Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating Activities:
Net income	$ 452	$ 923	$ 1,339	$ 1,659
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			61	63
Amortization of intangibles			73	71
Provision for losses on accounts receivable			17	10
Stock-based compensation			65	54
Gain on disposition	0	(722)	0	(722)
Other			42	48
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			(64)	(26)
Prepaid and other current assets			3	5
Accounts payable and accrued expenses			(50)	(81)
Unearned revenue			(107)	(6)
Accrued legal settlements			(4)	(134)
Other current liabilities			(94)	(10)
Net change in prepaid/accrued income taxes			(42)	383
Net change in other assets and liabilities			(36)	(57)
Cash provided by operating activities			1,203	1,257
Investing Activities:
Capital expenditures			(77)	(67)
Acquisitions, net of cash acquired			(80)	(145)
Proceeds from dispositions			2	1,071
Changes in short-term investments			0	(1)
Cash (used for) provided by investing activities			(155)	858
Financing Activities:
Payments on short-term debt, net			0	(143)
Proceeds from issuance of senior notes, net			0	493
Dividends paid to shareholders			(316)	(286)
Distributions to noncontrolling interest holders			(69)	(59)
Contingent consideration payments			0	(15)
Repurchase of treasury shares			(846)	(1,123)
Exercise of stock options			69	84
Employee withholding tax on share-based payments			(49)	(55)
Intercompany financing activities			0	0
Cash used for financing activities			(1,211)	(1,104)
Effect of exchange rate changes on cash from continuing operations			83	(93)
Net change in cash and cash equivalents			(80)	918
Cash and cash equivalents at beginning of period			2,392	1,481
Cash and cash equivalents at end of period	2,312	2,399	2,312	2,399
Eliminations
Operating Activities:
Net income	(422)	(581)	(4,199)	(2,637)
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			0	0
Amortization of intangibles			0	0
Provision for losses on accounts receivable			0	0
Stock-based compensation			0	0
Gain on disposition		0		0
Other			0	0
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			0	0
Prepaid and other current assets			0	0
Accounts payable and accrued expenses			0	0
Unearned revenue			0	0
Accrued legal settlements			0	0
Other current liabilities			0	0
Net change in prepaid/accrued income taxes			0	0
Net change in other assets and liabilities			0	0
Cash provided by operating activities			(4,199)	(2,637)
Investing Activities:
Capital expenditures			0	0
Acquisitions, net of cash acquired			0	0
Proceeds from dispositions			0	0
Changes in short-term investments				0
Cash (used for) provided by investing activities			0	0
Financing Activities:
Payments on short-term debt, net				0
Proceeds from issuance of senior notes, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			0	0
Contingent consideration payments				0
Repurchase of treasury shares			0	0
Exercise of stock options			0	0
Employee withholding tax on share-based payments			0	0
Intercompany financing activities			4,199	2,637
Cash used for financing activities			4,199	2,637
Effect of exchange rate changes on cash from continuing operations			0	0
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
S&P Global Inc.
Operating Activities:
Net income	427	1,016	2,735	2,341
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			24	28
Amortization of intangibles			0	0
Provision for losses on accounts receivable			1	2
Stock-based compensation			23	17
Gain on disposition		(705)		(705)
Other			27	(66)
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			(2)	5
Prepaid and other current assets			(8)	(7)
Accounts payable and accrued expenses			(19)	(24)
Unearned revenue			14	20
Accrued legal settlements			0	0
Other current liabilities			(42)	(15)
Net change in prepaid/accrued income taxes			(27)	328
Net change in other assets and liabilities			(42)	(35)
Cash provided by operating activities			2,684	1,889
Investing Activities:
Capital expenditures			(34)	(34)
Acquisitions, net of cash acquired			0	(140)
Proceeds from dispositions			0	1,047
Changes in short-term investments				0
Cash (used for) provided by investing activities			(34)	873
Financing Activities:
Payments on short-term debt, net				(143)
Proceeds from issuance of senior notes, net				493
Dividends paid to shareholders			(316)	(286)
Distributions to noncontrolling interest holders			0	0
Contingent consideration payments				(5)
Repurchase of treasury shares			(846)	(1,123)
Exercise of stock options			63	83
Employee withholding tax on share-based payments			(49)	(55)
Intercompany financing activities			(1,960)	(1,155)
Cash used for financing activities			(3,108)	(2,191)
Effect of exchange rate changes on cash from continuing operations			(10)	0
Net change in cash and cash equivalents			(468)	571
Cash and cash equivalents at beginning of period			711	167
Cash and cash equivalents at end of period	243	738	243	738
Standard & Poor's Financial Services LLC
Operating Activities:
Net income	113	223	409	663
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			9	7
Amortization of intangibles			0	0
Provision for losses on accounts receivable			2	0
Stock-based compensation			15	12
Gain on disposition		0		0
Other			15	3
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			(73)	159
Prepaid and other current assets			2	13
Accounts payable and accrued expenses			56	(147)
Unearned revenue			17	(385)
Accrued legal settlements			(1)	(108)
Other current liabilities			(11)	(25)
Net change in prepaid/accrued income taxes			(18)	0
Net change in other assets and liabilities			(5)	29
Cash provided by operating activities			417	221
Investing Activities:
Capital expenditures			(17)	(11)
Acquisitions, net of cash acquired			0	0
Proceeds from dispositions			0	0
Changes in short-term investments				0
Cash (used for) provided by investing activities			(17)	(11)
Financing Activities:
Payments on short-term debt, net				0
Proceeds from issuance of senior notes, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			0	0
Contingent consideration payments				0
Repurchase of treasury shares			0	0
Exercise of stock options			0	0
Employee withholding tax on share-based payments			0	0
Intercompany financing activities			(400)	(210)
Cash used for financing activities			(400)	(210)
Effect of exchange rate changes on cash from continuing operations			0	0
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Non-Guarantor Subsidiaries
Operating Activities:
Net income	334	265	2,394	1,292
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			28	28
Amortization of intangibles			73	71
Provision for losses on accounts receivable			14	8
Stock-based compensation			27	25
Gain on disposition		(17)		(17)
Other			0	111
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			11	(190)
Prepaid and other current assets			9	(1)
Accounts payable and accrued expenses			(87)	90
Unearned revenue			(138)	359
Accrued legal settlements			(3)	(26)
Other current liabilities			(41)	30
Net change in prepaid/accrued income taxes			3	55
Net change in other assets and liabilities			11	(51)
Cash provided by operating activities			2,301	1,784
Investing Activities:
Capital expenditures			(26)	(22)
Acquisitions, net of cash acquired			(80)	(5)
Proceeds from dispositions			2	24
Changes in short-term investments				(1)
Cash (used for) provided by investing activities			(104)	(4)
Financing Activities:
Payments on short-term debt, net				0
Proceeds from issuance of senior notes, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			(69)	(59)
Contingent consideration payments				(10)
Repurchase of treasury shares			0	0
Exercise of stock options			6	1
Employee withholding tax on share-based payments			0	0
Intercompany financing activities			(1,839)	(1,272)
Cash used for financing activities			(1,902)	(1,340)
Effect of exchange rate changes on cash from continuing operations			93	(93)
Net change in cash and cash equivalents			388	347
Cash and cash equivalents at beginning of period			1,681	1,314
Cash and cash equivalents at end of period	$ 2,069	$ 1,661	$ 2,069	$ 1,661