Trust Investments (Proceeds From The Sales Of And The Net Realized Gains On Securities in the NDT and Rabbi Trusts) (Detail) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023	Sep. 30, 2022
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments						$ 998	$ 1,281
Net Gains (Losses) on Trust Investments		$ (40)		$ (97)		63	(352)
Nuclear Decommissioning Trust (NDT) Fund [Member]
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments	[1]	268		404		972	1,218
Gross Realized Gains		19		13		65	63
Gross Realized Losses		(16)		(38)		(71)	(103)
Net Realized Gains (Losses)	[2]	3		(25)		(6)	(40)
Unrealized Gain (Loss) on Equity Securities		(42)		(70)		69	(301)
Net Gains (Losses) on Trust Investments		(39)		(95)		63	(341)
Rabbi Trust [Member]
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments		9	[1]	15	[1]	26	63
Gross Realized Gains		1		0		5	3
Gross Realized Losses		(1)		(1)		(6)	(7)
Net Realized Gains (Losses)	[3]	0		(1)		(1)	(4)
Unrealized Gain (Loss) on Equity Securities		(1)		(1)		1	(7)
Net Gains (Losses) on Trust Investments		$ (1)		$ (2)		$ 0	$ (11)

[1] Includes activity in accounts related to the liquidation of funds being transitioned within the trust.

[2] The cost of these securities was determined on the basis of specific identification.

[3] The cost of these securities was determined on the basis of specific identification.