Moody's (MCO) 10-Q 31 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information shares in Millions	9 Months Ended
	Sep. 30, 2018shares
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	MCO
Entity Registrant Name	MOODYS CORP /DE/
Entity Central Index Key	1,059,556
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding	191.6

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED)
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
Expenses
Operating	306.3	315.6	941.4	875.7
Selling, general and administrative	260.3	245.7	801.9	682.5
Depreciation and amortization	46.1	43	143.6	108.4
Acquisition-Related Expenses	1.3	10.1	4.1	16.7
Total expenses	614	614.4	1,891	1,683.3
Operating Income	466.8	448.5	1,491.6	1,355.3
Non-operating (expense) income, net
Interest expense, net	(56.4)	(53.1)	(160.5)	(150.2)
Other non-operating income, net	2.4	0.5	18.3	3.2
Purchase price hedge gain		69.9		111.1
CCXI gains				59.7
Total non-operating (expense) income, net	(54)	17.3	(142.2)	23.8
Income before provisions for income taxes	412.8	465.8	1,349.4	1,379.1
Provision for income taxes	100.8	146.1	282.7	399.9
Net income	312	319.7	1,066.7	979.2
Less: Net income attributable to noncontrolling interests	1.8	2.4	7.4	4.1
Net income attributable to Moody's	$ 310.2	$ 317.3	$ 1,059.3	$ 975.1
Earnings per share attributable to Moody's common shareholders
Basic	$ 1.62	$ 1.66	$ 5.53	$ 5.1
Diluted	$ 1.59	$ 1.63	$ 5.45	$ 5.02
Weighted average number of shares outstanding
Basic	191.8	191.1	191.7	191.1
Diluted	194.5	194.1	194.4	194.1
Dividends declared per share attributable to Moody's common shareholders	$ 0.44	$ 0.38	$ 1.32	$ 0.76

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments Gain Loss [Line Items]
Net income	$ 312	$ 319.7	$ 1,066.7	$ 979.2
Foreign currency translation:
Foreign currency translation adjustments - Pre Tax	(46.5)	45.4	(175.2)	94.9
Foreign currency translation adjustment - Tax	(1.8)	6.4	(7.4)	19.5
Foreign currency translation adjustments - Net of Tax	(48.3)	51.8	(182.6)	114.4
Cash flow hedges:
Net realized and unrealized gain (loss) on cash flow hedges - Net of Tax	4	(6.7)	22	(24)
Reclassification of losses included in net income - Pre Tax	(0.1)	(4.2)	(0.3)	(11.7)
Reclassification of losses included in net income - Tax Amount		1.6		4.9
Reclassification of losses included in net income- Net of Tax	(0.1)	(2.6)	(0.3)	(6.8)
Available for sale securities:
Net unrealized gains on available for sale securities - Pre Tax		0.5		1.6
Net unrealized gains on available for sale securities - Net of Tax		0.5		1.6
Reclassification of gains included in net income - Pre Tax		(2.2)		(2.2)
Reclassification of gains included in net income - Net of Tax		(2.2)		(2.2)
Pension and Other Retirement Benefits:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	1.1	2.1	3.5	6.4
Amortization of actuarial losses and prior service costs included in net income - Tax	(0.3)	(0.8)	(1)	(2.5)
Amortization of actuarial losses and prior service costs included in net income - Net of Tax	0.8	1.3	2.5	3.9
Net actuarial losses and prior service costs - Pre Tax			1.6	7.9
Net actuarial losses and prior service costs - Tax			(0.4)	(3)
Net actuarial losses and prior service costs - Net of Tax			1.2	4.9
Total other comprehensive (loss) income - Pre Tax	(45.5)	46.8	(168.5)	106.9
Total other comprehensive (loss)income - Tax	(2.1)	5.2	(9.2)	15.1
Total other comprehensive (loss) income - Net of Tax	(47.6)	52	(177.7)	122
Comprehensive income	264.4	371.7	889	1,101.2
Less: Comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interest	(8.4)	3.1	(2.7)	19.6
Comprehensive income attributable to Moody's	272.8	368.6	891.7	1,081.6
Cash Flow Hedging [Member]
Cash flow hedges:
Net realized and unrealized gain (loss) on cash flow hedges - Pre Tax		5.2	1.9	10
Net realized and unrealized gain (loss) on cash flow hedges - Tax Amount		(2)	(0.4)	(3.8)
Net realized and unrealized gain (loss) on cash flow hedges - Net of Tax		3.2	1.5	6.2
Reclassification of losses included in net income- Net of Tax	$ (0.1)	$ (2.6)	$ (0.3)	$ (6.8)

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,034.8	$ 1,071.5
Short-term investments	110.7	111.8
Accounts receivable, net of allowances of $36.9 in 2018 and $36.6 in 2017	1,131.8	1,147.2
Other current assets	238.9	250.1
Total current assets	2,516.2	2,580.6
Property and equipment, net of accumulated depreciation of $767.9 in 2018 and $706.0 in 2017	311.1	325.1
Goodwill	3,661.3	3,753.2
Intangible assets, net	1,517.6	1,631.6
Deferred tax assets, net	189.3	143.8
Other assets	243.6	159.9
Total assets	8,439.1	8,594.2
Current liabilities:
Accounts payable and accrued liabilities	581.6	750.3
Commercial paper	24.9	129.9
Current portion of long-term debt	445.6	299.5
Deferred revenue	771.5	883.6
Total current liabilities	1,823.6	2,063.3
Non-current portion of deferred revenue	123.9	140
Long-term debt	4,484	5,111.1
Deferred tax liabilities, net	354.8	341.6
Unrecognized tax benefits	471.8	389.1
Other liabilities	574.9	664
Total liabilities	7,833	8,709.1
Contingencies (Note 14)
Shareholders' (deficit) equity
Preferred stock, par value $.01 per share; 10,000,000 shares authorized; no shares issued and outstanding
Common stock	3.4	3.4
Capital surplus	569.7	528.6
Retained earnings	8,429.1	7,465.4
Treasury stock, at cost; 151,293,579 and 151,932,157 shares of common stock at September 30, 2018 and December 31, 2017, respectively	(8,260.1)	(8,152.9)
Accumulated other comprehensive loss	(342)	(172.2)
Total Moody's shareholders' deficit	400.1	(327.7)
Noncontrolling interests	206	212.8
Total shareholders' deficit	606.1	(114.9)
Total liabilities and shareholders' (deficit) equity	8,439.1	8,594.2
Series common stock
Shareholders' (deficit) equity
Common stock

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable, allowances	$ 36.9	$ 36.6
Property and equipment, accumulated depreciation	$ 767.9	$ 706
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	342,902,272	342,902,272
Treasury stock, shares	151,293,579	151,932,157
Series common stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	10,000,000	10,000,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 1,066.7	$ 979.2
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization	143.6	108.4
Stock-based compensation expense	100	88.9
CCXI gains		(59.7)
Purchase price hedge gain		(111.1)
Deferred income taxes	(75.3)	161.4
Changes in assets and liabilities:
Accounts receivable	22.5	(9.8)
Other current assets	36.6	(16.2)
Other assets	(7.4)	11.4
Accounts payable and accrued liabilities	(176.5)	(827.2)
Deferred revenue	(35.3)	(19.3)
Unrecognized tax benefits and other non-current tax liabilities	42.8	18.4
Other liabilities	(33.1)	25.4
Net cash provided by (used in) operating activities	1,084.6	349.8
Cash flows from investing activities
Capital additions	(62.9)	(69.4)
Purchases of investments	(142.5)	(124)
Sales and maturities of short-term investments	120.9	183.8
Cash received upon diposal of a subsidiary, net of cash transferred to purchaser	5.7
Cash paid for acquisitions, net of cash acquired and equity investments	(35)	(3,511)
Receipts from purchase price hedge		111.1
Receipts from settlements of net investment hedges		2.1
Net cash used in investing activities	(113.8)	(3,407.4)
Cash flows from financing activities
Issuance of notes	299.6	2,291.9
Repayments of notes	(750)	(300)
Issuance of commercial paper	434.4	1,437.5
Repayments of commercial paper	(539.2)	(1,123.2)
Proceeds from stock-based compensation plans	42.9	49.3
Repurchase of shares related to stock-based compensation	(62)	(48.3)
Cost of treasury shares repurchased	(147.2)	(163.6)
Dividends	(252.9)	(217.8)
Dividends to noncontrolling interests	(4)	(3.2)
Payment for noncontrolling interest		(6.2)
Debt issuance costs, extinguishment costs and related fees	(1.8)	(26.8)
Net cash provided (used in) by financing activities	(980.2)	1,889.6
Effect of exchange rate changes on cash and cash equivalents	(27.3)	79.3
Net increase (decrease) in cash and cash equivalents	(36.7)	(1,088.7)
Cash and cash equivalents, beginning of the period	1,071.5	2,051.5
Cash and cash equivalents, end of the period	$ 1,034.8	$ 962.8

GLOSSARY OF TERMS AND ABBREVIAT

GLOSSARY OF TERMS AND ABBREVIATIONS	9 Months Ended
	Sep. 30, 2018
Glossary of Terms and Abbreviations [Abstract]
GLOSSARY OF TERMS AND ABBREVIATIONS	GLOSSARY OF TERMS AND ABBREVIATIONS The following terms, abbreviations and acronyms are used to identify frequently used terms in this report: TERM DEFINITION Acquisition-Related Amortization Amortization of definite-lived intangible assets acquired by the Company from all business combination transactions Acquisition-Related Expenses Consists of expenses incurred to complete and integrate the acquisition of Bureau van Dijk for which the integration will be a multi-year effort Adjusted Diluted EPS Diluted EPS excluding the impact of certain items as detailed in the section entitled “Non-GAAP Financial Measures” Adjusted Net Income Net Income excluding the impact of certain items as detailed in the section entitled “Non-GAAP Financial Measures” Adjusted Operating Income Operating income excluding depreciation and amortization Adjusted Operating Margin Adjusted Operating Income divided by revenue Americas Represents countries within North and South America, excluding the U.S. AOCI Accumulated other comprehensive income (loss); a separate component of shareholders’ equity (deficit) ASC The FASB Accounting Standards Codification; the sole source of authoritative GAAP as of July 1, 2009 except for rules and interpretive releases of the SEC, which are also sources of authoritative GAAP for SEC registrants ASC 605 The U.S. GAAP authoritative guidance for revenue accounting prior to the adoption of ASU No. 2014-09, “Revenue from Contracts with Customers (ASC Topic 606). Asia-Pacific Represents Australia and countries in Asia including but not limited to: China, India, Indonesia, Japan, Korea, Malaysia, Singapore, Sri Lanka and Thailand ASU The FASB Accounting Standards Update to the ASC. It also provides background information for accounting guidance and the bases for conclusions on the changes in the ASC. ASUs are not considered authoritative until codified into the ASC Board The board of directors of the Company BPS Basis points Bureau van Dijk Bureau van Dijk Electronic Publishing, B.V., a global provider of business intelligence and company information; acquired by the Company on August 10, 2017 via the acquisition of Yellow Maple I B.V., an indirect parent of Bureau van Dijk. CCXI China Cheng Xin International Credit Rating Co. Ltd.; China’s first and largest domestic credit rating agency approved by the People's Bank of China; the Company acquired a 49% interest in 2006; currently Moody’s owns 30% of CCXI. CCXI Gain In the first quarter of 2017 CCXI, as part of a strategic business realignment, issued additional capital to its majority shareholder in exchange for a ratings business wholly-owned by the majority shareholder and which has the right to rate a different class of debt instrument in the Chinese market. The capital issuance by CCXI in exchange for this ratings business diluted Moody’s ownership interest in CCXI to 30% of a larger business and resulted in a $59.7 million non-cash, non-taxable gain. CFG Corporate finance group; an LOB of MIS CLO Collateralized loan obligation CMBS Commercial mortgage-backed securities; part of the CREF asset class within SFG Commission European Commission Common Stock The Company’s common stock Company Moody’s Corporation and its subsidiaries; MCO; Moody’s Council Council of the European Union CP Commercial Paper CP Notes Unsecured commercial paper issued under the CP Program CP Program A program entered into on August 3, 2016 allowing the Company to privately place CP up to a maximum of $1 billion for which the maturity may not exceed 397 days from the date of issue and which is backstopped by the 2015 facility. CRAs Credit rating agencies CRA3 Regulation (EU) No 462/2013 of the European Parliament and of the Council, which updated the regulatory regimes imposing additional procedural requirements on CRAs CREF Commercial real estate finance which includes REITs, commercial real estate CDOs and mortgage-backed securities; part of SFG D&A Depreciation and amortization DBPPs Defined benefit pension plans Debt/EBITDA Ratio of Total Debt to EBITDA EBITDA Earnings before interest, taxes, depreciation and amortization EMEA Represents countries within Europe, the Middle East and Africa EPS Earnings per share ERS The Enterprise Risk Solutions LOB within MA, which offers risk management software solutions as well as related risk management advisory engagements services ESA Economics and Structured Analytics; part of the RD&A line of business within MA ESMA European Securities and Markets Authority ETR Effective tax rate EU European Union EUR Euros EURIBOR The Euro Interbank Offered Rate Excess Tax Benefits The difference between the tax benefit realized at exercise of an option or delivery of a restricted share and the tax benefit recorded at the time the option or restricted share is expensed under GAAP Exchange Act The Securities Exchange Act of 1934, as amended FASB Financial Accounting Standards Board FIG Financial institutions group; an LOB of MIS Financial Reform Act Dodd-Frank Wall Street Reform and Consumer Protection Act Free Cash Flow Net cash provided by operating activities less cash paid for capital additions FSTC Financial Services Training and Certifications; part of the PS LOB and a reporting unit within the MA reportable segment; consists of on-line and classroom-based training services and CSI Global Education, Inc. FX Foreign exchange GAAP U.S. Generally Accepted Accounting Principles GBP British pounds ICRA ICRA Limited; a leading provider of credit ratings and research in India. The Company previously held 28.5% equity ownership and in June 2014, increased that ownership stake to just over 50% through the acquisition of additional shares IASB International Accounting Standards Board IFRS International Financial Reporting Standards IRS Internal Revenue Service IT Information technology KIS Korea Investors Service, Inc; a leading Korean rating agency and consolidated subsidiary of the Company KIS Pricing Korea Investors Service Pricing, Inc; a leading Korean provider of fixed income securities pricing and consolidated subsidiary of the Company KIS Research Korea Investors Service Research; a Korean provider of financial research and consolidated subsidiary of the Company Korea Republic of South Korea LIBOR London Interbank Offered Rate LOB Line of business M&A Mergers and acquisitions MA Moody’s Analytics – a reportable segment of MCO which provides a wide range of products and services that support financial analysis and risk management activities of institutional participants in global financial markets; consists of three LOBs – RD&A, ERS and PS Make Whole Amount The prepayment penalty amount relating to the Series 2007-1 Notes, 2010 Senior Notes, 2012 Senior Notes, 2013 Senior Notes, 2014 Senior Notes (5-year), 2014 Senior Notes (30-year), 2015 Senior Notes, 2017 Senior Notes and 2018 Senior Notes which is a premium based on the excess, if any, of the discounted value of the remaining scheduled payments over the prepaid principal MAKS Moody’s Analytics Knowledge Services; formerly known as Copal Amba; provides offshore research and analytic services to the global financial and corporate sectors; part of the PS LOB and a reporting unit within the MA reportable segment MALS Moody’s Analytics Learning Solutions; a reporting unit within the MA segment that includes on-line and classroom-based training services as well as credentialing and certification services; formerly known as FSTC MCO Moody’s Corporation and its subsidiaries; the Company; Moody’s MD&A Management’s Discussion and Analysis of Financial Condition and Results of Operations MIS Moody’s Investors Service – a reportable segment of MCO; consists of five LOBs – SFG, CFG, FIG, PPIF and MIS Other MIS Other Consists of non-ratings revenue from ICRA, KIS Pricing and KIS Research. These businesses are components of MIS; MIS Other is an LOB of MIS Moody’s Moody’s Corporation and its subsidiaries; MCO; the Company Net Income Net income attributable to Moody’s Corporation, which excludes net income from consolidated noncontrolling interests belonging to the minority interest holder New Revenue Accounting Standard Updates to the ASC pursuant to ASU No. 2014-09, “Revenue from Contracts with Customers (ASC Topic 606)”. This new accounting guidance significantly changes the accounting framework under U.S. GAAP relating to revenue recognition and to the accounting for the deferral of incremental costs of obtaining or fulfilling a contract with a customer NM Percentage change is not meaningful Non-GAAP A financial measure not in accordance with GAAP; these measures, when read in conjunction with the Company’s reported results, can provide useful supplemental information for investors analyzing period-to-period comparisons of the Company’s performance, facilitate comparisons to competitors’ operating results and to provide greater transparency to investors of supplemental information used by management in its financial and operational decision making NRSRO Nationally Recognized Statistical Rating Organization, which is a credit rating agency registered with the SEC. OCI Other comprehensive income (loss); includes gains and losses on cash flow and net investment hedges, unrealized gains and losses on available for sale securities (in periods prior to January 1, 2018), certain gains and losses relating to pension and other retirement benefit obligations and foreign currency translation adjustments Omega Performance A leading provider of online credit training, which serves more than 300 customers, ranging from large global banks to local lending institutions; acquired by the Company in August 2018 Operating segment Term defined in the ASC relating to segment reporting; the ASC defines an operating segment as a component of a business entity that has each of the three following characteristics: i) the component engages in business activities from which it may recognize revenue and incur expenses; ii) the operating results of the component are regularly reviewed by the entity’s chief operating decision maker; and iii) discrete financial information about the component is available. Other Retirement Plan The U.S. retirement healthcare and U.S. retirement life insurance plans PCS Post-Contract Customer Support PPIF Public, project and infrastructure finance; an LOB of MIS Profit Participation Plan Defined contribution profit participation plan that covers substantially all U.S. employees of the Company PS Professional Services, an LOB within MA consisting of MAKS and FSTC that provides research and analytical services as well as financial training and certification programs Purchase Price Hedge Foreign currency collars and forward contracts entered into by the Company to economically hedge the Bureau van Dijk euro denominated purchase price Purchase Price Hedge Gain Gain on foreign currency collars to economically hedge the Bureau van Dijk euro denominated purchase price RD&A an LOB within MA that offers subscription based research, data and analytical products, including credit ratings produced by MIS, credit research, quantitative credit scores and other analytical tools, economic research and forecasts, business intelligence and company information products, and commercial real estate data and analytical tools. Reform Act Credit Rating Agency Reform Act of 2006 REIT Real Estate Investment Trust Relationship Revenue For MIS, represents recurring monitoring fees of a rated debt obligation and/or entities that issue such obligations, as well as revenue from programs such as commercial paper, medium-term notes and shelf registrations. For MIS Other represents subscription-based revenue. For MA, represents subscription-based revenue and software maintenance revenue Retirement Plans Moody’s funded and unfunded pension plans, the healthcare plans and life insurance plans SaaS Software-as-a-Service SCDM SCDM Financial, a leading provider of analytical tools for participants in securitization markets. Moody’s acquired SCDM’s structured finance data and analytics business in February 2017 SEC U.S. Securities and Exchange Commission Securities Act Securities Act of 1933, as amended Series 2007-1 Notes Principal amount of $300 million, 6.06% senior unsecured notes due in September 2017 pursuant to the 2007 Agreement; prepaid in March 2017 Settlement Charge Charge of $863.8 million recorded in the fourth quarter of 2016 related to an agreement entered into on January 13, 2017 with the U.S. Department of Justice and the attorneys general of 21 U.S. states and the District of Columbia to resolve pending and potential civil claims related to credit ratings that MIS assigned to certain structured finance instruments in the financial crisis era SFG Structured finance group; an LOB of MIS SG&A Selling, general and administrative expenses SSP Standalone selling price T&M Time-and-Material Tax Act The “Tax Cuts and Jobs Act” enacted into U.S. law on December 22, 2017 which significantly amends the tax code in the U.S. Total Debt All indebtedness of the Company as reflected on the consolidated balance sheets Transaction Revenue For MIS, represents the initial rating of a new debt issuance as well as other one-time fees. For MIS Other, represents revenue from professional services as well as data services, research and analytical engagements. For MA, represents perpetual software license fees and revenue from software implementation services, risk management advisory projects, training and certification services, and research and analytical engagements U.K. United Kingdom U.S. United States USD U.S. dollar UTPs Uncertain tax positions VSOE Vendor specific objective evidence; as defined in the ASC, evidence of selling price limited to either of the following: the price charged for a deliverable when it is sold separately, or for a deliverable not yet being sold separately, the price established by management having the relevant authority 2007 Agreement Note purchase agreement dated September 7, 2007, relating to the Series 2007-1 Notes 2010 Indenture Supplemental indenture and related agreements dated August 19, 2010, relating to the 2010 Senior Notes 2010 Senior Notes Principal amount of $500 million, 5.50% senior unsecured notes due in September 2020 pursuant to the 2010 Indenture 2012 Indenture Supplemental indenture and related agreements dated August 18, 2012, relating to the 2012 Senior Notes 2012 Senior Notes Principal amount of $500 million, 4.50% senior unsecured notes due in September 2022 pursuant to the 2012 Indenture 2013 Indenture Supplemental indenture and related agreements dated August 12, 2013, relating to the 2013 Senior Notes 2013 Senior Notes Principal amount of the $500 million, 4.875% senior unsecured notes due in February 2024 pursuant to the 2013 Indenture 2014 Indenture Supplemental indenture and related agreements dated July 16, 2014, relating to the 2014 Senior Notes 2014 Senior Notes (5-Year) Principal amount of $450 million, 2.75% senior unsecured notes due in July 2019 2014 Senior Notes (30-Year) Principal amount of $600 million, 5.25% senior unsecured notes due in July 2044 2015 Facility Five-year unsecured revolving credit facility, with capacity to borrow up to $1 billion; backstops CP issued under the CP Program 2015 Indenture Supplemental indenture and related agreements dated March 9, 2015, relating to the 2015 Senior Notes 2015 Senior Notes Principal amount of €500 million, 1.75% senior unsecured notes issued March 9, 2015 and due in March 2027 2017 Floating Rate Senior Notes Principal amount of $300 million, floating rate senior unsecured notes due in September 2018 2017 Indenture Collectively the Supplemental indenture and related agreements dated March 2, 2017, relating to the 2017 Floating Rate Senior Notes and 2017 Notes Due 2023 and 2028, and the supplemental indenture and related agreements dated June 12, 2017, relating to the 2017 Notes Due 2023 and 2028 2017 Senior Notes Due 2023 Principal amount of $500 million, 2.625% senior unsecured notes due January 15, 2023 2017 Senior Notes Due 2028 Principal amount of $500 million, 3.250% senior unsecured notes due January 15, 2028 2017 Senior Notes Due 2021 Principal amount of $500 million, 2.75% senior unsecured notes due in December 2021 2017 Term Loan $500 million, three-year term loan facility entered into on June 6, 2017 for which the Company drew down $500 million on August 8, 2017 to fund the acquisition of Bureau van Dijk 2018 Senior Notes Principal amount of $300 million, 3.250% senior unsecured notes due June 7, 2021

