FINANCING ACTIVITIES - Schedule of Direct Borrowing Activity (Details) - Direct Borrowing $ in Millions	3 Months Ended
	Mar. 31, 2025 USD ($)
AEPTCo
Short-Term Debt [Line Items]
Maximum Borrowings	$ 13.7
Maximum Loans	80.3
Average Borrowings	9.5
Average Loans	26.1
Borrowings	0.0
Loans	49.4
Authorized Short-term Borrowing Limit	0.0
SWTCo
Short-Term Debt [Line Items]
Maximum Borrowings	1.8
Maximum Loans	0.0
Average Borrowings	1.8
Average Loans	0.0
Borrowings	1.8
Loans	0.0
Authorized Short-term Borrowing Limit	50.0
Midwest Transmission Holdings
Short-Term Debt [Line Items]
Maximum Borrowings	0.0
Maximum Loans	32.6
Average Borrowings	0.0
Average Loans	30.9
Borrowings	0.0
Loans	3.5
Authorized Short-term Borrowing Limit	$ 0.0