Condensed Consolidating Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Condensed Income Statements, Captions [Line Items]
Revenue	$ 1,943	$ 1,704	$ 3,729	$ 3,275
Expenses:
Operating-related expenses	493	471	1,014	944
Selling and general expenses	295	368	606	709
Depreciation	19	21	39	41
Amortization of intangibles	32	31	61	63
Total expenses	839	891	1,720	1,757
Gain on disposition	(1)	0	(8)	0
Operating profit	1,105	813	2,017	1,518
Other (income) expense, net	(10)	(6)	(9)	97
Interest expense, net	40	37	74	73
Non-operating intercompany transactions	0	0	0	0
Income before taxes on income	1,075	782	1,952	1,348
Provision for taxes on income	233	180	421	293
Equity in net income of subsidiaries	0	0	0	0
Net income	842	602	1,531	1,055
Less: net income attributable to noncontrolling interests	(50)	(47)	(100)	(90)
Net income attributable to S&P Global Inc.	792	555	1,431	965
Comprehensive income	798	584	1,451	1,146
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenue	(43)	(40)	(83)	(77)
Expenses:
Operating-related expenses	(41)	(40)	(81)	(77)
Selling and general expenses	(2)	0	(2)	0
Depreciation	0	0	0	0
Amortization of intangibles	0	0	0	0
Total expenses	(43)	(40)	(83)	(77)
Gain on disposition	0		0
Operating profit	0	0	0	0
Other (income) expense, net	0	0	0	0
Interest expense, net	0	0	0	0
Non-operating intercompany transactions	681	1,159	1,155	1,182
Income before taxes on income	(681)	(1,159)	(1,155)	(1,182)
Provision for taxes on income	0	0	0	0
Equity in net income of subsidiaries	(1,411)	(1,741)	(2,578)	(2,247)
Net income	(2,092)	(2,900)	(3,733)	(3,429)
Less: net income attributable to noncontrolling interests	(50)	(47)	(100)	(90)
Net income attributable to S&P Global Inc.	(2,142)	(2,947)	(3,833)	(3,519)
Comprehensive income	(2,091)	(2,900)	(3,733)	(3,430)
S&P Global Inc. | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	214	208	427	409
Expenses:
Operating-related expenses	26	65	57	131
Selling and general expenses	9	32	84	29
Depreciation	10	10	20	22
Amortization of intangibles	0	0	0	0
Total expenses	45	107	161	182
Gain on disposition	0		0
Operating profit	169	101	266	227
Other (income) expense, net	(3)	(5)	(8)	102
Interest expense, net	40	40	77	77
Non-operating intercompany transactions	95	95	198	191
Income before taxes on income	37	(29)	(1)	(143)
Provision for taxes on income	(25)	(3)	(9)	(43)
Equity in net income of subsidiaries	1,411	1,741	2,578	2,247
Net income	1,473	1,715	2,586	2,147
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	1,473	1,715	2,586	2,147
Comprehensive income	1,417	1,721	2,564	2,235
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	651	489	1,176	925
Expenses:
Operating-related expenses	108	110	226	227
Selling and general expenses	66	83	93	164
Depreciation	3	4	5	6
Amortization of intangibles	0	0	0	0
Total expenses	177	197	324	397
Gain on disposition	0		0
Operating profit	474	292	852	528
Other (income) expense, net	0	0	0	0
Interest expense, net	1	0	1	0
Non-operating intercompany transactions	(7)	(20)	(20)	(37)
Income before taxes on income	480	312	871	565
Provision for taxes on income	122	89	213	159
Equity in net income of subsidiaries	0	0	0	0
Net income	358	223	658	406
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	358	223	658	406
Comprehensive income	358	223	658	406
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	1,121	1,047	2,209	2,018
Expenses:
Operating-related expenses	400	336	812	663
Selling and general expenses	222	253	431	516
Depreciation	6	7	14	13
Amortization of intangibles	32	31	61	63
Total expenses	660	627	1,318	1,255
Gain on disposition	(1)		(8)
Operating profit	462	420	899	763
Other (income) expense, net	(7)	(1)	(1)	(5)
Interest expense, net	(1)	(3)	(4)	(4)
Non-operating intercompany transactions	(769)	(1,234)	(1,333)	(1,336)
Income before taxes on income	1,239	1,658	2,237	2,108
Provision for taxes on income	136	94	217	177
Equity in net income of subsidiaries	0	0	0	0
Net income	1,103	1,564	2,020	1,931
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	1,103	1,564	2,020	1,931
Comprehensive income	$ 1,114	$ 1,540	$ 1,962	$ 1,935