Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 1,194	$ 878
Capital investments	(1,144)	(1,176)
Transfers from restricted cash		9
Other	3	6
Net cash used in investing activities	(1,124)	(1,161)
Payments on current portion of long-term debt	(1)	(1)
Payments on revolving long-term debt	(2,486)	(1,233)
Borrowings under revolving long-term debt	2,375	1,463
Other Items		26
Net cash provided by (used in) financing activities	(73)	255
Increase (decrease) in cash and cash equivalents	(3)	(28)
Cash and cash equivalents at beginning of year	23	54
Cash and cash equivalents at end of period	20	26
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		(29)
Capital investments		(13)
Transfers from restricted cash		9
Net cash used in investing activities		(4)
Intercompany activities		(244)
Payments on current portion of long-term debt		(1)
Payments on revolving long-term debt		(1,233)
Borrowings under revolving long-term debt		1,463
Other Items		26
Net cash provided by (used in) financing activities		11
Increase (decrease) in cash and cash equivalents		(22)
Cash and cash equivalents at beginning of year		48
Cash and cash equivalents at end of period		26
Former Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		651
Capital investments		(1,084)
Other		2
Net cash used in investing activities		(1,082)
Intercompany activities		425
Net cash provided by (used in) financing activities		425
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		256
Capital investments		(79)
Other		4
Net cash used in investing activities		(75)
Intercompany activities		(181)
Net cash provided by (used in) financing activities		$ (181)