FINANCING ACTIVITIES - Schedule of Accounts Receivable and Accrued Unbilled Revenues (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
APPALACHIAN POWER COMPANY
Short-Term Debt [Line Items]
Accounts receivable and accrued unbilled revenues	$ 192.7	$ 184.6
INDIANA MICHIGAN POWER COMPANY
Short-Term Debt [Line Items]
Accounts receivable and accrued unbilled revenues	160.5	156.4
OHIO POWER COMPANY
Short-Term Debt [Line Items]
Accounts receivable and accrued unbilled revenues	470.7	541.7
PUBLIC SERVICE COMPANY OF OKLAHOMA
Short-Term Debt [Line Items]
Accounts receivable and accrued unbilled revenues	111.4	134.6
SOUTHWESTERN ELECTRIC POWER COMPANY
Short-Term Debt [Line Items]
Accounts receivable and accrued unbilled revenues	$ 153.5	$ 168.3