XML 61 R43.htm IDEA: XBRL DOCUMENT
v3.23.3

FAIR VALUE MEASUREMENTS - Proceeds from the Sale of Investments in Available-for-sale Debt Securities (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Proceeds from the sale of investments in available-for-sale securities, realized gains and losses on those sales, and interest and dividend income |  |  |  |
Sale proceeds | $ 10 | $ 15 | $ 28 | $ 31
Realized gains | 0 | 0 | 0 | 1
Realized losses | 0 | (2) | (2) | (4)
Interest and dividend income | $ 3 | $ 3 | $ 9 | $ 9

X
- Definition Debt And Equity Securities, Realized Gain (Loss), Sales Proceeds + References No definition available. + Details
Name: | fe_DebtAndEquitySecuritiesRealizedGainLossSalesProceeds
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Debt and Equity Securities, Realized Gains + References No definition available. + Details
Name: | fe_DebtandEquitySecuritiesRealizedGains
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Debt and Equity Securities, Realized Losses + References No definition available. + Details
Name: | fe_DebtandEquitySecuritiesRealizedLosses
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investment Income From Trusts + References No definition available. + Details
Name: | fe_InvestmentIncomeFromTrusts
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration