Organization, Basis of Presentation and Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Regulatory assets on the Balance Sheets
Regulatory Assets	$ 2,030,000	$ 1,830,000
OE
Regulatory assets on the Balance Sheets
Regulatory Assets	363,000	403,000
CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	295,284	369,829
TE
Regulatory assets on the Balance Sheets
Regulatory Assets	70,235	72,588
JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	408,000	514,000
Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	328,623	295,908
Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	209,178	163,428
Regulatory transition costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	608,000	770,000
Regulatory transition costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Regulatory transition costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Regulatory transition costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Regulatory transition costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	424,000	591,000
Regulatory transition costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	105,000	131,000
Regulatory transition costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	79,000	43,000
Customer receivables for future income taxes [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	508,000	328,000
Customer receivables for future income taxes [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	42,000	52,000
Customer receivables for future income taxes [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	1,000	2,000
Customer receivables for future income taxes [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	2,000	1,000
Customer receivables for future income taxes [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	29,000	30,000
Customer receivables for future income taxes [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	129,000	113,000
Customer receivables for future income taxes [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	145,000	130,000
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	(210,000)	(184,000)
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	(44,000)	(31,000)
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	(99,000)	(92,000)
Nuclear decommissioning, decontamination and spent fuel disposal costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	(67,000)	(61,000)
Asset removal costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	(240,000)	(237,000)
Asset removal costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	(34,000)	(24,000)
Asset removal costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	(60,000)	(47,000)
Asset removal costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	(23,000)	(19,000)
Asset removal costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	(147,000)	(147,000)
Asset removal costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Asset removal costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
PJM transmission costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	340,000	183,000
PJM transmission costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	(3,000)	0
PJM transmission costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	(3,000)	0
PJM transmission costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	(1,000)	0
PJM transmission costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
PJM transmission costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	181,000	131,000
PJM transmission costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	63,000	52,000
Deferred generation costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	382,000	386,000
Deferred generation costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	125,000	125,000
Deferred generation costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	224,000	226,000
Deferred generation costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	37,000	35,000
Deferred generation costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Deferred generation costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	(23,000)	0
Deferred generation costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	(11,000)	0
Distribution Costs [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	267,000	426,000
Distribution Costs [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	146,000	216,000
Distribution Costs [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	73,000	155,000
Distribution Costs [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	48,000	55,000
Distribution Costs [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Distribution Costs [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Distribution Costs [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	0	0
Regulatory Assets Other [Member]
Regulatory assets on the Balance Sheets
Regulatory Assets	375,000	158,000
Regulatory Assets Other [Member] | OE
Regulatory assets on the Balance Sheets
Regulatory Assets	87,000	34,000
Regulatory Assets Other [Member] | CEI
Regulatory assets on the Balance Sheets
Regulatory Assets	60,000	34,000
Regulatory Assets Other [Member] | TE
Regulatory assets on the Balance Sheets
Regulatory Assets	7,000	1,000
Regulatory Assets Other [Member] | JCP&L
Regulatory assets on the Balance Sheets
Regulatory Assets	146,000	71,000
Regulatory Assets Other [Member] | Met-Ed
Regulatory assets on the Balance Sheets
Regulatory Assets	36,000	13,000
Regulatory Assets Other [Member] | Penelec
Regulatory assets on the Balance Sheets
Regulatory Assets	$ 0	$ (1,000)