Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Reporting of Segments
Gross inpatient revenues	$ 4,423,652	$ 4,196,022	$ 13,568,872	$ 13,088,818
Gross outpatient revenues	1,683,524	1,544,462	5,120,771	4,563,300
Total net revenues	1,680,353	1,662,675	5,196,473	5,097,226
Income/(loss) before allocation of corporate overhead and income taxes	123,505	147,076	530,267	533,501
Allocation of corporate overhead	0	0	0	0
Income/(loss) after allocation of corporate overhead and before income taxes	123,505	147,076	530,267	533,501
Total assets	7,781,066	7,605,931	7,781,066	7,605,931	7,665,245
Acute Care Hospital Services [Member]
Reporting of Segments
Gross inpatient revenues	3,013,482	2,827,617	9,326,344	8,934,701
Gross outpatient revenues	1,517,261	1,384,084	4,606,680	4,068,566
Total net revenues	828,399	831,775	2,598,527	2,587,070
Income/(loss) before allocation of corporate overhead and income taxes	48,925	57,027	240,375	275,156
Allocation of corporate overhead	39,360	35,094	118,082	98,418
Income/(loss) after allocation of corporate overhead and before income taxes	9,565	21,933	122,293	176,738
Total assets	2,987,293	2,797,029	2,987,293	2,797,029
Behavioral Health Services [Member]
Reporting of Segments
Gross inpatient revenues	1,410,170	1,368,405	4,242,528	4,154,117
Gross outpatient revenues	151,788	146,836	474,623	453,652
Total net revenues	841,669	825,825	2,572,256	2,493,336
Income/(loss) before allocation of corporate overhead and income taxes	200,711	184,304	628,170	559,681
Allocation of corporate overhead	20,533	15,438	62,665	46,854
Income/(loss) after allocation of corporate overhead and before income taxes	180,178	168,866	565,505	512,827
Total assets	4,459,030	4,421,040	4,459,030	4,421,040
Other [Member]
Reporting of Segments
Gross inpatient revenues
Gross outpatient revenues	14,475	13,542	39,468	41,082
Total net revenues	10,285	5,075	25,690	16,820
Income/(loss) before allocation of corporate overhead and income taxes	(126,131)	(94,255)	(338,278)	(301,336)
Allocation of corporate overhead	(59,893)	(50,532)	(180,747)	(145,272)
Income/(loss) after allocation of corporate overhead and before income taxes	(66,238)	(43,723)	(157,531)	(156,064)
Total assets	$ 334,743	$ 387,862	$ 334,743	$ 387,862