Fair Value Measurements (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	$ 1,881	[1]	$ 1,827	[2]
Unrealized Gains	34	[1]	34	[2]
Fair Value	1,915	[1]	1,861	[2]
Equity securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	320	[1]	293	[2]
Unrealized Gains	21	[1]	16	[2]
Fair Value	341	[1]	309	[2]
FES | Debt Securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	836	[1]	778	[2]
Unrealized Gains	14	[1]	14	[2]
Fair Value	850	[1]	792	[2]
FES | Equity securities
Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities
Cost Basis	301	[1]	281	[2]
Unrealized Gains	19	[1]	13	[2]
Fair Value	$ 320	[1]	$ 294	[2]

[1] Excludes short-term cash investments: FE Consolidated - $266 million; FES - $133 million

[2] Excludes short-term cash investments: FE Consolidated - $326 million; FES - $196 million