FINANCING ACTIVITIES - Schedule of Proceeds on Sale of Receivables to AEP Credit (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
APCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	$ 604.8	$ 536.0
I&M
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	584.8	529.7
OPCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	860.3	845.7
PSO
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	374.8	361.6
SWEPCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	$ 428.1	$ 425.4