Consolidated Statements of Comprehensive Income (FirstEnergy Corp.) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 578	$ 299	$ 392
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(116)	(76)	(160)
Amortized gains (losses) on derivative hedges	5	(2)	3
Change in unrealized gain on available-for-sale securities	(11)	26	(10)
Other comprehensive loss	(122)	(52)	(167)
Income tax benefits on other comprehensive loss	(47)	(14)	(66)
Other comprehensive loss, net of tax	(75)	(38)	(101)
COMPREHENSIVE INCOME AVAILABLE TO FIRSTENERGY CORP.	$ 503	$ 261	$ 291