Financial Risk Management Activities (Schedule Of Reconciliation For Derivative Activity Included In Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosures [Line Items]
(Gain) Loss Reclassified into Income, pre-tax	$ 338	$ 15	$ 365	$ 36
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	59	(48)	77	(166)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	243	10	260	23
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			32		0
(Gain) Loss Reclassified into Income, pre-tax			(3)		5
Pre-Tax Balance at End of Period	25		25		(4)
After-Tax Balance at Beginning of Period			(3)	(6)	(6)
Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss), Net of Tax	13	0	23	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(2)	$ 1	(2)	$ 2	3
After-Tax Balance at End of Period	$ 18		$ 18		$ (3)