10-Q

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

_____________________________________________ 

FORM 10-Q

_____________________________________________ 

Quarterly Report Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

For the quarterly period ended September 30, 2017

_____________________________________________ 

Marsh & McLennan Companies, Inc.

1166 Avenue of the Americas

New York, New York 10036

(212) 345-5000

_____________________________________________ 

Commission file number 1-5998

State of Incorporation: Delaware

I.R.S. Employer Identification No. 36-2668272

_____________________________________________ 

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ý    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ý    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large Accelerated Filer  x	Accelerated Filer  ¨
Non-Accelerated Filer  ¨(Do not check if a smaller reporting company)	Smaller Reporting Company  ¨
	Emerging Growth Company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).     Yes  ¨    No  ý

As of October 25, 2017, there were outstanding 510,356,826 shares of common stock, par value $1.00 per share, of the registrant.

INFORMATION CONCERNING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q contains "forward-looking statements," as defined in the Private Securities Litigation Reform Act of 1995. These statements, which express management's current views concerning future events or results, use words like "anticipate," "assume," "believe," "continue," "estimate," "expect," "intend," "plan," "project" and similar terms, and future or conditional tense verbs like "could," "may," "might," "should," "will" and "would." Forward-looking statements are subject to inherent risks and uncertainties that could cause actual results to differ materially from those expressed or implied in our forward-looking statements.

Factors that could materially affect our future results include, among other things: (1) the impact of any investigations, reviews or other activity by regulatory or law enforcement authorities, including the European Commission’s investigation into the aviation insurance and reinsurance sector; (2) the impact from lawsuits, other contingent liabilities and loss contingencies arising from errors and omissions, breach of fiduciary duty or other claims against us; (3) our ability to compete effectively and adapt to changes in the competitive environment, including to respond to disintermediation, pricing pressures and technological and other types of innovation; (4) our exposure to potential civil damages, criminal penalties or other consequences, such as reputational impact, if we fail to comply with applicable U.S. and non-U.S. laws and regulations; (5) our organization's ability to maintain adequate safeguards to protect the security of our information systems and confidential, personal or proprietary information, particularly given the volume of our vendor network and the need to patch software vulnerabilities; (6) our ability to successfully recover if we experience a business continuity problem due to cyberattack, natural disaster or otherwise; (7) the impact of macroeconomic, political, regulatory or market conditions on us, our clients and the industries in which we operate; (8) the financial and operational impact of complying with laws and regulations where we operate, including the E.U.’s General Data Protection Regulation; (9) our ability to attract and retain key employees; (10) the impact on our competitive position of our tax rate relative to our competitors; (11) the impact of fluctuations in foreign exchange, interest rates and securities markets on our results; (12) the effect of our global pension obligations on our financial position, earnings and cash flows and the impact of low interest rates on those obligations; and (13) the impact of changes in accounting rules or in our accounting estimates or assumptions, including the impact of the adoption of the new revenue recognition standard.

The factors identified above are not exhaustive. We caution readers not to place undue reliance on any forward-looking statements, which are based only on information currently available to us and speak only as of the dates on which they are made. The Company undertakes no obligation to update or revise any forward-looking statement to reflect events or circumstances arising after the date on which it is made.

Further information concerning Marsh & McLennan Companies and its businesses, including information about factors that could materially affect our results of operations and financial condition, is contained in the Company's filings with the Securities and Exchange Commission, including the "Risk Factors" section and in the "Management’s Discussion and Analysis of Financial Condition and Results of Operations" section of our most recently filed Annual Report on Form 10-K.

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TABLE OF CONTENTS

PART I. FINANCIAL INFORMATION		4
ITEM 1.	FINANCIAL STATEMENTS (UNAUDITED)	4
	CONSOLIDATED STATEMENTS OF INCOME	4
	CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	5
	CONSOLIDATED BALANCE SHEETS	6
	CONSOLIDATED BALANCE SHEETS (Continued)	7
	CONSOLIDATED STATEMENTS OF CASH FLOWS	8
	CONSOLIDATED STATEMENTS OF EQUITY	9
	NOTES TO CONSOLIDATED FINANCIAL STATEMENTS	10
ITEM 2.	MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS	32
	OF OPERATIONS
ITEM 3.	QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK	43
ITEM 4.	CONTROLS & PROCEDURES	45
PART II. OTHER INFORMATION		46
ITEM 1.	LEGAL PROCEEDINGS	46
ITEM 1A.	RISK FACTORS	46
ITEM 2.	UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS	46
ITEM 3.	DEFAULTS UPON SENIOR SECURITIES	47
ITEM 4.	MINE SAFETY DISCLOSURE	47
ITEM 5.	OTHER INFORMATION	47
ITEM 6.	EXHIBITS	47

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PART I.    FINANCIAL INFORMATION

Item 1. Financial Statements.

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF INCOME

(Unaudited)

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions, except per share amounts)	2017			2016			2017			2016
Revenue	$	3,341		$	3,135		$	10,339		$	9,847
Expense:
Compensation and benefits	1,906			1,817			5,786			5,543
Other operating expenses	838			746			2,383			2,273
Operating expenses	2,744			2,563			8,169			7,816
Operating income	597			572			2,170			2,031
Interest income	2			—			6			4
Interest expense	(60		)	(47		)	(178		)	(141		)
Investment (loss) income	(2		)	—			3			(2		)
Income before income taxes	537			525			2,001			1,892
Income tax expense	140			141			519			538
Net income before non-controlling interests	397			384			1,482			1,354
Less: Net income attributable to non-controlling interests	4			5			19			22
Net income attributable to the Company	$	393		$	379		$	1,463		$	1,332
Net income Per Share Attributable to the Company:
Basic	$	0.77		$	0.73		$	2.85		$	2.56
Diluted	$	0.76		$	0.73		$	2.81		$	2.54
Average number of shares outstanding:
Basic	512			518			514			520
Diluted	519			523			520			525
Shares outstanding at September 30,	511			516			511			516

The accompanying notes are an integral part of these unaudited consolidated statements.

4

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Net income before non-controlling interests	$	397		$	384		$	1,482		$	1,354
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	127			(52		)	652			(373		)
Unrealized investment (losses) gains	(8		)	1			11			1
(Loss) gain related to pension/post-retirement plans	(168		)	82			(140		)	383
Other comprehensive (loss) income, before tax	(49		)	31			523			11
Income tax (credit) expense on other comprehensive income	(30		)	19			(10		)	80
Other comprehensive (loss) income, net of tax	(19		)	12			533			(69		)
Comprehensive income	378			396			2,015			1,285
Less: comprehensive income attributable to non-controlling interest	4			5			19			22
Comprehensive income attributable to the Company	$	374		$	391		$	1,996		$	1,263

The accompanying notes are an integral part of these unaudited consolidated statements.

5

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(In millions, except share amounts)	(Unaudited) September 30, 2017			December 31, 2016
ASSETS
Current assets:
Cash and cash equivalents	$	1,078		$	1,026
Receivables
Commissions and fees	3,651			3,370
Advanced premiums and claims	52			83
Other	311			286
	4,014			3,739
Less-allowance for doubtful accounts and cancellations	(105		)	(96		)
Net receivables	3,909			3,643
Other current assets	228			215
Total current assets	5,215			4,884
Goodwill	9,100			8,369
Other intangible assets	1,320			1,126
Fixed assets (net of accumulated depreciation and amortization of $1,822 at September 30, 2017 and $1,683 at December 31, 2016)	728			725
Pension related assets	1,155			776
Deferred tax assets	947			1,097
Other assets	1,225			1,213
	$	19,690		$	18,190

The accompanying notes are an integral part of these unaudited consolidated statements.

6

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS (Continued)

(In millions, except share amounts)	(Unaudited) September 30, 2017			December 31, 2016
LIABILITIES AND EQUITY
Current liabilities:
Short-term debt	$	13		$	312
Accounts payable and accrued liabilities	2,002			1,969
Accrued compensation and employee benefits	1,377			1,655
Accrued income taxes	229			146
Dividends payable	193			—
Total current liabilities	3,814			4,082
Fiduciary liabilities	5,128			4,241
Less – cash and investments held in a fiduciary capacity	(5,128		)	(4,241		)
	—			—
Long-term debt	5,475			4,495
Pension, post-retirement and post-employment benefits	1,948			2,076
Liabilities for errors and omissions	316			308
Other liabilities	1,006			957
Commitments and contingencies	—			—
Equity:
Preferred stock, $1 par value, authorized 6,000,000 shares, none issued	—			—
Common stock, $1 par value, authorized
1,600,000,000 shares, issued 560,641,640 shares at September 30, 2017
and December 31, 2016	561			561
Additional paid-in capital	783			842
Retained earnings	13,113			12,388
Accumulated other comprehensive loss	(4,560		)	(5,093		)
Non-controlling interests	85			80
	9,982			8,778
Less – treasury shares, at cost, 49,484,693 shares at September 30, 2017
and 46,150,415 shares at December 31, 2016	(2,851		)	(2,506		)
Total equity	7,131			6,272
	$	19,690		$	18,190

The accompanying notes are an integral part of these unaudited consolidated statements.

7

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

For the Nine Months Ended September 30,
(In millions)	2017			2016
Operating cash flows:
Net income before non-controlling interests	$	1,482		$	1,354
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization of fixed assets and capitalized software	234			231
Amortization of intangible assets	122			99
Adjustments and payments related to contingent consideration liability	(30		)	(37		)
Gain on deconsolidation of subsidiary	—			(12		)
Provision for deferred income taxes	52			43
(Gain) loss on investments	(3		)	2
Loss on disposition of assets	9			3
Share-based compensation expense	111			84
Changes in assets and liabilities:
Net receivables	(248		)	(162		)
Other current assets	(14		)	(20		)
Other assets	(18		)	(2		)
Accounts payable and accrued liabilities	11			(29		)
Accrued compensation and employee benefits	(278		)	(349		)
Accrued income taxes	77			65
Contributions to pension and other benefit plans in excess of current year expense/credit	(337		)	(214		)
Other liabilities	83			(3		)
Effect of exchange rate changes	(116		)	59
Net cash provided by operations	1,137			1,112
Financing cash flows:
Purchase of treasury shares	(600		)	(625		)
Proceeds from debt	987			347
Repayments of debt	(313		)	(9		)
Shares withheld for taxes on vested units – treasury shares	(49		)	(38		)
Issuance of common stock from treasury shares	134			154
Payments of deferred and contingent consideration for acquisitions	(127		)	(96		)
Distributions of non-controlling interests	(14		)	(12		)
Dividends paid	(545		)	(504		)
Net cash used for financing activities	(527		)	(783		)
Investing cash flows:
Capital expenditures	(217		)	(174		)
Net sales (purchases) of long-term investments	(21		)	(4		)
Proceeds from sales of fixed assets	4			5
Acquisitions	(629		)	(88		)
Other, net	4			3
Net cash used for investing activities	(859		)	(258		)
Effect of exchange rate changes on cash and cash equivalents	301			(57		)
Increase in cash and cash equivalents	52			14
Cash and cash equivalents at beginning of period	1,026			1,374
Cash and cash equivalents at end of period	$	1,078		$	1,388

The accompanying notes are an integral part of these unaudited consolidated statements.

8

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF EQUITY

(Unaudited)

For the Nine Months Ended September 30,
(In millions, except per share amounts)	2017			2016
COMMON STOCK
Balance, beginning and end of period	$	561		$	561
ADDITIONAL PAID-IN CAPITAL
Balance, beginning of year	$	842		$	861
Change in accrued stock compensation costs	26			14
Issuance of shares under stock compensation plans and employee stock purchase plans and related tax impact in 2016	(82		)	(63		)
Other	(3		)	—
Balance, end of period	$	783		$	812
RETAINED EARNINGS
Balance, beginning of year	$	12,388		$	11,302
Net income attributable to the Company	1,463			1,332
Dividend equivalents declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)	(4		)	(5		)
Dividends declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)	(734		)	(676		)
Balance, end of period	$	13,113		$	11,953
ACCUMULATED OTHER COMPREHENSIVE LOSS
Balance, beginning of year	$	(5,093	)	$	(4,220	)
Other comprehensive income (loss), net of tax	533			(69		)
Balance, end of period	$	(4,560	)	$	(4,289	)
TREASURY SHARES
Balance, beginning of year	$	(2,506	)	$	(1,991	)
Issuance of shares under stock compensation plans and employee stock purchase plans	255			250
Purchase of treasury shares	(600		)	(625		)
Balance, end of period	$	(2,851	)	$	(2,366	)
NON-CONTROLLING INTERESTS
Balance, beginning of year	$	80		$	89
Net income attributable to non-controlling interests	19			22
Deconsolidation of subsidiary	—			(14		)
Distributions and other changes	(14		)	(14		)
Balance, end of period	$	85		$	83
TOTAL EQUITY	$	7,131		$	6,754

The accompanying notes are an integral part of these unaudited consolidated statements.

9

MARSH & McLENNAN COMPANIES, INC. AND SUBSIDIARIES

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(Unaudited)

1.     Nature of Operations

Marsh & McLennan Companies, Inc. and its consolidated subsidiaries (the "Company"), a global professional services firm, is organized based on the different services that it offers. Under this structure, the Company’s two segments are Risk and Insurance Services and Consulting.

The Risk and Insurance Services segment provides risk management services and insurance broking, reinsurance broking and insurance program management services for businesses, public entities, insurance companies, associations, professional services organizations and private clients. The Company conducts business in this segment through Marsh and Guy Carpenter.

The Company conducts business in its Consulting segment through Mercer and Oliver Wyman Group. Mercer provides consulting expertise, advice, services and solutions in the areas of health, wealth and career. As of September 30, 2017, Mercer had assets under delegated management of approximately $210 billion worldwide. Oliver Wyman Group provides specialized management and economic and brand consulting services.

Acquisitions impacting the Risk and Insurance Services and Consulting segments are discussed in Note 7 to the consolidated financial statements.

2.     Principles of Consolidation and Other Matters

The consolidated financial statements included herein have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission. While certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been omitted pursuant to such rules and regulations for interim filings, the Company believes that the information and disclosures presented are adequate to make such information and disclosures not misleading. These consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 (the "2016 Form 10-K").

The financial information contained herein reflects all normal recurring adjustments which are, in the opinion of management, necessary for a fair presentation of the Company’s consolidated financial statements as of and for the three and nine month periods ended September 30, 2017 and 2016.

Cash and Cash Equivalents

Cash and cash equivalents primarily consist of certificates of deposit and time deposits, with original maturities of three months or less, and money market funds. The estimated fair value of the Company's cash and cash equivalents approximates their carrying value. The Company is required to maintain operating funds of approximately $184 million, primarily related to regulatory requirements outside the United States or as collateral under captive insurance arrangements.

Investments

The Company holds investments in certain private equity funds. Investments in private equity funds are accounted for under the equity method of accounting using a consistently applied three-month lag period adjusted for any known significant changes from the lag period to the reporting date of the Company. The underlying private equity funds follow investment company accounting, where investments within the fund are carried at fair value. Investment gains or losses for the Company's proportionate share of the change in fair value of the funds are recorded in earnings. Investments accounted for using the equity method of accounting are included in other assets in the consolidated balance sheets.

The caption "Investment income (loss)" in the consolidated statements of income comprises realized and unrealized gains and losses from investments recognized in earnings. It includes, when applicable, other than temporary declines in the value of debt and available-for-sale securities and equity method gains or losses on the Company's investments in private equity funds. The Company recorded a net investment loss of $2 million in the third quarter of 2017 compared to a net investment gain of less than $1 million for the same period in 2016, and net investment income of $3 million compared to a net investment loss of $2 million for the nine months ended September 30, 2017 and 2016, respectively.

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Income Taxes

The Company's effective tax rate in the third quarter of 2017 was 26.2% compared with 26.8% in the third quarter of 2016. The effective tax rate for the first nine months of 2017 and 2016 was 25.9% and 28.4%, respectively. The rates reflect foreign operations which are taxed at rates below the U.S. statutory tax rate, including the effect of repatriation, as well as the impact of discrete tax matters such as tax legislation, changes in valuation allowances, nontaxable adjustments to contingent acquisition consideration and, starting in 2017, excess tax benefits related to share-based compensation.

The Company is routinely examined by tax authorities in the jurisdictions in which it has significant operations. The Company regularly considers the likelihood of assessments in each of the taxing jurisdictions resulting from examinations. When evaluating the potential imposition of penalties, the Company considers a number of relevant factors under penalty statutes, including appropriate disclosure of the tax return position, the existence of legal authority supporting the Company's position, and reliance on the opinion of professional tax advisors.

The Company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in tax returns. The Company's gross unrecognized tax benefits decreased from $65 million at December 31, 2016 to $64 million at September 30, 2017 due to settlements of audits and expirations of statutes of limitation, partially offset by current accruals. It is reasonably possible that the total amount of unrecognized tax benefits will decrease between zero and approximately $9 million within the next twelve months due to settlements of audits and expirations of statutes of limitation.

3.     Fiduciary Assets and Liabilities

In its capacity as an insurance broker or agent, the Company collects premiums from insureds and, after deducting its commissions, remits the premiums to the respective insurance underwriters. The Company also collects claims or refunds from underwriters on behalf of insureds. Unremitted insurance premiums and claims proceeds are held by the Company in a fiduciary capacity. Risk and Insurance Services revenue includes interest on fiduciary funds of $11 million and $8 million for the three months ended September 30, 2017 and 2016, respectively, and $28 million and $20 million for the nine months ended September 30, 2017 and 2016, respectively. The Consulting segment recorded fiduciary interest income of $2 million and $1 million for each of the three month periods ended September 30, 2017 and 2016, respectively, and $3 million and $2 million for the nine months ended September 30, 2017 and 2016, respectively. Since fiduciary assets are not available for corporate use, they are shown in the consolidated balance sheets as an offset to fiduciary liabilities.

Net uncollected premiums and claims and the related payables amounted to $6.8 billion at September 30, 2017 and $7.0 billion atDecember 31, 2016. The Company is not a principal to the contracts under which the right to receive premiums or the right to receive reimbursement of insured losses arises. Accordingly, net uncollected premiums and claims and the related payables are not assets and liabilities of the Company and are not included in the accompanying consolidated balance sheets.

In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. These advances are made from corporate funds and are reflected in the accompanying consolidated balance sheets as receivables.

4.    Per Share Data

Basic net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock.

Diluted net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock, which have been adjusted for the dilutive effect of potentially issuable common shares.

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Basic and Diluted EPS Calculation	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share amounts)	2017		2016		2017		2016
Net income before non-controlling interests	$	397	$	384	$	1,482	$	1,354
Less: Net income attributable to non-controlling interests	4		5		19		22
Net income attributable to the Company	$	393	$	379	$	1,463	$	1,332
Basic weighted average common shares outstanding	512		518		514		520
Dilutive effect of potentially issuable common shares	7		5		6		5
Diluted weighted average common shares outstanding	519		523		520		525
Average stock price used to calculate common stock equivalents	$	79.35	$	66.98	$	75.36	$	62.33

There were 11.3 million and 13.6 million stock options outstanding as of September 30, 2017 and 2016, respectively.

5.    Supplemental Disclosures to the Consolidated Statements of Cash Flows

The following schedule provides additional information concerning acquisitions, interest and income taxes paid for the nine-month periods ended September 30, 2017 and 2016.

(In millions)	2017			2016
Assets acquired, excluding cash	$	852		$	121
Liabilities assumed	(129		)	(4		)
Contingent/deferred purchase consideration	(94		)	(29		)
Net cash outflow for current year acquisitions	$	629		$	88

(In millions)	2017		2016
Interest paid	$	174	$	148
Income taxes paid, net of refunds	$	406	$	417

The classification of contingent consideration in the statement of cash flows is determined by whether the payment was part of the initial liability established on the acquisition date (financing) or an adjustment to the acquisition date liability (operating).

The following amounts are included in the consolidated statements of cash flows as a financing activity. The Company paid deferred and contingent consideration of $127 million for the nine months ended September 30, 2017. This consisted of deferred purchase consideration related to prior years' acquisitions of $47 million and contingent consideration of $80 million. For the nine months ended September 30, 2016, the Company paid deferred and contingent consideration of $96 million, consisting of deferred purchase consideration related to prior years' acquisitions of $53 million and contingent consideration of $43 million.

The following amounts are included in the operating section of the consolidated statements of cash flows. For the nine months ended September 30, 2017, the Company recorded a net credit for adjustments to acquisition related accounts of $3 million and made contingent consideration payments of $27 million. For the nine months ended September 30, 2016, the Company recorded a net charge for adjustments related to acquisition related accounts of $5 million and made contingent consideration payments of $42 million.

The Company had non-cash issuances of common stock under its share-based payment plan of $88 million and $71 million for the nine months ended September 30, 2017 and 2016, respectively. The Company recorded stock-based compensation expense for equity awards related to restricted stock units, performance stock units and stock options of $111 million and $84 million for the nine-month periods ended September 30, 2017 and 2016, respectively.

Effective January 1, 2017, the Company adopted new accounting guidance related to share-based compensation, that requires companies to record excess tax benefits and tax deficiencies as an income tax benefit or expense in the income statement and classify excess tax benefits as an operating activity in the statement of cash flows. Prior to the adoption of this standard, the Company recorded excess tax benefits in equity in the consolidated balance sheet and as a financing activity in the consolidated statement of cash flows. For the nine months ended September 30, 2017, the adoption of this new standard reduced income tax expense in the consolidated statement of income by approximately $58 million. For the nine months ended September 30, 2016, the Company recorded an

12

excess tax benefit of $30 million as an increase to equity in its consolidated balance sheet, which was reflected as cash provided by financing activities in the consolidated statement of cash flows.

6.    Other Comprehensive Income (Loss)

The changes, net of tax, in the balances of each component of Accumulated Other Comprehensive Income ("AOCI") for the three and nine-month periods ended September 30, 2017 and 2016, including amounts reclassified out of AOCI, are as follows:

(In millions)	Unrealized Investment Gains (Losses)			Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2017	$	30		$	(3,215	)	$	(1,356	)	$	(4,541	)
Other comprehensive (loss) income before reclassifications	(5		)	(173		)	126			(52		)
Amounts reclassified from accumulated other comprehensive income	—			33			—			33
Net current period other comprehensive (loss) income	(5		)	(140		)	126			(19		)
Balance as of September 30, 2017	$	25		$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2016	$	6	$	(2,885	)	$	(1,422	)	$	(4,301	)
Other comprehensive income (loss) before reclassifications	1		36			(54		)	(17		)
Amounts reclassified from accumulated other comprehensive income	—		29			—			29
Net current period other comprehensive income (loss)	1		65			(54		)	12
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2017	$	19	$	(3,232	)	$	(1,880	)	$	(5,093	)
Other comprehensive income (loss) before reclassifications	6		(219		)	650			437
Amounts reclassified from accumulated other comprehensive income	—		96			—			96
Net current period other comprehensive income (loss)	6		(123		)	650			533
Balance as of September 30, 2017	$	25	$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2016	$	6	$	(3,124	)	$	(1,102	)	$	(4,220	)
Other comprehensive income (loss) before reclassifications	1		214			(374		)	(159		)
Amounts reclassified from accumulated other comprehensive income	—		90			—			90
Net current period other comprehensive income (loss)	1		304			(374		)	(69		)
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

13

The components of other comprehensive income (loss) for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

Three Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	127		$	1		$	126		$	(52	)	$	2	$	(54	)
Unrealized investment (losses) gains	(8		)	(3		)	(5		)	1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			1			1		—
Net actuarial losses (a)	43			10			33			41			12		29
Subtotal	43			10			33			42			13		29
Effect of remeasurement	3			—			3			—			—		—
Effect of settlement	1			—			1			—			—		—
Foreign currency translation (losses) gains	(215		)	(38		)	(177		)	40			4		36
Pension/post-retirement plans (losses) gains	(168		)	(28		)	(140		)	82			17		65
Other comprehensive (loss) income	$	(49	)	$	(30	)	$	(19	)	$	31		$	19	$	12
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Income tax credits on prior service cost and net actuarial losses are included in income tax expense.

Nine Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	652		$	2		$	650		$	(373	)	$	1	$	(374	)
Unrealized investment gains	11			5			6			1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			2			1		1
Net actuarial losses (a)	125			29			96			125			36		89
Subtotal	125			29			96			127			37		90
Effect of remeasurement	12			3			9			(1		)	—		(1		)
Effect of curtailment	(1		)	—			(1		)	3			1		2
Effect of settlement	2			—			2			1			—		1
Foreign currency translation (losses) gains	(277		)	(49		)	(228		)	253			41		212
Other	(1		)	—			(1		)	—			—		—
Pension/post-retirement plans (losses) gains	(140		)	(17		)	(123		)	383			79		304
Other comprehensive income (loss)	$	523		$	(10	)	$	533		$	11		$	80	$	(69	)
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Tax on prior service cost and net actuarial losses is included in income tax expense.

7.     Acquisitions

The Company has continued its strategy to grow its businesses and build shareholder value through strategic acquisitions. The Company’s acquisitions have been accounted for as business combinations. Net assets and results of operations are included in the Company’s consolidated financial statements commencing at the respective purchase closing dates. In connection with acquisitions, the Company records the estimated value of the net tangible assets purchased and the value of the identifiable intangible assets purchased, which typically consist of purchased customer lists, developed technology, trademarks and non-compete agreements. The valuation of purchased intangible assets involves significant estimates and assumptions. Until final valuations are complete, any change in assumptions could affect the carrying value of tangible assets, goodwill and identifiable intangible assets.

14

The Risk and Insurance Services segment completed seven acquisitions during the first nine months of 2017.

• January – Marsh & McLennan Agency ("MMA") acquired J. Smith Lanier & Co. ("JSL"), a privately held insurance brokerage firm providing insurance, risk management, and employee benefits solutions to businesses and individuals throughout the U.S.

• February – MMA acquired iaConsulting Services, a Texas-based employee benefits consulting firm.

• March – MMA acquired Blakestad, Inc., a Minnesota-based private client and commercial lines insurance agency, and RJF Financial Services, a Minnesota-based retirement advisory firm.

• May – MMA acquired Insurance Partners of Texas, a Texas-based employee benefits consulting firm.

• August – Marsh acquired International Catastrophe Insurance Managers, LLC, a Colorado-based property and casualty insurance agent, and MMA acquired Hendrick & Hendrick, Inc., a Texas-based insurance agency.

The Consulting segment completed one acquisition during the first nine months of 2017.

• August – Mercer acquired Jaeson Associates, a Portugal-based talent management consulting organization.

Total purchase consideration for acquisitions made during the nine months ended September 30, 2017 was $734 million, which consisted of cash paid of $640 million and deferred purchase and estimated contingent consideration of $94 million. Contingent consideration arrangements are based primarily on earnings before interest, tax, depreciation and amortization ("EBITDA") or revenue targets over a period of two to four years. The fair value of the contingent consideration was based on projected revenue or EBITDA of the acquired entities. Estimated fair values of assets acquired and liabilities assumed are subject to adjustment when purchase accounting is finalized. The Company also paid $47 million of deferred purchase consideration and $107 million of contingent consideration related to acquisitions made in prior years.

The following table presents the preliminary allocation of the acquisition cost to the assets acquired and liabilities assumed during 2017 based on their fair values:

For the Nine Months Ended September 30, 2017
(In millions)
Cash	$	640
Estimated fair value of deferred/contingent consideration	94
Total Consideration	$	734
Allocation of purchase price:
Cash and cash equivalents	$	11
Accounts receivable, net	17
Property, plant, and equipment	7
Other intangible assets	293
Goodwill	533
Other assets	2
Total assets acquired	863
Current liabilities	21
Other liabilities	108
Total liabilities assumed	129
Net assets acquired	$	734

The following chart provides information about other intangible assets acquired during 2017:

	Amount		Weighted Average Amortization Period
Client relationships	$	252	12 years
Other	41		5 years
	$	293

15

Prior-Year Acquisitions

The Risk and Insurance Services segment completed nine acquisitions during 2016.

• February – MMA acquired The Celedinas Agency, Inc., a Florida-based brokerage firm, providing property, casualty and marine insurance, as well as employee benefits services, and Aviation Solutions, LLC, a Missouri-based aviation risk advisor and insurance broker.

• March – MMA acquired Corporate Consulting Services, Ltd., a New York-based insurance brokerage and human resource consulting firm.

• August – MMA acquired Benefits Advisory Group LLC, an Atlanta-based employee benefits consulting firm.

• September – MMA acquired Vero Insurance, Inc., a Florida-based agency specializing in private client insurance services.

• November – MMA acquired Benefits Resource Group Agency, LLC, an Ohio-based benefits consulting firm and Presidio Benefits Group, Inc., a California-based employee benefits consulting firm.

• December – Marsh acquired AD Corretora, a multi-line broker located in Brazil, and Bluefin Insurance Group, Ltd, a U.K.-based insurance brokerage.

The Consulting segment completed six acquisitions during 2016.

• January – Mercer acquired The Positive Ageing Company Limited, a U.K.-based firm providing advice on issues surrounding the aging workforce.

• April – Mercer acquired the Extratextual software system and related client contracts. Extratextual is a web based compliance system that assists clients to manage and meet their compliance and risk management obligations.

• December – Oliver Wyman acquired LShift Limited, a software development company, and Mercer acquired Sirota Consulting LLC, a global provider of employee benefit solutions; Pillar Administration, a superannuation provider located in Australia; and Thomsons Online Benefits, a U.K.-based global benefits software business.

Total purchase consideration for acquisitions made during the first nine months of 2016 was $119 million, which consisted of cash paid of $90 million and deferred purchase and estimated contingent consideration of $29 million. Contingent consideration arrangements are primarily based on EBITDA or revenue targets over a period of two to four years. The fair value of the contingent consideration was based on projected revenue or earnings of the acquired entities. Estimated fair values of assets acquired and liabilities assumed are subject to adjustment when purchase accounting is finalized. In the first nine months of 2016, the Company also paid $53 million of deferred purchase consideration and $85 million of contingent consideration related to acquisitions made in prior years.

Pro-Forma Information

The following unaudited pro-forma financial data gives effect to the acquisitions made by the Company during 2017 and 2016. In accordance with accounting guidance related to pro-forma disclosures, the information presented for current year acquisitions is as if they occurred on January 1, 2016 and reflects acquisitions made in 2016 as if they occurred on January 1, 2015. The unaudited pro-forma information adjusts for the effects of amortization of acquired intangibles. The unaudited pro-forma financial data is presented for illustrative purposes only and is not necessarily indicative of the operating results that would have been achieved if such acquisitions had occurred on the dates indicated, nor is it necessarily indicative of future consolidated results.

