Taxes (Details 2) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accumulated deferred income taxes
Property basis differences	$ 3,662	$ 7,088
Deferred sale and leaseback gain	(231)	(351)
Pension and OPEB	(952)	(1,347)
Nuclear decommissioning activities	450	635
Asset retirement obligations	(453)	(669)
Regulatory asset/liability	416	545
Deferred compensation	(177)	(269)
Nuclear Fuel	(375)	(90)
Loss carryforwards and AMT credits	(1,467)	(2,251)
Valuation reserve	580	438
All other	(94)	36
Net deferred income tax liability	1,359	3,765
FES
Accumulated deferred income taxes
Property basis differences	(677)	(1,009)
Deferred sale and leaseback gain	(219)	(328)
Pension and OPEB	(244)	(366)
Lease market valuation liability	75	111
Nuclear decommissioning activities	411	540
Asset retirement obligations	(296)	(453)
Nuclear Fuel	(375)	(90)
Loss carryforwards and AMT credits	(587)	(830)
Valuation reserve	268	197
All other	(110)	(51)
Net deferred income tax asset	$ (1,754)	$ (2,279)