Short-Term Borrowings and Bank Lines of Credit (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	$ 5,000
Available Liquidity	4,343
Cash, Available Liquidity	49
Total Available Liquidity	4,392
Revolving Credit Facility
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	500
FirstEnergy | Revolving Credit Facility
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	2,000	[1]
Available Liquidity	1,395	[1]
FES / AE Supply | Revolving Credit Facility
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	2,500
Available Liquidity	2,498
TrAIL | Revolving Credit Facility
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	450
Available Liquidity	450
AGC | Revolving Credit Facility
Short-term Debt [Line Items]
Maximum amount borrowed under revolving credit facility	50
Available Liquidity	$ 0

[1] FE and the Utilities