	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share figures)	2017		2016		2017		2016
Revenue	$	3,349	$	3,256	$	10,416	$	10,232
Net income attributable to the Company	$	392	$	372	$	1,466	$	1,320
Basic net income per share attributable to the Company	$	0.77	$	0.72	$	2.85	$	2.54
Diluted net income per share attributable to the Company	$	0.76	$	0.71	$	2.82	$	2.52

The consolidated statements of income include the results of operations of acquired companies since their respective acquisition dates. The consolidated statements of income for the three and nine-month periods ended

16

September 30, 2017 include approximately $40 million and$103 million of revenue, respectively, and an operating loss of $1 million and operating income of $16 million, respectively, related to acquisitions made in 2017.

8.    Goodwill and Other Intangibles

The Company is required to assess goodwill and any indefinite-lived intangible assets for impairment annually, or more frequently if circumstances indicate impairment may have occurred. The Company performs the annual impairment assessment for each of its reporting units during the third quarter of each year. In accordance with applicable accounting guidance, the Company assesses qualitative factors to determine whether it is necessary to perform the two-step goodwill impairment test. The Company considers numerous factors, which include whether the fair value of each reporting unit exceeded its carrying value by a substantial margin in its most recent estimate of reporting unit fair values, whether significant acquisitions or dispositions occurred which might alter the fair value of its reporting units, macroeconomic conditions and their potential impact on reporting unit fair values, actual performance compared with budget and prior projections used in its estimation of reporting unit fair values, industry and market conditions, and the year-over-year change in the Company’s share price. The Company completed its qualitative assessment in the third quarter of 2017 and concluded that a two-step goodwill impairment test was not required in 2017 and that goodwill was not impaired.

Changes in the carrying amount of goodwill are as follows:

September 30,
(In millions)	2017		2016
Balance as of January 1, as reported	$	8,369	$	7,889
Goodwill acquired	533		74
Other adjustments(a)	198		12
Balance at September 30,	$	9,100	$	7,975

^(a)  The increase in 2017 primarily reflects the impact of foreign exchange.

Goodwill allocable to the Company’s reportable segments at September 30, 2017 is as follows: Risk and Insurance Services, $6.5 billion and Consulting, $2.6 billion.

Other intangible assets that are not deemed to have an indefinite life are amortized over their estimated lives and reviewed for impairment upon the occurrence of certain triggering events in accordance with applicable accounting literature.

The gross cost and accumulated amortization at September 30, 2017 and December 31, 2016 are as follows:

	September 30, 2017						December 31, 2016
(In millions)	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Client Relationships	$	1,679	$	487	$	1,192	$	1,390	$	392	$	998
Other (a)	231		103		128		204		76		128
Amortized intangibles	$	1,910	$	590	$	1,320	$	1,594	$	468	$	1,126

^(a) Primarily non-compete agreements, trade names and developed technology.

Aggregate amortization expense for the nine months ended September 30, 2017 and2016 was $122 million and $99 million, respectively. The estimated future aggregate amortization expense is as follows:

For the Years Ending December 31,
(In millions)	Estimated Expense
2017 (excludes amortization through September 30, 2017)	$	50
2018	176
2019	166
2020	145
2021	135
Subsequent years	648
	$	1,320

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9.     Fair Value Measurements

Fair Value Hierarchy

The Company has categorized its assets and liabilities that are valued at fair value on a recurring basis into a three-level fair value hierarchy as defined by the Financial Accounting Standards Board ("FASB"). The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets and liabilities (Level 1) and lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy, for disclosure purposes, is determined based on the lowest level input that is significant to the fair value measurement. Assets and liabilities recorded in the consolidated balance sheets at fair value are categorized based on the inputs in the valuation techniques as follows:

Level 1. Assets and liabilities whose values are based on unadjusted quoted prices for identical assets or liabilities in an active market (examples include active exchange-traded equity securities and exchange-traded money market mutual funds).

Assets and liabilities measured using Level 1 inputs include exchange-traded equity securities, exchange-traded mutual funds and money market funds.

Level 2. Assets and liabilities whose values are based on the following:

a) Quoted prices for similar assets or liabilities in active markets;

b) Quoted prices for identical or similar assets or liabilities in non-active markets (examples include corporate and municipal bonds, which trade infrequently);

c) Pricing models whose inputs are observable for substantially the full term of the asset or liability (examples include most over-the-counter derivatives, including interest rate and currency swaps); and

d) Pricing models whose inputs are derived principally from or corroborated by observable market data through correlation or other means for substantially the full asset or liability (for example, certain mortgage loans).

The Company does not have any assets or liabilities that are measured using Level 2 inputs.

Level 3. Assets and liabilities whose values are based on prices, or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs reflect management’s own assumptions about the assumptions a market participant would use in pricing the asset or liability.

Liabilities measured using Level 3 inputs include liabilities for contingent purchase consideration.

Valuation Techniques

Equity Securities, Money Market Funds and Mutual Funds – Level 1

Investments for which market quotations are readily available are valued at the sale price on their principal exchange or, for certain markets, official closing bid price. Money market funds are valued using a valuation technique that results in price per share at $1.00.

Contingent Purchase Consideration Liability – Level 3

Purchase consideration for some acquisitions made by the Company includes contingent consideration arrangements. These arrangements typically provide for the payment of additional consideration if earnings or revenue targets are met over periods from two to four years. The fair value of the contingent purchase consideration liability is estimated as the present value of future cash flows to be paid, based on projections of revenue and earnings and related targets of the acquired entities.

18

The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016.

	Identical Assets (Level 1)				Observable Inputs (Level 2)				Unobservable Inputs (Level 3)				Total
(In millions)	09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16
Assets:
Financial instruments owned:
Exchange traded equity securities(a)	$	99	$	89	$	—	$	—	$	—	$	—	$	99	$	89
Mutual funds(a)	143		141		—		—		—		—		143		141
Money market funds(b)	54		22		—		—		—		—		54		22
Total assets measured at fair value	$	296	$	252	$	—	$	—	$	—	$	—	$	296	$	252
Fiduciary Assets:
Money market funds	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Total fiduciary assets measured at fair value	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Liabilities:
Contingent purchase consideration liability(c)	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241
Total liabilities measured at fair value	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241

^(a)  Included in other assets in the consolidated balance sheets.

^(b)  Included in cash and cash equivalents in the consolidated balance sheets.

^(c)  Included in accounts payable and accrued liabilities and other liabilities in the consolidated balance sheets.

During the nine-month period ended September 30, 2017, there were no assets or liabilities that were transferred between any of the levels.

The table below sets forth a summary of the changes in fair value of the Company’s Level 3 liabilities as of September 30, 2017 and 2016 that represent contingent consideration related to acquisitions:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Balance at beginning of period,	$	203		$	279		$	241		$	309
Additions	2			1			36			9
Payments	(42		)	(35		)	(107		)	(85		)
Revaluation Impact	5			(13		)	(3		)	5
Other (a)	2			—			3			(6		)
Balance at September 30,	$	170		$	232		$	170		$	232

^(a) Primarily reflects the impact of foreign exchange.

The fair value of the contingent purchase consideration liability is based on projections of revenue and EBITDA for the acquired entities in relation to the established targets and is reassessed on a quarterly basis. As set forth in the table above, based on the Company's ongoing assessment of the fair value of contingent consideration, the Company recorded a net decrease in the estimated fair value of such liabilities for prior-period acquisitions of $3 million in the nine-month period ended September 30, 2017. A 5% increase in the above mentioned projections would increase the liability by approximately $18 million. A 5% decrease in the above mentioned projections would decrease the liability by approximately $19 million.

Long-Term Investments

The Company holds investments in certain private equity investments, public companies and private companies that are accounted for using the equity method of accounting. The carrying value of these investments was $405 million and $389 million at September 30, 2017 and December 31, 2016, respectively.

19

Private Equity Investments

The Company's investments in private equity funds were $72 million and $79 million at September 30, 2017 and December 31, 2016, respectively. The carrying values of these private equity investments approximate fair value. The underlying private equity funds follow investment company accounting, where investments within the fund are carried at fair value. The Company records in earnings, investment gains/losses for its proportionate share of the change in fair value of the funds. These investments are included in other assets in the consolidated balance sheets.

Investments in Public and Private Companies

Alexander Forbes: The Company owns approximately 33% of the common stock of Alexander Forbes, a South African company listed on the Johannesburg Stock Exchange, which it purchased in 2014 for 7.50 South African Rand per share. As of September 30, 2017, the carrying value of the Company’s investment in Alexander Forbes was approximately $268 million. As of September 30, 2017, the market value of the approximately 443 million shares of Alexander Forbes owned by the Company, based on the September 30, 2017 closing share price of 6.75 South African Rand per share, was approximately $225 million. The Company considered several factors in assessing its investment in Alexander Forbes, including its financial position, the near- and long-term prospects of Alexander Forbes and the broader South African economy and capital markets, the length of time and extent to which the market value was below cost and the Company’s intent and ability to retain the investment for a sufficient period of time to allow for anticipated recovery in market value. During the first nine months of 2017, the daily closing share price ranged from a high of 7.89 Rand (in early January) to a low of 5.99 Rand (in late April). During the third quarter of 2017, the Alexander Forbes average opening and closing stock price was approximately 6.75 Rand (approximately 90% of the original purchase price) and ranged from 6.40 Rand to 7.28 Rand (approximately 85% to 97% of the purchase price). Based on its assessment of the factors discussed above, the Company determined the investment was not impaired.

The Company’s investment in Alexander Forbes and its other equity investments in private insurance and consulting companies are accounted for using the equity method of accounting, the results of which are included in revenue in the consolidated statements of income and the carrying value of which is included in other assets in the consolidated balance sheets. The Company records its share of income or loss on its equity method investments on a one quarter lag basis.

Benefitfocus: On February 24, 2015, the Company purchased shares of common stock of Benefitfocus (NASDAQ:BNFT) constituting 9.9% of BNFT's outstanding capital stock as of the acquisition date. The purchase price for the BNFT shares and certain other rights and other consideration was approximately $75 million. Until December 31, 2016, the Company accounted for this investment under the cost method of accounting as the shares purchased were categorized as restricted. Effective December 31, 2016, these shares were no longer considered restricted for the purpose of determining if they are marketable securities under applicable accounting guidance, and are now accounted for as available for sale securities and included in other assets in the consolidated balance sheets. The value of the BNFT shares based on the closing price on the NASDAQ as of September 30, 2017 was approximately $95 million. During the first nine months of 2017 an unrealized gain related to these shares of approximately $11 million was recorded in other comprehensive income.

10.    Retirement Benefits

The Company maintains qualified and non-qualified defined benefit pension plans for some of its U.S. and non-U.S. eligible employees. The Company’s policy for funding its tax-qualified defined benefit pension plans is to contribute amounts at least sufficient to meet the funding requirements set forth by U.S. law and the laws of the non-U.S. jurisdictions in which the Company offers such plans.

The target asset allocation for the Company's U.S. Plan was 64% equities and equity alternatives and 36% fixed income and at September 30, 2017, the actual allocation for the Company's U.S. Plan was 65% equities and equity alternatives and 35% fixed income. The target allocation for the U.K. plans at September 30, 2017 was46% equities and equity alternatives and 54% fixed income. At September 30, 2017, the actual allocation for the U.K. Plans was 47% equities and equity alternatives and 53% fixed income. The Company's U.K. Plans comprised approximately 81% of non-U.S. plan assets at December 31, 2016. The assets of the Company's defined benefit plans are diversified and are managed in accordance with applicable laws and with the goal of maximizing the plans' real return within acceptable risk parameters. The Company generally uses threshold-based portfolio re-balancing to ensure the actual portfolio remains consistent with target asset allocation ranges.

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The components of the net periodic benefit cost for defined benefit and other post-retirement plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	43		$	—	$	1
Interest cost	125			132			1		—
Expected return on plan assets	(232		)	(232		)	—		—
Amortization of prior service cost	—			1			1		1
Recognized actuarial loss	42			43			—		—
Net periodic benefit (credit) cost	$	(46	)	$	(13	)	$	2	$	2
Settlement loss	1			—			—		—
Total (credit) cost	$	(45	)	$	(13	)	$	2	$	2
Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	56		$	133		$	—	$	1
Interest cost	371			407			3		3
Expected return on plan assets	(686		)	(715		)	—		—
Amortization of prior service (credit) cost	(1		)	—			2		3
Recognized actuarial loss (gain)	125			127			—		(1		)
Net periodic benefit (credit) cost	$	(135	)	$	(48	)	$	5	$	6
Curtailment gain	(1		)	(5		)	—		—
Settlement loss	2			1			—		—
Total (credit) cost	$	(134	)	$	(52	)	$	5	$	6
U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	—		$	26		$	—	$	—
Interest cost	66			66			—		—
Expected return on plan assets	(89		)	(95		)	—		—
Amortization of prior service cost	—			—			1		1
Recognized actuarial loss	9			19			—		—
Net periodic benefit (credit) cost	$	(14	)	$	16		$	1	$	1

U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	—		$	79		$	—		$	—
Interest cost	198			198			1			1
Expected return on plan assets	(268		)	(285		)	—			—
Amortization of prior service cost	—			—			3			3
Recognized actuarial loss (gain)	28			55			(1		)	(1		)
Net periodic benefit (credit) cost	$	(42	)	$	47		$	3		$	3

21

In October 2016, the Company modified its U.S. defined benefit pension plans to discontinue further benefit accruals for participants after December 31, 2016. At the same time, the Company amended its U.S. defined contribution retirement plans for most of its U.S. employees to add an automatic Company contribution equal to 4% of eligible base pay beginning on January 1, 2017. This new Company contribution, together with the Company’s current matching contribution, provides eligible U.S. employees with the opportunity to receive a total contribution of up to 7% of eligible base pay. In addition, the U.S. qualified defined benefit plans were merged effective December 30, 2016.

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	17		$	—	$	1
Interest cost	59			66			1		—
Expected return on plan assets	(143		)	(137		)	—		—
Amortization of prior service cost	—			1			—		—
Recognized actuarial loss	33			24			—		—
Net periodic benefit (credit) cost	$	(32	)	$	(29	)	$	1	$	1
Settlement loss	1			—			—		—
Total (credit) cost	$	(31	)	$	(29	)	$	1	$	1

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	56		$	54		$	—		$	1
Interest cost	173			209			2			2
Expected return on plan assets	(418		)	(430		)	—			—
Amortization of prior service credit	(1		)	—			(1		)	—
Recognized actuarial loss	97			72			1			—
Net periodic benefit (credit) cost	$	(93	)	$	(95	)	$	2		$	3
Curtailment gain	(1		)	(5		)	—			—
Settlement loss	2			1			—			—
Total (credit) cost	$	(92	)	$	(99	)	$	2		$	3

In March 2017, the Company modified its defined benefit pension plans in Canada to discontinue further benefit accruals for participants after December 31, 2017 and replaced them with a defined contribution arrangement. The Company also amended its post-retirement benefits plan in Canada so that individuals who retire after April 1, 2019 will not be eligible to participate, except in certain situations. The Company re-measured the assets and liabilities of the plans, based on assumptions and market conditions on the amendment date.

The weighted average actuarial assumptions utilized to calculate the net periodic benefit costs for the U.S. and significant non-U.S. defined benefit plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits				Post-retirement Benefits
September 30,	2017		2016		2017		2016
Weighted average assumptions:
Expected return on plan assets	6.64	%	7.07	%	—		—
Discount rate	3.40	%	4.11	%	3.64	%	4.12	%
Rate of compensation increase*	1.77	%	2.44	%	—		—

*The 2017 assumption does not include a rate of compensation increase for the U.S. defined benefit plans since future benefit accruals were discontinued for those plans after December 31, 2016.

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The Company made approximately $193 million of contributions to its U.S. and non-U.S. defined benefit plans in the first nine months of 2017. The Company expects to contribute approximately $63 million to its U.S. pension and non-U.S. pension plans during the remainder of 2017.

Defined Contribution Plans

The Company maintains certain defined contribution plans for its employees, the most significant being in the U.S. and the U.K. The cost of these U.S. and U.K. defined contribution plans was $99 million and $56 million, respectively, for the nine months ended September 30,2017.

11.    Debt

The Company’s outstanding debt is as follows:

(In millions)	September 30, 2017		December 31, 2016
Short-term:
Commercial paper	$	—	$	50
Current portion of long-term debt	13		262
	13		312
Long-term:
Senior notes – 2.30% due 2017	—		250
Senior notes – 2.55% due 2018	250		249
Senior notes – 2.35% due 2019	299		299
Senior notes – 2.35% due 2020	498		497
Senior notes – 4.80% due 2021	498		498
Senior notes – 2.75% due 2022	496		—
Senior notes – 3.30% due 2023	347		347
Senior notes – 4.05% due 2023	248		248
Senior notes – 3.50% due 2024	596		596
Senior notes – 3.50% due 2025	496		495
Senior notes – 3.75% due 2026	596		596
Senior notes – 5.875% due 2033	297		297
Senior notes – 4.35% due 2047	492		—
Mortgage – 5.70% due 2035	373		382
Other	2		3
	5,488		4,757
Less current portion	13		262
	$	5,475	$	4,495

The senior notes in the table above are registered by the Company with the Securities and Exchange Commission and are not guaranteed.

The Company has established a short-term debt financing program of up to $1.5 billion through the issuance of commercial paper. The proceeds from the issuance of commercial paper are used for general corporate purposes. The Company had no commercial paper outstanding at September 30, 2017.

In January 2017, the Company issued $500 million of 2.75% senior notes due 2022 and $500 million of 4.35% senior notes due 2047. The Company used the net proceeds for general corporate purposes, including the repayment of a $250 million debt maturity in April 2017.

In March 2016, the Company issued $350 million of 3.30%seven-year senior notes. The Company used the net proceeds for general corporate purposes.

The Company and certain of its foreign subsidiaries maintain a $1.5 billion multi-currency five-year unsecured revolving credit facility. The interest rate on this facility is based on LIBOR plus a fixed margin which varies with the Company's credit ratings. This facility expires in November 2020 and requires the Company to maintain certain coverage and leverage ratios which are tested quarterly. There were no borrowings outstanding under this facility at September 30, 2017.

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Fair Value of Short-term and Long-term Debt

The estimated fair value of the Company’s short-term and long-term debt is provided below. Certain estimates and judgments were required to develop the fair value amounts. The fair value amounts shown below are not necessarily indicative of the amounts that the Company would realize upon disposition, nor do they indicate the Company’s intent or need to dispose of the financial instrument.

	September 30, 2017				December 31, 2016
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Short-term debt	$	13	$	13	$	312	$	313
Long-term debt	$	5,475	$	5,720	$	4,495	$	4,625

The fair value of the Company’s short-term debt consists primarily of term debt maturing within the next year and its fair value approximates its carrying value. The estimated fair value of a primary portion of the Company's long-term debt is based on discounted future cash flows using current interest rates available for debt with similar terms and remaining maturities. Short- and long-term debt would be classified as Level 2 in the fair value hierarchy.

12.    Restructuring Costs

The Company recorded total restructuring costs of $32 million in the first nine months of 2017, primarily for severance at Mercer, Marsh and Corporate, as well as future rent under non-cancelable leases at Corporate. These costs were incurred in Risk and Insurance Services ($7 million), Consulting ($18 million) and Corporate ($7 million).

Details of the restructuring activity from January 1, 2016 through September 30, 2017, which includes liabilities from actions prior to 2017, are as follows:

(In millions)	Liability at 1/1/16		Amounts Accrued		Cash Paid			Other			Liability at 12/31/16		Amounts Accrued		Cash Paid			Other		Liability at 9/30/17
Severance	$	15	$	40	$	(22	)	$	(1	)	$	32	$	24	$	(42	)	$	—	$	14
Future rent under non-cancelable leases and other costs	78		4		(17		)	(4		)	61		8		(15		)	1		55
Total	$	93	$	44	$	(39	)	$	(5	)	$	93	$	32	$	(57	)	$	1	$	69

The expenses associated with the above initiatives are included in compensation and benefits and other operating expenses in the consolidated statements of income. The liabilities associated with these initiatives are classified on the consolidated balance sheets as accounts payable and accrued liabilities, other liabilities or accrued compensation and employee benefits, depending on the nature of the items.

13.    Common Stock

During the first nine months of 2017, the Company repurchased approximately 8.0 million shares of its common stock for consideration of $600 million. During the first nine months of 2016, the Company repurchased approximately 10.0 million shares of its common stock for consideration of $625 million. In November 2016, the Board of Directors of the Company authorized the Company to repurchase up to $2.5 billion in shares of the Company's common stock, which superseded any prior authorizations. As of September 30, 2017, the Company remained authorized to repurchase up to approximately $1.8 billion in shares of its common stock. There is no time limit on the authorization.

The Company issued approximately 4.6 million and 4.5 million shares related to stock compensation and employee stock purchase plans during the first nine months of 2017 and 2016, respectively.

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14.    Claims, Lawsuits and Other Contingencies

Litigation Matters

The Company and its subsidiaries are subject to a significant number of claims, lawsuits and proceedings in the ordinary course of business. Such claims and lawsuits consist principally of alleged errors and omissions in connection with the performance of professional services, including the placement of insurance, the provision of actuarial services for corporate and public sector clients, the provision of investment advice and investment management services to pension plans, the provision of advice relating to pension buy-out transactions and the provision of consulting services relating to the drafting and interpretation of trust deeds and other documentation governing pension plans. These claims may seek damages, including punitive and treble damages, in amounts that could be significant. In establishing liabilities for errors and omissions claims in accordance with FASB guidance on Contingencies - Loss Contingencies, the Company uses case level reviews by inside and outside counsel, and internal actuarial analysis by Oliver Wyman Group, a subsidiary of the Company, and other methods to estimate potential losses. A liability is established when a loss is both probable and reasonably estimable. The liability is reviewed quarterly and adjusted as developments warrant. In many cases, the Company has not recorded a liability, other than for legal fees to defend the claim, because we are unable, at the present time, to make a determination that a loss is both probable and reasonably estimable.

To the extent that expected losses exceed our deductible in any policy year, the Company also records an asset for the amount that we expect to recover under any available third-party insurance programs. The Company has varying levels of third-party insurance coverage, with policy limits and coverage terms varying significantly by policy year.

Governmental Inquiries and Enforcement Matters

Our activities are regulated under the laws of the United States and its various states, the European Union and its member states, and the other jurisdictions in which the Company operates.

Risk and Insurance Services Segment

In April 2017, the Financial Conduct Authority in the United Kingdom (the "FCA") commenced a civil competition investigation into the aviation insurance and reinsurance sector. In connection with that investigation, the FCA carried out an on-site inspection at the London office of Marsh Limited, our Marsh and Guy Carpenter operating subsidiary in the United Kingdom. The FCA indicated that it had reasonable grounds for suspecting that Marsh Limited and other participants in the market have been sharing competitively sensitive information within the aviation insurance and reinsurance broking sector.

In October 2017, the Company received a notice that the Directorate-General for Competition of the European Commission had commenced a civil investigation of a number of insurance brokers, including Marsh, regarding "the exchange of commercially sensitive information between competitors in relation to aviation and aerospace insurance and reinsurance broking products and services in the European Economic Area ("EEA"), as well as possible coordination between competitors." In light of the action taken by the European Commission, the FCA informed Marsh Limited at the same time that it has discontinued its investigation under U.K. competition law into the aviation insurance and reinsurance sector.

In July 2017, the Directorate-General for Competition of the European Commission together with the Irish Competition and Consumer Protection Commission conducted on-site inspections at the offices of Marsh and other industry participants in Dublin in connection with an investigation regarding the "possible participation in anticompetitive agreements and/or concerted practices contrary to [E.U. competition law] in the market for commercial motor insurance in the Republic of Ireland."

We are cooperating with these investigations and are conducting our own reviews. As these investigations are at early stages, we are unable to predict their likely timing, outcome or ultimate impact. There can be no assurance that the ultimate resolution of these or any related matters will not have a material adverse effect on our consolidated results of operations, financial condition or cash flows.

Consulting Segment

In June 2017, the FCA issued a final report in connection with a market study of the U.K. asset management industry, which includes asset managers and investment consultants, including Mercer. Following the report, in September 2017, the FCA announced its decision to refer the investment consulting and fiduciary management markets to the U.K. Competition & Markets Authority (the "CMA") for a market investigation. The CMA expects to conclude its investigation of the investment consulting and fiduciary management markets by March 2019.

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In the ordinary course of business, the Company is also subject to other investigations, subpoenas, lawsuits and other regulatory actions undertaken by governmental authorities.

Other Contingencies-Guarantees

In connection with its acquisition of U.K.-based Sedgwick Group in 1998, the Company acquired several insurance underwriting businesses that were already in run-off, including River Thames Insurance Company Limited ("River Thames"), which the Company sold in 2001. Sedgwick guaranteed payment of claims on certain policies underwritten through the Institute of London Underwriters (the "ILU") by River Thames. The policies covered by this guarantee were reinsured up to £40 million by a related party of River Thames. Payment of claims under the reinsurance agreement is collateralized by segregated assets held in a trust. As of September 30, 2017, the reinsurance coverage exceeded the best estimate of the projected liability of the policies covered by the guarantee. To the extent River Thames or the reinsurer is unable to meet its obligations under those policies, a claimant may seek to recover from the Company under the guarantee.

From 1980 to 1983, the Company owned indirectly the English & American Insurance Company ("E&A"), which was a member of the ILU. The ILU required the Company to guarantee a portion of E&A's obligations. After E&A became insolvent in 1993, the ILU agreed to discharge the guarantee in exchange for the Company's agreement to post an evergreen letter of credit that is available to pay claims by policyholders on certain E&A policies issued through the ILU and incepting between July 3, 1980 and October 6, 1983. Certain claims have been paid under the letter of credit and the Company anticipates that additional claimants may seek to recover against the letter of credit.

* * * *

The pending proceedings described above and other matters not explicitly described in this Note 14 on Claims, Lawsuits and Other Contingencies may expose the Company or its subsidiaries to liability for significant monetary damages, fines, penalties or other forms of relief. Where a loss is both probable and reasonably estimable, the Company establishes liabilities in accordance with FASB guidance on Contingencies - Loss Contingencies. Except as described above, the Company is not able at this time to provide a reasonable estimate of the range of possible loss attributable to these matters or the impact they may have on the Company's consolidated results of operations, financial position or cash flows. This is primarily because these matters are still developing and involve complex issues subject to inherent uncertainty. Adverse determinations in one or more of these matters could have a material impact on the Company's consolidated results of operations, financial condition or cash flows in a future period.

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15.    Segment Information

The Company is organized based on the types of services provided. Under this structure, the Company’s segments are:

▪ Risk and Insurance Services, comprising insurance services (Marsh) and reinsurance services (Guy Carpenter); and

▪ Consulting, comprising Mercer and Oliver Wyman Group.

The accounting policies of the segments are the same as those used for the consolidated financial statements described in Note 1 to the Company’s 2016 Form 10-K. Segment performance is evaluated based on segment operating income, which includes directly related expenses, and charges or credits related to integration and restructuring but not the Company’s corporate-level expenses. Revenues are attributed to geographic areas on the basis of where the services are performed.

Selected information about the Company’s operating segments for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,							Nine Months Ended September 30,
(In millions)	Revenue				Operating Income (Loss)			Revenue				Operating Income (Loss)
2017–
Risk and Insurance Services	$	1,763		(a)	$	314		$	5,668		(c)	$	1,455
Consulting	1,587			(b)	329			4,705			(d)	853
Total Operating Segments	3,350				643			10,373				2,308
Corporate / Eliminations	(9		)		(46		)	(34		)		(138		)
Total Consolidated	$	3,341			$	597		$	10,339			$	2,170
2016–
Risk and Insurance Services	$	1,632		(a)	$	315		$	5,350		(c)	$	1,340
Consulting	1,513			(b)	308			4,530			(d)	838
Total Operating Segments	3,145				623			9,880				2,178
Corporate / Eliminations	(10		)		(51		)	(33		)		(147		)
Total Consolidated	$	3,135			$	572		$	9,847			$	2,031

^(a)  Includes inter-segment revenue of $1 million in both 2017and2016, interest income on fiduciary funds of $11 million and $8 million in 2017 and 2016, respectively, and equity method income of $2 million and $4 million in 2017 and 2016, respectively.

^(b)  Includes inter-segment revenue of $8 million and $9 million in 2017 and 2016, respectively, interest income on fiduciary funds of $2 million in 2017 and $1 million in 2016, respectively, and equity method income of $3 million in 2017 and $5 million in 2016, respectively.

^(c)  Includes inter-segment revenue of $5 million in both 2017 and2016, interest income on fiduciary funds of $28 million and $20 million in 2017 and 2016, respectively, and equity method income of $11 million in both 2017 and 2016.

^(d)  Includes inter-segment revenue of $29 million and $28 million in 2017 and 2016, respectively, interest income on fiduciary funds of $3 million in 2017 and $2 million in 2016, respectively, and equity method income of $12 million in 2017 and $14 million in 2016, respectively.

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Details of operating segment revenue for the three and nine-month period ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Risk and Insurance Services
Marsh	$	1,490		$	1,370		$	4,713		$	4,427
Guy Carpenter	273			262			955			923
Total Risk and Insurance Services	1,763			1,632			5,668			5,350
Consulting
Mercer	1,149			1,109			3,335			3,227
Oliver Wyman Group	438			404			1,370			1,303
Total Consulting	1,587			1,513			4,705			4,530
Total Operating Segments	3,350			3,145			10,373			9,880
Corporate / Eliminations	(9		)	(10		)	(34		)	(33		)
Total	$	3,341		$	3,135		$	10,339		$	9,847

16.    New Accounting Guidance

In March 2017, the FASB issued new guidance that changes the presentation of net periodic pension cost and net periodic postretirement cost (''net periodic benefit costs"). The new guidance requires employers to report the service cost component of net periodic benefit costs in the same line item as other compensation costs in the income statement. The other components of net periodic benefit costs are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. In addition, only the service cost component is eligible for capitalization, when applicable. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted as of the beginning of an annual period for which financial statements (interim or annual) have not been issued or made available for issuance. The new guidance requires retrospective application for the presentation of the service cost component and the other components of net periodic benefit costs, and prospective application for the capitalization of the service cost component. The adoption of this guidance will impact the presentation of the Company's results of operations, in particular, reducing net operating income, but will have no impact on the Company's net income.

