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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
(Gain) Loss Reclassified into Income, pre-tax	$ 0	$ 11	$ 4	$ 27
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	(5)	0	3	18
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	1	7	3	17
Cash Flow Hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-Tax Balance at Beginning of Period			4	(4)	$ (4)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), pre-tax			30		13
(Gain) Loss Reclassified into Income, pre-tax			(7)		(5)
Pre-Tax Balance at End of Period	27		27		4
After-Tax Balance at Beginning of Period			3	(3)	(3)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	2	12	22	10	9
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(3)	$ (1)	(5)	$ 0	(3)
After-Tax Balance at End of Period	$ 20		$ 20		$ 3