Asset Impairments (Details 2) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Impairment	$ 9,218	$ 42
Total	29,387	37,214
FES
Finite-Lived Intangible Assets [Line Items]
Impairment	8,082	33
Total	1,555	$ 9,703
OVEC | AE Supply
Finite-Lived Intangible Assets [Line Items]
Impairment	37
Coal generation assets
Finite-Lived Intangible Assets [Line Items]
Impairment	4,058
Coal generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Impairment	3,264
Nuclear generation assets
Finite-Lived Intangible Assets [Line Items]
Impairment	4,382
Nuclear generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Impairment	4,365
Gas/Hydro generation assets
Finite-Lived Intangible Assets [Line Items]
Impairment	266
Gas/Hydro generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Impairment	0
Nuclear Fuel
Finite-Lived Intangible Assets [Line Items]
Impairment	243
Nuclear Fuel | FES
Finite-Lived Intangible Assets [Line Items]
Impairment	243
Other
Finite-Lived Intangible Assets [Line Items]
Impairment	269
Other | FES
Finite-Lived Intangible Assets [Line Items]
Impairment	210
Materials and Supplies
Finite-Lived Intangible Assets [Line Items]
Impairment	142
Coal contracts | AE Supply
Finite-Lived Intangible Assets [Line Items]
Impairment	55
Net Book Value
Finite-Lived Intangible Assets [Line Items]
Total	11,786
Net Book Value | FES
Finite-Lived Intangible Assets [Line Items]
Total	9,541
Net Book Value | Coal generation assets
Finite-Lived Intangible Assets [Line Items]
Total	4,672
Net Book Value | Coal generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	3,699
Net Book Value | Nuclear generation assets
Finite-Lived Intangible Assets [Line Items]
Total	4,842
Net Book Value | Nuclear generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	4,825
Net Book Value | Gas/Hydro generation assets
Finite-Lived Intangible Assets [Line Items]
Total	1,187
Net Book Value | Gas/Hydro generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	0
Net Book Value | Nuclear Fuel
Finite-Lived Intangible Assets [Line Items]
Total	703
Net Book Value | Nuclear Fuel | FES
Finite-Lived Intangible Assets [Line Items]
Total	703
Net Book Value | Other
Finite-Lived Intangible Assets [Line Items]
Total	382
Net Book Value | Other | FES
Finite-Lived Intangible Assets [Line Items]
Total	314
Fair Value
Finite-Lived Intangible Assets [Line Items]
Total	2,568
Fair Value | FES
Finite-Lived Intangible Assets [Line Items]
Total	1,459
Fair Value | Coal generation assets
Finite-Lived Intangible Assets [Line Items]
Total	614
Fair Value | Coal generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	435
Fair Value | Nuclear generation assets
Finite-Lived Intangible Assets [Line Items]
Total	460
Fair Value | Nuclear generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	460
Fair Value | Gas/Hydro generation assets
Finite-Lived Intangible Assets [Line Items]
Total	921
Fair Value | Gas/Hydro generation assets | FES
Finite-Lived Intangible Assets [Line Items]
Total	0
Fair Value | Nuclear Fuel
Finite-Lived Intangible Assets [Line Items]
Total	460
Fair Value | Nuclear Fuel | FES
Finite-Lived Intangible Assets [Line Items]
Total	460
Fair Value | Other
Finite-Lived Intangible Assets [Line Items]
Total	113
Fair Value | Other | FES
Finite-Lived Intangible Assets [Line Items]
Total	$ 104