EARNINGS PER SHARE OF COMMON STOCK (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Attributable to FE - continuing operations		$ 406	$ 1,239	$ 1,003
Earnings Attributable to FE - discontinued operations, net of tax	[1]	0	44	76
EARNINGS ATTRIBUTABLE TO FIRSTENERGY CORP.		$ 406	$ 1,283	$ 1,079
Share Count information:
Weighted average number of basic shares outstanding (in shares)		571	545	542
Assumed exercise of dilutive stock options and awards (in shares)		1	1	1
Weighted average number of diluted shares outstanding (in shares)		572	546	543
EPS Attributable to FE:
Basic - Income from continuing operations, basic (in dollars per share)		$ 0.71	$ 2.27	$ 1.85
Basic - Discontinued operations, basic (in dollars per share)		0	0.08	0.14
Basic - EPS (in dollars per share)		0.71	2.35	1.99
Diluted - Income from continuing operations, diluted (in dollars per share)		0.71	2.27	1.85
Diluted - Discontinued operations, diluted (in dollars per share)		0	0.08	0.14
Diluted - EPS (in dollars per share)		$ 0.71	$ 2.35	$ 1.99

[1] Net of income tax benefit of $48 million and $59 million in 2021 and 2020, respectively.