Discontinued Operations - Gain on Deconsolidation (Details) - FES and FENOC - Discontinued Operations, Disposed of by Means Other than Sale - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Removal of investment in FES and FENOC		$ 2,193
Assumption of benefit obligations retained at FE	$ 820	(820)
Guarantees and credit support provided by FE		(139)
Reserve on receivables and allocated Pension/OPEB mark-to-market		(914)
Settlement consideration and services credit		(1,197)
Loss on disposal of FES and FENOC, before tax		(877)
Income tax benefit, including estimated worthless stock deduction		1,312
Gain on disposal of FES and FENOC, net of tax		$ 435	$ 0	$ 0