
Restructuring costs									109	125	85
Integration expenses									(177)	(134)	(66)
Total costs of providing services									7,176	6,985	3,134
Income from operations									1,007	881	683
Income from Group undertakings									(148)	(136)	(110)
Expenses due to Group undertakings									655	671	351
Interest expense									21	24	18
Other (income)/expense, net									(142)	29	(23)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									621	293	447
Provision for income taxes									(78)	26	13
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									699	267	434
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(2)
Equity account for subsidiaries									0	0	0
NET INCOME									702	269	436
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									678	251	425
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									1,050	(550)	455
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									$ 1,013	$ (548)	$ 454

Financial Information for Pa136

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Balance Sheet (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 1,030,000,000	$ 870,000,000	$ 532,000,000	$ 635,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,246,000,000	2,080,000,000
Prepaid and other current assets	430,000,000	337,000,000
Amounts due from group undertakings	0	0
Total current assets	15,861,000,000	13,792,000,000
Investments in subsidiaries	0	0
Fixed assets, net	985,000,000	839,000,000
Goodwill	10,519,000,000	10,413,000,000	3,737,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	447,000,000	353,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,597,000,000	16,461,000,000
TOTAL ASSETS	32,458,000,000	30,253,000,000
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,711,000,000	1,481,000,000
Short-term debt and current portion of long-term debt	85,000,000	508,000,000
Other current liabilities	804,000,000	876,000,000
Amounts due to group undertakings	0	0
Total current liabilities	14,755,000,000	13,370,000,000
Long-term debt	4,450,000,000	3,357,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	615,000,000	864,000,000
Provision for liabilities	558,000,000	575,000,000
Other non-current liabilities	544,000,000	532,000,000
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	7,426,000,000	6,649,000,000
TOTAL LIABILITIES	22,181,000,000	20,019,000,000
REDEEMABLE NONCONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,249,000,000	10,183,000,000	2,360,000,000	2,007,000,000
TOTAL LIABILITIES AND EQUITY	32,458,000,000	30,253,000,000
Consolidating adjustments | Parent Issuer
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	(146,000,000)	(59,000,000)
Amounts due from group undertakings	(11,777,000,000)	(11,247,000,000)
Total current assets	(11,923,000,000)	(11,306,000,000)
Investments in subsidiaries	(14,969,000,000)	(12,364,000,000)
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	(60,000,000)	(64,000,000)
Pension benefits assets	0	0
Other non-current assets	(90,000,000)	(47,000,000)
Non-current amounts due from group undertakings	(5,717,000,000)	(4,973,000,000)
Total non-current assets	(20,836,000,000)	(17,448,000,000)
TOTAL ASSETS	(32,759,000,000)	(28,754,000,000)
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	(49,000,000)
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	(150,000,000)	(2,000,000)
Amounts due to group undertakings	(11,776,000,000)	(11,247,000,000)
Total current liabilities	(11,926,000,000)	(11,298,000,000)
Long-term debt	0	0
Liability for pension benefits	0	0
Deferred tax liabilities	(89,000,000)	(149,000,000)
Provision for liabilities	0	0
Other non-current liabilities	0	(14,000,000)
Non-current amounts due to group undertakings	(5,717,000,000)	(4,973,000,000)
Total non-current liabilities	(5,806,000,000)	(5,136,000,000)
TOTAL LIABILITIES	(17,732,000,000)	(16,434,000,000)
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	(15,027,000,000)	(12,320,000,000)
Non-controlling interests	0	0
Total equity	(15,027,000,000)	(12,320,000,000)
TOTAL LIABILITIES AND EQUITY	(32,759,000,000)	(28,754,000,000)
Willis Towers Watson — the Parent Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	2,000,000	0	3,000,000	9,000,000
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	0	0
Amounts due from group undertakings	6,202,000,000	7,229,000,000
Total current assets	6,204,000,000	7,229,000,000
Investments in subsidiaries	4,506,000,000	3,409,000,000
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Pension benefits assets	0	0
Other non-current assets	0	0
Non-current amounts due from group undertakings	0	0
Total non-current assets	4,506,000,000	3,409,000,000
TOTAL ASSETS	10,710,000,000	10,638,000,000
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	0
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	87,000,000	77,000,000
Amounts due to group undertakings	0	0
Total current liabilities	87,000,000	77,000,000
Long-term debt	497,000,000	496,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	0	0
Other non-current liabilities	0	0
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	497,000,000	496,000,000
TOTAL LIABILITIES	584,000,000	573,000,000
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	0	0
Total equity	10,126,000,000	10,065,000,000
TOTAL LIABILITIES AND EQUITY	10,710,000,000	10,638,000,000
The Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	1,000,000	0	2,000,000	2,000,000
Fiduciary assets	0	0
Accounts receivable, net	4,000,000	7,000,000
Prepaid and other current assets	312,000,000	72,000,000
Amounts due from group undertakings	1,949,000,000	1,648,000,000
Total current assets	2,266,000,000	1,727,000,000
Investments in subsidiaries	10,463,000,000	8,955,000,000
Fixed assets, net	25,000,000	34,000,000
Goodwill	0	0
Other intangible assets, net	60,000,000	64,000,000
Pension benefits assets	0	0
Other non-current assets	149,000,000	90,000,000
Non-current amounts due from group undertakings	5,717,000,000	4,973,000,000
Total non-current assets	16,414,000,000	14,116,000,000
TOTAL ASSETS	18,680,000,000	15,843,000,000
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	26,000,000	42,000,000
Short-term debt and current portion of long-term debt	0	416,000,000
Other current liabilities	143,000,000	117,000,000
Amounts due to group undertakings	9,846,000,000	9,150,000,000
Total current liabilities	10,015,000,000	9,725,000,000
Long-term debt	3,869,000,000	2,692,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	120,000,000	120,000,000
Other non-current liabilities	24,000,000	63,000,000
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	4,013,000,000	2,875,000,000
TOTAL LIABILITIES	14,028,000,000	12,600,000,000
REDEEMABLE NONCONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	4,652,000,000	3,243,000,000
Non-controlling interests	0	0
Total equity	4,652,000,000	3,243,000,000
TOTAL LIABILITIES AND EQUITY	18,680,000,000	15,843,000,000
Other | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	1,027,000,000	870,000,000	$ 527,000,000	$ 624,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,242,000,000	2,073,000,000
Prepaid and other current assets	264,000,000	324,000,000
Amounts due from group undertakings	3,626,000,000	2,370,000,000
Total current assets	19,314,000,000	16,142,000,000
Investments in subsidiaries	0	0
Fixed assets, net	960,000,000	805,000,000
Goodwill	10,519,000,000	10,413,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	388,000,000	310,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,513,000,000	16,384,000,000
TOTAL ASSETS	35,827,000,000	32,526,000,000
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,685,000,000	1,488,000,000
Short-term debt and current portion of long-term debt	85,000,000	92,000,000
Other current liabilities	724,000,000	684,000,000
Amounts due to group undertakings	1,930,000,000	2,097,000,000
Total current liabilities	16,579,000,000	14,866,000,000
Long-term debt	84,000,000	169,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	704,000,000	1,013,000,000
Provision for liabilities	438,000,000	455,000,000
Other non-current liabilities	520,000,000	483,000,000
Non-current amounts due to group undertakings	5,717,000,000	4,973,000,000
Total non-current liabilities	8,722,000,000	8,414,000,000
TOTAL LIABILITIES	25,301,000,000	23,280,000,000
REDEEMABLE NONCONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,375,000,000	9,077,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,498,000,000	9,195,000,000
TOTAL LIABILITIES AND EQUITY	$ 35,827,000,000	$ 32,526,000,000

Financial Information for Pa137

Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$ 862	$ 933	$ 244
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(300)	(218)	(146)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(1)	44
Other, net	(4)	23	16
Proceeds from intercompany investing activities	0	0	0
Repayments of intercompany investing activities	0	0	0
Reduction in investment in subsidiaries	0	0
Additional investment in subsidiaries	0	0	0
Net cash (used in)/from investing activities	(335)	195	(943)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	642	(237)	469
Senior notes issued	649	1,606	0
Proceeds from issuance of other debt	32	404	592
Debt issuance costs	(9)	(14)	(5)
Repayments of debt	(734)	(1,901)	(166)
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	131
Payments for share cancellation related to legal settlement	(177)	0	0
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)	0
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(479)	(775)	640
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	48	353	(59)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	532	635
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,030	870	532
Consolidating adjustments | Parent Issuer
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(151)	(157)	(150)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	94	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	3	0
Other, net	0	(30)	0
Proceeds from intercompany investing activities	(3,311)	(148)	(608)
Repayments of intercompany investing activities	2,790	8,634	1,009
Reduction in investment in subsidiaries	(2,010)	(8,200)
Additional investment in subsidiaries	2,010	8,200	598
Net cash (used in)/from investing activities	(521)	8,553	999
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	0	0
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	(598)
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	151	90	150
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	(2,790)	(8,634)	(1,009)
Repayments of intercompany financing activities	3,311	148	608