In January 2017, the FASB issued new guidance to simplify the test for goodwill impairment. The new guidance eliminates the second step in the current two-step goodwill impairment process, under which a goodwill impairment loss is measured by comparing the implied fair value of a reporting unit's goodwill with the carrying amount of that goodwill for that reporting unit. The new guidance requires a one-step impairment test, in which the goodwill impairment charge is based on 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. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The guidance should be applied on a prospective basis with the nature of and reason for the change in accounting principle disclosed upon transition. The guidance is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In January 2017, the FASB issued guidance which clarifies the definition of a business in order to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted under certain circumstances and the guidance must be applied prospectively as of the beginning of the period of adoption. The Company is currently evaluating the impact, if any, the adoption of this standard will have on its financial position or results of operations.

In November 2016, the FASB issued new guidance which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. As a result, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-

28

of-period total amounts shown on the statement of cash flows. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented. Early adoption is permitted. The adoption of this guidance is not expected to have an impact on the Company's consolidated balance sheets or consolidated statements of cash flows.

In October 2016, the FASB also issued new guidance which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance eliminates the exception for an intra-entity transfer of an asset other than inventory. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The new guidance must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In August 2016, the FASB issued new guidance which adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows, including cash payments for debt prepayments or debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investees. The guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented unless retrospective application is impracticable. Early adoption is permitted. The Company does not expect the adoption of this standard to have a significant impact on its statement of cash flows.

In February 2016, the FASB issued new guidance intended to improve financial reporting for leases. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a financing or operating lease. However, unlike current GAAP, which requires that only capital leases be recognized on the balance sheet, the new guidance requires that both types of leases be recognized on the balance sheet. The new guidance will require additional disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, and additional information about the amounts recorded in the financial statements. The accounting by organizations that own the assets ("lessor") leased by the lessee will remain largely unchanged from current GAAP. However, the guidance contains some targeted improvements that are intended to align, where necessary, lessor accounting with the lessee accounting model and with the updated revenue recognition guidance issued in 2014. The new guidance on leases will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early application will be permitted. The Company is currently evaluating the impact the adoption of the guidance will have on its financial position and results of operations, but expects material "right to use" assets and lease liabilities to be recorded on its consolidated balance sheets.

In January 2016, the FASB issued new guidance intended to improve the recognition and measurement of financial instruments. The new guidance requires equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requires a reporting organization to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (also referred to as "own credit") when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company holds certain equity investments that are currently treated as available for sale securities, whereby the mark to market change is recorded to other comprehensive income in its consolidated balance sheet. The adoption of this new standard will impact the Company's results of operations, since the mark to market change to certain of its equity investments will be recorded in the consolidated income statement (See Note 9).

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New Revenue Recognition Pronouncement

In May 2014, the FASB issued new accounting guidance to clarify the principles for revenue recognition. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised 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. To achieve that principle, the entity should apply the following steps: identify the contract(s) with the customer, identify the performance obligations in the contract(s), determine the transaction price, allocate the transaction price to the performance obligations in the contract and recognize revenue when (or as) the entity satisfies a performance obligation. The guidance includes requirements to estimate variable or contingent consideration, which will result in revenue being recognized earlier than legacy GAAP. In addition, the guidance requires the capitalization and amortization of certain expenses which were expensed as incurred under legacy GAAP. As discussed in more detail below, the Company expects that once the standard is adopted as of January 1, 2018 revenue will shift among quarters, but does not expect a significant year-over-year impact on annual revenue.

The Company expects there will be significant movement in the quarterly timing of revenue recognition in the Risk and Insurance Services segment. In particular, under the new standard the recognition of revenue in the Company’s reinsurance broking operations will be accelerated from historical patterns. Currently, revenue related to most reinsurance placements is recognized on the later of billing or effective date as premiums are written and attached to the reinsurance treaties. This typically results in revenue being recognized over a 12 to 24 month period. Under the new guidance, revenue will be recognized largely at the policy effective date. In the insurance brokerage operations, revenue from commission based arrangements will continue to be recorded at the policy effective date, while the timing of revenue recognition for certain fee based arrangements will shift among quarters. However since the vast majority of our fee arrangements involve contracts that cover a single year of services, the Company does not believe there will be a significant change to the amount of revenue recognized in an annual period once the standard is adopted.

The Company believes application of the new standard in the Consulting segment will not materially change the existing timing of revenue recognition in quarterly or annual periods. The conclusions will be completed following a final review of customer arrangement legal terms and conditions in certain non-U.S. locations.

The Company expects that certain costs that are currently expensed will be capitalized as costs to obtain or costs to fulfill customer contracts under the new standard. Incremental costs to obtain a contract would generally be amortized over the expected life of the underlying customer relationship under the new guidance. The Company currently expenses those costs as incurred.

In Risk and Insurance Services, certain pre-placement costs will be deferred and "amortized" when the related services are transferred, generally over a period of one year or less. As such, the Company expects the recognition of costs to shift among quarters, but similar to the revenue impact discussed above, does not expect a significant impact on year over year expenses once the standard is adopted.

In several of its businesses, the Company incurs implementation costs necessary to facilitate the delivery of the contracted services. Although certain implementation costs are deferred under current GAAP, the Company has concluded that some additional implementation costs currently expensed under GAAP will be deferred. In addition, the amortization period for these costs will have a longer amortization period which includes the initial contract plus expected renewals. Currently, these deferred implementation costs are amortized over the initial contract term. The Company has not yet fully quantified the impact of the changes discussed above. However, the Company expects that it will recognize a significant amount of contract assets and/or receivables upon implementation of the standard, related to both capitalized costs to obtain and fulfill contracts, as well as commissions related to reinsurance brokerage activity.

The Company is currently designing and implementing changes in processes, controls and systems necessary to support the new revenue recognition requirements.

Entities are permitted to adopt the guidance under one of the following methods: the "full retrospective" method, which applies the guidance to each period presented (prior years restated) or the "modified retrospective" method in which the guidance is only applied to the year of adoption, with the cumulative effect of initially applying the guidance recognized as an adjustment to retained earnings. The Company will adopt the new guidance effective January 1, 2018 and expects to use the modified retrospective method.

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New Accounting Pronouncements Recently Adopted

In October 2016, the FASB issued new guidance which changes the evaluation of whether a reporting entity is the primary beneficiary of a variable interest entity by changing how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. If a reporting entity satisfies the first characteristic of a primary beneficiary (such that it is the single decision maker of a variable interest entity), the new guidance requires that reporting entity, in determining whether it satisfies the second characteristic of a primary beneficiary, to include all of its direct variable interest in a variable interest entity and, on a proportionate basis, its indirect variable interests in a variable interest entity held through related parties, including related parties that are under common control with the reporting entity. The adoption of this guidance did not have a significant impact on its financial position, results of operations and statement of cash flows.

In April 2016, the FASB issued new guidance which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. The new guidance requires that companies record all excess tax benefits and tax deficiencies as an income tax benefit or expense in the income statement and classify excess tax benefits as an operating activity in the statement of cash flows. The Company adopted this new guidance prospectively, effective January 1, 2017 and prior periods have not been adjusted. For the nine months ended September 30, 2017, the adoption of this new standard reduced income tax expense in the consolidated statement of income by approximately $58 million. For the nine months ended September 30, 2016, the Company recorded an excess tax benefit of $30 million as an increase to equity in its consolidated balance sheet, which was reflected as cash provided by financing activities in the consolidated statement of cash flows.

In March 2016, the FASB issued new guidance which eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The new guidance is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. The guidance was adopted on January 1, 2017 and did not have an impact on the Company's financial position or results of operations.

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Item 2.     Management’s Discussion and Analysis of Financial Condition and Results of Operations.

General

Marsh & McLennan Companies, Inc. and its consolidated subsidiaries (the "Company") is a global professional services firm offering clients advice and solutions in risk, strategy and people. It is the parent company of a number of leading risk advisors and specialty consultants, including: Marsh, the insurance broker, intermediary and risk advisor; Guy Carpenter, the risk and reinsurance specialist; Mercer, the provider of HR and Investment related financial advice and services; and Oliver Wyman Group, the management, economic and brand consultancy. With more than 60,000 employees worldwide and annual revenue of more than $13 billion, the Company provides analysis, advice and transactional capabilities to clients in more than 130 countries.

The Company operates through two segments:

• Risk and Insurance Services includes risk management activities (risk advice, risk transfer and risk control and mitigation solutions) as well as insurance and reinsurance broking and services. The Company conducts business in this segment through Marsh and Guy Carpenter.

• Consulting includes wealth, health and career consulting services and products, and specialized management, economic and brand consulting services. The Company conducts business in this segment through Mercer and Oliver Wyman Group.

Effective January 1, 2017, Mercer established a Wealth business reflecting a unified client strategy for its former Retirement and Investments businesses. Wealth is comprised of two practices, Defined Benefit Consulting & Administration (DBA), and Investment Management & Related Services (IMS). DBA encompasses mature businesses primarily in defined benefit and actuarial consulting, along with defined benefit administration. IMS includes businesses primarily in delegated solutions, defined contribution related investment services, and financial wellness. Among the changes, defined benefit investment consulting, previously reported in the Investments business, is now included in Defined Benefit Consulting & Administration. Revenue information is reported for these two practices to provide investors better insight into the underlying growth dynamics within Wealth. This change has no impact on previously reported Mercer total revenue, Consulting segment revenue or operating income, or consolidated revenue or financial results.

A reconciliation of segment operating income to total operating income is included in Note 15 to the consolidated financial statements included in Part I Item 1 in this report. The accounting policies used for each segment are the same as those used for the consolidated financial statements.

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Consolidated Results of Operations

	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share figures)	2017		2016		2017		2016
Revenue	$	3,341	$	3,135	$	10,339	$	9,847
Expense:
Compensation and Benefits	1,906		1,817		5,786		5,543
Other Operating Expenses	838		746		2,383		2,273
Operating Expenses	2,744		2,563		8,169		7,816
Operating Income	597		572		2,170		2,031
Net Income Before Non-Controlling Interests	397		384		1,482		1,354
Net Income Attributable to the Company	$	393	$	379	$	1,463	$	1,332
Net Income Per Share Attributable to the Company:
Basic	$	0.77	$	0.73	$	2.85	$	2.56
Diluted	$	0.76	$	0.73	$	2.81	$	2.54
Average Number of Shares Outstanding:
Basic	512		518		514		520
Diluted	519		523		520		525
Shares Outstanding at September 30	511		516		511		516

The Company's consolidated operating income of $597 million in the third quarter of 2017 increased 4% compared to the prior year period. This reflects the impact of a 7% increase in both revenue and expense. Diluted net income per share attributable to the Company increased 4% when compared to prior year period.

Consolidated operating income was approximately $2.2 billion in the first nine months of 2017, an increase of 7% compared with the first nine months of 2016, reflecting 5% growth in revenue and expenses. Net income attributable to the Company increased 10% reflecting the increase in operating income as well as the impact of a credit to income tax expense related to the required change in accounting for share based awards, partially offset by higher interest expense. Diluted net income per share attributable to the Company increased 11% to $2.81 compared to $2.54 in 2016, reflecting a $131 million increase in net income attributable to the Company as well as a 1% decrease in the average number of diluted shares outstanding.

The number of shares issued related to the vesting of share awards and exercise of employee stock options was more than offset by shares repurchased over the past four quarters. In addition, in accordance with the change in accounting for stock compensation, the excess tax benefits for unvested shares and unexercised stock options are no longer included in the calculation of common stock equivalents ("CSEs") under the Treasury stock method. This had the effect of increasing CSEs by approximately 1.7 million shares.

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Consolidated Revenue and Expense

Revenue - Components of Change

The Company conducts business in more than 130 countries. As a result, foreign exchange rate movements may impact period-to-period comparisons of revenue. Similarly, certain other items such as the revenue impact of acquisitions and dispositions, including transfers among businesses, may impact period-to-period comparisons of revenue. Underlying revenue measures the change in revenue from one period to another by isolating these impacts. The impact of foreign currency exchange fluctuations, acquisitions and dispositions, including transfers among businesses, on the Company’s operating revenues by segment was as follows:

	Three Months Ended September 30,						% Change GAAP Revenue		Components of Revenue Change*
									Currency Impact		Acquisitions/ Dispositions Impact		Underlying Revenue
(In millions)	2017			2016
Risk and Insurance Services
Marsh	$	1,482		$	1,364		9	%	—		6	%	3	%
Guy Carpenter	270			260			4	%	—		—		4	%
Subtotal	1,752			1,624			8	%	—		5	%	3	%
Fiduciary Interest Income	11			8
Total Risk and Insurance Services	1,763			1,632			8	%	—		5	%	3	%
Consulting
Mercer	1,149			1,109			4	%	1	%	3	%	—
Oliver Wyman Group	438			404			8	%	1	%	—		7	%
Total Consulting	1,587			1,513			5	%	1	%	2	%	2	%
Corporate / Eliminations	(9		)	(10		)
Total Revenue	$	3,341		$	3,135		7	%	1	%	3	%	3	%

	Three Months Ended September 30,				% Change GAAP Revenue		Components of Revenue Change*
							Currency Impact		Acquisitions/ Dispositions Impact		Underlying Revenue
(In millions)	2017		2016
Marsh:
EMEA	$	426	$	394	8	%	2	%	8	%	(2	)%
Asia Pacific	164		153		7	%	—		—		7	%
Latin America	95		88		8	%	(3	)%	3	%	9	%
Total International	685		635		8	%	1	%	5	%	2	%
U.S. / Canada	797		729		9	%	—		6	%	3	%
Total Marsh	$	1,482	$	1,364	9	%	—		6	%	3	%
Mercer:
Defined Benefit Consulting & Administration	$	336	$	351	(5	)%	1	%	—		(5	)%
Investment Management & Related Services	194		154		26	%	3	%	14	%	10	%
Total Wealth	530		505		5	%	1	%	4	%	(1	)%
Health	401		397		1	%	1	%	—		—
Career	218		207		5	%	1	%	3	%	2	%
Total Mercer	$	1,149	$	1,109	4	%	1	%	3	%	—

Underlying revenue measures the change in revenue using consistent currency exchange rates, excluding the impact of certain items that affect comparability, such as: acquisitions, dispositions and transfers among businesses and the deconsolidation of Marsh India.
*	Components of revenue change may not add due to rounding.

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	Nine Months Ended September 30,						% Change GAAP Revenue		Components of Revenue Change*
									Currency Impact		Acquisitions/ Dispositions Impact		Underlying Revenue
(In millions)	2017			2016
Risk and Insurance Services
Marsh	$	4,692		$	4,411		6	%	(1	)%	4	%	3	%
Guy Carpenter	948			919			3	%	(1	)%	—		4	%
Subtotal	5,640			5,330			6	%	(1	)%	4	%	3	%
Fiduciary Interest Income	28			20
Total Risk and Insurance Services	5,668			5,350			6	%	(1	)%	4	%	3	%
Consulting
Mercer	3,335			3,227			3	%	(1	)%	2	%	2	%
Oliver Wyman Group	1,370			1,303			5	%	(1	)%	—		6	%
Total Consulting	4,705			4,530			4	%	(1	)%	2	%	3	%
Corporate / Eliminations	(34		)	(33		)
Total Revenue	$	10,339		$	9,847		5	%	(1	)%	3	%	3	%

	Nine Months Ended September 30,				% Change GAAP Revenue		Components of Revenue Change*
							Currency Impact		Acquisitions/ Dispositions Impact		Underlying Revenue
(In millions)	2017		2016
Marsh:
EMEA	$	1,512	$	1,443	5	%	(2	)%	7	%	1	%
Asia Pacific	484		482		1	%	—		(7	)%	7	%
Latin America	274		252		9	%	(1	)%	4	%	7	%
Total International	2,270		2,177		4	%	(2	)%	3	%	3	%
U.S. / Canada	2,422		2,234		8	%	—		5	%	3	%
Total Marsh	$	4,692	$	4,411	6	%	(1	)%	4	%	3	%
Mercer:
Defined Benefit Consulting & Administration	$	1,010	$	1,083	(7	)%	(2	)%	(2	)%	(3	)%
Investment Management & Related Services	572		454		26	%	1	%	15	%	10	%
Total Wealth	1,582		1,537		3	%	(1	)%	3	%	1	%
Health	1,239		1,207		3	%	(1	)%	1	%	2	%
Career	514		483		6	%	(1	)%	3	%	4	%
Total Mercer	$	3,335	$	3,227	3	%	(1	)%	2	%	2	%

Underlying revenue measures the change in revenue using consistent currency exchange rates, excluding the impact of certain items that affect comparability, such as: acquisitions, dispositions and transfers among businesses and the deconsolidation of Marsh India.
*	Components of revenue change may not add due to rounding.

Revenue

Consolidated revenue for the third quarter of 2017 was $3.3 billion, an increase of 7%, or 3% on an underlying basis, with increases of 3% from the impact of acquisitions and 1% from the impact of foreign currency translation.

Revenue in the Risk and Insurance Services segment for the third quarter of 2017 was $1.8 billion, an increase of 8% from the same period last year and 3% on an underlying basis. Consulting revenue of $1.6 billion in the third quarter of 2017 increased 5%, or 2% on an underlying basis.

For the first nine months of 2017, consolidated revenue increased 5% or 3% on an underlying basis. Risk and Insurance Services revenue increased 6% from the same period in 2016, or 3% on an underlying basis. Consulting revenue increased 4% compared with the nine-month period last year, or 3% on an underlying basis.

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Operating Expense

Consolidated operating expense in the third quarter increased 7% compared with the same period last year, reflecting a 2% increase on an underlying basis, a 4% increase from acquisitions, and a 1% increase from the impact of foreign currency translation. The increase in underlying expenses is primarily due to higher base salaries and identified intangible amortization, as well as a charge in 2017 related to the settlement of the final legacy litigation, originally filed in 2006, regarding Marsh's use of market service agreements.

Expenses for the nine months of 2017 increased 5% compared with the same period in 2016, reflecting a 2% increase on an underlying basis and a 4% increase from acquisitions, partly offset by a 1% decrease from the impact of foreign currency translation. The increase in underlying expenses is primarily due to the items discussed above, as well as higher severance related costs, partly offset by lower costs related to liabilities for errors and omissions.

Risk and Insurance Services

The results of operations for the Risk and Insurance Services segment are presented below:

For the Three and Nine Months Ended September 30,	Three Months						Nine Months
(In millions)	2017			2016			2017			2016
Revenue	$	1,763		$	1,632		$	5,668		$	5,350
Compensation and Benefits	999			924			2,947			2,779
Other Expenses	450			393			1,266			1,231
Expense	1,449			1,317			4,213			4,010
Operating Income	$	314		$	315		$	1,455		$	1,340
Operating Income Margin	17.8		%	19.2		%	25.7		%	25.0		%

Revenue

Revenue in the Risk and Insurance Services segment in the third quarter of 2017 was $1.8 billion, an increase of 8% as compared to the same period last year, reflecting a 3% increase in underlying revenue and a 5% increase related to acquisitions, while the impact of foreign currency translation was flat.

In Marsh, revenue in the third quarter of 2017 was $1.5 billion, an increase of 9% compared with the same quarter of the prior year, reflecting an increase in underlying revenue of 3% and a 6% increase from acquisitions. Revenue in international operations grew 2% on an underlying basis, with growth of 7% in Asia Pacific and 9% in Latin America, partly offset by a decrease of 2% in EMEA. In U.S./Canada, underlying revenue increased 3% compared to prior year. Guy Carpenter's third quarter revenue increased 4% on both a reported and underlying basis.

Revenue in the Risk and Insurance Services segment increased 6% in the first nine months of 2017 compared with 2016, or 3% on an underlying basis. In Marsh, underlying revenue increased 3% in U.S./Canada. The international division increased 3% on an underlying basis, reflecting a 1% increase in EMEA, a 7% increase in Asia Pacific and a 7% increase in Latin America.

Expense

Expenses in the Risk and Insurance Services segment increased 10% in the third quarter of 2017 compared with the same period last year, reflecting increases of 4% in underlying expenses, 5% related to acquisitions, and 1% from the impact of foreign currency translation. The increase in underlying expenses is primarily due to higher base salaries, incentive compensation costs and identified intangible amortization, as well as a charge in 2017 related to the settlement of the final legacy litigation, originally filed in 2006, regarding Marsh's use of market service agreements.

Expenses for the nine month period of 2017 increased 5% compared to the prior year, reflecting increases of 2% in underlying expenses and 4% related to acquisitions, partly offset by a 1% decrease from the impact of foreign currency translation. The underlying expense increase is primarily due to the items discussed above, partly offset by lower contingent consideration related to acquisitions and lower costs related to liabilities for errors and omissions.

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Consulting

The results of operations for the Consulting segment are presented below:

For the Three and Nine Months Ended September 30,	Three Months						Nine Months
(In millions)	2017			2016			2017			2016
Revenue	$	1,587		$	1,513		$	4,705		$	4,530
Compensation and Benefits	825			807			2,583			2,506
Other Expenses	433			398			1,269			1,186
Expense	1,258			1,205			3,852			3,692
Operating Income	$	329		$	308		$	853		$	838
Operating Income Margin	20.7		%	20.4		%	18.1		%	18.5		%

Revenue

Revenue in the Consulting segment in the third quarter of 2017 was $1.6 billion, an increase of 5% compared to the same period last year, reflecting a 2% increase in underlying revenue, a 2% increase related to acquisitions and a 1% increase from the impact of foreign currency translation.

Effective January 1, 2017, Mercer established a Wealth business reflecting a unified client strategy for its former Retirement and Investments businesses.

Mercer's revenue of approximately $1.1 billion increased 4% compared to the prior year on a reported basis, and was flat on an underlying basis. On an underlying basis, revenue in Career increased 2% while Health was flat and Wealth decreased 1%. Within Wealth, Investment Management & Related Services increased 10% and Defined Benefit Consulting & Administration decreased 5% compared to the same period last year. Oliver Wyman's revenue increased 8% to $438 million in the third quarter of 2017 compared to the same period last year, reflecting a 7% increase on an underlying basis and a 1% increase from the impact of foreign currency translation.

Consulting revenue in the first nine months of 2017 increased 4%. Underlying revenue increased 3% with underlying growth of 2% at Mercer and 6% at Oliver Wyman.

Expense

Consulting expenses in the third quarter of 2017 increased 4% as compared to the third quarter of 2016. This reflects increases of 3% from acquisitions and 1% from the impact of foreign currency translation. Underlying expense increased 1% in the third quarter of 2017 compared to the same period in 2016, reflecting the impact of higher base salaries, higher asset based fees and outside service costs, partly offset by lower incentive compensation costs.

Underlying expenses for the nine months of 2017 increased 2% as compared to 2016, primarily due to the items discussed above, higher severance costs related to the Mercer business restructuring, partly offset by lower costs related to liabilities for errors and omissions.

Corporate and Other

Corporate expenses were $46 million and $51 million for the third quarter of 2017 and 2016, respectively. For the first nine months of 2017, corporate expenses were $138 million compared with $147 million for the same period last year. The decrease in expenses is primarily due to lower outside service and occupancy costs.

Interest

Interest income earned on corporate funds was $2 million in the third quarter of 2017 compared with less than $1 million for the same period in 2016, and $6 million for the nine month periods of 2017 compared to $4 million for the same period in 2016. Interest expense increased $13 million in the third quarter of 2017 compared with the third quarter of 2016 and increased $37 million for the nine months of 2017 compared with the same period last year. The increase in interest expense is primarily due to higher average debt outstanding in 2017.

Investment Income (Loss)

The caption "Investment income (loss)" in the consolidated statements of income comprises realized and unrealized gains and losses from investments. It includes, when applicable, other-than-temporary declines in the value of debt and available-for-sale securities and equity method gains or losses on its investments in private equity funds. The

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Company's investments may include direct investments in insurance, consulting or other strategically linked companies and investments in private equity funds. The Company had a net investment loss of $2 million in the third quarter of 2017 compared to a net investment gain of less than $1 million for the same period in 2016. For the first nine months of 2017, the Company recorded net investment income of $3 million compared to a net investment loss of $2 million for the nine months of 2016.

Income Taxes

The Company's effective tax rate in the third quarter of 2017 was 26.2% compared to 26.8% in the third quarter of 2016. The effective tax rate for the first nine months of 2017 was 25.9% compared with 28.4% for the first nine months of 2016. The rates reflect foreign operations taxed at rates below the U.S. statutory tax rate, including the effect of repatriation, as well as the impact of discrete tax matters such as tax legislation, changes in valuation allowances, non-taxable adjustments to contingent acquisition consideration and, starting in 2017, excess tax benefits related to share-based compensation. The excess tax benefit related to share based payments is the most significant discrete item, reducing the effective tax rate by 1.9% in the third quarter of 2017 and 2.9% for the nine months of 2017.

The effective tax rate is sensitive to the geographic mix and repatriation of the Company's earnings, which may result in higher or lower tax rates. U.S. federal and state corporate tax rates substantially exceed tax rates applicable in most jurisdictions outside the U.S. A significant portion of the Company's profits are earned outside the U.S. In 2017, the forecasted pre-tax income in the U.K., Barbados, Canada, Australia, and Germany, is expected to account for approximately 60% of the Company's total non-U.S. pre-tax income, with estimated effective tax rates in those countries of 23%, 0.3%, 27%, 30%, and 32%, respectively. Consequently, continued improvement in the profitability of the Company's U.S.-based operations would tend to result in higher effective tax rates. Losses in one jurisdiction, generally, cannot offset earnings in another, and within certain jurisdictions profits and losses may not offset between entities. Consequently, losses in certain jurisdictions may require valuation allowances affecting the effective tax rate, depending on estimates of the realizability of associated deferred tax assets. The tax rate is also sensitive to changes in unrecognized tax benefits, including the impact of settled tax audits and expired statutes of limitation.

Changes in tax laws or tax rulings may have a significant impact on our effective tax rate. Discussions continue within Congress and the Administration about broad reform of the corporate tax system in the U.S. It is not possible to predict the ultimate outcome of these discussions. Future legislation could have a material impact on our effective tax rate and consolidated financial statements due to reforms that could include changes in the corporate tax rate, changes in the way U.S. corporations are taxed on foreign earnings and eliminations of certain corporate deductions.

The Company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in tax returns. The Company's gross unrecognized tax benefits decreased from $65 million at December 31, 2016 to $64 million at September 30, 2017 due to settlements of audits and expirations of statutes of limitation, partially offset by current accruals. It is reasonably possible that the total amount of unrecognized tax benefits will decrease between zero and approximately $9 million within the next twelve months due to settlements of audits and expirations of statutes of limitation.

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Liquidity and Capital Resources

The Company is organized as a legal entity separate and distinct from its operating subsidiaries. As the Company does not have significant operations of its own, the Company is dependent upon dividends and other payments from its operating subsidiaries to pay principal and interest on its outstanding debt obligations, pay dividends to stockholders, repurchase its shares and pay corporate expenses. The Company also provides financial support to its operating subsidiaries for acquisitions, investments and certain parts of their business that require liquidity, such as the capital markets business of Guy Carpenter. Other sources of liquidity include borrowing facilities discussed below in Financing Cash Flows.

The Company derives a significant portion of its revenue and operating profit from operating subsidiaries located outside of the United States. Funds from those operating subsidiaries are regularly repatriated to the United States out of annual earnings. At December 31, 2016, the Company had approximately $850 million of cash and cash equivalents in its foreign operations, substantially all of which is considered to be permanently invested in those operations to fund foreign investments and working capital needs. The $850 million of non-U.S. cash and cash equivalents considered permanently reinvested includes $169 million of operating funds required to be maintained for regulatory requirements or as collateral under certain captive insurance arrangements. The Company expects to continue its practice of repatriating foreign funds from its non-U.S. operating subsidiaries out of current annual earnings. While management does not foresee a need to repatriate the funds which are currently deemed permanently invested, if facts or circumstances change, management could elect to repatriate them, if necessary, which could result in higher effective tax rates in the future. In the first nine months of 2017, the Company recorded foreign currency translation adjustments which increased net equity by approximately $650 million.

Cash and cash equivalents on our consolidated balance sheets includes funds available for general corporate purposes. Funds held on behalf of clients in a fiduciary capacity are segregated and shown separately in the consolidated balance sheets as an offset to fiduciary liabilities. Fiduciary funds cannot be used for general corporate purposes, and should not be considered as a source of liquidity for the Company.

Operating Cash Flows

The Company generated $1.1 billion of cash from operations for both nine month periods ended September 30, 2017 and 2016. These amounts reflect the net income of the Company during those periods, excluding gains or losses from investments, adjusted for non-cash charges and changes in working capital which relate primarily to the timing of payments of accrued liabilities and pension plan contributions or receipts of assets.

Pension Related Items

Contributions

The Company's policy for funding its tax-qualified defined benefit plans is to contribute amounts at least sufficient to meet the funding requirements set forth in the applicable laws or regulations of the U.S. and other jurisdictions. During the first nine months of 2017, the Company contributed $166 million to its non-U.S. defined benefit pension plans and $27 million to its U.S. defined benefit pension plans. In the first nine months of 2016, the Company contributed $139 million to its non-U.S. defined benefit pension plans and $20 million to its U.S. defined benefit pension plans.

In the U.S., contributions to the tax-qualified defined benefit plans are based on ERISA guidelines and the Company generally expects to maintain a funded status of 80% or more of the liability determined under the ERISA guidelines.

Outside the U.S., the Company has a large number of defined benefit pension plans, the largest of which are in the U.K., which comprise approximately 81% of non-U.S. plan assets at December 31, 2016. Contribution rates for non-U.S. plans are generally based on local funding practices and statutory requirements, which may differ significantly from measurements under U.S. GAAP. In the U.K., the assumptions used to determine pension contributions are the result of legally-prescribed negotiations between the Company and the plans' trustee that typically occur every three years in conjunction with the actuarial valuation of the plans. Currently, this results in a lower funded status than under U.S. GAAP and may result in contributions irrespective of the U.S. GAAP funded status. In November 2016, the Company and the Trustee of the U.K. Defined Benefits Plans agreed to a funding deficit recovery plan for the U.K. defined benefit pension plans. The current agreement with the Trustee sets out the annual deficit contributions which would be due based on the deficit at December 31, 2015. The funding level is subject to re-assessment, in most cases on November 1 of each year. If the funding level on November 1 is sufficient, no deficit funding contributions will be required in the following year, and the contribution amount will be deferred. As part of a long-term strategy, which depends on having greater influence over asset allocation and overall investment

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decisions, in November 2016 the Company renewed its agreement to support annual deficit contributions by the U.K. operating companies under certain circumstances, up to GBP 450 million over a seven-year period.

