Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Currently payable (receivable)-
Federal									$ (16)	$ 14	$ (1)
State									17	20	9
Currently payable (receivable) Total									1	34	8
Deferred, net-
Federal									252	1,647	317
State									243	40	208
Deferred Tax Total									495	1,687	525
Investment tax credit amortization									(6)	(6)	(6)
Total income taxes	$ (13)	$ 133	$ 121	$ 249	$ 1,232	$ 202	$ 132	$ 149	490	$ 1,715	$ 527
Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Currently payable (receivable)-
State									1
Deferred, net-
Federal									1,300
State									$ 12