Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Net revenues		$ 12,642,117	$ 11,558,897	$ 11,378,259
Percentage of Net Revenue		100.00%	100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,654,119	$ 1,690,591	$ 1,889,245
Percentage of Net Revenue		13.00%	15.00%	17.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,362,962	$ 1,104,930	$ 1,047,759
Percentage of Net Revenue		11.00%	10.00%	9.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,291,692	$ 1,202,632	$ 1,207,649
Percentage of Net Revenue		10.00%	10.00%	11.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,947,263	$ 1,715,439	$ 1,678,641
Percentage of Net Revenue		15.00%	15.00%	15.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,957,027	$ 3,426,937	$ 3,634,817
Percentage of Net Revenue		31.00%	30.00%	32.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 687,725	$ 584,000	$ 553,831
Percentage of Net Revenue		5.00%	5.00%	5.00%
Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 843,200	$ 745,344	$ 696,566
Percentage of Net Revenue		7.00%	6.00%	6.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 898,129	$ 1,089,024	$ 669,751
Percentage of Net Revenue		7.00%	9.00%	6.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		$ 7,108,254	$ 6,337,304	$ 6,164,560
Percentage of Net Revenue		100.00%	100.00%	100.00%
Acute Care Hospital Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,292,205	$ 1,242,268	$ 1,336,200
Percentage of Net Revenue		18.00%	20.00%	22.00%
Acute Care Hospital Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,118,901	$ 869,488	$ 827,216
Percentage of Net Revenue		16.00%	14.00%	13.00%
Acute Care Hospital Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 539,741	$ 551,551	$ 519,508
Percentage of Net Revenue		8.00%	9.00%	8.00%
Acute Care Hospital Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 618,727	$ 491,234	$ 560,029
Percentage of Net Revenue		9.00%	8.00%	9.00%
Acute Care Hospital Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,521,089	$ 2,146,018	$ 2,271,002
Percentage of Net Revenue		35.00%	34.00%	37.00%
Acute Care Hospital Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 0	$ 0	$ 0
Percentage of Net Revenue		0.00%	0.00%	0.00%
Acute Care Hospital Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 358,458	$ 248,047	$ 191,422
Percentage of Net Revenue		5.00%	4.00%	3.00%
Acute Care Hospital Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 659,133	$ 788,698	$ 459,183
Percentage of Net Revenue		9.00%	12.00%	7.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	$ 5,503,644	$ 5,208,722	$ 5,210,063
Percentage of Net Revenue		100.00%	100.00%	100.00%
Behavioral Health Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 361,914	$ 448,323	$ 553,045
Percentage of Net Revenue		7.00%	9.00%	11.00%
Behavioral Health Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 244,061	$ 235,442	$ 220,543
Percentage of Net Revenue		4.00%	5.00%	4.00%
Behavioral Health Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 751,951	$ 651,081	$ 688,141
Percentage of Net Revenue		14.00%	12.00%	13.00%
Behavioral Health Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,328,536	$ 1,224,205	$ 1,118,612
Percentage of Net Revenue		24.00%	24.00%	21.00%
Behavioral Health Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,435,938	$ 1,280,919	$ 1,363,815
Percentage of Net Revenue		26.00%	25.00%	26.00%
Behavioral Health Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 687,725	$ 584,000	$ 553,831
Percentage of Net Revenue		12.00%	11.00%	11.00%
Behavioral Health Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 484,742	$ 497,297	$ 505,144
Percentage of Net Revenue		9.00%	10.00%	10.00%
Behavioral Health Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 208,777	$ 287,455	$ 206,932
Percentage of Net Revenue		4.00%	6.00%	4.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues		$ 30,219	$ 12,871	$ 3,636
Other | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 30,219	$ 12,871	$ 3,636

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $688 million in 2021, $584 million in 2020 and $554 million in 2019.  Total assets at our U.K. behavioral health care facilities were approximately $1.351 billion as of December 31, 2021, $1.334 billion as of December 31, 2020 and $1.270 billion as of December 31, 2019. In addition, included in our 2019 Behavioral Health Services operating segment Income (loss) before allocation of corporate overhead and income taxes is a pre-tax $98 million provision for asset impairment to reduce the carrying value of a tradename intangible asset and real property assets.