The Company expects to fund an additional $58 million to its non-U.S. defined benefit plans over the remainder of 2017, comprising approximately $27 million to plans outside of the U.K. and $31 million to the U.K. plans. The Company also expects to fund an additional $5 million to its U.S. defined benefit plans during the remainder of 2017.

Funding amounts may be influenced by future asset performance, the level of discount rates and other variables impacting the funded status of the plan.

Changes in Pension Plans

The Company continues to manage the cost and assess the competitiveness of its benefits programs, and also to manage the risks related to its defined benefit pension plan liabilities. In October 2016, the Company modified its U.S. defined benefit pension plans to discontinue further benefit accruals for participants after December 31, 2016. At the same time, the Company amended its U.S. defined contribution retirement plans for most of its U.S. employees to add an automatic Company contribution equal to 4% of eligible base pay beginning on January 1, 2017. This new Company contribution, together with the Company’s current matching contribution, provides eligible U.S. employees with the opportunity to receive a total contribution of up to 7% of eligible base pay. As required under GAAP, the defined benefit plans that were significantly impacted by the modification were re-measured in October 2016 using market data and assumptions as of the modification date. The net periodic pension expense recognized in 2016 reflects the weighted average costs of the December 31, 2015 measurement and the October 2016 re-measurement. In addition, the U.S. qualified plans were merged effective December 30, 2016.

In March 2017, the Company modified its defined benefit pension plans in Canada to discontinue further benefit accruals for participants after December 31, 2017 and replaced them with a defined contribution arrangement. The Company also amended its post-retirement benefits plan in Canada so that individuals who retire after April 1, 2019 will not be eligible to participate, except in certain situations. The Company re-measured the assets and liabilities of the plans, based on assumptions and market conditions on the amendment date.

The Defined Benefit Pension Plans in the U.K. allow participants an option for the payment of a lump sum distribution from plan assets before retirement in full satisfaction of the retirement benefits due to the participant as well as any survivor’s benefit. The Company’s policy under applicable U.S. GAAP is to treat these lump sum payments as a partial settlement of the plan liability if they exceed the sum of service cost plus interest cost components of net period pension cost of a plan for the year ("settlement thresholds"). Based on the amount of lump sum payments through September 30, 2017, plus estimates of projected lump sum payments through December 31, 2017, it is likely the lump sum payments will exceed the settlement thresholds in one or more of the U.K. plans. If the settlement thresholds are reached in the fourth quarter in one or more of the plans, we expect it will result in a non-cash settlement charge of $30-$50 million or more. The amount of the charge will depend on the actual participant elections for lump sum settlements paid through December 31, 2017.

Financing Cash Flows

Net cash used for financing activities was $527 million for the nine-month period ended September 30, 2017, compared with $783 million net cash used by such activities for the same period in 2016.

Debt

The Company has established a short-term debt financing program of up to $1.5 billion through the issuance of commercial paper. The proceeds from the issuance of commercial paper are used for general corporate purposes. The Company had no commercial paper outstanding at September 30, 2017.

In January 2017, the Company issued $500 million of 2.75% senior notes due in 2022 and $500 million of 4.35% senior notes due in 2047. The Company used the net proceeds for general corporate purposes, which included the repayment of $250 million of senior notes in April 2017.

In March 2016, the Company issued $350 million of 3.30% seven-year senior notes. The Company used the net proceeds for general corporate purposes.

Credit Facilities

The Company and certain of its subsidiaries maintain a $1.5 billion multi-currency five-year unsecured revolving credit facility. The interest rate on this facility is based on LIBOR plus a fixed margin which varies with the Company's credit ratings. This facility expires in November 2020 and requires the Company to maintain certain

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coverage and leverage ratios which are tested quarterly. There were no borrowings outstanding under this facility at September 30, 2017.

The Company's senior debt is currently rated A- by Standard & Poor's and Baa1 by Moody's. The Company's short-term debt is currently rated P-2 by Moody's and A-2 by Standard & Poor's. The Company carries a stable outlook from Moody's and Standard & Poor's.

Share Repurchases

During the first nine months of 2017, the Company repurchased 8.0 million shares of its common stock for total consideration of $600 million at an average price per share of $75.44. In November 2016, the Board of Directors authorized an increase in the Company’s share repurchase program, which supersedes any prior authorization, allowing management to buy back up to $2.5 billion of the Company’s common stock going forward. As of September 30, 2017, the Company remained authorized to purchase shares of its common stock up to a value of approximately $1.8 billion. There is no time limit on this authorization.

During the first nine months of 2016, the Company repurchased approximately 10.0 million shares of its common stock for consideration of $625 million.

Contingent payments related to acquisitions

During the first nine months of 2017, the Company paid $107 million of contingent payments related to acquisitions made in prior periods. These payments are split between financing and operating cash flows in the consolidated statements of cash flows. Payments of $80 million related to the contingent consideration liability that was recorded on the date of acquisition are reflected as financing cash flows. Payments related to increases in the contingent consideration liability subsequent to the date of acquisition of $27 million are reflected as operating cash flows. Remaining estimated future contingent consideration payments of $170 million for acquisitions completed in the first nine months of 2017 and in prior years are recorded in accounts payable and accrued liabilities or other liabilities in the consolidated balance sheet at September 30, 2017.

The Company paid deferred purchase consideration related to prior years' acquisitions of $47 million in the first nine months of 2017. Remaining deferred cash payments of approximately $126 million for acquisitions completed in the first nine months of 2017 and in prior years are recorded in accounts payable and accrued liabilities or other liabilities in the consolidated balance sheet at September 30, 2017.

In the first nine months of 2016, the Company paid $85 million of contingent payments related to acquisitions made in prior periods. Of this amount, $43 million was reported as financing cash flows and $42 million as operating cash flows.

Dividends

The Company paid dividends on its common shares of $545 million ($1.055 per share) during the first nine months of 2017, as compared with $504 million ($0.96 per share) during the first nine months of 2016.

Investing Cash Flows

Net cash used for investing activities amounted to $859 million in the first nine months of 2017, compared with $258million used during the same period in 2016.

The Company paid $629 million and $88 million, net of cash acquired, for acquisitions it made during the first nine months of 2017 and 2016, respectively.

The Company used cash of $217 million to purchase fixed assets and capitalized software in the first nine months of 2017, compared with $174 million in the first nine months of 2016, primarily related to computer equipment and software purchases, software development costs and the refurbishing and modernizing of office facilities.

The Company has commitments for potential future investments of approximately $65 million in five private equity funds that invest primarily in financial services companies.

41

Commitments and Obligations

The Company’s contractual obligations of the types identified in the table below were of the following amounts as of September 30, 2017:

(In millions of dollars)	Payment due by Period
Contractual Obligations	Total		Within 1 Year		1-3 Years		4-5 Years		After 5 Years
Short-term debt	$	13	13		—		—		—
Long-term debt	5,512		—		1,077		1,030		3,405
Interest on long-term debt	1,959		206		387		325		1,041
Net operating leases	1,928		309		508		397		714
Service agreements	234		138		90		6		—
Other long-term obligations	324		107		209		5		3
Total	$	9,970	$	773	$	2,271	$	1,763	$	5,163

The above does not include unrecognized tax benefits of $64 million, in accordance with FASB guidance on accounting for uncertain tax positions, as the Company is unable to reasonably predict the timing of settlement of these liabilities, other than approximately $3 million that may become payable within one year. The above does not include the indemnified liabilities discussed in Note 14 as the Company is unable to reasonably predict the timing of settlement of those liabilities. The above does not include net pension liabilities for underfunded plans of approximately $1.8 billion because the timing and amount of ultimate payment of such liability is dependent upon future events, including, but not limited to, future returns on plan assets and changes in the discount rate used to measure the liabilities. The Company expects to contribute approximately $5 million and $58 million to its U.S. and non-U.S. pension plans, respectively, in the remainder of 2017.

New Accounting Guidance

Note 16 to the consolidated financial statements in this report contains a discussion of recently issued accounting guidance and their impact or potential future impact on the Company’s financial results, if determinable.

42

Item 3. Quantitative and Qualitative Disclosures About Market Risk.

Market Risk and Credit Risk

Certain of the Company’s revenues, expenses, assets and liabilities are exposed to the impact of interest rate changes and fluctuations in foreign currency exchange rates and equity markets.

The Company had the following investments subject to variable interest rates:

(In millions)	September 30, 2017
Cash and cash equivalents invested in money market funds, certificates of deposit and time deposits	$	1,078
Fiduciary cash and investments	$	5,128

Based on the above balances, if short-term interest rates increased or decreased by 10%, or 10 basis points, for the remainder of the year, annual interest income, including interest earned on fiduciary funds, would increase or decrease by approximately $2 million.

Changes in interest rates can also affect the discount rate and assumed rate of return on plan assets, two of the assumptions among several others used to measure net periodic pension expense. The assumptions used to measure plan assets and liabilities are typically assessed at the end of each year, and determine the expense for the subsequent year. Assumptions used to determine net periodic expense for 2017 are discussed in Note 8 to the consolidated financial statements included in our most recently filed Annual Report on Form 10-K. For a discussion on pension expense sensitivity to changes in these rates, see the "Management’s Discussion and Analysis of Financial Condition and Results of Operations-Management’s Discussion of Critical Accounting Policies-Retirement Benefits" section of our most recently filed Annual Report on Form 10-K.

In addition to interest rate risk, our cash and cash equivalents and fiduciary fund investments are subject to potential loss of value due to counter-party credit risk. To minimize this risk, the Company and its subsidiaries invest pursuant to a Board-approved investment policy. The policy mandates the preservation of principal and liquidity and requires broad diversification with counter-party limits assigned based primarily on credit rating and type of investment. The Company carefully monitors its cash and fiduciary fund investments and will further restrict the portfolio as appropriate in response to market conditions. The majority of cash and fiduciary fund investments are invested in short-term bank deposits.

Foreign Currency Risk

The translated values of revenue and expense from the Company’s international operations are subject to fluctuations due to changes in currency exchange rates. The non-U.S. based revenue that is exposed to foreign exchange fluctuations is approximately 50% of total revenue. We periodically use forward contracts and options to limit foreign currency exchange rate exposure on net income and cash flows for specific, clearly defined transactions arising in the ordinary course of business. Although the Company has significant revenue generated in foreign locations which is subject to foreign exchange rate fluctuations, in most cases both the foreign currency revenue and expenses are in the functional currency of the foreign location. As such, under normal circumstances, the U.S. dollar translation of both the revenues and expenses, as well as the potentially offsetting movements of various currencies against the U.S. dollar, generally tends to mitigate the impact on net operating income of foreign currency risk. However, there have been periods where the impact was not mitigated due to external market factors and events, such as the decision in the United Kingdom to exit the European Union. Similar macroeconomic events may result in greater foreign exchange rate fluctuations in the future. If foreign exchange rates of major currencies (Euro, Sterling, Australian dollar and Canadian dollar) moved 10% in the same direction against the U.S. dollar compared with the foreign exchange rates in 2016, the Company estimates net operating income would increase or decrease by approximately $59 million. The Company has exposure to approximately 80 foreign currencies overall. If exchange rates at September 30, 2017 hold constant for the rest of 2017, the Company estimates the year-over-year impact from conversion of foreign currency earnings will increase full year net operating income by approximately $7 million.

Equity Price Risk

The Company holds investments in both public and private companies as well as private equity funds. Investments of approximately $115 million are classified as available for sale, which includes the Company's investment in Benefitfocus. Approximately $61 million are accounted for using the cost method and $405 million are accounted for using the equity method, including the Company's investment in Alexander Forbes. The investments are subject to

43

risk of decline in market value, which, if determined to be other than temporary, could result in realized impairment losses. The Company periodically reviews the carrying value of such investments to determine if any valuation adjustments are appropriate under the applicable accounting pronouncements.

As of September 30, 2017, the carrying value of the Company’s investment in Alexander Forbes was $268 million. As of September 30, 2017, the market value of the approximately 443 million shares of Alexander Forbes owned by the Company, based on the September 30, 2017 closing share price of 6.75 South African Rand per share, was approximately $225 million. The Company considered several factors in assessing its investment in Alexander Forbes for impairment, including its financial position, the near- and long-term prospects of Alexander Forbes and the broader South African economy and capital markets, the length of time and extent to which the market value was below cost and the Company’s intent and ability to retain the investment for a sufficient period of time to allow for anticipated recovery in market value. During the first nine months of 2017, the daily closing price ranged from a high of 7.89 Rand (in early January) to a low of 5.99 Rand (in late April). During the third quarter of 2017, the Alexander Forbes average opening and closing stock price was approximately 6.75 Rand (approximately 90% of the original purchase price) and ranged from 6.40 Rand to 7.28 Rand (approximately 85% to 97% of the purchase price). Based on its assessment of the factors discussed above, the Company determined the investment was not impaired.

Other

A number of lawsuits and regulatory proceedings are pending. See Note 14 ("Claims, Lawsuits and Other Contingencies") to the consolidated financial statements in this report.

44

Item 4. Controls & Procedures.

a. Evaluation of Disclosure Controls and Procedures

Based on their evaluation, as of the end of the period covered by this report, the Company’s Chief Executive Officer and Chief Financial Officer have concluded that the Company’s disclosure controls and procedures (as defined in Rules 13a-15(e) or 15d-15(e) under the Securities Exchange Act of 1934) are effective.

b. Changes in Internal Control

There were no changes in the Company’s internal control over financial reporting identified in connection with the evaluation required by Rules 13a-15(d) or 15d-15(d) under the Securities Exchange Act of 1934 that occurred during the Company’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

45

PART II. OTHER INFORMATION

Item 1.        Legal Proceedings.

In April 2017, the Financial Conduct Authority in the United Kingdom (the "FCA") commenced a civil competition investigation into the aviation insurance and reinsurance sector. In connection with that investigation, the FCA carried out an on-site inspection at the London office of Marsh Limited, our Marsh and Guy Carpenter operating subsidiary in the United Kingdom. The FCA indicated that it had reasonable grounds for suspecting that Marsh Limited and other participants in the market have been sharing competitively sensitive information within the aviation insurance and reinsurance broking sector.

In October 2017, the Company received a notice that the Directorate-General for Competition of the European Commission had commenced a civil investigation of a number of insurance brokers, including Marsh, regarding "the exchange of commercially sensitive information between competitors in relation to aviation and aerospace insurance and reinsurance broking products and services in the European Economic Area ("EEA"), as well as possible coordination between competitors." In light of the action taken by the European Commission, the FCA informed Marsh Limited at the same time that it has discontinued its investigation under U.K. competition law into the aviation insurance and reinsurance sector.

In July 2017, the Directorate-General for Competition of the European Commission together with the Irish Competition and Consumer Protection Commission conducted on-site inspections at the offices of Marsh and other industry participants in Dublin in connection with an investigation regarding the "possible participation in anticompetitive agreements and/or concerted practices contrary to [E.U. competition law] in the market for commercial motor insurance in the Republic of Ireland."

We are cooperating with these investigations and are conducting our own reviews. As these investigations are at early stages, we are unable to predict their likely timing, outcome or ultimate impact. There can be no assurance that the ultimate resolution of these or any related matters will not have a material adverse effect on our consolidated results of operations, financial condition or cash flows.

We and our subsidiaries are also party to a variety of other legal, administrative, regulatory and government proceedings, claims and inquiries arising in the normal course of business. Additional information regarding certain legal proceedings and related matters is set forth in Note 14 to the consolidated financial statements provided in Part I of this report is incorporated herein by reference.

Item 1A.     Risk Factors.

The Company and its subsidiaries face a number of risks and uncertainties. In addition to the other information in this report and our other filings with the SEC, readers should consider carefully the risk factors discussed in "Part I, Item 1A. Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2016. If any of the risks described in our Annual Report on Form 10-K or such other risks actually occur, our business, results of operations or financial condition could be materially adversely affected.

46

Item 2.         Unregistered Sales of Equity Securities and Use of Proceeds.

Issuer Repurchases of Equity Securities

The Company repurchased approximately 2.6 million shares of its common stock for $200 million during the third quarter of 2017. In November 2016, the Board of Directors of the Company authorized the Company to repurchase up to $2.5 billion in shares of the Company's common stock, which superseded any prior authorizations. As of September 30, 2017, the Company remained authorized to repurchase up to approximately $1.8 billion in shares of its common stock. There is no time limit on the authorization.

Period	(a) Total Number of Shares (or Units) Purchased	(b) Average Price Paid per Share (or Unit)		(c) Total Number of Shares (or Units) Purchased as Part of Publicly Announced Plans or Programs	(d) Maximum Number (or Approximate Dollar Value) of Shares (or Units) that May Yet Be Purchased Under the Plans or Programs
July 1-31, 2017	914,641	$	78.4382	914,641	$	1,969,009,378
August 1-31, 2017	1,272,689	$	77.8602	1,272,689	$	1,869,917,605
September 1-30, 2017	361,716	$	80.3440	361,716	$	1,840,855,893
Total	2,549,046	$	78.4200	2,549,046	$	1,840,855,893

Item 3.         Defaults Upon Senior Securities.

None.

Item 4.         Mine Safety Disclosure.

Not Applicable.

Item 5.         Other Information.

None.

Item 6.         Exhibits.

See the Exhibit Index immediately following the signature page of this report, which is incorporated herein by reference.

47

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Date:	October 27, 2017	/s/ Mark C. McGivney
		Mark C. McGivney
		Chief Financial Officer
Date:	October 27, 2017	/s/ Robert J. Rapport
		Robert J. Rapport
		Senior Vice President & Controller
		(Chief Accounting Officer)

48

EXHIBIT INDEX

Exhibit No.	Exhibit Name
10.1	Letter Agreement, effective as of February 22, 2017, between Marsh & McLennan Companies, Inc. and Daniel S. Glaser
10.2	Letter Agreement, effective as of July 12, 2017, between Marsh & McLennan Companies, Inc. and Julio A. Portalatin
12.1	Statement Re: Computation of Ratio of Earnings to Fixed Charges
31.1	Rule 13a-14(a)/15d-14(a) Certification of Chief Executive Officer
31.2	Rule 13a-14(a)/15d-14(a) Certification of Chief Financial Officer
32.1	Section 1350 Certifications
101.INS	XBRL Instance Document
101.SCH	XBRL Taxonomy Extension Schema
101.CAL	XBRL Taxonomy Extension Calculation Linkbase
101.DEF	XBRL Taxonomy Extension Definition Linkbase
101.LAB	XBRL Taxonomy Extension Label Linkbase
101.PRE	XBRL Taxonomy Extension Presentation Linkbase

49

EX-10.1

Steven A. Mills Chairman of the Compensation Committee of the Board of Directors Marsh & McLennan Companies, Inc. 1166 Avenue of the Americas New York, New York 10036 www.mmc.com

Exhibit 10.1

September 19, 2017

Daniel S. Glaser

[Address]

[City, State, Zip Code]

Subject:    Terms of Employment

Dear Dan:

This third amendment to the letter agreement, dated September 18, 2013, between you and Marsh & McLennan Companies, Inc., as amended by the first amendment dated June 11, 2014 and second amendment dated May 18, 2016 (collectively, the "Letter Agreement"), revises the terms and conditions of your employment as follows:

1. Exhibit A to the Letter Agreement shall be deleted and replaced in its entirety with the attached Exhibit A.

The terms of this third amendment are effective as of February 22, 2017. Except as amended by this third amendment, the Letter Agreement will continue to govern your employment as the President and Chief Executive Officer of Marsh & McLennan Companies, Inc.

Please acknowledge your agreement with the terms of the Letter Agreement, as amended by this third amendment, by signing and dating this and the enclosed copy of this third amendment and returning it to me.

Sincerely,

/s/ Steven A. Mills

Steven A. Mills

Chairman of the Compensation Committee of the Board of Directors

Marsh & McLennan Companies, Inc.

Accepted and Agreed:

/s/ Daniel S. Glaser    

(Signature)        

9/19/17        

(Date)

September 19, 2017

Daniel S. Glaser

Page 2

Exhibit A

Board or Committee Memberships	• International Advisory Board of BritishAmerican Business • Board of Trustees of The Institutes • Board of Trustees of Ohio Wesleyan University
Annual Base Salary	$1,400,000
Annual Target Bonus Opportunity	Bonus awards are discretionary. Target bonus of $2,800,000. Actual bonus may range from 0% - 200% of target, based on achievement of individual performance objectives, and/or Marsh & McLennan Companies’ performance as Marsh & McLennan Companies may establish from time to time.
Annual Target Long-Term Incentive Opportunity	Long-term incentive awards are discretionary. Target award of $9,500,000 (based on grant date fair value).
Other Benefits	• You will have access to a car and driver for business purposes and for work/home travel purposes. • You will have access to corporate aircraft for personal travel, up to $130,000 in aggregate incremental cost each calendar year, commencing with the 2017 calendar year, as calculated by the Company for disclosure purposes for the Summary Compensation Table of the Company’s Proxy Statement; provided that this amount and calculation methodology will be reviewed from time to time and subject to adjustment to reflect market trends. The Company currently calculates incremental cost by adding the incremental variable costs associated with personal flights on the aircraft (including hourly charges, taxes, passenger fees, international fees and catering). If the imputed income attributable to these benefits is taxable to you, then the taxes associated with this taxable income will not be reimbursed or paid by the Company.

EX-10.2

Daniel S. Glaser President and Chief Executive Officer Marsh & McLennan Companies, Inc. 1166 Avenue of the Americas New York, New York 10036 212 345 4874 Fax 212 345 6676 dan.glaser@mmc.com www.mmc.com

Exhibit 10.2

September 14, 2017

Julio A. Portalatin

[Address]

[City, State Zip Code]

Subject:Terms of Employment

Dear Julio:

This third amendment to the letter agreement, dated November 21, 2013, between you and Marsh & McLennan Companies, Inc., as amended by the first amendment dated June 6, 2014 and second amendment dated June 10, 2016 (collectively, the "Letter Agreement:), revises the terms and conditions of your employment as follows:

1. Exhibit A to the Letter Agreement shall be deleted and replaced in its entirety with the attached Exhibit A.

The terms of this third amendment are effective as of July 12, 2017. Except as amended by this third amendment, the Letter Agreement will continue to govern your employment as the President and Chief Executive Officer of Mercer Consulting Group, Inc.

Please acknowledge your agreement with the terms of the Letter Agreement, as amended by this third amendment, by signing and dating this and the enclosed copy of this third amendment and returning it to me.

Sincerely,

/s/ Daniel S. Glaser

Daniel S. Glaser

President and Chief Executive Officer

Marsh & McLennan Companies, Inc.

Accepted and Agreed:

/s/ Julio A. Portalatin

(Signature)                

9/19/17    

(Date)

September 14, 2017

Julio A. Portalatin

Page 2

Exhibit A

Board or Committee Memberships	• Board of Directors of DXC Technology • Hofstra University Board of Trustees
Annual Base Salary	$1,000,000, effective August 1, 2017
Annual Target Bonus Opportunity	Bonus awards are discretionary. Target bonus of $2,250,000 commencing with the 2017 performance year (awarded in 2018). Actual bonus may range from 0% - 200% of target, based on achievement of individual performance objectives, Mercer’s performance and/or Marsh & McLennan Companies’ performance as Marsh & McLennan Companies may establish from time to time.
Annual Target Long-Term Incentive Opportunity	Long-term incentive awards are discretionary. Target award of $2,500,000 (based on grant date fair value).

EX-12.1

Exhibit 12.1

Marsh & McLennan Companies, Inc. and Subsidiaries

Ratio of Earnings to Fixed Charges

(In millions, except ratios)

	Nine Months Ended September 30, 2017		Years Ended December 31,
	(Unaudited)			2016		2015		2014		2013		2012
Earnings
Income before income taxes	$	2,001		$	2,480	$	2,307	$	2,057	$	1,973	$	1,696
Interest expense	178			189		163		165		167		181
Portion of rents representative of the interest factor	84			122		127		131		134		139
	$	2,263		$	2,791	$	2,597	$	2,353	$	2,274	$	2,016
Fixed Charges
Interest expense	$	178		$	189	$	163	$	165	$	167	$	181
Portion of rents representative of the interest factor	84			122		127		131		134		139
	$	262		$	311	$	290	$	296	$	301	$	320
Ratio of Earnings to Fixed Charges	8.6			9.0		9.0		7.9		7.6		6.3

EX-31.1

Exhibit 31.1

CERTIFICATIONS

I, Daniel S. Glaser, certify that:

1. I have reviewed this quarterly report on Form 10-Q of Marsh & McLennan Companies, Inc. (the “registrant”);

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	October 27, 2017	/s/ Daniel S. Glaser
		Daniel S. Glaser
		President and Chief Executive Officer

EX-31.2

Exhibit 31.2

CERTIFICATIONS

I, Mark C. McGivney, certify that:

1. I have reviewed this quarterly report on Form 10-Q of Marsh & McLennan Companies, Inc. (the “registrant”);

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	October 27, 2017	/s/ Mark C. McGivney
		Mark C. McGivney
		Chief Financial Officer

EX-32.1

Exhibit 32.1

Certification of Chief Executive Officer and Chief Financial Officer

The certification set forth below is being submitted in connection with the Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2017 of Marsh & McLennan Companies, Inc. (the "Report") for the purpose of complying with Rule 13a-14(b) or Rule 15d-14(b) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and Section 1350 of Chapter 63 of Title 18 of the United States Code.

Daniel S. Glaser, the President and Chief Executive Officer, and Mark C. McGivney, Chief Financial Officer, of Marsh & McLennan Companies, Inc. each certifies that, to the best of his knowledge:

1. the Report fully complies with the requirements of Section 13(a) or 15(d) of the Exchange Act; and

2. the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of Marsh & McLennan Companies, Inc.

Date:	October 27, 2017	/s/ Daniel S. Glaser
		Daniel S. Glaser
		President and Chief Executive Officer

Date:	October 27, 2017	/s/ Mark C. McGivney
		Mark C. McGivney
		Chief Financial Officer

XML

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 25, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	MARSH & MCLENNAN COMPANIES, INC.
Entity Central Index Key	0000062709
Trading Symbol	MMC
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		510,356,826

XML

Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 3,341	$ 3,135	$ 10,339	$ 9,847
Expense:
Compensation and benefits	1,906	1,817	5,786	5,543
Other operating expenses	838	746	2,383	2,273
Operating expenses	2,744	2,563	8,169	7,816
Operating income	597	572	2,170	2,031
Interest income	2	0	6	4
Interest expense	(60)	(47)	(178)	(141)
Investment income		1	3
Investment loss	(2)			(2)
Income before income taxes	537	525	2,001	1,892
Income tax expense	140	141	519	538
Net income before non-controlling interests	397	384	1,482	1,354
Less: Net income attributable to non-controlling interests	4	5	19	22
Net income attributable to the Company	$ 393	$ 379	$ 1,463	$ 1,332
Net Income Per Share Attributable to the Company:
Basic net income per share attributable to the Company (usd per share)	$ 0.77	$ 0.73	$ 2.85	$ 2.56
Diluted net income per share attributable to the Company (usd per share)	$ 0.76	$ 0.73	$ 2.81	$ 2.54
Average number of shares outstanding:
Average number of shares outstanding - Basic	512	518	514	520
Average number of shares outstanding - Diluted	519	523	520	525
Shares outstanding at September 30,	511	516	511	516

XML

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income before non-controlling interests	$ 397	$ 384	$ 1,482	$ 1,354
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	127	(52)	652	(373)
Unrealized investment (losses) gains	(8)	1	11	1
(Loss) gain related to pension/post-retirement plans	(168)	82	(140)	383
Other comprehensive (loss) income, before tax	(49)	31	523	11
Income tax (credit) expense on other comprehensive income	(30)	19	(10)	80
Other comprehensive (loss) income, net of tax	(19)	12	533	(69)
Comprehensive income	378	396	2,015	1,285
Less: comprehensive income attributable to non-controlling interest	4	5	19	22
Comprehensive income attributable to the Company	$ 374	$ 391	$ 1,996	$ 1,263

XML

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,078	$ 1,026
Receivables
Commissions and fees	3,651	3,370
Advanced premiums and claims	52	83
Other	311	286
Gross receivables	4,014	3,739
Less-allowance for doubtful accounts and cancellations	(105)	(96)
Net receivables	3,909	3,643
Other current assets	228	215
Total current assets	5,215	4,884
Goodwill	9,100	8,369
Other intangible assets	1,320	1,126
Fixed assets (net of accumulated depreciation and amortization of $1,822 at September 30, 2017 and $1,683 at December 31, 2016)	728	725
Pension related assets	1,155	776
Deferred tax assets	947	1,097
Other assets	1,225	1,213
Total assets	19,690	18,190
Current liabilities:
Short-term debt	13	312
Accounts payable and accrued liabilities	2,002	1,969
Accrued compensation and employee benefits	1,377	1,655
Accrued income taxes	229	146
Dividends payable	193	0
Total current liabilities	3,814	4,082
Fiduciary liabilities	5,128	4,241
Less – cash and investments held in a fiduciary capacity	(5,128)	(4,241)
Net fiduciary assets	0	0
Long-term debt	5,475	4,495
Pension, post-retirement and post-employment benefits	1,948	2,076
Liabilities for errors and omissions	316	308
Other liabilities	1,006	957
Commitments and contingencies	0	0
Equity:
Preferred stock, $1 par value, authorized 6,000,000 shares, none issued	0	0
Common stock, $1 par value, authorized 1,600,000,000 shares, issued 560,641,640 shares at September 30, 2017 and December 31, 2016	561	561
Additional paid-in capital	783	842
Retained earnings	13,113	12,388
Accumulated other comprehensive loss	(4,560)	(5,093)
Non-controlling interests	85	80
Stockholders' equity before treasury stock	9,982	8,778
Less – treasury shares, at cost, 49,484,693 shares at September 30, 2017 and 46,150,415 shares at December 31, 2016	(2,851)	(2,506)
Total equity	7,131	6,272
Total liabilities and stockholders' equity	$ 19,690	$ 18,190

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Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Fixed assets, accumulated depreciation and amortization	$ 1,822	$ 1,683
Preferred stock, par value (usd per share)	$ 1	$ 1
Preferred stock, shares authorized	6,000,000	6,000,000
Preferred stock, shares issued	0	0
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized	1,600,000,000	1,600,000,000
Common stock, shares issued	560,641,640	560,641,640
Treasury shares, shares	49,484,693	46,150,415

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Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating cash flows:
Net income before non-controlling interests	$ 1,482	$ 1,354
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization of fixed assets and capitalized software	234	231
Amortization of intangible assets	122	99
Adjustments and payments related to contingent consideration liability	(30)	(37)
Gain on deconsolidation of subsidiary	0	(12)
Provision for deferred income taxes	52	43
(Gain) loss on investments	(3)	2
Loss on disposition of assets	9	3
Share-based compensation expense	111	84
Changes in assets and liabilities:
Net receivables	(248)	(162)
Other current assets	(14)	(20)
Other assets	(18)	(2)
Accounts payable and accrued liabilities	11	(29)
Accrued compensation and employee benefits	(278)	(349)
Accrued income taxes	77	65
Contributions to pension and other benefit plans in excess of current year expense/credit	(337)	(214)
Other liabilities	83	(3)
Effect of exchange rate changes	(116)	59
Net cash provided by operations	1,137	1,112
Financing cash flows:
Purchase of treasury shares	(600)	(625)
Proceeds from debt	987	347
Repayments of debt	(313)	(9)
Shares withheld for taxes on vested units – treasury shares	(49)	(38)
Issuance of common stock from treasury shares	134	154
Payments of deferred and contingent consideration for acquisitions	(127)	(96)
Distributions of non-controlling interests	(14)	(12)
Dividends paid	(545)	(504)
Net cash used for financing activities	(527)	(783)
Investing cash flows:
Capital expenditures	(217)	(174)
Net sales (purchases) of long-term investments	(21)	(4)
Proceeds from sales of fixed assets	4	5
Acquisitions	(629)	(88)
Other, net	4	3
Net cash used for investing activities	(859)	(258)
Effect of exchange rate changes on cash and cash equivalents	301	(57)
Increase in cash and cash equivalents	52	14
Cash and cash equivalents at beginning of period	1,026	1,374
Cash and cash equivalents at end of period	$ 1,078	$ 1,388

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Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Shares	Non-Controlling Interests
Balance, beginning of year at Dec. 31, 2015		$ 561	$ 861	$ 11,302	$ (4,220)	$ (1,991)	$ 89
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in accrued stock compensation costs			14
Issuance of shares under stock compensation plans and employee stock purchase plans and related tax impact in 2016			(63)			250
Other			0
Net income	$ 1,354			1,332			22
Dividend equivalents declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)				(5)
Dividends declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)				(676)
Other comprehensive income (loss), net of tax	(69)				(69)
Purchase of treasury shares						(625)
Deconsolidation of subsidiary							(14)
Distributions and other changes							(14)
Balance, end of period at Sep. 30, 2016	6,754		812	11,953	(4,289)	(2,366)	83
Balance, beginning of year at Dec. 31, 2016	6,272	$ 561	842	12,388	(5,093)	(2,506)	80
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in accrued stock compensation costs			26
Issuance of shares under stock compensation plans and employee stock purchase plans and related tax impact in 2016			(82)			255
Other			(3)
Net income	1,482			1,463			19
Dividend equivalents declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)				(4)
Dividends declared – (per share amounts: $1.43 in 2017 and $1.30 in 2016)				(734)
Other comprehensive income (loss), net of tax	533				533
Purchase of treasury shares						(600)
Deconsolidation of subsidiary							0
Distributions and other changes							(14)
Balance, end of period at Sep. 30, 2017	$ 7,131		$ 783	$ 13,113	$ (4,560)	$ (2,851)	$ 85

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Consolidated Statements of Equity (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)	$ 1.43	$ 1.30
Dividend equivalents declared per share (in dollars per share)	$ 1.43	$ 1.30

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Nature of Operations

9 Months Ended

Sep. 30, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of Operations

Nature of Operations

Marsh & McLennan Companies, Inc. and its consolidated subsidiaries (the "Company"), a global professional services firm, is organized based on the different services that it offers. Under this structure, the Company’s two segments are Risk and Insurance Services and Consulting.

