Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 13,619,538	$ 12,458,242	$ 41,280,234	$ 37,402,231
Gross outpatient revenues		7,739,413	6,627,491	23,104,716	19,134,671
Total net revenues		3,562,774	3,336,027	10,578,430	9,952,390
Income/(loss) before allocation of corporate overhead and income taxes		220,507	234,212	659,303	643,925
Allocation of corporate overhead		0	0	0	0
Income before income taxes		220,507	234,212	659,303	643,925
Total assets		13,873,470	13,378,900	13,873,470	13,378,900	$ 13,494,188
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		10,916,060	9,875,794	33,278,396	29,821,756
Gross outpatient revenues		7,480,353	6,379,324	22,292,249	18,360,902
Total net revenues		2,017,288	1,919,678	5,993,899	5,707,510
Income/(loss) before allocation of corporate overhead and income taxes		132,406	129,241	396,229	372,981
Allocation of corporate overhead		(66,355)	(63,242)	(199,943)	(188,739)
Income before income taxes		66,051	65,999	196,286	184,242
Total assets		6,252,434	6,039,787	6,252,434	6,039,787
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,703,478	2,582,448	8,001,838	7,580,475
Gross outpatient revenues	[1]	259,060	248,167	812,467	773,769
Total net revenues	[1]	1,542,695	1,434,828	4,575,378	4,235,215
Income/(loss) before allocation of corporate overhead and income taxes	[1]	262,168	237,949	792,217	693,694
Allocation of corporate overhead	[1]	(46,677)	(44,882)	(139,998)	(134,946)
Income before income taxes	[1]	215,491	193,067	652,219	558,748
Total assets	[1]	7,372,995	7,336,437	7,372,995	7,336,437
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues					0
Gross outpatient revenues					0
Total net revenues		2,791	(18,479)	9,153	9,665
Income/(loss) before allocation of corporate overhead and income taxes		(174,067)	(132,978)	(529,143)	(422,750)
Allocation of corporate overhead		113,032	108,124	339,941	323,685
Income before income taxes		(61,035)	(24,854)	(189,202)	(99,065)
Total assets		$ 248,041	$ 2,676	$ 248,041	$ 2,676

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $203 million and $167 million for the three-month periods ended September 30, 2023 and 2022, respectively, and approximately $561 million and $516 million for the nine-month periods ended September 30, 2023 and 2022, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.260 billion and $1.119 billion as of September 30, 2023 and 2022, respectively.