Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 1,513	$ 1,439	$ 4,475	$ 4,262
Expenses:
Operating-related expenses	421	431	1,282	1,352
Selling and general expenses	388	337	1,077	986
Depreciation	22	22	61	63
Amortization of intangibles	24	23	73	71
Total expenses	855	813	2,493	2,472
Gain on disposition	0	(722)	0	(722)
Operating profit	658	1,348	1,982	2,512
Interest expense, net	37	39	110	122
Income before taxes on income	621	1,309	1,872	2,390
Provision for taxes on income	169	386	533	731
Net income	452	923	1,339	1,659
Less: net income attributable to noncontrolling interests	(38)	(31)	(105)	(90)
Net income attributable to S&P Global Inc.	$ 414	$ 892	$ 1,234	$ 1,569
Net income:
Basic (in dollars per share)	$ 1.62	$ 3.39	$ 4.80	$ 5.94
Diluted (in dollars per share)	$ 1.61	$ 3.36	$ 4.75	$ 5.89
Weighted-average number of common shares outstanding:
Basic (in shares)	255.5	262.9	257.0	264.1
Diluted (in shares)	257.9	265.3	259.5	266.4
Actual shares outstanding at period end (in shares)			255.0	259.1
Dividend declared per common share (in dollars per share)	$ 0.41	$ 0.36	$ 1.23	$ 1.08