DESCRIPTION OF BUSINESS AND BAS

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2018
Description of Business and Basis of Presentation [Abstract]
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	NOTE 1 . DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Moody’s is a provider of (i) credit ratings; (ii) credit, capital markets and economic research, data and analytical tools; (iii) software solutions that support financial risk management activities; (iv) quantitatively derived credit scores; (v) learning solutions and certification services ; (vi) offshore financial research and analytical services; and (vii) company information and business intelligence products. Moody’s reports in two reportable segments: MIS and MA. MIS, the credit rating agency, publishes credit ratings on a wide range of debt obligations and the entities that issue such obligations in markets worldwide. Revenue is primarily derived from the originators and issuers of such transactions who use MIS ratings in the distribution of their debt issues to investors. Additionally, MIS earns revenue from certain non-ratings-related operations which consist primarily of financial instrument pricing services in the Asia-Pacific region as well as revenue from ICRA’s non-ratings operations. The revenue from these operations is included in the MIS Other LOB and is not material to the results of the MIS segment. The MA segment develops a wide range of products and services that support financial analysis and risk management activities of institutional participants in global financial markets. Within its RD&A business, MA offers subscription based research, data and analytical products, inclu ding credit ratings produced by MIS, credit research, quantitative credit scores and other analytical tools, economic research and forecasts, business intelligence and company information products, and commercial real estate data and analytical tools. Within its ERS business, MA provides software solutions as well as related risk management services. The PS business provides offshore analytical and research services along with learning solutions and certification programs. These interim financial statements have been prepared in accordance with the instructions to Form 10-Q and should be read i n conjunction with the Company’s consolidated financial statements and related notes in the Company’s 2017 annual report on Form 10-K filed with the SEC on February 27, 2018 . The results of interim periods are not necessarily indicative of results for the full year or any subsequent period. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for a fair presentation of financial position, results of operations and cash flows at the dates and for th e periods presented have been included. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. C ertain reclassifications have been made to prior period amounts to conform to the current presentation. Adoption of New Accounting Standard s On January 1, 2018, the Company adopted ASU No. 2014-09, “Revenue from Contracts with Customers (ASC Topic 606)” using the modified retrospective approach which Moody’s has elected to apply only to those contracts which were not completed as of January 1, 2018. Additionally, the Company has not retrospectively restated contract positions for contract modifica tions made prior to the adoption. ASU No. 2014-09 also includes updates related to the accounting for the deferral of incremental costs of obtaining or fulfilling a contract with a customer (“ASC Subtopic 340-40”). Hereunder, discussion of the provisions o f ASC Topic 606 and ASC Subtopic 340-40 are both individually and collectively referred to as the “New Revenue Accounting Standard.” Results for reporting periods beginning on January 1, 2018 are presented under the guidance set forth in the New Revenue Ac counting Standard, while prior period amounts have not been adjusted and continue to be reported in accordance with the previous accounting guidance. The most significant impacts to the Company’s financial statements from adopting the New Revenue Accounti ng Standard are primarily related to: i) the accounting for certain installed software subscription revenue in MA whereby the license rights within the arrangement are recognized at the inception of the contract based on SSP with the remainder recognized o ver the subscription period (compared to ASC Topic 605 whereby all installed software subscription revenue was previously recognized over the subscription period); ii) the accounting for certain ERS and ESA revenue arrangements where VSOE was not available under ASC Topic 605 now results in the acceleration of revenue recognition (compared to ASC Topic 605 whereby revenue was deferred due to lack of VSOE until all elements without VSOE had been delivered); iii) sales commissions incurred in the MA segment w ill be capitaliz ed and amortized over an extended period which is generally based upon the average economic life of products/services sold and incorporates anticipated subscription renewals ( compared to previous accounting guidance whereby capitalized sale s commissions were amortized over the committed subscription period only ); iv) the immediate expensing of software implementation project costs to fulfill a contract for its ERS and ESA businesses which under previous accounting guidance were capitalized a nd expensed when related project revenue was recognized; v) the capitalization of work-in-process costs for in-progress MIS ratings at the end of each reporting period which under ASC Topic 605 were expensed as incurred ; vi ) the timing of when revenue for certain MIS ratings products is recognized; and vii) the estimation of variable consideration at contract inception whereas under ASC Topic 605 companies were not required to consider the amount of consideration for which it expect ed to be entitled . The Company does not anticipate that applying the provisions of the N ew Revenue Accounting S tandard will have a material impact to its 2018 consolidated Net Income. However, there could be quarterly fluctuations in the financial results of both MIS and MA, or there could be increases or decreases in revenues and expenses which would largely offset and not be material to total consolidated Net Income for the full year. The table below provide s detail relating to the adjustment to the Company’s retained earnings balance upon adoption of the New Revenue Accounting Standard: Transition adjustment Benefit to / (reduction of) January 1, 2018 Retained Earnings Corresponding Balance Sheet Line Item Recognition of MA deferred revenue / increase in MA unbilled receivables (1) $108 million Deferred revenue, Non-current portion of deferred revenue, Accounts receivable, Other assets Increase to capitalized MA sales commissions (2) $78 million Other current assets, Other assets, Accounts payable and accrued liabilities Capitalization of work-in-process for in-progress ratings $9 million Other current assets Net impact of all other adjustments $4 million Various Net increase in tax liability on the above ($43 million) Deferred tax liabilities, net Total post-tax adjustment $156 million (1) Represents deferred revenue as of December 31, 2017 as well as amounts then unbilled that would have been recognized as revenue in 2017 or earlier if the New Revenue Accounting Standard was then in effect. These amounts will not be recognized as revenue in future statements of operations. Conversely, revenue will be recorded to the Company's statement of operations in 2018 under the New Revenue Accounting Standard, which otherwise would have been recognized in periods subsequent to 2018 if accounted for under ASC Topic 605. (2) Represents sales commissions that would have been capitalized as of December 31, 2017 if the New Revenue Accounting Standard was then in effect, but had previously been expensed by the Company under the previous accounting guidance. These sales commissions, as well as sales commissions incurred in 2018 related to new sales and renewals, will be amortized to expense in the statements of operations beginning in 2018 over an extended period generally based upon the average economic life of the products sold or over the period in which implementation and advisory services will be provided. The table below presents the cumulative effect of the changes made to the Company’s consolidated balance sheet at January 1, 2018 for the adoption of the New Revenue Accounting Standard : As Reported December 31, 2017 Adjustment Due to New Revenue Accounting Standard Balance at January 1, 2018 ASSETS Current assets: Cash and cash equivalents $ 1,071.5 $ - $ 1,071.5 Short-term investments 111.8 - 111.8 Accounts receivable, net of allowances 1,147.2 16.8 1,164.0 Other current assets 250.1 32.9 283.0 Total current assets 2,580.6 49.7 2,630.3 Property and equipment, net 325.1 - 325.1 Goodwill 3,753.2 - 3,753.2 Intangible assets, net 1,631.6 - 1,631.6 Deferred tax assets, net 143.8 - 143.8 Other assets 159.9 71.3 231.2 Total assets $ 8,594.2 $ 121.0 $ 8,715.2 LIABILITIES, NONCONTROLLING INTERESTS AND SHAREHOLDERS' (DEFICIT)/EQUITY Current liabilities: Accounts payable and accrued liabilities $ 750.3 $ (0.8) $ 749.5 Commercial paper 129.9 - 129.9 Current portion of long-term debt 299.5 - 299.5 Deferred revenue 883.6 (69.3) 814.3 Total current liabilities 2,063.3 (70.1) 1,993.2 Non-current portion of deferred revenue 140.0 (8.0) 132.0 Long-term debt 5,111.1 - 5,111.1 Deferred tax liabilities, net 341.6 42.7 384.3 Unrecognized tax benefits 389.1 - 389.1 Other liabilities 664.0 0.3 664.3 Total liabilities 8,709.1 (35.1) 8,674.0 Shareholders' (deficit) equity: Common stock 3.4 - 3.4 Capital surplus 528.6 - 528.6 Retained earnings 7,465.4 156.1 7,621.5 Treasury stock (8,152.9) - (8,152.9) Accumulated other comprehensive loss (172.2) - (172.2) Total Moody's shareholders' (deficit) equity (327.7) 156.1 (171.6) Noncontrolling interests 212.8 - 212.8 Total shareholders' (deficit) equity (114.9) 156.1 41.2 Total liabilities, noncontrolling interests and shareholders' (deficit) equity $ 8,594.2 $ 121.0 $ 8,715.2 The below table presents the impacts on the Company’s statement of operations for the current reporting period from applying the provisions of the New Revenue Accounting Standard compared to the accounting standard in effect before the change: For the Three Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) Revenue $ 1,080.8 $ 1,072.4 $ 8.4 Expenses Operating 306.3 306.6 (0.3) Selling, general and administrative 260.3 263.4 (3.1) Depreciation and amortization 46.1 46.1 - Acquisition-related expenses 1.3 1.3 - Total expenses 614.0 617.4 (3.4) Operating income 466.8 455.0 11.8 Non-operating (expense) income, net Interest expense, net (56.4) (56.4) - Other non-operating income, net 2.4 2.4 - Total non-operating (expense) income, net (54.0) (54.0) - Income before provision for income taxes 412.8 401.0 11.8 Provision for income taxes 100.8 98.4 2.4 Net income 312.0 302.6 9.4 Less: Net income attributable to noncontrolling interests 1.8 1.8 - Net income attributable to Moody's $ 310.2 $ 300.8 $ 9.4 Earnings per share Basic $ 1.62 $ 1.57 $ 0.05 Diluted $ 1.59 $ 1.55 $ 0.04 Weighted average shares outstanding Basic 191.8 191.8 Diluted 194.5 194.5 For the Nine Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) Revenue $ 3,382.6 $ 3,368.7 $ 13.9 Expenses Operating 941.4 942.8 (1.4) Selling, general and administrative 801.9 807.4 (5.5) Depreciation and amortization 143.6 143.6 - Acquisition-related expenses 4.1 4.1 - Total expenses 1,891.0 1,897.9 (6.9) Operating income 1,491.6 1,470.8 20.8 Non-operating (expense) income, net Interest expense, net (160.5) (160.5) - Other non-operating income, net 18.3 18.3 - Total non-operating (expense) income, net (142.2) (142.2) - Income before provision for income taxes 1,349.4 1,328.6 20.8 Provision for income taxes 282.7 277.6 5.1 Net income 1,066.7 1,051.0 15.7 Less: Net income attributable to noncontrolling interests 7.4 7.4 - Net income attributable to Moody's $ 1,059.3 $ 1,043.6 $ 15.7 Earnings per share Basic $ 5.53 $ 5.44 $ 0.09 Diluted $ 5.45 $ 5.37 $ 0.08 Weighted average shares outstanding Basic 191.7 191.7 Diluted 194.4 194.4 The below table presents the impacts on the Company’s consolidated balance sheet at the end of the current reporting period from applying the provisions of the New Revenue Accounting Standard compared to the accounting standard in effect before the change: As Reported September 30, 2018 Under previous accounting guidance September 30, 2018 Effect of Change Higher/(Lower) ASSETS Current assets: Cash and cash equivalents $ 1,034.8 $ 1,034.8 $ - Short-term investments 110.7 110.7 - Accounts receivable, net of allowances 1,131.8 1,093.4 38.4 Other current assets 238.9 222.5 16.4 Total current assets: 2,516.2 2,461.4 54.8 Property and equipment, net 311.1 311.1 - Goodwill 3,661.3 3,661.3 - Intangible assets, net 1,517.6 1,517.6 - Deferred tax assets, net 189.3 189.3 - Other assets 243.6 172.6 71.0 Total assets $ 8,439.1 $ 8,313.3 $ 125.8 LIABILITIES, NONCONTROLLING INTERESTS AND SHAREHOLDERS' EQUITY Accounts payable and accrued liabilities $ 581.6 $ 581.4 $ 0.2 Commercial paper 24.9 24.9 - Current portion of long-term debt 445.6 445.6 - Deferred revenue 771.5 836.5 (65.0) Total current liabilities 1,823.6 1,888.4 (64.8) Non-current portion of deferred revenue 123.9 130.1 (6.2) Long-term debt 4,484.0 4,484.0 - Deferred tax liabilities, net 354.8 330.8 24.0 Unrecognized tax benefits 471.8 471.8 - Other liabilities 574.9 574.8 0.1 Total liabilities 7,833.0 7,879.9 (46.9) Shareholders' equity: Common stock 3.4 3.4 - Capital surplus 569.7 569.7 - Retained earnings 8,429.1 8,256.4 172.7 Treasury stock (8,260.1) (8,260.1) - Accumulated other comprehensive loss (342.0) (342.0) - Total Moody's shareholders' equity 400.1 227.4 172.7 Noncontrolling interests 206.0 206.0 - Total shareholders' equity 606.1 433.4 172.7 Total liabilities, noncontrolling interests and shareholders' equity $ 8,439.1 $ 8,313.3 $ 125.8 The below table presents the impacts on various line items within the operating cash flow within the Company’s statement of cash flows for the current reporting period from applying the provisions of the New Revenue Accounting Standard compared to the accounting standard in effect before the change. For the Nine Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Cash flows from operating activities Net income $ 1,066.7 $ 1,051.0 $ 15.7 Reconciliation of net income to net cash provided by operating activities: Depreciation and amortization 143.6 143.6 - Stock-based compensation 100.0 100.0 - Deferred income taxes (75.3) (59.3) (16.0) Changes in assets and liabilities: Accounts receivable 22.5 44.1 (21.6) Other current assets 36.6 20.1 16.5 Other assets (7.4) (7.8) 0.4 Accounts payable and accrued liabilities (176.5) (178.4) 1.9 Deferred revenue (35.3) (41.4) 6.1 Unrecognized tax benefits and other non-current tax liabilities 42.8 42.8 - Other liabilities (33.1) (30.1) (3.0) Net cash provided by operating activities $ 1,084.6 $ 1,084.6 $ - The New Revenue Accounting Standard did not have any impact on individual line items within investing or financing cash flows in the Company’s consolidated statement of cash flows. In 2018, the adoption of the New Revenue Accounting Standard will likely result in higher cash taxes as the cumulative catch-up adjustment to retained earnings is taxable and there is expected to be acceleration of revenue recognition under the New Revenue Accounting Standard. On January 1, 2018, the Company adopted ASU No. 201 7-07, “Compensation—Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost”. As required by this ASU, the components of net periodic pension costs were disaggregated in the sta tement of operations on a retrospective basis. The Company has continued to reflect the service cost component in either Operating or SG&A expenses in Moody’s statement of operations. The other components of net benefit cost are presented within non-operat ing (expense) income, net, within the statement of operations. The adoption of this ASU has no impact on Net Income in the Company’s statements of operations. The impact to the Company’s statements of operations for the three and nine months ended September 30, 2018 and 2017 related to the adoption of this ASU are set forth in the table below: For the Three Months Ended September 30, 2018 For the Three Months Ended September 30, 2017 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) As Adjusted Under previous accounting guidance Effect of Change Higher/(Lower) Operating expenses $ 306.3 $ 307.5 $ (1.2) $ 315.6 $ 317.2 $ (1.6) Selling, general and administrative expenses 260.3 261.4 (1.1) 245.7 247.2 (1.5) Operating income 466.8 464.5 2.3 448.5 445.4 3.1 Interest expense, net (56.4) (51.5) (4.9) (53.1) (48.1) (5.0) Other non-operating income (expense), net 2.4 (0.2) 2.6 0.5 (1.4) 1.9 For the Nine Months Ended September 30, 2018 For the Nine Months Ended September 30, 2017 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) As Adjusted Under previous accounting guidance Effect of Change Higher/(Lower) Operating expenses $ 941.4 $ 944.9 $ (3.5) $ 875.7 $ 880.4 $ (4.7) Selling, general and administrative expenses 801.9 805.1 (3.2) 682.5 686.8 (4.3) Operating income 1,491.6 1,484.9 6.7 1,355.3 1,346.3 9.0 Interest expense, net (160.5) (146.0) (14.5) (150.2) (135.5) (14.7) Other non-operating income (expense), net 18.3 10.5 7.8 3.2 (2.5) 5.7 On January 1, 2018, the Company adopted ASU No. 2016-01 “Financial Instruments—Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2016-01”). The amendments in this ASU update various aspects of recognition, measurement, presentation and disclosures relating to financial instruments. Upon adoption, the Company recorded a $2.3 million cumulative adjustment to reclassify net unrealized gains on investments in equity securities previously classified as available-for-sale under the previous guidance from AOCI to retained earnings. Beginning in the first quarter of 2018, the Company will measure equity investments with readily determinable fair values (except those accounted for under the equity method, those that result in consolidation of the investee and certain other investments) at fair value and recognize any changes in fair value in net income. The adoption of this ASU did not have a material impact on the Company’s financial statements for the thre e and nine months ended September 30, 2018. In March 2018, the FASB issued ASU No. 2018-05, "Income Taxes (Topic 740) - Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118". This ASU adds SEC paragraphs to the codification pursuant to the SEC Staff Accounting Bulletin No. 118, which addresses the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to finalize the calculations for the 2017 income ta x effects of the Tax Act. This ASU provides entities with a one year measurement period from the December 22, 2017 enactment date, in order to complete the accounting for the effects of the Tax Act. The Company has recorded a provisional estimate for the t ransition tax relating to the Tax Act which is more fully described in Note 5. This provisional estimate may be impacted by a number of additional considerations, including but not limited to the issuance of regulations and the Company’s ongoing analysis o f the new law. On January 1, 2018, the Company adopted ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a Consensus of the Emerging Issues Task Force)” on a retrospective basis. This ASU redu ces diversity in practice in how certain transactions are reflected in the statement of cash flows. Pursuant to the adoption of this ASU, the Company reclassified $7.1 million in cash paid in the first nine months of 2017 relating to a Make-Whole provision upon the repayment of the Series 2007-1 Notes from cash flows used in operations to cash flows provided by financing activities. During the second quarter of 2018, the Company early adopted ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improv ements to Accounting for Hedging Activities”. This ASU fosters enhanced transparency relating to risk management activities and simplifies the application of hedge accounting in certain circumstances. The adoption of this ASU did not have an impact on the Company’s financial statements at the date of adoption. Refer to Note 9 for further discussion on the prospective impact of this ASU on the Company’s financial statements.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2018
Summary of Significant Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 2 . SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The Company adopted the New Revenue Accounting Standard on January 1, 2018 using the modified retrospective transition method. Below are the Company’s revised accounting policies reflecting the provisions of the New Revenue Accounting Standard ; ASU 2016-01 (as codified under ASC Topic 321) relating to the accounting for financial instruments; and the amendments to ASC Topic 815 as a result of the Company’s second quarter adoption of ASU 2017-12 r elating to derivative instruments and hedging activities. The Company’s adoption of these ASUs is further discussed in Note 1. All other significant accounting policies described in the Form 10-K for the year ended December 31, 2017 remain unchanged. Also refer to Note 3 of the condensed consolidated financial statements for certain quantitative disclosures relating to the Company’s revenue from contracts with customers. Revenue Recognition and Costs to Obtain or Fulfill a Contract with a Customer Revenue recognition: Revenue is recognized when control of promised goods or services is transferred to the customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. When contracts with c ustomers contain multiple performance obligations, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to each distinct performance obligation on a relative SSP basis. The Company determines the SSP by using the price charged for a deliverable when sold separately or uses management’s best estimate of SSP for goods or services not sold separately based on the maximum number of observable data points, including: internal factors rele vant to its pricing practices such as costs and margin objectives; standalone sales prices of similar products; percentage of the fee charged for a primary product or service relative to a related product or service; and customer segment and geography. Add itional consideration is also given to market conditions such as competitor pricing strategies and market trends. Sales, usage-based, value added and other taxes are excluded from revenues. MIS Revenue In the MIS segment, revenue arrangements are generally comprised of two distinct performance obligations, an initial rating and the related monitoring service. Revenue attributed to initial ratings of issued securities is generally recognized when the rating is delivered to the issuer. Revenue attributed to m onitoring of issuers or issued securities is recognized ratably over the period in which the monitoring is performed, generally one year. In the case of certain structured finance products, primarily CMBS, issuers can elect to pay all of the annual monitor ing fees upfront. These fees are deferred and recognized over the future monitoring periods based on the expected lives of the rated securities. MIS arrangements generally have standard contractual terms for which the stated payments are due at conclusion of the ratings process for initial ratings and either upfront or in arrears for monitoring services; and are signed by customers either on a per issue basis or at the beginning of the relationship with the customer. However, customer fee arrangements may b e adjusted for which the Company accounts for as variable consideration at inception using the expected value method based on analysis of similar contracts in the same line of business , which is constrained based on the Company’s assessment of the realizat ion of the adjustment amount. The Company allocates the transaction price within arrangements that include both the initial rating and the related monitoring service based upon the relative SSP of each service. The Company generally uses management’s best estimate based on observable pricing points in determining SSP for its initial ratings as the Company rarely provides initial ratings separately without providing related monitoring services. The SSP for monitoring fees in these arrangements are generally based upon directly observable selling prices where the monitoring service is sold separately. MA Revenue In the MA segment, products and services offered by the Company include hosted research and data subscriptions, installed software subscriptions, perp etual installed software licenses and related maintenance, or PCS, and professional services. Subscription and PCS contracts are generally invoiced in advance of the contractual coverage period, which is principally one year, but can range from 3-5 years; while perpetual software licenses are generally invoiced upon delivery and professional services are invoiced as those services are provided. Payment terms and conditions vary by contract type, but primarily include a requirement of payment within 30 to 60 days. Revenue from research, data and other hosted subscriptions is recognized ratably over the related subscription period. A large portion of these services are invoiced in the months of November, December and January. Revenue from the sale of a softwar e license, when considered distinct from the related software implementation services, is generally recognized at the time the product master or first copy is delivered or transferred to the customer. However, in instances where the software license (perpe tual or subscription) and related implementation services are considered to be one combined performance obligation, revenue is recognized on a percentage-of-completion basis (input method) as implementation services are performed over time, which is consis tent with the pattern of recognition for the software implementation services if considered to be a separate distinct performance obligation. The Company exercises judgment in determining the level of integration and interdependency between the promise to grant the software license and the promise to deliver the related implementation services. This determination influences whether the software license is considered distinct and accounted for separately, or not distinct and accounted for together with the i mplementation services and recognized over time. PCS is generally recognized ratably over the contractual period commencing when the software license is fully delivered. Revenue from installed software subscriptions, which includes PCS, is bifurcated into a software license performance obligation and a PCS performance obligation, which follow the patterns of recognition described above. For implementation services and other service projects within the ERS and ESA LOBs for which fees are fixed, the Company d etermined progress towards completion is most accurately measured on a percentage-of-completion basis (input method) as this approach utilizes the most directly observable data points and is therefore used to recognize the related revenue. For implementati on services where price varies based on time expended, a time-based measure of progress towards completion of the performance obligation is utilized. Revenue from professional services rendered within the PS LOB is generally recognized as the services are performed over time . Products and services offered within the MA segment are sold either stand-alone or together in various combinations. In instances where an arrangement contains multiple performance obligations, the Company accounts for the individual p erformance obligations separately if they are considered distinct. Revenue is generally allocated to all performance obligations based upon the relative SSP at contract inception. Judgment is often required to determine the SSP for each distinct performanc e obligation. Revenue is recognized for each performance obligation based upon the conditions for revenue recognition noted above. In the MA segment, customers usually pay a fixed fee for the products and services based on signed contracts. However, accounting for variable consideration is applied mainly for: i) estimates for cancellation rights and price concessions and ii) T&M based services. The Company estimates the variable consideration associated with cancellation rights and price concessions b ased on the expected amount to be provided to customers and reduces the amount of revenue to be recognized. T&M based contracts represent about half of MA’s service projects within the ERS and ESA LOBs. The Company provides agreed upon services at a contra cted daily or hourly rate. The commitment represents a series of goods and services that are substantially the same and have the same pattern of transfer to the customer. As such, if T&M services are sold with other MA products, the Company allocates the v ariable consideration entirely to the T&M performance obligation if the services are sold at standard pricing or at a similar discount level compared to other performance obligations in the same revenue contract. If these criteria are not met, the Company estimates variable consideration for each performance obligation upfront. Each form of variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal of any incremental revenue will not occur. Costs to Obtain or Fulfill a Contract with a Customer: Costs incurred to obtain customer contracts, such as sales commissions, are deferred and recorded within other current assets and other assets when such costs are determined to be incremental to obtaining a contract, would not have been incurred otherwise and the Company expects to recover those costs. These costs are amortized to expense consistent with the recognition pattern of the related revenue over time . Depending on the line of business to which the contract relates, this may be based upon the average economic life of the products sold or average period for which services are provided, inclusive of anticipated contract renewals. Determining the estimated economic life of the products sold r equires judgment with respect to anticipated future technological changes. The Company had a balance of $ 93.3 million in such deferred costs as of September 30, 2018 and recognized $ 8.0 million and $24.7 million of relat ed amortization during the three and nine -month period s ended September 30, 2018 , respectively, which is included within SG&A expenses in the consolidated statement of operations. Costs incurred to obtain customer contracts are only in the MA segment. Costs incurred to fulfill customer contracts, are deferred and recorded within other current assets and other assets when such costs relate directly to a contract , generate or enhance resources of the Company that will be used in satisfying performance obligations in the future an d the Company expects to recover those costs. The Company capitalizes work-in-process costs for in-progress MIS ratings, which is recognized consistent with the rendering of the related services to the customers, as ratings are issued. The Company had a ba lance of $10.6 million in such deferred costs as of September 30, 2018 and recognized $ 10.3 million and $29.8 million of amortization of the costs during the three and nine-month periods ended September 30, 2018, respectively, which is included within operating expenses in the consolidated statement of operations. In addition, within the MA segment, the Company capitalizes royalty costs related to third-party information data providers associated with hosted company information and business intelligence products. These costs are amortized to expense consistent with the recognition pattern of the related revenue over time. The Company had a balance of $ 24.8 million in such deferred costs as of September 30, 2018 and recognized $12.9 million and $41.2 million of relat ed a mortization during the three and nine -month period s ended September 30, 2018 , respectively, which is included within operating expenses in the consolidated statement of operations. Fair Value of Financial Instruments The Company’s financial instruments include cash, cash equivalents, trade receivables and payables, all of which are short-term in nature and, accordingly, approximate fair value. Additionally, the Company invests in certain short-term investments consisting primarily of certificates of depo sit that are carried at cost, which approximates fair value due to their short-term maturities. The Company also has certain investments in closed-ended and open-ended mutual funds in India which are accounted for as equity securities with readily determin able fair values under ASC Topic 321. Beginning in the first quarter of 2018, the Company will measure these investments at fair value with both realized gains and losses and unrealized holding gains and losses for these investments included in net income. Prior to January 1, 2018, the investments in closed-ended and open-ended mutual funds in India were designated as ‘available for sale’ under Topic 320 of the ASC. Accordingly, unrealized gains and losses on these investments were recorded to other compreh ensive income and were reclassified out of accumulated other comprehensive income to the statement of operations when the investment matured or was sold using a specific identification method. Also, the Company uses derivative instruments to manage certain financial exposures that occur in the normal course of business. These derivative instruments are carried at fair value on the Company’s consolidated balance sheets. Fair value is defined by the ASC as the price that would be received from selling an asse t or paid to transfer a liability (i.e., an exit price) in an orderly transaction between market participants at the measurement date. The determination of this fair value is based on the principal or most advantageous market in which the Company could com mence transactions and considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions and risk of nonperformance. Also, determination of fair value assumes that market participants will consider the highest and best use of the asset. The ASC establishes a fair value hierarchy whereby the inputs contained in valuation techniques used to measure fair value are categorized into three broad levels as follows: Level 1: quoted market pric es in active markets that the reporting entity has the ability to access at the date of the fair value measurement; Level 2: inputs other than quoted market prices described in Level 1 that are observable for the asset or liability, either directly or indi rectly, such as quoted prices in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active or other inputs that are observable or can be corroborated by observable market d ata for substantially the full term of the assets or liabilities; Level 3: unobservable inputs that are supported by little or no market activity and that are significant to the fair value measurement of the assets or liabilities. Derivative Instruments an d Hedging Activities Based on the Company’s risk management policy, from time to time the Company may use derivative financial instruments to reduce exposure to changes in foreign exchange rates and interest rates. The Company does not enter into derivati ve financial instruments for speculative purposes. All derivative financial instruments are recorded on the balance sheet at their respective fair values. The changes in the value of derivatives that qualify as fair value hedges are recorded in the same in come statement line item in earnings in which the corresponding adjustment to the carrying value of the hedged item is presented. The entire change in the fair value of derivatives that qualify as cash flow hedges is recorded to OCI and such amounts are re classified from AOCI to the same income statement line in earnings in the same period or periods during which the hedged transaction affects income. Effective with the Company early adoption of ASC 2017-12, the Company changed the method by which it assess es effectiveness for net investment hedges from the forward-method to the spot-method. The Company considers the spot-method an improved method of assessing hedge effectiveness, as spot rate changes relating to the hedging instrument’s notional amount per fectly offset the currency translation adjustment on the hedged net investment in the Company’s foreign subsidiaries. The entire change in the fair value of derivatives that qualify as net investment hedges is initially recorded to OCI. Those changes in fa ir value attributable to components included in the assessment of hedge effectiveness in a net investment hedge are recorded in the currency translation adjustment component of OCI and remain in AOCI until the period in which the hedged item affects earnin gs. Those changes in fair value attributable to components excluded from the assessment of hedge effectiveness in a net investment hedge are recorded to OCI and amortized to earnings using a systematic and rational method over the duration of the hedge. An y changes in the fair value of derivatives that the Company does not designate as hedging instruments under Topic 815 of the ASC are recorded in the consolidated statements of operations in the period in which they occur. Refer to Note 9 for further inform ation regarding the Company’s derivative financial instruments and hedging activities .

REVENUES

REVENUES	9 Months Ended
	Sep. 30, 2018
Revenues [Abstract]
REVENUES	NOTE 3 . REVENUES Revenue by Category The following table presents the Company’s revenues disaggregated by LOB: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 (1) 2018 2017 (1) MIS: Corporate finance (CFG) Investment-grade $ 51.0 $ 78.5 $ 199.4 $ 235.2 High-yield 38.3 62.9 154.8 189.8 Bank loans 75.9 82.4 301.9 274.1 Other accounts (2) 130.9 126.4 395.3 359.7 Total CFG 296.1 350.2 1,051.4 1,058.8 Structured finance (SFG) Asset-backed securities 24.6 22.8 80.7 69.6 Residential mortgage backed securities 23.7 21.9 74.8 64.7 Commercial real estate finance 25.9 37.5 90.7 96.7 Structured credit 50.7 45.6 148.6 115.2 Other accounts 0.5 0.5 1.9 1.5 Total SFG 125.4 128.3 396.7 347.7 Financial institutions (FIG) Banking 72.9 70.1 227.2 219.6 Insurance 37.7 23.9 98.9 72.4 Managed investments 5.5 4.6 18.4 15.6 Other accounts 3.4 3.5 9.9 9.2 Total FIG 119.5 102.1 354.4 316.8 Public, project and infrastructure finance (PPIF) Public finance / sovereign 45.3 49.4 143.9 155.6 Project and infrastructure 53.7 59.8 156.4 156.4 Total PPIF 99.0 109.2 300.3 312.0 Total ratings revenue 640.0 689.8 2,102.8 2,035.3 MIS Other 4.8 4.4 14.2 13.8 Total external revenue 644.8 694.2 2,117.0 2,049.1 Intersegment royalty 31.6 29.0 92.0 82.0 Total MIS 676.4 723.2 2,209.0 2,131.1 MA: Research, data and analytics (RD&A) 282.6 218.4 831.7 574.7 Enterprise risk solutions (ERS) 113.0 112.6 318.6 305.8 Professional services (PS) 40.4 37.7 115.3 109.0 Total external revenue 436.0 368.7 1,265.6 989.5 Intersegment revenue 2.6 4.1 10.0 11.6 Total MA 438.6 372.8 1,275.6 1,001.1 Eliminations (34.2) (33.1) (102.0) (93.6) Total MCO $ 1,080.8 $ 1,062.9 $ 3,382.6 $ 3,038.6 (1) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard. (2) Other includes: recurring monitoring fees of a rated debt obligation and/or entities that issue such obligations as well as fees from programs such as commercial paper, medium term notes, and ICRA corporate finance revenue. The following table presents the Company’s revenues disaggregated by LOB and geographic area: Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 (1) United States International Total United States International Total MIS: Corporate finance (CFG) $ 184.0 $ 112.1 $ 296.1 $ 234.0 $ 116.2 $ 350.2 Structured finance (SFG) 81.3 44.1 125.4 89.3 39.0 128.3 Financial institutions (FIG) 59.8 59.7 119.5 40.5 61.6 102.1 Public, project and infrastructure finance (PPIF) 59.4 39.6 99.0 63.8 45.4 109.2 Total ratings revenue 384.5 255.5 640.0 427.6 262.2 689.8 MIS Other 0.2 4.6 4.8 0.1 4.3 4.4 Total MIS 384.7 260.1 644.8 427.7 266.5 694.2 MA: Research, data and analytics (RD&A) 116.7 165.9 282.6 107.5 110.9 218.4 Enterprise risk solutions (ERS) 43.0 70.0 113.0 39.5 73.1 112.6 Professional services (PS) 15.2 25.2 40.4 13.7 24.0 37.7 Total MA 174.9 261.1 436.0 160.7 208.0 368.7 Total MCO $ 559.6 $ 521.2 $ 1,080.8 $ 588.4 $ 474.5 $ 1,062.9 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 (1) United States International Total United States International Total MIS: Corporate finance (CFG) $ 673.0 $ 378.4 $ 1,051.4 $ 698.6 $ 360.2 $ 1,058.8 Structured finance (SFG) 259.2 137.5 396.7 235.9 111.8 347.7 Financial institutions (FIG) 162.7 191.7 354.4 135.0 181.8 316.8 Public, project and infrastructure finance (PPIF) 173.9 126.4 300.3 192.8 119.2 312.0 Total ratings revenue 1,268.8 834.0 2,102.8 1,262.3 773.0 2,035.3 MIS Other 0.5 13.7 14.2 0.3 13.5 13.8 Total MIS 1,269.3 847.7 2,117.0 1,262.6 786.5 2,049.1 MA: Research, data and analytics (RD&A) 347.5 484.2 831.7 310.6 264.1 574.7 Enterprise risk solutions (ERS) 124.1 194.5 318.6 120.1 185.7 305.8 Professional services (PS) 41.8 73.5 115.3 40.7 68.3 109.0 Total MA 513.4 752.2 1,265.6 471.4 518.1 989.5 Total MCO $ 1,782.7 $ 1,599.9 $ 3,382.6 $ 1,734.0 $ 1,304.6 $ 3,038.6 (1) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard. The tables below summarize the split between transaction and relationship revenue. In the MIS segment, excluding MIS Other, transaction revenue represents the initial rating of a new debt issuance as well as other one-time fees while relationship revenue represents the recurring monitoring fees of a rated debt obligation and/or entities that issue such obligations, as well as revenue from programs such as commercial paper, medium-term notes and shelf registrations. In MIS Other, transaction revenue represe nts revenue from professional services and outsourcing engagements and relationship revenue represents subscription-based revenues. In the MA segment, relationship revenue represents subscription-based revenues and software maintenance revenue. Transaction revenue in MA represents perpetual software license fees and revenue from software implementation services, risk management advisory projects, training and certification services, and outsourced research and analytical engagements. Three Months Ended September 30, 2018 2017 (2) Transaction Relationship Total Transaction Relationship Total Corporate Finance $ 192.0 $ 104.1 $ 296.1 $ 254.3 $ 95.9 $ 350.2 65% 35% 100% 73% 27% 100% Structured Finance $ 81.0 $ 44.4 $ 125.4 $ 84.1 $ 44.2 $ 128.3 65% 35% 100% 66% 34% 100% Financial Institutions $ 56.2 $ 63.3 $ 119.5 $ 40.6 $ 61.5 $ 102.1 47% 53% 100% 40% 60% 100% Public, Project and Infrastructure Finance $ 60.8 $ 38.2 $ 99.0 $ 71.1 $ 38.1 $ 109.2 61% 39% 100% 65% 35% 100% MIS Other $ 0.5 $ 4.3 $ 4.8 $ 0.4 $ 4.0 $ 4.4 10% 90% 100% 9% 91% 100% Total MIS $ 390.5 $ 254.3 $ 644.8 $ 450.5 $ 243.7 $ 694.2 61% 39% 100% 65% 35% 100% Moody's Analytics $ 71.0 (1) $ 365.0 $ 436.0 $ 77.6 (1) $ 291.1 $ 368.7 16% 84% 100% 21% 79% 100% Total Moody's Corporation $ 461.5 $ 619.3 $ 1,080.8 $ 528.1 $ 534.8 $ 1,062.9 43% 57% 100% 50% 50% 100% Nine Months Ended September 30, 2018 2017 (2) Transaction Relationship Total Transaction Relationship Total Corporate Finance $ 741.2 $ 310.2 $ 1,051.4 $ 777.4 $ 281.4 $ 1,058.8 70% 30% 100% 73% 27% 100% Structured Finance $ 259.4 $ 137.3 $ 396.7 $ 216.8 $ 130.9 $ 347.7 65% 35% 100% 62% 38% 100% Financial Institutions $ 162.4 $ 192.0 $ 354.4 $ 137.9 $ 178.9 $ 316.8 46% 54% 100% 44% 56% 100% Public, Project and Infrastructure Finance $ 184.9 $ 115.4 $ 300.3 $ 197.5 $ 114.5 $ 312.0 62% 38% 100% 63% 37% 100% MIS Other $ 1.5 $ 12.7 $ 14.2 $ 1.0 $ 12.8 $ 13.8 11% 89% 100% 7% 93% 100% Total MIS $ 1,349.4 $ 767.6 $ 2,117.0 $ 1,330.6 $ 718.5 $ 2,049.1 64% 36% 100% 65% 35% 100% Moody's Analytics $ 198.3 (1) $ 1,067.3 $ 1,265.6 $ 205.0 $ 784.5 $ 989.5 16% 84% 100% 21% 79% 100% Total Moody's Corporation $ 1,547.7 $ 1,834.9 $ 3,382.6 $ 1,535.6 $ 1,503.0 $ 3,038.6 46% 54% 100% 51% 49% 100% (1) Revenue from software implementation services and risk management advisory projects, while classified by management as transactional revenue, is recognized over time under the New Revenue Accounting Standard (please also refer to the table below). (2) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard. The following table presents the timing of revenue recognition: Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 MIS MA Total MIS MA Total Revenue recognized at a point in time $ 390.5 $ 19.5 $ 410.0 $ 1,349.4 $ 49.0 $ 1,398.4 Revenue recognized over time 254.3 416.5 670.8 767.6 1,216.6 1,984.2 Total $ 644.8 $ 436.0 $ 1,080.8 $ 2,117.0 $ 1,265.6 $ 3,382.6 Unbilled receivables, Deferred revenue and Remaining performance obligations Unbilled receivables At September 30 , 2018, accounts receivable included approximately $ 349.4 million of unbilled receivables related to the MIS segment. Certain MIS arrangements contain contractual terms whereby the customers are billed in arrears for annual monitoring services , requiring revenue to be accrued as an unbilled receivable as such ser vices are provided . Additionally, there are other instances in which the timing of when the Company has the unconditional right to considerati on and recognizes revenue prior to invoicing the customer, for which an unbilled receivable is recorded. In addi tion, for certain MA arrangements, the timing of when the Company has the unconditional right to consideration and recognizes revenue occurs prior to invoicing the customer. Consequently, at September 30 , 2018, accounts receivable included approximately $ 5 7.0 million of unbilled receivables related to the MA segment. Historically, the Company has not had material differences between the estimated revenue and the actual billings. Deferred revenue The Company recognizes deferred revenue when a contract requires a customer to pay consideration to the Company in advance of when revenue related to that contract is recognized. This deferred revenue is relieved when the Company satisfies the related performance obligation and revenue is recognized. Significan t changes in the deferred revenue balances dur ing the three and nine months ended September 30 , 2018 are as follows: Three Months Ended September 30, 2018 MIS MA Total Balance at June 30, 2018 $ 377.5 $ 609.0 $ 986.5 Changes in deferred revenue Revenue recognized that was included in the deferred revenue balance at the beginning of the period (127.4) (241.8) (369.2) Increases due to amounts billable excluding amounts recognized as revenue during the period 101.6 176.6 278.2 Effect of exchange rate changes 1.1 (1.2) (0.1) Total changes in deferred revenue (24.7) (66.4) (91.1) Balance at September 30, 2018 $ 352.8 $ 542.6 $ 895.4 Nine Months Ended September 30, 2018 MIS MA Total Balance at January 1, 2018 (after New Revenue Accounting Standard transition adjustment) $ 334.7 $ 611.6 $ 946.3 Changes in deferred revenue Revenue recognized that was included in the deferred revenue balance at the beginning of the period (196.2) (417.1) (613.3) Increases due to amounts billable excluding amounts recognized as revenue during the period 217.6 359.9 577.5 Effect of exchange rate changes (3.3) (11.8) (15.1) Total changes in deferred revenue 18.1 (69.0) (50.9) Balance at September 30, 2018 $ 352.8 $ 542.6 $ 895.4 Deferred revenue - current $ 233.9 $ 537.6 $ 771.5 Deferred revenue - noncurrent $ 118.9 $ 5.0 $ 123.9 For the MIS segment, the changes in the deferred revenue balance during the three and nine months ended September 30, 2018 were primarily related to the significant portion of contract renewals that occur during the first quarter of 2018 and are generally recognized over a one year period. For the MA segment, the decrease in deferred revenue for the three months ended September 30, 2018 was primarily due to the recognition of annual subscription and maintenance billings from December 2017 and January 2018. For the nine months ended September 30, 2018, the decrease in the deferred revenue balance attributable to recognition of revenues related to the aforementioned December 2017 billings, was largely offset by the impact of the high concentration of January 2018 billings . Remaining performance obligations The following tables include the expected recognition period for the rema ining performance obligations for each reportab le segment as of September 30, 2018 : MIS Total Less than 1 year 1 - 5 years 6 - 10 Years 11 - 15 years 16-20 years Over 20 Years $ 151.3 $ 22.4 $ 68.0 $ 43.2 $ 7.5 $ 4.2 $ 6.0 The balances in the MIS table above largely reflect deferred revenue related to monitoring fees for certain structured finance products, primarily CMBS , where the issuers can elect to pay the monitoring fees for the life of the security in advance. With respect to the remaining performance obligations for the MIS segment, t he Company has applied a practical expedient set forth in ASC Topic 606 permitting the omission from the table above for unsatisfied performance obligations relating to contracts with a n original expected length of one year or less. MA Total Less than 1 Year 1 - 2 Years Over 2 Years $ 1,265.2 $ 930.1 $ 236.1 $ 99.0 The balances in the MA table above include both amounts recorded as deferred revenue on the balance sheet as of September 30, 2018 as well as amounts not yet invoiced to customers as of September 30, 2018 largely reflecting future revenue related to signed multi-year arrangements for hosted and installed subscription based products.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2018
Stock-Based Compensation [Abstract]
STOCK-BASED COMPENSATION	NOTE 4 . STOCK-BASED COMPENSATION Presented below is a summary of the stock-based compensation cost and associated tax benefit included in the accompanying consolidated statements of operations: Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Stock-based compensation cost $ 30.5 $ 31.8 $ 100.0 $ 88.9 Tax benefit $ 11.5 $ 10.3 $ 26.0 $ 28.8 During the first nine months of 2018 , th e Company granted 0.2 million employee stock options, which had a weighted av erage grant date fair value of $45.87 per share based on the Black-Scholes option-pricing model. The Company also granted 0.7 million shares of restricted stock in the first nine months of 2018 , which had a weighted av erage grant date fair value of $167.48 per share . Both the employee stock options and restricted stock generally vest rata bly over a four-year period. Ad ditionally, the Company granted 0.1 million shares of performance-based awards whereby the number of shares that ultimately vest are based on the achievement of certain non-market based performance metrics of the C ompany over a three-year period. The weighted average grant date fair value of these awards was $162.42 per share. The following weighted average assumptions were used in determining the fair value for options granted in 2018 : Expected dividend yield 1.05% Expected stock volatility 25.6% Risk-free interest rate 2.81% Expected holding period 6.2 years Grant date fair value $45.87 Unrecognized stock-based compensation expense at September 30, 2018 was $7.5 million and $164.6 million for stock options and unvested restricted stock, respectively, which is expected to be recognized over a weighted average period of 2.0 years and 2.5 years, respectively. Additionally, there was $35.2 million of unrecognized stock-based compensation expense relating to the aforementioned non-market based performance-based awards, which is expected to be recognized o ver a weighted average period of 1.8 years. The following tables summarize information relating to stock option exercises and restricted stock vesting: Nine months ended September 30, Exercise of stock options: 2018 2017 Proceeds from stock option exercises $ 36.2 $ 44.0 Aggregate intrinsic value $ 94.9 $ 75.7 Tax benefit realized upon exercise $ 23.2 $ 26.9 Number of shares exercised 0.8 1.0 Nine months ended September 30, Vesting of restricted stock: 2018 2017 Fair value of shares vested $ 150.0 $ 109.1 Tax benefit realized upon vesting $ 34.7 $ 34.6 Number of shares vested 0.9 1.0 Nine months ended September 30, Vesting of performance-based restricted stock: 2018 2017 Fair value of shares vested $ 23.0 $ 19.5 Tax benefit realized upon vesting $ 5.6 $ 6.9 Number of shares vested 0.1 0.2

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2018
Income Taxes [Abstract]
INCOME TAXES	NOTE 5 . INCOME TAXES Moody’s effective tax rate was 24.4% and 31.4% for the three month periods ended September 30, 2 018 and 2017, respectively and 21.0% and 29.0% for the nine month periods ended September 30, 2018 and 2017, respectively. The decline in the tax rate primarily reflects the impact of an enacted lower corporate tax rate in the U.S. pursuant to the Tax Act. Additionally, the ETR in 2018 includes a $ 37.5 million benefit relating to E xcess Tax Benefits on stock-based compensation as well as a net uncertain tax position benefit pursuant to statute of limitation lapses. The ETR in 2017 reflected the non-taxable CCXI g ain as well as $35.6 million in Excess Tax Benefits on stock-based com pensation partially offset by tax on the Purchase Price Hedge Gain which was taxed in a higher tax jurisdiction. On December 22, 2017, the Tax Act was signed into law which resulted in significant chan ges to U.S. corporate tax laws. The Tax Act includes a mandatory one-time deemed repatriation tax (“transition tax”) on previously untaxed accumulated earnings of foreign subsidiaries and beginning in 2018 reduces the statutory federal corporate income tax rate from 35% to 21%. Due to the c omplexities of the Tax Act, the SEC issued guidance requiring that companies provide a reasonable estimate of the impact of the Tax Act to the extent such reasonable estimate has been determined. Accordingly, as of December 31, 2017 the Company recorded a provisional estimate for the transition tax of $247.3 million . In September, 2018, the Company filed its 2017 federal income tax return and revised its estimate of the transition tax to $237.0 million, a reduction of $10.3 million from the estimate at D ecember 31, 2017. The reduction is primarily due to Proposed Regulations issued by the Internal Revenue Service and the finalization of earnings and profits calculations. A portion of the transition tax will be payable over eight years, starting in 2018, and will not accrue interest. The above revised provisional estimate may be impacted by a number of additional considerations, including but not limited to the issuance of final regulations and our ongoing analysis of the new law. As a result of the Tax Act, all previously net undistributed foreign earnings have now been subject to U.S. tax. The Company continues to evaluate which entities it will indefinitely reinvest earnings outside the U.S. The Company has provided deferred taxes for those entities whose earnings are not considered permanently reinvested outside of the U.S. The Company classifies interest related to UTP s in interest expense, net in its consoli dated statements of operations. Penalties, if incurred, would be recognized in other non- operating (expense) income, net. The Company had an increase in its UTPs of $ 73 . 5 million ($ 73 . 4 million net o f federal tax) during the third quarter of 2018 and a net increase in its UTP s during the f irst nine months of 2018 of $ 82.7 million ($ 80.9 milli on net of federal tax). The movement in UTP s was primarily related to the additional reserves established for non-U.S. tax matters and an adjustment to the transition tax under U.S. tax reform. The Company has recorded a deferred tax asset in the amount of $54.4 million for potential transition tax benefits if certain non-U.S. UTPs are not sustained. Moody’s Corporation and subsidiaries are subject to U.S. federal income tax as well as income tax in various state, local and foreign jurisdictions. The Com pany’s U.S. federal income tax returns for 2013 , 2015 through 2 017 remain open to examination. The Company’s New York State tax returns for 2011 through 2014 are currently under examination and the Company’s New York City tax return for 2014 is currently under examination. The Company’s U.K. tax return for 2012 is currently under examination and its returns for 2013 through 2016 remain open to examination. For ongoing audits, it is possible the balance of UTP s could decrease in the next twelve months as a result of the settlement of these audits, which might involve the payment of additional taxes, the adjustment of certain deferred taxes and/or the recognition of tax benefits. It is also possible that new issues might be raised by tax authorities which c ould necessitate increases to the balance of UTP s. As the Company is unable to predict the timing or outcome of these audits, it is therefore unable to estimate the amount of changes to the balance of UTP s at this time. However, the Company believes that it has adequately provided for its financial exposure relating to all open tax years by tax jurisdiction in accordance with the applicable provisions of Topic 740 of the ASC regarding UTP s. The following table shows the a mount the Company paid for income taxes: Nine months ended September 30, 2018 2017 Income taxes paid $ 337.0 $ 194.7

WEIGHTED AVERAGE SHARES OUTSTAN

WEIGHTED AVERAGE SHARES OUTSTANDING	9 Months Ended
	Sep. 30, 2018
Weighted Average Shares Outstanding [Abstract]
WEIGHTED AVERAGE SHARES OUTSTANDING	NOTE 6 . WEIGHTED AVERAGE SHARES OUTSTANDING Below is a reconciliation of basic to diluted shares outstanding: Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Basic 191.8 191.1 191.7 191.1 Dilutive effect of shares issuable under stock-based compensation plans 2.7 3.0 2.7 3.0 Diluted 194.5 194.1 194.4 194.1 Anti-dilutive options to purchase common shares and restricted stock as well as contingently issuable restricted stock which are excluded from the table above 0.3 0.5 0.4 0.6 The calculation of diluted EPS requires certain assumptions regarding the use of both cash proceeds and assumed proceeds that would be received upon the exercise of stock options and vesting of restricted stock outstanding as of September 30, 2018 and 2017 .

