Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Supplemental Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Financial Statements
Net cash (used in) provided by operating activities	$ 167	$ 30
Cash flows from investing activities:
Capital expenditures	(67)	(88)
Acquisitions of businesses and assets, net of cash acquired	0	(274)
Distributions of capital from equity investments	3	2
Other, principally change in intercompany investing activities	0	0
Net cash used in investing activities	(64)	(360)
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	953	5
Repayment of assumed NYX debt	0	(288)
Payments of debt issuance and deferred financing costs	(14)	(39)
Payments on license obligations	(7)	(7)
Proceeds from Sale of Finance Receivables	11
Net redemptions of common stock under stock-based compensation plans and other	(1)	(17)
Other, principally change in intercompany financing activities	0	0
Net cash provided by (used in) financing activities	942	(346)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	1	2
Increase in cash, cash equivalents and restricted cash	1,046	(674)
Cash, cash equivalents and restricted cash, beginning of period	220	834
Cash, cash equivalents and restricted cash, end of period	1,266	160
Reportable Legal Entities | SGI (Issuer)
Condensed Financial Statements
Net cash (used in) provided by operating activities	55	(25)
Cash flows from investing activities:
Capital expenditures	(10)	(17)
Acquisitions of businesses and assets, net of cash acquired		0
Distributions of capital from equity investments	0	0
Other, principally change in intercompany investing activities	(986)	74
Net cash used in investing activities	(996)	57
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	955	7
Repayment of assumed NYX debt		0
Payments of debt issuance and deferred financing costs	(14)	(39)
Payments on license obligations	0	0
Proceeds from Sale of Finance Receivables	0
Net redemptions of common stock under stock-based compensation plans and other	0	0
Other, principally change in intercompany financing activities	0	0
Net cash provided by (used in) financing activities	941	(32)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash, beginning of period	2	1
Cash, cash equivalents and restricted cash, end of period	2	1
Reportable Legal Entities | SGC (Parent)
Condensed Financial Statements
Net cash (used in) provided by operating activities	(15)	(32)
Cash flows from investing activities:
Capital expenditures	(3)	(8)
Acquisitions of businesses and assets, net of cash acquired		0
Distributions of capital from equity investments	0	0
Other, principally change in intercompany investing activities	0	0
Net cash used in investing activities	(3)	(8)
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	0	0
Repayment of assumed NYX debt		0
Payments of debt issuance and deferred financing costs	0	0
Payments on license obligations	(7)	(7)
Proceeds from Sale of Finance Receivables	0
Net redemptions of common stock under stock-based compensation plans and other	1	(15)
Other, principally change in intercompany financing activities	1,069	(630)
Net cash provided by (used in) financing activities	1,063	(652)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Increase in cash, cash equivalents and restricted cash	1,045	(692)
Cash, cash equivalents and restricted cash, beginning of period	74	732
Cash, cash equivalents and restricted cash, end of period	1,119	40
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Financial Statements
Net cash (used in) provided by operating activities	63	34
Cash flows from investing activities:
Capital expenditures	(25)	(45)
Acquisitions of businesses and assets, net of cash acquired		(9)
Distributions of capital from equity investments	0	0
Other, principally change in intercompany investing activities	(47)	0
Net cash used in investing activities	(72)	(54)
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	0	0
Repayment of assumed NYX debt		0
Payments of debt issuance and deferred financing costs	0	0
Payments on license obligations	0	0
Proceeds from Sale of Finance Receivables	11
Net redemptions of common stock under stock-based compensation plans and other	(2)	(2)
Other, principally change in intercompany financing activities	0	22
Net cash provided by (used in) financing activities	9	20
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Increase in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash, beginning of period	44	44
Cash, cash equivalents and restricted cash, end of period	44	44
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Financial Statements
Net cash (used in) provided by operating activities	65	55
Cash flows from investing activities:
Capital expenditures	(29)	(18)
Acquisitions of businesses and assets, net of cash acquired		(265)
Distributions of capital from equity investments	3	2
Other, principally change in intercompany investing activities	0	0
Net cash used in investing activities	(26)	(281)
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	(2)	(2)
Repayment of assumed NYX debt		(288)
Payments of debt issuance and deferred financing costs	0	0
Payments on license obligations	0	0
Proceeds from Sale of Finance Receivables	0
Net redemptions of common stock under stock-based compensation plans and other	0	0
Other, principally change in intercompany financing activities	(36)	534
Net cash provided by (used in) financing activities	(38)	244
Effect of exchange rate changes on cash, cash equivalents and restricted cash	1	2
Increase in cash, cash equivalents and restricted cash	2	20
Cash, cash equivalents and restricted cash, beginning of period	101	60
Cash, cash equivalents and restricted cash, end of period	103	80
Eliminating Entries
Condensed Financial Statements
Net cash (used in) provided by operating activities	(1)	(2)
Cash flows from investing activities:
Capital expenditures	0	0
Acquisitions of businesses and assets, net of cash acquired		0
Distributions of capital from equity investments	0	0
Other, principally change in intercompany investing activities	1,033	(74)
Net cash used in investing activities	1,033	(74)
Cash flows from financing activities:
Proceeds from long-term debt, net of payments	0	0
Repayment of assumed NYX debt		0
Payments of debt issuance and deferred financing costs	0	0
Payments on license obligations	0	0
Proceeds from Sale of Finance Receivables	0
Net redemptions of common stock under stock-based compensation plans and other	0	0
Other, principally change in intercompany financing activities	(1,033)	74
Net cash provided by (used in) financing activities	(1,033)	74
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Increase in cash, cash equivalents and restricted cash	(1)	(2)
Cash, cash equivalents and restricted cash, beginning of period	(1)	(3)
Cash, cash equivalents and restricted cash, end of period	$ (2)	$ (5)