Supplemental Guarantor Information (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			$ 62	$ 1,031
New Financing-
Long-term debt			182	503
Short-term borrowings, net			1,890	0
Redemptions and Repayments-
Long-term debt			(746)	(1,002)
Short-term borrowings, net			0	(44)
Other			(35)	(76)
Net cash provided from (used for) financing activities			831	(1,039)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(412)	(569)	(1,001)	(1,018)
Sales of investment securities held in trusts			382	1,703
Purchases of investment securities held in trusts			(420)	(1,807)
Other			(49)	(53)
Net cash used for investing activities			(1,001)	(535)
Net change in cash and cash equivalents			(108)	(543)
Cash and cash equivalents at beginning of period			202	1,019
Cash and cash equivalents at end of period	94	476	94	476
FES Corp
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			(525)	(329)
New Financing-
Long-term debt			0	0
Short-term borrowings, net			532	453
Redemptions and Repayments-
Long-term debt			0	(135)
Short-term borrowings, net			0
Other			(1)	(9)
Net cash provided from (used for) financing activities			531	309
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions			(5)	(6)
Proceeds from assets sale			0
Sales of investment securities held in trusts			0	0
Purchases of investment securities held in trusts			0	0
Loans to affiliated companies, net			1	28
Other			(2)	(2)
Net cash used for investing activities			(6)	20
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
FGCO
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			308	321
New Financing-
Long-term debt			52	140
Short-term borrowings, net			46	77
Redemptions and Repayments-
Long-term debt			(63)	(192)
Short-term borrowings, net			0
Other			(4)	(1)
Net cash provided from (used for) financing activities			31	24
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions			(44)	(109)
Proceeds from assets sale			17
Sales of investment securities held in trusts			0	0
Purchases of investment securities held in trusts			0	0
Loans to affiliated companies, net			(308)	(221)
Other			(4)	(18)
Net cash used for investing activities			(339)	(348)
Net change in cash and cash equivalents			0	(3)
Cash and cash equivalents at beginning of period			7	9
Cash and cash equivalents at end of period	7	6	7	6
Nuclear Generation Corp
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			446	200
New Financing-
Long-term debt			30	107
Short-term borrowings, net			0	0
Redemptions and Repayments-
Long-term debt			(87)	(155)
Short-term borrowings, net			(32)
Other			(1)	(1)
Net cash provided from (used for) financing activities			(90)	(49)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions			(254)	(219)
Proceeds from assets sale			0
Sales of investment securities held in trusts			109	513
Purchases of investment securities held in trusts			(127)	(545)
Loans to affiliated companies, net			(84)	100
Other			0	0
Net cash used for investing activities			(356)	(151)
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Eliminations
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			(10)	(10)
New Financing-
Long-term debt			0	0
Short-term borrowings, net			(578)	0
Redemptions and Repayments-
Long-term debt			10	10
Short-term borrowings, net			32
Other				0
Net cash provided from (used for) financing activities			(536)	10
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions			0	0
Proceeds from assets sale			0
Sales of investment securities held in trusts			0	0
Purchases of investment securities held in trusts			0	0
Loans to affiliated companies, net			546	0
Other			0	0
Net cash used for investing activities			546	0
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
FES
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities			219	182
New Financing-
Long-term debt			82	247
Short-term borrowings, net			0	530
Redemptions and Repayments-
Long-term debt			(140)	(472)
Short-term borrowings, net			0
Other			(6)	(11)
Net cash provided from (used for) financing activities			(64)	294
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions			(303)	(334)
Proceeds from assets sale			17	0
Sales of investment securities held in trusts			109	513
Purchases of investment securities held in trusts			(127)	(545)
Loans to affiliated companies, net			155	(93)
Other			(6)	(20)
Net cash used for investing activities			(155)	(479)
Net change in cash and cash equivalents			0	(3)
Cash and cash equivalents at beginning of period			7	9
Cash and cash equivalents at end of period	$ 7	$ 6	$ 7	$ 6