FINANCING ACTIVITIES - Schedule of Utility Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits (Details) - Utility $ in Millions	9 Months Ended
	Sep. 30, 2025 USD ($)
AEP Texas
Short-Term Debt [Line Items]
Maximum Borrowings	$ 468.4
Maximum Loans	485.7
Average Borrowings	172.6
Average Loans	82.5
Authorized Short-term Borrowing Limit	600.0
AEP Texas | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	418.1
AEPTCo
Short-Term Debt [Line Items]
Maximum Borrowings	403.6
Maximum Loans	312.2
Average Borrowings	174.8
Average Loans	44.2
Authorized Short-term Borrowing Limit	820.0
AEPTCo | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	(89.3)
APCo
Short-Term Debt [Line Items]
Maximum Borrowings	263.5
Maximum Loans	242.1
Average Borrowings	127.8
Average Loans	26.1
Authorized Short-term Borrowing Limit	750.0
APCo | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	49.6
I&M
Short-Term Debt [Line Items]
Maximum Borrowings	145.2
Maximum Loans	157.2
Average Borrowings	71.4
Average Loans	46.2
Authorized Short-term Borrowing Limit	500.0
I&M | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	157.2
OPCo
Short-Term Debt [Line Items]
Maximum Borrowings	270.9
Maximum Loans	165.9
Average Borrowings	126.0
Average Loans	81.7
Authorized Short-term Borrowing Limit	600.0
OPCo | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	(13.0)
PSO
Short-Term Debt [Line Items]
Maximum Borrowings	505.1
Maximum Loans	391.5
Average Borrowings	221.2
Average Loans	166.1
Authorized Short-term Borrowing Limit	750.0
PSO | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	(39.7)
SWEPCo
Short-Term Debt [Line Items]
Maximum Borrowings	471.9
Maximum Loans	269.7
Average Borrowings	285.9
Average Loans	88.7
Authorized Short-term Borrowing Limit	750.0
SWEPCo | Related Party
Short-Term Debt [Line Items]
Net Loans to (Borrowings from)	$ 269.7