Pension and Other Postemployment Benefits (Details) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2018 USD ($)	Jul. 31, 2018 employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Additional funding contributions	$ 750
FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amount billed for pension and OPEB service costs			$ 14		$ 28
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs			56	$ 52	168	$ 156
Interest costs			93	97	279	291
Expected return on plan assets			(144)	(112)	(432)	(336)
Amortization of prior service costs (credits)			2	2	6	6
Special termination costs			21	0	21	0
Net periodic costs (credits), including amounts capitalized			28	39	42	117
Net periodic costs (credits), recognized in earnings			5	30	(27)	89
Pension | FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic costs (credits), including amounts capitalized				16	13	47
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs			1	1	3	3
Interest costs			6	7	18	21
Expected return on plan assets			(7)	(7)	(22)	(22)
Amortization of prior service costs (credits)			(20)	(20)	(60)	(60)
Special termination costs			6	0	6	0
Net periodic costs (credits), including amounts capitalized			(14)	(19)	(55)	(58)
Net periodic costs (credits), recognized in earnings			$ (15)	(14)	(57)	(43)
OPEB | FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic costs (credits), including amounts capitalized				$ (8)	$ (10)	$ (24)
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by employer	$ 500
FE Tomorrow Initiative
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of employees that accepted a voluntary enhanced retirement package | employee		500
Percentage of employees that accepted the voluntary enhanced retirement package		80.00%