Condensed Consolidating Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Income Statements, Captions [Line Items]
Revenue	$ 1,509	$ 1,482	$ 2,962	$ 2,823
Expenses:
Operating-related expenses	449	469	861	923
Selling and general expenses	338	317	689	650
Depreciation	20	22	39	40
Amortization of intangibles	25	23	49	47
Total expenses	832	831	1,638	1,660
Operating profit	677	651	1,324	1,163
Interest expense (income), net	37	42	74	83
Non-operating intercompany transactions	0	0	0	0
Income before taxes on income	640	609	1,250	1,080
(Benefit) provision for taxes on income	183	197	363	345
Equity in net income of subsidiaries	0	0	0	0
Net income	457	412	887	735
Less: net income attributable to noncontrolling interests	(36)	(29)	(67)	(58)
Net income attributable to S&P Global Inc.	421	383	820	677
Comprehensive income	493	365	961	708
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenue	(35)	(32)	(67)	(62)
Expenses:
Operating-related expenses	(35)	(32)	(67)	(62)
Selling and general expenses	0	0	0	0
Depreciation	0	0	0	0
Amortization of intangibles	0	0	0	0
Total expenses	(35)	(32)	(67)	(62)
Operating profit	0	0	0	0
Interest expense (income), net	0	0	0	0
Non-operating intercompany transactions	655	141	1,492	570
Income before taxes on income	(655)	(141)	(1,492)	(570)
(Benefit) provision for taxes on income	0	0	0	0
Equity in net income of subsidiaries	(1,064)	(689)	(2,288)	(1,552)
Net income	(1,719)	(830)	(3,780)	(2,122)
Less: net income attributable to noncontrolling interests	(36)	(29)	(67)	(58)
Net income attributable to S&P Global Inc.	(1,755)	(859)	(3,847)	(2,180)
Comprehensive income	(1,712)	(850)	(3,776)	(2,140)
S&P Global Inc.
Condensed Income Statements, Captions [Line Items]
Revenue	181	171	361	342
Expenses:
Operating-related expenses	39	26	71	49
Selling and general expenses	26	33	45	54
Depreciation	8	10	15	19
Amortization of intangibles	0	0	0	0
Total expenses	73	69	131	122
Operating profit	108	102	230	220
Interest expense (income), net	40	44	79	86
Non-operating intercompany transactions	93	95	175	169
Income before taxes on income	(25)	(37)	(24)	(35)
(Benefit) provision for taxes on income	(36)	(17)	(47)	(18)
Equity in net income of subsidiaries	1,064	617	2,288	1,408
Net income	1,075	597	2,311	1,391
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	1,075	597	2,311	1,391
Comprehensive income	1,085	545	2,323	1,347
Standard & Poor's Financial Services LLC
Condensed Income Statements, Captions [Line Items]
Revenue	447	413	885	754
Expenses:
Operating-related expenses	115	93	234	231
Selling and general expenses	83	62	172	97
Depreciation	3	2	5	5
Amortization of intangibles	0	0	0	0
Total expenses	201	157	411	333
Operating profit	246	256	474	421
Interest expense (income), net	0	0	0	0
Non-operating intercompany transactions	(22)	(37)	(41)	(42)
Income before taxes on income	268	293	515	463
(Benefit) provision for taxes on income	119	111	218	167
Equity in net income of subsidiaries	0	72	0	144
Net income	149	254	297	440
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	149	254	297	440
Comprehensive income	148	261	296	446
Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenue	916	930	1,783	1,789
Expenses:
Operating-related expenses	330	382	623	705
Selling and general expenses	229	222	472	499
Depreciation	9	10	19	16
Amortization of intangibles	25	23	49	47
Total expenses	593	637	1,163	1,267
Operating profit	323	293	620	522
Interest expense (income), net	(3)	(2)	(5)	(3)
Non-operating intercompany transactions	(726)	(199)	(1,626)	(697)
Income before taxes on income	1,052	494	2,251	1,222
(Benefit) provision for taxes on income	100	103	192	196
Equity in net income of subsidiaries	0	0	0	0
Net income	952	391	2,059	1,026
Less: net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to S&P Global Inc.	952	391	2,059	1,026
Comprehensive income	$ 972	$ 409	$ 2,118	$ 1,055