Fair Value Measurements (Details 5) (Recurring, USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Assets
Fair value, assets	$ 2,814		$ 2,649
Liabilities
Fair value, liabilities	(619)		(814)
Net assets (liabilities)	2,195	[1]	1,835	[1]
Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	(247)		(348)
FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	(23)		0
Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(349)	[2]	(466)	[2]
Corporate debt securities
Assets
Fair value, assets	1,544		597
Commodity Contracts | Derivative Assets
Assets
Fair value, assets	264		250
FTRs | Derivative Assets
Assets
Fair value, assets	1		0
Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	56	[2]	122	[2]
Equity Securities
Assets
Fair value, assets	259	[3]	338	[3]
Foreign Government Debt Securities [Member]
Assets
Fair value, assets	3		149
U.S. government debt securities
Assets
Fair value, assets	148		595
U.S. state debt securities
Assets
Fair value, assets	314		379
Other
Assets
Fair value, assets	225	[4]	219	[4]
Level 1
Assets
Fair value, assets	259		338
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	259	[1]	338	[1]
Level 1 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
Level 1 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
Level 1 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[2]	0	[2]
Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
Level 1 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Level 1 | FTRs | Derivative Assets
Assets
Fair value, assets	0		0
Level 1 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[2]	0	[2]
Level 1 | Equity Securities
Assets
Fair value, assets	259	[3]	338	[3]
Level 1 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
Level 1 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Level 2
Assets
Fair value, assets	2,498		2,189
Liabilities
Fair value, liabilities	(247)		(348)
Net assets (liabilities)	2,251	[1]	1,841	[1]
Level 2 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	(247)		(348)
Level 2 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
Level 2 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[2]	0	[2]
Level 2 | Corporate debt securities
Assets
Fair value, assets	1,544		597
Level 2 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	264		250
Level 2 | FTRs | Derivative Assets
Assets
Fair value, assets	0		0
Level 2 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[2]	0	[2]
Level 2 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Level 2 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	3		149
Level 2 | U.S. government debt securities
Assets
Fair value, assets	148		595
Level 2 | U.S. state debt securities
Assets
Fair value, assets	314		379
Level 2 | Other
Assets
Fair value, assets	225	[4]	219	[4]
Level 3
Assets
Fair value, assets	57		122
Liabilities
Fair value, liabilities	(372)		(466)
Net assets (liabilities)	(315)	[1]	(344)	[1]
Level 3 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
Level 3 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	(23)		0
Level 3 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(349)	[2]	(466)	[2]
Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
Level 3 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Level 3 | FTRs | Derivative Assets
Assets
Fair value, assets	1		0
Level 3 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	56	[2]	122	[2]
Level 3 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Level 3 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
Level 3 | Other
Assets
Fair value, assets	0	[4]	0	[4]
FES
Assets
Fair value, assets	1,530		1,378
Liabilities
Fair value, liabilities	(241)		(348)
Net assets (liabilities)	1,289	[5]	1,030	[5]
FES | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	(234)		(348)
FES | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	(7)		0
FES | Corporate debt securities
Assets
Fair value, assets	1,010		528
FES | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	248		241
FES | FTRs | Derivative Assets
Assets
Fair value, assets	1		0
FES | Equity Securities
Assets
Fair value, assets	124	[6]	0	[6]
FES | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	3		147
FES | U.S. government debt securities
Assets
Fair value, assets	7		308
FES | U.S. state debt securities
Assets
Fair value, assets	5		6
FES | Other
Assets
Fair value, assets	132	[7]	148	[7]
FES | Level 1
Assets
Fair value, assets	124		0
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	124	[5]	0	[5]
FES | Level 1 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
FES | Level 1 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
FES | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
FES | Level 1 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
FES | Level 1 | FTRs | Derivative Assets
Assets
Fair value, assets	0		0
FES | Level 1 | Equity Securities
Assets
Fair value, assets	124	[6]	0	[6]
FES | Level 1 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
FES | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
FES | Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
FES | Level 1 | Other
Assets
Fair value, assets	0	[7]	0	[7]
FES | Level 2
Assets
Fair value, assets	1,405		1,378
Liabilities
Fair value, liabilities	(234)		(348)
Net assets (liabilities)	1,171	[5]	1,030	[5]
FES | Level 2 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	(234)		(348)
FES | Level 2 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
FES | Level 2 | Corporate debt securities
Assets
Fair value, assets	1,010		528
FES | Level 2 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	248		241
FES | Level 2 | FTRs | Derivative Assets
Assets
Fair value, assets	0		0
FES | Level 2 | Equity Securities
Assets
Fair value, assets	0	[6]	0	[6]
FES | Level 2 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	3		147
FES | Level 2 | U.S. government debt securities
Assets
Fair value, assets	7		308
FES | Level 2 | U.S. state debt securities
Assets
Fair value, assets	5		6
FES | Level 2 | Other
Assets
Fair value, assets	132	[7]	148	[7]
FES | Level 3
Assets
Fair value, assets	1		0
