DERIVATIVES AND HEDGING - Schedule of Notional Volume of Derivative Instruments (Details) gal in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2026 USD ($) MMBTU MWh gal	Dec. 31, 2025 USD ($) MWh MMBTU gal
Power (MWhs)
Derivative [Line Items]
Notional amount, energy measure \| MWh	371	327
Power (MWhs) \| AEP TEXAS INC.
Derivative [Line Items]
Notional amount, energy measure \| MWh	0	0
Power (MWhs) \| APCo
Derivative [Line Items]
Notional amount, energy measure \| MWh	44	23
Power (MWhs) \| I&M
Derivative [Line Items]
Notional amount, energy measure \| MWh	23	8
Power (MWhs) \| OPCo
Derivative [Line Items]
Notional amount, energy measure \| MWh	2	2
Power (MWhs) \| PSO
Derivative [Line Items]
Notional amount, energy measure \| MWh	6	8
Power (MWhs) \| SWEPCo
Derivative [Line Items]
Notional amount, energy measure \| MWh	6	6
Natural Gas (MMBtus)
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	181	166
Natural Gas (MMBtus) \| AEP TEXAS INC.
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	0	0
Natural Gas (MMBtus) \| APCo
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	46	48
Natural Gas (MMBtus) \| I&M
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	0	0
Natural Gas (MMBtus) \| OPCo
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	0	0
Natural Gas (MMBtus) \| PSO
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	53	44
Natural Gas (MMBtus) \| SWEPCo
Derivative [Line Items]
Notional amount, energy measure \| MMBTU	24	26
Heating Oil and Gasoline (Gallons)
Derivative [Line Items]
Notional amount, volume \| gal	7	8
Heating Oil and Gasoline (Gallons) \| AEP TEXAS INC.
Derivative [Line Items]
Notional amount, volume \| gal	1	2
Heating Oil and Gasoline (Gallons) \| APCo
Derivative [Line Items]
Notional amount, volume \| gal	1	1
Heating Oil and Gasoline (Gallons) \| I&M
Derivative [Line Items]
Notional amount, volume \| gal	2	2
Heating Oil and Gasoline (Gallons) \| OPCo
Derivative [Line Items]
Notional amount, volume \| gal	1	1
Heating Oil and Gasoline (Gallons) \| PSO
Derivative [Line Items]
Notional amount, volume \| gal	1	1
Heating Oil and Gasoline (Gallons) \| SWEPCo
Derivative [Line Items]
Notional amount, volume \| gal	1	1
Interest Rate (USD)
Derivative [Line Items]
Notional amount	$ 46	$ 40
Interest Rate (USD) \| AEP TEXAS INC.
Derivative [Line Items]
Notional amount	0	0
Interest Rate (USD) \| APCo
Derivative [Line Items]
Notional amount	0	0
Interest Rate (USD) \| I&M
Derivative [Line Items]
Notional amount	0	0
Interest Rate (USD) \| OPCo
Derivative [Line Items]
Notional amount	0	0
Interest Rate (USD) \| PSO
Derivative [Line Items]
Notional amount	0	0
Interest Rate (USD) \| SWEPCo
Derivative [Line Items]
Notional amount	0	0
Interest Rate
Derivative [Line Items]
Notional amount	500	500
Interest Rate \| AEP TEXAS INC.
Derivative [Line Items]
Notional amount	0	0
Interest Rate \| APCo
Derivative [Line Items]
Notional amount	0	0
Interest Rate \| I&M
Derivative [Line Items]
Notional amount	0	0
Interest Rate \| OPCo
Derivative [Line Items]
Notional amount	0	0
Interest Rate \| PSO
Derivative [Line Items]
Notional amount	0	0
Interest Rate \| SWEPCo
Derivative [Line Items]
Notional amount	$ 0	$ 0

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-5A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-5

+ Details

Name:	us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:energyItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-181

+ Details

Name:	us-gaap_DerivativeNonmonetaryNotionalAmountVolume
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:volumeItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-181

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=aeptexas_PowerContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_AEPTexasInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_AppalachianPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_IndianaMichiganPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_OhioPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_PublicServiceCompanyOfOklahomaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aeptexas_SouthwesternElectricPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=aeptexas_NaturalGasContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=aeptexas_HeatingOilAndGasolineContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=aeptexas_InterestRateOnLongTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: