Fair Value Measurements (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended			3 Months Ended				3 Months Ended		1 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Mar. 31, 2013 NUG contracts	Mar. 31, 2013 FES	Mar. 31, 2012 FES	Dec. 31, 2012 FES	Mar. 31, 2013 FES	Mar. 31, 2013 Senior Notes FE	Mar. 31, 2013 Senior Notes FES	Mar. 31, 2013 Senior Notes Allegheny Energy Inc	Mar. 31, 2013 Senior Notes FES Corp and Allegheny Energy Inc	Mar. 31, 2013 Senior Notes, 2.75% Due 2018 Senior Notes FE	Mar. 31, 2013 Senior Notes, 4.25% Due 2023 Senior Notes FE	Mar. 31, 2013 Senior Notes, 3.50% Due 2023 Senior Notes Met-Ed	Mar. 31, 2013 Senior Notes, 4.80% Due 2015 Senior Notes FES	Mar. 31, 2013 Senior Notes, 4.95% Due 2013 Senior Notes, 3.50% Due 2023 Senior Notes Met-Ed
Fair Value of Financial Instruments [Line Items]
Debt Instrument, Face Amount									$ 1,500				$ 650	$ 850	$ 300
Period of future observable data to determine contract price				3 years
Investment excludes Receivables, Payables and Accrued income	(10)		110		(6)		94
Cash balance excluded from available for sale securities	266		326		133		196
Investments not required to be disclosed	640		644
Debt Instrument, Interest Rate, Stated Percentage													2.75%	4.25%	3.50%	4.80%	4.95%
Debt Instrument, Repurchase Amount										0	294
Debt Instrument, Repurchased Face Amount																	150
Payments of Debt Redemption Premiums										0	43
Debt Instrument, Repurchase Notice Amount																400
Loss on debt redemptions	$ (119)	$ 0			$ (73)	$ 0		$ (73)				$ 119