Earnings Per Share - Schedule of Calculation for Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Amounts attributable to S&P Global Inc. common shareholders:
Net income	$ 972	$ 798	$ 2,207	$ 1,553
Basic weighted-average number of common shares outstanding (shares)	338,000,000.0	240,800,000	306,800,000	240,700,000
Effect of stock options and other dilutive securities (shares)	1,300,000	1,000,000.0	1,200,000	1,100,000
Diluted weighted-average number of common shares outstanding (shares)	339,300,000	241,800,000	308,000,000.0	241,700,000
Net income: Basic (USD per share)	$ 2.87	$ 3.31	$ 7.19	$ 6.45
Net income: Diluted (USD per share)	$ 2.86	$ 3.30	$ 7.17	$ 6.42
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings (shares)	0	0	0	0
Restricted Stock and Unit Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings (shares)			600,000	500,000