CASH EQUIVALENT AND INVESTMENTS

CASH EQUIVALENT AND INVESTMENTS	9 Months Ended
	Sep. 30, 2018
Cash and Cash Equivalents [Abstract]
CASH EQUIVALENT AND INVESTMENT	NOTE 7 . CASH EQUIVALENTS AND INVESTMENTS The table below provides additional information on the Company’s cash equivalents and investments: As of September 30, 2018 Balance sheet location Cost Gross Unrealized Gains Fair Value Cash and cash equivalents Short-term investments Other assets Money market mutual funds $ 32.3 $ - $ 32.3 $ 32.3 $ - $ - Certificates of deposit and money market deposit accounts (1) $ 324.0 $ - $ 324.0 $ 202.2 $ 110.7 $ 11.1 Open ended mutual funds $ 31.1 $ 3.6 $ 34.7 $ - $ - $ 34.7 As of December 31, 2017 Balance sheet location Cost Gross Unrealized Gains Fair Value Cash and cash equivalents Short-term investments Other assets Money market mutual funds $ 42.2 $ - $ 42.2 $ 42.2 $ - $ - Certificates of deposit and money market deposit accounts (1) $ 351.4 $ - $ 351.4 $ 238.6 $ 111.8 $ 1.0 Fixed maturity and open ended mutual funds (2) $ 16.8 $ 4.3 $ 21.1 $ - $ - $ 21.1 (1) Consists of time deposits and money market deposit accounts. The remaining contractual maturities for the certificates of deposits classified as short-term investments were one to 12 months at both September 30, 2018 and December 31, 2017. The remaining contractual maturities for the certificates of deposits classified in other assets are 13 to 39 months at September 30, 2018 and 15 to 48 months at December 31, 2017. Time deposits with a maturity of less than 90 days at time of purchase are classified as cash and cash equivalents. (2) At December 31, 2017, the remaining contractual maturities for the fixed maturity instruments were six months to seven months. As a result of the adoption of ASU 2016-01, as further discussed in Note 1 and Note 2, the money market mutual funds and the fixed maturity and open- ended mutual funds in the table above are deemed to be equity securities with readily determinable fair value s with changes in the fair value recognized through net income under ASC Topic 32 1. The fair value of these instruments is determined using Level 1 inputs as defined in the ASC .

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2018
Acquisitions [Abstract]
ACQUISITIONS	NOTE 8 . ACQUISITIONS The business combinations described below are accounted for using the acquisition method of accounting whereby assets acquired and liabilities assumed were recognized at fair value on the date of the transaction. Any excess of the purchase price over the fair value of the assets acquired and liabilities assumed was recorded to goodwill. Omega Performance On August 1 6 , 2018, the Company acquired 100 % of Omega Performance, a provider of online credit training. The aggregate purchase price was not material and the near term impact to the Company’s operations and cash flows is not expected to be material. This business operates in the MA reportable segment and goodwill related to this acquisition has been allocated to the MALS reporting unit. Bureau van Dijk On August 10, 2017, a subsidiary of the Company acquired 100% of Yellow Maple I B.V., an indirect parent company of Bureau van Dijk Electronic Publishing B.V., a global provider of business intelligence and company informatio n products. The cash payment of $3,542.0 million was funded with a combination of cash on hand, primarily offshore, and new debt financing. The acquisition extends Moody’s position as a leader in risk data and analytical insight. Shown below is the final purchase price allocation, which summarizes the fair value of the assets and liabilities assumed, at the date of acquisition: (Amounts in millions) Current assets $ 158.4 Property and equipment, net 4.2 Intangible assets: Customer relationships (23 year weighted average life) $ 998.7 Product technology (12 year weighted average life) 258.5 Trade name (18 year weighted average life) 82.3 Database (10 year weighted average life) 12.9 Total intangible assets (21 year weighted average life) 1,352.4 Goodwill 2,614.7 Other assets 5.9 Liabilities Deferred revenue $ (101.1) Accounts payable and accrued liabilities (44.3) Deferred tax liabilities, net (329.8) Other liabilities (118.4) Total liabilities (593.6) Net assets acquired $ 3,542.0 The Company has completed the valuation analysis of the fair market value of assets and liabilities of the Bureau van Dijk business. Current assets in the table ab ove include acquired cash of $36.0 million. Additionally, current assets include accounts receivable of approximately $88.0 million (net of an allowance fo r uncollectible accounts of 3.7 million). The acquired deferred revenue balance of approximately $154 millio n was reduced by $53 million as part of acquisition accounting to establish the fair value of deferred revenue. This will reduce reported revenue by $53 million over the remaining contractual period of in-progress customer arrangements assumed as of the ac quisition date. Th is resulted in approximately $ 1 million and $ 17 million less in reported revenue for the three and nine months ended September 30, 2018, respectively, wi th the remaining approximate $1 million to reduce revenue in the fourth quarter of 2018. Amortization of acquired intangible assets was $ 17.6 million and $ 54.2 million for three months and nine months ended September 30, 2018, respectively, compared to $10.0 million in each of the same periods ended September 30, 2017. Goodwi ll Under the acquisition method of accounting for business combinations, the excess of the purchase price over the fair value of the net assets acquired is allocated to goodwill. Goodwill typically results through expected synergies from combining operatio ns of an acquiree and an acquirer, anticipated new customer acquisition and products, as well as from intangible assets that do not qualify for separate recognition. The goodwill recognized as a result of this acquisition includes, among other things, the value of combining the complementary product portfolios of the Company and Bureau van Dijk, which is expected to extend the Company’s reach to new and evolving market segments as well as cost savings synergies, expected new customer acquisitions and produc ts. Goodwill, which has been assigned to the MA segment, is not deductible for tax purposes. Bureau van Dijk is a separate reporting unit for purposes of the Company’s annual goodwill impairment assessment. Other Liabilities Assumed In connection with the acquisition, the Company assumed liabilities relating to UTPs as well as deferred tax liabilities which relate to acquired intangible assets. These items are included in other liabilities in the table above. Supplementary Unaudited Pro Forma Information Supplemental information on an unaudited pro forma basis is presented below for the nine months ended September 30 , 2017 as if the acquisition of Bureau van Dijk occurred on January 1, 2016. The pro forma financial information is presented for comparative purposes only and is based on certain estimates and assumptions, which the Company believes to be reasonable but not necessarily indicative of future results of operations or the results that would have been reported if the acquisition had been completed a t January 1, 2016. The unaudited pro forma information includes amortization of acquired intangible assets based on the purchase price allocation and an estimate of useful lives reflected above, and incremental financing costs resulting from the acquisitio n, net of income tax, which was estimated using the weighted average statutory tax rates in effect in the jurisdiction for which the pro forma adjustment relates. (Amounts in millions) For nine months ended September 30, 2017 Pro forma Revenue $ 3,226.9 Pro forma Net Income attributable to Moody's $ 965.9 The unaudited pro forma results do not include any anticipated cost savings or other effects of the planned integration of Bureau van Dijk . Accordingly, the pro forma results above are not necessarily indicative of the results that would have been reported if the acquisition had occurred on the dates indicated, nor are the pro forma results indicative of results which may occur in the future. The Bureau van Dijk results included in the table above have been converted to U.S. GAAP from IFRS as issue d by the IASB and have been translated to USD at rates in eff ect for the periods presented.

DERIVATIVE INSTRUMENTS AND HEDG

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities [Abstract]
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	NOTE 9 . DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES The Company is exposed to global market risks, including risks from changes in FX rates and changes in interest rates. Accordingly, the Company uses derivatives in certain instances to manage the aforementioned financial exposures that occur in the normal course of business. The Company does not hold or issue derivatives for speculative purposes. Derivatives and non-derivative instruments designated as accounting hedges: Interest Rate Swaps The Com pany has entered into interest rate swaps to convert the fixed interest rate on certain of its long-term debt to a floating interest rate based on the 3-month LIBOR. The purpose of these hedges is to mitigate the risk associated with changes in the fair va lue of the long-term debt, thus the Company has designated these swaps as fair value hedges. The fair value of the swaps is adjusted quarterly with a corresponding adjustment to the carrying value of the debt. The changes in the fair value of the swaps and the underlying hedged item generally offset and the net cash settlements on the swaps are recorded each period within interest expense, net in the Company’s consolidated statement of operations. The following table summarizes the Company’s interest rate s waps designated as fair value hedges: Refer to Note 15 for information on the cumulative amount of fair value hedging adjustments included in the carrying amount of the above hedged items. The following table summarizes the impact to the statement of operations of the Company’s interest rate swaps designated as fair value hedges : Amount of income/(loss) recognized in the consolidated statements of operations Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Total amounts of financial statement line item presented in the statements of operations in which the effects of fair value hedges are recorded Interest expense, net $ (56.4) $ (53.1) $ (160.5) $ (150.2) Descriptions Location on Statement of Operations Net interest settlements and accruals on interest rate swaps Interest expense, net $ (0.5) $ 1.6 $ (1.0) $ 5.8 Fair value changes on interest rate swaps Interest expense, net $ (3.3) $ (2.3) $ (14.8) $ (2.2) Fair value changes on hedged debt Interest expense, net $ 3.3 $ 2.3 $ 14.8 $ 2.2 Cash flow hedges In conjunction with the issuance of the 2015 Senior Notes, the Company entered into a cr oss-currency swap to exchange € 100 million for U.S. dollars on the date of the settlement of the notes. The purpose of this cross-currency swap was to mitigate FX risk on the remaining principal balance on the 2015 Senior Notes that initially was not designated as a net investment hedge. Under the terms of the swap, the Company paid the counterparty interest on the $110.5 million received at 3.945% per annum and the counterparty pai d the Company interest on the € 100 million paid at 1.75% per annum. These interest payments were settled in March of each year, beginning in 2016, until early termination of the cross-currency sw ap in 201 7 which was a t the discretion of the Company . In March 2016, the Company designated these cross-currency swaps as cash flow hedges. Accordingly, changes in fair value subsequent to the date the swaps were designated as cash flow hedges were recogn ized in OCI. Gains and losses on the swaps initially recognized in OCI were reclassified to the statement of operations in the period in which changes in the underlying hedged item affects net income. On December 18, 2017, when the Company terminated the c ross-currency swap, it designated the full € 500 million principal of the 2015 Senior Notes as a net investment hedge as discussed below. Net investment hedges The Company has designated € 500 million of the 2015 Senior Notes Due 2027 as a net investment hed ge. This hedge is intended to mitigate FX exposure related to a portion of the Company’s euro net investment in certain foreign subsidiaries against changes in euro/USD exchange rates. This net investment hedge is designated as an accounting hedge under th e applicable sections of Topic 815 of the ASC and will end upon the repayment of the notes in 2027 unless terminated earlier at the discretion of the Company. In addition, during the second quarter of 2018 the Company entered into cross-currency swaps to e xchange an aggregate amount of €490.1 million with corresponding interest based on the floating 3-month EURIBOR for an aggregate amount of $580.0 million with corresponding interest based on the floating 3-month U.S. LIBOR, which were designated as net inv estment hedges under ASC Topic 815. The purpose of these cross-currency swaps is to mitigate FX exposure related to a portion of the Company’s euro net investments in certain foreign subsidiaries against changes in euro/USD exchange rates. These hedges wil l expire and be settled in 2021 and 2022 for €422.5 million and €67.6 million of the total notional amount, respectively, unless terminated early at the discretion of the Company. Beginning in 2018 with the Company’s initial application of ASU 2017-12, net periodic interest settlements and accruals on the cross currency swaps (which would include any cross-currency basis spread adjustment) are reported directly in interest expense, net. Changes in the fair value of the cross-currency swaps resulting from c hanges in the foreign exchange spot rate will continue to be recorded within the cumulative translation component of OCI. The following table provides information on the gains/(losses) on the Company’s net investment and cash flow hedges: Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing) Derivative and Non-Derivative Instruments in Net Investment Hedging Relationships Three Months Ended Three Months Ended Three Months Ended September 30, September 30, September 30, 2018 2017 (a) 2018 2017 (a) 2018 (c) 2017 (d) Cross currency swaps $ 1.8 $ - $ - $ - $ 4.1 $ - FX forwards - 0.4 - - - - Long-term debt 2.2 (10.3) - - - - Total net investment hedges $ 4.0 $ (9.9) $ - $ - $ 4.1 $ - Derivatives in Cash Flow Hedging Relationships Cross currency swap $ - $ 3.2 $ 0.1 $ 2.6 (b) $ - $ - Interest rate contracts - - - - - - Total cash flow hedges $ - $ 3.2 $ 0.1 $ 2.6 $ - $ - Total $ 4.0 $ (6.7) $ 0.1 $ 2.6 $ 4.1 $ - Derivative and Non-Derivative Instruments in Net Investment Hedging Relationships Nine months ended Nine months ended Nine months ended September 30, September 30, September 30, 2018 2017 (a) 2018 2017 (a) 2018 (c) 2017 (d) Cross currency swaps $ 5.8 $ - $ $ - $ 6.2 $ - FX forwards - 1.2 - - - - Long-term debt 14.7 (31.4) - - - - Total net investment hedges $ 20.5 $ (30.2) $ - $ - $ 6.2 $ - Derivatives in Cash Flow Hedging Relationships Cross currency swap $ 1.5 $ 6.6 $ 0.3 $ 7.9 (b) $ - $ 0.4 Interest rate contracts - (0.4) - (1.1) - - Total cash flow hedges $ 1.5 $ 6.2 $ 0.3 $ 6.8 $ - $ 0.4 Total $ 22.0 $ (24.0) $ 0.3 $ 6.8 $ 6.2 $ 0.4 (a) For the three and nine months ended September 30, 2017, amount of gain or (loss) represents only the effective portion of the hedging relationship as this period was prior to the Company’s 2018 initial application of ASU 2017-12. (b) For the three and nine months ended September 30, 2017, reflects $4.2 million and $12.8 million, respectively in gains recorded in other non-operating income (expense), net and $1.6 million and $4.9 million relating to the tax effect of the aforementioned item. (c) Effective with the adoption of ASU 2017-12, the Company has elected to assess the effectiveness of its net investment hedges based on changes in spot exchange rates. Accordingly, amounts recognized directly into Net Income during the three and nine months ended September 30, 2018 related to its cross-currency swaps represent net periodic interest settlements and accruals which are recognized in interest expense, net. (d) For the three and nine months ended September 30, 2017, amount of gain or (loss) recognized directly into income represents the ineffective portion of the hedging relationship. No hedging instruments for which ineffectiveness was recognized directly into Net Income in 2017 or in years prior were outstanding at the date of adoption of ASU 2017-12. The cumulative amount of net investment hedge and cash flow hedge gains (losses) remaining in AOCI is as follows: Cumulative Gains/(Losses), net of tax September 30, December 31, 2018 2017 Net investment hedges Cross currency swaps $ 5.8 $ - FX forwards 23.5 23.5 Long-term debt (10.0) (24.7) Total net investment hedges $ 19.3 $ (1.2) Cash flow hedges Interest rate contracts $ (0.4) $ (0.4) Cross currency swap 2.5 1.3 Total cash flow hedges 2.1 0.9 Total net gain (loss) in AOCI $ 21.4 $ (0.3) Derivatives not designated as accounting hedges: Foreign exchange forwards The Company also enters into foreign exchange forwards to mitigate the change in fair value on certain assets and liabilities denominated in currencies other than a subsidiary’s functional currency. These forward contracts are not designated as accounting hedges under the applicable sections of Topic 815 of the ASC. Accordingly, changes in the fair value of these contracts are recognized immediately in other non-operating (expense ) income, net in the Company’s consolidated statements of operations along with the FX gain or loss recognized on the assets and liabilities denominated in a currency other than the subsidiary’s functional currency. These contracts have expiration dates a t various times through January 2019. The following table summarizes the notional amounts of the Company’s outstanding foreign exchange forwards: September 30, December 31, 2018 2017 Notional amount of currency pair: Sell Buy Sell Buy Contracts to sell USD for GBP $ 556.8 £ 415.9 $ 484.7 £ 362.3 Contracts to sell USD for Japanese Yen $ 25.5 ¥ 2,700.0 $ 24.3 ¥ 2,700.0 Contracts to sell USD for Canadian dollars $ 85.0 C$ 109.0 $ 51.7 C$ 64.0 Contracts to sell USD for Singapore dollars $ - S$ - $ 39.2 S$ 53.0 Contracts to sell USD for Euros $ 200.8 € 169.9 $ 465.2 € 390.0 NOTE: € = Euro, £ = British pound, $ = U.S. dollar, ¥ = Japanese Yen, C$ = Canadian dollar, S$= Singapore dollars Foreign Exchange Options The Company entered into a foreign currency collar in 2017 consisting of option contracts to economically hedge the Bureau van Dijk euro denominated purchase price (as discussed further in Note 8 of the financial stateme nts). These option contracts were not designated as accounting hedges under the applicable sections of Topic 815 of the ASC. The foreign currency option contracts consist ed of separate put and call options each in the aggregate notional amount of €2.7 billion. This collar was settled at the end of July 2017, in advance of the August 10, 2017 closing of the Bureau van Dijk acquisition. The Company entered into foreign exchange forwards to hedge the Bureau van Dijk purchase price for the period from the settleme nt of the aforementioned foreign currenc y collar until the closing date on August 10, 2017. These forward contracts were not designated as accounting hedges under the applicable sections of Topic 815 of the ASC. The foreign exchange contracts were to sell $2.8 billion and buy € 2.4 billion and sell $41 million and buy £31 million. The following table summarizes the impact to the consolidated statements of operations relating to the net (losses) gains on the Company’s derivatives which are not designated as hedging instruments: Three Months Ended Nine Months Ended September 30, September 30, Derivatives not designated as accounting hedges Location on Statement of Operations 2018 2017 2018 2017 Foreign exchange forwards Other non-operating income, net $ (11.8) $ 9.2 $ (29.1) $ 14.0 FX collar relating to Bureau van Dijk acquisition Purchase Price Hedge Gain - 59.6 - 100.8 Foreign exchange forwards relating to Bureau van Dijk acquisition Purchase Price Hedge Gain - 10.3 - 10.3 $ (11.8) $ 79.1 $ (29.1) $ 125.1 The table below shows the classification between assets and liabilities on the Company’s consolidated balance sheets for the fair value of the derivative instrument as well as the carrying value of its non-derivative debt instruments designated and qualifying as net investment hedges : Derivative and Non-Derivative Instruments Balance Sheet Location September 30, 2018 December 31, 2017 Assets: Derivatives designated as accounting hedges: Cross-currency swaps designated as net investment hedges Other current assets $ 7.8 $ - Interest rate swaps Other assets - 0.5 Total derivatives designated as accounting hedges 7.8 0.5 Derivatives not designated as accounting hedges: FX forwards on certain assets and liabilities Other current assets 2.5 12.5 Total assets $ 10.3 $ 13.0 Liabilities: Derivatives designated as accounting hedges: Interest rate swaps Other current liabilities $ 3.8 $ - Interest rate swaps Other non-current liabilities 14.0 3.5 Total derivatives designated as accounting hedges 17.8 3.5 Non-derivative instrument designated as accounting hedge Long-term debt designated as net investment hedge Long-term debt 580.7 600.4 Derivatives not designated as accounting hedges: FX forwards on certain assets and liabilities Accounts payable and accrued liabilities 20.5 2.0 Total liabilities $ 619.0 $ 605.9

GOODWILL AND OTHER ACQUIRED INT

GOODWILL AND OTHER ACQUIRED INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2018
Goodwill And Other Acquired Intangible Assets [Abstract]
GOODWILL AND OTHER ACQUIRED INTANGIBLE ASSETS	NOTE 10 . GOODWILL AND OTHER ACQUIRED INTANGIBLE ASSETS The following table summarizes the activity in goodwill for the periods indicated: Nine months ended September 30, 2018 MIS MA Consolidated Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Balance at beginning of year $ 285.2 $ - $ 285.2 $ 3,480.2 $ (12.2) $ 3,468.0 $ 3,765.4 $ (12.2) $ 3,753.2 Additions/adjustments - - - 23.8 - 23.8 23.8 - 23.8 Foreign currency translation adjustments (13.1) - (13.1) (102.6) - (102.6) (115.7) - (115.7) Ending balance $ 272.1 $ - $ 272.1 $ 3,401.4 $ (12.2) $ 3,389.2 $ 3,673.5 $ (12.2) $ 3,661.3 Year ended December 31, 2017 MIS MA Consolidated Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Balance at beginning of year $ 277.0 $ - $ 277.0 $ 758.8 $ (12.2) $ 746.6 $ 1,035.8 $ (12.2) $ 1,023.6 Additions/adjustments - - - 2,622.6 - 2,622.6 2,622.6 - 2,622.6 Foreign currency translation adjustments 8.2 - 8.2 98.8 - 98.8 107.0 - 107.0 Ending balance $ 285.2 $ - $ 285.2 $ 3,480.2 $ (12.2) $ 3,468.0 $ 3,765.4 $ (12.2) $ 3,753.2 The 2018 additions/adjustments for the MA segment in the table above relate to the acquisition of Omega Performance coupled with certain immaterial adjustments relating to Bureau van Dijk’s acquired accounts payable and accrued liabilities as of the acquisition date. The 2017 additions/adjustments for the MA segment in the table above relate to the acquisition of Bureau van Dijk and structured finan ce data and analytics business of SCDM. Acquired intangible assets and related amortization consisted of: September 30, December 31, 2018 2017 Customer relationships $ 1,312.3 $ 1,345.1 Accumulated amortization (200.9) (159.9) Net customer relationships 1,111.4 1,185.2 Trade secrets 30.1 30.2 Accumulated amortization (28.3) (28.1) Net trade secrets 1.8 2.1 Software/product technology 348.8 358.6 Accumulated amortization (96.2) (78.0) Net software/product technology 252.6 280.6 Trade names 156.4 161.6 Accumulated amortization (33.0) (26.7) Net trade names 123.4 134.9 Other (1) 58.9 57.4 Accumulated amortization (30.5) (28.6) Net other 28.4 28.8 Total acquired intangible assets, net $ 1,517.6 $ 1,631.6 (1) Other intangible assets primarily consist of databases, covenants not to compete, and acquired ratings methodologies and models. Amortization expense relating to acquired intangible assets is as follows: Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Amortization expense $ 24.6 $ 18.8 $ 75.4 $ 35.9 Estimated future amortization expense for acquired intangible assets subject to amortization is as follows: Year Ending December 31, 2018 (after September 30) $ 25.1 2019 95.5 2020 93.1 2021 92.9 2022 92.2 Thereafter 1,118.8 Total estimated future amortization $ 1,517.6 Amortizable intangible assets are reviewed for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If the estimated undiscounted future cash flows are lower than the carrying amount of the related asset, a loss is recognized for the difference between the carrying amount and the estimated fair value of the asset. There were no impairments to intangible assets during the nine months ended September 30, 2018 and 2017.

FAIR VALUE

FAIR VALUE	9 Months Ended
	Sep. 30, 2018
Fair Value [Abstract]
FAIR VALUE	NOTE 11 . FAIR VALUE The table below presents information about items that are carried at fair value at September 30, 2018 and December 31, 2017 : Fair Value Measurement as of September 30, 2018 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 10.3 $ - $ 10.3 Money market mutual funds 32.3 32.3 - Open ended mutual funds 34.7 34.7 - Total $ 77.3 $ 67.0 $ 10.3 Liabilities: Derivatives (a) $ 38.3 $ - $ 38.3 Total $ 38.3 $ - $ 38.3 Fair Value Measurement as of December 31, 2017 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 13.0 $ - $ 13.0 Money market mutual funds 42.2 42.2 - Fixed maturity and open ended mutual funds 21.1 21.1 - Total $ 76.3 $ 63.3 $ 13.0 Liabilities: Derivatives (a) $ 5.5 $ - $ 5.5 Total $ 5.5 $ - $ 5.5 (a) Represents FX forwards on certain assets and liabilities as well as interest rate swaps and cross-currency swaps as more fully described in Note 9 to the condensed consolidated financial statements. Fair Value Measurement as of September 30, 2018 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 10.3 $ - $ 10.3 Money market mutual funds 32.3 32.3 - Open ended mutual funds 34.7 34.7 - Total $ 77.3 $ 67.0 $ 10.3 Liabilities: Derivatives (a) $ 38.3 $ - $ 38.3 Total $ 38.3 $ - $ 38.3 Fair Value Measurement as of December 31, 2017 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 13.0 $ - $ 13.0 Money market mutual funds 42.2 42.2 - Fixed maturity and open ended mutual funds 21.1 21.1 - Total $ 76.3 $ 63.3 $ 13.0 Liabilities: Derivatives (a) $ 5.5 $ - $ 5.5 Total $ 5.5 $ - $ 5.5 (a) Represents FX forwards on certain assets and liabilities as well as interest rate swaps and cross-currency swaps as more fully described in Note 9 to the condensed consolidated financial statements. The following are descriptions of the methodologies utilized by the Company to estimate the fair value of its derivative contracts, fixed maturity plans, and money market mutual funds: Derivatives: In determining the fair value of the derivative contracts in the table above, the Company utilizes industry standard valuation models. Where applicable, these models project future cash flows and discount the future amounts to a present value using spot rates, forward points, currency volatilities, inte rest rates as well as the risk of non-performance of the Company and the counterparties with whom it has derivative contracts. The Company established strict counterparty credit guidelines and only enters into transactions with financial institutions that adhere to these guidelines. Accordingly, the risk of counterparty default is deemed to be minimal. Fixed maturity and open-ended mutual funds: As a result of the adoption of ASU 2016-01, as further discussed in Note 1 and Note 2, the fixed maturity and o pen- ended mutual funds in the table above are deemed to be equity securities with readily determinable fair values with changes in the fair value recognized through net income under ASC Topic 321. Prior to the Company’s adoption of ASU No. 2016-01, any un realized gains and losses were recognized through OCI until the instruments mature d or were sold. The fair value of these instruments is determined using Level 1 inputs as defined in the ASC. Money market mutual funds: Similar to fixed maturity and open- e nded mutual funds , the money market mutual funds in the table above are deemed to be equity securities with readily determinable fair values with changes in the fair value recognized through net income under ASC Topic 321 as required by ASU 2016-01. The mo ney market mutual funds represent publicly traded funds with a stable $ 1 net asset value.

OTHER BALANCE SHEET AND STATEME

OTHER BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION	9 Months Ended
	Sep. 30, 2018
Other Balance Sheet And Statement Of Operations Information [Abstract]
OTHER BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION	NOTE 12 . OTHER BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION The following tables contain additional detail related to certain balance sheet captions: September 30, December 31, 2018 2017 Other current assets: Prepaid taxes $ 77.1 $ 94.9 Prepaid expenses 78.9 91.7 Capitalized costs to obtain and fulfill sales contracts (1) 39.3 15.9 Other 43.6 47.6 Total other current assets $ 238.9 $ 250.1 September 30, December 31, 2018 2017 Other assets: Investments in joint ventures $ 98.3 $ 99.1 Deposits for real-estate leases 13.0 12.3 Indemnification assets related to acquisitions 15.8 17.0 Mutual funds and fixed deposits 45.8 22.1 Costs to obtain sales contracts (1) 68.0 - Other 2.7 9.4 Total other assets $ 243.6 $ 159.9 (1) The 2018 amount reflects capitalized costs to obtain sales contracts (sales commissions) pursuant to the adoption of the New Revenue Accounting Standard, which are amortized over an average 7 year period as well as costs incurred and capitalized for in process ratings (current assets only). September 30, December 31, 2018 2017 Accounts payable and accrued liabilities: Salaries and benefits $ 91.9 $ 129.6 Incentive compensation 133.7 246.7 Customer credits, advanced payments and advanced billings 23.2 22.2 Self-insurance reserves 13.1 8.1 Dividends 5.6 6.2 Professional service fees 50.7 47.1 Interest accrued on debt 36.2 73.9 Accounts payable 16.2 21.8 Income taxes 79.9 79.2 Pension and other retirement employee benefits (see Note 14) 5.9 5.9 Accrued royalties 13.5 26.4 Foreign exchange forwards on certain assets and liabilities 20.5 2.0 Other 91.2 81.2 Total accounts payable and accrued liabilities $ 581.6 $ 750.3 September 30, December 31, 2018 2017 Other liabilities: Pension and other retirement employee benefits (see Note 14) $ 252.7 $ 244.5 Deferred rent - non-current portion 96.6 103.1 Interest accrued on UTPs 65.0 54.7 Other tax matters 1.3 1.3 Income tax liability - non-current (2) 122.6 232.2 Interest rate swaps 14.0 3.5 Other 22.7 24.7 Total other liabilities $ 574.9 $ 664.0 (2) Primarily reflects the transition tax pursuant to the Tax Act, which was enacted into law in December 2017. Changes in the Company’s self-insurance reserves for claims insured by the Company’s wholly-owned insurance subsidiary, which primarily relate to legal defense costs for claims from prior years, are as follows: Nine months ended Year Ended September 30, December 31, 2018 2017 Balance January 1, $ 8.1 $ 11.1 Accruals (reversals), net 4.9 9.6 Payments 0.1 (12.6) Balance $ 13.1 $ 8.1 Other Non-Operating Income (Expense): The following table summarizes the components of other non-operating income (expense): Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 FX loss $ (3.9) $ (6.7) $ (3.6) $ (12.5) Net periodic pension costs - other components (1) 2.6 1.9 7.8 5.7 Joint venture income 3.3 2.7 9.2 7.7 Other 0.4 2.6 4.9 2.3 Total $ 2.4 $ 0.5 18.3 $ 3.2 (1) The Company adopted ASU No. 2017-07 in the first quarter of 2018, whereby all components of pension expense except for the service cost component are required to be presented in other non-operating income. The service cost component continues to be reported as an operating expense. Noncontrolling Interests : The following table summarizes the changes in the Company’s noncontrolling interests : Non-Controlling Interests Balance at December 31, 2016 $ 197.7 Net income 7.1 Dividends (3.3) Purchase of noncontrolling interest (1.0) Non-controlling interests portion of foreign currency translation adjustments 13.0 Net realized and unrealized gain on available for sale securities (0.7) Balance at December 31, 2017 $ 212.8 Net income 7.4 Dividends (4.0) Non-controlling interests portion of foreign currency translation adjustments (10.2) Balance at September 30, 2018 $ 206.0

COMPREHENSIVE INCOME AND ACCUMU

COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME	9 Months Ended
	Sep. 30, 2018
Comprehensive Income And Accumulated Other Comprehensive Income [Abstract]
COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME	NOTE 13 . COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME The following table provides details about the reclassifications out of AOCI: Three Months Ended September 30, 2018 Nine months ended September 30, 2018 Affected line in the consolidated statement of operations Gains on cash flow hedges Cross-currency swap $ 0.1 $ 0.3 Interest expense, net Income tax effect of items above - - Provision for income taxes Total net gains on cash flow hedges 0.1 0.3 Pension and other retirement benefits Amortization of actuarial losses and prior service costs included in net income (0.6) (2.2) Operating expense Amortization of actuarial losses and prior service costs included in net income (0.5) (1.3) SG&A expense Total before income taxes (1.1) (3.5) Income tax effect of item above 0.3 1.0 Provision for income taxes Total pension and other retirement benefits (0.8) (2.5) Total losses included in Net Income attributable to reclassifications out of AOCI $ (0.7) $ (2.2) Three Months Ended September 30, 2017 Nine months ended September 30, 2017 Affected line in the consolidated statement of operations Gains on cash flow hedges Cross-currency swap $ 3.5 $ 12.1 Other non-operating expense, net Treasury rate lock 0.7 (0.4) Interest expense, net Total before income taxes 4.2 11.7 Income tax effect of item above (1.6) (4.9) Provision for income taxes Total net gains on cash flow hedges 2.6 6.8 Gains on available for sale securities: Gains on available for sale securities 1.1 1.1 Other non-operating income (expense), net Total gains on available for sale securities 1.1 1.1 Pension and other retirement benefits Amortization of actuarial losses and prior service costs included in net income (1.3) (4.0) Operating expense Amortization of actuarial losses and prior service costs included in net income (0.8) (2.4) SG&A expense Total before income taxes (2.1) (6.4) Income tax effect of item above 0.8 2.5 Provision for income taxes Total pension and other retirement benefits (1.3) (3.9) Total net gains included in Net Income attributable to reclassifications out of AOCI $ 2.4 $ 4.0 The following table shows changes in AOCI by component (net of tax): Three Months Ended September 30, 2018 September 30, 2017 Gains/(Losses) Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Balance June 30, $ (58.6) $ 2.2 $ (248.4) $ - $ (304.8) $ (72.0) $ 0.5 $ (241.8) $ 3.6 $ (309.7) Other comprehensive income/(loss) before reclassifications - - (37.9) - (37.9) - 3.2 50.8 0.3 54.3 Amounts reclassified from AOCI 0.8 (0.1) - - 0.7 1.3 (2.6) - (1.1) (2.4) Other comprehensive income/(loss) 0.8 (0.1) (37.9) - (37.2) 1.3 0.6 50.8 (0.8) 51.9 Balance September 30, $ (57.8) $ 2.1 $ (286.3) $ - $ (342.0) $ (70.7) $ 1.1 $ (191.0) $ 2.8 $ (257.8) Nine months ended September 30, 2018 September 30, 2017 Gains/(Losses) Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Balance December 31, $ (61.5) $ 0.9 $ (113.9) $ 2.3 $ (172.2) $ (79.5) $ 1.7 $ (290.2) $ 3.1 $ (364.9) Adoption of ASU 2016-01 (Refer to Note 1 and Note 2) - - - (2.3) (2.3) - - - - - Other comprehensive income/(loss) before reclassifications 1.2 1.5 (172.4) - (169.7) 4.9 6.2 99.2 0.8 111.1 Amounts reclassified from AOCI 2.5 (0.3) - - 2.2 3.9 (6.8) - (1.1) (4.0) Other comprehensive income/(loss) 3.7 1.2 (172.4) (2.3) (169.8) 8.8 (0.6) 99.2 (0.3) 107.1 Balance September 30, $ (57.8) $ 2.1 $ (286.3) $ - $ (342.0) $ (70.7) $ 1.1 $ (191.0) $ 2.8 $ (257.8)

PENSION AND OTHER POST-RETIREME

PENSION AND OTHER POST-RETIREMENT BENEFITS	9 Months Ended
	Sep. 30, 2018
Pension And Other Retirement Benefits [Abstract]
PENSION AND OTHER RETIREMENT BENEFITS	NOTE 14 . PENSION AND OTHER RETIREMENT BENEFITS M oody’s maintains funded and unfunded noncontributory Defined Benefit Pension Plans. The U.S. plans provide defined benefits using a cash balance formula based on years of service and career average salary for its employees or final average pay for selected executives. The Company also provides certain healthcare and life insurance benefits for retired U.S. employees. The retirement healthcare plans are contributory; the life insurance plans are noncontribu tory. Moody’s funded and unfunded U.S. pension plans, the U.S. retirement healthcare plans and the U.S. retirement life insurance plans are collectively referred to herein as the “Retirement Plans”. The U.S. retirement healthcare plans and the U.S. retirem ent life insurance plans are collectively referred to herein a s the “Other Retirement Plans”. The non - U.S. defined benefit pension plan are immaterial. Effective January 1, 2008, the Company no longer offers DBPPs to U.S. employees hired or rehired on or a fter January 1, 2008. New U.S. employees will instead receive a retirement contribution of similar benefit value under the Company’s Profit Participation Plan. Current participants of the Company’s DBPPs continue to accrue benefits b ased on existing plan f ormulas. The components of net periodic benefit expense related to the Retirement Plans are as follows: Three Months Ended September 30, Pension Plans Other Retirement Plans 2018 2017 2018 2017 Components of net periodic expense Service cost $ 4.6 $ 4.6 $ 0.7 $ 0.7 Interest cost 4.4 4.7 0.3 0.2 Expected return on plan assets (3.8) (4.1) - - Amortization of net actuarial loss from earlier periods 1.5 2.1 - 0.1 Amortization of net prior service costs from earlier periods - - (0.1) (0.1) Net periodic expense $ 6.7 $ 7.3 $ 0.9 $ 0.9 Nine months ended September 30, Pension Plans Other Retirement Plans 2018 2017 2018 2017 Components of net periodic expense Service cost $ 14.0 $ 13.8 $ 2.2 $ 1.9 Interest cost 13.2 13.9 0.8 0.8 Expected return on plan assets (11.4) (12.4) - - Amortization of net actuarial loss from earlier periods 4.6 6.6 - 0.1 Amortization of net prior service costs from earlier periods (0.2) - (0.2) (0.2) Net periodic expense $ 20.2 $ 21.9 $ 2.8 $ 2.6 The Company made a contribution of $ 15.6 million to its funded pension plan as well as payments of $ 3.2 million related to its unfunded U.S. DBPPs and $ 0.4 million to its U.S. other retirement plans during the nine months ended September 3 0 , 201 8 . Additionally, the Company anticipates making payments of $ 2.1 million and $ 0.5 million to its unfunded U.S. DBPPs and U.S. other retirement plans, respectively, during the remainder of 2018 .

