Supplemental Condensed Consolidating Financial Information (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ (61)	$ 65
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(13)	(2,774)
Purchases of property and equipment	(241)	(181)
Proceeds from disposition of hospitals and other ancillary operations	62
Proceeds from sale of property and equipment	3
Purchases of available-for-sale securities	(59)	(78)
Proceeds from sales of available-for-sale securities	56	76
Increase in other investments	(39)	(99)
Net cash used in investing activities	(231)	(3,056)
Cash flows from financing activities:
Proceeds from exercise of stock options	17	6
Repurchase of restricted stock shares for payroll tax withholding requirements	(20)	(11)
Deferred financing costs and other debt-related costs	(20)	(269)
Excess tax benefit relating to stock-based compensation		3
Redemption of noncontrolling investments in joint ventures	(7)	(5)
Distributions to noncontrolling investors in joint ventures	(23)	(19)
Borrowings under credit agreements	1,251	7,079
Issuance of long-term debt		4,000
Proceeds from receivables facility	75	133
Repayments of long-term indebtedness	(1,268)	(7,686)
Net cash provided by financing activities	5	3,231
Net change in cash and cash equivalents	(287)	240
Cash and cash equivalents at beginning of period	509	373
Cash and cash equivalents at end of period	222	613
Parent Company [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(10)	73
Cash flows from financing activities:
Proceeds from exercise of stock options	17	6
Repurchase of restricted stock shares for payroll tax withholding requirements	(20)	(11)
Excess tax benefit relating to stock-based compensation		3
Changes in intercompany balances with affiliates, net	13	(71)
Net cash provided by financing activities	10	(73)
Subsidiary Issuer [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(123)	298
Cash flows from financing activities:
Deferred financing costs and other debt-related costs	(20)	(269)
Changes in intercompany balances with affiliates, net	77	(3,417)
Borrowings under credit agreements	1,250	7,062
Issuance of long-term debt		4,000
Repayments of long-term indebtedness	(1,184)	(7,674)
Net cash provided by financing activities	123	(298)
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	23	62
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(11)	(2,760)
Purchases of property and equipment	(199)	(143)
Proceeds from disposition of hospitals and other ancillary operations	4
Purchases of available-for-sale securities	(22)
Proceeds from sales of available-for-sale securities	19
Increase in other investments	(30)	(75)
Net cash used in investing activities	(239)	(2,978)
Cash flows from financing activities:
Changes in intercompany balances with affiliates, net	(101)	3,117
Borrowings under credit agreements	1	17
Repayments of long-term indebtedness	(15)	(7)
Net cash provided by financing activities	(115)	3,127
Net change in cash and cash equivalents	(331)	211
Cash and cash equivalents at beginning of period	368	239
Cash and cash equivalents at end of period	37	450
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	49	(368)
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(2)	(14)
Purchases of property and equipment	(42)	(38)
Proceeds from disposition of hospitals and other ancillary operations	58
Proceeds from sale of property and equipment	3
Purchases of available-for-sale securities	(37)	(78)
Proceeds from sales of available-for-sale securities	37	76
Increase in other investments	(9)	(24)
Net cash used in investing activities	8	(78)
Cash flows from financing activities:
Redemption of noncontrolling investments in joint ventures	(7)	(5)
Distributions to noncontrolling investors in joint ventures	(23)	(19)
Changes in intercompany balances with affiliates, net	11	371
Proceeds from receivables facility	75	133
Repayments of long-term indebtedness	(69)	(5)
Net cash provided by financing activities	(13)	475
Net change in cash and cash equivalents	44	29
Cash and cash equivalents at beginning of period	141	134
Cash and cash equivalents at end of period	$ 185	$ 163