Acquisitions and Divestitures - Components of Assets and Liabilities, and Operating Loss, of Businesses Held for Sale (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Assets and Liabilities of Business Held for Sale
Gain on disposition		$ 0	$ 722	$ 0	$ 722
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Operating Loss of Business Disposed of
Operating profit		$ 0	22	$ 0	29
Quant House SAS | Disposal Group, Held-for-sale, Not Discontinued Operations
Assets and Liabilities of Business Held for Sale
Accounts receivable, net						$ 4
Other assets						3
Assets of a business held for sale						7
Accounts payable and accrued expenses						3
Unearned revenue						7
Other liabilities						35
Liabilities of a business held for sale						$ 45
S&P Global Platts | J.D. Power | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Assets and Liabilities of Business Held for Sale
Proceeds from divestiture of businesses	$ 1,100
Gain on disposition			722		$ 722
Gain (loss) on disposition of business, net of Tax			$ 521