Supplemental Guarantor Information (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CURRENT ASSETS:
Cash and cash equivalents	$ 172	$ 202	$ 1,019	$ 874
Receivables-
Customers	1,614	1,525
Other	315	269
Materials and supplies, at average cost	861	811
Derivatives	192	235
Prepayments and other	176	122
Total current assets	3,768	3,355
PROPERTY, PLANT AND EQUIPMENT:
In service	43,210	40,122
Less - Accumulated provision for depreciation	12,600	11,839
Property, plant and equipment in service net of accumulated provision for depreciation	30,610	28,283
Construction work in progress	2,293	2,054
Total net property, plant and equipment	32,903	30,337
INVESTMENTS:
Nuclear plant decommissioning trusts	2,204	2,112
Other	936	1,008
Total other property and investments	3,194	3,522
DEFERRED CHARGES AND OTHER ASSETS:
Customer intangibles	702
Goodwill	6,447	6,441	5,575
Other	1,719	1,641
Total deferred charges and other assets	10,541	10,112
Total assets	50,406	47,326	35,531
CURRENT LIABILITIES:
Currently payable long-term debt	1,999	1,621
Short-term borrowings-
Affiliated companies	1,969	0
Accounts payable-
Accrued taxes	543	558
Derivatives	126	218
Other	1,038	900
Total current liabilities	7,605	4,855
CAPITALIZATION:
Total equity	13,084	13,280
Long-term debt and other long-term obligations	15,179	15,716
Total capitalization	28,272	29,015
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	892	925
Accumulated deferred income taxes	6,616	5,670
Asset retirement obligations	1,599	1,497
Retirement benefits	3,080	2,823
Other	1,836	2,072
Total noncurrent liabilities	14,529	13,456
Total liabilities and capitalization	50,406	47,326
FES Corp
CURRENT ASSETS:
Cash and cash equivalents	0	0	0	0
Receivables-
Customers	483	424
Affiliated companies	232	476
Other	56	28
Notes receivable from affiliated companies	366	155
Materials and supplies, at average cost	66	60
Derivatives	190	219
Prepayments and other	6	11
Total current assets	1,399	1,373
PROPERTY, PLANT AND EQUIPMENT:
In service	91	84
Less - Accumulated provision for depreciation	32	28
Property, plant and equipment in service net of accumulated provision for depreciation	59	56
Construction work in progress	34	29
Total net property, plant and equipment	93	85
INVESTMENTS:
Nuclear plant decommissioning trusts	0	0
Investment in affiliated companies	4,972	5,700
Other	0	0
Total other property and investments	4,972	5,700
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	0	10
Customer intangibles	110	123
Goodwill	24	24
Property taxes	0	0
Unamortized sale and leaseback costs	0	0
Derivatives	99	79
Other	160	89
Total deferred charges and other assets	393	325
Total assets	6,857	7,483
CURRENT LIABILITIES:
Currently payable long-term debt	1	1
Accounts payable-
Affiliated companies	748	777
Other	63	99
Accrued taxes	126	84
Derivatives	124	189
Other	71	62
Total current liabilities	1,491	2,277
CAPITALIZATION:
Total equity	3,763	3,577
Long-term debt and other long-term obligations	1,482	1,483
Total capitalization	5,245	5,060
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0	0
Accumulated deferred income taxes	28	12
Asset retirement obligations	0	0
Retirement benefits	26	56
Lease market valuation liability		0
Other	67	78
Total noncurrent liabilities	121	146
Total liabilities and capitalization	6,857	7,483
FGCO
CURRENT ASSETS:
Cash and cash equivalents	3	7	9	0
Receivables-
Customers	0	0
Affiliated companies	417	643
Other	19	20
Notes receivable from affiliated companies	7	1,346
Materials and supplies, at average cost	231	232
Derivatives	0	0
Prepayments and other	39	26
Total current assets	716	2,274
PROPERTY, PLANT AND EQUIPMENT:
In service	5,899	5,573
Less - Accumulated provision for depreciation	1,915	1,813
Property, plant and equipment in service net of accumulated provision for depreciation	3,984	3,760
Construction work in progress	230	195
Total net property, plant and equipment	4,214	3,955
INVESTMENTS:
Nuclear plant decommissioning trusts	0	0
Investment in affiliated companies	0	0
Other	12	7
Total other property and investments	12	7
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	313	307
Customer intangibles	0	0
Goodwill	0	0
Property taxes	14	20
Unamortized sale and leaseback costs	0	5
Derivatives	0	0
Other	194	99
Total deferred charges and other assets	521	431
Total assets	5,463	6,667
CURRENT LIABILITIES:
Currently payable long-term debt	586	411
Accounts payable-
Affiliated companies	143	228
Other	96	121
Accrued taxes	25	42
Derivatives	0	0
Other	152	141
Total current liabilities	1,348	1,032
CAPITALIZATION:
Total equity	1,787	3,097
Long-term debt and other long-term obligations	2,009	1,905
Total capitalization	3,796	5,002
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0	0
Accumulated deferred income taxes	0	0
Asset retirement obligations	29	28
Retirement benefits	215	300
Lease market valuation liability		171
Other	75	134
Total noncurrent liabilities	319	633
Total liabilities and capitalization	5,463	6,667
Nuclear Generation Corp
CURRENT ASSETS:
Cash and cash equivalents	0	0	0	0
Receivables-
Customers	0	0
Affiliated companies	478	262
Other	16	13
Notes receivable from affiliated companies	607	69
Materials and supplies, at average cost	208	200
Derivatives	0	0
Prepayments and other	10	1
