FINANCING ACTIVITIES - Schedule of Interest Expense Incurred For Funds Borrowed from Utility Money Pool (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Short-Term Debt [Line Items]
Interest Expense	$ 1,862.8	$ 1,806.9	$ 1,396.1
AEP TEXAS INC.
Short-Term Debt [Line Items]
Interest Expense	257.6	232.7	208.7
AEP TRANSMISSION COMPANY, LLC
Short-Term Debt [Line Items]
Interest Expense	214.2	194.5	162.7
APPALACHIAN POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	271.4	269.6	233.9
INDIANA MICHIGAN POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	133.5	136.7	125.2
OHIO POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	148.0	130.9	119.6
PUBLIC SERVICE COMPANY OF OKLAHOMA
Short-Term Debt [Line Items]
Interest Expense	95.3	103.6	83.8
SOUTHWESTERN ELECTRIC POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	105.5	147.2	137.4
Utility | Related Party | APPALACHIAN POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	6.1	16.8	5.6
Utility | Related Party | INDIANA MICHIGAN POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	4.3	3.2	2.9
Utility | Related Party | OHIO POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	3.7	9.7	2.3
Utility | Related Party | PUBLIC SERVICE COMPANY OF OKLAHOMA
Short-Term Debt [Line Items]
Interest Expense	8.9	2.3	5.5
Utility | Nonutility | Related Party | AEP TEXAS INC.
Short-Term Debt [Line Items]
Interest Expense	6.7	10.8	0.9
Utility | Nonutility | Related Party | SOUTHWESTERN ELECTRIC POWER COMPANY
Short-Term Debt [Line Items]
Interest Expense	13.6	7.9	4.9
Utility | Direct Borrowing | Related Party | AEP TRANSMISSION COMPANY, LLC
Short-Term Debt [Line Items]
Interest Expense	$ 4.3	$ 7.6	$ 3.5