Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 15,112,864	$ 13,619,538	$ 45,897,865	$ 41,280,234
Gross outpatient revenues		8,841,452	7,739,413	26,386,711	23,104,716
Total net revenues		3,963,027	3,562,774	11,714,213	10,578,430
Income/(loss) before allocation of corporate overhead and income taxes		341,533	220,507	1,059,625	659,303
Allocation of corporate overhead		0	0	0	0
Income before income taxes		341,533	220,507	1,059,625	659,303
Total assets		14,353,848	13,873,470	14,353,848	13,873,470	$ 13,967,602
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		12,277,563	10,916,060	37,522,395	33,278,396
Gross outpatient revenues		8,573,270	7,480,353	25,553,451	22,292,249
Total net revenues		2,245,517	2,017,288	6,604,007	5,993,899
Income/(loss) before allocation of corporate overhead and income taxes		199,316	132,406	616,503	396,229
Allocation of corporate overhead		(64,883)	(66,355)	(194,616)	(199,943)
Income before income taxes		134,433	66,051	421,887	196,286
Total assets		6,481,922	6,252,434	6,481,922	6,252,434
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,835,301	2,703,478	8,375,470	8,001,838
Gross outpatient revenues	[1]	268,182	259,060	833,260	812,467
Total net revenues	[1]	1,714,914	1,542,695	5,102,290	4,575,378
Income/(loss) before allocation of corporate overhead and income taxes	[1]	318,864	262,168	999,282	792,217
Allocation of corporate overhead	[1]	(46,898)	(46,677)	(140,808)	(139,998)
Income before income taxes	[1]	271,966	215,491	858,474	652,219
Total assets	[1]	7,631,827	7,372,995	7,631,827	7,372,995
Other
Segment Reporting Information [Line Items]
Total net revenues		2,596	2,791	7,916	9,153
Income/(loss) before allocation of corporate overhead and income taxes		(176,647)	(174,067)	(556,160)	(529,143)
Allocation of corporate overhead		111,781	113,032	335,424	339,941
Income before income taxes		(64,866)	(61,035)	(220,736)	(189,202)
Total assets		$ 240,099	$ 248,041	$ 240,099	$ 248,041

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $230 million and $203 million for the three-month periods ended September 30, 2024 and 2023, respectively, and approximately $651 million and $561 million for the nine-month periods ended September 30, 2024 and 2023, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.442 billion and $1.260 billion as of September 30, 2024 and 2023, respectively.