Nature of Operations and Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying unaudited financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Therefore, the financial statements included herein should be read in conjunction with the financial statements and notes included in our Form 10-K for the year ended December 31, 2016 (our “Form 10-K”). Certain prior-year amounts have been reclassified to conform with current presentation. In the opinion of management, all normal recurring adjustments considered necessary for a fair statement of the results of the interim periods have been included. The operating results for the three and nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the full year.
Use of Estimates	On an ongoing basis, we evaluate our estimates and assumptions, including those related to revenue recognition, allowance for doubtful accounts, valuation of long-lived assets, goodwill and other intangible assets, pension plans, incentive compensation and stock-based compensation, income taxes, contingencies and redeemable noncontrolling interests.
Recently Issued or Adopted Accounting Standards	In August of 2017, FASB issued guidance to enhance the hedge accounting model for both nonfinancial and financial risk components, which includes amendments to address certain aspects of recognition and presentation disclosure. The guidance is effective for reporting periods beginning after December 15, 2018. We do not expect this guidance to have a significant impact on our consolidated financial instruments. In May of 2017, FASB issued guidance that provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award. This guidance does not change the accounting for modifications but clarifies when modification accounting guidance should be applied. Under the new guidance, an entity should apply modification accounting in response to a change in the terms and conditions of an entity's share-based payment awards unless three newly specified criteria are met. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements. In March of 2017, FASB issued guidance to enhance the presentation of net periodic pension cost and net periodic postretirement benefit cost. The guidance requires employers to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period, and requires the other components of net periodic pension cost and net periodic postretirement benefit cost to be presented in the income statement separately from the service cost component outside a subtotal of income from operations, if one is presented. Additionally, only the service cost component is eligible for capitalization, when applicable. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We are currently assessing the impact of this guidance on our consolidated financial statements. In January of 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill and eliminates Step 2 from the goodwill impairment test. Under the new guidance, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The guidance is effective for reporting periods beginning after December 15, 2019; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements. In January of 2017, the FASB issued guidance that clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The guidance is effective for reporting periods beginning after December 15, 2017. We do not expect this guidance to have a significant impact on our consolidated financial statements. In August of 2016, the FASB issued guidance providing amendments to eight specific statement of cash flows classification issues. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements. In March of 2016, the FASB issued guidance to modify several aspects of accounting for share-based payment transactions, including the accounting for income taxes, forfeitures, statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance requires recognizing excess tax benefits and deficiencies as income tax expense or benefit in the statement of income, instead of in equity. The guidance was effective on January 1, 2017 and was adopted as follows: 1) prospectively for the recognition of excess tax benefits and deficiencies in the tax provision, 2) retrospectively for the classification of excess tax benefits and deficiencies in the statement of cash flows, and 3) retrospectively for the classification of cash paid for shares withheld to satisfy employee taxes in the statement of cash flows. For the nine months ended September 30, 2017, excess tax benefits from share-based payments of $51 million were recognized as an income tax benefit in our consolidated statements of income and classified as an operating activity in our consolidated statements of cash flows. For the nine months ended September 30, 2016, we reclassified $31 million of excess tax benefits from share-based payments from a financing activity to an operating activity in our consolidated statements of cash flows. In addition, cash paid for shares withheld on the employees' behalf of $49 million was classified as a financing activity in our consolidated statements of cash flows for the nine months ended September 30, 2017. Cash paid for employee taxes of $55 million was reclassified from an operating activity to a financing activity in our consolidated statements of cash flows for the nine months ended September 30, 2016. In February of 2016, the FASB issued guidance that amends accounting for leases. Under the new guidance, a lessee will recognize assets and liabilities but will recognize expenses similar to current lease accounting. The guidance is effective for reporting periods beginning after December 15, 2018; however early adoption is permitted. The new guidance must be adopted using a modified retrospective approach to each prior reporting period presented with various optional practical expedients. We are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements. In January of 2016, the FASB issued guidance to enhance the reporting model for financial instruments, which includes amendments to address certain aspects of recognition, measurement, presentation and disclosure. The guidance is effective for reporting periods beginning after December 15, 2017. We do not expect this guidance to have a significant impact on our consolidated financial statements. In May of 2014, the FASB and the International Accounting Standards Board (“IASB”) issued jointly a converged standard on the recognition of revenue from contracts with customers, which is intended to improve the financial reporting of revenue and comparability of the top line in financial statements globally. The core principle of the new standard is for the recognition of revenue to depict the transfer of goods or services to customers in amounts that reflect the payment to which the company expects to be entitled in exchange for those goods or services. The new standard will also result in enhanced revenue disclosures, provide guidance for transactions that were not previously addressed comprehensively and improve guidance for multiple-element arrangements. In August of 2015, the FASB issued guidance deferring the effective date of the new revenue standard by one year. Subsequently, the FASB issued implementation guidance related to the new revenue standard, including the following: In March of 2016, the FASB issued guidance to clarify the implementation guidance on principal versus agent considerations; in April of 2016, the FASB clarified guidance on performance obligations and the licensing implementation guidance; in May of 2016, the FASB issued a practical expedient in response to identified implementation issues. The new guidance will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. We will use the modified retrospective transition method and are evaluating the impact that the adoption of this standard will have on our consolidated financial statements. We are continuing our evaluation of potential changes to our accounting policies, business processes, systems and internal controls to support the recognition and disclosure requirements under the new standard. At this point, we believe the new standard will have an impact on: 1) the accounting for certain long-term deferred revenue in our Ratings segment which may contain a financing component, 2) the accounting for fees for certain Ratings products that are currently recognized over time or at a point in time to match when the customer obtains control of the product, 3) the presentation of sales of certain of our jointly-owned products in or Market and Commodities Intelligence segment, revenue will be recognized on a gross rather than net basis, and 4) the capitalization of costs to obtain a contract and the related amortization period of those costs. We do not expect that these changes from the adoption of this standard will have a significant impact on our consolidated financial statements.

