Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 1,735	$ 1,536	$ 6,699	$ 6,258	$ 6,063
Expenses:
Operating-related expenses			1,801	1,698	1,694
Selling and general expenses			1,517	1,564	1,606
Depreciation			82	84	82
Amortization of intangibles			122	122	98
Total expenses			3,522	3,468	3,480
Gain on dispositions			(49)	0	0
Operating profit	818	704	3,226	2,790	2,583
Other expense (income), net			98	(25)	(27)
Interest expense, net			198	134	149
Income before taxes on income			2,930	2,681	2,461
Provision for taxes on income			627	560	823
Net income	585	551	2,303	2,121	1,638
Less: net income attributable to noncontrolling interests			(180)	(163)	(142)
Net income attributable to S&P Global Inc.	$ 541	$ 512	$ 2,123	$ 1,958	$ 1,496
Net income:
Basic (USD per share)	$ 2.22	$ 2.06	$ 8.65	$ 7.80	$ 5.84
Diluted (USD per share)	$ 2.20	$ 2.03	$ 8.60	$ 7.73	$ 5.78
Weighted-average number of common shares outstanding:
Basic (shares)			245.4	250.9	256.3
Diluted (shares)			246.9	253.2	258.9
Actual shares outstanding at year end (shares)	244.0	248.4	244.0	248.4	253.7