Condensed Consolidating Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities:
Net income	$ 585	$ 662	$ 602	$ 453	$ 551	$ 535	$ 501	$ 534	$ 2,303	$ 2,121	$ 1,638
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation									82	84	82
Amortization of intangibles									122	122	98
Provision for losses on accounts receivable									18	21	16
Deferred income taxes									46	81	0
Stock-based compensation									78	94	99
Gain on dispositions									(49)	0	0
Accrued legal settlements									0	1	55
Pension settlement charge, net of taxes									85	0	0
Other									93	52	96
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable									(135)	(164)	(196)
Prepaid and other current assets									(81)	(1)	10
Accounts payable and accrued expenses									73	(106)	75
Unearned revenue									256	70	85
Accrued legal settlements									(1)	(108)	(4)
Other current liabilities									(56)	(67)	(85)
Net change in prepaid/accrued income taxes									(41)	(7)	32
Net change in other assets and liabilities									(17)	(129)	15
Cash provided by operating activities									2,776	2,064	2,016
Investing Activities:
Capital expenditures									(115)	(113)	(123)
Acquisitions, net of cash acquired									(91)	(401)	(83)
Proceeds from dispositions									85	6	2
Changes in short-term investments									(10)	(5)	(5)
Cash used for investing activities									(131)	(513)	(209)
Financing Activities:
Proceeds from issuance of senior notes, net									1,086	489	0
Payments on senior notes									(868)	(403)	0
Dividends paid to shareholders									(560)	(503)	(421)
Distributions to noncontrolling interest holders, net									(143)	(154)	(111)
Repurchase of treasury shares									(1,240)	(1,660)	(1,001)
Exercise of stock options									40	34	75
Contingent consideration payment										(25)
Employee withholding tax on share-based payments and other									(66)	(66)	(49)
Intercompany financing activities									0	0	0
Cash used for financing activities									(1,751)	(2,288)	(1,507)
Effect of exchange rate changes on cash									34	(84)	87
Net change in cash, cash equivalents, and restricted cash									928	(821)	387
Cash, cash equivalents, and restricted cash at beginning of year				1,958				2,779	1,958	2,779	2,392
Cash, cash equivalents, and restricted cash at end of year	2,886				1,958				2,886	1,958	2,779
Eliminations
Operating Activities:
Net income									(4,605)	(5,159)	(5,983)
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation									0	0	0
Amortization of intangibles									0	0	0
Provision for losses on accounts receivable									0	0	0
Deferred income taxes									0	0	0
Stock-based compensation									0	0	0
Gain on dispositions									0
Accrued legal settlements										0	0
Pension settlement charge, net of taxes									0
Other									0	0	0
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable									0	0	0
Prepaid and other current assets									0	0	0
Accounts payable and accrued expenses									0	0	0
Unearned revenue									0	0	0
Accrued legal settlements									0	0	0
Other current liabilities									0	0	0
Net change in prepaid/accrued income taxes									0	0	0
Net change in other assets and liabilities									0	0	0
Cash provided by operating activities									(4,605)	(5,159)	(5,983)
Investing Activities:
Capital expenditures									0	0	0
Acquisitions, net of cash acquired									0	0	0
Proceeds from dispositions									0	0	0
Changes in short-term investments									0	0	0
Cash used for investing activities									0	0	0
Financing Activities:
Proceeds from issuance of senior notes, net									0	0
Payments on senior notes									0	0
Dividends paid to shareholders									0	0	0
Distributions to noncontrolling interest holders, net									0	0	0
Repurchase of treasury shares									0	0	0
Exercise of stock options									0	0	0
Contingent consideration payment										0
Employee withholding tax on share-based payments and other									0	0	0
Intercompany financing activities									4,605	5,159	5,983
Cash used for financing activities									4,605	5,159	5,983
Effect of exchange rate changes on cash									0	0	0
Net change in cash, cash equivalents, and restricted cash									0	0	0
Cash, cash equivalents, and restricted cash at beginning of year				0				0	0	0	0
Cash, cash equivalents, and restricted cash at end of year	0				0				0	0	0
S&P Global Inc. | Reportable Legal Entities
Operating Activities:
Net income									3,323	3,540	3,670
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation									44	46	31
Amortization of intangibles									0	0	0
Provision for losses on accounts receivable									5	3	2
Deferred income taxes									24	33	108
Stock-based compensation									27	28	35
Gain on dispositions									(49)
Accrued legal settlements										0	0
Pension settlement charge, net of taxes									85
Other									64	46	34
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable									(72)	(27)	(2)
Prepaid and other current assets									17	(2)	(5)
Accounts payable and accrued expenses									14	(11)	22
Unearned revenue									56	(53)	19
Accrued legal settlements									0	0	0
Other current liabilities									(61)	(22)	(42)
Net change in prepaid/accrued income taxes									(33)	2	41
Net change in other assets and liabilities									(74)	(128)	7
Cash provided by operating activities									3,370	3,455	3,920
Investing Activities:
Capital expenditures									(46)	(81)	(55)
