Derivative Instruments (Details 1)	Dec. 31, 2012 MWh
Power Contracts
Volume of First Energy's outstanding derivative transactions
Purchases (in MWH or BTUs)	23,000,000
Sales (in MWH or BTUs)	44,000,000
Net (in MWH or BTUs)	(21,000,000)
FTRs
Volume of First Energy's outstanding derivative transactions
Purchases (in MWH or BTUs)	46,000,000
Sales (in MWH or BTUs)	0
Net (in MWH or BTUs)	46,000,000
NUGs
Volume of First Energy's outstanding derivative transactions
Purchases (in MWH or BTUs)	15,000,000
Sales (in MWH or BTUs)	0
Net (in MWH or BTUs)	15,000,000
LCAPP
Volume of First Energy's outstanding derivative transactions
Volume of Derivatives, Purchases (in MW)	408,000,000
Volume of Derivatives, Sales (in MW)	0
Volume of Derivatives, Net (in MW)	408,000,000
Natural Gas
Volume of First Energy's outstanding derivative transactions
Purchases (in MWH or BTUs)	25,000,000
Sales (in MWH or BTUs)	0
Net (in MWH or BTUs)	25,000,000