Consolidated Statement of Equity - USD ($) $ in Millions		Total	Total SPGI Equity	Common Stock $1 par	Additional Paid-in Capital	Retained Income	Accumulated Other Comprehensive Loss	Less: Treasury Stock	Noncontrolling Interests
Balance at beginning of period at Dec. 31, 2017		$ 768	$ 711	$ 412	$ 525	$ 10,025	$ (649)	$ (9,602)	$ 57
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	[1]	503	500			491	9		3
Dividends		(127)	(127)			(127)
Share repurchases		(1,100)	(1,100)		(150)			950
Employee stock plans		(24)	(25)		(40)			(15)	1
Change in redemption value of redeemable noncontrolling interest		9	9			9
Other	[2]	36	36			26	10
Balance at end of period at Mar. 31, 2018		65	4	412	335	10,424	(630)	(10,537)	61
Balance at beginning of period at Dec. 31, 2018		684	628	294	833	11,284	(742)	(11,041)	56
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	[1]	522	519			410	109		3
Dividends		(141)	(141)			(141)
Share repurchases		(644)	(644)					644
Employee stock plans		(14)	(14)		(61)			(47)
Capital contribution from noncontrolling interest		(36)	(36)			(36)
Change in redemption value of redeemable noncontrolling interest		15	15			15
Other		2							2
Balance at end of period at Mar. 31, 2019		$ 388	$ 327	$ 294	$ 772	$ 11,532	$ (633)	$ (11,638)	$ 61

[1] Excludes $40 million attributable to our redeemable noncontrolling interest.

[2] Reflects opening balance sheet adjustments related to the adoption of the new revenue recognition standard and the reclassification of the unrealized loss on investments from Accumulated other comprehensive loss to Retained income.