Capitalization (Details 1) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Schedule of Capitalization [Line Items]
Secured Debt	$ 2,775,000,000	$ 2,784,000,000
Unsecured Debt	11,743,000,000	10,121,000,000
Capital Lease Obligations	108,000,000	54,000,000
Debt Instrument, Unamortized Discount	64,000,000	83,000,000
Long-term Debt, Current Maturities	(1,621,000,000)	(1,486,000,000)
Long-term Debt and Capital Lease Obligations	15,716,000,000	12,579,000,000
FES
Schedule of Capitalization [Line Items]
Secured Debt	949,000,000	1,272,000,000
Unsecured Debt	2,726,000,000	3,007,000,000
Capital Lease Obligations	31,000,000	36,000,000
Debt Instrument, Unamortized Discount	(2,000,000)	(2,000,000)
Long-term Debt, Current Maturities	(905,000,000)	(1,132,000,000)
Long-term Debt and Capital Lease Obligations	2,799,000,000	3,181,000,000
OE
Schedule of Capitalization [Line Items]
Capital Lease Obligations	11,000,000	7,000,000
Debt Instrument, Unamortized Discount	(11,000,000)	(12,000,000)
Long-term Debt, Current Maturities	(2,000,000)	(1,000,000)
Long-term Debt and Capital Lease Obligations	1,155,000,000	1,152,000,000
CEI
Schedule of Capitalization [Line Items]
Capital Lease Obligations	8,000,000	3,000,000
Debt Instrument, Unamortized Discount	(3,000,000)	(3,000,000)
Long-term Debt, Current Maturities	(1,000,000)	0
Long-term Debt and Capital Lease Obligations	1,834,890,000	1,852,530,000
TE
Schedule of Capitalization [Line Items]
Capital Lease Obligations	1,000,000	3,000,000
Debt Instrument, Unamortized Discount	(2,000,000)	(3,000,000)
Long-term Debt and Capital Lease Obligations	598,869,000	600,493,000
JCP&L
Schedule of Capitalization [Line Items]
Debt Instrument, Unamortized Discount	(7,000,000)	(8,000,000)
Long-term Debt, Current Maturities	(34,000,000)	(32,000,000)
Long-term Debt and Capital Lease Obligations	1,736,000,000	1,770,000,000
Met-Ed
Schedule of Capitalization [Line Items]
Unsecured Debt	729,000,000	729,000,000
Capital Lease Obligations	4,000,000	5,000,000
Long-term Debt, Current Maturities	(29,000,000)	(29,000,000)
Long-term Debt and Capital Lease Obligations	703,525,000	718,860,000
Penelec
Schedule of Capitalization [Line Items]
Unsecured Debt	1,120,000,000	1,120,000,000
Capital Lease Obligations	4,000,000	0
Debt Instrument, Unamortized Discount	(2,000,000)	(3,000,000)
Long-term Debt, Current Maturities	(46,000,000)	(45,000,000)
Long-term Debt and Capital Lease Obligations	1,075,781,000	1,072,262,000
FMB [Member]
Schedule of Capitalization [Line Items]
Other Long-term Debt	2,487,000,000	1,023,000,000
FMB [Member] | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.125%
FMB [Member] | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	9.74%
FMB [Member] | OE
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.25%
Other Long-term Debt	407,000,000	408,000,000
FMB [Member] | CEI
Schedule of Capitalization [Line Items]
Other Long-term Debt	600,000,000	600,000,000
FMB [Member] | CEI | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.50%
FMB [Member] | CEI | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.875%
FMB [Member] | Met-Ed
Schedule of Capitalization [Line Items]
Other Long-term Debt	0	14,000,000
Secured Debt, Fixed Rate [Member]
Schedule of Capitalization [Line Items]
Secured Debt	2,725,000,000	2,727,000,000
Secured Debt, Fixed Rate [Member] | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Secured Debt, Fixed Rate [Member] | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.88%
Secured Debt, Fixed Rate [Member] | FES
Schedule of Capitalization [Line Items]
Secured Debt	899,000,000	838,000,000
Secured Debt, Fixed Rate [Member] | FES | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Secured Debt, Fixed Rate [Member] | FES | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.25%
Secured Debt, Fixed Rate [Member] | CEI
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.88%
Secured Debt	300,000,000	300,000,000
Secured Debt, Fixed Rate [Member] | TE
Schedule of Capitalization [Line Items]
Secured Debt	600,000,000	600,000,000
Secured Debt, Fixed Rate [Member] | TE | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.15%
Secured Debt, Fixed Rate [Member] | TE | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.25%
Secured Debt, Fixed Rate [Member] | JCP&L
