Derivative Instruments (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Derivative [Line Items]
Unamortized gains or losses associated with designated cash flow hedges	$ 14		$ 19
Reclassifications from AOCL into other operating expense	5	(5)
Losses to be amortized to interest expenses during next twelve months	7
Unamortized gains or losses associated with prior interest rate hedges	77
Gains included in long-term debt associated with prior fixed-for-floating interest rate swap agreements	96
Net asset position under commodity derivative contracts	66
Expected adverse change in quoted market prices of derivative instruments	10.00%
Decrease net income due to adverse change in commodity prices	2
Period In Which LSEs May Request Direct Allocation Of FTRs	2 years
FES
Derivative [Line Items]
Collateral posted	44
Additional collateral related to commodity derivatives	16
AE Supply
Derivative [Line Items]
Collateral posted	1
Additional collateral related to commodity derivatives	3
Cash Flow Hedges
Derivative [Line Items]
Losses to be amortized to interest expenses during next twelve months	9
Number of Interest Rate Swap Agreements	0
Reclassifications from accumulated other comprehensive loss	2	3
Fair Value Hedging
Derivative [Line Items]
Losses to be amortized to interest expenses during next twelve months	23
Number of Interest Rate Swap Agreements	0
Reclassifications from long-term debt	6	5
Subject to Regulatory Accounting, Excluded from Earnings | Non Utility Generation contract
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	(7)	(17)
Subject to Regulatory Accounting, Excluded from Earnings | FTRs
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	$ 3	$ (10)