Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 1,774	$ 1,378
Capital investments	(1,713)	(1,728)
Proceeds from sale of property and equipment	20	3
Transfers from restricted cash		9
Other	6	4
Net cash used in investing activities	(1,687)	(1,712)
Payments on current portion of long-term debt	(1)	(1)
Payments on revolving long-term debt	(3,573)	(2,135)
Borrowings under revolving long-term debt	3,429	2,378
Other Items		57
Net cash provided by (used in) financing activities	(90)	299
Increase (decrease) in cash and cash equivalents	(3)	(35)
Cash and cash equivalents at beginning of year	23	54
Cash and cash equivalents at end of period	20	19
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		(33)
Capital investments		(29)
Transfers from restricted cash		9
Other		(1)
Net cash used in investing activities		(21)
Intercompany activities		(275)
Payments on current portion of long-term debt		(1)
Payments on revolving long-term debt		(2,135)
Borrowings under revolving long-term debt		2,378
Other Items		57
Net cash provided by (used in) financing activities		24
Increase (decrease) in cash and cash equivalents		(30)
Cash and cash equivalents at beginning of year		48
Cash and cash equivalents at end of period		18
Former Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		1,062
Capital investments		(1,531)
Other		(2)
Net cash used in investing activities		(1,533)
Intercompany activities		465
Net cash provided by (used in) financing activities		465
Increase (decrease) in cash and cash equivalents		(6)
Cash and cash equivalents at beginning of year		6
Other Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		349
Capital investments		(168)
Proceeds from sale of property and equipment		3
Other		7
Net cash used in investing activities		(158)
Intercompany activities		(190)
Net cash provided by (used in) financing activities		(190)
Increase (decrease) in cash and cash equivalents		1
Cash and cash equivalents at end of period		$ 1