FINANCING ACTIVITIES - Schedule of Long-Term Debt Information (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	$ 42,642.8	$ 40,143.2
AEP TEXAS INC.
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	6,441.6	5,889.8
AEP TRANSMISSION COMPANY, LLC
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	5,768.1	5,414.4
APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	5,660.3	5,588.3
INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	3,494.3	3,499.4
OHIO POWER COMPANY
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	3,715.7	3,366.8
PUBLIC SERVICE COMPANY OF OKLAHOMA
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	2,855.6	2,384.6
SOUTHWESTERN ELECTRIC POWER COMPANY
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	$ 3,980.8	3,646.9
Senior Unsecured Notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.32%
Senior Unsecured Notes	$ 36,410.9	$ 33,779.4
Senior Unsecured Notes | Minimum
Debt Instrument [Line Items]
Interest Rate	1.00%	1.00%
Senior Unsecured Notes | Maximum
Debt Instrument [Line Items]
Interest Rate	8.13%	8.13%
Senior Unsecured Notes | AEP TEXAS INC.
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.39%
Senior Unsecured Notes	$ 5,873.8	$ 5,027.2
Senior Unsecured Notes | AEP TEXAS INC. | Minimum
Debt Instrument [Line Items]
Interest Rate	2.10%	2.10%
Senior Unsecured Notes | AEP TEXAS INC. | Maximum
Debt Instrument [Line Items]
Interest Rate	6.76%	6.76%
Senior Unsecured Notes | AEP TRANSMISSION COMPANY, LLC
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.12%
Senior Unsecured Notes	$ 5,768.1	$ 5,414.4
Senior Unsecured Notes | AEP TRANSMISSION COMPANY, LLC | Minimum
Debt Instrument [Line Items]
Interest Rate	2.75%	2.75%
Senior Unsecured Notes | AEP TRANSMISSION COMPANY, LLC | Maximum
Debt Instrument [Line Items]
Interest Rate	5.52%	5.52%
Senior Unsecured Notes | APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.75%
Senior Unsecured Notes	$ 4,984.1	$ 4,584.9
Senior Unsecured Notes | APPALACHIAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	2.70%	2.70%
Senior Unsecured Notes | APPALACHIAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	7.00%	7.00%
Senior Unsecured Notes | INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.52%
Senior Unsecured Notes	$ 2,845.2	$ 2,843.6
Senior Unsecured Notes | INDIANA MICHIGAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	3.25%	3.25%
Senior Unsecured Notes | INDIANA MICHIGAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	6.05%	6.05%
Senior Unsecured Notes | OHIO POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.16%
Senior Unsecured Notes	$ 3,715.7	$ 3,366.8
Senior Unsecured Notes | OHIO POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	1.63%	1.63%
Senior Unsecured Notes | OHIO POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	6.60%	6.60%
Senior Unsecured Notes | PUBLIC SERVICE COMPANY OF OKLAHOMA
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.29%
Senior Unsecured Notes	$ 2,854.2	$ 2,257.8
Senior Unsecured Notes | PUBLIC SERVICE COMPANY OF OKLAHOMA | Minimum
Debt Instrument [Line Items]
Interest Rate	2.20%	2.20%
Senior Unsecured Notes | PUBLIC SERVICE COMPANY OF OKLAHOMA | Maximum
Debt Instrument [Line Items]
Interest Rate	6.63%	6.63%
Senior Unsecured Notes | SOUTHWESTERN ELECTRIC POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.73%
Senior Unsecured Notes	$ 3,649.4	$ 3,646.9
Senior Unsecured Notes | SOUTHWESTERN ELECTRIC POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	1.65%	1.65%
Senior Unsecured Notes | SOUTHWESTERN ELECTRIC POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	6.20%	6.20%
Pollution Control Bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.26%
Pollution Control Bonds	$ 1,771.3	$ 1,771.6
Pollution Control Bonds | Minimum
Debt Instrument [Line Items]
Interest Rate	0.63%	0.63%
Pollution Control Bonds | Maximum
Debt Instrument [Line Items]
Interest Rate	4.70%	4.90%
Pollution Control Bonds | AEP TEXAS INC.
