Discontinued Operations - Major Classes of Cash Flow Items from Discontinued Operations (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations	[1]	$ (35)	$ 1,188
Depreciation and amortization, including regulatory assets, net, intangible assets and deferred debt-related costs		345	280
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions		(554)	(583)
Sales of investment securities held in trusts		153	300
Purchases of investment securities held in trusts		(162)	(322)
FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations		(35)	1,188
Depreciation and amortization, including regulatory assets, net, intangible assets and deferred debt-related costs		0	64
Unrealized gain on derivative transactions		0	(10)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions		0	(16)
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 $5 million and $(871) million for the three months ended March 31, 2019 and 2018, respectively.