PROPERTY, PLANT AND EQUIPMENT - Depreciation Rates and Useful Lives (Details)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Unregulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	39 years
Minimum | Regulated Operation
Property, Plant and Equipment [Line Items]
Generation	20 years	20 years	20 years
Transmission	15 years	15 years	15 years
Distribution	7 years	7 years	7 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | AEP TEXAS INC.
Property, Plant and Equipment [Line Items]
Transmission	50 years	50 years	50 years
Distribution	15 years	15 years	7 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | AEP TRANSMISSION COMPANY, LLC
Property, Plant and Equipment [Line Items]
Transmission	24 years	24 years	24 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	20 years	35 years	35 years
Transmission	15 years	15 years	15 years
Distribution	15 years	12 years	12 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	20 years	20 years	20 years
Transmission	44 years	44 years	44 years
Distribution	15 years	15 years	14 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | OHIO POWER COMPANY
Property, Plant and Equipment [Line Items]
Transmission	39 years	39 years	39 years
Distribution	11 years	11 years	11 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Generation	30 years	30 years	25 years
Transmission	41 years	41 years	41 years
Distribution	15 years	15 years	15 years
Other	5 years	5 years	5 years
Minimum | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	30 years	30 years	30 years
Transmission	46 years	46 years	46 years
Distribution	7 years	7 years	7 years
Other	5 years	5 years	5 years
Minimum | Unregulated Operation
Property, Plant and Equipment [Line Items]
Generation	39 years	39 years	10 years
Transmission			62 years
Other	5 years	5 years	5 years
Maximum | Regulated Operation
Property, Plant and Equipment [Line Items]
Generation	162 years	162 years	162 years
Transmission	79 years	79 years	78 years
Distribution	85 years	85 years	85 years
Other	75 years	75 years	75 years
Maximum | Regulated Operation | AEP TEXAS INC.
Property, Plant and Equipment [Line Items]
Transmission	79 years	79 years	75 years
Distribution	74 years	74 years	70 years
Other	54 years	54 years	50 years
Maximum | Regulated Operation | AEP TRANSMISSION COMPANY, LLC
Property, Plant and Equipment [Line Items]
Transmission	78 years	78 years	78 years
Other	58 years	58 years	58 years
Maximum | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	162 years	162 years	162 years
Transmission	78 years	78 years	78 years
Distribution	60 years	60 years	60 years
Other	55 years	55 years	55 years
Maximum | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	132 years	132 years	132 years
Transmission	67 years	67 years	67 years
Distribution	76 years	76 years	71 years
Other	45 years	45 years	45 years
Maximum | Regulated Operation | OHIO POWER COMPANY
Property, Plant and Equipment [Line Items]
Transmission	60 years	60 years	60 years
Distribution	70 years	70 years	70 years
Other	50 years	50 years	50 years
Maximum | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Generation	78 years	78 years	75 years
Transmission	75 years	75 years	75 years
Distribution	85 years	85 years	85 years
Other	58 years	58 years	58 years
Maximum | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Generation	65 years	65 years	65 years
Transmission	70 years	70 years	70 years
Distribution	75 years	75 years	75 years
Other	58 years	58 years	58 years
Maximum | Unregulated Operation
Property, Plant and Equipment [Line Items]
Generation	61 years	61 years	61 years
Other	35 years	35 years	35 years
Generation | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	3.00%	3.20%	3.30%
Generation | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	5.00%	4.90%	4.70%
Generation | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.30%	3.30%	3.00%
Generation | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	3.40%	3.70%	2.90%
Generation | Unregulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	1.90%
Generation | Minimum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.30%	2.70%	2.70%
Generation | Minimum | Unregulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	1.90%	1.80%	4.80%
Generation | Maximum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	5.00%	4.90%	4.70%
Generation | Maximum | Unregulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	7.60%	6.00%	6.70%
Transmission | Regulated Operation | AEP TEXAS INC.
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.30%	2.20%	2.20%
Transmission | Regulated Operation | AEP TRANSMISSION COMPANY, LLC
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.70%	2.70%	2.60%
Transmission | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.30%	2.30%	2.30%
Transmission | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.60%	2.60%	2.50%
Transmission | Regulated Operation | OHIO POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.30%	2.30%	2.30%
Transmission | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.60%	2.60%	2.60%
Transmission | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.10%	2.20%	2.20%
Transmission | Unregulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges			2.50%
Transmission | Minimum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	1.80%	2.10%	2.00%
Transmission | Maximum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.70%	2.70%	2.70%
Distribution | Regulated Operation | AEP TEXAS INC.
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.70%	2.80%	2.90%
Distribution | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	3.30%	3.50%	3.60%
Distribution | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.70%	2.80%	2.90%
Distribution | Regulated Operation | OHIO POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.90%	3.10%	3.10%
Distribution | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.80%	2.80%	2.90%
Distribution | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.90%	2.90%	2.90%
Distribution | Minimum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	2.70%	2.80%	2.90%
Distribution | Maximum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	3.40%	3.50%	3.60%
Other | Regulated Operation | AEP TEXAS INC.
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	5.80%	5.90%	6.00%
Other | Regulated Operation | AEP TRANSMISSION COMPANY, LLC
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	7.40%	7.10%	7.00%
Other | Regulated Operation | APPALACHIAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	6.60%	6.80%	7.40%
Other | Regulated Operation | INDIANA MICHIGAN POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	8.70%	8.90%	9.10%
Other | Regulated Operation | OHIO POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	6.00%	5.90%	6.40%
Other | Regulated Operation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	6.80%	6.60%	6.80%
Other | Regulated Operation | SOUTHWESTERN ELECTRIC POWER COMPANY
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	6.90%	6.70%	8.50%
Other | Unregulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	10.30%	9.70%	10.60%
Other | Minimum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	1.50%	3.00%	3.80%
Other | Maximum | Regulated Operation
Property, Plant and Equipment [Line Items]
Annual Composite Depreciation Rate Ranges	8.70%	8.90%	9.10%