Liabilities
Fair value, liabilities	(7)		0
Net assets (liabilities)	(6)	[5]	0	[5]
FES | Level 3 | Commodity Contracts | Derivative Liabilities
Liabilities
Fair value, liabilities	0		0
FES | Level 3 | FTRs | Derivative Liabilities
Liabilities
Fair value, liabilities	(7)		0
FES | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
FES | Level 3 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
FES | Level 3 | FTRs | Derivative Assets
Assets
Fair value, assets	1		0
FES | Level 3 | Equity Securities
Assets
Fair value, assets	0	[6]	0	[6]
FES | Level 3 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
FES | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
FES | Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
FES | Level 3 | Other
Assets
Fair value, assets	0	[7]	0	[7]
TE
Assets
Fair value, assets	83		76
TE | Corporate debt securities
Assets
Fair value, assets	53		7
TE | Equity Securities
Assets
Fair value, assets	27	[3]	0	[3]
TE | U.S. government debt securities
Assets
Fair value, assets	0		33
TE | U.S. state debt securities
Assets
Fair value, assets	0		1
TE | Other
Assets
Fair value, assets	3	[4]	35	[4]
TE | Level 1
Assets
Fair value, assets	27		0
TE | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
TE | Level 1 | Equity Securities
Assets
Fair value, assets	27	[3]	0	[3]
TE | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
TE | Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
TE | Level 1 | Other
Assets
Fair value, assets	0	[4]	0	[4]
TE | Level 2
Assets
Fair value, assets	56		76
TE | Level 2 | Corporate debt securities
Assets
Fair value, assets	53		7
TE | Level 2 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
TE | Level 2 | U.S. government debt securities
Assets
Fair value, assets	0		33
TE | Level 2 | U.S. state debt securities
Assets
Fair value, assets	0		1
TE | Level 2 | Other
Assets
Fair value, assets	3	[4]	35	[4]
TE | Level 3
Assets
Fair value, assets	0		0
TE | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
TE | Level 3 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
TE | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
TE | Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
TE | Level 3 | Other
Assets
Fair value, assets	0	[4]	0	[4]
JCP&L
Assets
Fair value, assets	414		400
Liabilities
Fair value, liabilities	(147)		(233)
Net assets (liabilities)	267	[4]	167	[4]
JCP&L | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(147)	[8]	(233)	[8]
JCP&L | Corporate debt securities
Assets
Fair value, assets	144		23
JCP&L | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		2
JCP&L | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	4	[8]	6	[8]
JCP&L | Equity Securities
Assets
Fair value, assets	30	[3]	96	[3]
JCP&L | U.S. government debt securities
Assets
Fair value, assets	2		33
JCP&L | U.S. state debt securities
Assets
Fair value, assets	219		236
JCP&L | Other
Assets
Fair value, assets	15		4
JCP&L | Level 1
Assets
Fair value, assets	30		96
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	30	[4]	96	[4]
JCP&L | Level 1 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
JCP&L | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 1 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
JCP&L | Level 1 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
JCP&L | Level 1 | Equity Securities
Assets
Fair value, assets	30	[3]	96	[3]
JCP&L | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 1 | Other
Assets
Fair value, assets	0		0
JCP&L | Level 2
Assets
Fair value, assets	380		298
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	380	[4]	298	[4]
JCP&L | Level 2 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
JCP&L | Level 2 | Corporate debt securities
Assets
Fair value, assets	144		23
JCP&L | Level 2 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		2
JCP&L | Level 2 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
JCP&L | Level 2 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
JCP&L | Level 2 | U.S. government debt securities
Assets
Fair value, assets	2		33
JCP&L | Level 2 | U.S. state debt securities
Assets
Fair value, assets	219		236
JCP&L | Level 2 | Other
Assets
Fair value, assets	15		4
JCP&L | Level 3
Assets
Fair value, assets	4		6
Liabilities
Fair value, liabilities	(147)		(233)
Net assets (liabilities)	(143)	[4]	(227)	[4]
JCP&L | Level 3 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(147)	[8]	(233)	[8]
JCP&L | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 3 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
JCP&L | Level 3 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	4	[8]	6	[8]
JCP&L | Level 3 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
JCP&L | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
JCP&L | Level 3 | Other
Assets
Fair value, assets	0		0
OE
Assets
Fair value, assets	137	[9]	126	[9]
OE | Corporate debt securities
Assets
Fair value, assets	3		0
OE | U.S. government debt securities
Assets
Fair value, assets	132		124
OE | Other
Assets
Fair value, assets	2	[4]	2	[4]
OE | Level 1
Assets
Fair value, assets	0	[9]	0	[9]
OE | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
OE | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
OE | Level 1 | Other
Assets
Fair value, assets	0	[4]	0	[4]
OE | Level 2
Assets
Fair value, assets	137	[9]	126	[9]
OE | Level 2 | Corporate debt securities
Assets
Fair value, assets	3		0
OE | Level 2 | U.S. government debt securities
Assets
Fair value, assets	132		124
OE | Level 2 | Other
Assets
Fair value, assets	2	[4]	2	[4]
OE | Level 3
Assets
Fair value, assets	0	[9]	0	[9]
OE | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
OE | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
OE | Level 3 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Met-Ed
Assets
Fair value, assets	357		414
Liabilities
Fair value, liabilities	(79)		(116)
Net assets (liabilities)	278	[10]	298	[10]
Met-Ed | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(79)	[8]	(116)	[8]
Met-Ed | Corporate debt securities
Assets
Fair value, assets	229		32
