Pension and Other Postemployment Benefits (Details 10) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
FES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-current liabilities	$ 866	$ 785
FENOC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-current liabilities	570	518
Pension | FES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (Liability) Asset	(158)	(303)
OPEB | FES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (Liability) Asset	$ 36	$ 25