INDEBTEDNESS

INDEBTEDNESS	9 Months Ended
	Sep. 30, 2018
Indebtedness [Abstract]
INDEBTEDNESS	NOTE 15 . INDEBTEDNESS The following table summarizes total indebtedness: September 30, 2018 Principal Amount Fair Value of Interest Rate Swaps (1) Unamortized (Discount) Premium Unamortized Debt Issuance Costs Carrying Value Notes Payable: 5.50% 2010 Senior Notes, due 2020 $ 500.0 $ (8.3) $ (0.7) $ (0.8) $ 490.2 4.50% 2012 Senior Notes, due 2022 500.0 (3.1) (1.7) (1.5) 493.7 4.875% 2013 Senior Notes, due 2024 500.0 - (1.6) (2.1) 496.3 2.75% 2014 Senior Notes (5-Year), due 2019 450.0 (3.8) (0.1) (0.5) 445.6 5.25% 2014 Senior Notes (30-Year), due 2044 600.0 - 3.3 (5.5) 597.8 1.75% 2015 Senior Notes, due 2027 580.7 - - (3.2) 577.5 2.75% 2017 Senior Notes, due 2021 500.0 (2.6) (1.1) (2.6) 493.7 2.625% 2017 Senior Notes, due 2023 500.0 - (0.9) (3.1) 496.0 3.25% 2017 Senior Notes, due 2028 500.0 - (4.9) (3.8) 491.3 3.25% 2018 Senior Notes, due 2021 300.0 - (0.4) (1.6) 298.0 2017 Term Loan Facility, due 2020 50.0 - - (0.5) 49.5 Commercial Paper 25.0 - (0.1) - 24.9 Total debt $ 5,005.7 $ (17.8) $ (8.2) $ (25.2) $ 4,954.5 Current portion (470.5) Total long-term debt $ 4,484.0 December 31, 2017 Principal Amount Fair Value of Interest Rate Swaps (1) Unamortized (Discount) Premium Unamortized Debt Issuance Costs Carrying Value Notes Payable: 5.50% 2010 Senior Notes, due 2020 $ 500.0 $ - $ (1.0) $ (1.2) $ 497.8 4.50% 2012 Senior Notes, due 2022 500.0 (0.8) (2.0) (1.7) 495.5 4.875% 2013 Senior Notes, due 2024 500.0 - (1.8) (2.4) 495.8 2.75% 2014 Senior Notes (5-Year), due 2019 450.0 (2.2) (0.2) (1.1) 446.5 5.25% 2014 Senior Notes (30-Year), due 2044 600.0 - 3.3 (5.7) 597.6 1.75% 2015 Senior Notes, due 2027 600.4 - - (3.6) 596.8 2.75% 2017 Senior Notes, due 2021 500.0 - (1.3) (3.2) 495.5 2017 Floating Rate Senior Notes, due 2018 300.0 - - (0.5) 299.5 2.625% 2017 Senior Notes, due 2023 500.0 - (1.1) (3.5) 495.4 3.25% 2017 Senior Notes, due 2028 500.0 - (5.2) (3.9) 490.9 2017 Term Loan Facility, due 2020 500.0 - - (0.7) 499.3 Commercial Paper 130.0 - (0.1) - 129.9 Total debt $ 5,580.4 $ (3.0) $ (9.4) $ (27.5) $ 5,540.5 Current portion (429.4) Total long-term debt $ 5,111.1 (1) The Company has entered into interest rate swaps on the 2010 Senior Notes, the 2012 Senior Notes, the 2014 Senior Notes (5-Year) and the 2017 Senior Notes due 2021 which are more fully discussed in Note 9 above. These amounts represent the cumulative amount of fair value hedging adjustments included in the carrying amount of the hedged debt. Term Loan Facility In the second quarter of 2018, the Company repaid $450 million of the 2017 Term Loan Facility. As of September 30, 2018, the Company has $50 million outstanding und er the 2017 Term Loan Facility. Commercial Paper As of September 30, 2018, the Company has CP borrowings outstanding of $25 million with a weighted average maturity date at the time of issuance of 11 days. At September 30, 2018, the weighted average remaining maturity and interest rate on CP outstanding was 5 days and 2.35% respectively. Notes Payable On June 1, 2018, the Company issued $300 million aggregate principal amount of senior unsecured notes in a public offering. The 2018 Senior Notes bear interest at the annual fixed rate of 3.250% and mature on June 7, 2021. Interest on the notes will be due semi-annually on June 7 and December 7 of each year, commencing December 7, 2018. The Company may redeem, in whole or in part, the notes at any time, at a price equal to the greater of (i) 100% of the pri ncipal amount being prepaid, plus accrued and unpaid interest, and (ii) the make-whole redemption price set forth in the notes, plus accrued and unpaid interest. Notwithstanding the preceding sentence, the Company may redeem all or a portion of the notes a t its option at any time on or after May 7, 2021 (one month prior to their maturity), at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. Additionally, at the option of the holders of the notes, the Company may be required to purchase all or a portion of the notes upon the occurrence of a Change of Control Triggering Event (as defined in the Indenture) at a price equal to 101% of the princ ipal amount thereof, plus accrued and unpaid interes t to the date of purchase. The i ndenture contains covenants that limit the ability of the Company and certain of its subsidiaries to, among other things, incur or create liens and enter into sale and leas eback transactions. In addition, the i ndenture contains a covenant that limits the ability of the Company to consolidate or merge with another entity or to sell all or substantially all of its assets to another entity. The i ndenture contains customary defa ult provisions. In addition, an event of default will occur if the Company or certain of its subsidiaries fail to pay the principal of any Indebtedness (as defined in the Indenture) when due at maturity in an aggregate amount of $50 million or more, or a d efault occurs that results in the acceleration of the maturity of the Company’s o r certain of its subsidiaries’ i ndebtedness in an aggregate amount of $50 million or more. Upon the occurrence and during the continuation of an event of default under the i nd enture, the notes may become immediately due and payable either automatically or by the vote of the holders of more than 25% of the aggregate principal amount of all of the notes then outstanding . In the third quarter of 2018, the Company repaid the 2017 F loating Rate Senior Note s of $300 million . At September 30, 2018, the Company was in compliance with all covenants contained within all of its debt agreements. All the debt agreements contain cross default provisions which state that default under one of t he aforementioned debt instruments could in turn permit lenders under other debt instruments to declare borrowings outstanding under those instruments to be immediately due and payable. As of September 30, 2018, there were no such cross defaults . The repay ment schedule for the Company’s borrowings is as follows: Year Ending December 31, 2010 Senior Notes due 2020 2012 Senior Notes due 2022 2013 Senior Notes due 2024 2014 Senior Notes (5-year) due 2019 2014 Senior Notes (30-year) due 2044 2015 Senior Notes due 2027 2017 Term Loan Facility due 2020 2017 Senior Notes due 2021 2017 Notes due 2023 2017 Notes due 2028 2018 Notes due 2021 Commercial Paper Total 2018 (after September 30,) $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ 25.0 $ 25.0 2019 - - - 450.0 - - - - - - - - 450.0 2020 500.0 - - - - - 50.0 - - - - - 550.0 2021 - - - - - - - 500.0 - - 300.0 - 800.0 2022 - 500.0 - - - - - - - - - - 500.0 Thereafter - - 500.0 - 600.0 580.7 - - 500.0 500.0 - - 2,680.7 Total $ 500.0 $ 500.0 $ 500.0 $ 450.0 $ 600.0 $ 580.7 $ 50.0 $ 500.0 $ 500.0 $ 500.0 $ 300.0 $ 25.0 $ 5,005.7 Interest expense, net The following table summarizes the components of interest as presented in the consolidated statements of operations: Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Income $ 4.1 $ 4.3 $ 10.7 $ 13.0 Expense on borrowings (46.4) (48.8) (147.1) (139.9) UTPs and other tax related liabilities (9.6) (3.9) (10.6) (9.4) Net periodic pension costs - interest component (1) (4.9) (5.0) (14.5) (14.7) Capitalized 0.4 0.3 1.0 0.8 Total $ (56.4) $ (53.1) $ (160.5) $ (150.2) (1) The Company adopted ASU No. 2017-07 in the first quarter of 2018, whereby all components of pension expense except for the service cost component are required to be presented in other non-operating income. The service cost component continues to be reported as an operating expense. The following table shows the cash paid for interest: Nine months ended September 30, 2018 2017 Interest paid $ 169.7 $ 136.2 The Company’s debt is recorded at its carrying amount, which represents the issuance amount plus or minus any issuance premium or discount, except for the 2010 Senior Notes, the 2014 Senior Notes (5-Year), the 2012 Senior Notes and the 2017 Senior Notes d ue 2021 which are recorded at the carrying amount adjusted for the fair value of an interest rate swap used to hedge the fair value of the note. The fair value and carrying value of the Company’s debt (excluding Commercial Paper) as of September 30, 2018 and December 31, 2017 are as follows : September 30, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value 5.50% 2010 Senior Notes, due 2020 $ 490.2 $ 519.7 $ 497.8 $ 537.9 4.50% 2012 Senior Notes, due 2022 493.7 514.8 495.5 535.6 4.875% 2013 Senior Notes, due 2024 496.3 522.2 495.8 547.8 2.75% 2014 Senior Notes (5-Year), due 2019 445.6 449.4 446.5 452.8 5.25% 2014 Senior Notes (30-Year), due 2044 597.8 667.1 597.6 722.4 1.75% 2015 Senior Notes, due 2027 577.5 594.8 596.8 617.7 2.75% 2017 Senior Notes, due 2021 493.7 488.6 495.5 500.0 2017 Floating Rate Senior Notes, due 2018 - - 299.5 300.2 2.625% 2017 Senior Notes, due 2023 496.0 478.5 495.4 494.8 3.25% 2017 Senior Notes, due 2028 491.3 469.1 490.9 493.6 2017 Term Loan Facility, due 2020 49.5 49.5 499.3 499.3 3.25% 2018 Senior Notes, due 2021 298.0 298.7 - - Total $ 4,929.6 $ 5,052.4 $ 5,410.6 $ 5,702.1 The fair value of the Company’s long-term debt is estimated based on quoted market prices for similar instruments . Accordingly, the inputs used to estimate the fair value of the Company’s long-term debt are classified as Level 2 inputs within the fair value hierarchy.

CONTINGENCIES

CONTINGENCIES	9 Months Ended
	Sep. 30, 2018
Contingencies [Abstract]
CONTINGENCIES	NOTE 16 . CONTINGENCIES Given the nature of their activities, Moody’s and its subsidiaries are subject to legal and tax proceedings, governmental, regulatory and legislative investigations, subpoenas and other inquiries, and claims and litigation by governmental and private parties that are based on ratings assigned by MIS or that are otherwise incidental to the Company’s business. Moody’s and MIS also are subject to periodic reviews, inspections, examinations and investigations by regulators in the U.S. and other jurisdictio ns, any of which may result in claims, legal proceedings, assessments, fines, penalties or restrictions on business activities. Moody’s also is subject to ongoing tax audits as addressed in Note 5 to the financial statements. In May 2013, the Company and f ive subsidiaries (collectively, the “Company Defendants”) were served with a qui tam complaint filed by a former employee (“Plaintiff”) in New York Supreme Court (the “Court”) on behalf of New York State (the “State”) and New York City (the “City”) asserti ng purported claims under the New York False Claims Act (“NYFCA”). Both the State and the City were given an opportunity to intervene as plaintiffs in the action but declined to do so. In August 2013, Plaintiff filed an Amended Complaint adding Marsh & M cLennan Companies, Inc. as a defendant. Plaintiff’s central allegation against the Company Defendants is that their treatment of the Company’s wholly-owned captive insurance subsidiary, Moody’s Assurance Company, Inc. (“MAC”), in their State and City tax filings between 2002 and 2014 was contrary to the State and City tax codes. Plaintiff also asserts a cause of action for retaliation under the NYFCA and alleges that his employment was improperly terminated after he reported his concerns regarding MAC’s t ax treatment internally. Plaintiff alleges that the Company underpaid State and City taxes by more than $120 million (which the Company believes is unsupported as a matter of fact and law), and requests statutory damages of triple that amount, as well as unspecified damages related to the retaliation claim. In December 2016, the Court issued a decision largely denying the Company Defendants’ motion to dismiss. The Company Defendants appealed, and in August 2018, the Appellate Division of the New York Sup reme Court upheld the Court’s decision. Discovery is ongoing and, absent earlier disposition, the Company expects the case to go to trial no earlier than late 2019. The Company is unable to estimate a range of loss, and is contesting Plaintiff’s claims, w hich it believes are meritless. Management periodically assesses the Company’s liabilities and contingencies in connection with these matters based upon the latest information available. For claims, litigation and proceedings and governmental investigati ons and inquiries not related to income taxes, the Company records liabilities in the consolidated financial statements when it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated and periodically adjusts these as appropriate. When the reasonable estimate of the loss is within a range of amounts, the minimum amount of the range is accrued unless some higher amount within the range is a better estimate than another amount within the range. In instances when a loss is reasonably possible but uncertainties exist related to the probable outcome and/or the amount or range of loss, management does not record a liability but discloses the contingency if material. As additional information becomes available, the Com pany adjusts its assessments and estimates of such matters accordingly. Moody’s also discloses material pending legal proceedings pursuant to SEC rules and other pending matters as it may determine to be appropriate. In view of the inherent difficulty o f assessing the potential outcome of legal proceedings, governmental, regulatory and legislative investigations and inquiries, claims and litigation and similar matters and contingencies, particularly when the claimants seek large or indeterminate damages or assert novel legal theories or the matters involve a large number of parties, the Company often cannot predict what the eventual outcome of the pending matters will be or the timing of any resolution of such matters. The Company also may be unable to pr edict the impact (if any) that any such matters may have on how its business is conducted, on its competitive position or on its financial position, results of operations or cash flows. As the process to resolve any pending matters progresses, management w ill continue to review the latest information available and assess its ability to predict the outcome of such matters and the effects, if any, on its operations and financial condition and to accrue for and disclose such matters as and when required. Howev er, because such matters are inherently unpredictable and unfavorable developments or resolutions can occur, the ultimate outcome of such matters, including the amount of any loss, may differ from those estimates.

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2018
Segment Information [Abstract]
SEGMENT INFORMATION	NOTE 17 . SEGMENT INFORMATION The Company is organized into two operating segments: MIS and MA and accordingly, the Company reports in two reportable segments: MIS and MA. The MIS segment consists of five LOBs. The CFG, SFG, FIG and PPIF LOBs generate revenue principally from fees for the assignment and ongoing monitoring of credit ratings on debt obligations and the entities that issue such obligations in markets worldwide. The MIS Other LOB primarily consists of financial instruments pricing services in the Asia-Pacific region as well as ICRA non-ratings revenue. The MA segment develops a wide range of products and services that support the risk management activities of institutional participants in global financial markets. The MA segment con sists of three LOBs - RD&A, ERS and PS. In August 2017, a subsidiary of the Company acquired Yellow Maple I B.V., an indirect parent of Bureau van Dijk. Bureau van Dijk is part of the MA reportable segment and its revenue is included in the RD&A LOB. Re fer to Note 8 for further discussion on the acquisition . Revenue for MIS and expenses for MA include an intersegment royalty charged to MA for the rights to use and distribute content, data and products developed by MIS. The royalty rate charged by MIS app roximates the fair value of the aforementioned content, data and products and is generally based on comparable market transactions. Also, revenue for MA and expenses for MIS include an intersegment fee charged to MIS from MA for certain MA products and ser vices utilized in MIS’s ratings process. These fees charged by MA are generally equal to the costs incurred by MA to produce these products and services. Additionally, overhead costs and corporate expenses of the Company that exclusively benefit only one s egment are fully charged to that segment. Overhead costs and corporate expenses of the Company that benefit both segments are allocated to each segment based on a revenue-split methodology. Accordingly, a reportable segment’s share of these costs will incr ease as its proportion of revenue relative to Moody’s total revenue increases. Overhead expenses include costs such as rent and occupancy, information technology and support staff such as finance, human reso urces and legal . “Eliminations” in the table belo w represent intersegment revenue/expense. Moody’s does not report the Company’s assets by reportable segment, as this metric is not used by the chief operating decision maker to allocate resources to the segments. Consequently, it is not practical to show assets by reportable segment. Financial Information by Segment The table below shows revenue, Adjusted Operating Income and operating income by reportable segment. Adjusted Operating Income is a financial metric utilized by the Company’s chief operating decision maker to assess the profitability of each reportable segment. Refer to Note 3 for further details on the components of the Company’s revenue. Three Months Ended September 30, 2018 2017 MIS MA Eliminations Consolidated MIS* MA* Eliminations Consolidated* Revenue $ 676.4 $ 438.6 $ (34.2) $ 1,080.8 $ 723.2 $ 372.8 $ (33.1) $ 1,062.9 Operating, SG&A 287.7 313.1 (34.2) 566.6 317.3 277.1 (33.1) 561.3 Adjusted Operating Income 388.7 125.5 - 514.2 405.9 95.7 - 501.6 Less: Depreciation and amortization 15.8 30.3 - 46.1 18.6 24.4 - 43.0 Acquisition-Related Expenses - 1.3 - 1.3 - 10.1 - 10.1 Operating income $ 372.9 $ 93.9 $ - $ 466.8 $ 387.3 $ 61.2 $ - $ 448.5 Nine Months Ended September 30, 2018 2017 MIS MA Eliminations Consolidated MIS* MA* Eliminations Consolidated* Revenue $ 2,209.0 $ 1,275.6 $ (102.0) $ 3,382.6 $ 2,131.1 $ 1,001.1 $ (93.6) $ 3,038.6 Operating, SG&A 901.7 943.6 (102.0) 1,743.3 893.2 758.6 (93.6) 1,558.2 Adjusted Operating Income 1,307.3 332.0 - 1,639.3 1,237.9 242.5 - 1,480.4 Less: Depreciation and amortization 49.3 94.3 - 143.6 56.4 52.0 - 108.4 Acquisition-Related Expenses - 4.1 - 4.1 - 16.7 - 16.7 Operating income $ 1,258.0 $ 233.6 $ - $ 1,491.6 $ 1,181.5 $ 173.8 $ - $ 1,355.3 *Pursuant to the adoption of a new accounting standard relating to pension accounting as more fully discussed in Note 1, only the service cost component of net periodic pension expense will be classified within operating and SG&A expenses with the remaining components being classified as non-operating expenses. Prior period segment results have been restated to reflect this reclassification. Accordingly, operating and SG&A expenses for MIS and MA for the three months ended September 30, 2017 were reduced by $1.9 million and $1.2 million. For the nine months ended September 30, 2017, operating and SG&A expenses for MIS and MA were reduced by $5.7 million and $3.3 million, respectively. CONSOLIDATED REVENUE INFORMATION BY GEOGRAPHIC AREA Consolidated Revenue Information by Geographic Area: Three Months Ended September 30, Nine months ended September 30, 2018 2017 2018 2017 United States $ 559.6 $ 588.4 $ 1,782.7 $ 1,734.0 International: EMEA 344.5 291.0 1,047.9 779.3 Asia-Pacific 123.0 118.6 366.9 336.0 Americas 53.7 64.9 185.1 189.3 Total International 521.2 474.5 1,599.9 1,304.6 Total $ 1,080.8 $ 1,062.9 $ 3,382.6 $ 3,038.6

RECENTLY ISSUED ACCOUNTING STAN

RECENTLY ISSUED ACCOUNTING STANDARDS	9 Months Ended
	Sep. 30, 2018
Recently Issued Accounting Standards [Abstract]
RECENTLY ISSUED ACCOUNTING STANDARDS	NOTE 18 . RECENTLY ISSUED ACCOUNTING STANDARDS In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” requiring lessees to recognize a right-of-use asset and lease liability for all leases with terms of more than 12 months. Recognition, measurement and presentation of expenses and cash flows will depend on classification as either a finance or operating lease. During July 2018, the FASB issued additional updates to the new lease accounting standard. ASU No. 2018-10, “Codification Improvements to Topic 842, Leases” clarifies certain aspects of the new lease accounting standard. In addition, ASU No. 2018-11, “Leases (Topic 842), Targeted Improvements” provides companies with the option to apply the provisions of the new lease accounting standard on the date of adoption (effective date of January 1, 2019 for Moody’s), and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, without adjusting the comparative periods presented, as initially required. The Company will adopt the new lease accounting standard as of January 1, 2019 and has elected to apply the provisions of the standard on the date of adoption. Accordingly, the Company will not restate prior year comparative periods for the impact of the new standard. The Company inte nds to elect the package of practical expedients permitted under the transition guidance within the new lease accounting standard, which permits the Company not to reassess the following for any expired or existing contracts: i) whether any contracts conta in leases; ii) lease classification (i.e. operating lease or finance/capital lease); and iii) initial direct costs. At September 30, 2018, the Company continues to assess and document key changes to its accounting policies relating to the adoption of the n ew lease accounting standard. Additionally, the Company is assessing the impact that the standard will have on its processes and internal controls. Furthermore, the Company is in the process of implementing a software solution which support s the ac countin g under the new lease accounting standard. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments”. The amendments in this ASU require the use of an “expected c redit loss” impairment model for most financial assets reported at amortized cost which will require entities to estimate expected credit losses over the lifetime of the instrument. This may result in the earlier recognition of allowances for losses. For a vailable-for-sale debt securities with unrealized losses, an allowance for credit losses will be recognized as a contra account to the amortized cost carrying value of the asset rather than a direct reduction to the carrying value, with changes in the allo wance impacting earnings. This ASU is effective for annual and interim reporting periods beginning after December 15, 2019, with early adoption permitted in annual and interim reporting periods beginning after December 15, 2018. Entities will apply the sta ndard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first effective reporting period. The Company is currently evaluating the impact of this ASU on its financial statements. Currently, the Company believes t hat the most notable impact of this ASU will relate to its processes around the assessment of the adequacy of its allowance for doubtful accounts on accounts receivable. In February 2018, FASB issued ASU No. 2018-02, “Reclassification of Certain Tax Effect s from Accumulated Other Comprehensive Income”. Under current GAAP, adjustments to deferred tax assets and liabilities related to a change in tax laws or rates are included in income from continuing operations, even in situations where the related items we re originally recognized in OCI (commonly referred to as a “stranded tax effect”). The provisions of this ASU permit the reclassification of the stranded tax effect related to the Tax Act from AOCI to retained earnings. This ASU is effective for all entiti es for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with early adoption permitted. Adoption of this ASU is to be applied either in the period of adoption or retrospectively to each period in which the effec t of the Tax Act were recognized. The Company is currently in the process of quantifying the amount of the reclassification from AOCI to retained earnings relating to the aforementioned stranded tax effect of the Tax Act . In June 2018, the FASB issued ASU No. 2018-07, “ Compensation —Stock Compensation (Topic 718): Improve ments to Nonemployee Share-Based Payment Accounting” , which simplifies the accounting for nonemployee share-based payment transactions. The amendments specify that ASC Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. The ASU is effective f or all entities for fiscal years beginning after December 1 5, 201 9 , and interim periods within those fiscal years, with early adoption permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its consolidated financial statements. In August 2018, the FASB issued AS U No. 2018-15, “ Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40) : Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract”, which requires implementation costs incurred by cu stomers in cloud computing arrangements (i.e., hosting arrangements) to be capitalized under the same premises of authoritative guidance for internal-use software, and deferred over the non - cancellable term of the cloud computing arrangements plus any opti on renewal periods that are reasonably certain to be exercised by the customer or for which the exercise is controlled by the service provider. The ASU is effective for all entities for fiscal years beginning after December 15, 2019, and interim periods wi thin those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of this ASU on its financial statements and currently does not expect that it will h ave a significant impact on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, “ Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20) : Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans ” . This ASU eliminates requirements for certain disclosures and requires additional disclosures under defined benefit pension plans and ot her postretirement plans. The ASU is effective for all entities for fiscal years beginning after December 15, 20 20 on a retrospective basis to all periods presented , with early adoption permitted. The Company is currently evaluating the impact of this ASU on its financial statements .

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 19 . SUBSEQUENT EVENT S On October 22, 2018 , the Board approved the declaration of a quarterly dividend of $0.44 per share of Moody’s common stock, payable on December 12, 2018 to shareholders of record at the close of business on November 21, 2018 . On October 15, 2018, the Company completed the acquisition of Reis, Inc. , a provider of c ommercial real estate market information and analytical tools to real estate professionals for approximately $278 million . T he acquisition further expands Moody's An alytics’ network of data and analytics providers in the commercial real estate space . Due to the close proximity of the completion of the acquisition to the filing of this Form 10-Q, the Company is unable to provide a preliminary purchase price allocation of the fair value of the assets purchased and liabilities assumed in the transaction. The Company will disclose a preliminary purchase price allocation in its Form 10-K for the year ended December 31, 2018. On October 26, 2018, the Company approved a restructuring program (the “Program”) that the Company estimates will result in annualized savings of approximately $30 to $40 million a year commencing in 2019. The Program is estimated to result in total pre-tax charges of $45 to $60 million, of which $30 to $40 million are expected to be recorded in the fourth quarter 2018. The Program is e xpected to be substantially completed by June 30, 2019. The Program includes relocation of certain functions from high-cost to lower-cost jurisdictions, a reduction of staff, including from recent acquisitions and pursuant to a review of the business criti cality of certain positions, and the rationalization and exit of certain real estate leases due to consolidation of various business activities. The exit from certain leased office space is anticipated to begin in the fourth quarter of 2018 and to entai l approximately $20 to $25 million of the charges to either terminate or sublease the affected real estate leases. The Program is anticipated also to represent approximately $25 to $35 million of personnel-related restructuring charges, an amount that incl udes severance and related costs primarily determined under the Company’s existing severance plans. The Company expects that a majority of the charge relating to severance and related costs will be recognized in the fourth quarter of 2018. Cash outlays a ssociated with the Program are anticipated to be approximately $25 to $35 million, the majority of which will be paid in 2019.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2018
Summary of Significant Accounting Policies [Abstract]
Revenue Recognition and Costs to Obtain or Fulfill a Contract with a Customer	Revenue Recognition and Costs to Obtain or Fulfill a Contract with a Customer Revenue recognition: Revenue is recognized when control of promised goods or services is transferred to the customer, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. When contracts with c ustomers contain multiple performance obligations, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to each distinct performance obligation on a relative SSP basis. The Company determines the SSP by using the price charged for a deliverable when sold separately or uses management’s best estimate of SSP for goods or services not sold separately based on the maximum number of observable data points, including: internal factors rele vant to its pricing practices such as costs and margin objectives; standalone sales prices of similar products; percentage of the fee charged for a primary product or service relative to a related product or service; and customer segment and geography. Add itional consideration is also given to market conditions such as competitor pricing strategies and market trends. Sales, usage-based, value added and other taxes are excluded from revenues. MIS Revenue In the MIS segment, revenue arrangements are generally comprised of two distinct performance obligations, an initial rating and the related monitoring service. Revenue attributed to initial ratings of issued securities is generally recognized when the rating is delivered to the issuer. Revenue attributed to m onitoring of issuers or issued securities is recognized ratably over the period in which the monitoring is performed, generally one year. In the case of certain structured finance products, primarily CMBS, issuers can elect to pay all of the annual monitor ing fees upfront. These fees are deferred and recognized over the future monitoring periods based on the expected lives of the rated securities. MIS arrangements generally have standard contractual terms for which the stated payments are due at conclusion of the ratings process for initial ratings and either upfront or in arrears for monitoring services; and are signed by customers either on a per issue basis or at the beginning of the relationship with the customer. However, customer fee arrangements may b e adjusted for which the Company accounts for as variable consideration at inception using the expected value method based on analysis of similar contracts in the same line of business , which is constrained based on the Company’s assessment of the realizat ion of the adjustment amount. The Company allocates the transaction price within arrangements that include both the initial rating and the related monitoring service based upon the relative SSP of each service. The Company generally uses management’s best estimate based on observable pricing points in determining SSP for its initial ratings as the Company rarely provides initial ratings separately without providing related monitoring services. The SSP for monitoring fees in these arrangements are generally based upon directly observable selling prices where the monitoring service is sold separately. MA Revenue In the MA segment, products and services offered by the Company include hosted research and data subscriptions, installed software subscriptions, perp etual installed software licenses and related maintenance, or PCS, and professional services. Subscription and PCS contracts are generally invoiced in advance of the contractual coverage period, which is principally one year, but can range from 3-5 years; while perpetual software licenses are generally invoiced upon delivery and professional services are invoiced as those services are provided. Payment terms and conditions vary by contract type, but primarily include a requirement of payment within 30 to 60 days. Revenue from research, data and other hosted subscriptions is recognized ratably over the related subscription period. A large portion of these services are invoiced in the months of November, December and January. Revenue from the sale of a softwar e license, when considered distinct from the related software implementation services, is generally recognized at the time the product master or first copy is delivered or transferred to the customer. However, in instances where the software license (perpe tual or subscription) and related implementation services are considered to be one combined performance obligation, revenue is recognized on a percentage-of-completion basis (input method) as implementation services are performed over time, which is consis tent with the pattern of recognition for the software implementation services if considered to be a separate distinct performance obligation. The Company exercises judgment in determining the level of integration and interdependency between the promise to grant the software license and the promise to deliver the related implementation services. This determination influences whether the software license is considered distinct and accounted for separately, or not distinct and accounted for together with the i mplementation services and recognized over time. PCS is generally recognized ratably over the contractual period commencing when the software license is fully delivered. Revenue from installed software subscriptions, which includes PCS, is bifurcated into a software license performance obligation and a PCS performance obligation, which follow the patterns of recognition described above. For implementation services and other service projects within the ERS and ESA LOBs for which fees are fixed, the Company d etermined progress towards completion is most accurately measured on a percentage-of-completion basis (input method) as this approach utilizes the most directly observable data points and is therefore used to recognize the related revenue. For implementati on services where price varies based on time expended, a time-based measure of progress towards completion of the performance obligation is utilized. Revenue from professional services rendered within the PS LOB is generally recognized as the services are performed over time . Products and services offered within the MA segment are sold either stand-alone or together in various combinations. In instances where an arrangement contains multiple performance obligations, the Company accounts for the individual p erformance obligations separately if they are considered distinct. Revenue is generally allocated to all performance obligations based upon the relative SSP at contract inception. Judgment is often required to determine the SSP for each distinct performanc e obligation. Revenue is recognized for each performance obligation based upon the conditions for revenue recognition noted above. In the MA segment, customers usually pay a fixed fee for the products and services based on signed contracts. However, accounting for variable consideration is applied mainly for: i) estimates for cancellation rights and price concessions and ii) T&M based services. The Company estimates the variable consideration associated with cancellation rights and price concessions b ased on the expected amount to be provided to customers and reduces the amount of revenue to be recognized. T&M based contracts represent about half of MA’s service projects within the ERS and ESA LOBs. The Company provides agreed upon services at a contra cted daily or hourly rate. The commitment represents a series of goods and services that are substantially the same and have the same pattern of transfer to the customer. As such, if T&M services are sold with other MA products, the Company allocates the v ariable consideration entirely to the T&M performance obligation if the services are sold at standard pricing or at a similar discount level compared to other performance obligations in the same revenue contract. If these criteria are not met, the Company estimates variable consideration for each performance obligation upfront. Each form of variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal of any incremental revenue will not occur. Costs to Obtain or Fulfill a Contract with a Customer: Costs incurred to obtain customer contracts, such as sales commissions, are deferred and recorded within other current assets and other assets when such costs are determined to be incremental to obtaining a contract, would not have been incurred otherwise and the Company expects to recover those costs. These costs are amortized to expense consistent with the recognition pattern of the related revenue over time . Depending on the line of business to which the contract relates, this may be based upon the average economic life of the products sold or average period for which services are provided, inclusive of anticipated contract renewals. Determining the estimated economic life of the products sold r equires judgment with respect to anticipated future technological changes. The Company had a balance of $ 93.3 million in such deferred costs as of September 30, 2018 and recognized $ 8.0 million and $24.7 million of relat ed amortization during the three and nine -month period s ended September 30, 2018 , respectively, which is included within SG&A expenses in the consolidated statement of operations. Costs incurred to obtain customer contracts are only in the MA segment. Costs incurred to fulfill customer contracts, are deferred and recorded within other current assets and other assets when such costs relate directly to a contract , generate or enhance resources of the Company that will be used in satisfying performance obligations in the future an d the Company expects to recover those costs. The Company capitalizes work-in-process costs for in-progress MIS ratings, which is recognized consistent with the rendering of the related services to the customers, as ratings are issued. The Company had a ba lance of $10.6 million in such deferred costs as of September 30, 2018 and recognized $ 10.3 million and $29.8 million of amortization of the costs during the three and nine-month periods ended September 30, 2018, respectively, which is included within operating expenses in the consolidated statement of operations. In addition, within the MA segment, the Company capitalizes royalty costs related to third-party information data providers associated with hosted company information and business intelligence products. These costs are amortized to expense consistent with the recognition pattern of the related revenue over time. The Company had a balance of $ 24.8 million in such deferred costs as of September 30, 2018 and recognized $12.9 million and $41.2 million of relat ed a mortization during the three and nine -month period s ended September 30, 2018 , respectively, which is included within operating expenses in the consolidated statement of operations.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments include cash, cash equivalents, trade receivables and payables, all of which are short-term in nature and, accordingly, approximate fair value. Additionally, the Company invests in certain short-term investments consisting primarily of certificates of depo sit that are carried at cost, which approximates fair value due to their short-term maturities. The Company also has certain investments in closed-ended and open-ended mutual funds in India which are accounted for as equity securities with readily determin able fair values under ASC Topic 321. Beginning in the first quarter of 2018, the Company will measure these investments at fair value with both realized gains and losses and unrealized holding gains and losses for these investments included in net income. Prior to January 1, 2018, the investments in closed-ended and open-ended mutual funds in India were designated as ‘available for sale’ under Topic 320 of the ASC. Accordingly, unrealized gains and losses on these investments were recorded to other compreh ensive income and were reclassified out of accumulated other comprehensive income to the statement of operations when the investment matured or was sold using a specific identification method. Also, the Company uses derivative instruments to manage certain financial exposures that occur in the normal course of business. These derivative instruments are carried at fair value on the Company’s consolidated balance sheets. Fair value is defined by the ASC as the price that would be received from selling an asse t or paid to transfer a liability (i.e., an exit price) in an orderly transaction between market participants at the measurement date. The determination of this fair value is based on the principal or most advantageous market in which the Company could com mence transactions and considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions and risk of nonperformance. Also, determination of fair value assumes that market participants will consider the highest and best use of the asset. The ASC establishes a fair value hierarchy whereby the inputs contained in valuation techniques used to measure fair value are categorized into three broad levels as follows: Level 1: quoted market pric es in active markets that the reporting entity has the ability to access at the date of the fair value measurement; Level 2: inputs other than quoted market prices described in Level 1 that are observable for the asset or liability, either directly or indi rectly, such as quoted prices in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active or other inputs that are observable or can be corroborated by observable market d ata for substantially the full term of the assets or liabilities; Level 3: unobservable inputs that are supported by little or no market activity and that are significant to the fair value measurement of the assets or liabilities.
Derivatives and Hedging Policy	Derivative Instruments an d Hedging Activities Based on the Company’s risk management policy, from time to time the Company may use derivative financial instruments to reduce exposure to changes in foreign exchange rates and interest rates. The Company does not enter into derivati ve financial instruments for speculative purposes. All derivative financial instruments are recorded on the balance sheet at their respective fair values. The changes in the value of derivatives that qualify as fair value hedges are recorded in the same in come statement line item in earnings in which the corresponding adjustment to the carrying value of the hedged item is presented. The entire change in the fair value of derivatives that qualify as cash flow hedges is recorded to OCI and such amounts are re classified from AOCI to the same income statement line in earnings in the same period or periods during which the hedged transaction affects income. Effective with the Company early adoption of ASC 2017-12, the Company changed the method by which it assess es effectiveness for net investment hedges from the forward-method to the spot-method. The Company considers the spot-method an improved method of assessing hedge effectiveness, as spot rate changes relating to the hedging instrument’s notional amount per fectly offset the currency translation adjustment on the hedged net investment in the Company’s foreign subsidiaries. The entire change in the fair value of derivatives that qualify as net investment hedges is initially recorded to OCI. Those changes in fa ir value attributable to components included in the assessment of hedge effectiveness in a net investment hedge are recorded in the currency translation adjustment component of OCI and remain in AOCI until the period in which the hedged item affects earnin gs. Those changes in fair value attributable to components excluded from the assessment of hedge effectiveness in a net investment hedge are recorded to OCI and amortized to earnings using a systematic and rational method over the duration of the hedge. An y changes in the fair value of derivatives that the Company does not designate as hedging instruments under Topic 815 of the ASC are recorded in the consolidated statements of operations in the period in which they occur. Refer to Note 9 for further inform ation regarding the Company’s derivative financial instruments and hedging activities .

