Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 15,120,215	$ 13,631,215	$ 30,785,001	$ 27,660,696
Gross outpatient revenues		8,920,442	7,796,816	17,545,259	15,365,303
Total net revenues		3,907,604	3,548,138	7,751,186	7,015,656
Income/(loss) before allocation of corporate overhead and income taxes		382,006	224,695	718,092	438,796
Allocation of corporate overhead		0	0	0	0
Income before income taxes		382,006	224,695	718,092	438,796
Total assets		14,071,428	13,732,309	14,071,428	13,732,309	$ 13,967,602
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		12,334,730	10,960,845	25,244,832	22,362,336
Gross outpatient revenues		8,633,892	7,515,780	16,980,181	14,811,896
Total net revenues		2,173,409	2,003,079	4,358,490	3,976,611
Income/(loss) before allocation of corporate overhead and income taxes		211,720	130,527	417,188	263,823
Allocation of corporate overhead		(64,887)	(66,326)	(129,733)	(133,588)
Income before income taxes		146,833	64,201	287,455	130,235
Total assets		6,338,360	6,108,389	6,338,360	6,108,389
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,785,485	2,670,370	5,540,169	5,298,360
Gross outpatient revenues	[1]	286,550	281,036	565,078	553,407
Total net revenues	[1]	1,731,309	1,542,194	3,387,376	3,032,683
Income/(loss) before allocation of corporate overhead and income taxes	[1]	360,480	263,693	680,418	530,049
Allocation of corporate overhead	[1]	(46,975)	(46,679)	(93,910)	(93,321)
Income before income taxes	[1]	313,505	217,014	586,508	436,728
Total assets	[1]	7,572,228	7,365,545	7,572,228	7,365,545
Other
Segment Reporting Information [Line Items]
Total net revenues		2,886	2,865	5,320	6,362
Income/(loss) before allocation of corporate overhead and income taxes		(190,194)	(169,525)	(379,514)	(355,076)
Allocation of corporate overhead		111,862	113,005	223,643	226,909
Income before income taxes		(78,332)	(56,520)	(155,871)	(128,167)
Total assets		$ 160,840	$ 258,375	$ 160,840	$ 258,375

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $213 million and $190 million for the three-month periods ended June 30, 2024 and 2023, respectively, and approximately $421 million and $358 million for the six-month periods ended June 30, 2024 and 2023, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.36 billion and $1.295 billion as of June 30, 2024 and 2023, respectively.