Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified																						3 Months Ended
	Mar. 31, 2012 FTRs		Dec. 31, 2011 FTRs		Dec. 31, 2010 FTRs		Mar. 31, 2012 FTRs FES	Dec. 31, 2011 FTRs FES	Dec. 31, 2010 FTRs FES	Mar. 31, 2012 Non Utility Generation contract		Dec. 31, 2011 Non Utility Generation contract		Dec. 31, 2010 Non Utility Generation contract		Mar. 31, 2012 Non Utility Generation contract JCP&L		Dec. 31, 2011 Non Utility Generation contract JCP&L		Dec. 31, 2010 Non Utility Generation contract JCP&L		Mar. 31, 2012 Model Level 3 Minimum FTRs	Mar. 31, 2012 Model Level 3 Minimum FTRs FES	Mar. 31, 2012 Model Level 3 Minimum Non Utility Generation contract MWh	Mar. 31, 2012 Model Level 3 Minimum Non Utility Generation contract JCP&L MWh	Mar. 31, 2012 Model Level 3 Maximum FTRs	Mar. 31, 2012 Model Level 3 Maximum FTRs FES	Mar. 31, 2012 Model Level 3 Maximum Non Utility Generation contract MWh	Mar. 31, 2012 Model Level 3 Maximum Non Utility Generation contract JCP&L MWh	Mar. 31, 2012 Model Level 3 Weighted Average [Member] FTRs	Mar. 31, 2012 Model Level 3 Weighted Average [Member] FTRs FES	Mar. 31, 2012 Model Level 3 Weighted Average [Member] Non Utility Generation contract MWh	Mar. 31, 2012 Model Level 3 Weighted Average [Member] Non Utility Generation contract JCP&L MWh
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value	$ (14)	[1]	$ (22)	[1]	$ 0	[1]	$ (3)	$ (6)	$ 0	$ (300)	[1]	$ (292)	[1]	$ (344)	[1]	$ (132)	[2]	$ (143)	[2]	$ (227)	[2]
Fair Value Inputs, RTO Auction Clearing Prices																						(4.18)	(4.18)			9.81	8.03			1.51	0.76
Fair Value Inputs, Generation																								500	69,000			6,809,000	736,000			2,547,000	157,000
Fair Value Inputs, Power, Regional Prices																								58.71	58.71			84.92	84.92			66.77	68.65

[1] Changes in the fair value of NUG contracts are generally subject to regulatory accounting and do not impact earnings.

[2] Changes in the fair value of NUG contracts are subject to regulatory accounting and do not impact earnings.