Taxes (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accumulated deferred income taxes
Property basis differences	$ 7,088	$ 9,920
Deferred sale and leaseback gain	(351)	(360)
Pension and OPEB	(1,347)	(1,541)
Nuclear decommissioning activities	635	480
Asset retirement obligations	(669)	(731)
Regulatory asset/liability	545	763
Deferred compensation	(269)	(239)
Loss carryforwards and AMT credits	(2,251)	(1,965)
Valuation reserve	438	192
All other	(54)	254
Net deferred income tax liability	3,765	6,773
FES
Accumulated deferred income taxes
Property basis differences	(1,009)	1,901
Deferred sale and leaseback gain	(328)	(342)
Pension and OPEB	(366)	(393)
Lease market valuation liability	111	95
Nuclear decommissioning activities	540	483
Asset retirement obligations	(453)	(509)
Loss carryforwards and AMT credits	(830)	(687)
Valuation reserve	197	46
All other	(141)	6
Net deferred income tax liability		$ 600
Net deferred income tax liability (asset)	$ (2,279)