Net cash provided by (used in) financing activities	672	(8,396)	(849)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Consolidating adjustments | Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(209)	(206)	(150)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	94	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	3	0
Other, net	0	(30)	0
Proceeds from intercompany investing activities	(3,624)	(193)	(608)
Repayments of intercompany investing activities	2,790	8,634	1,009
Reduction in investment in subsidiaries	(2,010)	(8,200)
Additional investment in subsidiaries	2,010	8,200	598
Net cash (used in)/from investing activities	(834)	8,508	999
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	0	0
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	(598)
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	209	139	150
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	(2,790)	(8,634)	(1,009)
Repayments of intercompany financing activities	3,624	193	608
Net cash provided by (used in) financing activities	1,043	(8,302)	(849)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Willis Towers Watson — the Parent Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	743	(20)	(10)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	0	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	0	0
Proceeds from intercompany investing activities	1,042	0	321
Repayments of intercompany investing activities	0	(3,751)	(82)
Reduction in investment in subsidiaries	104	4,600
Additional investment in subsidiaries	(1,139)	0	0
Net cash (used in)/from investing activities	7	849	239
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	(300)	0
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	124
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(748)	(832)	(235)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	2	(3)	(6)
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	3	9
CASH AND CASH EQUIVALENTS, END OF PERIOD	2	0	3
Other | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	939	1,114	(222)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(292)	(221)	(128)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(4)	44
Other, net	(4)	20	16
Proceeds from intercompany investing activities	1,237	30	151
Repayments of intercompany investing activities	(1,722)	(769)	(181)
Reduction in investment in subsidiaries	618	0
Additional investment in subsidiaries	(153)	(3,600)	0
Net cash (used in)/from investing activities	(347)	(4,153)	(955)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	32	4	0
Debt issuance costs	0	0	0
Repayments of debt	(120)	(564)	(1)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	605
Payments for share cancellation related to legal settlement	(177)
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(151)	(90)	(150)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	1,069	4,266	828
Repayments of intercompany financing activities	(1,066)	(118)	(136)
Net cash provided by (used in) financing activities	(547)	3,397	1,124
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	45	358	(53)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	527	624
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,027	870	527
The Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(669)	(4)	626
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(8)	(91)	(18)
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	33	0
Proceeds from intercompany investing activities	1,032	118	136
Repayments of intercompany investing activities	(1,068)	(4,114)	(746)
Reduction in investment in subsidiaries	1,288	3,600
Additional investment in subsidiaries	(718)	(4,600)	(598)
Net cash (used in)/from investing activities	526	(5,054)	(1,226)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	642	(237)	469
Senior notes issued	649	1,606
Proceeds from issuance of other debt	0	400	592
Debt issuance costs	(9)	(14)	(5)
Repayments of debt	(614)	(1,037)	(165)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	0
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	0	0	0
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	1,721	4,368	181
Repayments of intercompany financing activities	(2,245)	(30)	(472)
Net cash provided by (used in) financing activities	144	5,056	600
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	1	(2)	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	2	2
CASH AND CASH EQUIVALENTS, END OF PERIOD	1	0	2
Other | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	939	1,114	(222)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(292)	(221)	(128)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(4)	44
Other, net	(4)	20	16
Proceeds from intercompany investing activities	1,237	30	151
Repayments of intercompany investing activities	(1,722)	(769)	(181)
Reduction in investment in subsidiaries	618	0
Additional investment in subsidiaries	(153)	(3,600)	0
Net cash (used in)/from investing activities	(347)	(4,153)	(955)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	32	4	0
Debt issuance costs	0	0	0
Repayments of debt	(120)	(564)	(1)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	605
Payments for share cancellation related to legal settlement	(177)
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(151)	(90)	(150)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	1,069	4,266	828
Repayments of intercompany financing activities	(1,066)	(118)	(136)
