SEGMENT INFORMATION - Segment Financial Information (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Financial Information
Total revenues	[1]		$ 12,870	$ 12,459	$ 11,132
Total depreciation			1,461	1,375	1,302
Total amortization (deferral) of regulatory assets, net			(261)	(365)	269
Total DPA penalty			0	0	230
Total equity method investment earnings			175	168	31
Total interest expense			1,124	1,039	1,139
Income taxes (benefits)		$ 65	267	1,000	320
Total earnings attributable to FE from continuing operations			1,123	406	1,239
Total capital investments			3,356	2,848	2,487
Assets			48,767	46,108
Goodwill			5,618	5,618
External revenues
Segment Financial Information
Total revenues			12,870	12,459	11,132
Internal revenues
Segment Financial Information
Total revenues			0	0	0
Regulated Distribution
Segment Financial Information
Goodwill			5,004	5,004
Operating Segments | Regulated Distribution
Segment Financial Information
Total revenues			11,038	10,801	9,711
Total depreciation			1,021	967	911
Total amortization (deferral) of regulatory assets, net			(256)	(362)	260
Total equity method investment earnings			0	0	0
Total interest expense			618	526	522
Income taxes (benefits)			167	251	364
Total earnings attributable to FE from continuing operations			740	957	1,288
Total capital investments			1,631	1,605	1,437
Assets			32,929	31,749
Goodwill			5,004	5,004
Operating Segments | Regulated Distribution | External revenues
Segment Financial Information
Total revenues			10,810	10,569	9,510
Operating Segments | Regulated Distribution | Internal revenues
Segment Financial Information
Total revenues			228	232	201
Operating Segments | Regulated Transmission
Segment Financial Information
Total revenues			2,054	1,868	1,618
Total depreciation			367	335	325
Total amortization (deferral) of regulatory assets, net			(5)	(3)	9
Total equity method investment earnings			0	0	0
Total interest expense			256	230	247
Income taxes (benefits)			179	110	127
Total earnings attributable to FE from continuing operations			514	361	408
Total capital investments			1,610	1,192	958
Assets			15,155	13,835
Goodwill			614	614
Operating Segments | Regulated Transmission | External revenues
Segment Financial Information
Total revenues			2,049	1,863	1,608
Operating Segments | Regulated Transmission | Internal revenues
Segment Financial Information
Total revenues			5	5	10
Corporate/Other
Segment Financial Information
Total revenues			(222)	(210)	(197)
Total depreciation			4	7	3
Total amortization (deferral) of regulatory assets, net			0	0	0
Total DPA penalty			0	0	230
Total equity method investment earnings			175	168	31
Total interest expense			334	350	382
Income taxes (benefits)			(79)	639	(171)
Total earnings attributable to FE from continuing operations			(131)	(912)	(457)
Total capital investments			115	51	92
Assets			683	524
Goodwill			0	0
Corporate/Other | External revenues
Segment Financial Information
Total revenues			11	27	14
Corporate/Other | Internal revenues
Segment Financial Information
Total revenues			0	0	0
Reconciling Adjustments
Segment Financial Information
Total depreciation			69	66	63
Total amortization (deferral) of regulatory assets, net			0	0	0
Total equity method investment earnings			0	0	0
Total interest expense			(84)	(67)	(12)
Income taxes (benefits)			0	0	0
Total earnings attributable to FE from continuing operations			0	0	0
Total capital investments			0	0	0
Assets			0	0
Goodwill			0	0
Reconciling Adjustments | External revenues
Segment Financial Information
Total revenues			0	0	0
Reconciling Adjustments | Internal revenues
Segment Financial Information
Total revenues			$ (233)	$ (237)	$ (211)

[1] Includes excise and gross receipts tax collections of $420 million, $406 million and $374 million in 2023, 2022 and 2021, respectively.