FINANCING ACTIVITIES - Schedule of Fees Paid to AEP Credit for Customer Accounts Receivable Sold (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	$ 21,702	$ 19,970	$ 19,456
APCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	4,183	4,039	3,740
I&M
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	3,051	2,604	2,522
OPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	3,880	3,781	3,803
PSO
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	2,019	1,849	1,977
SWEPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	2,336	2,043	2,192
Servicing Contracts | APCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	14	16	17
Servicing Contracts | I&M
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	15	15	16
Servicing Contracts | OPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	30	30	30
Servicing Contracts | PSO
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	13	14	15
Servicing Contracts | SWEPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	$ 15	$ 18	$ 19