Net cash provided by (used in) financing activities	(547)	3,397	1,124
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	45	358	(53)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	527	624
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 1,027	$ 870	$ 527

Financial Information for Is138

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Narrative (Details) € in Millions, $ in Millions	Dec. 31, 2017USD ($)	May 26, 2016USD ($)	May 26, 2016EUR (€)	Mar. 22, 2016USD ($)	Aug. 15, 2013USD ($)
Debt Instrument [Line Items]
Long-term debt	$ 5,638
Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 3,506
Trinity Acquisition plc
Debt Instrument [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	10000.00%
Trinity Acquisition plc | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 2,100
Debt Instrument, Face Amount		$ 609	€ 540	$ 1,000	$ 525

Financial Information for Is139

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Commissions and fees									$ 8,116	$ 7,778	$ 3,809
Interest and other income									86	109	20
Total revenues	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 1,927	$ 1,777	$ 1,949	$ 2,234	8,202	7,887	3,829
Costs of providing services
Salaries and benefits									4,745	4,646	2,303
Other operating expenses									1,534	1,551	718
Depreciation expense									203	178	95
Amortization									(581)	(591)	(76)
Restructuring costs									132	193	126
Integration expenses									(269)	(177)	(84)
Total costs of providing services	1,968	1,811	1,829	1,856	1,839	1,776	1,813	1,908	7,464	7,336	3,402
Income from operations	110	41	124	463	88	1	136	326	738	551	427
Income from Group undertakings									0	0	0
Expenses due to Group undertakings									0	0	0
Interest expense									188	184	142
Other (income)/expense, net									61	27	(55)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									489	340	340
Provision for income taxes									(100)	(96)	(33)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									589	436	373
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(11)
Equity account for subsidiaries									0	0	0
NET INCOME	253	(54)	41	352	148	(31)	76	245	592	438	384
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$ 245	$ (54)	$ 33	$ 344	$ 142	$ (32)	$ 72	$ 238	568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									976	(429)	403
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
Consolidating adjustments | Issuer
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									0	0	0
Depreciation expense									0	0	0
Amortization									3	0	0
Restructuring costs									0	0	0
Integration expenses									0	0	0
Total costs of providing services									(3)	0	0
Income from operations									3	0	0
Income from Group undertakings									911	928	577
Expenses due to Group undertakings									(911)	(928)	(577)
Interest expense									0	0	0
Other (income)/expense, net									238	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(235)	0	0
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									(1,343)	(863)	(1,219)
NET INCOME									(1,578)	(863)	(1,219)
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									(1,578)	(863)	(1,219)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									(2,629)	1,583	(1,316)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(2,629)	1,583	(1,316)
Willis Towers Watson | Reportable Legal Entities
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									4	2	1
Other operating expenses									3	3	8
Depreciation expense									0	0	0
Amortization									0	0	0
Restructuring costs									0	0	0
Integration expenses									0	(1)	(4)
Total costs of providing services									7	6	13
Income from operations									(7)	(6)	(13)
Income from Group undertakings									0	(3)	0
Expenses due to Group undertakings									0	3	0
Interest expense									30	32	43
Other (income)/expense, net									(35)	0	10
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Provision for income taxes									0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									(2)	(38)	(66)
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									570	458	439
NET INCOME									568	420	373
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									568	420	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									939	(427)	402
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									939	(427)	402
The Other Guarantors | Reportable Legal Entities
Revenues
Commissions and fees									19	19	11
Interest and other income									0	2	1
Total revenues									19	21	12
Costs of providing services
Salaries and benefits									48	16	77
Other operating expenses									111	200	101
Depreciation expense									6	19	22
Amortization									(3)	0	0
Restructuring costs									23	68	41
Integration expenses									(92)	(42)	(14)
Total costs of providing services									283	345	255
Income from operations									(264)	(324)	(243)
Income from Group undertakings									(614)	(657)	(374)
Expenses due to Group undertakings									230	228	200
Interest expense									34	38	41
Other (income)/expense, net										(2)	(42)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									86	69	(68)
Provision for income taxes									(24)	(125)	(51)
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									110	194	(17)
