Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 452	$ 923	$ 1,339	$ 1,659
Other comprehensive income:
Foreign currency translation adjustment	24	(14)	96	(55)
Income tax effect	0	3	0	3
Foreign currency translation adjustment, net of income tax effect	24	(11)	96	(52)
Pension and other postretirement benefit plans	3	3	7	19
Income tax effect	(1)	(1)	0	(5)
Pension and other post-retirement benefit plans, net of income tax effect	2	2	7	14
Unrealized loss on investment	(8)	0	(10)	0
Income tax effect	0	0	0	0
Unrealized (loss) on investment, net of income tax effect	(8)	0	(10)	0
Unrealized gain on forward exchange contracts	4	1	3	4
Income tax effect	(1)	0	(1)	(1)
Unrealized gain on forward exchange contracts, net of income tax effect	3	1	2	3
Comprehensive income	473	915	1,434	1,624
Less: comprehensive income attributable to nonredeemable noncontrolling interests	(4)	(2)	(10)	(8)
Less: comprehensive income attributable to redeemable noncontrolling interests	(34)	(29)	(95)	(82)
Comprehensive income attributable to S&P Global Inc.	$ 435	$ 884	$ 1,329	$ 1,534