Financial Risk Management Activities (Schedule Of Reconciliation For Derivative Activity Included In Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosures [Line Items]
(Gain) Loss Reclassified into Income, pre-tax	$ (11)	$ (14)	$ (27)	$ (21)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	0	(53)	18	(118)
(Gain) Loss Reclassified into Income, net of tax	(7)	(8)	(17)	(13)
Cash Flow Hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-Tax Balance at Beginning of Period			(4)	(9)	$ (9)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), pre-tax			14		0
(Gain) Loss Reclassified into Income, pre-tax			0		5
Pre-Tax Balance at End of Period	10		10		(4)
After-Tax Balance at Beginning of Period			(3)	(6)	(6)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	12	0	10	0	0
(Gain) Loss Reclassified into Income, net of tax	1	$ 0	0	$ (1)	3
After-Tax Balance at End of Period	$ 7		$ 7		$ (3)