Supplemental Guarantor Information (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	$ 2,662	$ 2,320	$ 3,063
New Financing-
Long-term debt	3,745	750	604
Short-term borrowings, net	1,435	1,969	0
Redemptions and Repayments-
Long-term debt	(3,600)	(940)	(1,909)
Short-term borrowings, net	0	0	(700)
Common stock dividend payments	(920)	(920)	(881)
Tender premiums	(110)	0	0
Other	(73)	(52)	(38)
Net cash provided from (used for) financing activities	477	807	(2,924)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(2,638)	(2,678)	(2,129)
Nuclear fuel	(250)	(286)	(149)
Proceeds from asset sales	4	17	840
Sales of investment securities held in trusts	2,047	2,980	4,207
Purchases of investment securities held in trusts	(2,096)	(3,020)	(4,309)
Other	9	(43)	48
Net cash used for investing activities	(3,093)	(3,157)	(956)
Net change in cash and cash equivalents	46	(30)	(817)
Cash and cash equivalents at beginning of period	172	202	1,019
Cash and cash equivalents at end of period	218	172	202
FES
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	(1,429)	(1,063)	(790)
New Financing-
Long-term debt		0	0
Short-term borrowings, net	864	0
Equity contribution from parent	1,500
Redemptions and Repayments-
Long-term debt	(770)	(1)	(136)
Short-term borrowings, net	(244)	(707)	(1,065)
Common stock dividend payments		0
Tender premiums	(67)
Other	(4)	(1)	(9)
Net cash provided from (used for) financing activities	1,279	(709)	920
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(12)	(14)	(24)
Nuclear fuel	0	0	0
Proceeds from asset sales	0	0	9
Sales of investment securities held in trusts	0	0	0
Purchases of investment securities held in trusts	0	0	0
Loans to affiliated companies, net	163	(211)	(120)
Dividend received		2,000
Other	(1)	(3)	5
Net cash used for investing activities	150	1,772	(130)
Net change in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
FGCO
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	753	639	926
New Financing-
Long-term debt		351	140
Short-term borrowings, net	371	260
Equity contribution from parent	0
Redemptions and Repayments-
Long-term debt	(364)	(288)	(362)
Short-term borrowings, net	(505)	0	(78)
Common stock dividend payments		(2,000)
Tender premiums	0
Other	(5)	(8)	(1)
Net cash provided from (used for) financing activities	(503)	(1,685)	(145)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(256)	(273)	(205)
Nuclear fuel	0	0	0
Proceeds from asset sales	21	17	590
Sales of investment securities held in trusts	0	0	0
Purchases of investment securities held in trusts	0	0	0
Loans to affiliated companies, net	(15)	1,338	(1,157)
Dividend received		0
Other	(1)	(40)	(11)
Net cash used for investing activities	(251)	1,042	(783)
Net change in cash and cash equivalents	(1)	(4)	(2)
Cash and cash equivalents at beginning of period	3	7	9
Cash and cash equivalents at end of period	2	3	7
Nuclear Generation Corp
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	776	1,266	702
New Financing-
Long-term debt		299	107
Short-term borrowings, net	150	0
Equity contribution from parent	0
Redemptions and Repayments-
Long-term debt	(90)	(161)	(377)
Short-term borrowings, net	0	(32)	(32)
Common stock dividend payments		0
Tender premiums	0
Other		(3)	(1)
Net cash provided from (used for) financing activities	60	103	(239)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(449)	(508)	(371)
Nuclear fuel	(250)	(286)	(149)
Proceeds from asset sales	0	0	0
Sales of investment securities held in trusts	940	1,464	1,843
Purchases of investment securities held in trusts	(1,000)	(1,502)	(1,890)
Loans to affiliated companies, net	(77)	(538)	105
Dividend received		0
Other	0	1	(1)
Net cash used for investing activities	(836)	(1,369)	(463)
Net change in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Eliminations
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	(22)	(21)	(19)
New Financing-
Long-term debt		0	0
Short-term borrowings, net	(954)	(257)
Equity contribution from parent	0
Redemptions and Repayments-
Long-term debt	22	21	19
Short-term borrowings, net	749	739	1,186
Common stock dividend payments		2,000
Tender premiums	0
Other		0	0
Net cash provided from (used for) financing activities	(183)	2,503	(1,167)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	0	0	0
Nuclear fuel	0	0	0
Proceeds from asset sales	0	0	0
Sales of investment securities held in trusts	0	0	0
Purchases of investment securities held in trusts	0	0	0
Loans to affiliated companies, net	205	(482)	1,186
Dividend received		(2,000)
Other	0	0	0
Net cash used for investing activities	205	(2,482)	1,186
Net change in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
FES
Consolidated Statements of Cash Flows [Abstract]
Net cash provided from operating activities	78	821	819
New Financing-
Long-term debt	0	650	247
Short-term borrowings, net	431	3	0
Equity contribution from parent	1,500	0	0
Redemptions and Repayments-
Long-term debt	(1,202)	(429)	(856)
Short-term borrowings, net	0	0	(11)
Common stock dividend payments		0
Tender premiums	(67)	0	0
Other	(9)	(12)	(11)
Net cash provided from (used for) financing activities	653	212	(631)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(717)	(795)	(600)
Nuclear fuel	(250)	(286)	(149)
Proceeds from asset sales	21	17	599
Sales of investment securities held in trusts	940	1,464	1,843
Purchases of investment securities held in trusts	(1,000)	(1,502)	(1,890)
Loans to affiliated companies, net	276	107	14
Dividend received		0
Other	(2)	(42)	(7)
Net cash used for investing activities	(732)	(1,037)	(190)
Net change in cash and cash equivalents	(1)	(4)	(2)
Cash and cash equivalents at beginning of period	3	7	9
Cash and cash equivalents at end of period	$ 2	$ 3	$ 7