REVENUE FROM CONTRACTS WITH CUSTOMERS - Affiliate Accounts Receivable (Details) - Related Party - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
AEP Texas
Disaggregation of Revenue [Line Items]
Affiliated Companies	$ 1.4	$ 0.0
AEPTCo
Disaggregation of Revenue [Line Items]
Affiliated Companies	165.0	131.6
APCo
Disaggregation of Revenue [Line Items]
Affiliated Companies	80.9	83.7
I&M
Disaggregation of Revenue [Line Items]
Affiliated Companies	58.1	55.0
OPCo
Disaggregation of Revenue [Line Items]
Affiliated Companies	61.7	63.6
PSO
Disaggregation of Revenue [Line Items]
Affiliated Companies	16.8	13.0
SWEPCo
Disaggregation of Revenue [Line Items]
Affiliated Companies	$ 25.8	$ 21.4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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