Segment Reporting (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 46,449,556	$ 40,281,027	$ 38,531,825
Gross outpatient revenues		21,647,468	17,236,319	18,733,333
Total net revenues		12,642,117	11,558,897	11,378,259
Income (loss) before allocation of corporate overhead and income taxes		1,293,313	1,252,083	1,066,337
Allocation of corporate overhead		0	0	0
Income before income taxes		1,293,313	1,252,083	1,066,337
Total assets		13,093,543	13,476,879	11,668,250
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		36,522,155	30,562,093	28,430,922
Gross outpatient revenues		20,633,921	16,272,520	17,666,629
Total net revenues		7,108,254	6,337,304	6,164,560
Income (loss) before allocation of corporate overhead and income taxes		734,666	693,427	713,410
Allocation of corporate overhead		(233,298)	(223,921)	(230,166)
Income before income taxes		501,368	469,506	483,244
Total assets		5,534,912	4,927,456	4,405,643
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	9,927,401	9,718,934	10,100,903
Gross outpatient revenues	[1]	1,013,547	963,799	1,066,704
Total net revenues	[1]	5,503,644	5,208,722	5,210,063
Income (loss) before allocation of corporate overhead and income taxes	[1]	1,025,557	1,023,257	900,965
Allocation of corporate overhead	[1]	(172,512)	(170,849)	(166,571)
Income before income taxes	[1]	853,045	852,408	734,394
Total assets	[1]	7,250,427	7,044,617	6,910,790
Other
Segment Reporting Information [Line Items]
Total net revenues		30,219	12,871	3,636
Income (loss) before allocation of corporate overhead and income taxes		(466,910)	(464,601)	(548,038)
Allocation of corporate overhead		405,810	394,770	396,737
Income before income taxes		(61,100)	(69,831)	(151,301)
Total assets		$ 308,204	$ 1,504,806	$ 351,817

[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.