Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Subtotal	$ 479	$ 448	$ 1,407	$ 1,370
Alternative revenue programs, net of amortization	(9)	4	0	5
Other accrued (deferred) revenues, net	7	4	13	17
Total retail revenues	477	456	1,420	1,392
Wholesale revenues	56	72	130	125
Other operating revenue	14	14	39	58
Total revenues	547	542	1,589	1,575
Gain on Derivative Instruments, Pretax	31	25	55	38
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	245	218	747	713
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	164	167	463	479
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	58	50	162	144
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	$ 12	$ 13	$ 35	$ 34