Schedule of Disaggregates Revenue by Major Source (Parenthetical) (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,155,999,000	$ 2,912,541,000	$ 9,366,866,000	$ 8,471,962,000
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		1,822,027,000	1,610,003,000	5,271,000,000	4,598,558,000
Acute Care Hospital Services | CARES Act and Other Grant Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		2,000,000	4,000,000	13,000,000	161,000,000
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	1,328,293,000	1,299,591,000	4,075,127,000	3,864,823,000
Behavioral Health Services | CARES Act and Other Grant Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 114,000	$ 9,000,000	$ 2,000,000	$ 52,000,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $174 million and $155 million for the three-month periods ended September 30, 2021 and 2020, respectively, and approximately $511 million and $429 million for the nine-month periods ended September 30, 2021 and 2020, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.338 billion and $1.257 billion as of September 30, 2021 and 2020, respectively.