FINANCING ACTIVITIES - Schedule of Fees Paid to AEP Credit for Customer Accounts Receivable Sold (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	$ 5,631.6	$ 5,085.0
APCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	1,166.3	1,093.0
I&M
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	755.1	693.8
OPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	993.5	1,013.3
PSO
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	394.0	388.0
SWEPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	530.4	516.3
Servicing Contracts | APCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	3.9	4.2
Servicing Contracts | I&M
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	3.5	4.1
Servicing Contracts | OPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	7.4	7.4
Servicing Contracts | PSO
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	2.9	3.4
Servicing Contracts | SWEPCo
Disaggregation of Revenue [Line Items]
Total Revenues from Contracts with Customers	$ 4.1	$ 4.8