Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating Activities:
Net income	$ 842		$ 602	$ 1,531	$ 1,055
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	19		21	39	41
Amortization of intangibles	32		31	61	63
Provision for losses on accounts receivable				14	12
Deferred income taxes				3	30
Stock-based compensation				22	33
Gain on disposition	(1)		0	(8)	0
Pension settlement charges, net of taxes				2	85
Other				27	38
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				30	(95)
Prepaid and other current assets				(48)	(42)
Accounts payable and accrued expenses				(192)	(74)
Unearned revenue				(56)	0
Accrued legal settlements				0	(1)
Other current liabilities				(16)	(83)
Net change in prepaid/accrued income taxes				247	15
Net change in other assets and liabilities				(39)	(67)
Cash provided by operating activities				1,617	1,010
Investing Activities:
Capital expenditures				(18)	(46)
Acquisitions, net of cash acquired				(185)	(4)
Proceeds from dispositions				2	0
Changes in short-term investments				15	(3)
Cash used for investing activities				(186)	(53)
Financing Activities:
Dividends paid to shareholders				(323)	(281)
Distributions to noncontrolling interest holders, net				(92)	(59)
Repurchase of treasury shares		$ (1,153)		(1,153)	(644)
Exercise of stock options				12	31
Employee withholding tax on share-based payments				(54)	(55)
Intercompany financing activities				0	0
Cash used for financing activities				(1,610)	(1,008)
Effect of exchange rate changes on cash				(23)	13
Net change in cash, cash equivalents, and restricted cash				(202)	(38)
Cash, cash equivalents, and restricted cash at beginning of period		2,886		2,886	1,958
Cash, cash equivalents, and restricted cash at end of period	2,684		1,920	2,684	1,920
Eliminations
Operating Activities:
Net income	(2,092)		(2,900)	(3,733)	(3,429)
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	0		0	0	0
Amortization of intangibles	0		0	0	0
Provision for losses on accounts receivable				0	0
Deferred income taxes				0	0
Stock-based compensation				0	0
Gain on disposition	0			0
Pension settlement charges, net of taxes				0	0
Other				0	0
Changes in operating assets and liabilities, net of effect of acquisitions:
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
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				(3,733)	(3,429)
Investing Activities:
Capital expenditures				0	0
Acquisitions, net of cash acquired				0	0
Proceeds from dispositions				0
Changes in short-term investments				0	0
Cash used for investing activities				0	0
Financing Activities:
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				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				3,733	3,429
Cash used for financing activities				3,733	3,429
Effect of exchange rate changes on cash				0	0
Net change in cash, cash equivalents, and restricted cash				0	0
Cash, cash equivalents, and restricted cash at beginning of period		0		0	0
Cash, cash equivalents, and restricted cash at end of period	0		0	0	0
S&P Global Inc. | Reportable Legal Entities
Operating Activities:
Net income	1,473		1,715	2,586	2,147
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	10		10	20	22
Amortization of intangibles	0		0	0	0
Provision for losses on accounts receivable				4	3
Deferred income taxes				6	22
Stock-based compensation				8	9
Gain on disposition	0			0
Pension settlement charges, net of taxes				0	85
Other				19	8
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				1	(109)
Prepaid and other current assets				(62)	(1)
Accounts payable and accrued expenses				(48)	1
Unearned revenue				21	28
Accrued legal settlements					0
Other current liabilities				(12)	(57)
Net change in prepaid/accrued income taxes				293	15
Net change in other assets and liabilities				(2)	(26)
Cash provided by operating activities				2,834	2,147
Investing Activities:
Capital expenditures				(8)	(25)
Acquisitions, net of cash acquired				0	0
Proceeds from dispositions				0
Changes in short-term investments				0	0
Cash used for investing activities				(8)	(25)
Financing Activities:
Dividends paid to shareholders				(323)	(281)
Distributions to noncontrolling interest holders, net				0	0
Repurchase of treasury shares				(1,153)	(644)
Exercise of stock options				9	29
Employee withholding tax on share-based payments				(54)	(53)
Intercompany financing activities				(827)	(1,311)
Cash used for financing activities				(2,348)	(2,260)
Effect of exchange rate changes on cash				(6)	0
Net change in cash, cash equivalents, and restricted cash				472	(138)
Cash, cash equivalents, and restricted cash at beginning of period		1,130		1,130	694
Cash, cash equivalents, and restricted cash at end of period	1,602		556	1,602	556
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Operating Activities:
Net income	358		223	658	406
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	3		4	5	6
Amortization of intangibles	0		0	0	0
Provision for losses on accounts receivable				4	3
Deferred income taxes				(1)	1
Stock-based compensation				3	4
Gain on disposition	0			0
Pension settlement charges, net of taxes				0	0
Other				0	7
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				(106)	(88)
Prepaid and other current assets				41	2
Accounts payable and accrued expenses				(38)	(13)
Unearned revenue				8	27
Accrued legal settlements					(1)
Other current liabilities				6	(3)
Net change in prepaid/accrued income taxes				(41)	0
Net change in other assets and liabilities				(18)	(4)
Cash provided by operating activities				521	347
Investing Activities:
Capital expenditures				(3)	(3)
Acquisitions, net of cash acquired				0	0
Proceeds from dispositions				0
Changes in short-term investments				0	0
Cash used for investing activities				(3)	(3)
Financing Activities:
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				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				(518)	(344)
Cash used for financing activities				(518)	(344)
Effect of exchange rate changes on cash				0	0
Net change in cash, cash equivalents, and restricted cash				0	0
Cash, cash equivalents, and restricted cash at beginning of period		0		0	0
Cash, cash equivalents, and restricted cash at end of period	0		0	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Activities:
Net income	1,103		1,564	2,020	1,931
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	6		7	14	13
Amortization of intangibles	32		31	61	63
Provision for losses on accounts receivable				6	6
Deferred income taxes				(2)	7
Stock-based compensation				11	20
Gain on disposition	(1)			(8)
Pension settlement charges, net of taxes				2	0
Other				8	23
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				135	102
Prepaid and other current assets				(27)	(43)
Accounts payable and accrued expenses				(106)	(62)
Unearned revenue				(85)	(55)
Accrued legal settlements					0
Other current liabilities				(10)	(23)
Net change in prepaid/accrued income taxes				(5)	0
Net change in other assets and liabilities				(19)	(37)
Cash provided by operating activities				1,995	1,945
Investing Activities:
Capital expenditures				(7)	(18)
Acquisitions, net of cash acquired				(185)	(4)
Proceeds from dispositions				2
Changes in short-term investments				15	(3)
Cash used for investing activities				(175)	(25)
Financing Activities:
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				(92)	(59)
Repurchase of treasury shares				0	0
Exercise of stock options				3	2
Employee withholding tax on share-based payments				0	(2)
Intercompany financing activities				(2,388)	(1,774)
Cash used for financing activities				(2,477)	(1,833)
Effect of exchange rate changes on cash				(17)	13
Net change in cash, cash equivalents, and restricted cash				(674)	100
Cash, cash equivalents, and restricted cash at beginning of period		$ 1,756		1,756	1,264
Cash, cash equivalents, and restricted cash at end of period	$ 1,082		$ 1,364	$ 1,082	$ 1,364