Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 689	$ 453
Other comprehensive income:
Foreign currency translation adjustments	(37)	17
Income tax effect	6	2
Foreign currency translation adjustment, net of income tax effect	(31)	19
Pension and other postretirement benefit plans	3	114
Income tax effect	(1)	(28)
Pension and other postretirement benefit plans, net of income tax effect	2	86
Unrealized (loss) gain on forward exchange contracts	(9)	5
Income tax effect	2	(1)
Unrealized gain on investment and forward exchange contracts, net of income tax effect	(7)	4
Comprehensive income	653	562
Less: comprehensive income attributable to nonredeemable noncontrolling interests	(1)	(3)
Less: comprehensive income attributable to redeemable noncontrolling interests	(49)	(40)
Comprehensive income attributable to S&P Global Inc.	$ 603	$ 519