Supplemental Guarantor Information (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Feb. 12, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 85		$ 218	$ 172	$ 202
Receivables-
Customers	1,554		1,720
Other Receivables	225		198
Materials and supplies, at average cost	817		752
Derivatives	159		166
Collateral	230		155
Prepayments and other	160		212
Total current assets	3,876		4,013
PROPERTY, PLANT AND EQUIPMENT:
In service	47,484		44,228
Less - Accumulated provision for depreciation	14,150		13,280
Property, plant and equipment in service net of accumulated provision for depreciation	33,334		30,948
Construction work in progress	2,449		2,304
Total net property, plant and equipment	35,783		33,252
INVESTMENTS:
Nuclear plant decommissioning trusts	2,341		2,201
Other	881		903
Total other property and investments	3,222		3,104
ASSETS HELD FOR SALE (Note 19)	0	235	235
DEFERRED CHARGES AND OTHER ASSETS:
Customer intangibles	496
Goodwill	6,418		6,418	6,447
Other	1,456		1,548
Total deferred charges and other assets	9,285		9,820
Total assets	52,166		50,424	50,494
CURRENT LIABILITIES:
Currently payable long-term debt	804		1,415
Short-term borrowings	1,799		3,404
Accounts payable-
Accrued taxes	490		485
Derivatives	167		111
Other	693		621
Total current liabilities	5,561		7,637
CAPITALIZATION:
Total equity	12,420		12,692
Long-term debt and other long-term obligations	19,176		15,831
Total capitalization	31,598		28,526
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	824		858
Accumulated deferred income taxes	7,057		6,968
Asset retirement obligations	1,387		1,678
Retirement benefits	3,932		2,689
Other	1,590		1,778
Total noncurrent liabilities	15,007		14,261
Total liabilities and capitalization	52,166		50,424
FES
CURRENT ASSETS:
Cash and cash equivalents	0		0	0	0
Receivables-
Customers	415		539
Affiliated companies	484		938
Other Receivables	66		52
Notes receivable from affiliated companies	339		203
Materials and supplies, at average cost	67		76
Derivatives	147		165
Collateral	229		136
Prepayments and other	56		52
Total current assets	1,803		2,161
PROPERTY, PLANT AND EQUIPMENT:
In service	133		104
Less - Accumulated provision for depreciation	36		28
Property, plant and equipment in service net of accumulated provision for depreciation	97		76
Construction work in progress	3		23
Total net property, plant and equipment	100		99
INVESTMENTS:
Nuclear plant decommissioning trusts	0		0
Investment in affiliated companies	6,607		5,801
Other	0		0
Total other property and investments	6,607		5,801
ASSETS HELD FOR SALE (Note 19)			0
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	276		0
Customer intangibles	78		95
Goodwill	23		23
Property taxes	0		0
Unamortized sale and leaseback costs	0		0
Derivatives	52		53
Other	34		81
Total deferred charges and other assets	463		252
Total assets	8,973		8,313
CURRENT LIABILITIES:
Currently payable long-term debt	18		1
Short-term borrowings	90		0
Accounts payable-
Affiliated companies	1,068		741
Other	46		94
Accrued taxes	2		204
Derivatives	166		110
Other	72		70
Total current liabilities	2,597		2,197
CAPITALIZATION:
Total equity	5,585		5,312
Long-term debt and other long-term obligations	695		712
Total capitalization	6,280		6,024
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0		0
Accumulated deferred income taxes	13		32
Asset retirement obligations	0		0
Retirement benefits	36		22
Derivatives	14		14
Other	33		24
Total noncurrent liabilities	96		92
Total liabilities and capitalization	8,973		8,313
FES | Affiliates
CURRENT LIABILITIES:
Other Short-term Borrowings	1,135		977
FGCO
CURRENT ASSETS:
Cash and cash equivalents	2		2	3	7
Receivables-
Customers	0		0
Affiliated companies	487		787
Other Receivables	21		12
