Consolidated Statements Of Equity (Deficit) - USD ($) shares in Thousands, $ in Millions	Common Stock [Member] Previously Reported [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Previously Reported [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member] Previously Reported [Member]	Accumulated Deficit [Member] Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member] Previously Reported [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Common Stock [Member] Previously Reported [Member]	Treasury Common Stock [Member]	Previously Reported [Member]	Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Total
Balance at Dec. 31, 2018	$ 27		$ 4,802		$ (2,752)	$ 11	$ 79	$ (463)	$ (79)	$ (14)		$ 1,600	$ 11
Common Stock Balance (in shares) at Dec. 31, 2018	106,025									(489)
Stock plans				$ 3										$ 3
Stock plans (in shares)											(229)
Net income (loss)							(87)							(87)
Other comprehensive income, net of tax									8					8
Balance at Mar. 31, 2019		$ 27		4,805			(2,749)		(534)		$ (14)			1,535
Common Stock Balance (in shares) at Mar. 31, 2019		106,025									(718)
Balance at Dec. 31, 2018	$ 27		$ 4,802		$ (2,752)	$ 11	79	(463)	(79)	$ (14)		$ 1,600	$ 11
Common Stock Balance (in shares) at Dec. 31, 2018	106,025									(489)
Net income (loss)														(5,749)
Other comprehensive income, net of tax									25					25
Balance at Sep. 30, 2019		$ 27		4,810			(8,411)		(517)		$ (12)			(4,103)
Common Stock Balance (in shares) at Sep. 30, 2019		106,025									(655)
Balance at Mar. 31, 2019		$ 27		4,805			(2,749)		(534)		$ (14)			1,535
Common Stock Balance (in shares) at Mar. 31, 2019		106,025									(718)
Stock plans											$ 2			2
Stock plans (in shares)											68
Net income (loss)							(5,317)							(5,317)
Other comprehensive income, net of tax									9					9
Balance at Jun. 30, 2019		$ 27		4,805			(8,066)		(525)		$ (12)			(3,771)
Common Stock Balance (in shares) at Jun. 30, 2019		106,025									(650)
Stock plans				5										5
Stock plans (in shares)											(5)
Net income (loss)							(345)							(345)
Other comprehensive income, net of tax									8					8
Balance at Sep. 30, 2019		$ 27		4,810			(8,411)		(517)		$ (12)			(4,103)
Common Stock Balance (in shares) at Sep. 30, 2019		106,025									(655)
Balance at Dec. 31, 2019		$ 27		4,815			(8,573)	(650)	(650)		$ (13)			$ (4,394)
Common Stock Balance (in shares) at Dec. 31, 2019		106,025									(894)			105,131
Stock plans				1										$ 1
Stock plans (in shares)											(143)
Net income (loss)							(186)							(186)
Other comprehensive income, net of tax									86					86
Balance at Mar. 31, 2020		$ 27		4,816			(8,759)		(564)		$ (13)			(4,493)
Common Stock Balance (in shares) at Mar. 31, 2020		106,025									(1,037)
Balance at Dec. 31, 2019		$ 27		4,815			(8,573)	$ (650)	(650)		$ (13)			$ (4,394)
Common Stock Balance (in shares) at Dec. 31, 2019		106,025									(894)			105,131
Net income (loss)														$ (352)
Other comprehensive income, net of tax									(182)					(182)
Balance at Sep. 30, 2020		$ 27		4,818			(8,925)		(832)		$ (14)			$ (4,926)
Common Stock Balance (in shares) at Sep. 30, 2020		106,025									(1,232)			104,793
Balance at Mar. 31, 2020		$ 27		4,816			(8,759)		(564)		$ (13)			$ (4,493)
Common Stock Balance (in shares) at Mar. 31, 2020		106,025									(1,037)
Stock plans (in shares)											(77)
Net income (loss)							(181)							(181)
Other comprehensive income, net of tax									(423)					(423)
Balance at Jun. 30, 2020		$ 27		4,816			(8,940)		(987)		$ (13)			(5,097)
Common Stock Balance (in shares) at Jun. 30, 2020		106,025									(1,114)
Stock plans				2							$ (1)			1
Stock plans (in shares)											(118)
Net income (loss)							15							15
Other comprehensive income, net of tax									155					155
Balance at Sep. 30, 2020		$ 27		$ 4,818			$ (8,925)		$ (832)		$ (14)			$ (4,926)
Common Stock Balance (in shares) at Sep. 30, 2020		106,025									(1,232)			104,793