Met-Ed | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		5
Met-Ed | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	49	[8]	112	[8]
Met-Ed | Equity Securities
Assets
Fair value, assets	51	[3]	160	[3]
Met-Ed | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		1
Met-Ed | U.S. government debt securities
Assets
Fair value, assets	5		88
Met-Ed | U.S. state debt securities
Assets
Fair value, assets	0		2
Met-Ed | Other
Assets
Fair value, assets	23	[4]	14	[4]
Met-Ed | Level 1
Assets
Fair value, assets	51		160
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	51	[10]	160	[10]
Met-Ed | Level 1 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
Met-Ed | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 1 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Met-Ed | Level 1 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
Met-Ed | Level 1 | Equity Securities
Assets
Fair value, assets	51	[3]	160	[3]
Met-Ed | Level 1 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
Met-Ed | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 1 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Met-Ed | Level 2
Assets
Fair value, assets	257		142
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	257	[10]	142	[10]
Met-Ed | Level 2 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
Met-Ed | Level 2 | Corporate debt securities
Assets
Fair value, assets	229		32
Met-Ed | Level 2 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		5
Met-Ed | Level 2 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
Met-Ed | Level 2 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Met-Ed | Level 2 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		1
Met-Ed | Level 2 | U.S. government debt securities
Assets
Fair value, assets	5		88
Met-Ed | Level 2 | U.S. state debt securities
Assets
Fair value, assets	0		2
Met-Ed | Level 2 | Other
Assets
Fair value, assets	23	[4]	14	[4]
Met-Ed | Level 3
Assets
Fair value, assets	49		112
Liabilities
Fair value, liabilities	(79)		(116)
Net assets (liabilities)	(30)	[10]	(4)	[10]
Met-Ed | Level 3 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(79)	[8]	(116)	[8]
Met-Ed | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 3 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Met-Ed | Level 3 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	49	[8]	112	[8]
Met-Ed | Level 3 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Met-Ed | Level 3 | Foreign Government Debt Securities [Member]
Assets
Fair value, assets	0		0
Met-Ed | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
Met-Ed | Level 3 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Penelec | Level 1
Assets
Fair value, assets	26		81
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	26	[11]	81	[11]
Penelec | Level 1 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
Penelec | Level 1 | Corporate debt securities
Assets
Fair value, assets	0		0
Penelec | Level 1 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Penelec | Level 1 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
Penelec | Level 1 | Equity Securities
Assets
Fair value, assets	26	[3]	81	[3]
Penelec | Level 1 | U.S. government debt securities
Assets
Fair value, assets	0		0
Penelec | Level 1 | U.S. state debt securities
Assets
Fair value, assets	0		0
Penelec | Level 1 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Penelec | Level 2
Assets
Fair value, assets	235		157
Liabilities
Fair value, liabilities	0		0
Net assets (liabilities)	235	[11]	157	[11]
Penelec | Level 2 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	0	[8]	0	[8]
Penelec | Level 2 | Corporate debt securities
Assets
Fair value, assets	104		8
Penelec | Level 2 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		2
Penelec | Level 2 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	0	[8]	0	[8]
Penelec | Level 2 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Penelec | Level 2 | U.S. government debt securities
Assets
Fair value, assets	2		9
Penelec | Level 2 | U.S. state debt securities
Assets
Fair value, assets	90		133
Penelec | Level 2 | Other
Assets
Fair value, assets	39	[4]	5	[4]
Penelec | Level 3
Assets
Fair value, assets	3		4
Liabilities
Fair value, liabilities	(123)		(117)
Net assets (liabilities)	(120)	[11]	(113)	[11]
Penelec | Level 3 | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(123)	[8]	(117)	[8]
Penelec | Level 3 | Corporate debt securities
Assets
Fair value, assets	0		0
Penelec | Level 3 | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		0
Penelec | Level 3 | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	3	[8]	4	[8]
Penelec | Level 3 | Equity Securities
Assets
Fair value, assets	0	[3]	0	[3]
Penelec | Level 3 | U.S. government debt securities
Assets
Fair value, assets	0		0
Penelec | Level 3 | U.S. state debt securities
Assets
Fair value, assets	0		0
Penelec | Level 3 | Other
Assets
Fair value, assets	0	[4]	0	[4]
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Fair value, assets	264		242
Liabilities
Fair value, liabilities	(123)		(117)
Net assets (liabilities)	141	[11]	125	[11]
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Non Utility Generation Contract | Derivative Liabilities
Liabilities
Fair value, liabilities	(123)	[8]	(117)	[8]
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate debt securities
Assets
Fair value, assets	104		8
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Commodity Contracts | Derivative Assets
Assets
Fair value, assets	0		2
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Non Utility Generation Contract | Derivative Assets
Assets
Fair value, assets	3	[8]	4	[8]
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity Securities
Assets
Fair value, assets	26	[3]	81	[3]
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government debt securities
Assets
Fair value, assets	2		9
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. state debt securities
Assets
Fair value, assets	90		133
Penelec | Estimate of Fair Value, Fair Value Disclosure [Member] | Other
Assets
Fair value, assets	$ 39	[4]	$ 5	[4]

