Discontinued Operations - Major Classes of Cash Flow Items (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations	[1]	$ (29)	$ (9)	$ (64)	$ 1,179
Depreciation and amortization, including regulatory assets, net, intangible assets and deferred debt-related costs				702	604
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions		(674)	(724)	(1,228)	(1,307)
Sales of investment securities held in trusts				302	475
Purchases of investment securities held in trusts				(322)	(508)
FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations		$ (29)	$ (9)	(64)	1,179
Depreciation and amortization, including regulatory assets, net, intangible assets and deferred debt-related costs				0	80
Unrealized gain on derivative transactions				0	(10)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				0	(23)
Sales of investment securities held in trusts				0	109
Purchases of investment securities held in trusts				$ 0	$ (122)

[1] Net of income tax expense (benefits) of $39 million and $(16) million for the three months ended June 30, 2019 and 2018, respectively, and $44 million and $(887) million for the six months ended June 30, 2019 and 2018, respectively.