Taxes (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Sep. 30, 2009	Dec. 31, 2011	Dec. 31, 2011 FE	Dec. 31, 2010 FE	Dec. 31, 2009 FE	Dec. 31, 2011 FES	Dec. 31, 2010 FES	Dec. 31, 2009 FES	Dec. 31, 2011 OE	Dec. 31, 2010 OE	Dec. 31, 2009 OE	Dec. 31, 2011 CEI	Dec. 31, 2010 CEI	Dec. 31, 2009 CEI	Dec. 31, 2011 TE	Dec. 31, 2010 TE	Dec. 31, 2009 TE	Dec. 31, 2011 JCP&L	Dec. 31, 2010 JCP&L	Dec. 31, 2009 JCP&L	Dec. 31, 2011 Met-Ed	Dec. 31, 2010 Met-Ed	Dec. 31, 2009 Met-Ed	Dec. 31, 2011 Penelec	Dec. 31, 2010 Penelec	Dec. 31, 2009 Penelec
Changes in unrecognized tax benefits
Beginning Balance		$ 44	$ 45	$ 191	$ 219	$ 41	$ 41	$ 5	$ 2	$ 77	$ (30)	$ (1)	$ 29	$ (26)	$ 0	$ 6	$ (4)	$ 0	$ 14	$ 42	$ 2	$ 13	$ 28	$ 1	$ 11	$ 24
Increase for tax positions related to the current year	34			10	41		6	34		2	4		(1)	3		0	0		0	0		2	0		1	0
Increase due to merger with AE			97			0			0			0			0			0			0			0
Increase for tax positions related to prior years			10	2	46	8	0	2	0	0	103	1	0	52	0	0	10	0	0	0	0	0	0	0	0	0
Decrease for tax positions related to prior years			(35)	(81)	(100)	(4)	(4)	0	(2)	(19)	0	0	(15)	0	0	(6)	0	0	(21)	(28)	(2)	(2)	(15)	(1)	(5)	(13)
Decrease for settlement				(77)	(15)		(2)	0		(58)	0		(14)	0		0	0		7	0		(11)	0		(6)	0
Ending Balance		$ 44	$ 117	$ 45	$ 191	$ 45	$ 41	$ 41	$ 0	$ 2	$ 77	$ 0	$ (1)	$ 29	$ 0	$ 0	$ 6	$ 0	$ 0	$ 14	$ 0	$ 2	$ 13	$ 0	$ 1	$ 11