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				6 Months Ended
		Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022	Jun. 30, 2021
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments						$ 862	$ 1,229
Net Gains (Losses) on Trust Investments		$ (187)		$ 81		(255)	141
Nuclear Decommissioning Trust (NDT) Fund [Member]
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments	[1]	341		538		814	1,135
Gross Realized Gains		21		83		50	162
Gross Realized Losses		(31)		(23)		(65)	(38)
Net Realized Gains (Losses)	[2]	(10)		60		(15)	124
Unrealized Gain (Loss) on Equity Securities		(170)		20		(231)	13
Net Gains (Losses) on Trust Investments		(180)		80		(246)	137
Rabbi Trust [Member]
Schedule of Trust Investments [Line Items]
Proceeds from Sale of Trust Investments		20	[1]	29	[1]	48	94
Gross Realized Gains		2		2		3	7
Gross Realized Losses		(4)		(1)		(6)	(3)
Net Realized Gains (Losses)	[3]	(2)		1		(3)	4
Unrealized Gain (Loss) on Equity Securities		(5)		0		(6)	0
Net Gains (Losses) on Trust Investments		$ (7)		$ 1		$ (9)	$ 4

[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.