Derivative Instruments (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012 MWh
Power Contracts
Volume of First Energy's outstanding derivative transactions
Purchases, in ones	29,000,000
Sales, in ones	40,000,000
Net, in ones	(11,000,000)
FTRs
Volume of First Energy's outstanding derivative transactions
Purchases, in ones	82,000,000
Sales, in ones	0
Net, in ones	82,000,000
Interest rate swaps
Volume of First Energy's outstanding derivative transactions
Volume of Derivatives, Purchases	1,600
Volume of Derivatives, Sales	0
Volume of Derivatives, Net	1,600
NUGs
Volume of First Energy's outstanding derivative transactions
Purchases, in ones	22,000,000
Sales, in ones	0
Net, in ones	22,000,000
LCAPP
Volume of First Energy's outstanding derivative transactions
Volume of Derivatives, Purchases, in ones	408,000,000
Volume of Derivatives, Sales, in ones	0
Volume of Derivatives, Net, in ones	408,000,000
Natural Gas Futures
Volume of First Energy's outstanding derivative transactions
Purchases, in ones	26,000,000
Sales, in ones	0
Net, in ones	26,000,000