The Risk and Insurance Services segment provides risk management services and insurance broking, reinsurance broking and insurance program management services for businesses, public entities, insurance companies, associations, professional services organizations and private clients. The Company conducts business in this segment through Marsh and Guy Carpenter.

The Company conducts business in its Consulting segment through Mercer and Oliver Wyman Group. Mercer provides consulting expertise, advice, services and solutions in the areas of health, wealth and career. As of September 30, 2017, Mercer had assets under delegated management of approximately $210 billion worldwide. Oliver Wyman Group provides specialized management and economic and brand consulting services.

Acquisitions impacting the Risk and Insurance Services and Consulting segments are discussed in Note 7 to the consolidated financial statements.

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Principles of Consolidation and Other Matters

9 Months Ended

Sep. 30, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Principles of Consolidation and Other Matters

Principles of Consolidation and Other Matters

The consolidated financial statements included herein have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission. While certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been omitted pursuant to such rules and regulations for interim filings, the Company believes that the information and disclosures presented are adequate to make such information and disclosures not misleading. These consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 (the "2016 Form 10-K").

The financial information contained herein reflects all normal recurring adjustments which are, in the opinion of management, necessary for a fair presentation of the Company’s consolidated financial statements as of and for the three and nine month periods ended September 30, 2017 and 2016.

Cash and Cash Equivalents

Cash and cash equivalents primarily consist of certificates of deposit and time deposits, with original maturities of three months or less, and money market funds. The estimated fair value of the Company's cash and cash equivalents approximates their carrying value. The Company is required to maintain operating funds of approximately $184 million, primarily related to regulatory requirements outside the United States or as collateral under captive insurance arrangements.

Investments

The Company holds investments in certain private equity funds. Investments in private equity funds are accounted for under the equity method of accounting using a consistently applied three-month lag period adjusted for any known significant changes from the lag period to the reporting date of the Company. The underlying private equity funds follow investment company accounting, where investments within the fund are carried at fair value. Investment gains or losses for the Company's proportionate share of the change in fair value of the funds are recorded in earnings. Investments accounted for using the equity method of accounting are included in other assets in the consolidated balance sheets.

The caption "Investment income (loss)" in the consolidated statements of income comprises realized and unrealized gains and losses from investments recognized in earnings. It includes, when applicable, other than temporary declines in the value of debt and available-for-sale securities and equity method gains or losses on the Company's investments in private equity funds. The Company recorded a net investment loss of $2 million in the third quarter of 2017 compared to a net investment gain of less than $1 million for the same period in 2016, and net investment income of $3 million compared to a net investment loss of $2 million for the nine months ended September 30, 2017 and 2016, respectively.

Income Taxes

The Company's effective tax rate in the third quarter of 2017 was 26.2% compared with 26.8% in the third quarter of 2016. The effective tax rate for the first nine months of 2017 and 2016 was 25.9% and 28.4%, respectively. The rates reflect foreign operations which are taxed at rates below the U.S. statutory tax rate, including the effect of repatriation, as well as the impact of discrete tax matters such as tax legislation, changes in valuation allowances, nontaxable adjustments to contingent acquisition consideration and, starting in 2017, excess tax benefits related to share-based compensation.

The Company is routinely examined by tax authorities in the jurisdictions in which it has significant operations. The Company regularly considers the likelihood of assessments in each of the taxing jurisdictions resulting from examinations. When evaluating the potential imposition of penalties, the Company considers a number of relevant factors under penalty statutes, including appropriate disclosure of the tax return position, the existence of legal authority supporting the Company's position, and reliance on the opinion of professional tax advisors.

The Company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in tax returns. The Company's gross unrecognized tax benefits decreased from $65 million at December 31, 2016 to $64 million at September 30, 2017 due to settlements of audits and expirations of statutes of limitation, partially offset by current accruals. It is reasonably possible that the total amount of unrecognized tax benefits will decrease between zero and approximately $9 million within the next twelve months due to settlements of audits and expirations of statutes of limitation.

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Fiduciary Assets and Liabilities

9 Months Ended

Sep. 30, 2017

Fiduciary Assets And Liabilities [Abstract]

Fiduciary Assets and Liabilities

Fiduciary Assets and Liabilities

In its capacity as an insurance broker or agent, the Company collects premiums from insureds and, after deducting its commissions, remits the premiums to the respective insurance underwriters. The Company also collects claims or refunds from underwriters on behalf of insureds. Unremitted insurance premiums and claims proceeds are held by the Company in a fiduciary capacity. Risk and Insurance Services revenue includes interest on fiduciary funds of $11 million and $8 million for the three months ended September 30, 2017 and 2016, respectively, and $28 million and $20 million for the nine months ended September 30, 2017 and 2016, respectively. The Consulting segment recorded fiduciary interest income of $2 million and $1 million for each of the three month periods ended September 30, 2017 and 2016, respectively, and $3 million and $2 million for the nine months ended September 30, 2017 and 2016, respectively. Since fiduciary assets are not available for corporate use, they are shown in the consolidated balance sheets as an offset to fiduciary liabilities.

Net uncollected premiums and claims and the related payables amounted to $6.8 billion at September 30, 2017 and $7.0 billion atDecember 31, 2016. The Company is not a principal to the contracts under which the right to receive premiums or the right to receive reimbursement of insured losses arises. Accordingly, net uncollected premiums and claims and the related payables are not assets and liabilities of the Company and are not included in the accompanying consolidated balance sheets.

In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. These advances are made from corporate funds and are reflected in the accompanying consolidated balance sheets as receivables.

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Per Share Data

9 Months Ended

Sep. 30, 2017

Earnings Per Share [Abstract]

Per Share Data

Per Share Data

Basic net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock.

Diluted net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock, which have been adjusted for the dilutive effect of potentially issuable common shares.

Basic and Diluted EPS Calculation	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share amounts)	2017		2016		2017		2016
Net income before non-controlling interests	$	397	$	384	$	1,482	$	1,354
Less: Net income attributable to non-controlling interests	4		5		19		22
Net income attributable to the Company	$	393	$	379	$	1,463	$	1,332
Basic weighted average common shares outstanding	512		518		514		520
Dilutive effect of potentially issuable common shares	7		5		6		5
Diluted weighted average common shares outstanding	519		523		520		525
Average stock price used to calculate common stock equivalents	$	79.35	$	66.98	$	75.36	$	62.33

There were 11.3 million and 13.6 million stock options outstanding as of September 30, 2017 and 2016, respectively.

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Supplemental Disclosures to the Consolidated Statements of Cash Flows

9 Months Ended

Sep. 30, 2017

Supplemental Cash Flow Information [Abstract]

Supplemental Disclosures to the Consolidated Statements of Cash Flows

Supplemental Disclosures to the Consolidated Statements of Cash Flows

The following schedule provides additional information concerning acquisitions, interest and income taxes paid for the nine-month periods ended September 30, 2017 and 2016.

(In millions)	2017			2016
Assets acquired, excluding cash	$	852		$	121
Liabilities assumed	(129		)	(4		)
Contingent/deferred purchase consideration	(94		)	(29		)
Net cash outflow for current year acquisitions	$	629		$	88

(In millions)	2017		2016
Interest paid	$	174	$	148
Income taxes paid, net of refunds	$	406	$	417

The classification of contingent consideration in the statement of cash flows is determined by whether the payment was part of the initial liability established on the acquisition date (financing) or an adjustment to the acquisition date liability (operating).

The following amounts are included in the consolidated statements of cash flows as a financing activity. The Company paid deferred and contingent consideration of $127 million for the nine months ended September 30, 2017. This consisted of deferred purchase consideration related to prior years' acquisitions of $47 million and contingent consideration of $80 million. For the nine months ended September 30, 2016, the Company paid deferred and contingent consideration of $96 million, consisting of deferred purchase consideration related to prior years' acquisitions of $53 million and contingent consideration of $43 million.

The following amounts are included in the operating section of the consolidated statements of cash flows. For the nine months ended September 30, 2017, the Company recorded a net credit for adjustments to acquisition related accounts of $3 million and made contingent consideration payments of $27 million. For the nine months ended September 30, 2016, the Company recorded a net charge for adjustments related to acquisition related accounts of $5 million and made contingent consideration payments of $42 million.

The Company had non-cash issuances of common stock under its share-based payment plan of $88 million and $71 million for the nine months ended September 30, 2017 and 2016, respectively. The Company recorded stock-based compensation expense for equity awards related to restricted stock units, performance stock units and stock options of $111 million and $84 million for the nine-month periods ended September 30, 2017 and 2016, respectively.

Effective January 1, 2017, the Company adopted new accounting guidance related to share-based compensation, that requires companies to record excess tax benefits and tax deficiencies as an income tax benefit or expense in the income statement and classify excess tax benefits as an operating activity in the statement of cash flows. Prior to the adoption of this standard, the Company recorded excess tax benefits in equity in the consolidated balance sheet and as a financing activity in the consolidated statement of cash flows. For the nine months ended September 30, 2017, the adoption of this new standard reduced income tax expense in the consolidated statement of income by approximately $58 million. For the nine months ended September 30, 2016, the Company recorded an excess tax benefit of $30 million as an increase to equity in its consolidated balance sheet, which was reflected as cash provided by financing activities in the consolidated statement of cash flows.

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Other Comprehensive Income (Loss)

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Other Comprehensive Income (Loss)

Other Comprehensive Income (Loss)

The changes, net of tax, in the balances of each component of Accumulated Other Comprehensive Income ("AOCI") for the three and nine-month periods ended September 30, 2017 and 2016, including amounts reclassified out of AOCI, are as follows:

(In millions)	Unrealized Investment Gains (Losses)			Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2017	$	30		$	(3,215	)	$	(1,356	)	$	(4,541	)
Other comprehensive (loss) income before reclassifications	(5		)	(173		)	126			(52		)
Amounts reclassified from accumulated other comprehensive income	—			33			—			33
Net current period other comprehensive (loss) income	(5		)	(140		)	126			(19		)
Balance as of September 30, 2017	$	25		$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2016	$	6	$	(2,885	)	$	(1,422	)	$	(4,301	)
Other comprehensive income (loss) before reclassifications	1		36			(54		)	(17		)
Amounts reclassified from accumulated other comprehensive income	—		29			—			29
Net current period other comprehensive income (loss)	1		65			(54		)	12
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2017	$	19	$	(3,232	)	$	(1,880	)	$	(5,093	)
Other comprehensive income (loss) before reclassifications	6		(219		)	650			437
Amounts reclassified from accumulated other comprehensive income	—		96			—			96
Net current period other comprehensive income (loss)	6		(123		)	650			533
Balance as of September 30, 2017	$	25	$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2016	$	6	$	(3,124	)	$	(1,102	)	$	(4,220	)
Other comprehensive income (loss) before reclassifications	1		214			(374		)	(159		)
Amounts reclassified from accumulated other comprehensive income	—		90			—			90
Net current period other comprehensive income (loss)	1		304			(374		)	(69		)
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

The components of other comprehensive income (loss) for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

Three Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	127		$	1		$	126		$	(52	)	$	2	$	(54	)
Unrealized investment (losses) gains	(8		)	(3		)	(5		)	1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			1			1		—
Net actuarial losses (a)	43			10			33			41			12		29
Subtotal	43			10			33			42			13		29
Effect of remeasurement	3			—			3			—			—		—
Effect of settlement	1			—			1			—			—		—
Foreign currency translation (losses) gains	(215		)	(38		)	(177		)	40			4		36
Pension/post-retirement plans (losses) gains	(168		)	(28		)	(140		)	82			17		65
Other comprehensive (loss) income	$	(49	)	$	(30	)	$	(19	)	$	31		$	19	$	12
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Income tax credits on prior service cost and net actuarial losses are included in income tax expense.

Nine Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	652		$	2		$	650		$	(373	)	$	1	$	(374	)
Unrealized investment gains	11			5			6			1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			2			1		1
Net actuarial losses (a)	125			29			96			125			36		89
Subtotal	125			29			96			127			37		90
Effect of remeasurement	12			3			9			(1		)	—		(1		)
Effect of curtailment	(1		)	—			(1		)	3			1		2
Effect of settlement	2			—			2			1			—		1
Foreign currency translation (losses) gains	(277		)	(49		)	(228		)	253			41		212
Other	(1		)	—			(1		)	—			—		—
Pension/post-retirement plans (losses) gains	(140		)	(17		)	(123		)	383			79		304
Other comprehensive income (loss)	$	523		$	(10	)	$	533		$	11		$	80	$	(69	)
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Tax on prior service cost and net actuarial losses is included in income tax expense.

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Acquisitions

9 Months Ended

Sep. 30, 2017

Business Combinations [Abstract]

Acquisitions

Acquisitions

The Company has continued its strategy to grow its businesses and build shareholder value through strategic acquisitions. The Company’s acquisitions have been accounted for as business combinations. Net assets and results of operations are included in the Company’s consolidated financial statements commencing at the respective purchase closing dates. In connection with acquisitions, the Company records the estimated value of the net tangible assets purchased and the value of the identifiable intangible assets purchased, which typically consist of purchased customer lists, developed technology, trademarks and non-compete agreements. The valuation of purchased intangible assets involves significant estimates and assumptions. Until final valuations are complete, any change in assumptions could affect the carrying value of tangible assets, goodwill and identifiable intangible assets.

The Risk and Insurance Services segment completed seven acquisitions during the first nine months of 2017.

• January – Marsh & McLennan Agency ("MMA") acquired J. Smith Lanier & Co. ("JSL"), a privately held insurance brokerage firm providing insurance, risk management, and employee benefits solutions to businesses and individuals throughout the U.S.

• February – MMA acquired iaConsulting Services, a Texas-based employee benefits consulting firm.

• March – MMA acquired Blakestad, Inc., a Minnesota-based private client and commercial lines insurance agency, and RJF Financial Services, a Minnesota-based retirement advisory firm.

• May – MMA acquired Insurance Partners of Texas, a Texas-based employee benefits consulting firm.

• August – Marsh acquired International Catastrophe Insurance Managers, LLC, a Colorado-based property and casualty insurance agent, and MMA acquired Hendrick & Hendrick, Inc., a Texas-based insurance agency.

The Consulting segment completed one acquisition during the first nine months of 2017.

• August – Mercer acquired Jaeson Associates, a Portugal-based talent management consulting organization.

Total purchase consideration for acquisitions made during the nine months ended September 30, 2017 was $734 million, which consisted of cash paid of $640 million and deferred purchase and estimated contingent consideration of $94 million. Contingent consideration arrangements are based primarily on earnings before interest, tax, depreciation and amortization ("EBITDA") or revenue targets over a period of two to four years. The fair value of the contingent consideration was based on projected revenue or EBITDA of the acquired entities. Estimated fair values of assets acquired and liabilities assumed are subject to adjustment when purchase accounting is finalized. The Company also paid $47 million of deferred purchase consideration and $107 million of contingent consideration related to acquisitions made in prior years.

The following table presents the preliminary allocation of the acquisition cost to the assets acquired and liabilities assumed during 2017 based on their fair values:

For the Nine Months Ended September 30, 2017
(In millions)
Cash	$	640
Estimated fair value of deferred/contingent consideration	94
Total Consideration	$	734
Allocation of purchase price:
Cash and cash equivalents	$	11
Accounts receivable, net	17
Property, plant, and equipment	7
Other intangible assets	293
Goodwill	533
Other assets	2
Total assets acquired	863
Current liabilities	21
Other liabilities	108
Total liabilities assumed	129
Net assets acquired	$	734

The following chart provides information about other intangible assets acquired during 2017:

	Amount		Weighted Average Amortization Period
Client relationships	$	252	12 years
Other	41		5 years
	$	293

Prior-Year Acquisitions

The Risk and Insurance Services segment completed nine acquisitions during 2016.

• February – MMA acquired The Celedinas Agency, Inc., a Florida-based brokerage firm, providing property, casualty and marine insurance, as well as employee benefits services, and Aviation Solutions, LLC, a Missouri-based aviation risk advisor and insurance broker.

• March – MMA acquired Corporate Consulting Services, Ltd., a New York-based insurance brokerage and human resource consulting firm.

• August – MMA acquired Benefits Advisory Group LLC, an Atlanta-based employee benefits consulting firm.

• September – MMA acquired Vero Insurance, Inc., a Florida-based agency specializing in private client insurance services.

• November – MMA acquired Benefits Resource Group Agency, LLC, an Ohio-based benefits consulting firm and Presidio Benefits Group, Inc., a California-based employee benefits consulting firm.

• December – Marsh acquired AD Corretora, a multi-line broker located in Brazil, and Bluefin Insurance Group, Ltd, a U.K.-based insurance brokerage.

The Consulting segment completed six acquisitions during 2016.

• January – Mercer acquired The Positive Ageing Company Limited, a U.K.-based firm providing advice on issues surrounding the aging workforce.

• April – Mercer acquired the Extratextual software system and related client contracts. Extratextual is a web based compliance system that assists clients to manage and meet their compliance and risk management obligations.

• December – Oliver Wyman acquired LShift Limited, a software development company, and Mercer acquired Sirota Consulting LLC, a global provider of employee benefit solutions; Pillar Administration, a superannuation provider located in Australia; and Thomsons Online Benefits, a U.K.-based global benefits software business.

Total purchase consideration for acquisitions made during the first nine months of 2016 was $119 million, which consisted of cash paid of $90 million and deferred purchase and estimated contingent consideration of $29 million. Contingent consideration arrangements are primarily based on EBITDA or revenue targets over a period of two to four years. The fair value of the contingent consideration was based on projected revenue or earnings of the acquired entities. Estimated fair values of assets acquired and liabilities assumed are subject to adjustment when purchase accounting is finalized. In the first nine months of 2016, the Company also paid $53 million of deferred purchase consideration and $85 million of contingent consideration related to acquisitions made in prior years.

Pro-Forma Information

The following unaudited pro-forma financial data gives effect to the acquisitions made by the Company during 2017 and 2016. In accordance with accounting guidance related to pro-forma disclosures, the information presented for current year acquisitions is as if they occurred on January 1, 2016 and reflects acquisitions made in 2016 as if they occurred on January 1, 2015. The unaudited pro-forma information adjusts for the effects of amortization of acquired intangibles. The unaudited pro-forma financial data is presented for illustrative purposes only and is not necessarily indicative of the operating results that would have been achieved if such acquisitions had occurred on the dates indicated, nor is it necessarily indicative of future consolidated results.

	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share figures)	2017		2016		2017		2016
Revenue	$	3,349	$	3,256	$	10,416	$	10,232
Net income attributable to the Company	$	392	$	372	$	1,466	$	1,320
Basic net income per share attributable to the Company	$	0.77	$	0.72	$	2.85	$	2.54
Diluted net income per share attributable to the Company	$	0.76	$	0.71	$	2.82	$	2.52

The consolidated statements of income include the results of operations of acquired companies since their respective acquisition dates. The consolidated statements of income for the three and nine-month periods ended September 30, 2017 include approximately $40 million and$103 million of revenue, respectively, and an operating loss of $1 million and operating income of $16 million, respectively, related to acquisitions made in 2017.

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Goodwill and Other Intangibles

9 Months Ended

Sep. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangibles

Goodwill and Other Intangibles

The Company is required to assess goodwill and any indefinite-lived intangible assets for impairment annually, or more frequently if circumstances indicate impairment may have occurred. The Company performs the annual impairment assessment for each of its reporting units during the third quarter of each year. In accordance with applicable accounting guidance, the Company assesses qualitative factors to determine whether it is necessary to perform the two-step goodwill impairment test. The Company considers numerous factors, which include whether the fair value of each reporting unit exceeded its carrying value by a substantial margin in its most recent estimate of reporting unit fair values, whether significant acquisitions or dispositions occurred which might alter the fair value of its reporting units, macroeconomic conditions and their potential impact on reporting unit fair values, actual performance compared with budget and prior projections used in its estimation of reporting unit fair values, industry and market conditions, and the year-over-year change in the Company’s share price. The Company completed its qualitative assessment in the third quarter of 2017 and concluded that a two-step goodwill impairment test was not required in 2017 and that goodwill was not impaired.

Changes in the carrying amount of goodwill are as follows:

September 30,
(In millions)	2017		2016
Balance as of January 1, as reported	$	8,369	$	7,889
Goodwill acquired	533		74
Other adjustments(a)	198		12
Balance at September 30,	$	9,100	$	7,975

^(a)  The increase in 2017 primarily reflects the impact of foreign exchange.

Goodwill allocable to the Company’s reportable segments at September 30, 2017 is as follows: Risk and Insurance Services, $6.5 billion and Consulting, $2.6 billion.

Other intangible assets that are not deemed to have an indefinite life are amortized over their estimated lives and reviewed for impairment upon the occurrence of certain triggering events in accordance with applicable accounting literature.

The gross cost and accumulated amortization at September 30, 2017 and December 31, 2016 are as follows:

	September 30, 2017						December 31, 2016
(In millions)	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Client Relationships	$	1,679	$	487	$	1,192	$	1,390	$	392	$	998
Other (a)	231		103		128		204		76		128
Amortized intangibles	$	1,910	$	590	$	1,320	$	1,594	$	468	$	1,126

^(a) Primarily non-compete agreements, trade names and developed technology.

Aggregate amortization expense for the nine months ended September 30, 2017 and2016 was $122 million and $99 million, respectively. The estimated future aggregate amortization expense is as follows:

For the Years Ending December 31,
(In millions)	Estimated Expense
2017 (excludes amortization through September 30, 2017)	$	50
2018	176
2019	166
2020	145
2021	135
Subsequent years	648
	$	1,320

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Fair Value Measurements

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

Fair Value Hierarchy

The Company has categorized its assets and liabilities that are valued at fair value on a recurring basis into a three-level fair value hierarchy as defined by the Financial Accounting Standards Board ("FASB"). The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets and liabilities (Level 1) and lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy, for disclosure purposes, is determined based on the lowest level input that is significant to the fair value measurement. Assets and liabilities recorded in the consolidated balance sheets at fair value are categorized based on the inputs in the valuation techniques as follows:

Level 1. Assets and liabilities whose values are based on unadjusted quoted prices for identical assets or liabilities in an active market (examples include active exchange-traded equity securities and exchange-traded money market mutual funds).

Assets and liabilities measured using Level 1 inputs include exchange-traded equity securities, exchange-traded mutual funds and money market funds.

Level 2. Assets and liabilities whose values are based on the following:

a) Quoted prices for similar assets or liabilities in active markets;

b) Quoted prices for identical or similar assets or liabilities in non-active markets (examples include corporate and municipal bonds, which trade infrequently);

c) Pricing models whose inputs are observable for substantially the full term of the asset or liability (examples include most over-the-counter derivatives, including interest rate and currency swaps); and

d) Pricing models whose inputs are derived principally from or corroborated by observable market data through correlation or other means for substantially the full asset or liability (for example, certain mortgage loans).

The Company does not have any assets or liabilities that are measured using Level 2 inputs.

Level 3. Assets and liabilities whose values are based on prices, or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs reflect management’s own assumptions about the assumptions a market participant would use in pricing the asset or liability.

Liabilities measured using Level 3 inputs include liabilities for contingent purchase consideration.

Valuation Techniques

Equity Securities, Money Market Funds and Mutual Funds – Level 1

Investments for which market quotations are readily available are valued at the sale price on their principal exchange or, for certain markets, official closing bid price. Money market funds are valued using a valuation technique that results in price per share at $1.00.

Contingent Purchase Consideration Liability – Level 3

Purchase consideration for some acquisitions made by the Company includes contingent consideration arrangements. These arrangements typically provide for the payment of additional consideration if earnings or revenue targets are met over periods from two to four years. The fair value of the contingent purchase consideration liability is estimated as the present value of future cash flows to be paid, based on projections of revenue and earnings and related targets of the acquired entities.

The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016.

	Identical Assets (Level 1)				Observable Inputs (Level 2)				Unobservable Inputs (Level 3)				Total
(In millions)	09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16
Assets:
Financial instruments owned:
Exchange traded equity securities(a)	$	99	$	89	$	—	$	—	$	—	$	—	$	99	$	89
Mutual funds(a)	143		141		—		—		—		—		143		141
Money market funds(b)	54		22		—		—		—		—		54		22
Total assets measured at fair value	$	296	$	252	$	—	$	—	$	—	$	—	$	296	$	252
Fiduciary Assets:
Money market funds	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Total fiduciary assets measured at fair value	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Liabilities:
Contingent purchase consideration liability(c)	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241
Total liabilities measured at fair value	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241

^(a)  Included in other assets in the consolidated balance sheets.

^(b)  Included in cash and cash equivalents in the consolidated balance sheets.

^(c)  Included in accounts payable and accrued liabilities and other liabilities in the consolidated balance sheets.

During the nine-month period ended September 30, 2017, there were no assets or liabilities that were transferred between any of the levels.

The table below sets forth a summary of the changes in fair value of the Company’s Level 3 liabilities as of September 30, 2017 and 2016 that represent contingent consideration related to acquisitions:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Balance at beginning of period,	$	203		$	279		$	241		$	309
Additions	2			1			36			9
Payments	(42		)	(35		)	(107		)	(85		)
Revaluation Impact	5			(13		)	(3		)	5
Other (a)	2			—			3			(6		)
Balance at September 30,	$	170		$	232		$	170		$	232

^(a) Primarily reflects the impact of foreign exchange.

The fair value of the contingent purchase consideration liability is based on projections of revenue and EBITDA for the acquired entities in relation to the established targets and is reassessed on a quarterly basis. As set forth in the table above, based on the Company's ongoing assessment of the fair value of contingent consideration, the Company recorded a net decrease in the estimated fair value of such liabilities for prior-period acquisitions of $3 million in the nine-month period ended September 30, 2017. A 5% increase in the above mentioned projections would increase the liability by approximately $18 million. A 5% decrease in the above mentioned projections would decrease the liability by approximately $19 million.

Long-Term Investments

The Company holds investments in certain private equity investments, public companies and private companies that are accounted for using the equity method of accounting. The carrying value of these investments was $405 million and $389 million at September 30, 2017 and December 31, 2016, respectively.

Private Equity Investments

The Company's investments in private equity funds were $72 million and $79 million at September 30, 2017 and December 31, 2016, respectively. The carrying values of these private equity investments approximate fair value. The underlying private equity funds follow investment company accounting, where investments within the fund are carried at fair value. The Company records in earnings, investment gains/losses for its proportionate share of the change in fair value of the funds. These investments are included in other assets in the consolidated balance sheets.

