FINANCING ACTIVITIES - Schedule of Average Interest Rates for Funds Borrowed from and Loaned to Utility Money Pool (Details) - Utility	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
AEP TEXAS INC.
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.87%	4.70%
Average Interest Rate for Funds Loaned	4.01%	0.00%
AEP TRANSMISSION COMPANY, LLC
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.90%	4.68%
Average Interest Rate for Funds Loaned	3.95%	4.69%
APPALACHIAN POWER COMPANY
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.91%	4.70%
Average Interest Rate for Funds Loaned	3.91%	4.69%
INDIANA MICHIGAN POWER COMPANY
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.88%	4.70%
Average Interest Rate for Funds Loaned	3.89%	0.00%
OHIO POWER COMPANY
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.95%	4.66%
Average Interest Rate for Funds Loaned	3.80%	4.70%
PUBLIC SERVICE COMPANY OF OKLAHOMA
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	3.92%	4.67%
Average Interest Rate for Funds Loaned	0.00%	4.70%
SOUTHWESTERN ELECTRIC POWER COMPANY
Short-Term Debt [Line Items]
Average Interest Rate for Funds Borrowed	4.02%	4.69%
Average Interest Rate for Funds Loaned	3.76%	0.00%