Supplemental Guarantor Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidating Statements of Income
Revenues	$ 2,624	$ 3,041	$ 7,414	$ 7,966
OPERATING EXPENSES:
Fuel	636	632	1,833	1,720
Purchased power	1,312	1,349	3,815	3,755
Other operating expenses	856	993	2,582	3,051
Provision for depreciation	282	297	859	809
General taxes	257	269	761	748
Total operating expenses	3,404	3,662	10,048	10,427
OPERATING INCOME (LOSS)	907	1,057	2,210	1,928
OTHER INCOME (EXPENSE):
Investment income	39	48	63	100
Interest expense	(230)	(267)	(750)	(763)
Capitalized interest	18	17	54	55
Total other income (expense)	(173)	(202)	(633)	(608)
INCOME (LOSS) BEFORE INCOME TAXES	734	855	1,577	1,320
INCOME TAXES (BENEFITS)	309	325	658	550
NET INCOME	425	530	919	770
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	425	530	919	770
Pension and OPEB prior service costs	(47)	(48)	(148)	(44)
Amortized gain (loss) on derivative hedges	0	2	1	13
Change in unrealized gain on available-for-sale securities	1	(26)	13	(7)
Other comprehensive income (loss)	(46)	(72)	(134)	(38)
Income taxes (benefits) on other comprehensive income (loss)	(24)	(26)	(75)	(12)
Other comprehensive income (loss), net of tax	(22)	(46)	(59)	(26)
COMPREHENSIVE INCOME	403	484	860	744
FES Corp
Consolidating Statements of Income
Revenues	1,523	1,445	4,443	4,087
OPERATING EXPENSES:
Fuel	0	6	0	13
Other operating expenses	130	162	313	483
Provision for depreciation	1	1	3	3
General taxes	20	19	60	46
Impairment of long-lived assets		0		0
Total operating expenses	1,692	1,549	4,959	4,622
OPERATING INCOME (LOSS)	(169)	(104)	(516)	(535)
OTHER INCOME (EXPENSE):
Investment income	1	0	2	1
Miscellaneous income, including net income from equity investees	317	196	854	570
Capitalized interest	0	0	0	0
Total other income (expense)	288	172	770	498
INCOME (LOSS) BEFORE INCOME TAXES	119	68	254	(37)
INCOME TAXES (BENEFITS)	18	(52)	32	(231)
NET INCOME	101	120	222	194
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	101	120	222	194
Pension and OPEB prior service costs	(5)	(5)	(2)	(14)
Amortized gain (loss) on derivative hedges	(2)	(1)	(6)	4
Change in unrealized gain on available-for-sale securities	(2)	(22)	11	(7)
Other comprehensive income (loss)	(9)	(28)	3	(17)
Income taxes (benefits) on other comprehensive income (loss)	(3)	(11)	1	(7)
Other comprehensive income (loss), net of tax	(6)	(17)	2	(10)
COMPREHENSIVE INCOME	95	103	224	184
FES Corp | Affiliates
OPERATING EXPENSES:
Purchased power	1,042	1,031	3,163	3,118
OTHER INCOME (EXPENSE):
Interest expense	(5)	0	(14)	(1)
FES Corp | Non-Affiliates
OPERATING EXPENSES:
Purchased power	499	330	1,420	959
OTHER INCOME (EXPENSE):
Interest expense	(25)	(24)	(72)	(72)
FGCO
Consolidating Statements of Income
Revenues	617	686	1,795	1,964
OPERATING EXPENSES:
Fuel	248	323	824	883
Other operating expenses	79	94	271	313
Provision for depreciation	30	33	90	96
General taxes	10	9	28	28
Impairment of long-lived assets		2		22
Total operating expenses	367	463	1,213	1,352
OPERATING INCOME (LOSS)	250	223	582	612
OTHER INCOME (EXPENSE):
Investment income	5	0	14	1
Miscellaneous income, including net income from equity investees	0	16	19	18
Capitalized interest	1	3	3	13
Total other income (expense)	(23)	(8)	(48)	(52)
INCOME (LOSS) BEFORE INCOME TAXES	227	215	534	560
INCOME TAXES (BENEFITS)	(11)	83	(19)	208
NET INCOME	238	132	553	352
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	238	132	553	352
Pension and OPEB prior service costs	(4)	(4)	(1)	(12)
Amortized gain (loss) on derivative hedges	0	0	0	0
Change in unrealized gain on available-for-sale securities	0	0	0	0
Other comprehensive income (loss)	(4)	(4)	(1)	(12)
Income taxes (benefits) on other comprehensive income (loss)	(2)	(2)	(1)	(6)
Other comprehensive income (loss), net of tax	(2)	(2)	0	(6)
COMPREHENSIVE INCOME	236	130	553	346
FGCO | Affiliates
OPERATING EXPENSES:
Purchased power	0	4	0	15
OTHER INCOME (EXPENSE):
Interest expense	(2)	(1)	(5)	(2)
FGCO | Non-Affiliates
OPERATING EXPENSES:
Purchased power	0	(2)	0	(5)
OTHER INCOME (EXPENSE):
Interest expense	(27)	(26)	(79)	(82)
Nuclear Generation Corp
Consolidating Statements of Income
Revenues	395	371	1,262	1,233
OPERATING EXPENSES:
