FINANCING ACTIVITIES - Repayments and Retirements of Debt (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2025	Mar. 31, 2025	Mar. 31, 2024
Debt Instrument [Line Items]
Principal Amount Paid		$ 229.1	$ 1,162.2
AEP Texas
Debt Instrument [Line Items]
Principal Amount Paid		12.2	11.9
AEP Texas | Subsequent Event
Debt Instrument [Line Items]
Proceeds from contributed capital	$ 250.0
AEP Texas | 2.06% Securitization Bonds
Debt Instrument [Line Items]
Principal Amount Paid		$ 10.4
Interest Rate		2.06%
I&M
Debt Instrument [Line Items]
Principal Amount Paid		$ 26.5	25.4
APCo
Debt Instrument [Line Items]
Principal Amount Paid		14.0	313.4
PSO
Debt Instrument [Line Items]
Principal Amount Paid		125.1	0.1
AEPTCo
Debt Instrument [Line Items]
Principal Amount Paid		50.0	$ 0.0
SWEPCo | Subsequent Event
Debt Instrument [Line Items]
Proceeds from contributed capital	$ 450.0
Securitization Bonds | AEP Texas | 2.29% Securitization Bonds
Debt Instrument [Line Items]
Principal Amount Paid		$ 1.8
Interest Rate		2.29%
Securitization Bonds | APCo
Debt Instrument [Line Items]
Principal Amount Paid		$ 14.0
Interest Rate		3.77%
Senior Unsecured Notes | Transource Energy
Debt Instrument [Line Items]
Principal Amount Paid		$ 1.3
Interest Rate		2.75%
Senior Unsecured Notes | PSO
Debt Instrument [Line Items]
Principal Amount Paid		$ 125.0
Interest Rate		3.17%
Senior Unsecured Notes | AEPTCo
Debt Instrument [Line Items]
Principal Amount Paid		$ 50.0
Interest Rate		3.66%
Notes Payable | I&M | Subsequent Event
Debt Instrument [Line Items]
Interest Rate	4.89%
Debt retired	$ 8.0
Debt instrument, face amount	100.0
Notes Payable | I&M | Variable Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 0.8
Notes Payable | I&M | 0.94% Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 1.3
Interest Rate		0.93%
Notes Payable | I&M | 3.44% Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 5.0
Interest Rate		3.44%
Notes Payable | I&M | 5.93% Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 4.3
Interest Rate		5.93%
Notes Payable | I&M | 6.01% Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 6.8
Interest Rate		6.01%
Notes Payable | I&M | 6.41% Note Payable
Debt Instrument [Line Items]
Principal Amount Paid		$ 8.1
Interest Rate		6.41%
Other Long-term Debt | I&M
Debt Instrument [Line Items]
Principal Amount Paid		$ 0.2
Interest Rate		6.00%
Other Long-term Debt | Transource Energy | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, face amount	1.0
Other Long-term Debt | PSO
Debt Instrument [Line Items]
Principal Amount Paid		$ 0.1
Interest Rate		3.00%
Other Long-term Debt | Wheeling Power Company | Subsequent Event
Debt Instrument [Line Items]
Debt retired	15.0
Pollution Control Bond | I&M | Subsequent Event
Debt Instrument [Line Items]
Debt retired	$ 40.0