CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total controlling interest shareholders' equity	Shares	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive loss	Noncontrolling interest	Total
Balance at Dec. 31, 2018	$ 13,107	$ 59	$ 13,394	$ (67)	$ (279)	$ 7	$ 13,114
Increase (Decrease) in Shareholders' Equity
Share-based compensation	19		19				19
Net loss attributable to controlling interest				(379)			(379)
Other comprehensive income (loss) attributable to controlling interest					8		8
Total comprehensive loss attributable to controlling interest	(371)						(371)
Total comprehensive income (loss) attributable to noncontrolling interest						2
Total comprehensive loss							(369)
Other, net	(7)		(8)				(7)
Balance at Jun. 30, 2019	12,748	59	13,405	(421)	(295)	9	12,757
Balance at Mar. 31, 2019	12,946	59	13,396	(213)	(296)	7	12,953
Increase (Decrease) in Shareholders' Equity
Share-based compensation	10		10				10
Net loss attributable to controlling interest				(208)			(208)
Other comprehensive income (loss) attributable to controlling interest					1		1
Total comprehensive loss attributable to controlling interest	(207)						(207)
Total comprehensive income (loss) attributable to noncontrolling interest						2
Total comprehensive loss							(205)
Other, net	(1)		(1)				(1)
Balance at Jun. 30, 2019	12,748	59	13,405	(421)	(295)	9	12,757
Increase (Decrease) in Shareholders' Equity
Effect of adopting accounting standards update				25	(24)
Balance at Dec. 31, 2019	11,862	59	13,424	(1,297)	(324)	5	11,867
Increase (Decrease) in Shareholders' Equity
Issuance of shares under share-based compensation plans		1
Share-based compensation	15		15				15
Net loss attributable to controlling interest				(889)			(889)
Other comprehensive income (loss) attributable to controlling interest					(5)		(5)
Total comprehensive loss attributable to controlling interest	(894)						(894)
Total comprehensive income (loss) attributable to noncontrolling interest						1
Total comprehensive loss							(893)
Other, net	(2)		(1)				(2)
Balance at Jun. 30, 2020	10,981	60	13,438	(2,188)	(329)	6	10,987
Balance at Mar. 31, 2020	11,469	60	13,431	(1,691)	(331)	6	11,475
Increase (Decrease) in Shareholders' Equity
Share-based compensation	7		7				7
Net loss attributable to controlling interest				(497)			(497)
Other comprehensive income (loss) attributable to controlling interest					2		2
Total comprehensive loss attributable to controlling interest	(495)						(495)
Total comprehensive loss							(495)
Balance at Jun. 30, 2020	$ 10,981	$ 60	$ 13,438	(2,188)	$ (329)	$ 6	$ 10,987
Increase (Decrease) in Shareholders' Equity
Effect of adopting accounting standards update				$ (2)