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, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ 65	$ 57
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(2,774)	(5)
Purchases of property and equipment	(181)	(113)
Purchases of available-for-sale securities	(78)
Proceeds from sales of available-for-sale securities	76
Proceeds from sale of property and equipment		1
Increase in other investments	(99)	(69)
Net cash used in investing activities	(3,056)	(186)
Cash flows from financing activities:
Proceeds from exercise of stock options	6	72
Repurchase of restricted stock shares for payroll tax withholding requirements	(11)	(14)
Stock buy-back		(19)
Deferred financing costs and other debt-related costs	(269)	(1)
Excess tax benefit relating to stock-based compensation	3	5
Redemption of noncontrolling investments in joint ventures	(5)
Distributions to noncontrolling investors in joint ventures	(19)	(15)
Borrowings under credit agreements	7,079	101
Issuance of long-term debt	4,000
Proceeds from receivables facility	133	300
Repayments of long-term indebtedness	(7,686)	(403)
Net cash provided by financing activities	3,231	26
Net change in cash and cash equivalents	240	(103)
Cash and cash equivalents at beginning of period	373	388
Cash and cash equivalents at end of period	613	285
Parent Company [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	75	(6)
Cash flows from financing activities:
Proceeds from exercise of stock options	6	72
Repurchase of restricted stock shares for payroll tax withholding requirements	(11)	(14)
Stock buy-back		(19)
Excess tax benefit relating to stock-based compensation	3	5
Changes in intercompany balances with affiliates, net	(73)	(38)
Net cash provided by financing activities	(75)	6
Subsidiary Issuer [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	298	(13)
Cash flows from financing activities:
Deferred financing costs and other debt-related costs	(269)
Changes in intercompany balances with affiliates, net	(3,417)	219
Borrowings under credit agreements	7,062	90
Issuance of long-term debt	4,000
Repayments of long-term indebtedness	(7,674)	(296)
Net cash provided by financing activities	(298)	13
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	60	173
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(2,760)	(4)
Purchases of property and equipment	(143)	(95)
Increase in other investments	(76)	(55)
Net cash used in investing activities	(2,979)	(154)
Cash flows from financing activities:
Changes in intercompany balances with affiliates, net	3,122	(132)
Borrowings under credit agreements	17	11
Repayments of long-term indebtedness	(7)	(6)
Net cash provided by financing activities	3,132	(127)
Net change in cash and cash equivalents	213	(108)
Cash and cash equivalents at beginning of period	238	272
Cash and cash equivalents at end of period	451	164
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(368)	(97)
Cash flows from investing activities:
Acquisitions of facilities and other related equipment	(14)	(1)
Purchases of property and equipment	(38)	(18)
Purchases of available-for-sale securities	(78)
Proceeds from sales of available-for-sale securities	76
Proceeds from sale of property and equipment		1
Increase in other investments	(23)	(14)
Net cash used in investing activities	(77)	(32)
Cash flows from financing activities:
Deferred financing costs and other debt-related costs		(1)
Redemption of noncontrolling investments in joint ventures	(5)
Distributions to noncontrolling investors in joint ventures	(19)	(15)
Changes in intercompany balances with affiliates, net	368	(49)
Proceeds from receivables facility	133	300
Repayments of long-term indebtedness	(5)	(101)
Net cash provided by financing activities	472	134
Net change in cash and cash equivalents	27	5
Cash and cash equivalents at beginning of period	135	116
Cash and cash equivalents at end of period	$ 162	$ 121