Consolidated Statements of Stockholders' Deficit - USD ($) $ in Millions	Total	Redeemable Noncontrolling Interests (Non- Equity)	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Noncontrolling Interest
Equity, beginning balance at Dec. 31, 2020	$ (1,538)		$ 1	$ 2,094	$ (13)	$ (3,707)	$ 87
Redeemable Noncontrolling Interests, beginning balance at Dec. 31, 2020		$ 484
Shares, outstanding, beginning balance at Dec. 31, 2020			129,612,117
Comprehensive income (loss)	266				(2)	230	38
Comprehensive income (loss) attributable to redeemable noncontrolling interest		100
Contributions from redeemable noncontrolling interests		1
Distributions to noncontrolling interests	(39)
Distributions to redeemable noncontrolling interests		(82)					(39)
Purchase of subsidiary shares from noncontrolling interests	13	(32)		17			(4)
Other reclassifications of noncontrolling interests	1				1
Other reclassifications of redeemable noncontrolling interests		1
Disposition of less-than-wholly owned hospital		(7)
Noncontrolling interests in acquired entity		2
Adjustment to redemption value of redeemable noncontrolling interests	(13)	13		(13)
Cancellation of restricted stock for tax withholdings on vested shares	(5)			(5)
Cancellation of restricted stock for tax withholdings on vested shares, shares			(584,379)
Issuance of common stock in connection with the exercise of stock options, shares			65,499
Stock-based compensation	25			25
Stock-based compensation, shares			3,053,045
Equity, ending balance at Dec. 31, 2021	(1,290)		$ 1	2,118	(14)	(3,477)	82
Redeemable Noncontrolling Interests, ending balance at Dec. 31, 2021		480
Shares, outstanding, ending balance at Dec. 31, 2021			132,146,282
Comprehensive income (loss)	80				(7)	46
Comprehensive income (loss) attributable to redeemable noncontrolling interest		92					41
Contributions from noncontrolling interests	11
Contributions from redeemable noncontrolling interests		2					11
Distributions to noncontrolling interests	(45)
Distributions to redeemable noncontrolling interests		(80)					(45)
Purchase of subsidiary shares from noncontrolling interests	(6)	1		(6)
Noncontrolling interests in acquired entity	3	6					3
Adjustment to redemption value of redeemable noncontrolling interests	(40)	40		(40)
Cancellation of restricted stock for tax withholdings on vested shares	(8)			(8)
Cancellation of restricted stock for tax withholdings on vested shares, shares			(828,952)
Issuance of common stock in connection with the exercise of stock options, shares			56,500
Stock-based compensation	20			20
Stock-based compensation, shares			3,329,887
Equity, ending balance at Dec. 31, 2022	(1,275)		$ 1	2,084	(21)	(3,431)	92
Redeemable Noncontrolling Interests, ending balance at Dec. 31, 2022	541	541
Shares, outstanding, ending balance at Dec. 31, 2022			134,703,717
Comprehensive income (loss)	(50)				7	(133)	76
Comprehensive income (loss) attributable to redeemable noncontrolling interest		73
Contributions from noncontrolling interests	4						4
Contributions from redeemable noncontrolling interests		1
Distributions to noncontrolling interests	(69)						(69)
Distributions to redeemable noncontrolling interests		(72)
Purchase of subsidiary shares from noncontrolling interests	5	(7)		5
Other reclassifications of noncontrolling interests	263			121			142
Other reclassifications of redeemable noncontrolling interests		(266)
Noncontrolling interests in acquired entity		10
Adjustment to redemption value of redeemable noncontrolling interests	(43)	43		(43)
Cancellation of restricted stock for tax withholdings on vested shares	(4)			(4)
Cancellation of restricted stock for tax withholdings on vested shares, shares			(722,606)
Issuance of common stock in connection with the exercise of stock options, shares			15,001
Stock-based compensation	22			22
Stock-based compensation, shares			2,778,799
Equity, ending balance at Dec. 31, 2023	(1,147)		$ 1	$ 2,185	$ (14)	$ (3,564)	$ 245
Redeemable Noncontrolling Interests, ending balance at Dec. 31, 2023	$ 323	$ 323
Shares, outstanding, ending balance at Dec. 31, 2023			136,774,911