Taxes (Details 1) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of federal income tax expense at the federal statutory rate to the total provision for income taxes
Income from Continuing Operations, before income taxes									$ 1,117	$ 1,512	$ 1,426
Federal income tax expense at statutory rate (21%, 21%, and 35% for 2019, 2018, and 2017, respectively)									235	318	499
Increases (reductions) in taxes resulting from-
State income taxes, net of federal tax benefit									96	90	40
AFUDC equity and other flow-through									(36)	(31)	(15)
Amortization of investment tax credits									(5)	(5)	(6)
ESOP dividend									(3)	(3)	(5)
Remeasurement of deferred taxes									0	24	1,193
WV unitary group remeasurement									0	126	0
Excess deferred tax amortization due to the Tax Act									(74)	(60)	0
Uncertain tax positions									(11)	2	(3)
Valuation allowances									5	21	11
Other, net									6	8	1
Total income taxes	$ (68)	$ 107	$ 81	$ 93	$ 35	$ 121	$ 101	$ 233	$ 213	$ 490	$ 1,715
Effective income tax rate (percent)									19.10%	32.40%	120.30%