Condensed Consolidating Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Condensed Income Statements, Captions [Line Items]
Revenue	$ 1,846	$ 1,689	$ 5,575	$ 4,964
Expenses:
Operating-related expenses	519	480	1,533	1,460
Selling and general expenses	339	318	944	992
Depreciation	20	20	60	61
Amortization of intangibles	32	29	94	92
Total expenses	910	847	2,631	2,605
Gain on dispositions	(8)	(49)	(16)	(49)
Operating profit	944	891	2,960	2,408
Other (income) expense, net	(6)	8	(16)	104
Interest expense, net	35	32	109	105
Loss on extinguishment of debt	279	0	279	0
Non-operating intercompany transactions	0	0	0	0
Income before taxes on income	636	851	2,588	2,199
Provision for taxes on income	138	189	559	482
Equity in net income of subsidiaries	0	0	0	0
Net income	498	662	2,029	1,717
Less: net income attributable to noncontrolling interests	(43)	(45)	(144)	(135)
Net income attributable to S&P Global Inc.	455	617	1,885	1,582
Comprehensive income	525	628	1,976	1,775
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenue	(42)	(39)	(124)	(116)
Expenses:
Operating-related expenses	(44)	(39)	(124)	(116)
Selling and general expenses	2	0	0	0
Depreciation	0	0	0	0
Amortization of intangibles	0	0	0	0
Total expenses	(42)	(39)	(124)	(116)
Gain on dispositions	0		0	0
Operating profit	0	0	0	0
Other (income) expense, net	0	0	0	0
Interest expense, net	0	0	0	0
Loss on extinguishment of debt	0		0
Non-operating intercompany transactions	75	13	1,231	1,195
Income before taxes on income	(75)	(13)	(1,231)	(1,195)
Provision for taxes on income	0	0	0	0
Equity in net income of subsidiaries	(711)	(622)	(3,289)	(2,868)
Net income	(786)	(635)	(4,520)	(4,063)
Less: net income attributable to noncontrolling interests	(43)	(45)	(144)	(135)
Net income attributable to S&P Global Inc.	(829)	(680)	(4,664)	(4,198)
Comprehensive income	(789)	(633)	(4,522)	(4,062)
S&P Global Inc. | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	219	207	645	617
Expenses:
Operating-related expenses	28	64	85	195
Selling and general expenses	26	26	109	55
Depreciation	9	11	30	33
Amortization of intangibles	0	0	0	0
Total expenses	63	101	224	283
Gain on dispositions	(5)		(5)	(49)
Operating profit	161	155	426	383
Other (income) expense, net	(4)	(5)	(12)	96
Interest expense, net	35	37	112	115
Loss on extinguishment of debt	279		279
Non-operating intercompany transactions	103	100	300	291
Income before taxes on income	(252)	23	(253)	(119)
Provision for taxes on income	(71)	16	(80)	(28)
Equity in net income of subsidiaries	711	622	3,289	2,868
Net income	530	629	3,116	2,777
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	530	629	3,116	2,777
Comprehensive income	503	632	3,067	2,869
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	541	491	1,717	1,416
Expenses:
Operating-related expenses	120	103	345	330
Selling and general expenses	84	58	177	222
Depreciation	2	3	8	9
Amortization of intangibles	0	0	0	0
Total expenses	206	164	530	561
Gain on dispositions	0		0	0
Operating profit	335	327	1,187	855
Other (income) expense, net	0	0	0	0
Interest expense, net	1	0	1	0
Loss on extinguishment of debt	0		0
Non-operating intercompany transactions	(6)	(6)	(26)	(42)
Income before taxes on income	340	333	1,212	897
Provision for taxes on income	83	80	296	239
Equity in net income of subsidiaries	0	0	0	0
Net income	257	253	916	658
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	257	253	916	658
Comprehensive income	257	253	916	658
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue	1,128	1,030	3,337	3,047
Expenses:
Operating-related expenses	415	352	1,227	1,051
Selling and general expenses	227	234	658	715
Depreciation	9	6	22	19
Amortization of intangibles	32	29	94	92
Total expenses	683	621	2,001	1,877
Gain on dispositions	(3)		(11)	0
Operating profit	448	409	1,347	1,170
Other (income) expense, net	(2)	13	(4)	8
Interest expense, net	(1)	(5)	(4)	(10)
Loss on extinguishment of debt	0		0
Non-operating intercompany transactions	(172)	(107)	(1,505)	(1,444)
Income before taxes on income	623	508	2,860	2,616
Provision for taxes on income	126	93	343	271
Equity in net income of subsidiaries	0	0	0	0
Net income	497	415	2,517	2,345
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	497	415	2,517	2,345
Comprehensive income	$ 554	$ 376	$ 2,515	$ 2,310