TAXES - Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Currently payable (receivable)-
Federal	$ (14)	$ (16)	$ (16)
State	21	24	17
Currently payable (receivable) Total	7	8	1
Deferred, net-
Federal	171	150	252
State	(38)	60	243
Deferred Tax Total	133	210	495
Investment tax credit amortization	(14)	(5)	(6)
Total income taxes	126	213	490
Federal
Deferred, net-
Income tax expense (benefit), continuing operations, discontinued operations	6
State and Local
Deferred, net-
Income tax expense (benefit), continuing operations, discontinued operations			1
Discontinued Operations, Disposed of by Means Other than Sale \| FES and FENOC \| Federal
Deferred, net-
Federal	66	9	1,300
Discontinued Operations, Disposed of by Means Other than Sale \| FES and FENOC \| State and Local
Deferred, net-
Federal	$ 1	$ 4	$ 12

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