Interest in (loss)/earnings of associates, net of tax									0	0	(9)
Equity account for subsidiaries									483	254	443
NET INCOME									593	448	435
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									593	448	435
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									953	(379)	462
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									953	(379)	462
The Issuer | Reportable Legal Entities
Revenues
Commissions and fees									0	0	0
Interest and other income									0	0	0
Total revenues									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									1	0	0
Depreciation expense									0	0	0
Amortization									0	0	0
Restructuring costs									0	0	0
Integration expenses									0	0	0
Total costs of providing services									1	0	0
Income from operations									(1)	0	0
Income from Group undertakings									(149)	(132)	(93)
Expenses due to Group undertakings									26	26	26
Interest expense									103	90	40
Other (income)/expense, net										0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									19	16	27
Provision for income taxes									2	3	5
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									17	13	22
Interest in (loss)/earnings of associates, net of tax									0	0	0
Equity account for subsidiaries									290	151	337
NET INCOME									307	164	359
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									307	164	359
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									663	(656)	400
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									663	(656)	400
Other | Reportable Legal Entities
Revenues
Commissions and fees									8,097	7,759	3,798
Interest and other income									86	107	19
Total revenues									8,183	7,866	3,817
Costs of providing services
Salaries and benefits									4,693	4,628	2,225
Other operating expenses									1,419	1,348	609
Depreciation expense									197	159	73
Amortization									(581)	(591)	(76)
Restructuring costs									109	125	85
Integration expenses									(177)	(134)	(66)
Total costs of providing services									7,176	6,985	3,134
Income from operations									1,007	881	683
Income from Group undertakings									(148)	(136)	(110)
Expenses due to Group undertakings									655	671	351
Interest expense									21	24	18
Other (income)/expense, net									(142)	29	(23)
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES									621	293	447
Provision for income taxes									(78)	26	13
INCOME FROM CONTINUING OPERATIONS BEFORE INTEREST IN EARNINGS OF ASSOCIATES									699	267	434
Interest in (loss)/earnings of associates, net of tax									(3)	(2)	(2)
Equity account for subsidiaries									0	0	0
NET INCOME									702	269	436
Income attributable to non-controlling interests									(24)	(18)	(11)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									678	251	425
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest									1,050	(550)	455
Comprehensive (income)/loss attributable to non-controlling interests									(37)	2	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									$ 1,013	$ (548)	$ 454

Financial Information for Is140

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Balance Sheet (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 1,030,000,000	$ 870,000,000	$ 532,000,000	$ 635,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,246,000,000	2,080,000,000
Prepaid and other current assets	430,000,000	337,000,000
Amounts due from group undertakings	0	0
Total current assets	15,861,000,000	13,792,000,000
Investments in subsidiaries	0	0
Fixed assets, net	985,000,000	839,000,000
Goodwill	10,519,000,000	10,413,000,000	3,737,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	447,000,000	353,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,597,000,000	16,461,000,000
TOTAL ASSETS	32,458,000,000	30,253,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,711,000,000	1,481,000,000
Short-term debt and current portion of long-term debt	85,000,000	508,000,000
Other current liabilities	804,000,000	876,000,000
Amounts due to group undertakings	0	0
Total current liabilities	14,755,000,000	13,370,000,000
Long-term debt	4,450,000,000	3,357,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	615,000,000	864,000,000
Provision for liabilities	558,000,000	575,000,000
Other non-current liabilities	544,000,000	532,000,000
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	7,426,000,000	6,649,000,000
TOTAL LIABILITIES	22,181,000,000	20,019,000,000
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,249,000,000	10,183,000,000	2,360,000,000	2,007,000,000
TOTAL LIABILITIES AND EQUITY	32,458,000,000	30,253,000,000
Consolidating adjustments | Issuer
ASSETS
Cash and cash equivalents	0	0	0	0
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	(149,000,000)	(62,000,000)
Amounts due from group undertakings	(14,055,000,000)	(12,043,000,000)
Total current assets	(14,204,000,000)	(12,105,000,000)
Investments in subsidiaries	(16,476,000,000)	(19,339,000,000)
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	(60,000,000)	(64,000,000)
Pension benefits assets	0	0
Other non-current assets	(90,000,000)	(47,000,000)
Non-current amounts due from group undertakings	(6,659,000,000)	(5,914,000,000)
Total non-current assets	(23,285,000,000)	(25,364,000,000)
TOTAL ASSETS	(37,489,000,000)	(37,469,000,000)
