Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 3,535	$ 2,989
Acquisitions	50	565
Dispositions	(15)
Reclassifications	0
Other	5	(19)
Goodwill, ending balance	3,575	3,535
Operating Segments
Goodwill [Roll Forward]
Reclassifications	0
Operating Segments | Ratings
Goodwill [Roll Forward]
Goodwill, beginning balance	113	114
Acquisitions	0	5
Dispositions	0
Reclassifications	0
Other	2	(6)
Goodwill, ending balance	115	113
Operating Segments | Market Intelligence
Goodwill [Roll Forward]
Goodwill, beginning balance	2,029	1,961
Acquisitions	44	62
Dispositions	(12)
Reclassifications	3
Other	(2)	6
Goodwill, ending balance	2,062	2,029
Operating Segments | Platts
Goodwill [Roll Forward]
Goodwill, beginning balance	516	523
Acquisitions	6	0
Dispositions	(3)
Other	2	(7)
Goodwill, ending balance	521	516
Operating Segments | Indices
Goodwill [Roll Forward]
Goodwill, beginning balance	379	391
Acquisitions	0	0
Dispositions	0
Reclassifications	(3)
Other	0	(12)
Goodwill, ending balance	376	379
Corporate
Goodwill [Roll Forward]
Goodwill, beginning balance	498	0
Acquisitions	0	498
Dispositions	0
Reclassifications	0
Other	3	0
Goodwill, ending balance	$ 501	$ 498