Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Subtotal	$ 423	$ 421	$ 922	$ 894
Alternative revenue programs, net of amortization	(2)	0	1	(2)
Other accrued (deferred) revenues, net	6	(10)	13	(27)
Total retail revenues	427	411	936	865
Wholesale revenues	16	24	53	52
Other operating revenue	17	14	44	25
Total Revenues	460	449	1,033	942
Gain on Derivative Instruments, Pretax	2	4	13	6
Residential [Member]
Disaggregation of Revenue [Line Items]
Subtotal	205	207	495	475
Commercial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	158	162	312	313
Industrial [Member]
Disaggregation of Revenue [Line Items]
Subtotal	50	39	94	83
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Subtotal	10	13	21	23
Revenue Subject to Refund [Member]
Disaggregation of Revenue [Line Items]
Net tax benefits due to the change in tax rate under the TCJA	$ 5	$ 10	$ 11	$ 25