Discontinued Operations - Major Classes of Cash Flow Items from Discontinued Operations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations	[1]	$ 8	$ 326	$ (1,435)
Gain on disposal, net of tax (Note 3)		(59)	(435)	0
Depreciation and amortization, including nuclear fuel, regulatory assets, net, intangible assets and deferred debt-related costs		1,217	1,384	1,700
Deferred income taxes and investment tax credits, net		252	485	839
Unrealized (gain) loss on derivative transactions		0	(5)	81
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions		(2,665)	(2,675)	(2,587)
Nuclear fuel		0	0	(254)
Sales of investment securities held in trusts		1,637	909	2,170
Purchases of investment securities held in trusts		(1,675)	(963)	(2,268)
FES and FENOC | Discontinued Operations, Disposed of by Means Other than Sale
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations		8	326	(1,435)
Deconsolidation, Gain (Loss), Amount		(59)	(435)	0
Gain on disposal, net of tax (Note 3)			(435)	0
Depreciation and amortization, including nuclear fuel, regulatory assets, net, intangible assets and deferred debt-related costs		0	110	333
Deferred income taxes and investment tax credits, net		47	61	(842)
Unrealized (gain) loss on derivative transactions		0	(10)	81
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions		0	(27)	(317)
Nuclear fuel		0	0	(254)
Sales of investment securities held in trusts		0	109	940
Purchases of investment securities held in trusts		$ 0	$ (122)	$ (999)

[1] Net of income tax benefit of $5 million, $1,251 million, and $820 million in 2019, 2018 and 2017, respectively.