Taxes (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in unrecognized tax benefits
Beginning balance	$ 84	$ 34	$ 34
Current year increases	2	2	3
Prior years increases		69	7
Prior years decreases		(21)	(10)
Decrease for lapse in statute	(6)
Ending balance	80	84	34
FES
Changes in unrecognized tax benefits
Beginning balance	0	8	3
Current year increases	0	0	0
Prior years increases		0	5
Prior years decreases		(8)	0
Decrease for lapse in statute	0
Ending balance	$ 0	$ 0	$ 8