Capitalization (Details 4) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Schedule of Capitalization [Line Items]
Aggregate LOC Amount	$ 93
Annual Fees	1.25%
Applicable interest coverage	$ 1
FES
Schedule of Capitalization [Line Items]
Aggregate LOC Amount	$ 93
Annual Fees	1.25%