Equity (Schedule of stock repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares purchased (in shares)	0.3	1.4	1.6	3.5	2.6
Average price paid per share (in dollars per share)		$ 107.74	$ 104.82	$ 98.05	$ 104.62
Total cash utilized	$ 26			$ 346
Cash used to repurchase shares				373	$ 274
Stock Repurchases
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash used to repurchase shares				373
Total SPGI Equity
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total cash utilized		$ 147	$ 164	$ 347	$ 274