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	(49,000,000)
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	(152,000,000)	(5,000,000)
Amounts due to group undertakings	(14,055,000,000)	(12,043,000,000)
Total current liabilities	(14,207,000,000)	(12,097,000,000)
Long-term debt	0	0
Liability for pension benefits	0	0
Deferred tax liabilities	(89,000,000)	(149,000,000)
Provision for liabilities	0	0
Other non-current liabilities	0	(14,000,000)
Non-current amounts due to group undertakings	(6,659,000,000)	(5,914,000,000)
Total non-current liabilities	(6,748,000,000)	(6,077,000,000)
TOTAL LIABILITIES	(20,955,000,000)	(18,174,000,000)
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	(16,534,000,000)	(19,295,000,000)
Non-controlling interests	0	0
Total equity	(16,534,000,000)	(19,295,000,000)
TOTAL LIABILITIES AND EQUITY	(37,489,000,000)	(37,469,000,000)
Willis Towers Watson | Reportable Legal Entities
ASSETS
Cash and cash equivalents	2,000,000	0	3,000,000	9,000,000
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	0	0
Amounts due from group undertakings	6,202,000,000	7,229,000,000
Total current assets	6,204,000,000	7,229,000,000
Investments in subsidiaries	4,506,000,000	3,409,000,000
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Pension benefits assets	0	0
Other non-current assets	0	0
Non-current amounts due from group undertakings	0	0
Total non-current assets	4,506,000,000	3,409,000,000
TOTAL ASSETS	10,710,000,000	10,638,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	0
Short-term debt and current portion of long-term debt	0	0
Other current liabilities	87,000,000	77,000,000
Amounts due to group undertakings	0	0
Total current liabilities	87,000,000	77,000,000
Long-term debt	497,000,000	496,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	0	0
Other non-current liabilities	0	0
Non-current amounts due to group undertakings	0	0
Total non-current liabilities	497,000,000	496,000,000
TOTAL LIABILITIES	584,000,000	573,000,000
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	10,126,000,000	10,065,000,000
Non-controlling interests	0	0
Total equity	10,126,000,000	10,065,000,000
TOTAL LIABILITIES AND EQUITY	10,710,000,000	10,638,000,000
The Other Guarantors | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1,000,000	0	2,000,000	2,000,000
Fiduciary assets	0	0
Accounts receivable, net	4,000,000	7,000,000
Prepaid and other current assets	314,000,000	74,000,000
Amounts due from group undertakings	1,420,000,000	849,000,000
Total current assets	1,739,000,000	930,000,000
Investments in subsidiaries	10,052,000,000	8,621,000,000
Fixed assets, net	25,000,000	34,000,000
Goodwill	0	0
Other intangible assets, net	60,000,000	64,000,000
Pension benefits assets	0	0
Other non-current assets	146,000,000	90,000,000
Non-current amounts due from group undertakings	4,884,000,000	4,859,000,000
Total non-current assets	15,167,000,000	13,668,000,000
TOTAL ASSETS	16,906,000,000	14,598,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	26,000,000	41,000,000
Short-term debt and current portion of long-term debt	0	394,000,000
Other current liabilities	112,000,000	87,000,000
Amounts due to group undertakings	10,467,000,000	9,946,000,000
Total current liabilities	10,605,000,000	10,468,000,000
Long-term debt	986,000,000	186,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	120,000,000	120,000,000
Other non-current liabilities	24,000,000	63,000,000
Non-current amounts due to group undertakings	519,000,000	518,000,000
Total non-current liabilities	1,649,000,000	887,000,000
TOTAL LIABILITIES	12,254,000,000	11,355,000,000
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	4,652,000,000	3,243,000,000
Non-controlling interests	0	0
Total equity	4,652,000,000	3,243,000,000
TOTAL LIABILITIES AND EQUITY	16,906,000,000	14,598,000,000
The Issuer | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Fiduciary assets	0	0
Accounts receivable, net	0	0
Prepaid and other current assets	1,000,000	1,000,000
Amounts due from group undertakings	2,807,000,000	1,595,000,000
Total current assets	2,808,000,000	1,596,000,000
Investments in subsidiaries	1,918,000,000	7,309,000,000
Fixed assets, net	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Pension benefits assets	0	0
Other non-current assets	3,000,000	0
Non-current amounts due from group undertakings	1,775,000,000	1,055,000,000
Total non-current assets	3,696,000,000	8,364,000,000
TOTAL ASSETS	6,504,000,000	9,960,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	0	0
Deferred revenue and accrued expenses	0	1,000,000
Short-term debt and current portion of long-term debt	0	22,000,000
Other current liabilities	33,000,000	33,000,000
Amounts due to group undertakings	1,658,000,000	0
Total current liabilities	1,691,000,000	56,000,000
Long-term debt	2,883,000,000	2,506,000,000
Liability for pension benefits	0	0
Deferred tax liabilities	0	0
Provision for liabilities	0	0
Other non-current liabilities	0	0
Non-current amounts due to group undertakings	423,000,000	423,000,000
Total non-current liabilities	3,306,000,000	2,929,000,000
TOTAL LIABILITIES	4,997,000,000	2,985,000,000
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	0	0
Total Willis Towers Watson shareholders’ equity	1,507,000,000	6,975,000,000
Non-controlling interests	0	0
Total equity	1,507,000,000	6,975,000,000
