Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Supplemental Condensed Consolidating Statement of Operations and Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Feb. 28, 2018	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
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											$ 0	$ 0
Total revenue		$ 863	$ 855	$ 845	$ 837	$ 886	$ 821	$ 845	$ 812	$ 3,400	3,363	3,084
Cost of revenues		339	317	321	307	341	301	316	297	1,284	1,255	1,164
Selling, general and administrative										707	697	613
Research and development										188	202	184
Depreciation, amortization and impairments										647	690	683
Restructuring and other										28	253	46
Operating income										546	266	394
Interest expense										(589)	(597)	(610)
Loss on debt financing transactions	$ (93)	40		(60)						(100)	(93)	(38)
Gain on remeasurement of debt		12	(19)	3	(5)	14	(4)	35	(1)	9	43	0
Other income (expense), net										26	42	27
Net (loss) income before income taxes										(108)	(339)	(227)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										(108)	(339)	(227)
Income (Loss) from Equity in Income of Subsidiaries										0
Income tax expense										(10)	(13)	(15)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		(37)	18	(75)	(24)	207	(352)	(6)	(202)	(118)	(352)	(242)
Net Income (Loss) Attributable to Noncontrolling Interest										12
Net (loss) income attributable to SGC		$ (43)	$ 14	$ (77)	$ (24)	$ 207	$ (352)	$ (6)	$ (202)	(130)	(352)	(242)
Other comprehensive income										8	(100)	134
Total comprehensive loss										(110)	(452)	(108)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										12	0	0
Comprehensive (loss) income attributable to SGC										(122)	(452)	(108)
Reportable Legal Entities | Parent Company
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											(219)	(45)
Total revenue										0	0	0
Cost of revenues										0	0	0
Selling, general and administrative										132	154	127
Research and development										0	0	2
Depreciation, amortization and impairments										53	44	72
Restructuring and other										4	195	30
Operating income										(189)	(393)	(231)
Interest expense										0	0	(5)
Loss on debt financing transactions										0	0	(1)
Gain on remeasurement of debt										0	0
Other income (expense), net										191	336	88
Net (loss) income before income taxes											(57)	(149)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										2
Income (Loss) from Equity in Income of Subsidiaries										(109)
Income tax expense										(23)	(76)	(48)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										(130)
Net Income (Loss) Attributable to Noncontrolling Interest										0
Net (loss) income attributable to SGC										(130)	(352)	(242)
Other comprehensive income										8	(100)	134
Total comprehensive loss										(122)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0
Comprehensive (loss) income attributable to SGC										(122)	(452)	(108)
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											(28)	22
Total revenue										1,538	1,654	1,684
Cost of revenues										446	490	511
Selling, general and administrative										223	227	244
Research and development										86	87	101
Depreciation, amortization and impairments										392	440	463
Restructuring and other										6	9	7
Operating income										385	401	358
Interest expense										0	0	0
Loss on debt financing transactions										0	0	0
Gain on remeasurement of debt										0	0
Other income (expense), net										(660)	(745)	(185)
Net (loss) income before income taxes											(344)	173
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										(275)
Income (Loss) from Equity in Income of Subsidiaries										6
Income tax expense										65	82	(86)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										(204)
Net Income (Loss) Attributable to Noncontrolling Interest										0
Net (loss) income attributable to SGC										(204)	(290)	109
Other comprehensive income										(2)	(66)	66
Total comprehensive loss										(206)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0
Comprehensive (loss) income attributable to SGC										(206)	(356)	175
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											0	0
Total revenue										1,648	1,540	1,223
Cost of revenues										776	721	629
Selling, general and administrative										360	326	250
Research and development										97	112	74
Depreciation, amortization and impairments										180	188	128
Restructuring and other										17	50	4
Operating income										218	143	138
Interest expense										(1)	(1)	(1)
Loss on debt financing transactions										0	0	0
Gain on remeasurement of debt										0	0
Other income (expense), net										(91)	(84)	(26)
Net (loss) income before income taxes											58	111
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										126
Income (Loss) from Equity in Income of Subsidiaries										0
Income tax expense										(44)	(19)	(39)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										82
Net Income (Loss) Attributable to Noncontrolling Interest										12
Net (loss) income attributable to SGC										70	39	72
Other comprehensive income										(1)	(114)	129
Total comprehensive loss										81
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										12
Comprehensive (loss) income attributable to SGC										69	(75)	201
Reportable Legal Entities | SGI
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											44	67
Total revenue										590	547	498
Cost of revenues										387	361	342
Selling, general and administrative										35	42	41
Research and development										5	3	7
Depreciation, amortization and impairments										40	33	31
Restructuring and other										1	(1)	5
Operating income										122	109	72
Interest expense										(588)	(596)	(604)
Loss on debt financing transactions										(100)	(93)	(37)
Gain on remeasurement of debt										9	43
Other income (expense), net										586	535	150
Net (loss) income before income taxes											(2)	(419)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										29
Income (Loss) from Equity in Income of Subsidiaries										8
Income tax expense										(8)	0	158
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										29
Net Income (Loss) Attributable to Noncontrolling Interest										0
Net (loss) income attributable to SGC										29	42	(194)
Other comprehensive income										9	30	10
Total comprehensive loss										38
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0
Comprehensive (loss) income attributable to SGC										38	72	(184)
Eliminating Entries
Condensed Financial Statements, Captions [Line Items]
Income (Loss) from Subsidiaries, before Tax											203	(44)
Total revenue										(376)	(378)	(321)
Cost of revenues										(325)	(317)	(318)
Selling, general and administrative										(43)	(52)	(49)
Research and development										0	0	0
Depreciation, amortization and impairments										(18)	(15)	(11)
Restructuring and other										0	0	0
Operating income										10	6	57
Interest expense										0	0	0
Loss on debt financing transactions										0	0	0
Gain on remeasurement of debt										0	0
Other income (expense), net										0	0	0
Net (loss) income before income taxes											6	57
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest										10
Income (Loss) from Equity in Income of Subsidiaries										95
Income tax expense										0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest										105
Net Income (Loss) Attributable to Noncontrolling Interest										0
Net (loss) income attributable to SGC										105	209	13
Other comprehensive income										(6)	150	(205)
Total comprehensive loss										99
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0
Comprehensive (loss) income attributable to SGC										$ 99	$ 359	$ (192)