Stockholders' Deficit - Schedule of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit			$ (2,653)	$ (2,479)	$ (2,358)	$ (2,108)	$ (2,653)	$ (2,108)
Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance			129				129
Vesting of RSUs, net of tax withholdings and other	$ (3)	$ (4)	(13)		1	(1)
Stock-based compensation	22	31	17	17	14	9
Net income (loss) from continuing operations	187	113	(9)	(111)	(198)	(155)	291	$ (464)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(27)	11	8	32	62	(97)
Accounting Standards Update [Extensible List]								us-gaap:AccountingStandardsUpdate201905Member
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(2,191)	(2,370)	(2,521)				(2,191)		$ (2,524)
Stockholders' Equity Attributable to Noncontrolling Interest	144						144
Total SGC stockholders' deficit	(2,335)			(2,541)	(2,479)	(2,358)	(2,335)	$ (2,541)
Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest						(6)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit				1	1	1		1
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1	1	1				1		1
Total SGC stockholders' deficit				1	1	1		1
Additional Paid in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit				1,230	1,216	1,208		1,208
Vesting of RSUs, net of tax withholdings and other	(3)	(4)	(13)		1	(1)
Stock-based compensation	22	31	17	16	13	9
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,318	1,299	1,272				1,318		1,268
Total SGC stockholders' deficit				1,246	1,230	1,216		1,246
Accumulated Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit				(3,322)	(3,119)	(2,954)		(2,954)
Net income (loss) from continuing operations	182	109	(15)		(203)	(159)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		(3,435)	(3,544)						(3,529)
Total SGC stockholders' deficit				(3,439)	(3,322)	(3,119)		(3,439)
Accumulated Loss | Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit						6		6
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest						(6)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit				(175)	(175)	(175)		(175)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(175)	(175)	(175)				(175)		(175)
Total SGC stockholders' deficit				(175)	(175)	(175)		(175)
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total SGC stockholders' deficit				(327)	(389)	(292)		(292)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(27)	11	8	32	62	(97)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(226)	(199)	(210)				(226)		$ (218)
Total SGC stockholders' deficit				(295)	(327)	(389)		(295)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance	139	135	129	114	108	104	129	104
Stock-based compensation				1	1
Net income (loss) from continuing operations					5	4
Less: comprehensive income attributable to noncontrolling interest	5	4	6	6			15	15
Stockholders' Equity Attributable to Noncontrolling Interest	$ 144	$ 139	$ 135	$ 121	$ 114	$ 108	$ 144	$ 121