Condensed Consolidating Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Income Statements, Captions [Line Items]
Revenue	$ 1,786	$ 1,571
Expenses:
Operating-related expenses	521	473
Selling and general expenses	311	341
Depreciation	20	20
Amortization of intangibles	29	32
Total expenses	881	866
Gain on disposition	(7)	0
Operating profit	912	705
Other expense, net	1	103
Interest expense, net	34	36
Non-operating intercompany transactions	0	0
Income before taxes on income	877	566
Provision for taxes on income	188	113
Equity in net income of subsidiaries	0	0
Net income	689	453
Less: net income attributable to noncontrolling interests	(50)	(43)
Net income attributable to S&P Global Inc.	639	410
Comprehensive income	653	562
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenue	(39)	(38)
Expenses:
Operating-related expenses	(39)	(38)
Selling and general expenses	0	0
Depreciation	0	0
Amortization of intangibles	0	0
Total expenses	(39)	(38)
Gain on disposition	0
Operating profit	0	0
Other expense, net	0	0
Interest expense, net	0	0
Non-operating intercompany transactions	474	23
Income before taxes on income	(474)	(23)
Provision for taxes on income	0	0
Equity in net income of subsidiaries	(1,168)	(506)
Net income	(1,642)	(529)
Less: net income attributable to noncontrolling interests	(50)	(43)
Net income attributable to S&P Global Inc.	(1,692)	(572)
Comprehensive income	(1,641)	(530)
S&P Global Inc. | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	212	202
Expenses:
Operating-related expenses	31	67
Selling and general expenses	74	(4)
Depreciation	11	11
Amortization of intangibles	0	0
Total expenses	116	74
Gain on disposition	0
Operating profit	96	128
Other expense, net	(5)	107
Interest expense, net	37	38
Non-operating intercompany transactions	103	96
Income before taxes on income	(39)	(113)
Provision for taxes on income	16	(40)
Equity in net income of subsidiaries	1,168	506
Net income	1,113	433
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to S&P Global Inc.	1,113	433
Comprehensive income	1,146	515
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	525	436
Expenses:
Operating-related expenses	117	117
Selling and general expenses	27	81
Depreciation	2	2
Amortization of intangibles	0	0
Total expenses	146	200
Gain on disposition	0
Operating profit	379	236
Other expense, net	0	0
Interest expense, net	0	0
Non-operating intercompany transactions	(13)	(16)
Income before taxes on income	392	252
Provision for taxes on income	91	70
Equity in net income of subsidiaries	0	0
Net income	301	182
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to S&P Global Inc.	301	182
Comprehensive income	301	182
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	1,088	971
Expenses:
Operating-related expenses	412	327
Selling and general expenses	210	264
Depreciation	7	7
Amortization of intangibles	29	32
Total expenses	658	630
Gain on disposition	(7)
Operating profit	437	341
Other expense, net	6	(4)
Interest expense, net	(3)	(2)
Non-operating intercompany transactions	(564)	(103)
Income before taxes on income	998	450
Provision for taxes on income	81	83
Equity in net income of subsidiaries	0	0
Net income	917	367
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to S&P Global Inc.	917	367
Comprehensive income	$ 847	$ 395