BENEFIT PLANS - Schedule of Obligations in Excess of Fair Values Accumulated Benefit Obligation (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 46.9	$ 54.8
Fair Value of Plan Assets	0.0	0.0
Underfunded Accumulated Benefit Obligation	(46.9)	(54.8)
AEP TEXAS INC.
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	302.7	2.1
Fair Value of Plan Assets	288.0	0.0
Underfunded Accumulated Benefit Obligation	(14.7)	(2.1)
APPALACHIAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.2	0.1
Fair Value of Plan Assets	0.0	0.0
Underfunded Accumulated Benefit Obligation	(0.2)	(0.1)
INDIANA MICHIGAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.9	0.7
Fair Value of Plan Assets	0.0	0.0
Underfunded Accumulated Benefit Obligation	(0.9)	(0.7)
OHIO POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.1	0.1
Fair Value of Plan Assets	0.0	0.0
Underfunded Accumulated Benefit Obligation	(0.1)	(0.1)
PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	1.1	1.2
Fair Value of Plan Assets	0.0	0.0
Underfunded Accumulated Benefit Obligation	(1.1)	(1.2)
SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	210.5	242.9
Fair Value of Plan Assets	188.9	227.5
Underfunded Accumulated Benefit Obligation	$ (21.6)	$ (15.4)