DESCRIPTION OF BUSINESS AND B_2

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule of Cumulative Adjustment to Retained earnings due to prospective adoption of new revenue guidance	Transition adjustment Benefit to / (reduction of) January 1, 2018 Retained Earnings Corresponding Balance Sheet Line Item Recognition of MA deferred revenue / increase in MA unbilled receivables (1) $108 million Deferred revenue, Non-current portion of deferred revenue, Accounts receivable, Other assets Increase to capitalized MA sales commissions (2) $78 million Other current assets, Other assets, Accounts payable and accrued liabilities Capitalization of work-in-process for in-progress ratings $9 million Other current assets Net impact of all other adjustments $4 million Various Net increase in tax liability on the above ($43 million) Deferred tax liabilities, net Total post-tax adjustment $156 million (1) Represents deferred revenue as of December 31, 2017 as well as amounts then unbilled that would have been recognized as revenue in 2017 or earlier if the New Revenue Accounting Standard was then in effect. These amounts will not be recognized as revenue in future statements of operations. Conversely, revenue will be recorded to the Company's statement of operations in 2018 under the New Revenue Accounting Standard, which otherwise would have been recognized in periods subsequent to 2018 if accounted for under ASC Topic 605. (2) Represents sales commissions that would have been capitalized as of December 31, 2017 if the New Revenue Accounting Standard was then in effect, but had previously been expensed by the Company under the previous accounting guidance. These sales commissions, as well as sales commissions incurred in 2018 related to new sales and renewals, will be amortized to expense in the statements of operations beginning in 2018 over an extended period generally based upon the average economic life of the products sold or over the period in which implementation and advisory services will be provided.
New Revenue Accounting Standard [Member] | Balance Sheets [Member]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	As Reported September 30, 2018 Under previous accounting guidance September 30, 2018 Effect of Change Higher/(Lower) ASSETS Current assets: Cash and cash equivalents $ 1,034.8 $ 1,034.8 $ - Short-term investments 110.7 110.7 - Accounts receivable, net of allowances 1,131.8 1,093.4 38.4 Other current assets 238.9 222.5 16.4 Total current assets: 2,516.2 2,461.4 54.8 Property and equipment, net 311.1 311.1 - Goodwill 3,661.3 3,661.3 - Intangible assets, net 1,517.6 1,517.6 - Deferred tax assets, net 189.3 189.3 - Other assets 243.6 172.6 71.0 Total assets $ 8,439.1 $ 8,313.3 $ 125.8 LIABILITIES, NONCONTROLLING INTERESTS AND SHAREHOLDERS' EQUITY Accounts payable and accrued liabilities $ 581.6 $ 581.4 $ 0.2 Commercial paper 24.9 24.9 - Current portion of long-term debt 445.6 445.6 - Deferred revenue 771.5 836.5 (65.0) Total current liabilities 1,823.6 1,888.4 (64.8) Non-current portion of deferred revenue 123.9 130.1 (6.2) Long-term debt 4,484.0 4,484.0 - Deferred tax liabilities, net 354.8 330.8 24.0 Unrecognized tax benefits 471.8 471.8 - Other liabilities 574.9 574.8 0.1 Total liabilities 7,833.0 7,879.9 (46.9) Shareholders' equity: Common stock 3.4 3.4 - Capital surplus 569.7 569.7 - Retained earnings 8,429.1 8,256.4 172.7 Treasury stock (8,260.1) (8,260.1) - Accumulated other comprehensive loss (342.0) (342.0) - Total Moody's shareholders' equity 400.1 227.4 172.7 Noncontrolling interests 206.0 206.0 - Total shareholders' equity 606.1 433.4 172.7 Total liabilities, noncontrolling interests and shareholders' equity $ 8,439.1 $ 8,313.3 $ 125.8
New Revenue Accounting Standard [Member] | Income Statement [Member]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	For the Three Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) Revenue $ 1,080.8 $ 1,072.4 $ 8.4 Expenses Operating 306.3 306.6 (0.3) Selling, general and administrative 260.3 263.4 (3.1) Depreciation and amortization 46.1 46.1 - Acquisition-related expenses 1.3 1.3 - Total expenses 614.0 617.4 (3.4) Operating income 466.8 455.0 11.8 Non-operating (expense) income, net Interest expense, net (56.4) (56.4) - Other non-operating income, net 2.4 2.4 - Total non-operating (expense) income, net (54.0) (54.0) - Income before provision for income taxes 412.8 401.0 11.8 Provision for income taxes 100.8 98.4 2.4 Net income 312.0 302.6 9.4 Less: Net income attributable to noncontrolling interests 1.8 1.8 - Net income attributable to Moody's $ 310.2 $ 300.8 $ 9.4 Earnings per share Basic $ 1.62 $ 1.57 $ 0.05 Diluted $ 1.59 $ 1.55 $ 0.04 Weighted average shares outstanding Basic 191.8 191.8 Diluted 194.5 194.5 For the Nine Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) Revenue $ 3,382.6 $ 3,368.7 $ 13.9 Expenses Operating 941.4 942.8 (1.4) Selling, general and administrative 801.9 807.4 (5.5) Depreciation and amortization 143.6 143.6 - Acquisition-related expenses 4.1 4.1 - Total expenses 1,891.0 1,897.9 (6.9) Operating income 1,491.6 1,470.8 20.8 Non-operating (expense) income, net Interest expense, net (160.5) (160.5) - Other non-operating income, net 18.3 18.3 - Total non-operating (expense) income, net (142.2) (142.2) - Income before provision for income taxes 1,349.4 1,328.6 20.8 Provision for income taxes 282.7 277.6 5.1 Net income 1,066.7 1,051.0 15.7 Less: Net income attributable to noncontrolling interests 7.4 7.4 - Net income attributable to Moody's $ 1,059.3 $ 1,043.6 $ 15.7 Earnings per share Basic $ 5.53 $ 5.44 $ 0.09 Diluted $ 5.45 $ 5.37 $ 0.08 Weighted average shares outstanding Basic 191.7 191.7 Diluted 194.4 194.4
New Revenue Accounting Standard [Member] | Cash Flow [Member]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	For the Nine Months Ended September 30, 2018 As Reported Under previous accounting guidance Effect of Change Cash flows from operating activities Net income $ 1,066.7 $ 1,051.0 $ 15.7 Reconciliation of net income to net cash provided by operating activities: Depreciation and amortization 143.6 143.6 - Stock-based compensation 100.0 100.0 - Deferred income taxes (75.3) (59.3) (16.0) Changes in assets and liabilities: Accounts receivable 22.5 44.1 (21.6) Other current assets 36.6 20.1 16.5 Other assets (7.4) (7.8) 0.4 Accounts payable and accrued liabilities (176.5) (178.4) 1.9 Deferred revenue (35.3) (41.4) 6.1 Unrecognized tax benefits and other non-current tax liabilities 42.8 42.8 - Other liabilities (33.1) (30.1) (3.0) Net cash provided by operating activities $ 1,084.6 $ 1,084.6 $ -
Compensation-Retirement Benefits Accounting Standard [Member] | Income Statement [Member]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	For the Three Months Ended September 30, 2018 For the Three Months Ended September 30, 2017 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) As Adjusted Under previous accounting guidance Effect of Change Higher/(Lower) Operating expenses $ 306.3 $ 307.5 $ (1.2) $ 315.6 $ 317.2 $ (1.6) Selling, general and administrative expenses 260.3 261.4 (1.1) 245.7 247.2 (1.5) Operating income 466.8 464.5 2.3 448.5 445.4 3.1 Interest expense, net (56.4) (51.5) (4.9) (53.1) (48.1) (5.0) Other non-operating income (expense), net 2.4 (0.2) 2.6 0.5 (1.4) 1.9 For the Nine Months Ended September 30, 2018 For the Nine Months Ended September 30, 2017 As Reported Under previous accounting guidance Effect of Change Higher/(Lower) As Adjusted Under previous accounting guidance Effect of Change Higher/(Lower) Operating expenses $ 941.4 $ 944.9 $ (3.5) $ 875.7 $ 880.4 $ (4.7) Selling, general and administrative expenses 801.9 805.1 (3.2) 682.5 686.8 (4.3) Operating income 1,491.6 1,484.9 6.7 1,355.3 1,346.3 9.0 Interest expense, net (160.5) (146.0) (14.5) (150.2) (135.5) (14.7) Other non-operating income (expense), net 18.3 10.5 7.8 3.2 (2.5) 5.7
Cumulative Effect on Start Period [Member] | New Revenue Accounting Standard [Member] | Balance Sheets [Member]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	As Reported December 31, 2017 Adjustment Due to New Revenue Accounting Standard Balance at January 1, 2018 ASSETS Current assets: Cash and cash equivalents $ 1,071.5 $ - $ 1,071.5 Short-term investments 111.8 - 111.8 Accounts receivable, net of allowances 1,147.2 16.8 1,164.0 Other current assets 250.1 32.9 283.0 Total current assets 2,580.6 49.7 2,630.3 Property and equipment, net 325.1 - 325.1 Goodwill 3,753.2 - 3,753.2 Intangible assets, net 1,631.6 - 1,631.6 Deferred tax assets, net 143.8 - 143.8 Other assets 159.9 71.3 231.2 Total assets $ 8,594.2 $ 121.0 $ 8,715.2 LIABILITIES, NONCONTROLLING INTERESTS AND SHAREHOLDERS' (DEFICIT)/EQUITY Current liabilities: Accounts payable and accrued liabilities $ 750.3 $ (0.8) $ 749.5 Commercial paper 129.9 - 129.9 Current portion of long-term debt 299.5 - 299.5 Deferred revenue 883.6 (69.3) 814.3 Total current liabilities 2,063.3 (70.1) 1,993.2 Non-current portion of deferred revenue 140.0 (8.0) 132.0 Long-term debt 5,111.1 - 5,111.1 Deferred tax liabilities, net 341.6 42.7 384.3 Unrecognized tax benefits 389.1 - 389.1 Other liabilities 664.0 0.3 664.3 Total liabilities 8,709.1 (35.1) 8,674.0 Shareholders' (deficit) equity: Common stock 3.4 - 3.4 Capital surplus 528.6 - 528.6 Retained earnings 7,465.4 156.1 7,621.5 Treasury stock (8,152.9) - (8,152.9) Accumulated other comprehensive loss (172.2) - (172.2) Total Moody's shareholders' (deficit) equity (327.7) 156.1 (171.6) Noncontrolling interests 212.8 - 212.8 Total shareholders' (deficit) equity (114.9) 156.1 41.2 Total liabilities, noncontrolling interests and shareholders' (deficit) equity $ 8,594.2 $ 121.0 $ 8,715.2

REVENUES (Tables)

REVENUES (Tables)	9 Months Ended
	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue by Category	Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 (1) 2018 2017 (1) MIS: Corporate finance (CFG) Investment-grade $ 51.0 $ 78.5 $ 199.4 $ 235.2 High-yield 38.3 62.9 154.8 189.8 Bank loans 75.9 82.4 301.9 274.1 Other accounts (2) 130.9 126.4 395.3 359.7 Total CFG 296.1 350.2 1,051.4 1,058.8 Structured finance (SFG) Asset-backed securities 24.6 22.8 80.7 69.6 Residential mortgage backed securities 23.7 21.9 74.8 64.7 Commercial real estate finance 25.9 37.5 90.7 96.7 Structured credit 50.7 45.6 148.6 115.2 Other accounts 0.5 0.5 1.9 1.5 Total SFG 125.4 128.3 396.7 347.7 Financial institutions (FIG) Banking 72.9 70.1 227.2 219.6 Insurance 37.7 23.9 98.9 72.4 Managed investments 5.5 4.6 18.4 15.6 Other accounts 3.4 3.5 9.9 9.2 Total FIG 119.5 102.1 354.4 316.8 Public, project and infrastructure finance (PPIF) Public finance / sovereign 45.3 49.4 143.9 155.6 Project and infrastructure 53.7 59.8 156.4 156.4 Total PPIF 99.0 109.2 300.3 312.0 Total ratings revenue 640.0 689.8 2,102.8 2,035.3 MIS Other 4.8 4.4 14.2 13.8 Total external revenue 644.8 694.2 2,117.0 2,049.1 Intersegment royalty 31.6 29.0 92.0 82.0 Total MIS 676.4 723.2 2,209.0 2,131.1 MA: Research, data and analytics (RD&A) 282.6 218.4 831.7 574.7 Enterprise risk solutions (ERS) 113.0 112.6 318.6 305.8 Professional services (PS) 40.4 37.7 115.3 109.0 Total external revenue 436.0 368.7 1,265.6 989.5 Intersegment revenue 2.6 4.1 10.0 11.6 Total MA 438.6 372.8 1,275.6 1,001.1 Eliminations (34.2) (33.1) (102.0) (93.6) Total MCO $ 1,080.8 $ 1,062.9 $ 3,382.6 $ 3,038.6 (1) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard. (2) Other includes: recurring monitoring fees of a rated debt obligation and/or entities that issue such obligations as well as fees from programs such as commercial paper, medium term notes, and ICRA corporate finance revenue.
Revenue by Line of Business within Each Geographical Segment	Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 (1) United States International Total United States International Total MIS: Corporate finance (CFG) $ 184.0 $ 112.1 $ 296.1 $ 234.0 $ 116.2 $ 350.2 Structured finance (SFG) 81.3 44.1 125.4 89.3 39.0 128.3 Financial institutions (FIG) 59.8 59.7 119.5 40.5 61.6 102.1 Public, project and infrastructure finance (PPIF) 59.4 39.6 99.0 63.8 45.4 109.2 Total ratings revenue 384.5 255.5 640.0 427.6 262.2 689.8 MIS Other 0.2 4.6 4.8 0.1 4.3 4.4 Total MIS 384.7 260.1 644.8 427.7 266.5 694.2 MA: Research, data and analytics (RD&A) 116.7 165.9 282.6 107.5 110.9 218.4 Enterprise risk solutions (ERS) 43.0 70.0 113.0 39.5 73.1 112.6 Professional services (PS) 15.2 25.2 40.4 13.7 24.0 37.7 Total MA 174.9 261.1 436.0 160.7 208.0 368.7 Total MCO $ 559.6 $ 521.2 $ 1,080.8 $ 588.4 $ 474.5 $ 1,062.9 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 (1) United States International Total United States International Total MIS: Corporate finance (CFG) $ 673.0 $ 378.4 $ 1,051.4 $ 698.6 $ 360.2 $ 1,058.8 Structured finance (SFG) 259.2 137.5 396.7 235.9 111.8 347.7 Financial institutions (FIG) 162.7 191.7 354.4 135.0 181.8 316.8 Public, project and infrastructure finance (PPIF) 173.9 126.4 300.3 192.8 119.2 312.0 Total ratings revenue 1,268.8 834.0 2,102.8 1,262.3 773.0 2,035.3 MIS Other 0.5 13.7 14.2 0.3 13.5 13.8 Total MIS 1,269.3 847.7 2,117.0 1,262.6 786.5 2,049.1 MA: Research, data and analytics (RD&A) 347.5 484.2 831.7 310.6 264.1 574.7 Enterprise risk solutions (ERS) 124.1 194.5 318.6 120.1 185.7 305.8 Professional services (PS) 41.8 73.5 115.3 40.7 68.3 109.0 Total MA 513.4 752.2 1,265.6 471.4 518.1 989.5 Total MCO $ 1,782.7 $ 1,599.9 $ 3,382.6 $ 1,734.0 $ 1,304.6 $ 3,038.6 (1) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard.
Transaction and Relationship Revenue	Three Months Ended September 30, 2018 2017 (2) Transaction Relationship Total Transaction Relationship Total Corporate Finance $ 192.0 $ 104.1 $ 296.1 $ 254.3 $ 95.9 $ 350.2 65% 35% 100% 73% 27% 100% Structured Finance $ 81.0 $ 44.4 $ 125.4 $ 84.1 $ 44.2 $ 128.3 65% 35% 100% 66% 34% 100% Financial Institutions $ 56.2 $ 63.3 $ 119.5 $ 40.6 $ 61.5 $ 102.1 47% 53% 100% 40% 60% 100% Public, Project and Infrastructure Finance $ 60.8 $ 38.2 $ 99.0 $ 71.1 $ 38.1 $ 109.2 61% 39% 100% 65% 35% 100% MIS Other $ 0.5 $ 4.3 $ 4.8 $ 0.4 $ 4.0 $ 4.4 10% 90% 100% 9% 91% 100% Total MIS $ 390.5 $ 254.3 $ 644.8 $ 450.5 $ 243.7 $ 694.2 61% 39% 100% 65% 35% 100% Moody's Analytics $ 71.0 (1) $ 365.0 $ 436.0 $ 77.6 (1) $ 291.1 $ 368.7 16% 84% 100% 21% 79% 100% Total Moody's Corporation $ 461.5 $ 619.3 $ 1,080.8 $ 528.1 $ 534.8 $ 1,062.9 43% 57% 100% 50% 50% 100% Nine Months Ended September 30, 2018 2017 (2) Transaction Relationship Total Transaction Relationship Total Corporate Finance $ 741.2 $ 310.2 $ 1,051.4 $ 777.4 $ 281.4 $ 1,058.8 70% 30% 100% 73% 27% 100% Structured Finance $ 259.4 $ 137.3 $ 396.7 $ 216.8 $ 130.9 $ 347.7 65% 35% 100% 62% 38% 100% Financial Institutions $ 162.4 $ 192.0 $ 354.4 $ 137.9 $ 178.9 $ 316.8 46% 54% 100% 44% 56% 100% Public, Project and Infrastructure Finance $ 184.9 $ 115.4 $ 300.3 $ 197.5 $ 114.5 $ 312.0 62% 38% 100% 63% 37% 100% MIS Other $ 1.5 $ 12.7 $ 14.2 $ 1.0 $ 12.8 $ 13.8 11% 89% 100% 7% 93% 100% Total MIS $ 1,349.4 $ 767.6 $ 2,117.0 $ 1,330.6 $ 718.5 $ 2,049.1 64% 36% 100% 65% 35% 100% Moody's Analytics $ 198.3 (1) $ 1,067.3 $ 1,265.6 $ 205.0 $ 784.5 $ 989.5 16% 84% 100% 21% 79% 100% Total Moody's Corporation $ 1,547.7 $ 1,834.9 $ 3,382.6 $ 1,535.6 $ 1,503.0 $ 3,038.6 46% 54% 100% 51% 49% 100% (1) Revenue from software implementation services and risk management advisory projects, while classified by management as transactional revenue, is recognized over time under the New Revenue Accounting Standard (please also refer to the table below). (2) Prior period amounts have not been adjusted under the modified retrospective method of adoption for the New Revenue Accounting Standard.
Schedule of Revenue Recognition Timing	Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 MIS MA Total MIS MA Total Revenue recognized at a point in time $ 390.5 $ 19.5 $ 410.0 $ 1,349.4 $ 49.0 $ 1,398.4 Revenue recognized over time 254.3 416.5 670.8 767.6 1,216.6 1,984.2 Total $ 644.8 $ 436.0 $ 1,080.8 $ 2,117.0 $ 1,265.6 $ 3,382.6
Schedule of Changes in the Deferred Revenue Balances	Three Months Ended September 30, 2018 MIS MA Total Balance at June 30, 2018 $ 377.5 $ 609.0 $ 986.5 Changes in deferred revenue Revenue recognized that was included in the deferred revenue balance at the beginning of the period (127.4) (241.8) (369.2) Increases due to amounts billable excluding amounts recognized as revenue during the period 101.6 176.6 278.2 Effect of exchange rate changes 1.1 (1.2) (0.1) Total changes in deferred revenue (24.7) (66.4) (91.1) Balance at September 30, 2018 $ 352.8 $ 542.6 $ 895.4 Nine Months Ended September 30, 2018 MIS MA Total Balance at January 1, 2018 (after New Revenue Accounting Standard transition adjustment) $ 334.7 $ 611.6 $ 946.3 Changes in deferred revenue Revenue recognized that was included in the deferred revenue balance at the beginning of the period (196.2) (417.1) (613.3) Increases due to amounts billable excluding amounts recognized as revenue during the period 217.6 359.9 577.5 Effect of exchange rate changes (3.3) (11.8) (15.1) Total changes in deferred revenue 18.1 (69.0) (50.9) Balance at September 30, 2018 $ 352.8 $ 542.6 $ 895.4 Deferred revenue - current $ 233.9 $ 537.6 $ 771.5 Deferred revenue - noncurrent $ 118.9 $ 5.0 $ 123.9
MIS [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	MIS Total Less than 1 year 1 - 5 years 6 - 10 Years 11 - 15 years 16-20 years Over 20 Years $ 151.3 $ 22.4 $ 68.0 $ 43.2 $ 7.5 $ 4.2 $ 6.0
MA [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	MA Total Less than 1 Year 1 - 2 Years Over 2 Years $ 1,265.2 $ 930.1 $ 236.1 $ 99.0

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2018
Stock-Based Compensation [Abstract]
Stock-Based Compensation Cost and Associated Tax Benefit	Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Stock-based compensation cost $ 30.5 $ 31.8 $ 100.0 $ 88.9 Tax benefit $ 11.5 $ 10.3 $ 26.0 $ 28.8
Weighted Average Assumptions used in Determining Fair Value for Options Granted	Expected dividend yield 1.05% Expected stock volatility 25.6% Risk-free interest rate 2.81% Expected holding period 6.2 years Grant date fair value $45.87
Stock Option Exercises and Restricted Stock Vesting	Nine months ended September 30, Exercise of stock options: 2018 2017 Proceeds from stock option exercises $ 36.2 $ 44.0 Aggregate intrinsic value $ 94.9 $ 75.7 Tax benefit realized upon exercise $ 23.2 $ 26.9 Number of shares exercised 0.8 1.0 Nine months ended September 30, Vesting of restricted stock: 2018 2017 Fair value of shares vested $ 150.0 $ 109.1 Tax benefit realized upon vesting $ 34.7 $ 34.6 Number of shares vested 0.9 1.0 Nine months ended September 30, Vesting of performance-based restricted stock: 2018 2017 Fair value of shares vested $ 23.0 $ 19.5 Tax benefit realized upon vesting $ 5.6 $ 6.9 Number of shares vested 0.1 0.2

INCOME TAXES (Tables)

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2018
Income Taxes [Abstract]
Income Taxes Paid	Nine months ended September 30, 2018 2017 Income taxes paid $ 337.0 $ 194.7

WEIGHTED AVERAGE SHARES OUTST_2

WEIGHTED AVERAGE SHARES OUTSTANDING (Tables)	9 Months Ended
	Sep. 30, 2018
Weighted Average Shares Outstanding [Abstract]
Reconciliation of Basic to Diluted Shares Outstanding	Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Basic 191.8 191.1 191.7 191.1 Dilutive effect of shares issuable under stock-based compensation plans 2.7 3.0 2.7 3.0 Diluted 194.5 194.1 194.4 194.1 Anti-dilutive options to purchase common shares and restricted stock as well as contingently issuable restricted stock which are excluded from the table above 0.3 0.5 0.4 0.6

CASH EQUIVALENT AND INVESTMEN_2

CASH EQUIVALENT AND INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2018
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	As of September 30, 2018 Balance sheet location Cost Gross Unrealized Gains Fair Value Cash and cash equivalents Short-term investments Other assets Money market mutual funds $ 32.3 $ - $ 32.3 $ 32.3 $ - $ - Certificates of deposit and money market deposit accounts (1) $ 324.0 $ - $ 324.0 $ 202.2 $ 110.7 $ 11.1 Open ended mutual funds $ 31.1 $ 3.6 $ 34.7 $ - $ - $ 34.7 As of December 31, 2017 Balance sheet location Cost Gross Unrealized Gains Fair Value Cash and cash equivalents Short-term investments Other assets Money market mutual funds $ 42.2 $ - $ 42.2 $ 42.2 $ - $ - Certificates of deposit and money market deposit accounts (1) $ 351.4 $ - $ 351.4 $ 238.6 $ 111.8 $ 1.0 Fixed maturity and open ended mutual funds (2) $ 16.8 $ 4.3 $ 21.1 $ - $ - $ 21.1 (1) Consists of time deposits and money market deposit accounts. The remaining contractual maturities for the certificates of deposits classified as short-term investments were one to 12 months at both September 30, 2018 and December 31, 2017. The remaining contractual maturities for the certificates of deposits classified in other assets are 13 to 39 months at September 30, 2018 and 15 to 48 months at December 31, 2017. Time deposits with a maturity of less than 90 days at time of purchase are classified as cash and cash equivalents. (2) At December 31, 2017, the remaining contractual maturities for the fixed maturity instruments were six months to seven months.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables) - Bureau van Dijk (BvD) [Member]	9 Months Ended
	Sep. 30, 2018
Summary of Fair Values of Assets Acquired and Liabilities Assumed	(Amounts in millions) Current assets $ 158.4 Property and equipment, net 4.2 Intangible assets: Customer relationships (23 year weighted average life) $ 998.7 Product technology (12 year weighted average life) 258.5 Trade name (18 year weighted average life) 82.3 Database (10 year weighted average life) 12.9 Total intangible assets (21 year weighted average life) 1,352.4 Goodwill 2,614.7 Other assets 5.9 Liabilities Deferred revenue $ (101.1) Accounts payable and accrued liabilities (44.3) Deferred tax liabilities, net (329.8) Other liabilities (118.4) Total liabilities (593.6) Net assets acquired $ 3,542.0
BvD Pro Forma Information	(Amounts in millions) For nine months ended September 30, 2017 Pro forma Revenue $ 3,226.9 Pro forma Net Income attributable to Moody's $ 965.9

DERIVATIVE INSTRUMENTS AND HE_2

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities [Abstract]
Schedule of Interest Rate Swap	Hedged Item Nature of Swap Notional Amount Floating Interest Rate As of September 30, 2018 As of December 31, 2017 2010 Senior Notes due 2020 Pay Floating/Receive Fixed $ 500.0 $ 500.0 3-month LIBOR 2017 Senior Notes due 2021 Pay Floating/Receive Fixed $ 500.0 $ - 3-month LIBOR 2014 Senior Notes due 2019 Pay Floating/Receive Fixed $ 450.0 $ 450.0 3-month LIBOR 2012 Senior Notes due 2022 Pay Floating/Receive Fixed $ 80.0 $ 80.0 3-month LIBOR
Gains and Losses on Derivatives Designated as Hedging Instruments	Amount of income/(loss) recognized in the consolidated statements of operations Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Total amounts of financial statement line item presented in the statements of operations in which the effects of fair value hedges are recorded Interest expense, net $ (56.4) $ (53.1) $ (160.5) $ (150.2) Descriptions Location on Statement of Operations Net interest settlements and accruals on interest rate swaps Interest expense, net $ (0.5) $ 1.6 $ (1.0) $ 5.8 Fair value changes on interest rate swaps Interest expense, net $ (3.3) $ (2.3) $ (14.8) $ (2.2) Fair value changes on hedged debt Interest expense, net $ 3.3 $ 2.3 $ 14.8 $ 2.2
Amount of Gain/(Loss) Recognized in AOCI on Derivative Net Investment Hedging Relationships (Effectiveness Portion)	Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing) Derivative and Non-Derivative Instruments in Net Investment Hedging Relationships Three Months Ended Three Months Ended Three Months Ended September 30, September 30, September 30, 2018 2017 (a) 2018 2017 (a) 2018 (c) 2017 (d) Cross currency swaps $ 1.8 $ - $ - $ - $ 4.1 $ - FX forwards - 0.4 - - - - Long-term debt 2.2 (10.3) - - - - Total net investment hedges $ 4.0 $ (9.9) $ - $ - $ 4.1 $ - Derivatives in Cash Flow Hedging Relationships Cross currency swap $ - $ 3.2 $ 0.1 $ 2.6 (b) $ - $ - Interest rate contracts - - - - - - Total cash flow hedges $ - $ 3.2 $ 0.1 $ 2.6 $ - $ - Total $ 4.0 $ (6.7) $ 0.1 $ 2.6 $ 4.1 $ - Derivative and Non-Derivative Instruments in Net Investment Hedging Relationships Nine months ended Nine months ended Nine months ended September 30, September 30, September 30, 2018 2017 (a) 2018 2017 (a) 2018 (c) 2017 (d) Cross currency swaps $ 5.8 $ - $ $ - $ 6.2 $ - FX forwards - 1.2 - - - - Long-term debt 14.7 (31.4) - - - - Total net investment hedges $ 20.5 $ (30.2) $ - $ - $ 6.2 $ - Derivatives in Cash Flow Hedging Relationships Cross currency swap $ 1.5 $ 6.6 $ 0.3 $ 7.9 (b) $ - $ 0.4 Interest rate contracts - (0.4) - (1.1) - - Total cash flow hedges $ 1.5 $ 6.2 $ 0.3 $ 6.8 $ - $ 0.4 Total $ 22.0 $ (24.0) $ 0.3 $ 6.8 $ 6.2 $ 0.4 (a) For the three and nine months ended September 30, 2017, amount of gain or (loss) represents only the effective portion of the hedging relationship as this period was prior to the Company’s 2018 initial application of ASU 2017-12. (b) For the three and nine months ended September 30, 2017, reflects $4.2 million and $12.8 million, respectively in gains recorded in other non-operating income (expense), net and $1.6 million and $4.9 million relating to the tax effect of the aforementioned item. (c) Effective with the adoption of ASU 2017-12, the Company has elected to assess the effectiveness of its net investment hedges based on changes in spot exchange rates. Accordingly, amounts recognized directly into Net Income during the three and nine months ended September 30, 2018 related to its cross-currency swaps represent net periodic interest settlements and accruals which are recognized in interest expense, net. (d) For the three and nine months ended September 30, 2017, amount of gain or (loss) recognized directly into income represents the ineffective portion of the hedging relationship. No hedging instruments for which ineffectiveness was recognized directly into Net Income in 2017 or in years prior were outstanding at the date of adoption of ASU 2017-12.
Cumulative Amount of Unrecognized Hedge Losses Recorded in Accumulated Other Comprehensive Income	Cumulative Gains/(Losses), net of tax September 30, December 31, 2018 2017 Net investment hedges Cross currency swaps $ 5.8 $ - FX forwards 23.5 23.5 Long-term debt (10.0) (24.7) Total net investment hedges $ 19.3 $ (1.2) Cash flow hedges Interest rate contracts $ (0.4) $ (0.4) Cross currency swap 2.5 1.3 Total cash flow hedges 2.1 0.9 Total net gain (loss) in AOCI $ 21.4 $ (0.3)
Summary of Notional Amounts of Outstanding Foreign Exchange Forwards	September 30, December 31, 2018 2017 Notional amount of currency pair: Sell Buy Sell Buy Contracts to sell USD for GBP $ 556.8 £ 415.9 $ 484.7 £ 362.3 Contracts to sell USD for Japanese Yen $ 25.5 ¥ 2,700.0 $ 24.3 ¥ 2,700.0 Contracts to sell USD for Canadian dollars $ 85.0 C$ 109.0 $ 51.7 C$ 64.0 Contracts to sell USD for Singapore dollars $ - S$ - $ 39.2 S$ 53.0 Contracts to sell USD for Euros $ 200.8 € 169.9 $ 465.2 € 390.0 NOTE: € = Euro, £ = British pound, $ = U.S. dollar, ¥ = Japanese Yen, C$ = Canadian dollar, S$= Singapore dollars
Gains and Losses Recognized in Consolidated Statement of Operations on Derivatives Not Designated as Hedging instruments	Three Months Ended Nine Months Ended September 30, September 30, Derivatives not designated as accounting hedges Location on Statement of Operations 2018 2017 2018 2017 Foreign exchange forwards Other non-operating income, net $ (11.8) $ 9.2 $ (29.1) $ 14.0 FX collar relating to Bureau van Dijk acquisition Purchase Price Hedge Gain - 59.6 - 100.8 Foreign exchange forwards relating to Bureau van Dijk acquisition Purchase Price Hedge Gain - 10.3 - 10.3 $ (11.8) $ 79.1 $ (29.1) $ 125.1
Fair Value of Derivative Instruments	Derivative and Non-Derivative Instruments Balance Sheet Location September 30, 2018 December 31, 2017 Assets: Derivatives designated as accounting hedges: Cross-currency swaps designated as net investment hedges Other current assets $ 7.8 $ - Interest rate swaps Other assets - 0.5 Total derivatives designated as accounting hedges 7.8 0.5 Derivatives not designated as accounting hedges: FX forwards on certain assets and liabilities Other current assets 2.5 12.5 Total assets $ 10.3 $ 13.0 Liabilities: Derivatives designated as accounting hedges: Interest rate swaps Other current liabilities $ 3.8 $ - Interest rate swaps Other non-current liabilities 14.0 3.5 Total derivatives designated as accounting hedges 17.8 3.5 Non-derivative instrument designated as accounting hedge Long-term debt designated as net investment hedge Long-term debt 580.7 600.4 Derivatives not designated as accounting hedges: FX forwards on certain assets and liabilities Accounts payable and accrued liabilities 20.5 2.0 Total liabilities $ 619.0 $ 605.9

GOODWILL AND OTHER ACQUIRED I_2

GOODWILL AND OTHER ACQUIRED INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Other Acquired Intangible Assets [Abstract]
Activity in Goodwill	Nine months ended September 30, 2018 MIS MA Consolidated Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Balance at beginning of year $ 285.2 $ - $ 285.2 $ 3,480.2 $ (12.2) $ 3,468.0 $ 3,765.4 $ (12.2) $ 3,753.2 Additions/adjustments - - - 23.8 - 23.8 23.8 - 23.8 Foreign currency translation adjustments (13.1) - (13.1) (102.6) - (102.6) (115.7) - (115.7) Ending balance $ 272.1 $ - $ 272.1 $ 3,401.4 $ (12.2) $ 3,389.2 $ 3,673.5 $ (12.2) $ 3,661.3 Year ended December 31, 2017 MIS MA Consolidated Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Gross goodwill Accumulated impairment charge Net goodwill Balance at beginning of year $ 277.0 $ - $ 277.0 $ 758.8 $ (12.2) $ 746.6 $ 1,035.8 $ (12.2) $ 1,023.6 Additions/adjustments - - - 2,622.6 - 2,622.6 2,622.6 - 2,622.6 Foreign currency translation adjustments 8.2 - 8.2 98.8 - 98.8 107.0 - 107.0 Ending balance $ 285.2 $ - $ 285.2 $ 3,480.2 $ (12.2) $ 3,468.0 $ 3,765.4 $ (12.2) $ 3,753.2
Acquired Intangible Assets and Related Amortization	September 30, December 31, 2018 2017 Customer relationships $ 1,312.3 $ 1,345.1 Accumulated amortization (200.9) (159.9) Net customer relationships 1,111.4 1,185.2 Trade secrets 30.1 30.2 Accumulated amortization (28.3) (28.1) Net trade secrets 1.8 2.1 Software/product technology 348.8 358.6 Accumulated amortization (96.2) (78.0) Net software/product technology 252.6 280.6 Trade names 156.4 161.6 Accumulated amortization (33.0) (26.7) Net trade names 123.4 134.9 Other (1) 58.9 57.4 Accumulated amortization (30.5) (28.6) Net other 28.4 28.8 Total acquired intangible assets, net $ 1,517.6 $ 1,631.6 (1) Other intangible assets primarily consist of databases, covenants not to compete, and acquired ratings methodologies and models.
Amortization Expense Relating to Acquired Intangible Assets	Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Amortization expense $ 24.6 $ 18.8 $ 75.4 $ 35.9
Estimated Future Amortization Expense for Acquired Intangible Assets Subject to Amortization	Year Ending December 31, 2018 (after September 30) $ 25.1 2019 95.5 2020 93.1 2021 92.9 2022 92.2 Thereafter 1,118.8 Total estimated future amortization $ 1,517.6

FAIR VALUE (Tables)

FAIR VALUE (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value [Abstract]
Financial Instruments Carried at Fair Value on Recurring Basis	Fair Value Measurement as of September 30, 2018 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 10.3 $ - $ 10.3 Money market mutual funds 32.3 32.3 - Open ended mutual funds 34.7 34.7 - Total $ 77.3 $ 67.0 $ 10.3 Liabilities: Derivatives (a) $ 38.3 $ - $ 38.3 Total $ 38.3 $ - $ 38.3 Fair Value Measurement as of December 31, 2017 Description Balance Level 1 Level 2 Assets: Derivatives (a) $ 13.0 $ - $ 13.0 Money market mutual funds 42.2 42.2 - Fixed maturity and open ended mutual funds 21.1 21.1 - Total $ 76.3 $ 63.3 $ 13.0 Liabilities: Derivatives (a) $ 5.5 $ - $ 5.5 Total $ 5.5 $ - $ 5.5 (a) Represents FX forwards on certain assets and liabilities as well as interest rate swaps and cross-currency swaps as more fully described in Note 9 to the condensed consolidated financial statements.

