Segment and Related Information - Operating Results by Segment (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 1,786	$ 1,571
Operating Profit	912	705
Amortization of intangibles from acquisitions	29	32
Gain on disposition	7	0
Operating Segments
Segment Reporting Information [Line Items]
Operating Profit	961	751
Operating Segments \| Ratings
Segment Reporting Information [Line Items]
Revenue	825	696
Operating Profit	520	368
Amortization of intangibles from acquisitions		1
Operating Segments \| Market Intelligence
Segment Reporting Information [Line Items]
Revenue	519	482
Operating Profit	147	134
Amortization of intangibles from acquisitions	19	18
Gain on disposition	7
Employee severance charges	2
Operating Segments \| Platts
Segment Reporting Information [Line Items]
Revenue	215	207
Operating Profit	112	99
Amortization of intangibles from acquisitions	2	3
Operating Segments \| Indices
Segment Reporting Information [Line Items]
Revenue	259	217
Operating Profit	182	150
Amortization of intangibles from acquisitions	1	1
Intersegment Elimination
Segment Reporting Information [Line Items]
Revenue	(32)	(31)
Corporate Unallocated
Segment Reporting Information [Line Items]
Operating Profit	(49)	(46)
Amortization of intangibles from acquisitions	7	8
Employee severance charges	7
Non-cash acquisition and disposition-related costs/adjustments	$ 5	$ 7

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