BENEFIT PLANS - Schedule of Obligations in Excess of Fair Values Projected Benefit Obligation (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	$ 3,871.8	$ 60.7
Fair Value of Plan Assets	3,666.2	0.0
Underfunded Projected Benefit Obligation	(205.6)	(60.7)
AEP TEXAS INC.
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	322.7	343.1
Fair Value of Plan Assets	288.1	332.7
Underfunded Projected Benefit Obligation	(34.6)	(10.4)
APPALACHIAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	0.5	0.4
Fair Value of Plan Assets	0.0	0.0
Underfunded Projected Benefit Obligation	(0.5)	(0.4)
INDIANA MICHIGAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	1.5	1.2
Fair Value of Plan Assets	0.0	0.0
Underfunded Projected Benefit Obligation	(1.5)	(1.2)
OHIO POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	0.4	0.3
Fair Value of Plan Assets	0.0	0.0
Underfunded Projected Benefit Obligation	(0.4)	(0.3)
PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	1.4	1.4
Fair Value of Plan Assets	0.0	0.0
Underfunded Projected Benefit Obligation	(1.4)	(1.4)
SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	227.8	261.2
Fair Value of Plan Assets	188.8	227.5
Underfunded Projected Benefit Obligation	$ (39.0)	$ (33.7)