Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Revision of Prior Period Accounting Standards Update Adjustment [Member]	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings (Deficit) [Member]	Retained Earnings (Deficit) [Member] Revision of Prior Period Accounting Standards Update Adjustment [Member]	Total Company Stockholders' Equity [Member]	Total Company Stockholders' Equity [Member] Revision of Prior Period Accounting Standards Update Adjustment [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2019	$ 7,846	$ (5)	$ 4	$ 8,507	$ (1,423)	$ 690	$ (5)	$ 7,778	$ (5)	$ 68
Begining Balance, shares at Dec. 31, 2019			386
Net income (loss)	(2,049)					(2,047)		(2,047)		(2)
Other comprehensive income (loss)	(232)				(232)			(232)
Cash dividends, per common share	$ (19)					$ (19)		$ (19)
Accounting Standards Update Extensible List	us-gaap:AccountingStandardsUpdate201802Member					us-gaap:AccountingStandardsUpdate201802Member		us-gaap:AccountingStandardsUpdate201802Member
Stock-based compensation	$ 27			27				$ 27
Common stock issued, shares			2
Withholding taxes	(18)			(18)				(18)
Other	2									2
Ending Balance at Mar. 31, 2020	5,552		$ 4	8,516	(1,655)	$ (1,381)		5,484		68
Ending Balance, shares at Mar. 31, 2020			388
Beginning Balance at Dec. 31, 2019	7,846	$ (5)	$ 4	8,507	(1,423)	690	$ (5)	7,778	$ (5)	68
Begining Balance, shares at Dec. 31, 2019			386
Net income (loss)	(2,189)
Cash dividends, per common share	(19)
Ending Balance at Sep. 30, 2020	5,540		$ 4	8,567	(1,577)	(1,529)		5,465		75
Ending Balance, shares at Sep. 30, 2020			388
Beginning Balance at Mar. 31, 2020	5,552		$ 4	8,516	(1,655)	(1,381)		5,484		68
Begining Balance, shares at Mar. 31, 2020			388
Net income (loss)	(87)					(93)		(93)		6
Other comprehensive income (loss)	42				42			42
Stock-based compensation	27			27				27
Other	(1)									(1)
Ending Balance at Jun. 30, 2020	5,533		$ 4	8,543	(1,613)	(1,474)		5,460		73
Ending Balance, shares at Jun. 30, 2020			388
Net income (loss)	(53)					(55)		(55)		2
Other comprehensive income (loss)	36				36			36
Cash dividends, per common share	0
Stock-based compensation	24			24				24
Ending Balance at Sep. 30, 2020	5,540		$ 4	8,567	(1,577)	(1,529)		5,465		75
Ending Balance, shares at Sep. 30, 2020			388
Beginning Balance at Dec. 31, 2020	5,279		$ 4	8,591	(1,509)	(1,876)		5,210		69
Begining Balance, shares at Dec. 31, 2020			388
Net income (loss)	(114)					(115)		(115)		1
Other comprehensive income (loss)	(21)				(21)			(21)
Stock-based compensation	20			20				20
Common stock issued, shares			2
Withholding taxes	(13)			(13)				(13)
Other	(1)									(1)
Ending Balance at Mar. 31, 2021	5,150		$ 4	8,598	(1,530)	(1,991)		5,081		69
Ending Balance, shares at Mar. 31, 2021			390
Beginning Balance at Dec. 31, 2020	5,279		$ 4	8,591	(1,509)	(1,876)		5,210		69
Begining Balance, shares at Dec. 31, 2020			388
Net income (loss)	(202)
Cash dividends, per common share	0
Ending Balance at Sep. 30, 2021	5,078		$ 4	8,637	(1,545)	(2,086)		5,010		68
Ending Balance, shares at Sep. 30, 2021			391
Beginning Balance at Mar. 31, 2021	5,150		$ 4	8,598	(1,530)	(1,991)		5,081		69
Begining Balance, shares at Mar. 31, 2021			390
Net income (loss)	(23)					(26)		(26)		3
Other comprehensive income (loss)	33				33			33
Stock-based compensation	20			20				20
Common stock issued, shares			1
Other	(2)									(2)
Ending Balance at Jun. 30, 2021	5,178		$ 4	8,618	(1,497)	(2,017)		5,108		70
Ending Balance, shares at Jun. 30, 2021			391
Net income (loss)	(65)					(69)		(69)		4
Other comprehensive income (loss)	(48)				(48)			(48)
Cash dividends, per common share	0
Stock-based compensation	19			19				19
Other	(6)									(6)
Ending Balance at Sep. 30, 2021	$ 5,078		$ 4	$ 8,637	$ (1,545)	$ (2,086)		$ 5,010		$ 68
Ending Balance, shares at Sep. 30, 2021			391