Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Subtotal	$ 499	$ 473
Alternative revenue programs, net of amortization	3	(2)
Other accrued (deferred) revenues, net	7	17
Total retail revenues	509	454
Wholesale revenues	37	28
Other operating revenue	27	11
Total Revenues	573	493
Gain on Derivative Instruments, Pretax	11	2
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	290	268
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	154	151
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	44	44
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	11	10
Revenue Subject to Refund [Member]
Disaggregation of Revenue [Line Items]
Net tax benefits due to the change in tax rate under the TCJA	$ 6	$ 15