Stockholders' Deficit - Schedule of Stockholders' Deficit (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Equity, beginning balance	$ (1,595)	$ (1,538)	$ (2,136)	$ (2,141)
Redeemable Noncontrolling Interests, beginning balance		484
Comprehensive income (loss)	14	(59)	87	28
Distributions to noncontrolling interests	(14)	(9)	(10)	(8)
Purchase of subsidiary shares from noncontrolling interests			1	(1)
Other reclassifications of noncontrolling interests	(1)			(8)
Adjustment to redemption value of redeemable noncontrolling interests	(25)	7	3	(7)
Cancellation of restricted stock for tax withholdings on vested shares		(4)		(1)
Share-based compensation	5	8	3	2
Equity, ending balance	(1,616)	(1,595)	(2,052)	(2,136)
Redeemable Noncontrolling Interests, ending balance	498
Redeemable Noncontrolling Interests (Non- Equity)
Redeemable Noncontrolling Interests, beginning balance	481	484	502	502
Comprehensive income (loss) attributable to redeemable noncontrolling interest	24	21	7	8
Distributions to redeemable noncontrolling interests	(31)	(12)	(17)	(22)
Purchase of subsidiary shares from noncontrolling interests	(2)		(1)	(1)
Dispositions of less-than-wholly owned business		(7)
Noncontrolling interest in acquired entity		2
Other reclassifications of noncontrolling interests	1
Other reclassifications of redeemable noncontrolling interests			1	8
Adjustment to redemption value of redeemable noncontrolling interests	25	(7)	(3)	7
Redeemable Noncontrolling Interests, ending balance	498	481	489	502
Common Stock
Equity, beginning balance	1	1	1	1
Equity, ending balance	1	1	1	1
Additional Paid-in Capital
Equity, beginning balance	2,105	2,094	2,001	2,008
Purchase of subsidiary shares from noncontrolling interests			1	(1)
Other reclassifications of noncontrolling interests	(1)
Adjustment to redemption value of redeemable noncontrolling interests	(25)	7	3	(7)
Cancellation of restricted stock for tax withholdings on vested shares		(4)		(1)
Share-based compensation	5	8	3	2
Equity, ending balance	2,084	2,105	2,008	2,001
Accumulated Other Comprehensive (Income) Loss
Equity, beginning balance	(16)	(13)	(7)	(9)
Comprehensive income (loss)	1	(3)	2	2
Equity, ending balance	(15)	(16)	(5)	(7)
Accumulated Deficit
Equity, beginning balance	(3,771)	(3,707)	(4,200)	(4,218)
Comprehensive income (loss)	6	(64)	69	18
Equity, ending balance	(3,765)	(3,771)	(4,131)	(4,200)
Noncontrolling Interest
Equity, beginning balance	86	87	69	77
Comprehensive income (loss)	7	8	16	8
Distributions to noncontrolling interests	(14)	(9)	(10)	(8)
Other reclassifications of noncontrolling interests				(8)
Equity, ending balance	$ 79	$ 86	$ 75	$ 69