Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Subtotal	$ 543	$ 500
Alternative revenue programs, net of amortization	(3)	9
Other accrued (deferred) revenues, net	13	5
Total retail revenues	553	514
Wholesale revenues	33	47
Other operating revenue	23	12
Total revenues	609	573
Gain on Derivative Instruments, Pretax	5	16
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	310	279
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	162	159
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	60	51
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	$ 11	$ 11