Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities:
Net income	$ 453	$ 534
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	20	21
Amortization of intangibles	32	24
Provision for losses on accounts receivable	7	8
Deferred income taxes	10	15
Stock-based compensation	12	13
Pension settlement charge, net of taxes	85	0
Other	8	1
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	(87)	7
Prepaid and other current assets	(34)	(21)
Accounts payable and accrued expenses	(161)	(289)
Unearned revenue	(3)	27
Accrued legal settlements	(1)	(29)
Other current liabilities	(59)	19
Net change in prepaid/accrued income taxes	75	74
Net change in other assets and liabilities	(64)	(44)
Cash provided by operating activities	293	360
Investing Activities:
Capital expenditures	(20)	(33)
Acquisitions, net of cash acquired	(1)	(57)
Changes in short-term investments	0	3
Cash used for investing activities	(21)	(87)
Financing Activities:
Dividends paid to shareholders	(141)	(127)
Distributions to noncontrolling interest holders, net	(18)	(50)
Repurchase of treasury shares	(644)	(1,100)
Exercise of stock options	23	10
Employee withholding tax on share-based payments	(49)	(49)
Intercompany financing activities	0	0
Cash used for financing activities	(829)	(1,316)
Effect of exchange rate changes on cash	35	20
Net change in cash, cash equivalents, and restricted cash	(522)	(1,023)
Cash, cash equivalents, and restricted cash at beginning of period	1,958	2,779
Cash, cash equivalents, and restricted cash at end of period	1,436	1,756
Eliminations
Operating Activities:
Net income	(529)	(2,528)
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
Deferred income taxes	0
Stock-based compensation	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	(529)	(2,528)
Investing Activities:
Capital expenditures	0	0
Acquisitions, net of cash acquired	0	0
Changes in short-term investments		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	529	2,528
Cash used for financing activities	529	2,528
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
Cash, cash equivalents, and restricted cash at end of period	0	0
S&P Global Inc. | Reportable Legal Entities
Operating Activities:
Net income	433	1,507
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	11	9
Amortization of intangibles	0	0
Provision for losses on accounts receivable	2	0
Deferred income taxes	3	(75)
Stock-based compensation	2	5
Pension settlement charge, net of taxes	85
Other	0	4
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	(80)	5
Prepaid and other current assets	(9)	(18)
Accounts payable and accrued expenses	(45)	(60)
Unearned revenue	9	(4)
Accrued legal settlements	0	0
Other current liabilities	(54)	(7)
Net change in prepaid/accrued income taxes	69	73
Net change in other assets and liabilities	(19)	(37)
Cash provided by operating activities	407	1,402
Investing Activities:
Capital expenditures	(8)	(23)
Acquisitions, net of cash acquired	0	0
Changes in short-term investments		0
Cash used for investing activities	(8)	(23)
Financing Activities:
Dividends paid to shareholders	(141)	(127)
Distributions to noncontrolling interest holders, net	0	0
Repurchase of treasury shares	(644)	(1,100)
Exercise of stock options	23	10
Employee withholding tax on share-based payments	(49)	(49)
Intercompany financing activities	(130)	(159)
Cash used for financing activities	(941)	(1,425)
Effect of exchange rate changes on cash	(6)	(5)
Net change in cash, cash equivalents, and restricted cash	(548)	(51)
Cash, cash equivalents, and restricted cash at beginning of period	694	632
Cash, cash equivalents, and restricted cash at end of period	146	581
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Operating Activities:
Net income	182	177
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	2	2
Amortization of intangibles	0	0
Provision for losses on accounts receivable	2	2
Deferred income taxes	0	0
Stock-based compensation	1	3
Pension settlement charge, net of taxes	0
Other	0	0
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	(101)	(27)
Prepaid and other current assets	(2)	1
Accounts payable and accrued expenses	(18)	(79)
Unearned revenue	23	28
Accrued legal settlements	(1)	0
Other current liabilities	(1)	(2)
Net change in prepaid/accrued income taxes	0	1
Net change in other assets and liabilities	(5)	0
Cash provided by operating activities	82	106
Investing Activities:
Capital expenditures	(4)	(6)
Acquisitions, net of cash acquired	0	0
Changes in short-term investments		0
Cash used for investing activities	(4)	(6)
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	(78)	(100)
Cash used for financing activities	(78)	(100)
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
Cash, cash equivalents, and restricted cash at end of period	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Activities:
Net income	367	1,378
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	7	10
Amortization of intangibles	32	24
Provision for losses on accounts receivable	3	6
Deferred income taxes	7	90
Stock-based compensation	9	5
Pension settlement charge, net of taxes	0
Other	8	(3)
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	94	29
Prepaid and other current assets	(23)	(4)
Accounts payable and accrued expenses	(98)	(150)
Unearned revenue	(35)	3
Accrued legal settlements	0	(29)
Other current liabilities	(4)	28
Net change in prepaid/accrued income taxes	6	0
Net change in other assets and liabilities	(40)	(7)
Cash provided by operating activities	333	1,380
Investing Activities:
Capital expenditures	(8)	(4)
Acquisitions, net of cash acquired	(1)	(57)
Changes in short-term investments		3
Cash used for investing activities	(9)	(58)
Financing Activities:
Dividends paid to shareholders	0	0
Distributions to noncontrolling interest holders, net	(18)	(50)
Repurchase of treasury shares	0	0
Exercise of stock options	0
Employee withholding tax on share-based payments	0	0
Intercompany financing activities	(321)	(2,269)
Cash used for financing activities	(339)	(2,319)
Effect of exchange rate changes on cash	41	25
Net change in cash, cash equivalents, and restricted cash	26	(972)
Cash, cash equivalents, and restricted cash at beginning of period	1,264	2,147
Cash, cash equivalents, and restricted cash at end of period	$ 1,290	$ 1,175