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]	893	885			951	(66)		8
Dividends		(260)	(253)			(253)			(7)
Share repurchases		(1,100)	(1,100)		(150)			950
Employee stock plans		46	46		30			(16)
Change in redemption value of redeemable noncontrolling interest		(72)	(72)			(72)
Increase in CRISIL ownership		(26)	(25)		(25)				(1)
Stock consideration for Kensho		352	352		352
Other	[2]	32	36			26	10		(4)
Balance at end of period at Jun. 30, 2018		633	580	412	732	10,677	(705)	(10,536)	53
Balance at beginning of period at Mar. 31, 2018		65	4	412	335	10,424	(630)	(10,537)	61
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	[1]	391	386			461	(75)		5
Dividends		(133)	(126)			(126)			(7)
Share repurchases			0
Employee stock plans		70	71		70			(1)	(1)
Change in redemption value of redeemable noncontrolling interest		(82)	(82)			(82)
Increase in CRISIL ownership		(26)	(25)		(25)				(1)
Stock consideration for Kensho		352	352		352
Other		(4)							(4)
Balance at end of period at Jun. 30, 2018		633	580	412	732	10,677	(705)	(10,536)	53
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]	1,062	1,056			965	91		6
Dividends		(287)	(281)			(281)			(6)
Share repurchases		(644)	(644)					644
Employee stock plans		11	11		(43)			(54)
Capital contribution from noncontrolling interest		(222)	(222)			(222)
Change in redemption value of redeemable noncontrolling interest		(36)	(36)			(36)
Other		2							2
Balance at end of period at Jun. 30, 2019		570	512	294	790	11,710	(651)	(11,631)	58
Balance at beginning of period at Mar. 31, 2019		388	327	294	772	11,532	(633)	(11,638)	61
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	[1]	540	537			555	(18)		3
Dividends		(146)	(140)			(140)			(6)
Share repurchases			0
Employee stock plans		25	25		18			(7)
Capital contribution from noncontrolling interest		(237)	(237)			(237)
Balance at end of period at Jun. 30, 2019		$ 570	$ 512	$ 294	$ 790	$ 11,710	$ (651)	$ (11,631)	$ 58

[1] Excludes comprehensive income of $44 million and $36 million for the three months ended June 30, 2019 and 2018, respectively, and $84 million and $76 million for the six months ended June 30, 2019 and 2018, respectively, 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.