Investments in Public and Private Companies

Alexander Forbes: The Company owns approximately 33% of the common stock of Alexander Forbes, a South African company listed on the Johannesburg Stock Exchange, which it purchased in 2014 for 7.50 South African Rand per share. As of September 30, 2017, the carrying value of the Company’s investment in Alexander Forbes was approximately $268 million. As of September 30, 2017, the market value of the approximately 443 million shares of Alexander Forbes owned by the Company, based on the September 30, 2017 closing share price of 6.75 South African Rand per share, was approximately $225 million. The Company considered several factors in assessing its investment in Alexander Forbes, including its financial position, the near- and long-term prospects of Alexander Forbes and the broader South African economy and capital markets, the length of time and extent to which the market value was below cost and the Company’s intent and ability to retain the investment for a sufficient period of time to allow for anticipated recovery in market value. During the first nine months of 2017, the daily closing share price ranged from a high of 7.89 Rand (in early January) to a low of 5.99 Rand (in late April). During the third quarter of 2017, the Alexander Forbes average opening and closing stock price was approximately 6.75 Rand (approximately 90% of the original purchase price) and ranged from 6.40 Rand to 7.28 Rand (approximately 85% to 97% of the purchase price). Based on its assessment of the factors discussed above, the Company determined the investment was not impaired.

The Company’s investment in Alexander Forbes and its other equity investments in private insurance and consulting companies are accounted for using the equity method of accounting, the results of which are included in revenue in the consolidated statements of income and the carrying value of which is included in other assets in the consolidated balance sheets. The Company records its share of income or loss on its equity method investments on a one quarter lag basis.

Benefitfocus: On February 24, 2015, the Company purchased shares of common stock of Benefitfocus (NASDAQ:BNFT) constituting 9.9% of BNFT's outstanding capital stock as of the acquisition date. The purchase price for the BNFT shares and certain other rights and other consideration was approximately $75 million. Until December 31, 2016, the Company accounted for this investment under the cost method of accounting as the shares purchased were categorized as restricted. Effective December 31, 2016, these shares were no longer considered restricted for the purpose of determining if they are marketable securities under applicable accounting guidance, and are now accounted for as available for sale securities and included in other assets in the consolidated balance sheets. The value of the BNFT shares based on the closing price on the NASDAQ as of September 30, 2017 was approximately $95 million. During the first nine months of 2017 an unrealized gain related to these shares of approximately $11 million was recorded in other comprehensive income.

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Retirement Benefits

9 Months Ended

Sep. 30, 2017

Defined Benefit Plan [Abstract]

Retirement Benefits

Retirement Benefits

The Company maintains qualified and non-qualified defined benefit pension plans for some of its U.S. and non-U.S. eligible employees. The Company’s policy for funding its tax-qualified defined benefit pension plans is to contribute amounts at least sufficient to meet the funding requirements set forth by U.S. law and the laws of the non-U.S. jurisdictions in which the Company offers such plans.

The target asset allocation for the Company's U.S. Plan was 64% equities and equity alternatives and 36% fixed income and at September 30, 2017, the actual allocation for the Company's U.S. Plan was 65% equities and equity alternatives and 35% fixed income. The target allocation for the U.K. plans at September 30, 2017 was46% equities and equity alternatives and 54% fixed income. At September 30, 2017, the actual allocation for the U.K. Plans was 47% equities and equity alternatives and 53% fixed income. The Company's U.K. Plans comprised approximately 81% of non-U.S. plan assets at December 31, 2016. The assets of the Company's defined benefit plans are diversified and are managed in accordance with applicable laws and with the goal of maximizing the plans' real return within acceptable risk parameters. The Company generally uses threshold-based portfolio re-balancing to ensure the actual portfolio remains consistent with target asset allocation ranges.

The components of the net periodic benefit cost for defined benefit and other post-retirement plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	43		$	—	$	1
Interest cost	125			132			1		—
Expected return on plan assets	(232		)	(232		)	—		—
Amortization of prior service cost	—			1			1		1
Recognized actuarial loss	42			43			—		—
Net periodic benefit (credit) cost	$	(46	)	$	(13	)	$	2	$	2
Settlement loss	1			—			—		—
Total (credit) cost	$	(45	)	$	(13	)	$	2	$	2
Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	56		$	133		$	—	$	1
Interest cost	371			407			3		3
Expected return on plan assets	(686		)	(715		)	—		—
Amortization of prior service (credit) cost	(1		)	—			2		3
Recognized actuarial loss (gain)	125			127			—		(1		)
Net periodic benefit (credit) cost	$	(135	)	$	(48	)	$	5	$	6
Curtailment gain	(1		)	(5		)	—		—
Settlement loss	2			1			—		—
Total (credit) cost	$	(134	)	$	(52	)	$	5	$	6
U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	—		$	26		$	—	$	—
Interest cost	66			66			—		—
Expected return on plan assets	(89		)	(95		)	—		—
Amortization of prior service cost	—			—			1		1
Recognized actuarial loss	9			19			—		—
Net periodic benefit (credit) cost	$	(14	)	$	16		$	1	$	1

U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	—		$	79		$	—		$	—
Interest cost	198			198			1			1
Expected return on plan assets	(268		)	(285		)	—			—
Amortization of prior service cost	—			—			3			3
Recognized actuarial loss (gain)	28			55			(1		)	(1		)
Net periodic benefit (credit) cost	$	(42	)	$	47		$	3		$	3

In October 2016, the Company modified its U.S. defined benefit pension plans to discontinue further benefit accruals for participants after December 31, 2016. At the same time, the Company amended its U.S. defined contribution retirement plans for most of its U.S. employees to add an automatic Company contribution equal to 4% of eligible base pay beginning on January 1, 2017. This new Company contribution, together with the Company’s current matching contribution, provides eligible U.S. employees with the opportunity to receive a total contribution of up to 7% of eligible base pay. In addition, the U.S. qualified defined benefit plans were merged effective December 30, 2016.

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	17		$	—	$	1
Interest cost	59			66			1		—
Expected return on plan assets	(143		)	(137		)	—		—
Amortization of prior service cost	—			1			—		—
Recognized actuarial loss	33			24			—		—
Net periodic benefit (credit) cost	$	(32	)	$	(29	)	$	1	$	1
Settlement loss	1			—			—		—
Total (credit) cost	$	(31	)	$	(29	)	$	1	$	1

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	56		$	54		$	—		$	1
Interest cost	173			209			2			2
Expected return on plan assets	(418		)	(430		)	—			—
Amortization of prior service credit	(1		)	—			(1		)	—
Recognized actuarial loss	97			72			1			—
Net periodic benefit (credit) cost	$	(93	)	$	(95	)	$	2		$	3
Curtailment gain	(1		)	(5		)	—			—
Settlement loss	2			1			—			—
Total (credit) cost	$	(92	)	$	(99	)	$	2		$	3

In March 2017, the Company modified its defined benefit pension plans in Canada to discontinue further benefit accruals for participants after December 31, 2017 and replaced them with a defined contribution arrangement. The Company also amended its post-retirement benefits plan in Canada so that individuals who retire after April 1, 2019 will not be eligible to participate, except in certain situations. The Company re-measured the assets and liabilities of the plans, based on assumptions and market conditions on the amendment date.

The weighted average actuarial assumptions utilized to calculate the net periodic benefit costs for the U.S. and significant non-U.S. defined benefit plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits				Post-retirement Benefits
September 30,	2017		2016		2017		2016
Weighted average assumptions:
Expected return on plan assets	6.64	%	7.07	%	—		—
Discount rate	3.40	%	4.11	%	3.64	%	4.12	%
Rate of compensation increase*	1.77	%	2.44	%	—		—

*The 2017 assumption does not include a rate of compensation increase for the U.S. defined benefit plans since future benefit accruals were discontinued for those plans after December 31, 2016.

The Company made approximately $193 million of contributions to its U.S. and non-U.S. defined benefit plans in the first nine months of 2017. The Company expects to contribute approximately $63 million to its U.S. pension and non-U.S. pension plans during the remainder of 2017.

Defined Contribution Plans

The Company maintains certain defined contribution plans for its employees, the most significant being in the U.S. and the U.K. The cost of these U.S. and U.K. defined contribution plans was $99 million and $56 million, respectively, for the nine months ended September 30,2017.

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Debt

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Debt

Debt

The Company’s outstanding debt is as follows:

(In millions)	September 30, 2017		December 31, 2016
Short-term:
Commercial paper	$	—	$	50
Current portion of long-term debt	13		262
	13		312
Long-term:
Senior notes – 2.30% due 2017	—		250
Senior notes – 2.55% due 2018	250		249
Senior notes – 2.35% due 2019	299		299
Senior notes – 2.35% due 2020	498		497
Senior notes – 4.80% due 2021	498		498
Senior notes – 2.75% due 2022	496		—
Senior notes – 3.30% due 2023	347		347
Senior notes – 4.05% due 2023	248		248
Senior notes – 3.50% due 2024	596		596
Senior notes – 3.50% due 2025	496		495
Senior notes – 3.75% due 2026	596		596
Senior notes – 5.875% due 2033	297		297
Senior notes – 4.35% due 2047	492		—
Mortgage – 5.70% due 2035	373		382
Other	2		3
	5,488		4,757
Less current portion	13		262
	$	5,475	$	4,495

The senior notes in the table above are registered by the Company with the Securities and Exchange Commission and are not guaranteed.

The Company has established a short-term debt financing program of up to $1.5 billion through the issuance of commercial paper. The proceeds from the issuance of commercial paper are used for general corporate purposes. The Company had no commercial paper outstanding at September 30, 2017.

In January 2017, the Company issued $500 million of 2.75% senior notes due 2022 and $500 million of 4.35% senior notes due 2047. The Company used the net proceeds for general corporate purposes, including the repayment of a $250 million debt maturity in April 2017.

In March 2016, the Company issued $350 million of 3.30%seven-year senior notes. The Company used the net proceeds for general corporate purposes.

The Company and certain of its foreign subsidiaries maintain a $1.5 billion multi-currency five-year unsecured revolving credit facility. The interest rate on this facility is based on LIBOR plus a fixed margin which varies with the Company's credit ratings. This facility expires in November 2020 and requires the Company to maintain certain coverage and leverage ratios which are tested quarterly. There were no borrowings outstanding under this facility at September 30, 2017.

Fair Value of Short-term and Long-term Debt

The estimated fair value of the Company’s short-term and long-term debt is provided below. Certain estimates and judgments were required to develop the fair value amounts. The fair value amounts shown below are not necessarily indicative of the amounts that the Company would realize upon disposition, nor do they indicate the Company’s intent or need to dispose of the financial instrument.

	September 30, 2017				December 31, 2016
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Short-term debt	$	13	$	13	$	312	$	313
Long-term debt	$	5,475	$	5,720	$	4,495	$	4,625

The fair value of the Company’s short-term debt consists primarily of term debt maturing within the next year and its fair value approximates its carrying value. The estimated fair value of a primary portion of the Company's long-term debt is based on discounted future cash flows using current interest rates available for debt with similar terms and remaining maturities. Short- and long-term debt would be classified as Level 2 in the fair value hierarchy.

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Restructuring Costs

9 Months Ended

Sep. 30, 2017

Restructuring and Related Activities [Abstract]

Restructuring Costs

Restructuring Costs

The Company recorded total restructuring costs of $32 million in the first nine months of 2017, primarily for severance at Mercer, Marsh and Corporate, as well as future rent under non-cancelable leases at Corporate. These costs were incurred in Risk and Insurance Services ($7 million), Consulting ($18 million) and Corporate ($7 million).

Details of the restructuring activity from January 1, 2016 through September 30, 2017, which includes liabilities from actions prior to 2017, are as follows:

(In millions)	Liability at 1/1/16		Amounts Accrued		Cash Paid			Other			Liability at 12/31/16		Amounts Accrued		Cash Paid			Other		Liability at 9/30/17
Severance	$	15	$	40	$	(22	)	$	(1	)	$	32	$	24	$	(42	)	$	—	$	14
Future rent under non-cancelable leases and other costs	78		4		(17		)	(4		)	61		8		(15		)	1		55
Total	$	93	$	44	$	(39	)	$	(5	)	$	93	$	32	$	(57	)	$	1	$	69

The expenses associated with the above initiatives are included in compensation and benefits and other operating expenses in the consolidated statements of income. The liabilities associated with these initiatives are classified on the consolidated balance sheets as accounts payable and accrued liabilities, other liabilities or accrued compensation and employee benefits, depending on the nature of the items.

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Common Stock

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Common Stock

Common Stock

During the first nine months of 2017, the Company repurchased approximately 8.0 million shares of its common stock for consideration of $600 million. During the first nine months of 2016, the Company repurchased approximately 10.0 million shares of its common stock for consideration of $625 million. In November 2016, the Board of Directors of the Company authorized the Company to repurchase up to $2.5 billion in shares of the Company's common stock, which superseded any prior authorizations. As of September 30, 2017, the Company remained authorized to repurchase up to approximately $1.8 billion in shares of its common stock. There is no time limit on the authorization.

The Company issued approximately 4.6 million and 4.5 million shares related to stock compensation and employee stock purchase plans during the first nine months of 2017 and 2016, respectively.

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Claims, Lawsuits And Other Contingencies

9 Months Ended

Sep. 30, 2017

Commitments and Contingencies Disclosure [Abstract]

Claims, Lawsuits, and Other Contingencies

Claims, Lawsuits and Other Contingencies

Litigation Matters

The Company and its subsidiaries are subject to a significant number of claims, lawsuits and proceedings in the ordinary course of business. Such claims and lawsuits consist principally of alleged errors and omissions in connection with the performance of professional services, including the placement of insurance, the provision of actuarial services for corporate and public sector clients, the provision of investment advice and investment management services to pension plans, the provision of advice relating to pension buy-out transactions and the provision of consulting services relating to the drafting and interpretation of trust deeds and other documentation governing pension plans. These claims may seek damages, including punitive and treble damages, in amounts that could be significant. In establishing liabilities for errors and omissions claims in accordance with FASB guidance on Contingencies - Loss Contingencies, the Company uses case level reviews by inside and outside counsel, and internal actuarial analysis by Oliver Wyman Group, a subsidiary of the Company, and other methods to estimate potential losses. A liability is established when a loss is both probable and reasonably estimable. The liability is reviewed quarterly and adjusted as developments warrant. In many cases, the Company has not recorded a liability, other than for legal fees to defend the claim, because we are unable, at the present time, to make a determination that a loss is both probable and reasonably estimable.

To the extent that expected losses exceed our deductible in any policy year, the Company also records an asset for the amount that we expect to recover under any available third-party insurance programs. The Company has varying levels of third-party insurance coverage, with policy limits and coverage terms varying significantly by policy year.

Governmental Inquiries and Enforcement Matters

Our activities are regulated under the laws of the United States and its various states, the European Union and its member states, and the other jurisdictions in which the Company operates.

Risk and Insurance Services Segment

In April 2017, the Financial Conduct Authority in the United Kingdom (the "FCA") commenced a civil competition investigation into the aviation insurance and reinsurance sector. In connection with that investigation, the FCA carried out an on-site inspection at the London office of Marsh Limited, our Marsh and Guy Carpenter operating subsidiary in the United Kingdom. The FCA indicated that it had reasonable grounds for suspecting that Marsh Limited and other participants in the market have been sharing competitively sensitive information within the aviation insurance and reinsurance broking sector.

In October 2017, the Company received a notice that the Directorate-General for Competition of the European Commission had commenced a civil investigation of a number of insurance brokers, including Marsh, regarding "the exchange of commercially sensitive information between competitors in relation to aviation and aerospace insurance and reinsurance broking products and services in the European Economic Area ("EEA"), as well as possible coordination between competitors." In light of the action taken by the European Commission, the FCA informed Marsh Limited at the same time that it has discontinued its investigation under U.K. competition law into the aviation insurance and reinsurance sector.

In July 2017, the Directorate-General for Competition of the European Commission together with the Irish Competition and Consumer Protection Commission conducted on-site inspections at the offices of Marsh and other industry participants in Dublin in connection with an investigation regarding the "possible participation in anticompetitive agreements and/or concerted practices contrary to [E.U. competition law] in the market for commercial motor insurance in the Republic of Ireland."

We are cooperating with these investigations and are conducting our own reviews. As these investigations are at early stages, we are unable to predict their likely timing, outcome or ultimate impact. There can be no assurance that the ultimate resolution of these or any related matters will not have a material adverse effect on our consolidated results of operations, financial condition or cash flows.

Consulting Segment

In June 2017, the FCA issued a final report in connection with a market study of the U.K. asset management industry, which includes asset managers and investment consultants, including Mercer. Following the report, in September 2017, the FCA announced its decision to refer the investment consulting and fiduciary management markets to the U.K. Competition & Markets Authority (the "CMA") for a market investigation. The CMA expects to conclude its investigation of the investment consulting and fiduciary management markets by March 2019.

In the ordinary course of business, the Company is also subject to other investigations, subpoenas, lawsuits and other regulatory actions undertaken by governmental authorities.

Other Contingencies-Guarantees

In connection with its acquisition of U.K.-based Sedgwick Group in 1998, the Company acquired several insurance underwriting businesses that were already in run-off, including River Thames Insurance Company Limited ("River Thames"), which the Company sold in 2001. Sedgwick guaranteed payment of claims on certain policies underwritten through the Institute of London Underwriters (the "ILU") by River Thames. The policies covered by this guarantee were reinsured up to £40 million by a related party of River Thames. Payment of claims under the reinsurance agreement is collateralized by segregated assets held in a trust. As of September 30, 2017, the reinsurance coverage exceeded the best estimate of the projected liability of the policies covered by the guarantee. To the extent River Thames or the reinsurer is unable to meet its obligations under those policies, a claimant may seek to recover from the Company under the guarantee.

From 1980 to 1983, the Company owned indirectly the English & American Insurance Company ("E&A"), which was a member of the ILU. The ILU required the Company to guarantee a portion of E&A's obligations. After E&A became insolvent in 1993, the ILU agreed to discharge the guarantee in exchange for the Company's agreement to post an evergreen letter of credit that is available to pay claims by policyholders on certain E&A policies issued through the ILU and incepting between July 3, 1980 and October 6, 1983. Certain claims have been paid under the letter of credit and the Company anticipates that additional claimants may seek to recover against the letter of credit.

* * * *

The pending proceedings described above and other matters not explicitly described in this Note 14 on Claims, Lawsuits and Other Contingencies may expose the Company or its subsidiaries to liability for significant monetary damages, fines, penalties or other forms of relief. Where a loss is both probable and reasonably estimable, the Company establishes liabilities in accordance with FASB guidance on Contingencies - Loss Contingencies. Except as described above, the Company is not able at this time to provide a reasonable estimate of the range of possible loss attributable to these matters or the impact they may have on the Company's consolidated results of operations, financial position or cash flows. This is primarily because these matters are still developing and involve complex issues subject to inherent uncertainty. Adverse determinations in one or more of these matters could have a material impact on the Company's consolidated results of operations, financial condition or cash flows in a future period.

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Segment Information

9 Months Ended

Sep. 30, 2017

Segment Reporting [Abstract]

Segment Information

Segment Information

The Company is organized based on the types of services provided. Under this structure, the Company’s segments are:

▪ Risk and Insurance Services, comprising insurance services (Marsh) and reinsurance services (Guy Carpenter); and

▪ Consulting, comprising Mercer and Oliver Wyman Group.

The accounting policies of the segments are the same as those used for the consolidated financial statements described in Note 1 to the Company’s 2016 Form 10-K. Segment performance is evaluated based on segment operating income, which includes directly related expenses, and charges or credits related to integration and restructuring but not the Company’s corporate-level expenses. Revenues are attributed to geographic areas on the basis of where the services are performed.

Selected information about the Company’s operating segments for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,							Nine Months Ended September 30,
(In millions)	Revenue				Operating Income (Loss)			Revenue				Operating Income (Loss)
2017–
Risk and Insurance Services	$	1,763		(a)	$	314		$	5,668		(c)	$	1,455
Consulting	1,587			(b)	329			4,705			(d)	853
Total Operating Segments	3,350				643			10,373				2,308
Corporate / Eliminations	(9		)		(46		)	(34		)		(138		)
Total Consolidated	$	3,341			$	597		$	10,339			$	2,170
2016–
Risk and Insurance Services	$	1,632		(a)	$	315		$	5,350		(c)	$	1,340
Consulting	1,513			(b)	308			4,530			(d)	838
Total Operating Segments	3,145				623			9,880				2,178
Corporate / Eliminations	(10		)		(51		)	(33		)		(147		)
Total Consolidated	$	3,135			$	572		$	9,847			$	2,031

^(a)  Includes inter-segment revenue of $1 million in both 2017and2016, interest income on fiduciary funds of $11 million and $8 million in 2017 and 2016, respectively, and equity method income of $2 million and $4 million in 2017 and 2016, respectively.

^(b)  Includes inter-segment revenue of $8 million and $9 million in 2017 and 2016, respectively, interest income on fiduciary funds of $2 million in 2017 and $1 million in 2016, respectively, and equity method income of $3 million in 2017 and $5 million in 2016, respectively.

^(c)  Includes inter-segment revenue of $5 million in both 2017 and2016, interest income on fiduciary funds of $28 million and $20 million in 2017 and 2016, respectively, and equity method income of $11 million in both 2017 and 2016.

^(d)  Includes inter-segment revenue of $29 million and $28 million in 2017 and 2016, respectively, interest income on fiduciary funds of $3 million in 2017 and $2 million in 2016, respectively, and equity method income of $12 million in 2017 and $14 million in 2016, respectively.

Details of operating segment revenue for the three and nine-month period ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Risk and Insurance Services
Marsh	$	1,490		$	1,370		$	4,713		$	4,427
Guy Carpenter	273			262			955			923
Total Risk and Insurance Services	1,763			1,632			5,668			5,350
Consulting
Mercer	1,149			1,109			3,335			3,227
Oliver Wyman Group	438			404			1,370			1,303
Total Consulting	1,587			1,513			4,705			4,530
Total Operating Segments	3,350			3,145			10,373			9,880
Corporate / Eliminations	(9		)	(10		)	(34		)	(33		)
Total	$	3,341		$	3,135		$	10,339		$	9,847

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New Accounting Guidance

9 Months Ended

Sep. 30, 2017

New Accounting Pronouncements and Changes in Accounting Principles [Abstract]

New Accounting Guidance

New Accounting Guidance

In March 2017, the FASB issued new guidance that changes the presentation of net periodic pension cost and net periodic postretirement cost (''net periodic benefit costs"). The new guidance requires employers to report the service cost component of net periodic benefit costs in the same line item as other compensation costs in the income statement. The other components of net periodic benefit costs are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. In addition, only the service cost component is eligible for capitalization, when applicable. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted as of the beginning of an annual period for which financial statements (interim or annual) have not been issued or made available for issuance. The new guidance requires retrospective application for the presentation of the service cost component and the other components of net periodic benefit costs, and prospective application for the capitalization of the service cost component. The adoption of this guidance will impact the presentation of the Company's results of operations, in particular, reducing net operating income, but will have no impact on the Company's net income.

In January 2017, the FASB issued new guidance to simplify the test for goodwill impairment. The new guidance eliminates the second step in the current two-step goodwill impairment process, under which a goodwill impairment loss is measured by comparing the implied fair value of a reporting unit's goodwill with the carrying amount of that goodwill for that reporting unit. The new guidance requires a one-step impairment test, in which the goodwill impairment charge is based on 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. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The guidance should be applied on a prospective basis with the nature of and reason for the change in accounting principle disclosed upon transition. The guidance is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In January 2017, the FASB issued guidance which clarifies the definition of a business in order to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted under certain circumstances and the guidance must be applied prospectively as of the beginning of the period of adoption. The Company is currently evaluating the impact, if any, the adoption of this standard will have on its financial position or results of operations.

In November 2016, the FASB issued new guidance which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. As a result, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented. Early adoption is permitted. The adoption of this guidance is not expected to have an impact on the Company's consolidated balance sheets or consolidated statements of cash flows.

In October 2016, the FASB also issued new guidance which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance eliminates the exception for an intra-entity transfer of an asset other than inventory. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The new guidance must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In August 2016, the FASB issued new guidance which adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows, including cash payments for debt prepayments or debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investees. The guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented unless retrospective application is impracticable. Early adoption is permitted. The Company does not expect the adoption of this standard to have a significant impact on its statement of cash flows.

In February 2016, the FASB issued new guidance intended to improve financial reporting for leases. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a financing or operating lease. However, unlike current GAAP, which requires that only capital leases be recognized on the balance sheet, the new guidance requires that both types of leases be recognized on the balance sheet. The new guidance will require additional disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, and additional information about the amounts recorded in the financial statements. The accounting by organizations that own the assets ("lessor") leased by the lessee will remain largely unchanged from current GAAP. However, the guidance contains some targeted improvements that are intended to align, where necessary, lessor accounting with the lessee accounting model and with the updated revenue recognition guidance issued in 2014. The new guidance on leases will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early application will be permitted. The Company is currently evaluating the impact the adoption of the guidance will have on its financial position and results of operations, but expects material "right to use" assets and lease liabilities to be recorded on its consolidated balance sheets.

In January 2016, the FASB issued new guidance intended to improve the recognition and measurement of financial instruments. The new guidance requires equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requires a reporting organization to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (also referred to as "own credit") when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company holds certain equity investments that are currently treated as available for sale securities, whereby the mark to market change is recorded to other comprehensive income in its consolidated balance sheet. The adoption of this new standard will impact the Company's results of operations, since the mark to market change to certain of its equity investments will be recorded in the consolidated income statement (See Note 9).

New Revenue Recognition Pronouncement

In May 2014, the FASB issued new accounting guidance to clarify the principles for revenue recognition. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised 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. To achieve that principle, the entity should apply the following steps: identify the contract(s) with the customer, identify the performance obligations in the contract(s), determine the transaction price, allocate the transaction price to the performance obligations in the contract and recognize revenue when (or as) the entity satisfies a performance obligation. The guidance includes requirements to estimate variable or contingent consideration, which will result in revenue being recognized earlier than legacy GAAP. In addition, the guidance requires the capitalization and amortization of certain expenses which were expensed as incurred under legacy GAAP. As discussed in more detail below, the Company expects that once the standard is adopted as of January 1, 2018 revenue will shift among quarters, but does not expect a significant year-over-year impact on annual revenue.

The Company expects there will be significant movement in the quarterly timing of revenue recognition in the Risk and Insurance Services segment. In particular, under the new standard the recognition of revenue in the Company’s reinsurance broking operations will be accelerated from historical patterns. Currently, revenue related to most reinsurance placements is recognized on the later of billing or effective date as premiums are written and attached to the reinsurance treaties. This typically results in revenue being recognized over a 12 to 24 month period. Under the new guidance, revenue will be recognized largely at the policy effective date. In the insurance brokerage operations, revenue from commission based arrangements will continue to be recorded at the policy effective date, while the timing of revenue recognition for certain fee based arrangements will shift among quarters. However since the vast majority of our fee arrangements involve contracts that cover a single year of services, the Company does not believe there will be a significant change to the amount of revenue recognized in an annual period once the standard is adopted.

The Company believes application of the new standard in the Consulting segment will not materially change the existing timing of revenue recognition in quarterly or annual periods. The conclusions will be completed following a final review of customer arrangement legal terms and conditions in certain non-U.S. locations.

The Company expects that certain costs that are currently expensed will be capitalized as costs to obtain or costs to fulfill customer contracts under the new standard. Incremental costs to obtain a contract would generally be amortized over the expected life of the underlying customer relationship under the new guidance. The Company currently expenses those costs as incurred.

In Risk and Insurance Services, certain pre-placement costs will be deferred and "amortized" when the related services are transferred, generally over a period of one year or less. As such, the Company expects the recognition of costs to shift among quarters, but similar to the revenue impact discussed above, does not expect a significant impact on year over year expenses once the standard is adopted.

In several of its businesses, the Company incurs implementation costs necessary to facilitate the delivery of the contracted services. Although certain implementation costs are deferred under current GAAP, the Company has concluded that some additional implementation costs currently expensed under GAAP will be deferred. In addition, the amortization period for these costs will have a longer amortization period which includes the initial contract plus expected renewals. Currently, these deferred implementation costs are amortized over the initial contract term. The Company has not yet fully quantified the impact of the changes discussed above. However, the Company expects that it will recognize a significant amount of contract assets and/or receivables upon implementation of the standard, related to both capitalized costs to obtain and fulfill contracts, as well as commissions related to reinsurance brokerage activity.

The Company is currently designing and implementing changes in processes, controls and systems necessary to support the new revenue recognition requirements.

Entities are permitted to adopt the guidance under one of the following methods: the "full retrospective" method, which applies the guidance to each period presented (prior years restated) or the "modified retrospective" method in which the guidance is only applied to the year of adoption, with the cumulative effect of initially applying the guidance recognized as an adjustment to retained earnings. The Company will adopt the new guidance effective January 1, 2018 and expects to use the modified retrospective method.

New Accounting Pronouncements Recently Adopted

In October 2016, the FASB issued new guidance which changes the evaluation of whether a reporting entity is the primary beneficiary of a variable interest entity by changing how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. If a reporting entity satisfies the first characteristic of a primary beneficiary (such that it is the single decision maker of a variable interest entity), the new guidance requires that reporting entity, in determining whether it satisfies the second characteristic of a primary beneficiary, to include all of its direct variable interest in a variable interest entity and, on a proportionate basis, its indirect variable interests in a variable interest entity held through related parties, including related parties that are under common control with the reporting entity. The adoption of this guidance did not have a significant impact on its financial position, results of operations and statement of cash flows.

In April 2016, the FASB issued new guidance which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. The new guidance requires that companies record all excess tax benefits and tax deficiencies as an income tax benefit or expense in the income statement and classify excess tax benefits as an operating activity in the statement of cash flows. The Company adopted this new guidance prospectively, effective January 1, 2017 and prior periods have not been adjusted. For the nine months ended September 30, 2017, the adoption of this new standard reduced income tax expense in the consolidated statement of income by approximately $58 million. For the nine months ended September 30, 2016, the Company recorded an excess tax benefit of $30 million as an increase to equity in its consolidated balance sheet, which was reflected as cash provided by financing activities in the consolidated statement of cash flows.

In March 2016, the FASB issued new guidance which eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The new guidance is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. The guidance was adopted on January 1, 2017 and did not have an impact on the Company's financial position or results of operations.

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Principles of Consolidation and Other Matters (Policies)

9 Months Ended

Sep. 30, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Accounting

The consolidated financial statements included herein have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission. While certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been omitted pursuant to such rules and regulations for interim filings, the Company believes that the information and disclosures presented are adequate to make such information and disclosures not misleading.

