Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,399	$ 1,439	$ 1,482	$ 1,341	$ 1,374	$ 1,324	$ 1,342	$ 1,273	$ 5,661	$ 5,313	$ 5,051
Operating profit	857	1,348	651	512	424	410	582	501	3,369	1,917	113
Net income (loss)	569	923	412	323	276	281	381	329	2,228	1,268	(13)
Net income attributable to S&P Global common shareholders	$ 537	$ 892	$ 383	$ 294	$ 248	$ 252	$ 353	$ 303	$ 2,106	$ 1,156	$ (115)
Net income (loss):
Basic (in dollars per share)	$ 2.07	$ 3.39	$ 1.45	$ 1.11	$ 0.92	$ 0.93	$ 1.29	$ 1.11	$ 8.02	$ 4.26	$ (0.42)
Diluted (in dollars per share)	$ 2.05	$ 3.36	$ 1.44	$ 1.10	$ 0.91	$ 0.92	$ 1.28	$ 1.10	$ 7.94	$ 4.21	$ (0.42)
Pre-tax gain (loss) on dispositions	$ 379	$ 722							$ 1,100
Gain (loss) on disposition of business, net of tax	$ 297	$ 521