Acquisitions, net of cash acquired									0	0	0
Proceeds from dispositions									85	0	0
Changes in short-term investments									0	0	0
Cash used for investing activities									39	(81)	(55)
Financing Activities:
Proceeds from issuance of senior notes, net									1,086	489
Payments on senior notes									(868)	(403)
Dividends paid to shareholders									(560)	(503)	(421)
Distributions to noncontrolling interest holders, net									0	0	0
Repurchase of treasury shares									(1,240)	(1,660)	(1,001)
Exercise of stock options									36	26	68
Contingent consideration payment										0
Employee withholding tax on share-based payments and other									(64)	(66)	(49)
Intercompany financing activities									(1,368)	(1,190)	(2,546)
Cash used for financing activities									(2,978)	(3,307)	(3,949)
Effect of exchange rate changes on cash									5	(5)	5
Net change in cash, cash equivalents, and restricted cash									436	62	(79)
Cash, cash equivalents, and restricted cash at beginning of year				694				632	694	632	711
Cash, cash equivalents, and restricted cash at end of year	1,130				694				1,130	694	632
Standard & Poor's Financial Services LLC | Reportable Legal Entities
Operating Activities:
Net income									880	784	649
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation									12	7	11
Amortization of intangibles									0	0	0
Provision for losses on accounts receivable									4	4	3
Deferred income taxes									(10)	10	(10)
Stock-based compensation									14	16	22
Gain on dispositions									0
Accrued legal settlements										1	0
Pension settlement charge, net of taxes									0
Other									2	5	19
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable									(49)	39	(23)
Prepaid and other current assets									(35)	(4)	3
Accounts payable and accrued expenses									32	(64)	97
Unearned revenue									28	13	2
Accrued legal settlements									(1)	0	(1)
Other current liabilities									1	(11)	(12)
Net change in prepaid/accrued income taxes									(5)	0	(18)
Net change in other assets and liabilities									34	32	(6)
Cash provided by operating activities									907	832	736
Investing Activities:
Capital expenditures									(3)	(16)	(32)
Acquisitions, net of cash acquired									0	0	0
Proceeds from dispositions									0	0	0
Changes in short-term investments									0	0	0
Cash used for investing activities									(3)	(16)	(32)
Financing Activities:
Proceeds from issuance of senior notes, net									0	0
Payments on senior notes									0	0
Dividends paid to shareholders									0	0	0
Distributions to noncontrolling interest holders, net									0	0	0
Repurchase of treasury shares									0	0	0
Exercise of stock options									0	0	0
Contingent consideration payment										0
Employee withholding tax on share-based payments and other									0	0	0
Intercompany financing activities									(904)	(816)	(704)
Cash used for financing activities									(904)	(816)	(704)
Effect of exchange rate changes on cash									0	0	0
Net change in cash, cash equivalents, and restricted cash									0	0	0
Cash, cash equivalents, and restricted cash at beginning of year				0				0	0	0	0
Cash, cash equivalents, and restricted cash at end of year	0				0				0	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Activities:
Net income									2,705	2,956	3,302
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation									26	31	40
Amortization of intangibles									122	122	98
Provision for losses on accounts receivable									9	14	11
Deferred income taxes									32	38	(98)
Stock-based compensation									37	50	42
Gain on dispositions									0
Accrued legal settlements										0	55
Pension settlement charge, net of taxes									0
Other									27	1	43
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions:
Accounts receivable									(14)	(176)	(171)
Prepaid and other current assets									(63)	5	12
Accounts payable and accrued expenses									27	(31)	(44)
Unearned revenue									172	110	64
Accrued legal settlements									0	(108)	(3)
Other current liabilities									4	(34)	(31)
Net change in prepaid/accrued income taxes									(3)	(9)	9
Net change in other assets and liabilities									23	(33)	14
Cash provided by operating activities									3,104	2,936	3,343
Investing Activities:
Capital expenditures									(66)	(16)	(36)
Acquisitions, net of cash acquired									(91)	(401)	(83)
Proceeds from dispositions									0	6	2
Changes in short-term investments									(10)	(5)	(5)
Cash used for investing activities									(167)	(416)	(122)
Financing Activities:
Proceeds from issuance of senior notes, net									0	0
Payments on senior notes									0	0
Dividends paid to shareholders									0	0	0
Distributions to noncontrolling interest holders, net									(143)	(154)	(111)
Repurchase of treasury shares									0	0	0
Exercise of stock options									4	8	7
Contingent consideration payment										(25)
Employee withholding tax on share-based payments and other									(2)	0	0
Intercompany financing activities									(2,333)	(3,153)	(2,733)
Cash used for financing activities									(2,474)	(3,324)	(2,837)
Effect of exchange rate changes on cash									29	(79)	82
Net change in cash, cash equivalents, and restricted cash									492	(883)	466
Cash, cash equivalents, and restricted cash at beginning of year				$ 1,264				$ 2,147	1,264	2,147	1,681
Cash, cash equivalents, and restricted cash at end of year	$ 1,756				$ 1,264				$ 1,756	$ 1,264	$ 2,147