Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Effective Income Tax Rate	418.00%	40.00%	113.00%	39.00%
Unrecognized tax expenses	$ (21)		$ (21)		$ (20)
Portion of unrecognized tax expenses that, if recognized, would increase the effective income tax rate	0		0		0
Interest accrued on unrecognized tax expenses	(7)		(7)		(7)
Period of time for possible decrease in unrecognized tax benefits (in months)			twelve
Deferred Tax Liabilities, Goodwill and Intangible Assets	225		225
Deferred income taxes			289	95
Midstream Partnership [Member]
Deferred income taxes	$ (27)