Cash and Cash Equivalents

Cash and cash equivalents primarily consist of certificates of deposit and time deposits, with original maturities of three months or less, and money market funds. The estimated fair value of the Company's cash and cash equivalents approximates their carrying value.

Investments

The Company holds investments in certain private equity funds. Investments in private equity funds are accounted for under the equity method of accounting using a consistently applied three-month lag period adjusted for any known significant changes from the lag period to the reporting date of the Company. The underlying private equity funds follow investment company accounting, where investments within the fund are carried at fair value. Investment gains or losses for the Company's proportionate share of the change in fair value of the funds are recorded in earnings. Investments accounted for using the equity method of accounting are included in other assets in the consolidated balance sheets.

The caption "Investment income (loss)" in the consolidated statements of income comprises realized and unrealized gains and losses from investments recognized in earnings. It includes, when applicable, other than temporary declines in the value of debt and available-for-sale securities and equity method gains or losses on the Company's investments in private equity funds.

Income Taxes

The Company's effective tax rate in the third quarter of 2017 was 26.2% compared with 26.8% in the third quarter of 2016. The effective tax rate for the first nine months of 2017 and 2016 was 25.9% and 28.4%, respectively. The rates reflect foreign operations which are taxed at rates below the U.S. statutory tax rate, including the effect of repatriation, as well as the impact of discrete tax matters such as tax legislation, changes in valuation allowances, nontaxable adjustments to contingent acquisition consideration and, starting in 2017, excess tax benefits related to share-based compensation.

The Company is routinely examined by tax authorities in the jurisdictions in which it has significant operations. The Company regularly considers the likelihood of assessments in each of the taxing jurisdictions resulting from examinations. When evaluating the potential imposition of penalties, the Company considers a number of relevant factors under penalty statutes, including appropriate disclosure of the tax return position, the existence of legal authority supporting the Company's position, and reliance on the opinion of professional tax advisors.

The Company reports a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in tax returns.

Fair Value Measurement

Fair Value Hierarchy

The Company has categorized its assets and liabilities that are valued at fair value on a recurring basis into a three-level fair value hierarchy as defined by the Financial Accounting Standards Board ("FASB"). The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets and liabilities (Level 1) and lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy, for disclosure purposes, is determined based on the lowest level input that is significant to the fair value measurement. Assets and liabilities recorded in the consolidated balance sheets at fair value are categorized based on the inputs in the valuation techniques as follows:

Level 1. Assets and liabilities whose values are based on unadjusted quoted prices for identical assets or liabilities in an active market (examples include active exchange-traded equity securities and exchange-traded money market mutual funds).

Assets and liabilities measured using Level 1 inputs include exchange-traded equity securities, exchange-traded mutual funds and money market funds.

Level 2. Assets and liabilities whose values are based on the following:

a) Quoted prices for similar assets or liabilities in active markets;

b) Quoted prices for identical or similar assets or liabilities in non-active markets (examples include corporate and municipal bonds, which trade infrequently);

c) Pricing models whose inputs are observable for substantially the full term of the asset or liability (examples include most over-the-counter derivatives, including interest rate and currency swaps); and

d) Pricing models whose inputs are derived principally from or corroborated by observable market data through correlation or other means for substantially the full asset or liability (for example, certain mortgage loans).

The Company does not have any assets or liabilities that are measured using Level 2 inputs.

Level 3. Assets and liabilities whose values are based on prices, or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs reflect management’s own assumptions about the assumptions a market participant would use in pricing the asset or liability.

Liabilities measured using Level 3 inputs include liabilities for contingent purchase consideration.

Valuation Techniques

Equity Securities, Money Market Funds and Mutual Funds – Level 1

Investments for which market quotations are readily available are valued at the sale price on their principal exchange or, for certain markets, official closing bid price. Money market funds are valued using a valuation technique that results in price per share at $1.00.

Contingent Purchase Consideration Liability – Level 3

Purchase consideration for some acquisitions made by the Company includes contingent consideration arrangements. These arrangements typically provide for the payment of additional consideration if earnings or revenue targets are met over periods from two to four years. The fair value of the contingent purchase consideration liability is estimated as the present value of future cash flows to be paid, based on projections of revenue and earnings and related targets of the acquired entities.

New Accounting Pronouncements

New Accounting Guidance

In March 2017, the FASB issued new guidance that changes the presentation of net periodic pension cost and net periodic postretirement cost (''net periodic benefit costs"). The new guidance requires employers to report the service cost component of net periodic benefit costs in the same line item as other compensation costs in the income statement. The other components of net periodic benefit costs are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. In addition, only the service cost component is eligible for capitalization, when applicable. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted as of the beginning of an annual period for which financial statements (interim or annual) have not been issued or made available for issuance. The new guidance requires retrospective application for the presentation of the service cost component and the other components of net periodic benefit costs, and prospective application for the capitalization of the service cost component. The adoption of this guidance will impact the presentation of the Company's results of operations, in particular, reducing net operating income, but will have no impact on the Company's net income.

In January 2017, the FASB issued new guidance to simplify the test for goodwill impairment. The new guidance eliminates the second step in the current two-step goodwill impairment process, under which a goodwill impairment loss is measured by comparing the implied fair value of a reporting unit's goodwill with the carrying amount of that goodwill for that reporting unit. The new guidance requires a one-step impairment test, in which the goodwill impairment charge is based on 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. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The guidance should be applied on a prospective basis with the nature of and reason for the change in accounting principle disclosed upon transition. The guidance is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In January 2017, the FASB issued guidance which clarifies the definition of a business in order to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is permitted under certain circumstances and the guidance must be applied prospectively as of the beginning of the period of adoption. The Company is currently evaluating the impact, if any, the adoption of this standard will have on its financial position or results of operations.

In November 2016, the FASB issued new guidance which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. As a result, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented. Early adoption is permitted. The adoption of this guidance is not expected to have an impact on the Company's consolidated balance sheets or consolidated statements of cash flows.

In October 2016, the FASB also issued new guidance which requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance eliminates the exception for an intra-entity transfer of an asset other than inventory. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The new guidance must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The Company does not expect the adoption of this standard to have a material impact on its financial position or results of operations.

In August 2016, the FASB issued new guidance which adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows, including cash payments for debt prepayments or debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investees. The guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The guidance must be applied retrospectively to all periods presented unless retrospective application is impracticable. Early adoption is permitted. The Company does not expect the adoption of this standard to have a significant impact on its statement of cash flows.

In February 2016, the FASB issued new guidance intended to improve financial reporting for leases. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a financing or operating lease. However, unlike current GAAP, which requires that only capital leases be recognized on the balance sheet, the new guidance requires that both types of leases be recognized on the balance sheet. The new guidance will require additional disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, and additional information about the amounts recorded in the financial statements. The accounting by organizations that own the assets ("lessor") leased by the lessee will remain largely unchanged from current GAAP. However, the guidance contains some targeted improvements that are intended to align, where necessary, lessor accounting with the lessee accounting model and with the updated revenue recognition guidance issued in 2014. The new guidance on leases will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early application will be permitted. The Company is currently evaluating the impact the adoption of the guidance will have on its financial position and results of operations, but expects material "right to use" assets and lease liabilities to be recorded on its consolidated balance sheets.

In January 2016, the FASB issued new guidance intended to improve the recognition and measurement of financial instruments. The new guidance requires equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requires a reporting organization to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (also referred to as "own credit") when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company holds certain equity investments that are currently treated as available for sale securities, whereby the mark to market change is recorded to other comprehensive income in its consolidated balance sheet. The adoption of this new standard will impact the Company's results of operations, since the mark to market change to certain of its equity investments will be recorded in the consolidated income statement (See Note 9).

New Revenue Recognition Pronouncement

In May 2014, the FASB issued new accounting guidance to clarify the principles for revenue recognition. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised 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. To achieve that principle, the entity should apply the following steps: identify the contract(s) with the customer, identify the performance obligations in the contract(s), determine the transaction price, allocate the transaction price to the performance obligations in the contract and recognize revenue when (or as) the entity satisfies a performance obligation. The guidance includes requirements to estimate variable or contingent consideration, which will result in revenue being recognized earlier than legacy GAAP. In addition, the guidance requires the capitalization and amortization of certain expenses which were expensed as incurred under legacy GAAP. As discussed in more detail below, the Company expects that once the standard is adopted as of January 1, 2018 revenue will shift among quarters, but does not expect a significant year-over-year impact on annual revenue.

The Company expects there will be significant movement in the quarterly timing of revenue recognition in the Risk and Insurance Services segment. In particular, under the new standard the recognition of revenue in the Company’s reinsurance broking operations will be accelerated from historical patterns. Currently, revenue related to most reinsurance placements is recognized on the later of billing or effective date as premiums are written and attached to the reinsurance treaties. This typically results in revenue being recognized over a 12 to 24 month period. Under the new guidance, revenue will be recognized largely at the policy effective date. In the insurance brokerage operations, revenue from commission based arrangements will continue to be recorded at the policy effective date, while the timing of revenue recognition for certain fee based arrangements will shift among quarters. However since the vast majority of our fee arrangements involve contracts that cover a single year of services, the Company does not believe there will be a significant change to the amount of revenue recognized in an annual period once the standard is adopted.

The Company believes application of the new standard in the Consulting segment will not materially change the existing timing of revenue recognition in quarterly or annual periods. The conclusions will be completed following a final review of customer arrangement legal terms and conditions in certain non-U.S. locations.

The Company expects that certain costs that are currently expensed will be capitalized as costs to obtain or costs to fulfill customer contracts under the new standard. Incremental costs to obtain a contract would generally be amortized over the expected life of the underlying customer relationship under the new guidance. The Company currently expenses those costs as incurred.

In Risk and Insurance Services, certain pre-placement costs will be deferred and "amortized" when the related services are transferred, generally over a period of one year or less. As such, the Company expects the recognition of costs to shift among quarters, but similar to the revenue impact discussed above, does not expect a significant impact on year over year expenses once the standard is adopted.

In several of its businesses, the Company incurs implementation costs necessary to facilitate the delivery of the contracted services. Although certain implementation costs are deferred under current GAAP, the Company has concluded that some additional implementation costs currently expensed under GAAP will be deferred. In addition, the amortization period for these costs will have a longer amortization period which includes the initial contract plus expected renewals. Currently, these deferred implementation costs are amortized over the initial contract term. The Company has not yet fully quantified the impact of the changes discussed above. However, the Company expects that it will recognize a significant amount of contract assets and/or receivables upon implementation of the standard, related to both capitalized costs to obtain and fulfill contracts, as well as commissions related to reinsurance brokerage activity.

The Company is currently designing and implementing changes in processes, controls and systems necessary to support the new revenue recognition requirements.

Entities are permitted to adopt the guidance under one of the following methods: the "full retrospective" method, which applies the guidance to each period presented (prior years restated) or the "modified retrospective" method in which the guidance is only applied to the year of adoption, with the cumulative effect of initially applying the guidance recognized as an adjustment to retained earnings. The Company will adopt the new guidance effective January 1, 2018 and expects to use the modified retrospective method.

New Accounting Pronouncements Recently Adopted

In October 2016, the FASB issued new guidance which changes the evaluation of whether a reporting entity is the primary beneficiary of a variable interest entity by changing how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. If a reporting entity satisfies the first characteristic of a primary beneficiary (such that it is the single decision maker of a variable interest entity), the new guidance requires that reporting entity, in determining whether it satisfies the second characteristic of a primary beneficiary, to include all of its direct variable interest in a variable interest entity and, on a proportionate basis, its indirect variable interests in a variable interest entity held through related parties, including related parties that are under common control with the reporting entity. The adoption of this guidance did not have a significant impact on its financial position, results of operations and statement of cash flows.

In April 2016, the FASB issued new guidance which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. The new guidance requires that companies record all excess tax benefits and tax deficiencies as an income tax benefit or expense in the income statement and classify excess tax benefits as an operating activity in the statement of cash flows. The Company adopted this new guidance prospectively, effective January 1, 2017 and prior periods have not been adjusted. For the nine months ended September 30, 2017, the adoption of this new standard reduced income tax expense in the consolidated statement of income by approximately $58 million. For the nine months ended September 30, 2016, the Company recorded an excess tax benefit of $30 million as an increase to equity in its consolidated balance sheet, which was reflected as cash provided by financing activities in the consolidated statement of cash flows.

In March 2016, the FASB issued new guidance which eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The new guidance is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. The guidance was adopted on January 1, 2017 and did not have an impact on the Company's financial position or results of operations.

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Per Share Data (Tables)

9 Months Ended

Sep. 30, 2017

Earnings Per Share [Abstract]

Diluted EPS Calculation Continuing Operations

Basic net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock.

Diluted net income per share attributable to the Company is calculated by dividing the after-tax income attributable to the Company by the weighted average number of outstanding shares of the Company’s common stock, which have been adjusted for the dilutive effect of potentially issuable common shares.

Basic and Diluted EPS Calculation	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share amounts)	2017		2016		2017		2016
Net income before non-controlling interests	$	397	$	384	$	1,482	$	1,354
Less: Net income attributable to non-controlling interests	4		5		19		22
Net income attributable to the Company	$	393	$	379	$	1,463	$	1,332
Basic weighted average common shares outstanding	512		518		514		520
Dilutive effect of potentially issuable common shares	7		5		6		5
Diluted weighted average common shares outstanding	519		523		520		525
Average stock price used to calculate common stock equivalents	$	79.35	$	66.98	$	75.36	$	62.33

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Supplemental Disclosures to the Consolidated Statements of Cash Flows (Tables)

9 Months Ended

Sep. 30, 2017

Supplemental Cash Flow Information [Abstract]

Additional Information Concerning Acquisitions, Interest and Income Taxes Paid

The following schedule provides additional information concerning acquisitions, interest and income taxes paid for the nine-month periods ended September 30, 2017 and 2016.

(In millions)	2017			2016
Assets acquired, excluding cash	$	852		$	121
Liabilities assumed	(129		)	(4		)
Contingent/deferred purchase consideration	(94		)	(29		)
Net cash outflow for current year acquisitions	$	629		$	88

(In millions)	2017		2016
Interest paid	$	174	$	148
Income taxes paid, net of refunds	$	406	$	417

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Other Comprehensive Income (Loss) (Tables)

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

The changes, net of tax, in the balances of each component of Accumulated Other Comprehensive Income ("AOCI") for the three and nine-month periods ended September 30, 2017 and 2016, including amounts reclassified out of AOCI, are as follows:

(In millions)	Unrealized Investment Gains (Losses)			Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2017	$	30		$	(3,215	)	$	(1,356	)	$	(4,541	)
Other comprehensive (loss) income before reclassifications	(5		)	(173		)	126			(52		)
Amounts reclassified from accumulated other comprehensive income	—			33			—			33
Net current period other comprehensive (loss) income	(5		)	(140		)	126			(19		)
Balance as of September 30, 2017	$	25		$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of July 1, 2016	$	6	$	(2,885	)	$	(1,422	)	$	(4,301	)
Other comprehensive income (loss) before reclassifications	1		36			(54		)	(17		)
Amounts reclassified from accumulated other comprehensive income	—		29			—			29
Net current period other comprehensive income (loss)	1		65			(54		)	12
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2017	$	19	$	(3,232	)	$	(1,880	)	$	(5,093	)
Other comprehensive income (loss) before reclassifications	6		(219		)	650			437
Amounts reclassified from accumulated other comprehensive income	—		96			—			96
Net current period other comprehensive income (loss)	6		(123		)	650			533
Balance as of September 30, 2017	$	25	$	(3,355	)	$	(1,230	)	$	(4,560	)

(In millions)	Unrealized Investment Gains		Pension/Post-Retirement Plans Gains (Losses)			Foreign Currency Translation Gains (Losses)			Total Gains (Losses)
Balance as of January 1, 2016	$	6	$	(3,124	)	$	(1,102	)	$	(4,220	)
Other comprehensive income (loss) before reclassifications	1		214			(374		)	(159		)
Amounts reclassified from accumulated other comprehensive income	—		90			—			90
Net current period other comprehensive income (loss)	1		304			(374		)	(69		)
Balance as of September 30, 2016	$	7	$	(2,820	)	$	(1,476	)	$	(4,289	)

Schedule of Components of Comprehensive Income (Loss)

The components of other comprehensive income (loss) for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

Three Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	127		$	1		$	126		$	(52	)	$	2	$	(54	)
Unrealized investment (losses) gains	(8		)	(3		)	(5		)	1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			1			1		—
Net actuarial losses (a)	43			10			33			41			12		29
Subtotal	43			10			33			42			13		29
Effect of remeasurement	3			—			3			—			—		—
Effect of settlement	1			—			1			—			—		—
Foreign currency translation (losses) gains	(215		)	(38		)	(177		)	40			4		36
Pension/post-retirement plans (losses) gains	(168		)	(28		)	(140		)	82			17		65
Other comprehensive (loss) income	$	(49	)	$	(30	)	$	(19	)	$	31		$	19	$	12
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Income tax credits on prior service cost and net actuarial losses are included in income tax expense.

Nine Months Ended September 30,	2017									2016
(In millions)	Pre-Tax			Tax (Credit)			Net of Tax			Pre-Tax			Tax		Net of Tax
Foreign currency translation adjustments	$	652		$	2		$	650		$	(373	)	$	1	$	(374	)
Unrealized investment gains	11			5			6			1			—		1
Pension/post-retirement plans:
Amortization of losses included in net periodic pension cost:
Prior service cost (a)	—			—			—			2			1		1
Net actuarial losses (a)	125			29			96			125			36		89
Subtotal	125			29			96			127			37		90
Effect of remeasurement	12			3			9			(1		)	—		(1		)
Effect of curtailment	(1		)	—			(1		)	3			1		2
Effect of settlement	2			—			2			1			—		1
Foreign currency translation (losses) gains	(277		)	(49		)	(228		)	253			41		212
Other	(1		)	—			(1		)	—			—		—
Pension/post-retirement plans (losses) gains	(140		)	(17		)	(123		)	383			79		304
Other comprehensive income (loss)	$	523		$	(10	)	$	533		$	11		$	80	$	(69	)
(a) Components of net periodic pension cost are included in compensation and benefits in the consolidated statements of income. Tax on prior service cost and net actuarial losses is included in income tax expense.

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Acquisitions (Tables)

9 Months Ended

Sep. 30, 2017

Business Combinations [Abstract]

Schedule For Allocation of Acquisition Costs

The following table presents the preliminary allocation of the acquisition cost to the assets acquired and liabilities assumed during 2017 based on their fair values:

For the Nine Months Ended September 30, 2017
(In millions)
Cash	$	640
Estimated fair value of deferred/contingent consideration	94
Total Consideration	$	734
Allocation of purchase price:
Cash and cash equivalents	$	11
Accounts receivable, net	17
Property, plant, and equipment	7
Other intangible assets	293
Goodwill	533
Other assets	2
Total assets acquired	863
Current liabilities	21
Other liabilities	108
Total liabilities assumed	129
Net assets acquired	$	734

Schedule of Acquired Finite-Lived Intangible Assets by Major Class

The following chart provides information about other intangible assets acquired during 2017:

	Amount		Weighted Average Amortization Period
Client relationships	$	252	12 years
Other	41		5 years
	$	293

Pro-Forma Information

The unaudited pro-forma financial data is presented for illustrative purposes only and is not necessarily indicative of the operating results that would have been achieved if such acquisitions had occurred on the dates indicated, nor is it necessarily indicative of future consolidated results.

	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions, except per share figures)	2017		2016		2017		2016
Revenue	$	3,349	$	3,256	$	10,416	$	10,232
Net income attributable to the Company	$	392	$	372	$	1,466	$	1,320
Basic net income per share attributable to the Company	$	0.77	$	0.72	$	2.85	$	2.54
Diluted net income per share attributable to the Company	$	0.76	$	0.71	$	2.82	$	2.52

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Goodwill and Other Intangibles (Tables)

9 Months Ended

Sep. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in the Carrying Amount of Goodwill

Changes in the carrying amount of goodwill are as follows:

September 30,
(In millions)	2017		2016
Balance as of January 1, as reported	$	8,369	$	7,889
Goodwill acquired	533		74
Other adjustments(a)	198		12
Balance at September 30,	$	9,100	$	7,975

Amortized Intangible Assets

The gross cost and accumulated amortization at September 30, 2017 and December 31, 2016 are as follows:

	September 30, 2017						December 31, 2016
(In millions)	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Client Relationships	$	1,679	$	487	$	1,192	$	1,390	$	392	$	998
Other (a)	231		103		128		204		76		128
Amortized intangibles	$	1,910	$	590	$	1,320	$	1,594	$	468	$	1,126

^(a) Primarily non-compete agreements, trade names and developed technology.

Estimated Future Aggregate Amortization Expense

The estimated future aggregate amortization expense is as follows:

For the Years Ending December 31,
(In millions)	Estimated Expense
2017 (excludes amortization through September 30, 2017)	$	50
2018	176
2019	166
2020	145
2021	135
Subsequent years	648
	$	1,320

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Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016.

	Identical Assets (Level 1)				Observable Inputs (Level 2)				Unobservable Inputs (Level 3)				Total
(In millions)	09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16		09/30/17		12/31/16
Assets:
Financial instruments owned:
Exchange traded equity securities(a)	$	99	$	89	$	—	$	—	$	—	$	—	$	99	$	89
Mutual funds(a)	143		141		—		—		—		—		143		141
Money market funds(b)	54		22		—		—		—		—		54		22
Total assets measured at fair value	$	296	$	252	$	—	$	—	$	—	$	—	$	296	$	252
Fiduciary Assets:
Money market funds	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Total fiduciary assets measured at fair value	$	50	$	90	$	—	$	—	$	—	$	—	$	50	$	90
Liabilities:
Contingent purchase consideration liability(c)	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241
Total liabilities measured at fair value	$	—	$	—	$	—	$	—	$	170	$	241	$	170	$	241

^(a)  Included in other assets in the consolidated balance sheets.

^(b)  Included in cash and cash equivalents in the consolidated balance sheets.

^(c)  Included in accounts payable and accrued liabilities and other liabilities in the consolidated balance sheets.

Changes in Fair Value of Level 3 Liabilities Representing Acquisition Related Contingent Consideration

The table below sets forth a summary of the changes in fair value of the Company’s Level 3 liabilities as of September 30, 2017 and 2016 that represent contingent consideration related to acquisitions:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Balance at beginning of period,	$	203		$	279		$	241		$	309
Additions	2			1			36			9
Payments	(42		)	(35		)	(107		)	(85		)
Revaluation Impact	5			(13		)	(3		)	5
Other (a)	2			—			3			(6		)
Balance at September 30,	$	170		$	232		$	170		$	232

^(a) Primarily reflects the impact of foreign exchange.

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Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2017

Defined Benefit Plan [Abstract]

Schedule of Net Benefit Costs

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	17		$	—	$	1
Interest cost	59			66			1		—
Expected return on plan assets	(143		)	(137		)	—		—
Amortization of prior service cost	—			1			—		—
Recognized actuarial loss	33			24			—		—
Net periodic benefit (credit) cost	$	(32	)	$	(29	)	$	1	$	1
Settlement loss	1			—			—		—
Total (credit) cost	$	(31	)	$	(29	)	$	1	$	1

Significant non-U.S. plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	56		$	54		$	—		$	1
Interest cost	173			209			2			2
Expected return on plan assets	(418		)	(430		)	—			—
Amortization of prior service credit	(1		)	—			(1		)	—
Recognized actuarial loss	97			72			1			—
Net periodic benefit (credit) cost	$	(93	)	$	(95	)	$	2		$	3
Curtailment gain	(1		)	(5		)	—			—
Settlement loss	2			1			—			—
Total (credit) cost	$	(92	)	$	(99	)	$	2		$	3

The components of the net periodic benefit cost for defined benefit and other post-retirement plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	19		$	43		$	—	$	1
Interest cost	125			132			1		—
Expected return on plan assets	(232		)	(232		)	—		—
Amortization of prior service cost	—			1			1		1
Recognized actuarial loss	42			43			—		—
Net periodic benefit (credit) cost	$	(46	)	$	(13	)	$	2	$	2
Settlement loss	1			—			—		—
Total (credit) cost	$	(45	)	$	(13	)	$	2	$	2
Combined U.S. and significant non-U.S. plans	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	56		$	133		$	—	$	1
Interest cost	371			407			3		3
Expected return on plan assets	(686		)	(715		)	—		—
Amortization of prior service (credit) cost	(1		)	—			2		3
Recognized actuarial loss (gain)	125			127			—		(1		)
Net periodic benefit (credit) cost	$	(135	)	$	(48	)	$	5	$	6
Curtailment gain	(1		)	(5		)	—		—
Settlement loss	2			1			—		—
Total (credit) cost	$	(134	)	$	(52	)	$	5	$	6
U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Three Months Ended September 30,
(In millions)	2017			2016			2017		2016
Service cost	$	—		$	26		$	—	$	—
Interest cost	66			66			—		—
Expected return on plan assets	(89		)	(95		)	—		—
Amortization of prior service cost	—			—			1		1
Recognized actuarial loss	9			19			—		—
Net periodic benefit (credit) cost	$	(14	)	$	16		$	1	$	1

U.S. Plans only	Pension Benefits						Post-retirement Benefits
For the Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Service cost	$	—		$	79		$	—		$	—
Interest cost	198			198			1			1
Expected return on plan assets	(268		)	(285		)	—			—
Amortization of prior service cost	—			—			3			3
Recognized actuarial loss (gain)	28			55			(1		)	(1		)
Net periodic benefit (credit) cost	$	(42	)	$	47		$	3		$	3

Schedule of Assumptions Used

The weighted average actuarial assumptions utilized to calculate the net periodic benefit costs for the U.S. and significant non-U.S. defined benefit plans are as follows:

Combined U.S. and significant non-U.S. plans	Pension Benefits				Post-retirement Benefits
September 30,	2017		2016		2017		2016
Weighted average assumptions:
Expected return on plan assets	6.64	%	7.07	%	—		—
Discount rate	3.40	%	4.11	%	3.64	%	4.12	%
Rate of compensation increase*	1.77	%	2.44	%	—		—

*The 2017 assumption does not include a rate of compensation increase for the U.S. defined benefit plans since future benefit accruals were discontinued for those plans after December 31, 2016.

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Debt (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Schedule of Outstanding Debt

The Company’s outstanding debt is as follows:

(In millions)	September 30, 2017		December 31, 2016
Short-term:
Commercial paper	$	—	$	50
Current portion of long-term debt	13		262
	13		312
Long-term:
Senior notes – 2.30% due 2017	—		250
Senior notes – 2.55% due 2018	250		249
Senior notes – 2.35% due 2019	299		299
Senior notes – 2.35% due 2020	498		497
Senior notes – 4.80% due 2021	498		498
Senior notes – 2.75% due 2022	496		—
Senior notes – 3.30% due 2023	347		347
Senior notes – 4.05% due 2023	248		248
Senior notes – 3.50% due 2024	596		596
Senior notes – 3.50% due 2025	496		495
Senior notes – 3.75% due 2026	596		596
Senior notes – 5.875% due 2033	297		297
Senior notes – 4.35% due 2047	492		—
Mortgage – 5.70% due 2035	373		382
Other	2		3
	5,488		4,757
Less current portion	13		262
	$	5,475	$	4,495

Estimated Fair Value Of Significant Financial Instruments

The estimated fair value of the Company’s short-term and long-term debt is provided below. Certain estimates and judgments were required to develop the fair value amounts. The fair value amounts shown below are not necessarily indicative of the amounts that the Company would realize upon disposition, nor do they indicate the Company’s intent or need to dispose of the financial instrument.

	September 30, 2017				December 31, 2016
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Short-term debt	$	13	$	13	$	312	$	313
Long-term debt	$	5,475	$	5,720	$	4,495	$	4,625

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Restructuring Costs (Tables)

9 Months Ended

Sep. 30, 2017

Restructuring and Related Activities [Abstract]

Restructuring Activities

Details of the restructuring activity from January 1, 2016 through September 30, 2017, which includes liabilities from actions prior to 2017, are as follows:

(In millions)	Liability at 1/1/16		Amounts Accrued		Cash Paid			Other			Liability at 12/31/16		Amounts Accrued		Cash Paid			Other		Liability at 9/30/17
Severance	$	15	$	40	$	(22	)	$	(1	)	$	32	$	24	$	(42	)	$	—	$	14
Future rent under non-cancelable leases and other costs	78		4		(17		)	(4		)	61		8		(15		)	1		55
Total	$	93	$	44	$	(39	)	$	(5	)	$	93	$	32	$	(57	)	$	1	$	69

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Segment Information (Tables)

9 Months Ended

Sep. 30, 2017

Segment Reporting [Abstract]

Selected Information And Details For MMC's Operating Segments

Selected information about the Company’s operating segments for the three and nine-month periods ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,							Nine Months Ended September 30,
(In millions)	Revenue				Operating Income (Loss)			Revenue				Operating Income (Loss)
2017–
Risk and Insurance Services	$	1,763		(a)	$	314		$	5,668		(c)	$	1,455
Consulting	1,587			(b)	329			4,705			(d)	853
Total Operating Segments	3,350				643			10,373				2,308
Corporate / Eliminations	(9		)		(46		)	(34		)		(138		)
Total Consolidated	$	3,341			$	597		$	10,339			$	2,170
2016–
Risk and Insurance Services	$	1,632		(a)	$	315		$	5,350		(c)	$	1,340
Consulting	1,513			(b)	308			4,530			(d)	838
Total Operating Segments	3,145				623			9,880				2,178
Corporate / Eliminations	(10		)		(51		)	(33		)		(147		)
Total Consolidated	$	3,135			$	572		$	9,847			$	2,031

^(a)  Includes inter-segment revenue of $1 million in both 2017and2016, interest income on fiduciary funds of $11 million and $8 million in 2017 and 2016, respectively, and equity method income of $2 million and $4 million in 2017 and 2016, respectively.

^(b)  Includes inter-segment revenue of $8 million and $9 million in 2017 and 2016, respectively, interest income on fiduciary funds of $2 million in 2017 and $1 million in 2016, respectively, and equity method income of $3 million in 2017 and $5 million in 2016, respectively.

^(c)  Includes inter-segment revenue of $5 million in both 2017 and2016, interest income on fiduciary funds of $28 million and $20 million in 2017 and 2016, respectively, and equity method income of $11 million in both 2017 and 2016.

^(d)  Includes inter-segment revenue of $29 million and $28 million in 2017 and 2016, respectively, interest income on fiduciary funds of $3 million in 2017 and $2 million in 2016, respectively, and equity method income of $12 million in 2017 and $14 million in 2016, respectively.