[1] Excludes $(52) million and $(7) million as of December 31, 2011 and 2010, respectively, of receivables, payables, taxes and accrued income associated with financial instruments reflected within the fair value table

[2] NUG contracts are generally subject to regulatory accounting and do not impact earnings.

[3] NDT funds hold equity portfolios whose performance is benchmarked against the Alerian MLP Index.

[4] Primarily consists of short-term cash investments.

[5] Excludes $(58) million and $7 million as of December 31, 2011 and 2010, respectively, of receivables, payables, taxes and accrued income associated with the financial instruments reflected within the fair value table.

[6] NDT funds hold equity portfolios whose performance of which is benchmarked against the Alerian MLP Index

[7] Primarily consists of short-term cash investments

[8] NUG contracts are subject to regulatory accounting and do not impact earnings.

[9] Excludes $1 million as of December 31, 2011 and 2010 of receivables, payables, taxes and accrued income associated with the financial instruments reflected within the fair value table.

[10] Excludes $2 million and $(9) million as of December 31, 2011 and 2010, respectively, of receivables, payables, taxes and accrued income associated with the financial instruments reflected within the fair value table.

[11] Excludes $1 million and $(3) million as of December 31, 2011 and 2010, respectively, of receivables, payables, taxes and accrued income associated with the financial instruments reflected within the fair value table.