FINANCING ACTIVITIES - Schedule of Proceeds on Sale of Receivables to AEP Credit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
APCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	$ 1,992	$ 1,954	$ 1,820
I&M
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	2,415	2,105	2,055
OPCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	3,332	3,198	3,339
PSO
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	1,926	1,781	1,945
SWEPCo
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of receivables to AEP Credit	$ 1,853	$ 1,838	$ 1,866