Supplemental Condensed Consolidating Financial Information (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ 504	$ 514
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(27)	(3,041)
Purchases of property and equipment	(474)	(361)
Proceeds from disposition of hospitals and other ancillary operations	62	12
Proceeds from sale of property and equipment	11	3
Purchases of available-for-sale securities	(90)	(137)
Proceeds from sales of available-for-sale securities	86	123
Increase in other investments	(80)	(251)
Net cash used in investing activities	(512)	(3,652)
Cash flows from financing activities:
Proceeds from exercise of stock options	22	14
Repurchase of restricted stock shares for payroll tax withholding requirements	(20)	(11)
Deferred financing costs and other debt-related costs	(30)	(269)
Excess tax benefit relating to stock-based compensation		3
Proceeds from noncontrolling investors in joint ventures		10
Redemption of noncontrolling investments in joint ventures	(14)	(6)
Distributions to noncontrolling investors in joint ventures	(48)	(44)
Borrowings under credit agreements	2,385	7,488
Issuance of long-term debt		4,000
Proceeds from receivables facility	91	133
Repayments of long-term indebtedness	(2,522)	(8,164)
Net cash (used in) provided by financing activities	(136)	3,154
Net change in cash and cash equivalents	(144)	16
Cash and cash equivalents at beginning of period	509	373
Cash and cash equivalents at end of period	365	389
Parent Company [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(14)	69
Cash flows from financing activities:
Proceeds from exercise of stock options	22	14
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	12	(75)
Net cash (used in) provided by financing activities	14	(69)
Subsidiary Issuer [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(81)	196
Cash flows from financing activities:
Deferred financing costs and other debt-related costs	(30)	(269)
Changes in intercompany balances with affiliates, net	137	(3,282)
Borrowings under credit agreements	2,355	7,455
Issuance of long-term debt		4,000
Repayments of long-term indebtedness	(2,381)	(8,100)
Net cash (used in) provided by financing activities	81	(196)
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	285	392
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(22)	(2,828)
Purchases of property and equipment	(348)	(282)
Proceeds from disposition of hospitals and other ancillary operations	4
Proceeds from sale of property and equipment	8	2
Purchases of available-for-sale securities	(32)
Proceeds from sales of available-for-sale securities	30
Increase in other investments	(63)	(185)
Net cash used in investing activities	(423)	(3,293)
Cash flows from financing activities:
Changes in intercompany balances with affiliates, net	(33)	2,855
Borrowings under credit agreements	30	20
Repayments of long-term indebtedness	(37)	(6)
Net cash (used in) provided by financing activities	(40)	2,869
Net change in cash and cash equivalents	(178)	(32)
Cash and cash equivalents at beginning of period	368	238
Cash and cash equivalents at end of period	190	206
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	314	(143)
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(5)	(213)
Purchases of property and equipment	(126)	(79)
Proceeds from disposition of hospitals and other ancillary operations	58	12
Proceeds from sale of property and equipment	3	1
Purchases of available-for-sale securities	(58)	(137)
Proceeds from sales of available-for-sale securities	56	123
Increase in other investments	(17)	(66)
Net cash used in investing activities	(89)	(359)
Cash flows from financing activities:
Proceeds from noncontrolling investors in joint ventures		10
Redemption of noncontrolling investments in joint ventures	(14)	(6)
Distributions to noncontrolling investors in joint ventures	(48)	(44)
Changes in intercompany balances with affiliates, net	(116)	502
Borrowings under credit agreements		13
Proceeds from receivables facility	91	133
Repayments of long-term indebtedness	(104)	(58)
Net cash (used in) provided by financing activities	(191)	550
Net change in cash and cash equivalents	34	48
Cash and cash equivalents at beginning of period	141	135
Cash and cash equivalents at end of period	$ 175	$ 183