Details of Operating Segment Revenue

Details of operating segment revenue for the three and nine-month period ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2017			2016			2017			2016
Risk and Insurance Services
Marsh	$	1,490		$	1,370		$	4,713		$	4,427
Guy Carpenter	273			262			955			923
Total Risk and Insurance Services	1,763			1,632			5,668			5,350
Consulting
Mercer	1,149			1,109			3,335			3,227
Oliver Wyman Group	438			404			1,370			1,303
Total Consulting	1,587			1,513			4,705			4,530
Total Operating Segments	3,350			3,145			10,373			9,880
Corporate / Eliminations	(9		)	(10		)	(34		)	(33		)
Total	$	3,341		$	3,135		$	10,339		$	9,847

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Nature of Operations (Details) $ in Billions	9 Months Ended
	Sep. 30, 2017 USD ($) segment
Segment Reporting Information [Line Items]
Number of business segments | segment	2
Mercer Consulting Group
Segment Reporting Information [Line Items]
Assets under management | $	$ 210

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Principles of Consolidation And Other Matters (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating funds related to regulatory requirements or as collateral under captive insurance arrangements	$ 184,000,000		$ 184,000,000
Equity method investments lag period			3 months
Investment income		$ 1,000,000	$ 3,000,000
Investment loss	$ (2,000,000)			$ (2,000,000)
Effective tax rate (as a percent)	26.20%	26.80%	25.90%	28.40%
Unrecognized tax benefits	$ 64,000,000		$ 64,000,000		$ 65,000,000
Minimum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	0		0
Maximum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	$ 9,000,000		$ 9,000,000

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Fiduciary Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fiduciary Assets and Liabilities [Line Items]
Net uncollected premiums and claims receivable and payable	$ 6,800		$ 6,800		$ 7,000
Operating Segments | Risk and Insurance Services Segment
Fiduciary Assets and Liabilities [Line Items]
Interest on fiduciary funds (less than)	11	$ 8	28	$ 20
Operating Segments | Consulting Segment
Fiduciary Assets and Liabilities [Line Items]
Interest on fiduciary funds (less than)	$ 2	$ 1	$ 3	$ 2

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Per Share Data (Basic and Diluted EPS Calculation Continuing Operations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income before non-controlling interests	$ 397	$ 384	$ 1,482	$ 1,354
Less: Net income attributable to non-controlling interests	4	5	19	22
Net income attributable to the Company	$ 393	$ 379	$ 1,463	$ 1,332
Basic weighted average common shares outstanding (in shares)	512.0	518.0	514.0	520.0
Dilutive effect of potentially issuable common shares (in shares)	7.0	5.0	6.0	5.0
Diluted weighted average common shares outstanding (in shares)	519.0	523.0	520.0	525.0
Average stock price used to calculate common stock equivalents (in dollars per share)	$ 79.35	$ 66.98	$ 75.36	$ 62.33
Stock options outstanding (in shares)	11.3	13.6	11.3	13.6

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Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 852	$ 121
Liabilities assumed	(129)	(4)
Contingent/deferred purchase consideration	(94)	(29)
Net cash outflow for current year acquisitions	629	88
Interest paid	174	148
Income taxes paid, net of refunds	$ 406	$ 417

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Supplemental Disclosures to the Consolidated Statements of Cash Flows (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Disclosure to the Consolidate Statements of Cash Flows [Line Items]
Deferred and contingent consideration from prior years acquisition	$ 127	$ 96
Contingent consideration from prior year's acquisitions	80	43
Net charge for adjustments related to acquisition related accounts	(3)	5
Payment of contingent consideration	27	42
Non-cash issuance of common stock	88	71
Stock-based compensation expense, equity awards	111	84
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount	(58)
Adjustments to additional paid in capital, income tax benefit from share-based compensation		30
Prior Fiscal Periods Acquisitions
Supplemental Disclosure to the Consolidate Statements of Cash Flows [Line Items]
Deferred purchase consideration from prior years' acquisitions	47	53
Contingent consideration from prior year's acquisitions	$ 107	$ 85

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Other Comprehensive Income (Loss) (Schedule of Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive (loss) income, net of tax	$ (19)	$ 12	$ 533	$ (69)
Unrealized Investment Gains
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	30	6	19	6
Other comprehensive (loss) income before reclassifications	(5)	1	6	1
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive (loss) income, net of tax	(5)	1	6	1
Balance, ending of period	25	7	25	7
Pension/Postretirement Plans Gains (Losses)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(3,215)	(2,885)	(3,232)	(3,124)
Other comprehensive (loss) income before reclassifications	(173)	36	(219)	214
Amounts reclassified from accumulated other comprehensive income	33	29	96	90
Other comprehensive (loss) income, net of tax	(140)	65	(123)	304
Balance, ending of period	(3,355)	(2,820)	(3,355)	(2,820)
Foreign Currency Translation Gains (Losses)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(1,356)	(1,422)	(1,880)	(1,102)
Other comprehensive (loss) income before reclassifications	126	(54)	650	(374)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive (loss) income, net of tax	126	(54)	650	(374)
Balance, ending of period	(1,230)	(1,476)	(1,230)	(1,476)
AOCI Attributable to Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(4,541)	(4,301)	(5,093)	(4,220)
Other comprehensive (loss) income before reclassifications	(52)	(17)	437	(159)
Amounts reclassified from accumulated other comprehensive income	33	29	96	90
Other comprehensive (loss) income, net of tax	(19)	12	533	(69)
Balance, ending of period	$ (4,560)	$ (4,289)	$ (4,560)	$ (4,289)

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Other Comprehensive Income (Loss) (Schedule Of Components Of Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Foreign currency translation adjustments, Pre-Tax		$ 127	$ (52)	$ 652	$ (373)
Foreign currency translation adjustments, Tax		1	2	2	1
Foreign currency translation adjustments, Net of Tax		126	(54)	650	(374)
Unrealized investment gains (losses), Pre-Tax		(8)	1	11	1
Unrealized investment gains (losses), Tax		(3)	0	5	0
Unrealized investment gains (losses), Net of Tax		(5)	1	6	1
Pension/post-retirement plans:
Prior services losses (gains), Pre-Tax	[1]	0	1	0	2
Prior service losses (gains), Tax	[1]	0	1	0	1
Prior Service losses (gains), Net of Tax	[1]	0	0	0	1
Net actuarial loss, Pre-Tax	[1]	43	41	125	125
Net actuarial loss, Tax	[1]	10	12	29	36
Net actuarial loss, Net of Tax	[1]	33	29	96	89
Subtotal, Pre-Tax		43	42	125	127
Subtotal, Tax		10	13	29	37
Subtotal, Net of Tax		33	29	96	90
Effect of remeasurement, Pre-tax		3	0	12	(1)
Effect of remeasurement, Tax		0	0	3	0
Effect of remeasurement, Net of Tax		3	0	9	(1)
Effect of curtailment, Pre-Tax				(1)	3
Effect of curtailment, Tax				0	1
Effect of curtailment, Net of Tax				(1)	2
Effect of settlement, Pre-tax		1	0	2	1
Effect of settlement, Tax		0	0	0	0
Effect of settlement, Net of Tax		1	0	2	1
Foreign currency translation adjustment, Pre-Tax		(215)	40	(277)	253
Foreign currency translation adjustment, Tax		(38)	4	(49)	41
Foreign currency translation adjustment, Net of Tax		(177)	36	(228)	212
Other, Pre-Tax				(1)	0
Other, Tax				0	0
Other, Net of Tax				(1)	0
Pension/post-retirement plans (losses) gains, Pre-Tax		(168)	82	(140)	383
Pension/post-retirement plans (losses) gains, Tax		(28)	17	(17)	79
Pension/post-retirement plans (losses) gains, Net of Tax		(140)	65	(123)	304
Other comprehensive (loss) income, before tax		(49)	31	523	11
Other comprehensive income (loss), Tax		(30)	19	(10)	80
Other comprehensive (loss) income, net of tax		$ (19)	$ 12	$ 533	$ (69)

[1] Components of net periodic pension cost are included in compensation and benefits in the Consolidated Statements of Income. Tax on prior service gains and net actuarial losses is included in income tax expense.

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Acquisitions (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($) acquisition	Sep. 30, 2016 USD ($)	Dec. 31, 2016 acquisition
Business Acquisition [Line Items]
Total consideration		$ 734	$ 119
Cash		640	90
Estimated fair value of deferred/contingent consideration		94	29
Contingent consideration from prior year's acquisitions		80	43
Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Total consideration		734
Cash		640
Estimated fair value of deferred/contingent consideration		94
Revenue related to acquisitions	$ 40	103
Operating income related to acquisitions	$ (1)	16
Prior Fiscal Periods Acquisitions
Business Acquisition [Line Items]
Deferred purchase consideration from prior years' acquisitions		47	53
Contingent consideration from prior year's acquisitions		$ 107	$ 85
Risk and Insurance Services Segment
Business Acquisition [Line Items]
Number of acquisitions made (in acquisitions) | acquisition		7		9
Consulting Segment
Business Acquisition [Line Items]
Number of acquisitions made (in acquisitions) | acquisition		1		6
Minimum
Business Acquisition [Line Items]
Revenue target period (in years)		2 years
Minimum | Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Revenue target period (in years)		2 years
Maximum
Business Acquisition [Line Items]
Revenue target period (in years)		4 years
Maximum | Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Revenue target period (in years)		4 years

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Acquisitions (Allocation Of Acquisition Costs) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Cash	$ 640	$ 90
Estimated fair value of deferred/contingent consideration	94	29
Total Consideration	734	119
Allocation of purchase price:
Goodwill	9,100	$ 7,975	$ 8,369	$ 7,889
Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Cash	640
Estimated fair value of deferred/contingent consideration	94
Total Consideration	734
Allocation of purchase price:
Cash and cash equivalents	11
Accounts receivable, net	17
Property, plant, and equipment	7
Other intangible assets	293
Goodwill	533
Other assets	2
Total assets acquired	863
Current liabilities	21
Other liabilities	108
Total liabilities assumed	129
Net assets acquired	$ 734

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Acquisitions (Acquired Finite-Lived Intangible Assets) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 293
Client relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 252
Finite-lived intangible assets, remaining amortization period	12 years
Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 41
Finite-lived intangible assets, remaining amortization period	5 years

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Acquisitions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Combinations [Abstract]
Revenue	$ 3,349	$ 3,256	$ 10,416	$ 10,232
Net income attributable to the Company	$ 392	$ 372	$ 1,466	$ 1,320
Basic net income per share:
Basic net income per share attributable to the Company (in dollars per share)	$ 0.77	$ 0.72	$ 2.85	$ 2.54
Diluted net income per share:
Diluted net income per share attributable to the Company (in dollars per share)	$ 0.76	$ 0.71	$ 2.82	$ 2.52

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Goodwill and Other Intangibles (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Goodwill	$ 9,100	$ 7,975	$ 8,369	$ 7,889
Aggregate amortization expense	122	$ 99
Risk and Insurance Services Segment
Segment Reporting Information [Line Items]
Goodwill	6,500
Consulting Segment
Segment Reporting Information [Line Items]
Goodwill	$ 2,600

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Goodwill and Other Intangibles (Changes in the Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
Balance as of January 1, as reported		$ 8,369	$ 7,889
Goodwill acquired		533	74
Other adjustments	[1]	198	12
Balance at September 30,		$ 9,100	$ 7,975

[1] (a) The increase in 2017 primarily reflects the impact of foreign exchange.

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Goodwill and Other Intangibles (Amortized Intangible Assets) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Cost		$ 1,910	$ 1,594
Accumulated Amortization		590	468
Net Carrying Amount		1,320	1,126
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Cost		1,679	1,390
Accumulated Amortization		487	392
Net Carrying Amount		1,192	998
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Cost	[1]	231	204
Accumulated Amortization	[1]	103	76
Net Carrying Amount	[1]	$ 128	$ 128

[1] Primarily non-compete agreements, trade names and developed technology.

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Goodwill And Other Intangibles (Estimated Future Aggregate Amortization Expense) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
2017 (excludes amortization through September 30, 2017)	$ 50
2018	176
2019	166
2020	145
2021	135
Subsequent years	648
Net Carrying Amount	$ 1,320	$ 1,126

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Fair Value Measurements (Narrative) (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($)	Sep. 30, 2017 ZAR / shares	Apr. 30, 2017 ZAR / shares	Jan. 01, 2017 ZAR / shares	Dec. 31, 2016 USD ($)	Feb. 24, 2015 USD ($)	Dec. 31, 2014 ZAR / shares
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjustments to acquisition related contingent consideration liability			$ (3)
Increase in fair value of contingent consideration due to 5% increase in projections			18
Decrease in fair value of contingent consideration due to 5% decrease in projections			19
Carrying value of investment	$ 405		405					$ 389
Unrealized investment (losses) gains	(8)	$ 1	$ 11	$ 1
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)			2 years
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)			4 years
Private Equity Funds, Foreign
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment	72		$ 72					$ 79
Alexander Forbes Group Holdings Limited
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) | ZAR / shares					ZAR 6.75					ZAR 7.50
Carrying value of investment	$ 268		$ 268
Percentage of ownership in equity investment	33.00%		33.00%
Investment shares owned | shares	443		443
Market value of investment	$ 225		$ 225
Share price, percentage of cost basis	90.00%		90.00%
Share price, weighted average (per share amount) | ZAR / shares					ZAR 6.75
Alexander Forbes Group Holdings Limited | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) | (per share)	$ 6.40		$ 6.40			ZAR 5.99
Share price, percentage of purchase price	85.00%		85.00%
Alexander Forbes Group Holdings Limited | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) | (per share)	$ 7.28		$ 7.28				ZAR 7.89
Share price, percentage of purchase price	97.00%		97.00%
Benefitfocus
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Market value of investment	$ 95		$ 95
Percentage of business interest acquired									9.90%
Total consideration									$ 75
Unrealized investment (losses) gains			$ 11
Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) | $ / shares	$ 1.00		$ 1.00

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Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Financial instruments owned:
Total assets measured at fair value		$ 296	$ 252
Fiduciary Assets:
Fiduciary assets		50	90
Liabilities:
Total liabilities measured at fair value		170	241
Identical Assets (Level 1)
Financial instruments owned:
Total assets measured at fair value		296	252
Fiduciary Assets:
Fiduciary assets		50	90
Liabilities:
Total liabilities measured at fair value		0	0
Observable Inputs (Level 2)
Financial instruments owned:
Total assets measured at fair value		0	0
Fiduciary Assets:
Fiduciary assets		0	0
Liabilities:
Total liabilities measured at fair value		0	0
Unobservable Inputs (Level 3)
Financial instruments owned:
Total assets measured at fair value		0	0
Fiduciary Assets:
Fiduciary assets		0	0
Liabilities:
Total liabilities measured at fair value		170	241
Money Market Funds
Fiduciary Assets:
Fiduciary assets		50	90
Money Market Funds | Identical Assets (Level 1)
Fiduciary Assets:
Fiduciary assets		50	90
Money Market Funds | Observable Inputs (Level 2)
Fiduciary Assets:
Fiduciary assets		0	0
Money Market Funds | Unobservable Inputs (Level 3)
Fiduciary Assets:
Fiduciary assets		0	0
Other Assets
Financial instruments owned:
Exchange traded equity securities	[1]	99	89
Mutual funds	[1]	143	141
Other Assets | Identical Assets (Level 1)
Financial instruments owned:
Exchange traded equity securities	[1]	99	89
Mutual funds	[1]	143	141
Other Assets | Observable Inputs (Level 2)
Financial instruments owned:
Exchange traded equity securities	[1]	0	0
Mutual funds	[1]	0	0
Other Assets | Unobservable Inputs (Level 3)
Financial instruments owned:
Exchange traded equity securities	[1]	0	0
Mutual funds	[1]	0	0
Cash and Cash Equivalents
Financial instruments owned:
Money market funds	[2]	54	22
Cash and Cash Equivalents | Identical Assets (Level 1)
Financial instruments owned:
Money market funds	[2]	54	22
Cash and Cash Equivalents | Observable Inputs (Level 2)
Financial instruments owned:
Money market funds	[2]	0	0
Cash and Cash Equivalents | Unobservable Inputs (Level 3)
Financial instruments owned:
Money market funds	[2]	0	0
Accounts Payable and Accrued Liabilities and Other Liabilities
Liabilities:
Contingent purchase consideration liability	[3]	170	241
Accounts Payable and Accrued Liabilities and Other Liabilities | Identical Assets (Level 1)
Liabilities:
Contingent purchase consideration liability	[3]	0	0
Accounts Payable and Accrued Liabilities and Other Liabilities | Observable Inputs (Level 2)
Liabilities:
Contingent purchase consideration liability	[3]	0	0
Accounts Payable and Accrued Liabilities and Other Liabilities | Unobservable Inputs (Level 3)
Liabilities:
Contingent purchase consideration liability	[3]	$ 170	$ 241

[1] Included in other assets in the consolidated balance sheets.

[2] Included in cash and cash equivalents in the consolidated balance sheets.

[3] Included in accounts payable and accrued liabilities and other liabilities in the consolidated balance sheets.

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Fair Value Measurements (Changes In Fair Value Of Level 3 Liabilities Representing Acquisition Related Contingent Consideration) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Revaluation Impact				$ (3)	$ 5
Contingent Consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period,		$ 203	$ 279	241	309
Additions		2	1	36	9
Payments		(42)	(35)	(107)	(85)
Revaluation Impact		5	(13)	(3)	5
Other	[1]	2	0	3	(6)
Balance at September 30,		$ 170	$ 232	$ 170	$ 232

[1] (a) Primarily reflects the impact of foreign exchange.

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Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Oct. 31, 2016	Sep. 30, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of employees' gross pay (up to)	4.00%
Maximum annual contributions per employee, percent	7.00%
Contributions by employer		$ 193
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in current fiscal year		63
United States
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized		$ 99
United States | Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage		64.00%
Actual asset allocation percentage of equity		65.00%
United States | Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage		36.00%
Actual asset allocation percentage of equity		35.00%
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized		$ 56
United Kingdom | Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage			46.00%
Actual asset allocation percentage of equity		47.00%
United Kingdom | Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage			54.00%
Actual asset allocation percentage of equity		53.00%
United Kingdom | Geographic Concentration Risk | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Concentration risk percentage		81.00%

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Retirement Benefits (Schedule Of Defined Benefit Plan Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 19	$ 43	$ 56	$ 133
Interest cost	125	132	371	407
Expected return on plan assets	(232)	(232)	(686)	(715)
Amortization of prior service cost	0	1	(1)	0
Recognized actuarial loss (gain)	42	43	125	127
Net periodic benefit (credit) cost	(46)	(13)	(135)	(48)
Curtailment gain (loss)			(1)	(5)
Settlement loss	1	0	2	1
Total (credit) cost	(45)	(13)	(134)	(52)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	1	0	3	3
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	1	1	2	3
Recognized actuarial loss (gain)	0	0	0	(1)
Net periodic benefit (credit) cost	2	2	5	6
Curtailment gain (loss)			0	0
Settlement loss	0	0	0	0
Total (credit) cost	2	2	5	6
Domestic Plan | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	26	0	79
Interest cost	66	66	198	198
Expected return on plan assets	(89)	(95)	(268)	(285)
Amortization of prior service cost	0	0	0	0
Recognized actuarial loss (gain)	9	19	28	55
Net periodic benefit (credit) cost	(14)	16	(42)	47
Domestic Plan | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	0	0	1	1
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	1	1	3	3
Recognized actuarial loss (gain)	0	0	(1)	(1)
Net periodic benefit (credit) cost	1	1	3	3
Foreign Plan | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	19	17	56	54
Interest cost	59	66	173	209
Expected return on plan assets	(143)	(137)	(418)	(430)
Amortization of prior service cost	0	1	(1)	0
Recognized actuarial loss (gain)	33	24	97	72
Net periodic benefit (credit) cost	(32)	(29)	(93)	(95)
Curtailment gain (loss)			(1)	(5)
Settlement loss	1	0	2	1
Total (credit) cost	(31)	(29)	(92)	(99)
Foreign Plan | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	1	0	2	2
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	(1)	0
Recognized actuarial loss (gain)	0	0	1	0
Net periodic benefit (credit) cost	1	1	2	3
Curtailment gain (loss)			0	0
Settlement loss	0	0	0	0
Total (credit) cost	$ 1	$ 1	$ 2	$ 3

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Retirement Benefits (Schedule Of Defined Benefit Plan Weighted Average Assumption Used In Calculating Net Periodic Benefit Cost) (Details)		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Weighted average assumptions:
Expected return on plan assets		6.64%	7.07%
Discount rate		3.40%	4.11%
Rate of compensation increase	[1]	1.77%	2.44%
Postretirement Benefits
Weighted average assumptions:
Expected return on plan assets		0.00%	0.00%
Discount rate		3.64%	4.12%
Rate of compensation increase	[1]	0.00%	0.00%

[1] *The 2017 assumption does not include a rate of compensation increase for the U.S. defined benefit plans since future benefit accruals were discontinued for those plans after December 31, 2016.

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Debt (Schedule Of Outstanding Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Jan. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Commercial paper outstanding	$ 0		$ 50
Current portion of long-term debt	13		262
Short-term debt	13		312
Long-term debt, current and noncurrent	5,488		4,757
Long-term debt	5,475		4,495
2.30% Senior Debt Obligations Due 2017
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 0		250
Interest rate	2.30%
2.55% Senior Debt Obligations Due 2018
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 250		249
Interest rate	2.55%
2.35% Senior Debt Obligations Due 2019
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 299		299
Interest rate	2.35%
2.35% Senior Debt Obligations Due 2020
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 498		497
Interest rate	2.35%
4.80% Senior Debt Obligations Due 2021
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 498		498
Interest rate	4.80%
2.75% Senior Debt Obligations Due 2022
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 496		0
Interest rate	2.75%	2.75%
3.30% Senior Debt Obligations Due 2023
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 347		347
Interest rate	3.30%			3.30%
4.05% Senior Debt Obligations Due 2023
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 248		248
Interest rate	4.05%
3.50% Senior Debt Obligations Due 2024
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 596		596
Interest rate	3.50%
3.50% Senior Debt Obligations Due 2025
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 496		495
Interest rate	3.50%
3.75% Senior Debt Obligations Due 2026
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 596		596
Interest rate	3.75%
5.875% Senior Debt Obligations Due 2033
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 297		297
Interest rate	5.875%
4.35% Senior Debt Obligation Due 2047
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 492		0
Interest rate	4.35%	4.35%
Mortgage Due 2035
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 373		382
Interest rate	5.70%
Other
Debt Instrument [Line Items]
Long-term debt, current and noncurrent	$ 2		$ 3

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Debt (Narrative) (Details) - USD ($)	1 Months Ended		9 Months Ended
	Apr. 30, 2017	Mar. 31, 2016	Sep. 30, 2017	Jan. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Commercial paper outstanding			$ 0		$ 50,000,000
Repayments of senior debt	$ 250,000,000
2.75% Senior Debt Obligations Due 2022
Debt Instrument [Line Items]
Interest rate			2.75%	2.75%
Proceeds from issuance of debt				$ 500,000,000
4.35% Senior Debt Obligation Due 2047
Debt Instrument [Line Items]
Interest rate			4.35%	4.35%
Proceeds from issuance of debt				$ 500,000,000
3.30% Senior Debt Obligations Due 2023
Debt Instrument [Line Items]
Interest rate		3.30%	3.30%
Proceeds from issuance of debt		$ 350,000,000
Term of debt		7 years
Amended Revolving Credit Facility March 27, 2014
Debt Instrument [Line Items]
Term of debt			5 years
Debt facilities, maximum borrowing capacity			$ 1,500,000,000
Revolving credit facility, amount outstanding			0
Commercial Paper
Debt Instrument [Line Items]
Borrowings under uncommited bank credit line			$ 1,500,000,000

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Debt (Estimated Fair Value of Significant Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term debt	$ 13	$ 312
Long-term debt	5,475	4,495
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term debt	13	313
Long-term debt	$ 5,720	$ 4,625

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Restructuring Costs (Restructuring Activities) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Liability at beginning of period	$ 93	$ 93
Amounts Accrued	32	44
Cash Paid	(57)	(39)
Other	1	(5)
Liability at end of period	69	93
Severance
Restructuring Reserve [Roll Forward]
Liability at beginning of period	32	15
Amounts Accrued	24	40
Cash Paid	(42)	(22)
Other	0	(1)
Liability at end of period	14	32
Future rent under non-cancelable leases and other costs
Restructuring Reserve [Roll Forward]
Liability at beginning of period	61	78
Amounts Accrued	8	4
Cash Paid	(15)	(17)
Other	1	(4)
Liability at end of period	55	$ 61
Operating Segments | Risk and Insurance Services Segment | Acquisition Related
Restructuring Reserve [Roll Forward]
Amounts Accrued	7
Operating Segments | Consulting Segment | Acquisition Related
Restructuring Reserve [Roll Forward]
Amounts Accrued	18
Corporate | Acquisition Related
Restructuring Reserve [Roll Forward]
Amounts Accrued	$ 7

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Common Stock (Details) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Nov. 30, 2016
Equity, Class of Treasury Stock [Line Items]
Payments for repurchase of common stock	$ 600	$ 625
Stock-based compensation, shares issued during period	4.6	4.5
Common Stock
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased (in shares)	8.0	10.0
Payments for repurchase of common stock	$ 600	$ 625
Share repurchases program, authorized amount (up to)			$ 2,500
Stock repurchase program, remaining authorized repurchase amount	$ 1,800

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Claims, Lawsuits And Other Contingencies (Details) £ in Millions	Sep. 30, 2017 GBP (£)
Other Contingencies-Guarantees
Loss Contingencies [Line Items]
Amount reinsured by third party (up to)	£ 40

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Segment Information (Selected Information And Details For MMC's Operating Segments) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 3,341		$ 3,135		$ 10,339		$ 9,847
Operating Income (Loss)	597		572		2,170		2,031
Operating Segments
Segment Reporting Information [Line Items]
Revenue	3,350		3,145		10,373		9,880
Operating Income (Loss)	643		623		2,308		2,178
Operating Segments | Risk and Insurance Services Segment
Segment Reporting Information [Line Items]
Revenue	1,763	[1]	1,632	[1]	5,668	[2]	5,350	[2]
Operating Income (Loss)	314		315		1,455		1,340
Interest on fiduciary funds (less than)	11		8		28		20
Equity method income	2		4		11		11
Operating Segments | Consulting Segment
Segment Reporting Information [Line Items]
Revenue	1,587	[3]	1,513	[3]	4,705	[4]	4,530	[4]
Operating Income (Loss)	329		308		853		838
Interest on fiduciary funds (less than)	2		1		3		2
Equity method income	3		5		12		14
Corporate and Eliminations
Segment Reporting Information [Line Items]
Revenue	(9)		(10)		(34)		(33)
Operating Income (Loss)	(46)		(51)		(138)		(147)
Intersegment Eliminations | Risk and Insurance Services Segment
Segment Reporting Information [Line Items]
Revenue	1		1		5		5
Intersegment Eliminations | Consulting Segment
Segment Reporting Information [Line Items]
Revenue	$ 8		$ 9		$ 29		$ 28

[1] Includes inter-segment revenue of $1 million in both 2017 and 2016, interest income on fiduciary funds of $11 million and $8 million in 2017 and 2016, respectively, and equity method income of $2 million and $4 million in 2017 and 2016, respectively.

[2] Includes inter-segment revenue of $5 million in both 2017 and 2016, interest income on fiduciary funds of $28 million and $20 million in 2017 and 2016, respectively, and equity method income of $11 million in both 2017 and 2016.

[3] Includes inter-segment revenue of $8 million and $9 million in 2017 and 2016, respectively, interest income on fiduciary funds of $2 million in 2017 and $1 million in 2016, respectively, and equity method income of $3 million in 2017 and $5 million in 2016, respectively.

[4] Includes inter-segment revenue of $29 million and $28 million in 2017 and 2016, respectively, interest income on fiduciary funds of $3 million in 2017 and $2 million in 2016, respectively, and equity method income of $12 million in 2017 and $14 million in 2016, respectively.

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Segment Information (Details of Operating Segment Revenue) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 3,341		$ 3,135		$ 10,339		$ 9,847
Operating Segments
Segment Reporting Information [Line Items]
Revenue	3,350		3,145		10,373		9,880
Operating Segments | Risk and Insurance Services Segment
Segment Reporting Information [Line Items]
Revenue	1,763	[1]	1,632	[1]	5,668	[2]	5,350	[2]
Operating Segments | Risk and Insurance Services Segment | Marsh Insurance Group
Segment Reporting Information [Line Items]
Revenue	1,490		1,370		4,713		4,427
Operating Segments | Risk and Insurance Services Segment | Guy Carpenter Reinsurance Group
Segment Reporting Information [Line Items]
Revenue	273		262		955		923
Operating Segments | Consulting Segment
Segment Reporting Information [Line Items]
Revenue	1,587	[3]	1,513	[3]	4,705	[4]	4,530	[4]
Operating Segments | Consulting Segment | Mercer Consulting Group
Segment Reporting Information [Line Items]
Revenue	1,149		1,109		3,335		3,227
Operating Segments | Consulting Segment | Oliver Wyman Group Consulting Group
Segment Reporting Information [Line Items]
Revenue	438		404		1,370		1,303
Corporate and Eliminations
Segment Reporting Information [Line Items]
Revenue	$ (9)		$ (10)		$ (34)		$ (33)

[1] Includes inter-segment revenue of $1 million in both 2017 and 2016, interest income on fiduciary funds of $11 million and $8 million in 2017 and 2016, respectively, and equity method income of $2 million and $4 million in 2017 and 2016, respectively.

[2] Includes inter-segment revenue of $5 million in both 2017 and 2016, interest income on fiduciary funds of $28 million and $20 million in 2017 and 2016, respectively, and equity method income of $11 million in both 2017 and 2016.

[3] Includes inter-segment revenue of $8 million and $9 million in 2017 and 2016, respectively, interest income on fiduciary funds of $2 million in 2017 and $1 million in 2016, respectively, and equity method income of $3 million in 2017 and $5 million in 2016, respectively.

[4] Includes inter-segment revenue of $29 million and $28 million in 2017 and 2016, respectively, interest income on fiduciary funds of $3 million in 2017 and $2 million in 2016, respectively, and equity method income of $12 million in 2017 and $14 million in 2016, respectively.

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New Accounting Guidance - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount	$ 58
Adjustments to additional paid in capital, income tax benefit from share-based compensation		$ 30