LEASES - Master Lease Agreements (Details) $ in Millions	Dec. 31, 2025 USD ($)
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	$ 38
AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	9
APCo
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	5
I&M
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	4
OPCo
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	6
PSO
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	4
SWEPCo
Lessee, Lease, Description [Line Items]
Maximum Potential Loss	$ 4