XML 243 R172.htm IDEA: XBRL DOCUMENT
v3.25.0.1

FAIR VALUE MEASUREMENTS - Fair Value of Other Temporary Investments and Cash (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Fair value | $ 4,395.1 | $ 3,860.2
Other Temporary Investments And Restricted Cash |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cost | 236.9 | 243.5
Gross unrealized gains | 26.9 | 25.9
Gross unrealized losses | (5.3) | (6.2)
Fair value | 258.5 | 263.2
Restricted Cash |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cost | 43.1 | 48.9
Gross unrealized gains | 0.0 | 0.0
Gross unrealized losses | 0.0 | 0.0
Fair value | 43.1 | 48.9
Other Cash Deposits |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cost | 13.9 | 13.9
Gross unrealized gains | 0.0 | 0.0
Gross unrealized losses | 0.0 | 0.0
Fair value | 13.9 | 13.9
Fixed Income Securities – Mutual Funds |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cost | 167.2 | 165.9
Gross unrealized gains | 0.0 | 0.0
Gross unrealized losses | (5.3) | (6.2)
Fair value | 161.9 | 159.7
Equity Securities – Mutual Funds |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cost | 12.7 | 14.8
Gross unrealized gains | 26.9 | 25.9
Gross unrealized losses | 0.0 | 0.0
Fair value | $ 39.6 | $ 40.7

X
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_OtherTemporaryInvestmentsAndRestrictedCashMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CashMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_OtherCashDepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_MutualFundsFixedIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_MutualFundsEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |