Derivative Financial Instruments (Schedule Of Derivative Obligations Under Terminated Hedge Arrangements) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Derivative gains (losses), net	$ (197)	$ (218)	$ 44	$ (322)
Commodity Price Derivatives [Member] | Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains (losses), net	(212)	(226)	39	(340)
Interest Rate Derivatives [Member] | Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains (losses), net	$ 15	$ 8	$ 5	$ 18