Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net income		$ 662	$ 535	$ 1,717	$ 1,570
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation		20	20	61	60
Amortization of intangibles		29	33	92	91
Provision for losses on accounts receivable				17	16
Deferred income taxes				15	21
Stock-based compensation				53	73
Gain on dispositions		(49)	0	(49)	0
Pension settlement charge, net of taxes				85	0
Other				49	20
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				(50)	62
Prepaid and other current assets				(59)	1
Accounts payable and accrued expenses				(54)	(167)
Unearned revenue				(27)	(72)
Accrued legal settlements				(1)	(180)
Other current liabilities				(81)	(18)
Net change in prepaid/accrued income taxes				58	62
Net change in other assets and liabilities				(54)	(138)
Cash provided by operating activities				1,772	1,401
Investing Activities:
Capital expenditures				(77)	(88)
Acquisitions, net of cash acquired				(25)	(263)
Proceeds from dispositions				85	0
Changes in short-term investments				(3)	5
Cash used for investing activities				(20)	(346)
Financing Activities:
Proceeds from issuance of senior notes, net				0	489
Payments on senior notes				0	(403)
Dividends paid to shareholders				(421)	(379)
Distributions to noncontrolling interest holders, net				(100)	(116)
Purchase of CRISIL shares				0	(25)
Repurchase of treasury shares	$ (6)			(1,144)	(1,108)
Exercise of stock options				38	24
Employee withholding tax on share-based payments and other				(57)	(61)
Intercompany financing activities				0	0
Cash used for financing activities				(1,684)	(1,579)
Effect of exchange rate changes on cash				(7)	(52)
Net change in cash, cash equivalents, and restricted cash				61	(576)
Cash, cash equivalents, and restricted cash at beginning of period	2,203			1,958	2,779
Cash, cash equivalents, and restricted cash at end of period		2,019	2,203	2,019	2,203
Eliminations
Operating Activities:
Net income		(635)	(444)	(4,063)	(4,119)
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
Stock-based compensation				0	0
Gain on dispositions		0	0	0	0
Pension settlement charge, net of taxes				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	0
Other current liabilities				0	0
Net change in prepaid/accrued income taxes				0	0
Net change in other assets and liabilities					0
Cash provided by operating activities				(4,063)	(4,119)
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:
Proceeds from issuance of senior notes, net					0
Payments on senior notes					0
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				0	0
Purchase of CRISIL shares					0
Repurchase of treasury shares				0	0
Exercise of stock options				0	0
Employee withholding tax on share-based payments and other				0	0
Intercompany financing activities				4,063	4,119
Cash used for financing activities				4,063	4,119
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.
Investing Activities:
Changes in short-term investments				0
S&P Global Inc. | Reportable Legal Entities
Operating Activities:
Net income		629	500	2,777	2,801
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation		11	11	33	31
Amortization of intangibles		0	0	0	0
Provision for losses on accounts receivable				5	1
Deferred income taxes				4	(3)
Stock-based compensation				17	21
Gain on dispositions		(49)	0	(49)	0
Pension settlement charge, net of taxes				85
Other				12	36
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				(90)	10
Prepaid and other current assets				(20)	(11)
Accounts payable and accrued expenses				(17)	(31)
Unearned revenue				35	(20)
Accrued legal settlements				0
Other current liabilities				(62)	(15)
Net change in prepaid/accrued income taxes				49	51
Net change in other assets and liabilities				(56)	(123)
Cash provided by operating activities				2,723	2,748
Investing Activities:
Capital expenditures				(32)	(63)
Acquisitions, net of cash acquired				0	0
Proceeds from dispositions				85
Changes in short-term investments					0
Cash used for investing activities				53	(63)
Financing Activities:
Proceeds from issuance of senior notes, net					489
Payments on senior notes					(403)
Dividends paid to shareholders				(421)	(379)
Distributions to noncontrolling interest holders, net				0	0
Purchase of CRISIL shares					0
Repurchase of treasury shares				(1,144)	(1,108)
Exercise of stock options				36	18
Employee withholding tax on share-based payments and other				(55)	(61)
Intercompany financing activities				(1,377)	(968)
Cash used for financing activities				(2,961)	(2,412)
Effect of exchange rate changes on cash				0	(14)
Net change in cash, cash equivalents, and restricted cash				(185)	259
Cash, cash equivalents, and restricted cash at beginning of period	891			694	632
Cash, cash equivalents, and restricted cash at end of period		509	891	509	891
Standard & Poor's Financial Services LLC
Investing Activities:
Changes in short-term investments				0
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Operating Activities:
Net income		253	147	658	569
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation		3	2	9	6
Amortization of intangibles		0	0	0	0
Provision for losses on accounts receivable				1	1
Deferred income taxes				1	0
Stock-based compensation				9	12
Gain on dispositions		0	0	0	0
Pension settlement charge, net of taxes				0
Other				6	0
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				(86)	(15)
Prepaid and other current assets				2	1
Accounts payable and accrued expenses				(1)	(58)
Unearned revenue				21	23
Accrued legal settlements				(1)	0
Other current liabilities				(5)	(8)
Net change in prepaid/accrued income taxes				1	2
Net change in other assets and liabilities				(3)	23
Cash provided by operating activities				612	556
Investing Activities:
Capital expenditures				(3)	(14)
Acquisitions, net of cash acquired				0	0
Proceeds from dispositions				0
Changes in short-term investments					0
Cash used for investing activities				(3)	(14)
Financing Activities:
Proceeds from issuance of senior notes, net					0
Payments on senior notes					0
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				0	0
Purchase of CRISIL shares					0
Repurchase of treasury shares				0	0
Exercise of stock options				0	0
Employee withholding tax on share-based payments and other				0	0
Intercompany financing activities				(609)	(542)
Cash used for financing activities				(609)	(542)
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
Investing Activities:
Changes in short-term investments				(3)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Activities:
Net income		415	332	2,345	2,319
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation		6	7	19	23
Amortization of intangibles		29	33	92	91
Provision for losses on accounts receivable				11	14
Deferred income taxes				10	24
Stock-based compensation				27	40
Gain on dispositions		0	0	0	0
Pension settlement charge, net of taxes				0
Other				31	(16)
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable				126	67
Prepaid and other current assets				(41)	11
Accounts payable and accrued expenses				(36)	(78)
Unearned revenue				(83)	(75)
Accrued legal settlements				0	(180)
Other current liabilities				(14)	5
Net change in prepaid/accrued income taxes				8	9
Net change in other assets and liabilities				5	(38)
Cash provided by operating activities				2,500	2,216
Investing Activities:
Capital expenditures				(42)	(11)
Acquisitions, net of cash acquired				(25)	(263)
Proceeds from dispositions
Changes in short-term investments					5
Cash used for investing activities				(70)	(269)
Financing Activities:
Proceeds from issuance of senior notes, net					0
Payments on senior notes					0
Dividends paid to shareholders				0	0
Distributions to noncontrolling interest holders, net				(100)	(116)
Purchase of CRISIL shares					(25)
Repurchase of treasury shares				0	0
Exercise of stock options				2	6
Employee withholding tax on share-based payments and other				(2)	0
Intercompany financing activities				(2,077)	(2,609)
Cash used for financing activities				(2,177)	(2,744)
Effect of exchange rate changes on cash				(7)	(38)
Net change in cash, cash equivalents, and restricted cash				246	(835)
Cash, cash equivalents, and restricted cash at beginning of period	$ 1,312			1,264	2,147
Cash, cash equivalents, and restricted cash at end of period		$ 1,510	$ 1,312	$ 1,510	$ 1,312