Acquisitions and Divestitures - Acquisitions Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2018	Jan. 31, 2018	Aug. 31, 2017	Jun. 30, 2017
Business Acquisition [Line Items]
Consideration paid for acquisition, net of cash acquired		$ 91	$ 401
Cash paid for acquisitions, net of cash acquired				$ 83
FiscalNote
Business Acquisition [Line Items]
Cost method investment ownership interest (as a percent)					5.03%
Kensho Technologies
Business Acquisition [Line Items]
Consideration paid for acquisition, net of cash acquired	$ 550
Pragmatix Services Private Limited
Business Acquisition [Line Items]
Ownership in equity method investment (as a percent)						100.00%
Algomi Limited
Business Acquisition [Line Items]
Cost method investment ownership interest (as a percent)							6.02%
CARE Ratings Limited
Business Acquisition [Line Items]
Cost method investment ownership interest (as a percent)								8.90%
Series of Individually Immaterial Business Acquisitions | Minimum
Business Acquisition [Line Items]
Amortization period of acquired intangible assets (in years)		3 years
Series of Individually Immaterial Business Acquisitions | Maximum
Business Acquisition [Line Items]
Amortization period of acquired intangible assets (in years)		10 years	10 years