CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Millions, $ 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, 2016	$ 15,802	$ 36	$ 10,993	$ 5,056	$ (283)	$ 3	$ 15,805
Balance (in shares) at Dec. 31, 2016		389
Increase (Decrease) in Shareholders' Equity
Share-based compensation	41		41				41
Issuance of shares under share-based compensation plans		$ 1
Issuance of shares under share-based compensation plans (in shares)		2
Net loss attributable to controlling interest				(3,127)			(3,127)
Other comprehensive income (loss) attributable to controlling interest					(7)		(7)
Total comprehensive loss attributable to controlling interest	(3,134)						(3,134)
Total comprehensive income (loss) attributable to noncontrolling interest						1
Total comprehensive loss							(3,133)
Other, net	(2)		(3)				(2)
Balance at Dec. 31, 2017	12,707	$ 37	11,031	1,929	(290)	4	12,711
Balance (in shares) at Dec. 31, 2017		391
Increase (Decrease) in Shareholders' Equity
Share-based compensation	45		45				45
Issuance of shares under share-based compensation plans (in shares)		3
Issuance of shares in acquisition transactions	2,123	$ 22	2,101				2,123
Issuance of shares in acquisition transactions (in shares)		216
Equity component of convertible debt instruments	172		172				172
Acquisition of redeemable noncontrolling interest	53		53				53
Allocated Capital for Sale of Noncontrolling Interest			(3)
Allocated capital for transactions with holders of noncontrolling interest	(3)					3
Net loss attributable to controlling interest				(1,996)			(1,996)
Other comprehensive income (loss) attributable to controlling interest					11		11
Total comprehensive loss attributable to controlling interest	(1,985)						(1,985)
Total comprehensive income (loss) attributable to noncontrolling interest						(2)
Total comprehensive loss							(1,987)
Recognition of noncontrolling interest in business combination						33	33
Acquisition of noncontrolling interest						(31)	(31)
Other, net	(5)		(5)				(5)
Balance at Dec. 31, 2018	13,107	$ 59	13,394	(67)	(279)	7	13,114
Balance (in shares) at Dec. 31, 2018		610
Increase (Decrease) in Shareholders' Equity
Share-based compensation	37		37				37
Issuance of shares under share-based compensation plans (in shares)		2
Net loss attributable to controlling interest				(1,255)			(1,255)
Other comprehensive income (loss) attributable to controlling interest					(21)		(21)
Total comprehensive loss attributable to controlling interest	(1,276)						(1,276)
Total comprehensive income (loss) attributable to noncontrolling interest						(2)
Total comprehensive loss							(1,278)
Other, net	(6)		(7)				(6)
Balance at Dec. 31, 2019	$ 11,862	$ 59	$ 13,424	(1,297)	(324)	$ 5	$ 11,867
Balance (in shares) at Dec. 31, 2019		612
Increase (Decrease) in Shareholders' Equity
Effect of adopting accounting standards update				$ 25	$ (24)