Consolidated Statements of Comprehensive Income (FirstEnergy Corp.) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
NET INCOME (LOSS)	$ (164)	$ 188	$ 32	$ 494
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(55)	(48)	(101)	(101)
Amortized losses on derivative hedges	1	3	2	1
Change in unrealized gain on available-for-sale securities	(8)	2	(3)	12
Other comprehensive income (loss)	(62)	(43)	(102)	(88)
Income tax benefits on other comprehensive loss	(24)	(27)	(40)	(51)
Net other comprehensive income (loss)	(38)	(16)	(62)	(37)
COMPREHENSIVE INCOME (LOSS)	(202)	172	(30)	457
Comprehensive income attributable to noncontrolling interest	0	1	0	1
COMPREHENSIVE INCOME (LOSS) AVAILABLE TO FIRSTENERGY CORP.	$ (202)	$ 171	$ (30)	$ 456