Supplemental Condensed Consolidating Financial Information (Schedule of Condensed Consolidating Statement of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ 639	$ 441
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(3,041)	(34)
Purchases of property and equipment	(560)	(421)
Proceeds from disposition of ancillary operations	12
Proceeds from sale of property and equipment	40	4
Purchases of available-for-sale securities	(198)
Proceeds from sales of available-for-sale securities	191
Increase in other investments	(387)	(234)
Net cash used in investing activities	(3,943)	(685)
Cash flows from financing activities:
Proceeds from exercise of stock options	42	109
Repurchase of restricted stock shares for payroll tax withholding requirements	(11)	(15)
Stock buy-back		(27)
Deferred financing costs and other debt-related costs	(272)	(13)
Excess tax benefit relating to stock-based compensation	4	7
Proceeds from noncontrolling investors in joint ventures	10
Redemption of noncontrolling investments in joint ventures	(8)	(6)
Distributions to noncontrolling investors in joint ventures	(74)	(60)
Borrowings under credit agreements	8,348	814
Issuance of long-term debt	4,000
Proceeds from receivables facility	204	320
Repayments of long-term indebtedness	(9,091)	(1,129)
Net cash provided by financing activities	3,152
Net change in cash and cash equivalents	(152)	(244)
Cash and cash equivalents at beginning of period	373	388
Cash and cash equivalents at end of period	221	144
Parent Company [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	96	(81)
Cash flows from financing activities:
Proceeds from exercise of stock options	42	109
Repurchase of restricted stock shares for payroll tax withholding requirements	(11)	(15)
Stock buy-back		(27)
Excess tax benefit relating to stock-based compensation	4	7
Changes in intercompany balances with affiliates, net	(131)	7
Net cash provided by financing activities	(96)	81
Subsidiary Issuer [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	144	6
Cash flows from financing activities:
Deferred financing costs and other debt-related costs	(272)	(13)
Changes in intercompany balances with affiliates, net	(3,195)	183
Borrowings under credit agreements	8,307	792
Issuance of long-term debt	4,000
Repayments of long-term indebtedness	(8,984)	(968)
Net cash provided by financing activities	(144)	(6)
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	657	495
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(2,840)	(9)
Purchases of property and equipment	(390)	(356)
Proceeds from sale of property and equipment	33	1
Purchases of available-for-sale securities	(23)
Proceeds from sales of available-for-sale securities	24
Increase in other investments	(284)	(191)
Net cash used in investing activities	(3,480)	(555)
Cash flows from financing activities:
Changes in intercompany balances with affiliates, net	2,665	(196)
Borrowings under credit agreements	38	21
Repayments of long-term indebtedness	(54)	(20)
Net cash provided by financing activities	2,649	(195)
Net change in cash and cash equivalents	(174)	(255)
Cash and cash equivalents at beginning of period	238	272
Cash and cash equivalents at end of period	64	17
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(258)	21
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(201)	(25)
Purchases of property and equipment	(170)	(65)
Proceeds from disposition of ancillary operations	12
Proceeds from sale of property and equipment	7	3
Purchases of available-for-sale securities	(175)
Proceeds from sales of available-for-sale securities	167
Increase in other investments	(103)	(43)
Net cash used in investing activities	(463)	(130)
Cash flows from financing activities:
Proceeds from noncontrolling investors in joint ventures	10
Redemption of noncontrolling investments in joint ventures	(8)	(6)
Distributions to noncontrolling investors in joint ventures	(74)	(60)
Changes in intercompany balances with affiliates, net	661	6
Borrowings under credit agreements	3	1
Proceeds from receivables facility	204	320
Repayments of long-term indebtedness	(53)	(141)
Net cash provided by financing activities	743	120
Net change in cash and cash equivalents	22	11
Cash and cash equivalents at beginning of period	135	116
Cash and cash equivalents at end of period	$ 157	$ 127