Condensed Consolidating Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Revenue	$ 1,399	$ 1,439	$ 1,482	$ 1,341	$ 1,374	$ 1,324	$ 1,342	$ 1,273	$ 5,661	$ 5,313	$ 5,051
Expenses:
Operating-related expenses									1,769	1,700	1,651
Selling and general expenses									1,443	1,550	3,144
Depreciation									85	90	86
Amortization of intangibles									96	67	48
Total expenses									3,393	3,407	4,929
Gain on dispositions									(1,101)	(11)	9
Operating profit	857	1,348	651	512	424	410	582	501	3,369	1,917	113
Interest expense (income), net									181	102	59
Non-operating intercompany transactions									0	0	0
Income from continuing operations before taxes on income									3,188	1,815	54
Provision for taxes on income									960	547	245
Equity in net income of subsidiaries									0	0	0
Income (loss) from continuing operations									2,228	1,268	(191)
Discontinued operations, net of tax:
Income from discontinued operations									0	0	18
Gain on sale of discontinued operations									0	0	160
Discontinued operations, net									0	0	178
Net income (loss)	569	923	412	323	276	281	381	329	2,228	1,268	(13)
Less: net income from continuing operations attributable to noncontrolling interests									(122)	(112)	(102)
Net income (loss) attributable to S&P Global Inc.	$ 537	$ 892	$ 383	$ 294	$ 248	$ 252	$ 353	$ 303	2,106	1,156	(115)
Comprehensive income (loss)									2,055	1,182	(331)
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenue									(126)	(115)	(115)
Expenses:
Operating-related expenses									(126)	(115)	(115)
Selling and general expenses									0	0	0
Depreciation									0	0	0
Amortization of intangibles									0	0	0
Total expenses									(126)	(115)	(115)
Gain on dispositions									0	0	0
Operating profit									0	0	0
Interest expense (income), net									0	0	0
Non-operating intercompany transactions									668	0	0
Income from continuing operations before taxes on income									(668)	0	0
Provision for taxes on income									0	0	0
Equity in net income of subsidiaries									(2,706)	(1,745)	195
Income (loss) from continuing operations											195
Discontinued operations, net of tax:
Income from discontinued operations											0
Gain on sale of discontinued operations											0
Discontinued operations, net											0
Net income (loss)									(3,374)	(1,745)	195
Less: net income from continuing operations attributable to noncontrolling interests									(122)	(112)	(102)
Net income (loss) attributable to S&P Global Inc.									(3,496)	(1,857)	93
Comprehensive income (loss)									(3,374)	(1,741)	195
S&P Global Inc. | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue									667	624	598
Expenses:
Operating-related expenses									109	119	117
Selling and general expenses									113	202	257
Depreciation									38	40	41
Amortization of intangibles									0	0	4
Total expenses									260	361	419
Gain on dispositions									(1,072)	0	3
Operating profit									1,479	263	176
Interest expense (income), net									191	112	66
Non-operating intercompany transactions									356	282	193
Income from continuing operations before taxes on income									932	(131)	(83)
Provision for taxes on income									275	(107)	(22)
Equity in net income of subsidiaries									2,412	1,473	(443)
Income (loss) from continuing operations											(504)
Discontinued operations, net of tax:
Income from discontinued operations											18
Gain on sale of discontinued operations											160
Discontinued operations, net											178
Net income (loss)									3,069	1,449	(326)
Less: net income from continuing operations attributable to noncontrolling interests									0	0	0
Net income (loss) attributable to S&P Global Inc.									3,069	1,449	(326)
Comprehensive income (loss)									3,099	1,446	(495)
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue									1,513	2,141	2,043
Expenses:
Operating-related expenses									451	737	764
Selling and general expenses									243	254	1,975
Depreciation									9	18	17
Amortization of intangibles									0	0	0
Total expenses									703	1,009	2,756
Gain on dispositions									0	0	0
Operating profit									810	1,132	(713)
Interest expense (income), net									0	0	0
Non-operating intercompany transactions									(83)	222	38
Income from continuing operations before taxes on income									893	910	(751)
Provision for taxes on income									420	358	16
Equity in net income of subsidiaries									294	272	248
Income (loss) from continuing operations											(519)
Discontinued operations, net of tax:
Income from discontinued operations											0
Gain on sale of discontinued operations											0
Discontinued operations, net											0
Net income (loss)									767	824	(519)
Less: net income from continuing operations attributable to noncontrolling interests									0	0	0
Net income (loss) attributable to S&P Global Inc.									767	824	(519)
Comprehensive income (loss)									767	822	(544)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Revenue									3,607	2,663	2,525
Expenses:
Operating-related expenses									1,335	959	885
Selling and general expenses									1,087	1,094	912
Depreciation									38	32	28
Amortization of intangibles									96	67	44
Total expenses									2,556	2,152	1,869
Gain on dispositions									(29)	(11)	6
Operating profit									1,080	522	650
Interest expense (income), net									(10)	(10)	(7)
Non-operating intercompany transactions									(941)	(504)	(231)
Income from continuing operations before taxes on income									2,031	1,036	888
Provision for taxes on income									265	296	251
Equity in net income of subsidiaries									0	0	0
Income (loss) from continuing operations											637
Discontinued operations, net of tax:
Income from discontinued operations											0
Gain on sale of discontinued operations											0
Discontinued operations, net											0
Net income (loss)									1,766	740	637
Less: net income from continuing operations attributable to noncontrolling interests									0	0	0
Net income (loss) attributable to S&P Global Inc.									1,766	740	637
Comprehensive income (loss)									$ 1,563	$ 655	$ 513