Fuel	55	57	154	149
Other operating expenses	122	122	410	435
Provision for depreciation	41	36	114	112
General taxes	5	3	16	17
Impairment of long-lived assets		0		0
Total operating expenses	290	273	883	902
OPERATING INCOME (LOSS)	105	98	379	331
OTHER INCOME (EXPENSE):
Investment income	37	28	49	48
Miscellaneous income, including net income from equity investees	0	0	0	0
Capitalized interest	8	5	24	15
Total other income (expense)	29	16	34	12
INCOME (LOSS) BEFORE INCOME TAXES	134	114	413	343
INCOME TAXES (BENEFITS)	59	45	124	131
NET INCOME	75	69	289	212
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	75	69	289	212
Pension and OPEB prior service costs	0	0	0	0
Amortized gain (loss) on derivative hedges	0	0	0	0
Change in unrealized gain on available-for-sale securities	(1)	(22)	12	(7)
Other comprehensive income (loss)	(1)	(22)	12	(7)
Income taxes (benefits) on other comprehensive income (loss)	0	(9)	5	(3)
Other comprehensive income (loss), net of tax	(1)	(13)	7	(4)
COMPREHENSIVE INCOME	74	56	296	208
Nuclear Generation Corp | Affiliates
OPERATING EXPENSES:
Purchased power	67	55	189	189
OTHER INCOME (EXPENSE):
Interest expense	(1)	(1)	(3)	(2)
Nuclear Generation Corp | Non-Affiliates
OPERATING EXPENSES:
Purchased power	0	0	0	0
OTHER INCOME (EXPENSE):
Interest expense	(15)	(16)	(36)	(49)
Eliminations
Consolidating Statements of Income
Revenues	(978)	(1,035)	(2,971)	(3,133)
OPERATING EXPENSES:
Fuel	0	0	0	0
Other operating expenses	12	12	37	37
Provision for depreciation	(1)	(1)	(4)	(4)
General taxes	0	0	0	0
Impairment of long-lived assets		0		0
Total operating expenses	(967)	(1,024)	(2,938)	(3,100)
OPERATING INCOME (LOSS)	(11)	(11)	(33)	(33)
OTHER INCOME (EXPENSE):
Investment income	(5)	0	(15)	0
Miscellaneous income, including net income from equity investees	(316)	(203)	(848)	(571)
Capitalized interest	0	0	0	0
Total other income (expense)	(300)	(188)	(801)	(524)
INCOME (LOSS) BEFORE INCOME TAXES	(311)	(199)	(834)	(557)
INCOME TAXES (BENEFITS)	2	2	8	7
NET INCOME	(313)	(201)	(842)	(564)
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	(313)	(201)	(842)	(564)
Pension and OPEB prior service costs	4	4	1	12
Amortized gain (loss) on derivative hedges	0	0	0	0
Change in unrealized gain on available-for-sale securities	1	22	(12)	7
Other comprehensive income (loss)	5	26	(11)	19
Income taxes (benefits) on other comprehensive income (loss)	2	11	(4)	9
Other comprehensive income (loss), net of tax	3	15	(7)	10
COMPREHENSIVE INCOME	(310)	(186)	(849)	(554)
Eliminations | Affiliates
OPERATING EXPENSES:
Purchased power	(978)	(1,035)	(2,971)	(3,133)
OTHER INCOME (EXPENSE):
Interest expense	5	0	15	0
Eliminations | Non-Affiliates
OPERATING EXPENSES:
Purchased power	0	0	0	0
OTHER INCOME (EXPENSE):
Interest expense	16	15	47	47
FES
Consolidating Statements of Income
Revenues	1,557	1,467	4,529	4,151
OPERATING EXPENSES:
Fuel	303	386	978	1,045
Other operating expenses	343	390	1,031	1,268
Provision for depreciation	71	69	203	207
General taxes	35	31	104	91
Impairment of long-lived assets	0	2	0	22
Total operating expenses	1,382	1,261	4,117	3,776
OPERATING INCOME (LOSS)	175	206	412	375
OTHER INCOME (EXPENSE):
Investment income	38	28	50	50
Miscellaneous income, including net income from equity investees	1	9	25	17
Capitalized interest	9	8	27	28
Total other income (expense)	(6)	(8)	(45)	(66)
INCOME (LOSS) BEFORE INCOME TAXES	169	198	367	309
INCOME TAXES (BENEFITS)	68	78	145	115
NET INCOME	101	120	222	194
OTHER COMPREHENSIVE INCOME (LOSS):
NET INCOME	101	120	222	194
Pension and OPEB prior service costs	(5)	(5)	(2)	(14)
Amortized gain (loss) on derivative hedges	(2)	(1)	(6)	4
Change in unrealized gain on available-for-sale securities	(2)	(22)	11	(7)
Other comprehensive income (loss)	(9)	(28)	3	(17)
Income taxes (benefits) on other comprehensive income (loss)	(3)	(11)	1	(7)
Other comprehensive income (loss), net of tax	(6)	(17)	2	(10)
COMPREHENSIVE INCOME	95	103	224	184
FES | Affiliates
OPERATING EXPENSES:
Purchased power	131	55	381	189
OTHER INCOME (EXPENSE):
Interest expense	(3)	(2)	(7)	(5)
FES | Non-Affiliates
OPERATING EXPENSES:
Purchased power	499	328	1,420	954
OTHER INCOME (EXPENSE):
Interest expense	$ (51)	$ (51)	$ (140)	$ (156)