Taxes (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes in unrecognized tax benefits
Beginning balance	$ 48	$ 43	$ 117
Current year increases	4		2
Current year decreases			(7)
Prior years increases	5	10	6
Prior years decreases	(23)	(5)	(37)
Decrease for settlements			(38)
Ending balance	34	48	43
FES
Changes in unrecognized tax benefits
Beginning balance	3	3	45
Current year increases	0		0
Current year decreases			0
Prior years increases	0	0	6
Prior years decreases	0	0	(13)
Decrease for settlements			(35)
Ending balance	$ 3	$ 3	$ 3