ORGANIZATION AND BASIS OF PRESENTATION - Narrative (Details) customer in Thousands		12 Months Ended
	Apr. 30, 2022 USD ($)	Dec. 31, 2021 USD ($) mi² transmissionCenter agreement entity company customer MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2022 director
Regulatory Assets [Line Items]
Number of regional transmission centers | transmissionCenter		2
Regulatory assets currently being recovered through deferred returns		$ 228,000,000	$ 195,000,000
Annual composite depreciation rate		2.70%	2.70%	2.70%
Capitalized financing costs		$ 48,000,000	$ 49,000,000	$ 45,000,000
Interest costs capitalized		27,000,000	28,000,000	26,000,000
Property, plant and equipment		34,744,000,000	33,294,000,000
Concentration of risk of accounts receivable		$ 0	0
Increase (decrease) in allowance for credit loss,			121,000,000
Number of contracts that may contain variable interest | entity		1
Purchased power		$ 2,964,000,000	2,701,000,000	$ 2,927,000,000
Power Purchase Agreements
Regulatory Assets [Line Items]
Ownership interest		0.00%
Number of long term power purchase agreements maintained by parent company with Non utility generation entities | agreement		6
Global Holding
Regulatory Assets [Line Items]
Equity method investments		$ 59,000,000
Path-WV | Variable Interest Entity, Not Primary Beneficiary
Regulatory Assets [Line Items]
Equity method investments		$ 18,000,000
Percentage of high-voltage transmission line project owned by subsidiary of FE on the Allegheny Series		100.00%
Percentage of high-voltage transmission line project owned by subsidiary of AE on the West Virginia Series		50.00%
FEV | Signal Peak | Global Holding
Regulatory Assets [Line Items]
Ownership interest		33.33%
Other FE subsidiaries | Power Purchase Agreements
Regulatory Assets [Line Items]
Purchased power		$ 111,000,000	113,000,000
FET | Forecast
Regulatory Assets [Line Items]
Number of directors | director					5
Debt covenants minimum ownership interest percentage					9.90%
Debt-to-Capital terms included in sale for the first 5 years					65.00%
Debt-to-Capital terms included in sale for thereafter					70.00%
FET | North American Transmission Company II LLC | Forecast
Regulatory Assets [Line Items]
Sale of ownership interest by parent	19.90%
Sale of ownership interest by parent	$ 2,375,000,000
Number of directors | director					1
FET | FE | Forecast
Regulatory Assets [Line Items]
Number of directors | director					4
Bath County, Virginia
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW		3,003
Bath County, Virginia | AGC
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW		487
Proportionate ownership share		16.25%
Property, plant and equipment		$ 153,000,000
Bath County, Virginia | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Proportionate ownership share		60.00%
Waverly, New York | PN
Regulatory Assets [Line Items]
Number of customers served by utility operating companies | customer		4
Regulated Distribution
Regulatory Assets [Line Items]
Number of existing utility operating companies | company		10
Number of customers served by utility operating companies | customer		6,000
Service Area | mi²		65,000
Plant generation capacity (in MW's) | MW		3,580
Property, plant and equipment, net		$ 2,100,000,000
Regulated Transmission
Regulatory Assets [Line Items]
Service Area | mi²		24,500
Disposal Group, Held-for-sale | Yard Creek Generating Facility | Regulated Distribution
Regulatory Assets [Line Items]
Assets held-for-sale			45,000,000
Future Recovery of Incremental Costs
Regulatory Assets [Line Items]
Increase (decrease) in allowance for credit loss,			$ 90,000,000