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.88%
Pollution Control Bonds	$ 440.3	$ 440.3
Pollution Control Bonds | AEP TEXAS INC. | Minimum
Debt Instrument [Line Items]
Interest Rate	2.60%	2.60%
Pollution Control Bonds | AEP TEXAS INC. | Maximum
Debt Instrument [Line Items]
Interest Rate	4.55%	4.55%
Pollution Control Bonds | APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.95%
Pollution Control Bonds	$ 429.9	$ 430.0
Pollution Control Bonds | APPALACHIAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	0.63%	0.63%
Pollution Control Bonds | APPALACHIAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	4.22%	4.90%
Pollution Control Bonds | INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.49%
Pollution Control Bonds	$ 189.9	$ 189.4
Pollution Control Bonds | INDIANA MICHIGAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	0.75%	0.75%
Pollution Control Bonds | INDIANA MICHIGAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	3.05%	3.05%
Notes Payable - Nonaffiliated
Debt Instrument [Line Items]
Weighted Average Interest Rate	6.49%
Notes Payable - Nonaffiliated	$ 609.9	$ 193.3
Notes Payable - Nonaffiliated | Minimum
Debt Instrument [Line Items]
Interest Rate	0.93%	0.93%
Notes Payable - Nonaffiliated | Maximum
Debt Instrument [Line Items]
Interest Rate	6.89%	6.59%
Notes Payable - Nonaffiliated | INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.78%
Notes Payable - Nonaffiliated	$ 142.7	$ 163.3
Notes Payable - Nonaffiliated | INDIANA MICHIGAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	0.93%	0.93%
Notes Payable - Nonaffiliated | INDIANA MICHIGAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	6.41%	6.59%
Securitization Bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.08%
Securitization Bonds	$ 578.0	$ 368.9
Securitization Bonds | Minimum
Debt Instrument [Line Items]
Interest Rate	2.06%	2.06%
Securitization Bonds | Maximum
Debt Instrument [Line Items]
Interest Rate	4.88%	3.77%
Securitization Bonds | AEP TEXAS INC.
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.27%
Securitization Bonds	$ 126.8	$ 221.8
Securitization Bonds | AEP TEXAS INC. | Minimum
Debt Instrument [Line Items]
Interest Rate	2.06%	2.06%
Securitization Bonds | AEP TEXAS INC. | Maximum
Debt Instrument [Line Items]
Interest Rate	2.29%	2.84%
Securitization Bonds | APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.77%
Interest Rate	3.77%	3.77%
Securitization Bonds	$ 119.8	$ 147.0
Securitization Bonds | SOUTHWESTERN ELECTRIC POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.88%
Interest Rate	4.88%	0.00%
Securitization Bonds	$ 331.4	$ 0.0
Junior Subordinated Notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.67%
Junior Subordinated Notes	$ 2,579.1	$ 2,388.1
Junior Subordinated Notes | Minimum
Debt Instrument [Line Items]
Interest Rate	3.88%	2.03%
Junior Subordinated Notes | Maximum
Debt Instrument [Line Items]
Interest Rate	7.05%	5.70%
Spent Nuclear Fuel Obligation
Debt Instrument [Line Items]
Spent Nuclear Fuel Obligation	$ 316.3	$ 300.4
Spent Nuclear Fuel Obligation | INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Spent Nuclear Fuel Obligation	$ 316.3	300.4
Other Long-term Debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.60%
Other Long-term Debt	$ 377.3	$ 1,341.5
Other Long-term Debt | Minimum
Debt Instrument [Line Items]
Interest Rate	3.00%	3.00%
Other Long-term Debt | Maximum
Debt Instrument [Line Items]
Interest Rate	13.72%	13.72%
Other Long-term Debt | AEP TEXAS INC.
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.50%
Interest Rate	4.50%
Other Long-term Debt	$ 0.7	$ 200.5
Other Long-term Debt | AEP TEXAS INC. | Minimum
Debt Instrument [Line Items]
Interest Rate		4.50%
Other Long-term Debt | AEP TEXAS INC. | Maximum
Debt Instrument [Line Items]
Interest Rate		6.71%
Other Long-term Debt | APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.84%
Other Long-term Debt	$ 126.5	$ 426.4
Other Long-term Debt | APPALACHIAN POWER COMPANY | Minimum
Debt Instrument [Line Items]
Interest Rate	5.75%	6.46%
Other Long-term Debt | APPALACHIAN POWER COMPANY | Maximum
Debt Instrument [Line Items]
Interest Rate	13.72%	13.72%
Other Long-term Debt | INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Weighted Average Interest Rate	6.00%
Interest Rate	6.00%	6.00%
Other Long-term Debt	$ 0.2	$ 2.7
Other Long-term Debt | PUBLIC SERVICE COMPANY OF OKLAHOMA
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.00%
Interest Rate	3.00%
Other Long-term Debt	$ 1.4	$ 126.8
Other Long-term Debt | PUBLIC SERVICE COMPANY OF OKLAHOMA | Minimum
Debt Instrument [Line Items]
Interest Rate		3.00%
Other Long-term Debt | PUBLIC SERVICE COMPANY OF OKLAHOMA | Maximum
Debt Instrument [Line Items]
Interest Rate		6.71%