OTHER BALANCE SHEET AND STATE_2

OTHER BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2018
Other Balance Sheet And Statement Of Operations Information [Abstract]
Additional Details Related to Certain Balance Sheet Captions	September 30, December 31, 2018 2017 Other current assets: Prepaid taxes $ 77.1 $ 94.9 Prepaid expenses 78.9 91.7 Capitalized costs to obtain and fulfill sales contracts (1) 39.3 15.9 Other 43.6 47.6 Total other current assets $ 238.9 $ 250.1 September 30, December 31, 2018 2017 Other assets: Investments in joint ventures $ 98.3 $ 99.1 Deposits for real-estate leases 13.0 12.3 Indemnification assets related to acquisitions 15.8 17.0 Mutual funds and fixed deposits 45.8 22.1 Costs to obtain sales contracts (1) 68.0 - Other 2.7 9.4 Total other assets $ 243.6 $ 159.9 (1) The 2018 amount reflects capitalized costs to obtain sales contracts (sales commissions) pursuant to the adoption of the New Revenue Accounting Standard, which are amortized over an average 7 year period as well as costs incurred and capitalized for in process ratings (current assets only). September 30, December 31, 2018 2017 Accounts payable and accrued liabilities: Salaries and benefits $ 91.9 $ 129.6 Incentive compensation 133.7 246.7 Customer credits, advanced payments and advanced billings 23.2 22.2 Self-insurance reserves 13.1 8.1 Dividends 5.6 6.2 Professional service fees 50.7 47.1 Interest accrued on debt 36.2 73.9 Accounts payable 16.2 21.8 Income taxes 79.9 79.2 Pension and other retirement employee benefits (see Note 14) 5.9 5.9 Accrued royalties 13.5 26.4 Foreign exchange forwards on certain assets and liabilities 20.5 2.0 Other 91.2 81.2 Total accounts payable and accrued liabilities $ 581.6 $ 750.3 September 30, December 31, 2018 2017 Other liabilities: Pension and other retirement employee benefits (see Note 14) $ 252.7 $ 244.5 Deferred rent - non-current portion 96.6 103.1 Interest accrued on UTPs 65.0 54.7 Other tax matters 1.3 1.3 Income tax liability - non-current (2) 122.6 232.2 Interest rate swaps 14.0 3.5 Other 22.7 24.7 Total other liabilities $ 574.9 $ 664.0 (2) Primarily reflects the transition tax pursuant to the Tax Act, which was enacted into law in December 2017.
Self Insurance Reserves	Nine months ended Year Ended September 30, December 31, 2018 2017 Balance January 1, $ 8.1 $ 11.1 Accruals (reversals), net 4.9 9.6 Payments 0.1 (12.6) Balance $ 13.1 $ 8.1
Other Non-Operating	Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 FX loss $ (3.9) $ (6.7) $ (3.6) $ (12.5) Net periodic pension costs - other components (1) 2.6 1.9 7.8 5.7 Joint venture income 3.3 2.7 9.2 7.7 Other 0.4 2.6 4.9 2.3 Total $ 2.4 $ 0.5 18.3 $ 3.2 (1) The Company adopted ASU No. 2017-07 in the first quarter of 2018, whereby all components of pension expense except for the service cost component are required to be presented in other non-operating income. The service cost component continues to be reported as an operating expense.
Schedule of Minority Interest	Non-Controlling Interests Balance at December 31, 2016 $ 197.7 Net income 7.1 Dividends (3.3) Purchase of noncontrolling interest (1.0) Non-controlling interests portion of foreign currency translation adjustments 13.0 Net realized and unrealized gain on available for sale securities (0.7) Balance at December 31, 2017 $ 212.8 Net income 7.4 Dividends (4.0) Non-controlling interests portion of foreign currency translation adjustments (10.2) Balance at September 30, 2018 $ 206.0

COMPREHENSIVE INCOME AND ACCU_2

COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	9 Months Ended
	Sep. 30, 2018
Comprehensive Income And Accumulated Other Comprehensive Income [Abstract]
Reclassifications out of AOCI	Three Months Ended September 30, 2018 Nine months ended September 30, 2018 Affected line in the consolidated statement of operations Gains on cash flow hedges Cross-currency swap $ 0.1 $ 0.3 Interest expense, net Income tax effect of items above - - Provision for income taxes Total net gains on cash flow hedges 0.1 0.3 Pension and other retirement benefits Amortization of actuarial losses and prior service costs included in net income (0.6) (2.2) Operating expense Amortization of actuarial losses and prior service costs included in net income (0.5) (1.3) SG&A expense Total before income taxes (1.1) (3.5) Income tax effect of item above 0.3 1.0 Provision for income taxes Total pension and other retirement benefits (0.8) (2.5) Total losses included in Net Income attributable to reclassifications out of AOCI $ (0.7) $ (2.2) Three Months Ended September 30, 2017 Nine months ended September 30, 2017 Affected line in the consolidated statement of operations Gains on cash flow hedges Cross-currency swap $ 3.5 $ 12.1 Other non-operating expense, net Treasury rate lock 0.7 (0.4) Interest expense, net Total before income taxes 4.2 11.7 Income tax effect of item above (1.6) (4.9) Provision for income taxes Total net gains on cash flow hedges 2.6 6.8 Gains on available for sale securities: Gains on available for sale securities 1.1 1.1 Other non-operating income (expense), net Total gains on available for sale securities 1.1 1.1 Pension and other retirement benefits Amortization of actuarial losses and prior service costs included in net income (1.3) (4.0) Operating expense Amortization of actuarial losses and prior service costs included in net income (0.8) (2.4) SG&A expense Total before income taxes (2.1) (6.4) Income tax effect of item above 0.8 2.5 Provision for income taxes Total pension and other retirement benefits (1.3) (3.9) Total net gains included in Net Income attributable to reclassifications out of AOCI $ 2.4 $ 4.0
Components of Accumulated Other Comprehensive Income	Three Months Ended September 30, 2018 September 30, 2017 Gains/(Losses) Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Balance June 30, $ (58.6) $ 2.2 $ (248.4) $ - $ (304.8) $ (72.0) $ 0.5 $ (241.8) $ 3.6 $ (309.7) Other comprehensive income/(loss) before reclassifications - - (37.9) - (37.9) - 3.2 50.8 0.3 54.3 Amounts reclassified from AOCI 0.8 (0.1) - - 0.7 1.3 (2.6) - (1.1) (2.4) Other comprehensive income/(loss) 0.8 (0.1) (37.9) - (37.2) 1.3 0.6 50.8 (0.8) 51.9 Balance September 30, $ (57.8) $ 2.1 $ (286.3) $ - $ (342.0) $ (70.7) $ 1.1 $ (191.0) $ 2.8 $ (257.8) Nine months ended September 30, 2018 September 30, 2017 Gains/(Losses) Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Pension and Other Retirement Benefits Gains/ (Losses) on Cash Flow Hedges Foreign Currency Translation Adjustments Gains on Available for Sale Securities Total Balance December 31, $ (61.5) $ 0.9 $ (113.9) $ 2.3 $ (172.2) $ (79.5) $ 1.7 $ (290.2) $ 3.1 $ (364.9) Adoption of ASU 2016-01 (Refer to Note 1 and Note 2) - - - (2.3) (2.3) - - - - - Other comprehensive income/(loss) before reclassifications 1.2 1.5 (172.4) - (169.7) 4.9 6.2 99.2 0.8 111.1 Amounts reclassified from AOCI 2.5 (0.3) - - 2.2 3.9 (6.8) - (1.1) (4.0) Other comprehensive income/(loss) 3.7 1.2 (172.4) (2.3) (169.8) 8.8 (0.6) 99.2 (0.3) 107.1 Balance September 30, $ (57.8) $ 2.1 $ (286.3) $ - $ (342.0) $ (70.7) $ 1.1 $ (191.0) $ 2.8 $ (257.8)

PENSION AND OTHER POST-RETIRE_2

PENSION AND OTHER POST-RETIREMENT BENEFITS (Tables)	9 Months Ended
	Sep. 30, 2018
Pension And Other Retirement Benefits [Abstract]
Components of Net Periodic Benefit Expense Related to Post-Retirement Plans	Three Months Ended September 30, Pension Plans Other Retirement Plans 2018 2017 2018 2017 Components of net periodic expense Service cost $ 4.6 $ 4.6 $ 0.7 $ 0.7 Interest cost 4.4 4.7 0.3 0.2 Expected return on plan assets (3.8) (4.1) - - Amortization of net actuarial loss from earlier periods 1.5 2.1 - 0.1 Amortization of net prior service costs from earlier periods - - (0.1) (0.1) Net periodic expense $ 6.7 $ 7.3 $ 0.9 $ 0.9 Nine months ended September 30, Pension Plans Other Retirement Plans 2018 2017 2018 2017 Components of net periodic expense Service cost $ 14.0 $ 13.8 $ 2.2 $ 1.9 Interest cost 13.2 13.9 0.8 0.8 Expected return on plan assets (11.4) (12.4) - - Amortization of net actuarial loss from earlier periods 4.6 6.6 - 0.1 Amortization of net prior service costs from earlier periods (0.2) - (0.2) (0.2) Net periodic expense $ 20.2 $ 21.9 $ 2.8 $ 2.6

INDEBTEDNESS (Tables)

INDEBTEDNESS (Tables)	9 Months Ended
	Sep. 30, 2018
Indebtedness [Abstract]
Summary of Total Indebtedness	September 30, 2018 Principal Amount Fair Value of Interest Rate Swaps (1) Unamortized (Discount) Premium Unamortized Debt Issuance Costs Carrying Value Notes Payable: 5.50% 2010 Senior Notes, due 2020 $ 500.0 $ (8.3) $ (0.7) $ (0.8) $ 490.2 4.50% 2012 Senior Notes, due 2022 500.0 (3.1) (1.7) (1.5) 493.7 4.875% 2013 Senior Notes, due 2024 500.0 - (1.6) (2.1) 496.3 2.75% 2014 Senior Notes (5-Year), due 2019 450.0 (3.8) (0.1) (0.5) 445.6 5.25% 2014 Senior Notes (30-Year), due 2044 600.0 - 3.3 (5.5) 597.8 1.75% 2015 Senior Notes, due 2027 580.7 - - (3.2) 577.5 2.75% 2017 Senior Notes, due 2021 500.0 (2.6) (1.1) (2.6) 493.7 2.625% 2017 Senior Notes, due 2023 500.0 - (0.9) (3.1) 496.0 3.25% 2017 Senior Notes, due 2028 500.0 - (4.9) (3.8) 491.3 3.25% 2018 Senior Notes, due 2021 300.0 - (0.4) (1.6) 298.0 2017 Term Loan Facility, due 2020 50.0 - - (0.5) 49.5 Commercial Paper 25.0 - (0.1) - 24.9 Total debt $ 5,005.7 $ (17.8) $ (8.2) $ (25.2) $ 4,954.5 Current portion (470.5) Total long-term debt $ 4,484.0 December 31, 2017 Principal Amount Fair Value of Interest Rate Swaps (1) Unamortized (Discount) Premium Unamortized Debt Issuance Costs Carrying Value Notes Payable: 5.50% 2010 Senior Notes, due 2020 $ 500.0 $ - $ (1.0) $ (1.2) $ 497.8 4.50% 2012 Senior Notes, due 2022 500.0 (0.8) (2.0) (1.7) 495.5 4.875% 2013 Senior Notes, due 2024 500.0 - (1.8) (2.4) 495.8 2.75% 2014 Senior Notes (5-Year), due 2019 450.0 (2.2) (0.2) (1.1) 446.5 5.25% 2014 Senior Notes (30-Year), due 2044 600.0 - 3.3 (5.7) 597.6 1.75% 2015 Senior Notes, due 2027 600.4 - - (3.6) 596.8 2.75% 2017 Senior Notes, due 2021 500.0 - (1.3) (3.2) 495.5 2017 Floating Rate Senior Notes, due 2018 300.0 - - (0.5) 299.5 2.625% 2017 Senior Notes, due 2023 500.0 - (1.1) (3.5) 495.4 3.25% 2017 Senior Notes, due 2028 500.0 - (5.2) (3.9) 490.9 2017 Term Loan Facility, due 2020 500.0 - - (0.7) 499.3 Commercial Paper 130.0 - (0.1) - 129.9 Total debt $ 5,580.4 $ (3.0) $ (9.4) $ (27.5) $ 5,540.5 Current portion (429.4) Total long-term debt $ 5,111.1 (1) The Company has entered into interest rate swaps on the 2010 Senior Notes, the 2012 Senior Notes, the 2014 Senior Notes (5-Year) and the 2017 Senior Notes due 2021 which are more fully discussed in Note 9 above. These amounts represent the cumulative amount of fair value hedging adjustments included in the carrying amount of the hedged debt.
Principal Payments Due on Long-Term Borrowings	Year Ending December 31, 2010 Senior Notes due 2020 2012 Senior Notes due 2022 2013 Senior Notes due 2024 2014 Senior Notes (5-year) due 2019 2014 Senior Notes (30-year) due 2044 2015 Senior Notes due 2027 2017 Term Loan Facility due 2020 2017 Senior Notes due 2021 2017 Notes due 2023 2017 Notes due 2028 2018 Notes due 2021 Commercial Paper Total 2018 (after September 30,) $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ 25.0 $ 25.0 2019 - - - 450.0 - - - - - - - - 450.0 2020 500.0 - - - - - 50.0 - - - - - 550.0 2021 - - - - - - - 500.0 - - 300.0 - 800.0 2022 - 500.0 - - - - - - - - - - 500.0 Thereafter - - 500.0 - 600.0 580.7 - - 500.0 500.0 - - 2,680.7 Total $ 500.0 $ 500.0 $ 500.0 $ 450.0 $ 600.0 $ 580.7 $ 50.0 $ 500.0 $ 500.0 $ 500.0 $ 300.0 $ 25.0 $ 5,005.7
Summary of Components of Interest as Presented in Consolidated Statements of Operations	Three Months Ended Nine months ended September 30, September 30, 2018 2017 2018 2017 Income $ 4.1 $ 4.3 $ 10.7 $ 13.0 Expense on borrowings (46.4) (48.8) (147.1) (139.9) UTPs and other tax related liabilities (9.6) (3.9) (10.6) (9.4) Net periodic pension costs - interest component (1) (4.9) (5.0) (14.5) (14.7) Capitalized 0.4 0.3 1.0 0.8 Total $ (56.4) $ (53.1) $ (160.5) $ (150.2) (1) The Company adopted ASU No. 2017-07 in the first quarter of 2018, whereby all components of pension expense except for the service cost component are required to be presented in other non-operating income. The service cost component continues to be reported as an operating expense.
Interest Paid	Nine months ended September 30, 2018 2017 Interest paid $ 169.7 $ 136.2
Fair Value and Carrying Value of Long-Term Debt	September 30, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value 5.50% 2010 Senior Notes, due 2020 $ 490.2 $ 519.7 $ 497.8 $ 537.9 4.50% 2012 Senior Notes, due 2022 493.7 514.8 495.5 535.6 4.875% 2013 Senior Notes, due 2024 496.3 522.2 495.8 547.8 2.75% 2014 Senior Notes (5-Year), due 2019 445.6 449.4 446.5 452.8 5.25% 2014 Senior Notes (30-Year), due 2044 597.8 667.1 597.6 722.4 1.75% 2015 Senior Notes, due 2027 577.5 594.8 596.8 617.7 2.75% 2017 Senior Notes, due 2021 493.7 488.6 495.5 500.0 2017 Floating Rate Senior Notes, due 2018 - - 299.5 300.2 2.625% 2017 Senior Notes, due 2023 496.0 478.5 495.4 494.8 3.25% 2017 Senior Notes, due 2028 491.3 469.1 490.9 493.6 2017 Term Loan Facility, due 2020 49.5 49.5 499.3 499.3 3.25% 2018 Senior Notes, due 2021 298.0 298.7 - - Total $ 4,929.6 $ 5,052.4 $ 5,410.6 $ 5,702.1

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Information [Abstract]
Financial Information by Segment	Three Months Ended September 30, 2018 2017 MIS MA Eliminations Consolidated MIS* MA* Eliminations Consolidated* Revenue $ 676.4 $ 438.6 $ (34.2) $ 1,080.8 $ 723.2 $ 372.8 $ (33.1) $ 1,062.9 Operating, SG&A 287.7 313.1 (34.2) 566.6 317.3 277.1 (33.1) 561.3 Adjusted Operating Income 388.7 125.5 - 514.2 405.9 95.7 - 501.6 Less: Depreciation and amortization 15.8 30.3 - 46.1 18.6 24.4 - 43.0 Acquisition-Related Expenses - 1.3 - 1.3 - 10.1 - 10.1 Operating income $ 372.9 $ 93.9 $ - $ 466.8 $ 387.3 $ 61.2 $ - $ 448.5 Nine Months Ended September 30, 2018 2017 MIS MA Eliminations Consolidated MIS* MA* Eliminations Consolidated* Revenue $ 2,209.0 $ 1,275.6 $ (102.0) $ 3,382.6 $ 2,131.1 $ 1,001.1 $ (93.6) $ 3,038.6 Operating, SG&A 901.7 943.6 (102.0) 1,743.3 893.2 758.6 (93.6) 1,558.2 Adjusted Operating Income 1,307.3 332.0 - 1,639.3 1,237.9 242.5 - 1,480.4 Less: Depreciation and amortization 49.3 94.3 - 143.6 56.4 52.0 - 108.4 Acquisition-Related Expenses - 4.1 - 4.1 - 16.7 - 16.7 Operating income $ 1,258.0 $ 233.6 $ - $ 1,491.6 $ 1,181.5 $ 173.8 $ - $ 1,355.3 *Pursuant to the adoption of a new accounting standard relating to pension accounting as more fully discussed in Note 1, only the service cost component of net periodic pension expense will be classified within operating and SG&A expenses with the remaining components being classified as non-operating expenses. Prior period segment results have been restated to reflect this reclassification. Accordingly, operating and SG&A expenses for MIS and MA for the three months ended September 30, 2017 were reduced by $1.9 million and $1.2 million. For the nine months ended September 30, 2017, operating and SG&A expenses for MIS and MA were reduced by $5.7 million and $3.3 million, respectively.
Consolidated Revenue Information by Geographic Area	Consolidated Revenue Information by Geographic Area: Three Months Ended September 30, Nine months ended September 30, 2018 2017 2018 2017 United States $ 559.6 $ 588.4 $ 1,782.7 $ 1,734.0 International: EMEA 344.5 291.0 1,047.9 779.3 Asia-Pacific 123.0 118.6 366.9 336.0 Americas 53.7 64.9 185.1 189.3 Total International 521.2 474.5 1,599.9 1,304.6 Total $ 1,080.8 $ 1,062.9 $ 3,382.6 $ 3,038.6

Description of Business and B_3

Description of Business and Basis of Presentation - Adjustment to Retained Earnings (Detail) - Retained Earnings [Member] $ in Millions	Sep. 30, 2018USD ($)
New Revenue Accounting Standard [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	$ 156
Capitalization of Work-In-Process for In-Progress Ratings [Member] | Other Current Assets [Member] | New Revenue Accounting Standard [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	9
Other Adjustments [Member] | Various Assets [Member] | New Revenue Accounting Standard [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	4
Increase in Tax Liability [Member] | Deferred Tax Liabilities [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	(43)
MA [Member] | Recognition of Deferred Revenue / Increase in Unbilled Receivables [Member] | Deferred Revenue Accounts Receivable and Other Assets [Member] | New Revenue Accounting Standard [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	108
MA [Member] | Increase to Capitalized Sales Commissions [Member] | Other current assets, Other assets, Accounts Payable and Accrued Liabilities [Member] | New Revenue Accounting Standard [Member]
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Effect of adoption adjustment Reduction to retained earnings	$ 78

Description of Business and B_4

Description of Business and Basis of Presentation - Cumulative Effect of the Change in Beginning Financial Position for the adoption of Revenue Accounting Standard (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,034.8			$ 1,071.5	$ 962.8		$ 2,051.5
Short-term investments	110.7			111.8
Accounts receivable, net of allowances	1,131.8			1,147.2
Other current assets	238.9			250.1
Assets Current	2,516.2			2,580.6
Property and equipment, net	311.1			325.1
Goodwill	3,661.3			3,753.2			1,023.6
Intangible assets, net	1,517.6			1,631.6
Deferred tax assets, net	189.3			143.8
Other assets	243.6			159.9
Total Assets	8,439.1			8,594.2
Current liabilities:
Accounts payable and accrued liabilities	581.6			750.3
Commercial paper	24.9			129.9
Current portion of long-term debt	445.6			299.5
Deferred revenue	771.5			883.6
Total current liabilities	1,823.6			2,063.3
Non-current portion of deferred revenue	123.9			140
Long-term debt	4,484			5,111.1
Deferred tax liabilities, net	354.8			341.6
Unrecognized tax benefits	471.8			389.1
Other liabilities	574.9			664
Total liabilities	7,833			8,709.1
Shareholders' (deficit) equity
Common stock	3.4			3.4
Capital surplus	569.7			528.6
Retained earnings	8,429.1			7,465.4
Treasury stock, value	(8,260.1)			(8,152.9)
Accumulated other comprehensive loss	(342)	$ (304.8)		(172.2)	$ (257.8)	$ (309.7)	(364.9)
Total Moody's shareholders' deficit	400.1			(327.7)
Noncontrolling interests	206			212.8			$ 197.7
Total shareholders' deficit	606.1			(114.9)
Total liabilities and shareholders' (deficit) equity	8,439.1			$ 8,594.2
New Revenue Accounting Standard [Member]
Current assets:
Cash and cash equivalents			$ 1,071.5
Short-term investments			111.8
Accounts receivable, net of allowances			1,164
Other current assets			283
Assets Current			2,630.3
Property and equipment, net			325.1
Goodwill			3,753.2
Intangible assets, net			1,631.6
Deferred tax assets, net			143.8
Other assets			231.2
Total Assets			8,715.2
Current liabilities:
Accounts payable and accrued liabilities			749.5
Commercial paper			129.9
Current portion of long-term debt			299.5
Deferred revenue			814.3
Total current liabilities			1,993.2
Non-current portion of deferred revenue			132
Long-term debt			5,111.1
Deferred tax liabilities, net			384.3
Unrecognized tax benefits			389.1
Other liabilities			664.3
Total liabilities			8,674
Shareholders' (deficit) equity
Common stock			3.4
Capital surplus			528.6
Retained earnings			7,621.5
Treasury stock, value			(8,152.9)
Accumulated other comprehensive loss			(172.2)
Total Moody's shareholders' deficit			(171.6)
Noncontrolling interests			212.8
Total shareholders' deficit			41.2
Total liabilities and shareholders' (deficit) equity			8,715.2
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | New Revenue Accounting Standard [Member]
Current assets:
Accounts receivable, net of allowances	38.4		16.8
Other current assets	16.4		32.9
Assets Current	54.8		49.7
Other assets	71		71.3
Total Assets	125.8		121
Current liabilities:
Accounts payable and accrued liabilities	0.2		(0.8)
Deferred revenue	(65)		(69.3)
Total current liabilities	(64.8)		(70.1)
Non-current portion of deferred revenue	(6.2)		(8)
Deferred tax liabilities, net	24		42.7
Other liabilities	0.1		0.3
Total liabilities	(46.9)		(35.1)
Shareholders' (deficit) equity
Retained earnings	172.7		156.1
Total Moody's shareholders' deficit	172.7		156.1
Total shareholders' deficit	172.7		156.1
Total liabilities and shareholders' (deficit) equity	$ 125.8		$ 121

Description of Business and B_5

Description of Business and Basis of Presentation - Effect of Change in Income Statement due to adoption of Revenue Accounting Standard (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
Expenses
Operating	306.3	315.6	941.4	875.7
Selling, general and administrative	260.3	245.7	801.9	682.5
Depreciation and amortization	46.1	43	143.6	108.4
Acquisition-Related Expenses	1.3	10.1	4.1	16.7
Total expenses	614	614.4	1,891	1,683.3
Operating income	466.8	448.5	1,491.6	1,355.3
Non-operating (expense) income, net
Interest income (expense), net	(56.4)	(53.1)	(160.5)	(150.2)
Other non-operating income (expense), net	2.4	0.5	18.3	3.2
Total non-operating (expense) income, net	(54)	17.3	(142.2)	23.8
Income before provisions for income taxes	412.8	465.8	1,349.4	1,379.1
Provision for income taxes	100.8	146.1	282.7	399.9
Net income	312	319.7	1,066.7	979.2
Less: Net income attributable to noncontrolling interests	1.8	2.4	7.4	4.1	$ 7.1
Net income attributable to Moody's	$ 310.2	$ 317.3	$ 1,059.3	$ 975.1
Earnings per share attributable to Moody's common shareholders
Basic	$ 1.62	$ 1.66	$ 5.53	$ 5.1
Diluted	$ 1.59	$ 1.63	$ 5.45	$ 5.02
Weighted average number of shares outstanding
Basic	191.8	191.1	191.7	191.1
Diluted	194.5	194.1	194.4	194.1
Under Previous Accounting Guidance [Member] | New Revenue Accounting Standard [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 1,072.4		$ 3,368.7
Expenses
Operating	306.6		942.8
Selling, general and administrative	263.4		807.4
Depreciation and amortization	46.1		143.6
Acquisition-Related Expenses	1.3		4.1
Total expenses	617.4		1,897.9
Operating income	455		1,470.8
Non-operating (expense) income, net
Interest income (expense), net	(56.4)		(160.5)
Other non-operating income (expense), net	2.4		18.3
Total non-operating (expense) income, net	(54)		(142.2)
Income before provisions for income taxes	401		1,328.6
Provision for income taxes	98.4		277.6
Net income	302.6		1,051
Less: Net income attributable to noncontrolling interests	1.8		7.4
Net income attributable to Moody's	$ 300.8		$ 1,043.6
Earnings per share attributable to Moody's common shareholders
Basic	$ 1.57		$ 5.44
Diluted	$ 1.55		$ 5.37
Weighted average number of shares outstanding
Basic	191.8		191.7
Diluted	194.5		194.4
Effect of Change [Member] | New Revenue Accounting Standard [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 8.4		$ 13.9
Expenses
Operating	(0.3)		(1.4)
Selling, general and administrative	(3.1)		(5.5)
Total expenses	(3.4)		(6.9)
Operating income	11.8		20.8
Non-operating (expense) income, net
Income before provisions for income taxes	11.8		20.8
Provision for income taxes	2.4		5.1
Net income	9.4		15.7
Net income attributable to Moody's	$ 9.4		$ 15.7
Earnings per share attributable to Moody's common shareholders
Basic	$ 0.05		$ 0.09
Diluted	$ 0.04		$ 0.08

Description of Business and B_6

Description of Business and Basis of Presentation - Effect of Change in Balance Sheets from applying the Provision of the Revenue Accounting Standard (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,034.8			$ 1,071.5	$ 962.8		$ 2,051.5
Short-term investments	110.7			111.8
Accounts receivable, net of allowances	1,131.8			1,147.2
Other current assets	238.9			250.1
Total current assets	2,516.2			2,580.6
Property and equipment, net	311.1			325.1
Goodwill	3,661.3			3,753.2			1,023.6
Intangible assets, net	1,517.6			1,631.6
Deferred tax assets, net	189.3			143.8
Other assets	243.6			159.9
Total Assets	8,439.1			8,594.2
Current liabilities:
Accounts payable and accrued liabilities	581.6			750.3
Commercial Paper	24.9			129.9
Current portion of long-term debt	445.6			299.5
Deferred revenue	771.5			883.6
Liabilities Current	1,823.6			2,063.3
Non-current portion of deferred revenue	123.9			140
Long-term debt	4,484			5,111.1
Deferred tax liabilities, net	354.8			341.6
Unrecognized tax benefits	471.8			389.1
Other liabilities	574.9			664
Total liabilities	7,833			8,709.1
Shareholders' (deficit) equity
Common stock	3.4			3.4
Capital surplus	569.7			528.6
Retained earnings	8,429.1			7,465.4
Treasury stock, value	(8,260.1)			(8,152.9)
Accumulated other comprehensive loss	(342)	$ (304.8)		(172.2)	$ (257.8)	$ (309.7)	(364.9)
Total Moody's shareholders' deficit	400.1			(327.7)
Noncontrolling interests	206			212.8			$ 197.7
Total shareholders' deficit	606.1			(114.9)
Total liabilities and shareholders' (deficit) equity	8,439.1			$ 8,594.2
New Revenue Accounting Standard [Member]
Current assets:
Cash and cash equivalents			$ 1,071.5
Short-term investments			111.8
Accounts receivable, net of allowances			1,164
Other current assets			283
Total current assets			2,630.3
Property and equipment, net			325.1
Goodwill			3,753.2
Intangible assets, net			1,631.6
Deferred tax assets, net			143.8
Other assets			231.2
Total Assets			8,715.2
Current liabilities:
Accounts payable and accrued liabilities			749.5
Commercial Paper			129.9
Current portion of long-term debt			299.5
Deferred revenue			814.3
Liabilities Current			1,993.2
Non-current portion of deferred revenue			132
Long-term debt			5,111.1
Deferred tax liabilities, net			384.3
Unrecognized tax benefits			389.1
Other liabilities			664.3
Total liabilities			8,674
Shareholders' (deficit) equity
Common stock			3.4
Capital surplus			528.6
Retained earnings			7,621.5
Treasury stock, value			(8,152.9)
Accumulated other comprehensive loss			(172.2)
Total Moody's shareholders' deficit			(171.6)
Noncontrolling interests			212.8
Total shareholders' deficit			41.2
Total liabilities and shareholders' (deficit) equity			8,715.2
Under Previous Accounting Guidance [Member] | New Revenue Accounting Standard [Member]
Current assets:
Cash and cash equivalents	1,034.8
Short-term investments	110.7
Accounts receivable, net of allowances	1,093.4
Other current assets	222.5
Total current assets	2,461.4
Property and equipment, net	311.1
Goodwill	3,661.3
Intangible assets, net	1,517.6
Deferred tax assets, net	189.3
Other assets	172.6
Total Assets	8,313.3
Current liabilities:
Accounts payable and accrued liabilities	581.4
Commercial Paper	24.9
Current portion of long-term debt	445.6
Deferred revenue	836.5
Liabilities Current	1,888.4
Non-current portion of deferred revenue	130.1
Long-term debt	4,484
Deferred tax liabilities, net	330.8
Unrecognized tax benefits	471.8
Other liabilities	574.8
Total liabilities	7,879.9
Shareholders' (deficit) equity
Common stock	3.4
Capital surplus	569.7
Retained earnings	8,256.4
Treasury stock, value	(8,260.1)
Accumulated other comprehensive loss	(342)
Total Moody's shareholders' deficit	227.4
Noncontrolling interests	206
Total shareholders' deficit	433.4
Total liabilities and shareholders' (deficit) equity	8,313.3
Effect of Change [Member] | New Revenue Accounting Standard [Member]
Current assets:
Accounts receivable, net of allowances	38.4		16.8
Other current assets	16.4		32.9
Total current assets	54.8		49.7
Other assets	71		71.3
Total Assets	125.8		121
Current liabilities:
Accounts payable and accrued liabilities	0.2		(0.8)
Deferred revenue	(65)		(69.3)
Liabilities Current	(64.8)		(70.1)
Non-current portion of deferred revenue	(6.2)		(8)
Deferred tax liabilities, net	24		42.7
Other liabilities	0.1		0.3
Total liabilities	(46.9)		(35.1)
Shareholders' (deficit) equity
Retained earnings	172.7		156.1
Total Moody's shareholders' deficit	172.7		156.1
Total shareholders' deficit	172.7		156.1
Total liabilities and shareholders' (deficit) equity	$ 125.8		$ 121

