Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Subtotal	$ 428	$ 423	$ 928	$ 922
Alternative revenue programs, net of amortization	0	(2)	9	1
Other accrued (deferred) revenues, net	1	6	6	13
Total retail revenues	429	427	943	936
Wholesale revenues	27	16	74	53
Other operating revenue	13	17	25	44
Total revenues	469	460	1,042	1,033
Gain on Derivative Instruments, Pretax	8	2	24	13
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	223	205	502	495
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	140	158	299	312
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	53	50	104	94
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	$ 12	$ 10	$ 23	$ 21