Notes receivable from affiliated companies	838		23
Materials and supplies, at average cost	202		159
Derivatives	0		0
Collateral	0		0
Prepayments and other	41		50
Total current assets	1,591		1,033
PROPERTY, PLANT AND EQUIPMENT:
In service	6,217		6,105
Less - Accumulated provision for depreciation	2,058		1,953
Property, plant and equipment in service net of accumulated provision for depreciation	4,159		4,152
Construction work in progress	206		148
Total net property, plant and equipment	4,365		4,300
INVESTMENTS:
Nuclear plant decommissioning trusts	0		0
Investment in affiliated companies	0		0
Other	10		11
Total other property and investments	10		11
ASSETS HELD FOR SALE (Note 19)			122
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	76		131
Customer intangibles	0		0
Goodwill	0		0
Property taxes	14		15
Unamortized sale and leaseback costs	0		0
Derivatives	0		0
Other	277		228
Total deferred charges and other assets	367		374
Total assets	6,333		5,840
CURRENT LIABILITIES:
Currently payable long-term debt	164		367
Short-term borrowings	9		4
Accounts payable-
Affiliated companies	197		400
Other	202		196
Accrued taxes	62		23
Derivatives	0		0
Other	56		63
Total current liabilities	1,011		1,265
CAPITALIZATION:
Total equity	2,561		2,283
Long-term debt and other long-term obligations	2,215		1,860
Total capitalization	4,776		4,143
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0		0
Accumulated deferred income taxes	0		0
Asset retirement obligations	189		187
Retirement benefits	288		163
Derivatives	0		0
Other	69		82
Total noncurrent liabilities	546		432
Total liabilities and capitalization	6,333		5,840
FGCO | Affiliates
CURRENT LIABILITIES:
Other Short-term Borrowings	321		212
Nuclear Generation Corp
CURRENT ASSETS:
Cash and cash equivalents	0		0	0	0
Receivables-
Customers	0		0
Affiliated companies	674		227
Other Receivables	20		17
Notes receivable from affiliated companies	272		683
Materials and supplies, at average cost	223		213
Derivatives	0		0
Collateral	0		0
Prepayments and other	0		7
Total current assets	1,189		1,147
PROPERTY, PLANT AND EQUIPMENT:
In service	7,628		6,645
Less - Accumulated provision for depreciation	3,305		2,962
Property, plant and equipment in service net of accumulated provision for depreciation	4,323		3,683
Construction work in progress	801		1,137
Total net property, plant and equipment	5,124		4,820
INVESTMENTS:
Nuclear plant decommissioning trusts	1,365		1,276
Investment in affiliated companies	0		0
Other	0		0
Total other property and investments	1,365		1,276
ASSETS HELD FOR SALE (Note 19)			0
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	0		0
Customer intangibles	0		0
Goodwill	0		0
Property taxes	27		26
Unamortized sale and leaseback costs	0		0
Derivatives	0		0
Other	7		18
Total deferred charges and other assets	34		44
Total assets	7,712		7,287
CURRENT LIABILITIES:
Currently payable long-term debt	348		547
Short-term borrowings	0		0
Accounts payable-
Affiliated companies	219		362
Other	0		0
Accrued taxes	161		23
Derivatives	0		0
Other	9		18
Total current liabilities	765		1,101
CAPITALIZATION:
Total equity	4,014		3,493
Long-term debt and other long-term obligations	859		742
Total capitalization	4,873		4,235
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	0		0
Accumulated deferred income taxes	678		736
Asset retirement obligations	652		828
Retirement benefits	0		0
Derivatives	0		0
Other	744		387
Total noncurrent liabilities	2,074		1,951
Total liabilities and capitalization	7,712		7,287
Nuclear Generation Corp | Affiliates
CURRENT LIABILITIES:
Other Short-term Borrowings	28		151
Eliminations
CURRENT ASSETS:
Cash and cash equivalents	0		0	0	0
Receivables-
Customers	0		0
Affiliated companies	(1,120)		(916)
Other Receivables	0		0
