Consolidated Statements of Comprehensive Income (FirstEnergy Corp.) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 328	$ 222
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(18)	(31)
Amortized (gains) losses on derivative hedges	2	1
Change in unrealized gain on available-for-sale securities	28	4
Other comprehensive income (loss)	12	(26)
Income tax benefits on other comprehensive loss	4	(10)
Other comprehensive income (loss), net of tax	8	(16)
COMPREHENSIVE INCOME (LOSS)	$ 336	$ 206