Financial Risk Management Activities (Schedule Of Derivative Instruments Not Designated As Hedging Instruments And Impact On Results Of Operations) (Detail) - Energy-Related Contracts [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 338	$ (355)	$ 1,241	$ (1,399)
Operating Revenues [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	339	(354)	1,241	(1,398)
Energy Costs [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (1)	$ (1)	$ 0	$ (1)