Consolidated Statements of Comprehensive Income (FirstEnergy Corp.) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement of Other Comprehensive Income [Abstract]
NET INCOME	$ 196	$ 306
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(46)	(53)
Amortized losses (gains) on derivative hedges	1	(2)
Change in unrealized gain on available-for-sale securities	5	10
Other comprehensive income (loss)	(40)	(45)
Income tax benefits on other comprehensive loss	(16)	(24)
Net other comprehensive income (loss)	(24)	(21)
COMPREHENSIVE INCOME	$ 172	$ 285