Description of Business and B_7

Description of Business and Basis of Presentation - Effect of Change within Cash Flow from applying the Provision of the Revenue Accounting Standard (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 312	$ 319.7	$ 1,066.7	$ 979.2
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization	46.1	43	143.6	108.4
Stock-based compensation expense	30.5	$ 31.8	100	88.9
Deferred income taxes			(75.3)	161.4
Changes in assets and liabilities:
Accounts receivable			22.5	(9.8)
Other current assets			36.6	(16.2)
Other assets			(7.4)	11.4
Accounts payable and accrued liabilities			(176.5)	(827.2)
Deferred revenue			(35.3)	(19.3)
Unrecognized tax benefits and other non-current tax liabilities			42.8	18.4
Other liabilities			(33.1)	25.4
Net cash provided by (used in) operating activities			1,084.6	$ 349.8
Under Previous Accounting Guidance [Member] | New Revenue Accounting Standard [Member]
Cash flows from operating activities
Net income	302.6		1,051
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization	46.1		143.6
Stock-based compensation expense			100
Deferred income taxes			(59.3)
Changes in assets and liabilities:
Accounts receivable			44.1
Other current assets			20.1
Other assets			(7.8)
Accounts payable and accrued liabilities			(178.4)
Deferred revenue			(41.4)
Unrecognized tax benefits and other non-current tax liabilities			42.8
Other liabilities			(30.1)
Net cash provided by (used in) operating activities			1,084.6
Effect of Change [Member]
Changes in assets and liabilities:
Deferred revenue	(91.1)		(50.9)
Effect of Change [Member] | New Revenue Accounting Standard [Member]
Cash flows from operating activities
Net income	$ 9.4		15.7
Reconciliation of net income to net cash provided by operating activities:
Deferred income taxes			(16)
Changes in assets and liabilities:
Accounts receivable			(21.6)
Other current assets			16.5
Other assets			0.4
Accounts payable and accrued liabilities			1.9
Deferred revenue			6.1
Other liabilities			$ (3)

Description of Business and B_8

Description of Business and Basis of Presentation - Effect of Change within Income Statement related to the Adoption of New Compensation - Retirement Benefit Policy (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income (Loss) from Continuing Operations before Income Taxes [Abstract]
Operating expenses	$ 306.3	$ 315.6	$ 941.4	$ 875.7
Selling, general and administrative	260.3	245.7	801.9	682.5
Operating income	466.8	448.5	1,491.6	1,355.3
Interest expense, net	(56.4)	(53.1)	(160.5)	(150.2)
Other non-operating income (expense), net	2.4	0.5	18.3	3.2
Compensation-Retirement Benefits Accounting Standard [Member] | Previous Accounting Guidance [Member]
Income (Loss) from Continuing Operations before Income Taxes [Abstract]
Operating expenses	307.5	317.2	944.9	880.4
Selling, general and administrative	261.4	247.2	805.1	686.8
Operating income	464.5	445.4	1,484.9	1,346.3
Interest expense, net	(51.5)	(48.1)	(146)	(135.5)
Other non-operating income (expense), net	(0.2)	(1.4)	10.5	(2.5)
Compensation-Retirement Benefits Accounting Standard [Member] | Effect of Change [Member]
Income (Loss) from Continuing Operations before Income Taxes [Abstract]
Operating expenses	(1.2)	(1.6)	(3.5)	(4.7)
Selling, general and administrative	(1.1)	(1.5)	(3.2)	(4.3)
Operating income	2.3	3.1	6.7	9
Interest expense, net	(4.9)	(5)	(14.5)	(14.7)
Other non-operating income (expense), net	$ 2.6	$ 1.9	$ 7.8	$ 5.7

Description of Business and B_9

Description of Business and Basis of Presentation - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Item]
Number of Reportable Segments		2
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax	$ (2.2)		$ (2.2)
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Item]
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax		$ (2.3)
Accounting Standards Update 2016-01 [Member] | Series 2007-1 Notes [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Item]
Prepayment penalities of notes			$ 7.1

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
MA [Member]
Capitalized Contract Cost [Line Items]
Deferred Cost Balance	$ 93.3	$ 93.3
MA [Member] | Subscription and Maintenance Contracts [Member]
Capitalized Contract Cost [Line Items]
Contractual Coverage Period	1 year	1 year
MA [Member] | Minimum [Member] | Subscription and Maintenance Contracts [Member]
Capitalized Contract Cost [Line Items]
Contractual Coverage Period	3 years	3 years
Payment Terms		30 days
MA [Member] | Maximum [Member] | Subscription and Maintenance Contracts [Member]
Capitalized Contract Cost [Line Items]
Contractual Coverage Period	5 years	5 years
Payment Terms		60 days
MA [Member] | SG&A Expense [Member]
Capitalized Contract Cost [Line Items]
Contract Cost Amortization	$ 8	$ 24.7
MA [Member] | Royalty Cost [Member]
Capitalized Contract Cost [Line Items]
Deferred Cost Balance	24.8	24.8
MA [Member] | Royalty Cost [Member] | Operating Expense [Member]
Capitalized Contract Cost [Line Items]
Contract Cost Amortization	12.9	41.2
MIS [Member] | Capitalization of Work-In-Process for In-Progress Ratings [Member]
Capitalized Contract Cost [Line Items]
Deferred Cost Balance	$ 10.6	$ 10.6
MIS [Member] | Capitalization of Work-In-Process for In-Progress Ratings [Member] | Monitoring of Issuers or Issued Securities [Member]
Capitalized Contract Cost [Line Items]
Contractual Coverage Period	1 year	1 year
MIS [Member] | Capitalization of Work-In-Process for In-Progress Ratings [Member] | Operating Expense [Member]
Capitalized Contract Cost [Line Items]
Contract Cost Amortization	$ 10.3	$ 29.8

Revenues - Revenue by Category

Revenues - Revenue by Category (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	(34.2)	(33.1)	(102)	(93.6)
MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	644.8	694.2	2,117	2,049.1
MIS [Member] | Operating Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	676.4	723.2	2,209	2,131.1
MIS [Member] | Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	31.6	29	92	82
MIS [Member] | Corporate finance (CFG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	296.1	350.2	1,051.4	1,058.8
MIS [Member] | Corporate finance (CFG) [Member] | Investment-grade [Member]
Disaggregation of Revenue [Line Items]
Revenues	51	78.5	199.4	235.2
MIS [Member] | Corporate finance (CFG) [Member] | High-yield [Member]
Disaggregation of Revenue [Line Items]
Revenues	38.3	62.9	154.8	189.8
MIS [Member] | Corporate finance (CFG) [Member] | Bank loans [Member]
Disaggregation of Revenue [Line Items]
Revenues	75.9	82.4	301.9	274.1
MIS [Member] | Corporate finance (CFG) [Member] | Other product lines [Member]
Disaggregation of Revenue [Line Items]
Revenues	130.9	126.4	395.3	359.7
MIS [Member] | Structured Finance (SFG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	125.4	128.3	396.7	347.7
MIS [Member] | Structured Finance (SFG) [Member] | Assets-backed Securities [Member]
Disaggregation of Revenue [Line Items]
Revenues	24.6	22.8	80.7	69.6
MIS [Member] | Structured Finance (SFG) [Member] | Residential Mortgage-backed Securities Product [Member]
Disaggregation of Revenue [Line Items]
Revenues	23.7	21.9	74.8	64.7
MIS [Member] | Structured Finance (SFG) [Member] | Commercial real estate finance [Member]
Disaggregation of Revenue [Line Items]
Revenues	25.9	37.5	90.7	96.7
MIS [Member] | Structured Finance (SFG) [Member] | Structured credit [Member]
Disaggregation of Revenue [Line Items]
Revenues	50.7	45.6	148.6	115.2
MIS [Member] | Structured Finance (SFG) [Member] | Other product lines [Member]
Disaggregation of Revenue [Line Items]
Revenues	0.5	0.5	1.9	1.5
MIS [Member] | Financial institutions (FIG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	119.5	102.1	354.4	316.8
MIS [Member] | Financial institutions (FIG) [Member] | Banking [Member]
Disaggregation of Revenue [Line Items]
Revenues	72.9	70.1	227.2	219.6
MIS [Member] | Financial institutions (FIG) [Member] | Insurance [Member]
Disaggregation of Revenue [Line Items]
Revenues	37.7	23.9	98.9	72.4
MIS [Member] | Financial institutions (FIG) [Member] | Managed investments [Member]
Disaggregation of Revenue [Line Items]
Revenues	5.5	4.6	18.4	15.6
MIS [Member] | Financial institutions (FIG) [Member] | Other product lines [Member]
Disaggregation of Revenue [Line Items]
Revenues	0.5	3.5	9.9	9.2
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member]
Disaggregation of Revenue [Line Items]
Revenues	99	109.2	300.3	312
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | Public finance/sovereign [Member]
Disaggregation of Revenue [Line Items]
Revenues	45.3	49.4	143.9	155.6
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | Project and infrastructure [Member]
Disaggregation of Revenue [Line Items]
Revenues	53.7	59.8	156.4	156.4
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | Other product lines [Member]
Disaggregation of Revenue [Line Items]
Revenues	3.4	3.5	9.9	9.2
MIS [Member] | Rating Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	640	689.8	2,102.8	2,035.3
MIS [Member] | MIS Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	4.8	4.4	14.2	13.8
MA [Member]
Disaggregation of Revenue [Line Items]
Revenues	436	368.7	1,265.6	989.5
MA [Member] | Operating Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	438.6	372.8	1,275.6	1,001.1
MA [Member] | Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	2.6	4.1	10	11.6
MA [Member] | Research, Data And Analytics (RD&A) [Member]
Disaggregation of Revenue [Line Items]
Revenues	282.6	218.4	831.7	574.7
MA [Member] | Enterprise Risk Solutions (ERS) [Member]
Disaggregation of Revenue [Line Items]
Revenues	113	112.6	318.6	305.8
MA [Member] | Professional Services (PS) [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 40.4	$ 37.7	$ 115.3	$ 109

Revenues - Revenues disaggregat

Revenues - Revenues disaggregated by Line of Business and Geographical Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
U S
Disaggregation of Revenue [Line Items]
Revenues	559.6	588.4	1,782.7	1,734
International [Member]
Disaggregation of Revenue [Line Items]
Revenues	521.2	474.5	1,599.9	1,304.6
MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	644.8	694.2	2,117	2,049.1
MIS [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	384.7	427.7	1,269.3	1,262.6
MIS [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	260.1	266.5	847.7	786.5
MIS [Member] | Corporate finance (CFG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	296.1	350.2	1,051.4	1,058.8
MIS [Member] | Corporate finance (CFG) [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	184	234	673	698.6
MIS [Member] | Corporate finance (CFG) [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	112.1	116.2	378.4	360.2
MIS [Member] | Structured Finance (SFG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	125.4	128.3	396.7	347.7
MIS [Member] | Structured Finance (SFG) [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	81.3	89.3	259.2	235.9
MIS [Member] | Structured Finance (SFG) [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	44.1	39	137.5	111.8
MIS [Member] | Financial institutions (FIG) [Member]
Disaggregation of Revenue [Line Items]
Revenues	119.5	102.1	354.4	316.8
MIS [Member] | Financial institutions (FIG) [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	59.8	40.5	162.7	135
MIS [Member] | Financial institutions (FIG) [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	59.7	61.6	191.7	181.8
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member]
Disaggregation of Revenue [Line Items]
Revenues	99	109.2	300.3	312
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	59.4	63.8	173.9	192.8
MIS [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	39.6	45.4	126.4	119.2
MIS [Member] | Rating Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	640	689.8	2,102.8	2,035.3
MIS [Member] | Rating Revenue [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	384.5	427.6	1,268.8	1,262.3
MIS [Member] | Rating Revenue [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	255.5	262.2	834	773
MIS [Member] | MIS Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	4.8	4.4	14.2	13.8
MIS [Member] | MIS Other [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	0.2	0.1	0.5	0.3
MIS [Member] | MIS Other [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	4.6	4.3	13.7	13.5
MA [Member]
Disaggregation of Revenue [Line Items]
Revenues	436	368.7	1,265.6	989.5
MA [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	174.9	160.7	513.4	471.4
MA [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	261.1	208	752.2	518.1
MA [Member] | Research Data And Analytics [Member]
Disaggregation of Revenue [Line Items]
Revenues	282.6	218.4	831.7	574.7
MA [Member] | Research Data And Analytics [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	116.7	107.5	347.5	310.6
MA [Member] | Research Data And Analytics [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	165.9	110.9	484.2	264.1
MA [Member] | Enterprise Risk Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	113	112.6	318.6	305.8
MA [Member] | Enterprise Risk Solutions [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	43	39.5	124.1	120.1
MA [Member] | Enterprise Risk Solutions [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	70	73.1	194.5	185.7
MA [Member] | Professional Services [Member]
Disaggregation of Revenue [Line Items]
Revenues	40.4	37.7	115.3	109
MA [Member] | Professional Services [Member] | U S
Disaggregation of Revenue [Line Items]
Revenues	15.2	13.7	41.8	40.7
MA [Member] | Professional Services [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 25.2	$ 24	$ 73.5	$ 68.3

Revenues - Transaction and Rela

Revenues - Transaction and Relationship Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 644.8	$ 694.2	$ 2,117	$ 2,049.1
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
MA [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 436	$ 368.7	$ 1,265.6	$ 989.5
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
Corporate finance (CFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 296.1	$ 350.2	$ 1,051.4	$ 1,058.8
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
Structured Finance (SFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 125.4	$ 128.3	$ 396.7	$ 347.7
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
Financial institutions (FIG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 119.5	$ 102.1	$ 354.4	$ 316.8
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
Public, Project And Infrastructure Finance (PPIF) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 99	$ 109.2	$ 300.3	$ 312
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
MIS Other [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 4.8	$ 4.4	$ 14.2	$ 13.8
Percentage of Revenues	100.00%	100.00%	100.00%	100.00%
Transaction Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 461.5	$ 528.1	$ 1,547.7	$ 1,535.6
Percentage of Revenues	43.00%	50.00%	46.00%	51.00%
Transaction Revenue [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 390.5	$ 450.5	$ 1,349.4	$ 1,330.6
Percentage of Revenues	61.00%	65.00%	64.00%	65.00%
Transaction Revenue [Member] | MA [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 71	$ 77.6	$ 198.3	$ 205
Percentage of Revenues	16.00%	21.00%	16.00%	21.00%
Transaction Revenue [Member] | Corporate finance (CFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 192	$ 254.3	$ 741.2	$ 777.4
Percentage of Revenues	65.00%	73.00%	70.00%	73.00%
Transaction Revenue [Member] | Structured Finance (SFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 81	$ 84.1	$ 259.4	$ 216.8
Percentage of Revenues	65.00%	66.00%	65.00%	62.00%
Transaction Revenue [Member] | Financial institutions (FIG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 56.2	$ 40.6	$ 162.4	$ 137.9
Percentage of Revenues	47.00%	40.00%	46.00%	44.00%
Transaction Revenue [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 60.8	$ 71.1	$ 184.9	$ 197.5
Percentage of Revenues	61.00%	65.00%	62.00%	63.00%
Transaction Revenue [Member] | MIS Other [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 0.5	$ 0.4	$ 1.5	$ 1
Percentage of Revenues	10.00%	9.00%	11.00%	7.00%
Relationship Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 619.3	$ 534.8	$ 1,834.9	$ 1,503
Percentage of Revenues	57.00%	50.00%	54.00%	49.00%
Relationship Revenue [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 254.3	$ 243.7	$ 767.6	$ 718.5
Percentage of Revenues	39.00%	35.00%	36.00%	35.00%
Relationship Revenue [Member] | MA [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 365	$ 291.1	$ 1,067.3	$ 784.5
Percentage of Revenues	84.00%	79.00%	84.00%	79.00%
Relationship Revenue [Member] | Corporate finance (CFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 104.1	$ 95.9	$ 310.2	$ 281.4
Percentage of Revenues	35.00%	27.00%	30.00%	27.00%
Relationship Revenue [Member] | Structured Finance (SFG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 44.4	$ 44.2	$ 137.3	$ 130.9
Percentage of Revenues	35.00%	34.00%	35.00%	38.00%
Relationship Revenue [Member] | Financial institutions (FIG) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 63.3	$ 61.5	$ 192	$ 178.9
Percentage of Revenues	53.00%	60.00%	54.00%	56.00%
Relationship Revenue [Member] | Public, Project And Infrastructure Finance (PPIF) [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 38.2	$ 38.1	$ 115.4	$ 114.5
Percentage of Revenues	39.00%	35.00%	38.00%	37.00%
Relationship Revenue [Member] | MIS Other [Member] | MIS [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 4.3	$ 4	$ 12.7	$ 12.8
Percentage of Revenues	90.00%	91.00%	89.00%	93.00%

Revenues - Revenue Recognition

Revenues - Revenue Recognition Timing (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	$ 1,080.8	$ 3,382.6
At Point in Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	410	1,398.4
Over Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	670.8	1,984.2
Moodys Investors Service [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	644.8	2,117
Moodys Investors Service [Member] | At Point in Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	390.5	1,349.4
Moodys Investors Service [Member] | Over Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	254.3	767.6
Moodys Analytics [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	436	1,265.6
Moodys Analytics [Member] | At Point in Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	19.5	49
Moodys Analytics [Member] | Over Time [Member]
Change In Contract with Customer Liability [Abstract]
Revenue Recognized	$ 416.5	$ 1,216.6

Revenues - Schedule of Changes

Revenues - Schedule of Changes in the Deferred Revenue Balances (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Change In Contract with Customer Liability [Abstract]
Total Changes in deferred revenue		$ (35.3)	$ (19.3)
Deferred revenue - current	$ 771.5	771.5		$ 883.6
Deferred revenue - noncurrent	123.9	123.9		$ 140
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Change In Contract with Customer Liability [Abstract]
Beginning Balance	986.5	946.3
Revenue recognized that was included in the contract liability balance at the beginning of the period	(369.2)	(613.3)
Increases due to billings excluding amounts recognized as revenue during the period	278.2	577.5
Effect of exchange rate changes	(0.1)	(15.1)
Total Changes in deferred revenue	(91.1)	(50.9)
Ending Balance	895.4	895.4
MIS [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Change In Contract with Customer Liability [Abstract]
Beginning Balance	377.5	334.7
Revenue recognized that was included in the contract liability balance at the beginning of the period	(127.4)	(196.2)
Increases due to billings excluding amounts recognized as revenue during the period	101.6	217.6
Effect of exchange rate changes	1.1	(3.3)
Total Changes in deferred revenue	(24.7)	18.1
Ending Balance	352.8	352.8
Deferred revenue - current	233.9	233.9
Deferred revenue - noncurrent	118.9	118.9
MA [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Change In Contract with Customer Liability [Abstract]
Beginning Balance	609	611.6
Revenue recognized that was included in the contract liability balance at the beginning of the period	(241.8)	(417.1)
Increases due to billings excluding amounts recognized as revenue during the period	176.6	359.9
Effect of exchange rate changes	(1.2)	(11.8)
Total Changes in deferred revenue	(66.4)	(69)
Ending Balance	542.6	542.6
Deferred revenue - current	537.6	537.6
Deferred revenue - noncurrent	$ 5	$ 5

Revenues - Expected Recognition

Revenues - Expected Recognition Period for Remaining Performance Obligations (Detail) $ in Millions	Sep. 30, 2018USD ($)
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 151.3
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 22.4
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 68
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 43.2
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 7.5
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2033-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 4.2
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
MIS [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2038-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 6
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
MA [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 1,265.2
MA [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 930.1
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
MA [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 236.1
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
MA [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Disaggregation of Revenue [Line Items]
Remaining Performance Obligation	$ 99
Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Revenues - Additional Informati

Revenues - Additional Information (Detail) $ in Millions	Sep. 30, 2018USD ($)
MIS [Member]
Disaggregation of Revenue [Line Items]
Unbilled Receivables	$ 349.4
MA [Member]
Disaggregation of Revenue [Line Items]
Unbilled Receivables	$ 57

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Cost and Associated Tax Benefit (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Stock-based compensation expense	$ 30.5	$ 31.8	$ 100	$ 88.9
Tax benefit	$ 11.5	$ 10.3	$ 26	$ 28.8

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions used in Determining Fair Value for Options Granted (Detail)	9 Months Ended
	Sep. 30, 2018$ / shares
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected dividend yield	1.05%
Expected stock volatility	25.60%
Risk-free interest rate	2.81%
Expected holding period	6 years 2 months 12 days
Grant date fair value	$ 45.87

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Option Exercises and Restricted Stock Vesting (Detail) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Proceeds from stock option exercises	$ 36.2	$ 44
Aggregate intrinsic value	94.9	75.7
Tax benefit realized upon exercise	$ 23.2	$ 26.9
Number of shares exercised	0.8	1
Restricted Stock [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Fair value of shares vested	$ 150	$ 109.1
Tax benefit realized upon vesting	$ 34.7	$ 34.6
Number of shares vested	0.9	1
Vesting of Performance Based Restricted Stock [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Fair value of shares vested	$ 23	$ 19.5
Tax benefit realized upon vesting	$ 5.6	$ 6.9
Number of shares vested	0.1	0.2

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee stock options, granted | shares	0.2
Employee stock options, weighted average grant date fair value | $ / shares	$ 45.87
Employee Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period (in years)	4 years
Unrecognized compensation expense | $	$ 7.5
Weighted average period to recognize expense	2 years
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Other than options, Shares granted | shares	0.7
Other than options, weighted average grant date fair value | $ / shares	$ 167.48
Award vesting period (in years)	4 years
Unrecognized compensation expense | $	$ 164.6
Weighted average period to recognize expense	2 years 6 months
Performance Based Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Other than options, Shares granted | shares	0.1
Other than options, weighted average grant date fair value | $ / shares	$ 162.42
Award vesting period (in years)	3 years
Unrecognized compensation expense | $	$ 35.2
Weighted average period to recognize expense	1 year 9 months 18 days

Income Taxes - Income Taxes Pai

Income Taxes - Income Taxes Paid (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Income Taxes Paid, Net [Abstract]
Income Taxes Paid	$ 337	$ 194.7

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax - Additional Information [Abstract]
Effective tax rate	24.40%	31.40%	21.00%	29.00%
Overall increase (decrease) in unrecognized tax benefits (UTPs)	$ 73.5		$ 82.7
Excess Tax Benefit from Share Based Compensation			$ 37.5	$ 35.6
U.S. Statutory Tax Rate			35.00%		35.00%
Estimated Repatriation Tax Liability Resulting from Tax Reform Legislation			$ 247.3
U.S. Statutory Tax Rate, repatriation			21.00%
Estimated Deferred Tax Asset Resulting From Tax Act	54.4		$ 54.4
Reduction in Estimated Repatriation Tax Liability Resulting from Tax Act			10.3
Net of Federal Tax [Member]
Income Tax - Additional Information [Abstract]
Overall increase (decrease) in unrecognized tax benefits (UTPs)	$ 73.4		80.9
Revised Estimated Trasition Tax [Member]
Income Tax - Additional Information [Abstract]
Estimated Repatriation Tax Liability Resulting from Tax Reform Legislation			$ 237

Weighted Average Shares Outst_3

Weighted Average Shares Outstanding- Reconciliation of Basic to Diluted Shares Outstanding (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic	191.8	191.1	191.7	191.1
Dilutive effect of shares issuable under stock-based compensation plans	2.7	3	2.7	3
Diluted	194.5	194.1	194.4	194.1
Anti-dilutive options to purchase common shares and restricted stock as well as contingently issuable restricted stock which are excluded from the table above	0.3	0.5	0.4	0.6

Cash Equivalent and Investmen_3

Cash Equivalent and Investments (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Line Items]
Fair value	$ 34.7	$ 21.1
Cash and cash equivalents	1,034.8	1,071.5	$ 962.8	$ 2,051.5
Short-term investments	110.7	111.8
Money Market [Member]
Cash and Cash Equivalents [Line Items]
Cost	32.3	42.2
Fair value	32.3	42.2
Cash and cash equivalents	32.3	42.2
Certificates Of Deposit [Member]
Cash and Cash Equivalents [Line Items]
Cost	324	351.4
Fair value	324	351.4
Cash and cash equivalents	202.2	238.6
Short-term investments	110.7	111.8
Other assets	11.1	1
Fixed Maturity and Mutual Funds [Member]
Cash and Cash Equivalents [Line Items]
Cost	31.1	16.8
Gross unrealized gain	3.6	4.3
Fair value	34.7	21.1
Other assets	$ 34.7	$ 21.1

Cash Equivalent and Investmen_4

Cash Equivalent and Investments (Parenthetical) (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fixed Maturity and Mutual Funds [Member] | Minimum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period		6 months
Fixed Maturity and Mutual Funds [Member] | Maximum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period		7 months
Short Term Investments [Member] | Certificates Of Deposit [Member] | Minimum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period	1 month	1 month
Short Term Investments [Member] | Certificates Of Deposit [Member] | Maximum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period	12 months	12 months
Cash And Cash Equivalents [Member] | Maximum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period	90 days
Other Assets [Member] | Certificates Of Deposit [Member] | Minimum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period	13 months	15 months
Other Assets [Member] | Certificates Of Deposit [Member] | Maximum [Member]
Cash and Cash Equivalents [Line Items]
Securities Maturity period	39 months	48 months

Acquisitions - Purchase Price A

Acquisitions - Purchase Price Allocation (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Aug. 10, 2017	Dec. 31, 2016
Purchase Price Allocation [Abstract]
Indemnification asset	$ 15.8	$ 17
Goodwill	$ 3,661.3	$ 3,753.2		$ 1,023.6
Bureau van Dijk (BvD) [Member]
Purchase Price Allocation [Abstract]
Current assets			$ 158.4
Property and equipment, net			4.2
Total intangible assets			1,352.4
Goodwill			2,614.7
Other assets			5.9
Deferred revenue			(101.1)
Accounts payable and accrued liabilities			(44.3)
Deferred tax liabilities, net			(329.8)
Other liabilities			(118.4)
Liabilities assumed			(593.6)
Net assets acquired			3,542
Bureau van Dijk (BvD) [Member] | Customer Relationships [Member]
Purchase Price Allocation [Abstract]
Total intangible assets			998.7
Bureau van Dijk (BvD) [Member] | Product Technology [Member]
Purchase Price Allocation [Abstract]
Total intangible assets			258.5
Bureau van Dijk (BvD) [Member] | Trade Names [Member]
Purchase Price Allocation [Abstract]
Total intangible assets			82.3
Bureau van Dijk (BvD) [Member] | Databases [Member]
Purchase Price Allocation [Abstract]
Total intangible assets			$ 12.9

Acquisitions - Purchase Price_2

Acquisitions - Purchase Price Allocation (Parenthetical) (Detail) - Bureau van Dijk (BvD) [Member]	Aug. 10, 2017
Purchase Price Allocation [Abstract]
Weighted average life of intangible assets acquired (in years)	21 years
Customer Relationships [Member]
Purchase Price Allocation [Abstract]
Weighted average life of intangible assets acquired (in years)	23 years
Databases [Member]
Purchase Price Allocation [Abstract]
Weighted average life of intangible assets acquired (in years)	10 years
Product Technology [Member]
Purchase Price Allocation [Abstract]
Weighted average life of intangible assets acquired (in years)	12 years
Trade Names [Member]
Purchase Price Allocation [Abstract]
Weighted average life of intangible assets acquired (in years)	18 years

Acquisitions - BvD Pro Forma In

Acquisitions - BvD Pro Forma Information (Detail) - Bureau van Dijk (BvD) [Member] $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Business Acquisition ProForma Information [Abstract]
Proforma revenue	$ 3,226.9
Proforma net income from continuing operations	$ 965.9

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ in Millions	Aug. 10, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Aug. 13, 2018
Business Acquisition [Line Items]
Amortization expense		$ 24.6	$ 18.8	$ 75.4	$ 35.9
Remaining Reduction in Deferred Revenue to establish the fair value				1
Bureau van Dijk (BvD) [Member]
Business Acquisition [Line Items]
Business acquisition interests acquired	100.00%
Acquired cash included in current assets	$ 36
Account receivables gross included in current assets	88
Cash paid for acquisitions, net of cash required	3,542
Reduction in Deferred Revenue to establish the fair value	53	1		17
Allowance for Uncollectible Accounts	3.7
Amortization expense		$ 17.6		$ 54.2
Acquired Deferred Revenue	$ 154
Omega Performance [Member]
Business Acquisition [Line Items]
Business acquisition interests acquired						100.00%

Derivative Instruments And He_3

Derivative Instruments And Hedging Activities - Schedule of Interest Rate Swap (Details) - Interest Rate Swap (3-month LIBOR) [Member] - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
2010 Senior Notes [Member]
Derivative Instrument Detail [Abstract]
Hedged Item	2010 Senior Notes due 2020	2010 Senior Notes due 2020
Nature of Swap	Pay Floating/Receive Fixed	Pay Floating/Receive Fixed
Notional amount	$ 500	$ 500
Floating Interest Rate	3-month LIBOR	3-month LIBOR
2.75% 2017 Senior Notes, due 2021 [Member]
Derivative Instrument Detail [Abstract]
Hedged Item	2017 Senior Notes due 2021
Nature of Swap	Pay Floating/Receive Fixed
Notional amount	$ 500
Floating Interest Rate	3-month LIBOR
2014 Senior Notes (5-Year) [Member]
Derivative Instrument Detail [Abstract]
Hedged Item	2014 Senior Notes due 2019	2014 Senior Notes due 2019
Nature of Swap	Pay Floating/Receive Fixed	Pay Floating/Receive Fixed
Notional amount	$ 450	$ 450
Floating Interest Rate	3-month LIBOR	3-month LIBOR
2012 Senior Notes [Member]
Derivative Instrument Detail [Abstract]
Hedged Item	2012 Senior Notes due 2022	2012 Senior Notes due 2022
Nature of Swap	Pay Floating/Receive Fixed	Pay Floating/Receive Fixed
Notional amount	$ 80	$ 80
Floating Interest Rate	3-month LIBOR	3-month LIBOR

Derivative Instruments And He_4

Derivative Instruments And Hedging Activities - Summary of Net Gain (Loss) on Interest Rate Swaps Designated in Fair Value Hedge (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Summary of Fair Value Hedge Activity [Abstract]
Interest expense, net	$ (56.4)	$ (53.1)	$ (160.5)	$ (150.2)
Designated As Hedging Instrument [Member] | Interest Rate Swap [Member] | Interest Expense [Member]
Summary of Fair Value Hedge Activity [Abstract]
Fair value changes on interest rate swaps	(3.3)	(2.3)	(14.8)	(2.2)
Fair value changes on hedged debt	3.3	2.3	14.8	2.2
Designated As Hedging Instrument [Member] | Interest Rate Swap [Member] | Interest Expense [Member] | Fair Value hedge Net Interest Settlements and Accruals [Member]
Summary of Fair Value Hedge Activity [Abstract]
Amount of gain (loss) recognized in income	$ (0.5)	$ 1.6	$ (1)	$ 5.8

Derivative Instruments And He_5

Derivative Instruments And Hedging Activities - Gains (Losses) Recognized in AOCI and Reclassified from AOCI on Derivatives (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	$ 4	$ (6.7)	$ 22	$ (24)
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0.1	2.6	0.3	6.8
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	4.1		6.2	0.4
Net Investment Hedging [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	4	(9.9)	20.5	(30.2)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	4.1		6.2
Net Investment Hedging [Member] | Foreign Exchange Forward [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax		0.4		1.2
Net Investment Hedging [Member] | Long Term Debt [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	2.2	(10.3)	14.7	(31.4)
Net Investment Hedging [Member] | Cross-Currency Swap [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	1.8		5.8
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	4.1		6.2
Cash Flow Hedging [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax		3.2	1.5	6.2
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0.1	2.6	0.3	6.8
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)				0.4
Cash Flow Hedging [Member] | Cross-Currency Swap [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax		3.2	1.5	6.6
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	$ 0.1	$ 2.6	$ 0.3	7.9
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)				0.4
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax				(0.4)
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax				$ (1.1)

Derivative Instruments And He_6

Derivative Instruments And Hedging Activities - Gains (Losses) Recognized in AOCI and Reclassified from AOCI on Derivatives (Effective Portion) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Gains on cash flow hedges - Pre Tax	$ 0.1	$ 4.2	$ 0.3	$ 11.7
Other Comprehensive Income Loss Reclassification Adjustment From AOCI On Derivatives Tax		(1.6)		(4.9)
Currency Swap [Member] | Other Nonoperating Income (Expense) [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Gains on cash flow hedges - Pre Tax		3.5		12.1
Cash Flow Hedging [Member] | Currency Swap [Member] | Other Nonoperating Income (Expense) [Member]
Gains and Losses on Derivatives Designated as Hedging Instruments [Abstract]
Gains on cash flow hedges - Pre Tax		4.2		12.8
Other Comprehensive Income Loss Reclassification Adjustment From AOCI On Derivatives Tax		$ 1.6		$ 4.9

Derivative Instruments And He_7

Derivative Instruments And Hedging Activities - Cumulative Amount of Unrecognized Hedge Losses Recorded in AOCI (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 21.4	$ (0.3)
Net Investment Hedging [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	19.3	(1.2)
Net Investment Hedging [Member] | Foreign Exchange Forward [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	23.5	23.5
Net Investment Hedging [Member] | Long-Term Debt [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	(10)	(24.7)
Net Investment Hedging [Member] | Cross-Currency Swap [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	5.8
Cash Flow Hedging [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	2.1	0.9
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	(0.4)	(0.4)
Cash Flow Hedging [Member] | Cross-Currency Swap [Member]
Cumulative Amount of Unrecognized Hedge Losses Recorded In Accumulated Other Comprehensive Income [Abstract]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 2.5	$ 1.3

