Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 457	$ 412	$ 887	$ 735
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			39	40
Amortization of intangibles			49	47
Provision for losses on accounts receivable			13	8
Stock-based compensation			41	34
Other			26	43
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			(49)	(39)
Prepaid and other current assets			(13)	(14)
Accounts payable and accrued expenses			(139)	(171)
Unearned revenue			(17)	38
Accrued legal settlements			(4)	(108)
Other current liabilities			(85)	(21)
Net change in prepaid/accrued income taxes			(45)	92
Net change in other assets and liabilities			(29)	(44)
Cash provided by operating activities			674	640
Investing Activities:
Capital expenditures			(56)	(36)
Acquisitions, net of cash acquired			(70)	(52)
Proceeds from dispositions			2	0
Cash used for investing activities			(124)	(88)
Financing Activities:
Additions to short-term debt, net			0	166
Dividends paid to shareholders			(212)	(191)
Distributions to noncontrolling interest holders			(54)	(57)
Repurchase of treasury shares			(346)	(373)
Exercise of stock options			38	65
Employee withholding tax on share-based payments			(44)	(50)
Intercompany financing activities			0	0
Cash used for financing activities			(618)	(440)
Effect of exchange rate changes on cash from continuing operations			60	(26)
Net change in cash and cash equivalents			(8)	86
Cash and cash equivalents at beginning of period			2,392	1,481
Cash and cash equivalents at end of period	2,384	1,567	2,384	1,567
Eliminations
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	(1,719)	(830)	(3,780)	(2,122)
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
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			(3,780)	(2,122)
Investing Activities:
Capital expenditures			0	0
Acquisitions, net of cash acquired			0	0
Proceeds from dispositions			0
Cash used for investing activities			0	0
Financing Activities:
Additions to short-term debt, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			0	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			3,780	2,122
Cash used for financing activities			3,780	2,122
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.
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	1,075	597	2,311	1,391
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			15	19
Amortization of intangibles			0	0
Provision for losses on accounts receivable			0	1
Stock-based compensation			14	10
Other			17	(1)
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			14	(7)
Prepaid and other current assets			(18)	(21)
Accounts payable and accrued expenses			(40)	(26)
Unearned revenue			1	18
Accrued legal settlements			0	0
Other current liabilities			(33)	(23)
Net change in prepaid/accrued income taxes			(55)	83
Net change in other assets and liabilities			(17)	(31)
Cash provided by operating activities			2,209	1,413
Investing Activities:
Capital expenditures			(19)	(16)
Acquisitions, net of cash acquired			0	(40)
Proceeds from dispositions			0
Cash used for investing activities			(19)	(56)
Financing Activities:
Additions to short-term debt, net				166
Dividends paid to shareholders			(212)	(191)
Distributions to noncontrolling interest holders			0	0
Repurchase of treasury shares			(346)	(373)
Exercise of stock options			38	64
Employee withholding tax on share-based payments			(44)	(50)
Intercompany financing activities			(1,842)	(1,038)
Cash used for financing activities			(2,406)	(1,422)
Effect of exchange rate changes on cash from continuing operations			14	(40)
Net change in cash and cash equivalents			(202)	(105)
Cash and cash equivalents at beginning of period			711	167
Cash and cash equivalents at end of period	509	62	509	62
Standard & Poor's Financial Services LLC
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	149	254	297	440
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			5	5
Amortization of intangibles			0	0
Provision for losses on accounts receivable			4	1
Stock-based compensation			10	7
Other			0	8
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			(63)	148
Prepaid and other current assets			3	13
Accounts payable and accrued expenses			34	(98)
Unearned revenue			28	(375)
Accrued legal settlements			(1)	(108)
Other current liabilities			(4)	(25)
Net change in prepaid/accrued income taxes			0	0
Net change in other assets and liabilities			1	27
Cash provided by operating activities			314	43
Investing Activities:
Capital expenditures			(10)	(7)
Acquisitions, net of cash acquired			0	0
Proceeds from dispositions			0
Cash used for investing activities			(10)	(7)
Financing Activities:
Additions to short-term debt, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			0	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			(304)	(36)
Cash used for financing activities			(304)	(36)
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
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	952	391	2,059	1,026
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation			19	16
Amortization of intangibles			49	47
Provision for losses on accounts receivable			9	6
Stock-based compensation			17	17
Other			9	36
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable			0	(180)
Prepaid and other current assets			2	(6)
Accounts payable and accrued expenses			(133)	(47)
Unearned revenue			(46)	395
Accrued legal settlements			(3)	0
Other current liabilities			(48)	27
Net change in prepaid/accrued income taxes			10	9
Net change in other assets and liabilities			(13)	(40)
Cash provided by operating activities			1,931	1,306
Investing Activities:
Capital expenditures			(27)	(13)
Acquisitions, net of cash acquired			(70)	(12)
Proceeds from dispositions			2
Cash used for investing activities			(95)	(25)
Financing Activities:
Additions to short-term debt, net				0
Dividends paid to shareholders			0	0
Distributions to noncontrolling interest holders			(54)	(57)
Repurchase of treasury shares			0	0
Exercise of stock options			0	1
Employee withholding tax on share-based payments			0	0
Intercompany financing activities			(1,634)	(1,048)
Cash used for financing activities			(1,688)	(1,104)
Effect of exchange rate changes on cash from continuing operations			46	14
Net change in cash and cash equivalents			194	191
Cash and cash equivalents at beginning of period			1,681	1,314
Cash and cash equivalents at end of period	$ 1,875	$ 1,505	$ 1,875	$ 1,505