Financial Risk Management Activities (Schedule Of Reconciliation For Derivative Activity Included In Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Financial Risk Management Activities [Abstract]
Balance in AOCI, Beginning of Period, Pre-Tax	$ 188	$ 305
Loss Recognized in AOCI (Effective Portion)	80	102
Less: Gain Reclassified into Income (Effective Portion), Pre-Tax	(214)	(219)
Balance in AOCI, End of Period, Pre-Tax	54	188
Balance in AOCI, Beginning of Period, After-Tax	111	180
Gain Recognized in AOCI (Effective Portion), After-Tax	47	60
Less: Gain Reclassified into Income (Effective Portion), After-Tax	(127)	(129)
Balance in AOCI, End of Period, After-Tax	$ 31	$ 111