Total current assets	1,319	545
PROPERTY, PLANT AND EQUIPMENT:
In service	6,391	5,711
Less - Accumulated provision for depreciation	2,646	2,449
Property, plant and equipment in service net of accumulated provision for depreciation	3,745	3,262
Construction work in progress	877	790
Total net property, plant and equipment	4,622	4,052
INVESTMENTS:
Nuclear plant decommissioning trusts	1,283	1,223
Investment in affiliated companies	0	0
Other	0	0
Total other property and investments	1,283	1,223
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	0	0
Customer intangibles	0	0
Goodwill	0	0
Property taxes	22	23
Unamortized sale and leaseback costs	0	0
Derivatives	0	0
Other	5	3
Total deferred charges and other assets	27	26
Total assets	7,251	5,846
CURRENT LIABILITIES:
Currently payable long-term debt	537	513
Accounts payable-
Affiliated companies	583	211
Other	0	0
Accrued taxes	20	110
Derivatives	0	0
Other	15	16
Total current liabilities	1,155	882
CAPITALIZATION:
Total equity	3,165	2,587
Long-term debt and other long-term obligations	834	641
Total capitalization	3,999	3,228
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0	0
Accumulated deferred income taxes	714	510
Asset retirement obligations	936	876
Retirement benefits	0	0
Lease market valuation liability		0
Other	447	350
Total noncurrent liabilities	2,097	1,736
Total liabilities and capitalization	7,251	5,846
Eliminations
CURRENT ASSETS:
Cash and cash equivalents	0	0	0	0
Receivables-
Customers	0	0
Affiliated companies	(748)	(781)
Other	0	0
Notes receivable from affiliated companies	(704)	(1,187)
Materials and supplies, at average cost	0	0
Derivatives	0	0
Prepayments and other	0	0
Total current assets	(1,452)	(1,968)
PROPERTY, PLANT AND EQUIPMENT:
In service	(384)	(385)
Less - Accumulated provision for depreciation	(185)	(180)
Property, plant and equipment in service net of accumulated provision for depreciation	(199)	(205)
Construction work in progress	0	0
Total net property, plant and equipment	(199)	(205)
INVESTMENTS:
Nuclear plant decommissioning trusts	0	0
Investment in affiliated companies	(4,972)	(5,700)
Other	0	0
Total other property and investments	(4,972)	(5,700)
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	(313)	(317)
Customer intangibles	0	0
Goodwill	0	0
Property taxes	0	0
Unamortized sale and leaseback costs	119	75
Derivatives	0	0
Other	(106)	(62)
Total deferred charges and other assets	(300)	(304)
Total assets	(6,923)	(8,177)
CURRENT LIABILITIES:
Currently payable long-term debt	(22)	(20)
Accounts payable-
Affiliated companies	(748)	(780)
Other	0	0
Accrued taxes	0	(9)
Derivatives	0	0
Other	46	42
Total current liabilities	(1,428)	(1,953)
CAPITALIZATION:
Total equity	(4,952)	(5,684)
Long-term debt and other long-term obligations	(1,207)	(1,230)
Total capitalization	(6,159)	(6,914)
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	892	925
Accumulated deferred income taxes	(227)	(236)
Asset retirement obligations	0	0
Retirement benefits	0	0
Lease market valuation liability		0
Other	(1)	1
Total noncurrent liabilities	664	690
Total liabilities and capitalization	(6,923)	(8,177)
FES
CURRENT ASSETS:
Cash and cash equivalents	3	7	9	0
Receivables-
Customers	483	424
Affiliated companies	379	600
Other	91	61
Notes receivable from affiliated companies	276	383
Materials and supplies, at average cost	505	492
Derivatives	190	219
Prepayments and other	55	38
Total current assets	1,982	2,224
PROPERTY, PLANT AND EQUIPMENT:
In service	11,997	10,983
Less - Accumulated provision for depreciation	4,408	4,110
Property, plant and equipment in service net of accumulated provision for depreciation	7,589	6,873
Construction work in progress	1,141	1,014
Total net property, plant and equipment	8,730	7,887
INVESTMENTS:
Nuclear plant decommissioning trusts	1,283	1,223
Investment in affiliated companies	0	0
Other	12	7
Total other property and investments	1,295	1,230
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	0	0
Customer intangibles	110	123
Goodwill	24	24
Property taxes	36	43
Unamortized sale and leaseback costs	119	80
Derivatives	99	79
Other	253	129
Total deferred charges and other assets	641	478
Total assets	12,648	11,819
CURRENT LIABILITIES:
Currently payable long-term debt	1,102	905
Accounts payable-
Affiliated companies	726	436
Other	159	220
Accrued taxes	171	227
Derivatives	124	189
Other	284	261
Total current liabilities	2,566	2,238
CAPITALIZATION:
Total equity	3,763	3,577
Long-term debt and other long-term obligations	3,118	2,799
Total capitalization	6,881	6,376
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	892	925
Accumulated deferred income taxes	515	286
Asset retirement obligations	965	904
Retirement benefits	241	356
Lease market valuation liability	0	171
Other	588	563
Total noncurrent liabilities	3,201	3,205
Total liabilities and capitalization	12,648	11,819
Affiliates | FES Corp
Short-term borrowings-
Affiliated companies	358	1,065
Affiliates | FGCO
Short-term borrowings-
Affiliated companies	346	89
Affiliates | Nuclear Generation Corp
Short-term borrowings-
Affiliated companies	0	32
Affiliates | Eliminations
Short-term borrowings-
Affiliated companies	(704)	(1,186)
Affiliates | FES
Short-term borrowings-
Affiliated companies	$ 0	$ 0