Financial Risk Management Activities (Schedule Of Reconciliation For Derivative Activity Included In Accumulated Other Comprehensive Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Gain (Loss) in AOCI	$ 24		$ (16)	$ 30	$ 11
(Gain) Loss into Income	(10)		9	(8)	15
Cash Flow Hedges [Member]
Pre-Tax Balance at Beginning of Period	0	(4)		(4)
Gain (Loss) in AOCI		(8)
(Gain) Loss into Income	0	12	(1)	12	(7)
Pre-Tax Balance at End of Period	1	0		1
After-Tax Balance at Beginning of Period	0	(2)		(2)
Gain (Loss) in AOCI	1	(5)	0	(4)	0
(Gain) Loss into Income	0	7	0	7	(4)
After-Tax Balance at End of Period	$ 1	$ 0		$ 1