Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 310	$ 288
OTHER COMPREHENSIVE LOSS:
Pension and OPEB prior service costs	(2)	(2)
Other comprehensive loss	(2)	(2)
Income tax benefits on other comprehensive loss	(1)	(1)
Other comprehensive loss, net of tax	(1)	(1)
COMPREHENSIVE INCOME	309	287
Comprehensive income attributable to noncontrolling interest	18	0
COMPREHENSIVE INCOME ATTRIBUTABLE TO FIRSTENERGY CORP.	$ 291	$ 287