Segment and Geographic Information - Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment information
Revenue	$ 1,735	$ 1,689	$ 1,704	$ 1,571	$ 1,536	$ 1,546	$ 1,609	$ 1,567	$ 6,699	$ 6,258	$ 6,063
Operating Profit	818	$ 891	$ 813	$ 705	704	$ 704	$ 672	$ 711	3,226	2,790	2,583
Amortization of intangibles									122	122	98
Pre-tax gain (loss) on dispositions									49
Depreciation & Amortization									204	206	180
Capital Expenditures									115	113	123
Total Assets	11,348				9,441				11,348	9,441
Assets held for sale	9				14				9	14
Operating segments
Segment information
Operating Profit									3,438	3,021	2,778
Depreciation & Amortization									162	167	171
Capital Expenditures									103	84	100
Total Assets	7,199				6,516				7,199	6,516
Corporate
Segment information
Revenue									0	15	0
Operating Profit									(212)	(231)	(195)
Employee severance charges									7	10	10
Amortization of intangibles									28	23
Non-cash acquisition and disposition-related costs/adjustments									21	31
Lease exit costs											19
Lease impairments									11	11
Depreciation & Amortization									42	39	9
Capital Expenditures									12	29	23
Total Assets	4,140				2,911				4,140	2,911
Intersegment Elimination
Segment information
Revenue									(128)	(125)	(110)
Ratings
Segment information
Employee severance charges									11	8	25
Legal settlement expenses										74	55
Amortization of intangibles									2	2	4
Ratings | Operating segments
Segment information
Revenue									3,106	2,883	2,988
Operating Profit									1,763	1,530	1,517
Depreciation & Amortization									34	32	34
Capital Expenditures									41	42	45
Total Assets	963				680				963	680
Market Intelligence
Segment information
Employee severance charges									6		7
Amortization of intangibles									75	73	71
Pre-tax gain (loss) on dispositions									22
Business disposition and employee severance charges										7
Acquisition-related costs									4
Non-cash acquisition and disposition-related costs/adjustments											4
Market Intelligence | Operating segments
Segment information
Revenue									1,959	1,833	1,683
Operating Profit									607	545	457
Depreciation & Amortization									99	99	104
Capital Expenditures									44	30	37
Total Assets	3,806				3,606				3,806	3,606
Platts
Segment information
Employee severance charges									1		2
Amortization of intangibles									12	18	18
Pre-tax gain (loss) on dispositions									27
Non-cash acquisition and disposition-related costs/adjustments											11
Lease exit costs											6
Asset write-off											2
Platts | Operating segments
Segment information
Revenue									844	815	774
Operating Profit									438	383	326
Depreciation & Amortization									21	27	25
Capital Expenditures									13	9	15
Total Assets	938				787				938	787
Indices
Segment information
Amortization of intangibles									6	6	6
Indices | Operating segments
Segment information
Revenue									918	837	728
Operating Profit									630	563	478
Depreciation & Amortization									8	9	8
Capital Expenditures									5	3	$ 3
Total Assets	$ 1,492				$ 1,443				$ 1,492	$ 1,443