VOLUNTARY SEVERANCE PROGRAM - Summary From Program (Details) $ in Millions	9 Months Ended
	Dec. 31, 2024 USD ($)
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	$ 122.0
Settled	117.6
Remaining Balance of Severance Costs	4.4
AEP TEXAS INC.
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	19.8
Settled	19.8
Remaining Balance of Severance Costs	0.0
AEP TRANSMISSION COMPANY, LLC
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	10.7
Settled	10.7
Remaining Balance of Severance Costs	0.0
APPALACHIAN POWER COMPANY
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	26.5
Settled	26.3
Remaining Balance of Severance Costs	0.2
INDIANA MICHIGAN POWER COMPANY
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	14.8
Settled	14.6
Remaining Balance of Severance Costs	0.2
OHIO POWER COMPANY
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	14.8
Settled	14.6
Remaining Balance of Severance Costs	0.2
PUBLIC SERVICE COMPANY OF OKLAHOMA
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	10.1
Settled	10.1
Remaining Balance of Severance Costs	0.0
SOUTHWESTERN ELECTRIC POWER COMPANY
Restructuring Cost and Reserve [Line Items]
Severance Expense Incurred	16.9
Settled	16.3
Remaining Balance of Severance Costs	$ 0.6