TOTAL LIABILITIES AND EQUITY	6,504,000,000	9,960,000,000
Other | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1,027,000,000	870,000,000	$ 527,000,000	$ 624,000,000
Fiduciary assets	12,155,000,000	10,505,000,000
Accounts receivable, net	2,242,000,000	2,073,000,000
Prepaid and other current assets	264,000,000	324,000,000
Amounts due from group undertakings	3,626,000,000	2,370,000,000
Total current assets	19,314,000,000	16,142,000,000
Investments in subsidiaries	0	0
Fixed assets, net	960,000,000	805,000,000
Goodwill	10,519,000,000	10,413,000,000
Other intangible assets, net	3,882,000,000	4,368,000,000
Pension benefits assets	764,000,000	488,000,000
Other non-current assets	388,000,000	310,000,000
Non-current amounts due from group undertakings	0	0
Total non-current assets	16,513,000,000	16,384,000,000
TOTAL ASSETS	35,827,000,000	32,526,000,000
LIABILITIES AND EQUITY
Fiduciary liabilities	12,155,000,000	10,505,000,000
Deferred revenue and accrued expenses	1,685,000,000	1,488,000,000
Short-term debt and current portion of long-term debt	85,000,000	92,000,000
Other current liabilities	724,000,000	684,000,000
Amounts due to group undertakings	1,930,000,000	2,097,000,000
Total current liabilities	16,579,000,000	14,866,000,000
Long-term debt	84,000,000	169,000,000
Liability for pension benefits	1,259,000,000	1,321,000,000
Deferred tax liabilities	704,000,000	1,013,000,000
Provision for liabilities	438,000,000	455,000,000
Other non-current liabilities	520,000,000	483,000,000
Non-current amounts due to group undertakings	5,717,000,000	4,973,000,000
Total non-current liabilities	8,722,000,000	8,414,000,000
TOTAL LIABILITIES	25,301,000,000	23,280,000,000
EQUITY (i)
REDEEMABLE NON-CONTROLLING INTEREST	28,000,000	51,000,000
Total Willis Towers Watson shareholders’ equity	10,375,000,000	9,077,000,000
Non-controlling interests	123,000,000	118,000,000
Total equity	10,498,000,000	9,195,000,000
TOTAL LIABILITIES AND EQUITY	$ 35,827,000,000	$ 32,526,000,000

Financial Information for Is141

Financial Information for Issuer, Parent Guarantor, Other Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$ 862	$ 933	$ 244
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(300)	(218)	(146)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(1)	44
Other, net	(4)	23	16
Proceeds from intercompany investing activities	0	0	0
Repayments of intercompany investing activities	0	0	0
Reduction in investment in subsidiaries	0	0
Additional investment in subsidiaries	0	0	0
Net cash (used in)/from investing activities	(335)	195	(943)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	642	(237)	469
Senior notes issued	649	1,606	0
Proceeds from issuance of other debt	32	404	592
Debt issuance costs	(9)	(14)	(5)
Repayments of debt	(734)	(1,901)	(166)
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	131
Payments for share cancellation related to legal settlement	(177)	0	0
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)	0
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(479)	(775)	640
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	48	353	(59)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	532	635
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,030	870	532
Consolidating adjustments | Issuer
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(209)	(621)	(150)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	94	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	3	0
Other, net	0	(30)	0
Proceeds from intercompany investing activities	(3,630)	(193)	(608)
Repayments of intercompany investing activities	4,471	8,635	1,009
Reduction in investment in subsidiaries	(2,010)	(8,200)
Additional investment in subsidiaries	2,010	8,200	598
Net cash (used in)/from investing activities	841	8,509	999
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	0	0
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	(598)
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	209	554	150
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	(4,471)	(8,635)	(1,009)
Repayments of intercompany financing activities	3,630	193	608
Net cash provided by (used in) financing activities	(632)	(7,888)	(849)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Consolidating adjustments | Parent Issuer
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(151)	(157)	(150)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	94	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	3	0
Other, net	0	(30)	0
Proceeds from intercompany investing activities	(3,311)	(148)	(608)
Repayments of intercompany investing activities	2,790	8,634	1,009
Reduction in investment in subsidiaries	(2,010)	(8,200)
Additional investment in subsidiaries	2,010	8,200	598
Net cash (used in)/from investing activities	(521)	8,553	999
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	0	0
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	(598)
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	151	90	150
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	(2,790)	(8,634)	(1,009)
Repayments of intercompany financing activities	3,311	148	608
Net cash provided by (used in) financing activities	672	(8,396)	(849)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Willis Towers Watson | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	743	(20)	(10)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	0	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	0	0
Proceeds from intercompany investing activities	1,042	0	321
Repayments of intercompany investing activities	0	(3,751)	(82)
Reduction in investment in subsidiaries	104	4,600
Additional investment in subsidiaries	(1,139)	0	0
Net cash (used in)/from investing activities	7	849	239
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	0	0	0
Repayments of debt	0	(300)	0
Repurchase of shares	(532)	(396)	(82)
Proceeds from issuance of shares	61	63	124
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	(277)	(199)	(277)
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	0	0	0
Repayments of intercompany financing activities	0	0	0
Net cash provided by (used in) financing activities	(748)	(832)	(235)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	2	(3)	(6)
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	3	9
CASH AND CASH EQUIVALENTS, END OF PERIOD	2	0	3
The Other Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	(640)	308	593
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(8)	(91)	(18)
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	33	0
Proceeds from intercompany investing activities	275	108	136
Repayments of intercompany investing activities	(73)	(3,513)	0
Reduction in investment in subsidiaries	1,288	3,600
Additional investment in subsidiaries	(570)	(4,600)	(420)
Net cash (used in)/from investing activities	912	(4,463)	(302)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	155	0	0
Senior notes issued	649	0
Proceeds from issuance of other debt	0	0	0
Debt issuance costs	(5)	0	0
Repayments of debt	(394)	0	(149)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	0
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	(58)	(162)	0
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	1,920	4,368	181
Repayments of intercompany financing activities	(2,538)	(53)	(323)
Net cash provided by (used in) financing activities	(271)	4,153	(291)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	1	(2)	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	2	2
CASH AND CASH EQUIVALENTS, END OF PERIOD	1	0	2
The Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	29	152	33
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	0	0	0
Capitalized software costs	0	0
Acquisitions of operations, net of cash acquired	0	0	0
Net disposals of operations	0	0	0
Other, net	0	0	0
Proceeds from intercompany investing activities	1,076	55	0
Repayments of intercompany investing activities	(2,676)	(602)	(746)
Reduction in investment in subsidiaries	0	0
Additional investment in subsidiaries	(148)	0	(178)
Net cash (used in)/from investing activities	(1,748)	(547)	(924)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	487	(237)	469
Senior notes issued	0	1,606
Proceeds from issuance of other debt	0	400	592
Debt issuance costs	(4)	(14)	(5)
Repayments of debt	(220)	(1,037)	(16)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	0
Payments for share cancellation related to legal settlement	0
Payments of deferred and contingent consideration related to acquisitions	0	0
Cash paid for employee taxes on withholding shares	0	0	0
Dividends paid	0	(302)	0
Acquisitions of and dividends paid to non-controlling interests	0	0	0
Proceeds from intercompany financing activities	1,482	1	0
Repayments of intercompany financing activities	(26)	(22)	(149)
Net cash provided by (used in) financing activities	1,719	395	891
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS, END OF PERIOD	0	0	0
Other | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	939	1,114	(222)
CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES
Additions to fixed assets and software for internal use	(292)	(221)	(128)
Capitalized software costs	(75)	(85)
Acquisitions of operations, net of cash acquired	(13)	476	(857)
Net disposals of operations	57	(4)	44
Other, net	(4)	20	16
Proceeds from intercompany investing activities	1,237	30	151
Repayments of intercompany investing activities	(1,722)	(769)	(181)
Reduction in investment in subsidiaries	618	0
Additional investment in subsidiaries	(153)	(3,600)	0
Net cash (used in)/from investing activities	(347)	(4,153)	(955)
CASH FLOWS FROM FINANCING ACTIVITIES
Net borrowings/(payments) on revolving credit facility	0	0	0
Senior notes issued	0	0
Proceeds from issuance of other debt	32	4	0
Debt issuance costs	0	0	0
Repayments of debt	(120)	(564)	(1)
Repurchase of shares	0	0	0
Proceeds from issuance of shares	0	0	605
Payments for share cancellation related to legal settlement	(177)
Payments of deferred and contingent consideration related to acquisitions	(65)	(67)
Cash paid for employee taxes on withholding shares	(18)	(13)	(1)
Dividends paid	(151)	(90)	(150)
Acquisitions of and dividends paid to non-controlling interests	(51)	(21)	(21)
Proceeds from intercompany financing activities	1,069	4,266	828
Repayments of intercompany financing activities	(1,066)	(118)	(136)
Net cash provided by (used in) financing activities	(547)	3,397	1,124
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	45	358	(53)
Effect of exchange rate changes on cash and cash equivalents	112	(15)	(44)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	870	527	624
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 1,027	$ 870	$ 527