Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Subtotal	$ 494	$ 428	$ 1,037	$ 928
Alternative revenue programs, net of amortization	(8)	0	(11)	9
Other accrued (deferred) revenues, net		(1)	(11)	(6)
Total retail revenues	484	429	1,037	943
Wholesale revenues	41	27	74	74
Other operating revenue	12	13	35	25
Total revenues	537	469	1,146	1,042
Gain on Derivative Instruments, Pretax	4	8	9	24
Other Cost of Operating Revenue	2
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	249	223	559	502
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	170	140	332	299
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	62	53	122	104
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	$ 13	$ 12	$ 24	$ 23