BENEFIT PLANS - Schedule of Matching Contribution Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 81.5	$ 87.9	$ 81.9
AEP TEXAS INC.
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	6.8	7.1	6.5
APPALACHIAN POWER COMPANY
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	8.0	8.4	7.8
INDIANA MICHIGAN POWER COMPANY
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	10.7	11.0	11.1
OHIO POWER COMPANY
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	7.9	8.2	7.7
PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	5.3	5.3	4.7
SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 6.5	$ 6.7	$ 6.4