Notes receivable from affiliated companies	(1,449)		(909)
Materials and supplies, at average cost	0		0
Derivatives	0		0
Collateral	0		0
Prepayments and other	(2)		0
Total current assets	(2,571)		(1,825)
PROPERTY, PLANT AND EQUIPMENT:
In service	(382)		(382)
Less - Accumulated provision for depreciation	(191)		(188)
Property, plant and equipment in service net of accumulated provision for depreciation	(191)		(194)
Construction work in progress	0		0
Total net property, plant and equipment	(191)		(194)
INVESTMENTS:
Nuclear plant decommissioning trusts	0		0
Investment in affiliated companies	(6,607)		(5,801)
Other	0		0
Total other property and investments	(6,607)		(5,801)
ASSETS HELD FOR SALE (Note 19)			0
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	(352)		(131)
Customer intangibles	0		0
Goodwill	0		0
Property taxes	0		0
Unamortized sale and leaseback costs	217		168
Derivatives	0		0
Other	(204)		(155)
Total deferred charges and other assets	(339)		(118)
Total assets	(9,708)		(7,938)
CURRENT LIABILITIES:
Currently payable long-term debt	(24)		(23)
Short-term borrowings	0		0
Accounts payable-
Affiliated companies	(1,068)		(738)
Other	0		0
Accrued taxes	(123)		(184)
Derivatives	0		0
Other	47		46
Total current liabilities	(2,617)		(1,808)
CAPITALIZATION:
Total equity	(6,575)		(5,776)
Long-term debt and other long-term obligations	(1,161)		(1,184)
Total capitalization	(7,736)		(6,960)
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	824		858
Accumulated deferred income taxes	(180)		(27)
Asset retirement obligations	0		0
Retirement benefits	0		0
Derivatives	0		0
Other	1		(1)
Total noncurrent liabilities	645		830
Total liabilities and capitalization	(9,708)		(7,938)
Eliminations | Affiliates
CURRENT LIABILITIES:
Other Short-term Borrowings	(1,449)		(909)
FES
CURRENT ASSETS:
Cash and cash equivalents	2		2	3	7
Receivables-
Customers	415		539
Affiliated companies	525		1,036
Other Receivables	107		81
Notes receivable from affiliated companies	0		0
Materials and supplies, at average cost	492		448
Derivatives	147		165
Collateral	229		136
Prepayments and other	95		109
Total current assets	2,012		2,516
PROPERTY, PLANT AND EQUIPMENT:
In service	13,596		12,472
Less - Accumulated provision for depreciation	5,208		4,755
Property, plant and equipment in service net of accumulated provision for depreciation	8,388		7,717
Construction work in progress	1,010		1,308
Total net property, plant and equipment	9,398		9,025
INVESTMENTS:
Nuclear plant decommissioning trusts	1,365		1,276
Investment in affiliated companies	0		0
Other	10		11
Total other property and investments	1,375		1,287
ASSETS HELD FOR SALE (Note 19)	0	122	122
DEFERRED CHARGES AND OTHER ASSETS:
Accumulated deferred income tax benefits	0		0
Customer intangibles	78		95
Goodwill	23		23
Property taxes	41		41
Unamortized sale and leaseback costs	217		168
Derivatives	52		53
Other	114		172
Total deferred charges and other assets	525		552
Total assets	13,310		13,502
CURRENT LIABILITIES:
Currently payable long-term debt	506		892
Short-term borrowings	99		4
Accounts payable-
Affiliated companies	416		765
Other	248		290
Accrued taxes	102		66
Derivatives	166		110
Other	184		197
Total current liabilities	1,756		2,755
CAPITALIZATION:
Total equity	5,585		5,312
Long-term debt and other long-term obligations	2,608		2,130
Total capitalization	8,193		7,442
NONCURRENT LIABILITIES:
Deferred gain on sale and leaseback transaction	824		858
Accumulated deferred income taxes	511		741
Asset retirement obligations	841		1,015
Retirement benefits	324		185
Derivatives	14		14
Other	847		492
Total noncurrent liabilities	3,361		3,305
Total liabilities and capitalization	13,310		13,502
FES | Affiliates
CURRENT LIABILITIES:
Other Short-term Borrowings	$ 35		$ 431