Supplemental Condensed Consolidating Financial Information (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ 921	$ 1,615	$ 1,089
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(57)	(3,091)	(44)
Purchases of property and equipment	(953)	(853)	(614)
Proceeds from disposition of hospitals and other ancillary operations	155	88
Proceeds from sale of property and equipment	15	50	7
Purchases of available-for-sale securities	(162)	(263)
Proceeds from sales of available-for-sale securities	156	229
Increase in other investments	(205)	(511)	(340)
Net cash used in investing activities	(1,051)	(4,351)	(991)
Cash flows from financing activities:
Proceeds from exercise of stock options	25	65	110
Repurchase of restricted stock shares for payroll tax withholding requirements	(20)	(11)	(15)
Stock buy-back	(159)	(9)	(27)
Deferred financing costs and other debt-related costs	(30)	(276)	(13)
Excess tax benefit relating to stock-based compensation			7
Proceeds from noncontrolling investors in joint ventures	47	10
Redemption of noncontrolling investments in joint ventures	(36)	(158)	(9)
Distributions to noncontrolling investors in joint ventures	(100)	(104)	(76)
Borrowings under credit agreements	4,922	9,131	1,194
Issuance of long-term debt		4,000
Proceeds from receivables facility	206	204	338
Repayments of long-term indebtedness	(5,050)	(9,980)	(1,622)
Net cash (used in) provided by financing activities	(195)	2,872	(113)
Net change in cash and cash equivalents	(325)	136	(15)
Cash and cash equivalents at beginning of period	509	373	388
Cash and cash equivalents at end of period	184	509	373
Parent Company [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(25)	176	(82)
Cash flows from financing activities:
Proceeds from exercise of stock options	25	65	110
Repurchase of restricted stock shares for payroll tax withholding requirements	(20)	(11)	(15)
Stock buy-back	(159)	(9)	(27)
Excess tax benefit relating to stock-based compensation			7
Changes in intercompany balances with affiliates, net	179	(221)	7
Net cash (used in) provided by financing activities	25	(176)	82
Issuer [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	159	319	21
Cash flows from financing activities:
Deferred financing costs and other debt-related costs	(30)	(276)	(13)
Changes in intercompany balances with affiliates, net	(181)	(3,334)	274
Borrowings under credit agreements	4,880	9,081	1,170
Issuance of long-term debt		4,000
Repayments of long-term indebtedness	(4,828)	(9,790)	(1,452)
Net cash (used in) provided by financing activities	(159)	(319)	(21)
Other Guarantor [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	629	971	904
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(25)	(2,876)	(12)
Purchases of property and equipment	(685)	(620)	(492)
Proceeds from disposition of hospitals and other ancillary operations	21	3
Proceeds from sale of property and equipment	10	40	4
Purchases of available-for-sale securities	(53)	(23)
Proceeds from sales of available-for-sale securities	46	24
Increase in other investments	(164)	(392)	(275)
Net cash used in investing activities	(850)	(3,844)	(775)
Cash flows from financing activities:
Changes in intercompany balances with affiliates, net	(71)	3,041	(157)
Borrowings under credit agreements	34	50	23
Repayments of long-term indebtedness	(82)	(88)	(28)
Net cash (used in) provided by financing activities	(119)	3,003	(162)
Net change in cash and cash equivalents	(340)	130	(33)
Cash and cash equivalents at beginning of period	365	235	268
Cash and cash equivalents at end of period	25	365	235
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	158	149	246
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(32)	(215)	(32)
Purchases of property and equipment	(268)	(233)	(122)
Proceeds from disposition of hospitals and other ancillary operations	134	85
Proceeds from sale of property and equipment	5	10	3
Purchases of available-for-sale securities	(109)	(240)
Proceeds from sales of available-for-sale securities	110	205
Increase in other investments	(41)	(119)	(65)
Net cash used in investing activities	(201)	(507)	(216)
Cash flows from financing activities:
Proceeds from noncontrolling investors in joint ventures	47	10
Redemption of noncontrolling investments in joint ventures	(36)	(158)	(9)
Distributions to noncontrolling investors in joint ventures	(100)	(104)	(76)
Changes in intercompany balances with affiliates, net	73	514	(124)
Borrowings under credit agreements	8		1
Proceeds from receivables facility	206	204	338
Repayments of long-term indebtedness	(140)	(102)	(142)
Net cash (used in) provided by financing activities	58	364	(12)
Net change in cash and cash equivalents	15	6	18
Cash and cash equivalents at beginning of period	144	138	120
Cash and cash equivalents at end of period	$ 159	$ 144	$ 138