In August of 2017, FASB issued guidance to enhance the hedge accounting model for both nonfinancial and financial risk components, which includes amendments to address certain aspects of recognition and presentation disclosure. The guidance is effective for reporting periods beginning after December 15, 2018. We do not expect this guidance to have a significant impact on our consolidated financial instruments.

In May of 2017, FASB issued guidance that provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award. This guidance does not change the accounting for modifications but

clarifies when modification accounting guidance should be applied. Under the new guidance, an entity should apply modification accounting in response to a change in the terms and conditions of an entity's share-based payment awards unless three newly specified criteria are met. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements.

In March of 2017, FASB issued guidance to enhance the presentation of net periodic pension cost and net periodic postretirement benefit cost. The guidance requires employers to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period, and requires the other components of net periodic pension cost and net periodic postretirement benefit cost to be presented in the income statement separately from the service cost component outside a subtotal of income from operations, if one is presented. Additionally, only the service cost component is eligible for capitalization, when applicable. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We are currently assessing the impact of this guidance on our consolidated financial statements.

In January of 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill and eliminates Step 2 from the goodwill impairment test. Under the new guidance, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The guidance is effective for reporting periods beginning after December 15, 2019; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements.

In January of 2017, the FASB issued guidance that clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The guidance is effective for reporting periods beginning after December 15, 2017. We do not expect this guidance to have a significant impact on our consolidated financial statements.

In August of 2016, the FASB issued guidance providing amendments to eight specific statement of cash flows classification issues. The guidance is effective for reporting periods beginning after December 15, 2017; however, early adoption is permitted. We do not expect this guidance to have a significant impact on our consolidated financial statements.

In March of 2016, the FASB issued guidance to modify several aspects of accounting for share-based payment transactions, including the accounting for income taxes, forfeitures, statutory tax withholding requirements, as well as classification in the statement of cash flows. This guidance requires recognizing excess tax benefits and deficiencies as income tax expense or benefit in the statement of income, instead of in equity. The guidance was effective on January 1, 2017 and was adopted as follows: 1) prospectively for the recognition of excess tax benefits and deficiencies in the tax provision, 2) retrospectively for the classification of excess tax benefits and deficiencies in the statement of cash flows, and 3) retrospectively for the classification of cash paid for shares withheld to satisfy employee taxes in the statement of cash flows. For the nine months ended September 30, 2017, excess tax benefits from share-based payments of $51 million were recognized as an income tax benefit in our consolidated statements of income and classified as an operating activity in our consolidated statements of cash flows. For the nine months ended September 30, 2016, we reclassified $31 million of excess tax benefits from share-based payments from a financing activity to an operating activity in our consolidated statements of cash flows. In addition, cash paid for shares withheld on the employees' behalf of $49 million was classified as a financing activity in our consolidated statements of cash flows for the nine months ended September 30, 2017. Cash paid for employee taxes of $55 million was reclassified from an operating activity to a financing activity in our consolidated statements of cash flows for the nine months ended September 30, 2016.

In February of 2016, the FASB issued guidance that amends accounting for leases. Under the new guidance, a lessee will recognize assets and liabilities but will recognize expenses similar to current lease accounting. The guidance is effective for reporting periods beginning after December 15, 2018; however early adoption is permitted. The new guidance must be adopted using a modified retrospective approach to each prior reporting period presented with various optional practical expedients. We are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements.

In January of 2016, the FASB issued guidance to enhance the reporting model for financial instruments, which includes amendments to address certain aspects of recognition, measurement, presentation and disclosure. The guidance is effective for reporting periods beginning after December 15, 2017. We do not expect this guidance to have a significant impact on our consolidated financial statements.

In May of 2014, the FASB and the International Accounting Standards Board (“IASB”) issued jointly a converged standard on the recognition of revenue from contracts with customers, which is intended to improve the financial reporting of revenue and comparability of the top line in financial statements globally. The core principle of the new standard is for the recognition of revenue to depict the transfer of goods or services to customers in amounts that reflect the payment to which the company expects to be entitled in exchange for those goods or services. The new standard will also result in enhanced revenue disclosures, provide guidance for transactions that were not previously addressed comprehensively and improve guidance for multiple-element arrangements. In August of 2015, the FASB issued guidance deferring the effective date of the new revenue standard by one year. Subsequently, the FASB issued implementation guidance related to the new revenue standard, including the following: In March of 2016, the FASB issued guidance to clarify the implementation guidance on principal versus agent considerations; in April of 2016, the FASB clarified guidance on performance obligations and the licensing implementation guidance; in May of 2016, the FASB issued a practical expedient in response to identified implementation issues. The new guidance will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. We will use the modified retrospective transition method and are evaluating the impact that the adoption of this standard will have on our consolidated financial statements. We are continuing our evaluation of potential changes to our accounting policies, business processes, systems and internal controls to support the recognition and disclosure requirements under the new standard. At this point, we believe the new standard will have an impact on: 1) the accounting for certain long-term deferred revenue in our Ratings segment which may contain a financing component, 2) the accounting for fees for certain Ratings products that are currently recognized over time or at a point in time to match when the customer obtains control of the product, 3) the presentation of sales of certain of our jointly-owned products in or Market and Commodities Intelligence segment, revenue will be recognized on a gross rather than net basis, and 4) the capitalization of costs to obtain a contract and the related amortization period of those costs. We do not expect that these changes from the adoption of this standard will have a significant impact on our consolidated financial statements.