Derivative and Hedging Activities - Natural Gas and Oil Sales Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
General Discussion of Derivative Instruments and Hedging Activities [Abstract]
Natural gas, oil and NGL sales	$ 6,923	$ 5,359	$ 5,259
Gains on natural gas, oil and NGL derivatives	129	919	772
Gain (Loss) on Price Risk Cash Flow Hedge Ineffectiveness	0	0	(7)
Total natural gas, oil and NGL sales	$ 7,052	$ 6,278	$ 6,024