BENEFIT PLANS - Schedule of Accumulated Benefit Obligation (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 3,649.3	$ 3,933.5
Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	3,602.4	3,878.7
Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	46.9	54.8
AEP TEXAS INC.
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	302.7	323.2
AEP TEXAS INC. | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	300.6	321.1
AEP TEXAS INC. | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	2.1	2.1
APPALACHIAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	434.5	485.7
APPALACHIAN POWER COMPANY | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	434.3	485.6
APPALACHIAN POWER COMPANY | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.2	0.1
INDIANA MICHIGAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	423.2	451.0
INDIANA MICHIGAN POWER COMPANY | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	422.3	450.3
INDIANA MICHIGAN POWER COMPANY | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.9	0.7
OHIO POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	326.5	354.1
OHIO POWER COMPANY | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	326.4	354.0
OHIO POWER COMPANY | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	0.1	0.1
PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	175.7	187.8
PUBLIC SERVICE COMPANY OF OKLAHOMA | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	174.6	186.6
PUBLIC SERVICE COMPANY OF OKLAHOMA | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	1.1	1.2
SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	210.5	242.9
SOUTHWESTERN ELECTRIC POWER COMPANY | Qualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	209.5	241.9
SOUTHWESTERN ELECTRIC POWER COMPANY | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 1.0	$ 1.0