Financial Risk Management Activities (Schedule Of Reconciliation For Derivative Activity Included In Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2011	Sep. 30, 2011
Financial Risk Management Activities [Abstract]
Balance in AOCI, Beginning of Period, Pre-Tax	$ 188	$ 188
Loss Recognized in AOCI (Effective Portion)	21	(2)
Less: Gain Reclassified into Income (Effective Portion), Pre-Tax	(93)	(60)
Balance in AOCI, End of Period, Pre-Tax	93	54
Balance in AOCI, Beginning of Period, After-Tax	111	111
Gain Recognized in AOCI (Effective Portion), After-Tax	12	(1)
Less: Gain Reclassified into Income (Effective Portion), After-Tax	(56)	(35)
Balance in AOCI, End of Period, After-Tax	$ 54	$ 31