Net Gains on Sales of Fixed Assets Narrative (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
Significant Acquisitions and Disposals [Line Items]
Gain (Loss) on Sale of Property Plant Equipment	$ 109	$ 0	$ 158	$ 2
Natural Gas Processing Plant [Member] | Granite Wash Midstream Gas Services, L.L.C. [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	245		245
Gain (Loss) on Sale of Property Plant Equipment	106		106
Gas Gathering and Processing Equipment [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			134
Gain (Loss) on Sale of Property Plant Equipment			$ 56