Derivative Instruments And He_8

Derivative Instruments And Hedging Activities - Summary of Notional Amounts of Outstanding Foreign Exchange Forwards, Cash Flow Hedging (Detail) € in Millions, ¥ in Millions, £ in Millions, $ in Millions, $ in Millions, $ in Millions	Sep. 30, 2018CAD ($)	Sep. 30, 2018EUR (€)	Sep. 30, 2018GBP (£)	Sep. 30, 2018JPY (¥)	Sep. 30, 2018USD ($)	Dec. 31, 2017CAD ($)	Dec. 31, 2017EUR (€)	Dec. 31, 2017GBP (£)	Dec. 31, 2017JPY (¥)	Dec. 31, 2017SGD ($)	Dec. 31, 2017USD ($)
Contracts to Sell US Dollars for GBP [Member] | Sell [Member]
Derivative Notional Amount [Abstract]
Notional amount					$ 556.8						$ 484.7
Contracts to Sell US Dollars for GBP [Member] | Buy [Member]
Derivative Notional Amount [Abstract]
Notional amount | £			£ 415.9					£ 362.3
Contracts to Sell USD for JPY [Member] | Sell [Member]
Derivative Notional Amount [Abstract]
Notional amount					25.5						24.3
Contracts to Sell USD for JPY [Member] | Buy [Member]
Derivative Notional Amount [Abstract]
Notional amount | ¥				¥ 2,700					¥ 2,700
Contracts to Sell USD for CAD [Member] | Sell [Member]
Derivative Notional Amount [Abstract]
Notional amount					85						51.7
Contracts to Sell USD for CAD [Member] | Buy [Member]
Derivative Notional Amount [Abstract]
Notional amount	$ 109					$ 64
Contracts to Sell US Dollars for Singapore dollars [Member] | Sell [Member]
Derivative Notional Amount [Abstract]
Notional amount											39.2
Contracts to Sell US Dollars for Singapore dollars [Member] | Buy [Member]
Derivative Notional Amount [Abstract]
Notional amount										$ 53
Contracts to Sell USD for Euros [Member] | Sell [Member]
Derivative Notional Amount [Abstract]
Notional amount					$ 200.8						$ 465.2
Contracts to Sell USD for Euros [Member] | Buy [Member]
Derivative Notional Amount [Abstract]
Notional amount | €		€ 169.9					€ 390

Derivative Instruments And He_9

Derivative Instruments And Hedging Activities - Summary of Net Gain (Loss) on Foreign Exchange Forwards Not Designated as Hedging Instruments (Detail) - Not Designated as Accounting Hedges [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Foreign Exchange Forwards Not Designated as Hedging Instruments [Abstract]
Amount of gain (loss) recognized in income	$ (11.8)	$ 79.1	$ (29.1)	$ 125.1
Foreign Exchange Forward [Member] | Other Nonoperating (Expense) Income [Member]
Foreign Exchange Forwards Not Designated as Hedging Instruments [Abstract]
Amount of gain (loss) recognized in income	$ (11.8)	9.2	$ (29.1)	14
Foreign Exchange Forward [Member] | Bureau van Dijk (BvD) [Member] | Purchase Price Hedge [Member]
Foreign Exchange Forwards Not Designated as Hedging Instruments [Abstract]
Amount of gain (loss) recognized in income		10.3		100.8
Foreign Exchange Collar [Member] | Bureau van Dijk (BvD) [Member] | Purchase Price Hedge [Member]
Foreign Exchange Forwards Not Designated as Hedging Instruments [Abstract]
Amount of gain (loss) recognized in income		$ 59.6		$ 10.3

Derivative Instruments And H_10

Derivative Instruments And Hedging Activities - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivative, Fair Value, Net [Abstract]
Assets	$ 10.3	$ 13
Liabilities	619	605.9
Long Term Debt [Member] | Net Investment Hedging [Member]
Derivative, Fair Value, Net [Abstract]
Liabilities	580.7	600.4
Derivatives Designated as Accounting Hedges [Member]
Derivative, Fair Value, Net [Abstract]
Assets	7.8	0.5
Liabilities	17.8	3.5
Derivatives Designated as Accounting Hedges [Member] | Interest Rate Swap [Member] | Other Assets [Member]
Derivative, Fair Value, Net [Abstract]
Assets		0.5
Derivatives Designated as Accounting Hedges [Member] | Interest Rate Swap [Member] | Other Noncurrent Liabilities [Member]
Derivative, Fair Value, Net [Abstract]
Liabilities	14	3.5
Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Other Current Assets [Member] | Net Investment Hedging [Member]
Derivative, Fair Value, Net [Abstract]
Assets	7.8
Not Designated as Accounting Hedges [Member] | Foreign Exchange Forward [Member] | Other Current Assets [Member]
Derivative, Fair Value, Net [Abstract]
Assets	2.5	12.5
Not Designated as Accounting Hedges [Member] | Foreign Exchange Forward [Member] | Accounts Payable And Accrued Liabilities [Member]
Derivative, Fair Value, Net [Abstract]
Liabilities	$ 20.5	$ 2

Derivative Instruments And H_11

Derivative Instruments And Hedging Activities - Additional Information (Detail) € in Millions, £ in Millions, $ in Millions	Sep. 30, 2018EUR (€)	Sep. 30, 2018GBP (£)	Sep. 30, 2018USD ($)	Dec. 31, 2017EUR (€)	Dec. 31, 2017GBP (£)	Dec. 31, 2017USD ($)	Aug. 10, 2017EUR (€)
Foreign Exchange Option [Member] | Cross-Currency Received [Member] | Bureau Van Dijk [Member] | Call Option [Member]
Derivative [Line Items]
Notional amount							€ 2,700
Foreign Exchange Option [Member] | Cross-Currency Received [Member] | Bureau Van Dijk [Member] | Put Option [Member]
Derivative [Line Items]
Notional amount							€ 2,700
Contracts to Sell US Dollars for GBP [Member] | Contract Sell [Member]
Derivative [Line Items]
Notional amount | $			$ 556.8			$ 484.7
Contracts to Sell US Dollars for GBP [Member] | Contract Buy [Member]
Derivative [Line Items]
Notional amount | £		£ 415.9			£ 362.3
Contracts to Sell US Dollars for GBP [Member] | Cross-Currency Paid [Member] | Bureau Van Dijk [Member] | Contract Sell [Member]
Derivative [Line Items]
Notional amount | $			41
Contracts to Sell US Dollars for GBP [Member] | Cross-Currency Received [Member] | Bureau Van Dijk [Member] | Contract Buy [Member]
Derivative [Line Items]
Notional amount | £		£ 31
Contracts to Sell USD for Euros [Member] | Contract Sell [Member]
Derivative [Line Items]
Notional amount | $			200.8			$ 465.2
Contracts to Sell USD for Euros [Member] | Contract Buy [Member]
Derivative [Line Items]
Notional amount	€ 169.9			€ 390
Contracts to Sell USD for Euros [Member] | Cross-Currency Paid [Member] | Bureau Van Dijk [Member] | Contract Sell [Member]
Derivative [Line Items]
Notional amount | $			2,800
Contracts to Sell USD for Euros [Member] | Cross-Currency Received [Member] | Bureau Van Dijk [Member] | Contract Buy [Member]
Derivative [Line Items]
Notional amount	2,400
Net Investment Hedging [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount	500
Net Investment Hedging [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Paid [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount | $			580
Net Investment Hedging [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Received [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount	€ 490.1
Cash Flow Hedging [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Paid [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount | $			$ 110.5
Derivative, swaption interest rate	3.945%	3.945%	3.945%
Cash Flow Hedging [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Received [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount	€ 100
Derivative, swaption interest rate	1.75%	1.75%	1.75%
2021 [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Paid [Member]
Derivative [Line Items]
Notional amount	€ 422.5
2022 [Member] | Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Cross-Currency Paid [Member]
Derivative [Line Items]
Notional amount	€ 67.6

Goodwill And Other Acquired I_3

Goodwill And Other Acquired Intangible Assets - Activity in Goodwill (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Activity In Goodwill [Abstract]
Beginning balance, Goodwill gross	$ 3,765.4	$ 1,035.8
Ending balance, Goodwill gross	3,673.5	3,765.4
Beginning balance, Accumulated impairment charge	(12.2)	(12.2)
Ending balance, Accumulated impairment charge	(12.2)	(12.2)
Beginning balance, goodwill net	3,753.2	1,023.6
Goodwill	23.8	2,622.6
Foreign currency translation adjustments	(115.7)	107
Ending balance, goodwill net	3,661.3	3,753.2
MIS [Member]
Activity In Goodwill [Abstract]
Beginning balance, Goodwill gross	285.2	277
Ending balance, Goodwill gross	272.1	285.2
Beginning balance, goodwill net	285.2	277
Foreign currency translation adjustments	(13.1)	8.2
Ending balance, goodwill net	272.1	285.2
MA [Member]
Activity In Goodwill [Abstract]
Beginning balance, Goodwill gross	3,480.2	758.8
Ending balance, Goodwill gross	3,401.4	3,480.2
Beginning balance, Accumulated impairment charge	(12.2)	(12.2)
Ending balance, Accumulated impairment charge	(12.2)	(12.2)
Beginning balance, goodwill net	3,468	746.6
Goodwill	23.8	2,622.6
Foreign currency translation adjustments	(102.6)	98.8
Ending balance, goodwill net	$ 3,389.2	$ 3,468

Goodwill And Other Acquired I_4

Goodwill And Other Acquired Intangible Assets - Acquired Intangible Assets and Related Amortization (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, net	$ 1,517.6	$ 1,631.6
Customer Relationships [Member]
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, gross	1,312.3	1,345.1
Accumulated amortization	(200.9)	(159.9)
Acquired intangible assets, net	1,111.4	1,185.2
Trade Secrets [Member]
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, gross	30.1	30.2
Accumulated amortization	(28.3)	(28.1)
Acquired intangible assets, net	1.8	2.1
Computer Software Intangible Asset [Member]
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, gross	348.8	358.6
Accumulated amortization	(96.2)	(78)
Acquired intangible assets, net	252.6	280.6
Trade Names [Member]
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, gross	156.4	161.6
Accumulated amortization	(33)	(26.7)
Acquired intangible assets, net	123.4	134.9
Other Intangible Assets [Member]
Intangible Assets and Related Amortization [Abstract]
Acquired intangible assets, gross	58.9	57.4
Accumulated amortization	(30.5)	(28.6)
Acquired intangible assets, net	$ 28.4	$ 28.8

Goodwill And Other Acquired I_5

Goodwill And Other Acquired Intangible Assets - Amortization Expense Relating to Acquired Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Amortization Expense Relating to Acquired Intangible Assets [Abstract]
Amortization expense	$ 24.6	$ 18.8	$ 75.4	$ 35.9

Goodwill And Other Acquired I_6

Goodwill And Other Acquired Intangible Assets - Estimated Future Amortization Expense for Acquired Intangible Assets Subject to Amortization (Detail) $ in Millions	Sep. 30, 2018USD ($)
Estimated Future Amortization Expense for Acquired Intangible Assets Subject to Amortization [Abstract]
2018 (after September 30)	$ 25.1
2,019	95.5
2,020	93.1
2,021	92.9
2,022	92.2
Thereafter	1,118.8
Total estimated future amortization	$ 1,517.6

Goodwill And Other Acquired I_7

Goodwill And Other Acquired Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Goodwill And Other Acquired Intangible Assets Additional Information [Abstract]
Impairments to intangible assets	$ 0	$ 0

Fair Value - Financial Instrume

Fair Value - Financial Instruments Carried at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets:
Derivative Contracts	$ 10.3	$ 13
Money market funds	32.3	42.2
Fixed maturity and open ended mutual funds	34.7	21.1
Total, Assets	77.3	76.3
Liabilities:
Derivatives, Liabilities	38.3	5.5
Total, Liabilities	38.3	5.5
Level 1 [Member]
Assets:
Money market funds	32.3	42.2
Fixed maturity and open ended mutual funds	34.7	21.1
Total, Assets	67	63.3
Level 2 [Member]
Assets:
Derivative Contracts	10.3	13
Total, Assets	10.3	13
Liabilities:
Derivatives, Liabilities	38.3	5.5
Total, Liabilities	$ 38.3	$ 5.5

Fair Value - Additional Informa

Fair Value - Additional Information (Detail)	Sep. 30, 2018USD ($)
Fair Value [Abstract]
Net asset stable value for public traded funds	$ 1

Other Balance Sheet and State_3

Other Balance Sheet and Statement of Operations Information - Additional Details Related to Certain Balance Sheet Captions (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Other current assets:
Prepaid taxes	$ 77.1	$ 94.9
Prepaid expenses	78.9	91.7
Capitalized costs to obtain and fulfill sales contracts	39.3	15.9
Other	43.6	47.6
Total other current assets	238.9	250.1
Other assets
Investments in joint ventures	98.3	99.1
Deposits for real-estate leases	13	12.3
Indemnification assets related to acquisitions	15.8	17
Mutual funds and fixed deposits	45.8	22.1
Costs to obtain sales contracts	68
Other	2.7	9.4
Total other assets	243.6	159.9
Accounts payable and accrued liabilities
Salaries and benefits	91.9	129.6
Incentive compensation	133.7	246.7
Customer credits, advanced payments and advanced billings	23.2	22.2
Self-insurance reserves	13.1	8.1
Dividends	5.6	6.2
Professional service fees	50.7	47.1
Interest accrued on debt	36.2	73.9
Accounts payable	16.2	21.8
Income taxes	79.9	79.2
Pension and other post retirement employee benefits	5.9	5.9
Accrued royalties	13.5	26.4
Foreign exchange forwards on certain assets and liabilities	20.5	2
Other	91.2	81.2
Total accounts payable and accrued liabilities	581.6	750.3
Other liabilities
Pension and other post retirement employee benefits	252.7	244.5
Deferred rent-non-current portion	96.6	103.1
Interest accrued on UTPs	65	54.7
Other tax matters	1.3	1.3
Income tax liability - non-current	122.6	232.2
Interest rate swaps	14	3.5
Other	22.7	24.7
Total other liabilities	$ 574.9	$ 664

Other Balance Sheet and State_4

Other Balance Sheet and Statement of Operations Information - Additional Details Related to Certain Balance Sheet Captions (Parenthetical) (Detail)	Sep. 30, 2018
Other assets
Capitalized Contract Cost Amortization Period	7 years

Other Balance Sheet and State_5

Other Balance Sheet and Statement of Operations Information- Changes in Self Insurance Reserves (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Changes in Self Insurance Reserves [Abstract]
Self-insurance reserves, beginning balance	$ 8.1	$ 11.1
Accruals (reversals), net	4.9	9.6
Payments	(0.1)	(12.6)
Self-insurance reserves, ending balance	$ 13.1	$ 8.1

Other Balance Sheet and State_6

Other Balance Sheet and Statement of Operations Information - Other Non-Operating Interest (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Nonoperating Income (Expense) [Abstract]
FX gain/(loss)	$ (3.9)	$ (6.7)	$ (3.6)	$ (12.5)
Net periodic pension costs - interest component	2.6	1.9	7.8	5.7
Joint venture income	3.3	2.7	9.2	7.7
Other	0.4	2.6	4.9	2.3
Total	$ 2.4	$ 0.5	$ 18.3	$ 3.2

Other Balance Sheet and State_7

Other Balance Sheet and Statement of Operations Information - Schedule of Minority Interest (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Schedule of Minority Interest [Abstract]
Beginning Balance			$ 212.8	$ 197.7	$ 197.7
Net Income	$ 1.8	$ 2.4	7.4	$ 4.1	7.1
Dividends			(4)		(3.3)
Purchase of noncontrolling interest					(1)
Non-controlling interests portion of foreign currency translation adjustments			(10.2)		13
Net realized and unrealized gain on available for sale securities					(0.7)
Ending Balance	$ 206		$ 206		$ 212.8

Comprehensive Income And Accu_3

Comprehensive Income And Accumulated Other Comprehensive Income - Reclassification out of AOCI (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax	$ 0.1	$ 4.2	$ 0.3	$ 11.7
Gains on cash flow hedges - Tax		(1.6)		(4.9)
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0.1	2.6	0.3	6.8
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(1.1)	(2.1)	(3.5)	(6.4)
Amortization of actuarial losses and prior service costs included in net income - Tax	0.3	0.8	1	2.5
Amortization of actuarial losses and prior service costs included in net income - Net of Tax	(0.8)	(1.3)	(2.5)	(3.9)
Available for sale securities:
Reclassification of gains included in net income - Pre Tax		2.2		2.2
Gains on available for sale securities - Net of Tax		2.2		2.2
(Losses) Income Attributable to Reclassification Out Of AOCI Net Of Tax	(0.7)	2.4	(2.2)	4
Parent [Member]
Available for sale securities:
Gains on available for sale securities - Net of Tax		1.1		1.1
Operating Expense [Member]
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(0.6)	(1.3)	(2.2)	(4)
Other Nonoperating Income (Expense) [Member] | Parent [Member]
Available for sale securities:
Reclassification of gains included in net income - Pre Tax		1.1		1.1
SG&A Expense [Member]
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(0.5)	(0.8)	(1.3)	(2.4)
Currency Swap [Member] | Interest Expense [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax	$ 0.1		$ 0.3
Currency Swap [Member] | Other Nonoperating Income (Expense) [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax		3.5		12.1
Treasury Rate Lock [Member] | Interest Expense [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax		$ 0.7		$ (0.4)

Comprehensive Income And Accu_4

Comprehensive Income And Accumulated Other Comprehensive Income - Changes in Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income [Abstract]
Beginning Balance	$ (304.8)	$ (309.7)	$ (172.2)	$ (364.9)
Pension and other retirement benefit plans before reclassification - Net of Tax			1.2	4.9
Reclassification adjustment from AOCI, Pension and Other Postretirement Benefit Plans - Net of Tax	0.8	1.3	2.5	3.9
Pension and other retirement benefit - Net of Tax	0.8	1.3	3.7	8.8
Net unrealized gain (losses) on cash flow - Net of Tax	4	(6.7)	22	(24)
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(0.1)	(2.6)	(0.3)	(6.8)
Foreign currency translation adjustments before reclassification - Net of Tax	(48.3)	51.8	(182.6)	114.4
Available for sale securities before reclassification - Net of Tax		0.5		1.6
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax		(2.2)		(2.2)
Amounts reclassified from AOCI	0.7	(2.4)	2.2	(4)
Total other comprehensive (loss) income - Net of Tax	(47.6)	52	(177.7)	122
Ending Balance	(342)	(257.8)	(342)	(257.8)
Parent [Member]
Accumulated Other Comprehensive Income [Abstract]
Foreign currency translation adjustments before reclassification - Net of Tax	(37.9)	50.8	(172.4)	99.2
Foreign currency translation adjustments - Net of Tax	(37.9)	50.8	(172.4)	99.2
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax		(1.1)		(1.1)
Gains on Available for sale securities - Net of Tax		(0.8)		(0.3)
Other comprehensive income/(loss) before reclassifications	(37.9)	54.3	(169.7)	111.1
Total other comprehensive (loss) income - Net of Tax	(37.2)	51.9	(169.8)	107.1
Financial Instruments - Overall (ASU 2016-01) [Member]
Accumulated Other Comprehensive Income [Abstract]
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax			(2.3)
Gains on Available for sale securities - Net of Tax			(2.3)
Amounts reclassified from AOCI			(2.3)
Pension and Other Retirement Benefits [Member]
Accumulated Other Comprehensive Income [Abstract]
Beginning Balance	(58.6)	(72)	(61.5)	(79.5)
Ending Balance	(57.8)	(70.7)	(57.8)	(70.7)
Gains (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income [Abstract]
Beginning Balance	2.2	0.5	0.9	1.7
Net unrealized gain (losses) on cash flow - Net of Tax		3.2	1.5	6.2
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(0.1)	(2.6)	(0.3)	(6.8)
Gains/(Losses) on cash flow hedges - Net of Tax	(0.1)	0.6	1.2	(0.6)
Ending Balance	2.1	1.1	2.1	1.1
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income [Abstract]
Beginning Balance	(248.4)	(241.8)	(113.9)	(290.2)
Ending Balance	(286.3)	(191)	(286.3)	(191)
Gains on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income [Abstract]
Beginning Balance		3.6	2.3	3.1
Ending Balance		$ 2.8		$ 2.8

Pension and Other Post-Retire_3

Pension and Other Post-Retirement Benefits - Components of Net Periodic Benefit Expense Related to Post-Retirement Plans (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Net Periodic Benefit Cost [Asbtract]
Interest cost	$ 4.9	$ 5	$ 14.5	$ 14.7
Pension Plans [Member]
Defined Benefit Plan Net Periodic Benefit Cost [Asbtract]
Service cost	4.6	4.6	14	13.8
Interest cost	4.4	4.7	13.2	13.9
Expected return on plan assets	(3.8)	(4.1)	(11.4)	(12.4)
Amortization of net actuarial loss from earlier periods	1.5	2.1	4.6	6.6
Amortization of net prior service costs from earlier periods			(0.2)
Net periodic expense	6.7	7.3	20.2	21.9
Other Retirement Plans [Member]
Defined Benefit Plan Net Periodic Benefit Cost [Asbtract]
Service cost	0.7	0.7	2.2	1.9
Interest cost	0.3	0.2	0.8	0.8
Amortization of net actuarial loss from earlier periods		0.1		0.1
Amortization of net prior service costs from earlier periods	(0.1)	(0.1)	(0.2)	(0.2)
Net periodic expense	$ 0.9	$ 0.9	$ 2.8	$ 2.6

Pension and Other Post-Retire_4

Pension and Other Post-Retirement Benefits - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Funded Pension Plans [Member]
Pension and Other Post-Retirement Benefits - Additional Information [Abstract]
Defined benefit payment amount	$ 15.6
Unfunded Pension Plans [Member]
Pension and Other Post-Retirement Benefits - Additional Information [Abstract]
Defined benefit payment amount	3.2
Estimated additional payments in 2018	2.1
Other Postretirement Benefit Plans Defined Benefit [Member]
Pension and Other Post-Retirement Benefits - Additional Information [Abstract]
Defined benefit payment amount	0.4
Estimated additional payments in 2018	$ 0.5

Indebtedness - Summary of Total

Indebtedness - Summary of Total Indebtedness (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Summary of Total Indebtedness [Abstract]
Principal Amount	$ 5,005.7	$ 5,580.4
Fair Value of Interest Rate Swap	(17.8)	(3)
Unamortized (Discount) Premium	(8.2)	(9.4)
Unamortized Debt Issuance Costs	(25.2)	(27.5)
Total Debt	4,954.5	5,540.5
Current portion	(470.5)	(429.4)
Carrying Amount	4,929.6	5,410.6
Current portion of long-term debt	(445.6)	(299.5)
Total long-term debt, non-current	4,484	5,111.1
Commercial Paper [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	25	130
Unamortized (Discount) Premium	(0.1)	(0.1)
Total Debt	24.9	129.9
5.50% 2010 Senior Notes, due 2020 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Fair Value of Interest Rate Swap	(8.3)
Unamortized (Discount) Premium	(0.7)	(1)
Unamortized Debt Issuance Costs	(0.8)	(1.2)
Carrying Amount	490.2	497.8
4.50% 2012 Senior Notes, due 2022 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Fair Value of Interest Rate Swap	(3.1)	(0.8)
Unamortized (Discount) Premium	(1.7)	(2)
Unamortized Debt Issuance Costs	(1.5)	(1.7)
Carrying Amount	493.7	495.5
4.875% 2013 Senior Notes, due 2024 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Unamortized (Discount) Premium	(1.6)	(1.8)
Unamortized Debt Issuance Costs	(2.1)	(2.4)
Carrying Amount	496.3	495.8
2.75% 2014 Senior Notes (5-Year), due 2019 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	450	450
Fair Value of Interest Rate Swap	(3.8)	(2.2)
Unamortized (Discount) Premium	(0.1)	(0.2)
Unamortized Debt Issuance Costs	(0.5)	(1.1)
Carrying Amount	445.6	446.5
5.25% 2014 Senior Notes (30-Year), due 2044 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	600	600
Unamortized (Discount) Premium	3.3	3.3
Unamortized Debt Issuance Costs	(5.5)	(5.7)
Carrying Amount	597.8	597.6
1.75% 2015 Senior Notes, due 2027 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	580.7	600.4
Unamortized Debt Issuance Costs	(3.2)	(3.6)
Carrying Amount	577.5	596.8
2.75% 2017 Senior Notes, due 2021 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Fair Value of Interest Rate Swap	(2.6)
Unamortized (Discount) Premium	(1.1)	(1.3)
Unamortized Debt Issuance Costs	(2.6)	(3.2)
Carrying Amount	493.7	495.5
2017 Floating Rate Senior Notes [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount		300
Unamortized Debt Issuance Costs		(0.5)
Carrying Amount		299.5
2.625% 2017 Notes, due 2023 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Unamortized (Discount) Premium	(0.9)	(1.1)
Unamortized Debt Issuance Costs	(3.1)	(3.5)
Carrying Amount	496	495.4
3.25% 2017 Notes, due 2028 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	500	500
Unamortized (Discount) Premium	(4.9)	(5.2)
Unamortized Debt Issuance Costs	(3.8)	(3.9)
Carrying Amount	491.3	490.9
2017 Term Loan Facility, due 2020 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	50	500
Unamortized Debt Issuance Costs	(0.5)	(0.7)
Carrying Amount	49.5	$ 499.3
3.25% 2018 Notes, due 2021 [Member]
Summary of Total Indebtedness [Abstract]
Principal Amount	300
Unamortized (Discount) Premium	(0.4)
Unamortized Debt Issuance Costs	(1.6)
Carrying Amount	$ 298

Indebtedness - Summary of Tot_2

Indebtedness - Summary of Total Indebtedness (Parenthetical) (Detail)	Sep. 30, 2018	Dec. 31, 2017
5.50% 2010 Senior Notes, due 2020 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	5.50%	5.50%
4.50% 2012 Senior Notes, due 2022 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	4.50%	4.50%
4.875% 2013 Senior Notes, due 2024 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	4.875%	4.875%
2.75% 2014 Senior Notes (5-Year), due 2019 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	2.75%	2.75%
5.25% 2014 Senior Notes (30-Year), due 2044 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	5.25%	5.25%
1.75% 2015 Senior Notes, due 2027 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	1.75%	1.75%
2.75% 2017 Senior Notes, due 2021 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	2.75%	2.75%
2.625% 2017 Notes, due 2023 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	2.625%	2.625%
3.25% 2017 Notes, due 2028 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	3.25%	3.25%
3.25% 2018 Notes, due 2021 [Member]
Summary of Total Indebtedness [Abstract]
Notes Payable, interest rate	3.25%

Indebtedness - Principal Paymen

Indebtedness - Principal Payments Due on Long-Term Borrowings (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Principal Payments Due on Long Term Borrowings [Abstract]
2018 (after September 30,)	$ 25
2,019	450
2,020	550
2,021	800
2,022	500
Thereafter	2,680.7
Total principal payment	5,005.7	$ 5,580.4
Commercial Paper [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2018 (after September 30,)	25
Total principal payment	25	130
2010 Senior Notes [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,020	500
Total principal payment	500	500
2012 Senior Notes [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,022	500
Total principal payment	500	500
2013 Senior Notes [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
Thereafter	500
Total principal payment	500	500
2014 Senior Notes (5-Year) [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,019	450
Total principal payment	450	450
2014 Senior Notes (30-Year) [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
Thereafter	600
Total principal payment	600	600
2015 Senior Notes [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
Thereafter	580.7
Total principal payment	580.7	600.4
2.75% 2017 Senior Notes, due 2021 [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,021	500
Total principal payment	500	500
2017 Term Loan Facility, due 2020 [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,020	50
Total principal payment	50	500
2.625% 2017 Notes, due 2023 [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
Thereafter	500
Total principal payment	500	500
3.25% 2017 Notes, due 2028 [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
Thereafter	500
Total principal payment	500	$ 500
3.25% 2018 Notes, due 2021 [Member]
Principal Payments Due on Long Term Borrowings [Abstract]
2,021	300
Total principal payment	$ 300

Indebtedness - Summary of Compo

Indebtedness - Summary of Components of Interest as Presented in Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Components of Interest as Presented in Consolidated Statements of Operations [Abstract]
Income	$ 4.1	$ 4.3	$ 10.7	$ 13
Expense on borrowings	(46.4)	(48.8)	(147.1)	(139.9)
Income (expense) on UTPs and other tax related liabilities	(9.6)	3.9	(10.6)	(9.4)
Net periodic pension costs - interest component	(4.9)	(5)	(14.5)	(14.7)
Capitalized	0.4	0.3	1	0.8
Total	$ (56.4)	$ (53.1)	$ (160.5)	$ (150.2)

Indebtedness - Interest Paid (D

Indebtedness - Interest Paid (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Interest Paid [Abstract]
Interest paid	$ 169.7	$ 136.2

Indebtedness - Fair Value and C

Indebtedness - Fair Value and Carrying Value of Long-Term Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	$ 4,929.6	$ 5,410.6
Estimated Fair Value	5,052.4	5,702.1
5.50% 2010 Senior Notes, due 2020 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	490.2	497.8
Estimated Fair Value	519.7	537.9
4.50% 2012 Senior Notes, due 2022 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	493.7	495.5
Estimated Fair Value	514.8	535.6
4.875% 2013 Senior Notes, due 2024 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	496.3	495.8
Estimated Fair Value	522.2	547.8
2.75% 2014 Senior Notes (5-Year), due 2019 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	445.6	446.5
Estimated Fair Value	449.4	452.8
5.25% 2014 Senior Notes (30-Year), due 2044 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	597.8	597.6
Estimated Fair Value	667.1	722.4
1.75% 2015 Senior Notes, due 2027 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	577.5	596.8
Estimated Fair Value	594.8	617.7
2.75% 2017 Senior Notes, due 2021 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	493.7	495.5
Estimated Fair Value	488.6	500
2017 Floating Rate Senior Notes [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt		299.5
Estimated Fair Value		300.2
2.625% 2017 Notes, due 2023 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	496	495.4
Estimated Fair Value	478.5	494.8
3.25% 2017 Notes, due 2028 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	491.3	490.9
Estimated Fair Value	469.1	493.6
2017 Term Loan Facility, due 2020 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	49.5	499.3
Estimated Fair Value	49.5	$ 499.3
3.25% 2018 Notes, due 2021 [Member]
Fair Value and Carrying Value of Long-Term Debt [Abstract]
Long term debt	298
Estimated Fair Value	$ 298.7

Indebtedness - Additional Infor

Indebtedness - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 5,005.7		$ 5,005.7	$ 5,580.4
Commercial Paper [Member]
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 25		$ 25
Commercial paper, interest rate	2.35%		2.35%
Maturity Date			5 days
Commercial Paper [Member] | Date of Issuance [Member]
Debt Instrument [Line Items]
Maturity Date			11 days
3.25% 2018 Notes, due 2021 [Member]
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 300		$ 300
Issuance Date of Debt			Jun. 1, 2018
Percentage of Principal Amount Being Prepaid Plus Accrued and Unpaid Interest			100.00%
Minimum Payment Percentage of Aggregate Principal Amount			25.00%
Minimum Aggregate Amount to be Paid on Maturity that Trips the Cross Default	$ 50		$ 50
Notes Payable, interest rate	3.25%		3.25%
Percentage of Principal Amount Plus Accrued and Unpaid Interest to the Date of Purchase			101.00%
Maturity date of Senior Unsecured Notes			Jun. 7, 2021
3.25% 2018 Notes, due 2021 [Member] | One Month Prior Maturity [Member]
Debt Instrument [Line Items]
Maturity date of Senior Unsecured Notes			May 7, 2021
2017 Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 50		$ 50
Repayments of Debt		$ 450
2017 Floating Rate Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 300

Contingencies - Additional Info

Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Contingencies [Abstract]
Unsupported Allegations of Minimum Underpaid Taxes	$ 120

Segment Information - Financial

Segment Information - Financial Information by Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financial Information by Segment [Abstract]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
Operating, SG&A	566.6	561.3	1,743.3	1,558.2
Adjusted Operating Income	514.2	501.6	1,639.3	1,480.4
Depreciation and amortization	46.1	43	143.6	108.4
Acquisition-Related Expenses	1.3	10.1	4.1	16.7
Operating Income	466.8	448.5	1,491.6	1,355.3
Eliminations [Member]
Financial Information by Segment [Abstract]
Revenues	(34.2)	(33.1)	(102)	(93.6)
Operating, SG&A	(34.2)	(33.1)	(102)	(93.6)
MIS [Member]
Financial Information by Segment [Abstract]
Revenues	644.8	694.2	2,117	2,049.1
MIS [Member] | Operating Segment [Member]
Financial Information by Segment [Abstract]
Revenues	676.4	723.2	2,209	2,131.1
Operating, SG&A	287.7	317.3	901.7	893.2
Adjusted Operating Income	388.7	405.9	1,307.3	1,237.9
Depreciation and amortization	15.8	18.6	49.3	56.4
Operating Income	372.9	387.3	1,258	1,181.5
MA [Member]
Financial Information by Segment [Abstract]
Revenues	436	368.7	1,265.6	989.5
MA [Member] | Operating Segment [Member]
Financial Information by Segment [Abstract]
Revenues	438.6	372.8	1,275.6	1,001.1
Operating, SG&A	313.1	277.1	943.6	758.6
Adjusted Operating Income	125.5	95.7	332	242.5
Depreciation and amortization	30.3	24.4	94.3	52
Acquisition-Related Expenses	1.3	10.1	4.1	16.7
Operating Income	$ 93.9	$ 61.2	$ 233.6	$ 173.8

Segment Information - Financi_2

Segment Information - Financial Information by Segment (Parenthetical) (Detail) - Compensation-Retirement Benefits Accounting Standard [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Moodys Investors Service [Member]
Financial Information by Segment [Abstract]
Reduction in Operating, SG&A	$ 1.9	$ 5.7
Moodys Analytics [Member]
Financial Information by Segment [Abstract]
Reduction in Operating, SG&A	$ 1.2	$ 3.3

Segment Information - Consolida

Segment Information - Consolidated Revenue Information by Geographic Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segments Geographical Areas [Abstract]
Revenues	$ 1,080.8	$ 1,062.9	$ 3,382.6	$ 3,038.6
United States [Member]
Segments Geographical Areas [Abstract]
Revenues	559.6	588.4	1,782.7	1,734
International [Member]
Segments Geographical Areas [Abstract]
Revenues	521.2	474.5	1,599.9	1,304.6
International [Member] | EMEA [Member]
Segments Geographical Areas [Abstract]
Revenues	344.5	291	1,047.9	779.3
International [Member] | Asia Pacific [Member]
Segments Geographical Areas [Abstract]
Revenues	123	118.6	366.9	336
International [Member] | Americas [Member]
Segments Geographical Areas [Abstract]
Revenues	$ 53.7	$ 64.9	$ 185.1	$ 189.3

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018
Segment Reporting Information [Line Items]
Operating Segments	2

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Oct. 26, 2018	Oct. 22, 2018	Oct. 15, 2018	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Cash paid for acquisitions, net of cash acquired					$ 35	$ 3,511
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend declared, per share		$ 0.44
Dividend declared, declaration date		Oct. 22, 2018
Dividend declared, payable date		Dec. 12, 2018
Dividend declared, record date		Nov. 21, 2018
Restructuring and Related Activities Completion Date	Jun. 30, 2019
Subsequent Event [Member] | Minimum [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	$ 45
Subsequent Event [Member] | Minimum [Member] | Real Estate Component [Member]
Subsequent Event [Line Items]
Restructuring, Settlement Charges				$ 20
Subsequent Event [Member] | Minimum [Member] | Restructuring Program [Member]
Subsequent Event [Line Items]
Effect on Future Earnings, Amount	30
Payments for Restructuring	25
Subsequent Event [Member] | Minimum [Member] | Q4, 2018 [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	30
Subsequent Event [Member] | Minimum [Member] | Q4, 2018 [Member] | Employee Severance [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	25
Subsequent Event [Member] | Maximum [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	60
Subsequent Event [Member] | Maximum [Member] | Real Estate Component [Member]
Subsequent Event [Line Items]
Restructuring, Settlement Charges				$ 25
Subsequent Event [Member] | Maximum [Member] | Restructuring Program [Member]
Subsequent Event [Line Items]
Effect on Future Earnings, Amount	40
Payments for Restructuring	35
Subsequent Event [Member] | Maximum [Member] | Q4, 2018 [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	40
Subsequent Event [Member] | Maximum [Member] | Q4, 2018 [Member] | Employee Severance [Member]
Subsequent Event [Line Items]
Restructuring Expected Cost	$ 35
Subsequent Event [Member] | Reis Inc [Member]
Subsequent Event [Line Items]
Cash paid for acquisitions, net of cash acquired			$ 278