Schedule of Capitalization [Line Items]
Secured Debt	277,000,000	310,000,000
Secured Debt, Fixed Rate [Member] | JCP&L | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.25%
Secured Debt, Fixed Rate [Member] | JCP&L | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.16%
Secured Debt, Variable Rate [Member]
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.90%
Secured Debt	50,000,000	57,000,000
Secured Debt, Variable Rate [Member] | FES
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.90%
Secured Debt	50,000,000	434,000,000
Unsecured Debt, Fixed Rate [Member]
Schedule of Capitalization [Line Items]
Unsecured Debt	10,961,000,000	9,351,000,000
Unsecured Debt, Fixed Rate [Member] | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.225%
Unsecured Debt, Fixed Rate [Member] | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.25%
Unsecured Debt, Fixed Rate [Member] | FES
Schedule of Capitalization [Line Items]
Unsecured Debt	2,218,000,000	2,562,000,000
Unsecured Debt, Fixed Rate [Member] | FES | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.25%
Unsecured Debt, Fixed Rate [Member] | FES | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.80%
Unsecured Debt, Fixed Rate [Member] | OE
Schedule of Capitalization [Line Items]
Unsecured Debt	750,000,000	750,000,000
Unsecured Debt, Fixed Rate [Member] | OE | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.45%
Unsecured Debt, Fixed Rate [Member] | OE | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Unsecured Debt, Fixed Rate [Member] | CEI
Schedule of Capitalization [Line Items]
Unsecured Debt	850,000,000	850,000,000
Unsecured Debt, Fixed Rate [Member] | CEI | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.65%
Unsecured Debt, Fixed Rate [Member] | CEI | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.95%
Unsecured Debt, Fixed Rate [Member] | JCP&L
Schedule of Capitalization [Line Items]
Unsecured Debt	1,500,000,000	1,500,000,000
Unsecured Debt, Fixed Rate [Member] | JCP&L | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.80%
Unsecured Debt, Fixed Rate [Member] | JCP&L | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.35%
Unsecured Debt, Fixed Rate [Member] | Met-Ed
Schedule of Capitalization [Line Items]
Unsecured Debt	700,000,000	700,000,000
Unsecured Debt, Fixed Rate [Member] | Met-Ed | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.875%
Unsecured Debt, Fixed Rate [Member] | Met-Ed | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.70%
Unsecured Debt, Fixed Rate [Member] | Penelec
Schedule of Capitalization [Line Items]
Unsecured Debt	1,075,000,000	1,100,000,000
Unsecured Debt, Fixed Rate [Member] | Penelec | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.125%
Unsecured Debt, Fixed Rate [Member] | Penelec | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
Unsecured Debt, Variable Rate [Member]
Schedule of Capitalization [Line Items]
Unsecured Debt	782,000,000	770,000,000
Unsecured Debt, Variable Rate [Member] | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.03%
Unsecured Debt, Variable Rate [Member] | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.918%
Unsecured Debt, Variable Rate [Member] | FES
Schedule of Capitalization [Line Items]
Unsecured Debt	508,000,000	445,000,000
Unsecured Debt, Variable Rate [Member] | FES | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.40%
Unsecured Debt, Variable Rate [Member] | FES | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.90%
Unsecured Debt, Variable Rate [Member] | Met-Ed
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.90%
Unsecured Debt	29,000,000	29,000,000
Unsecured Debt, Variable Rate [Member] | Penelec
Schedule of Capitalization [Line Items]
Unsecured Debt	45,000,000	20,000,000
Unsecured Debt, Variable Rate [Member] | Penelec | Minimum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.003%
Unsecured Debt, Variable Rate [Member] | Penelec | Maximum
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.09%
Unamortized Merger Fair Value Adjustments [Member]
Schedule of Capitalization [Line Items]
Debt Instrument, Fair Value Disclosure	160,000,000	0
Unsecured Debt, Due to Affiliates [Member] | CEI
Schedule of Capitalization [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.663%
Unsecured Debt	$ 81,000,000	$ 103,000,000