COMMITMENTS, GUARANTEES AND CONTINGENCIES -Contractual Commitments (Details) $ in Millions	Dec. 31, 2024 USD ($)
Other Commitments [Line Items]
Less Than 1 Year	$ 1,194.8
2-3 Years	1,326.0
4-5 Years	810.0
After 5 Years	832.3
Total	4,163.1
APPALACHIAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	547.1
2-3 Years	408.5
4-5 Years	215.0
After 5 Years	148.2
Total	1,318.8
INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	271.4
2-3 Years	582.8
4-5 Years	452.4
After 5 Years	585.4
Total	1,892.0
PUBLIC SERVICE COMPANY OF OKLAHOMA
Other Commitments [Line Items]
Less Than 1 Year	90.3
2-3 Years	140.6
4-5 Years	62.4
After 5 Years	19.7
Total	313.0
SOUTHWESTERN ELECTRIC POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	100.9
2-3 Years	59.8
4-5 Years	0.0
After 5 Years	0.0
Total	160.7
Fuel Purchase Contracts
Other Commitments [Line Items]
Less Than 1 Year	1,002.0
2-3 Years	942.0
4-5 Years	475.7
After 5 Years	368.3
Total	2,788.0
Fuel Purchase Contracts | APPALACHIAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	506.7
2-3 Years	328.6
4-5 Years	167.0
After 5 Years	96.0
Total	1,098.3
Fuel Purchase Contracts | INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	151.5
2-3 Years	346.6
4-5 Years	220.7
After 5 Years	263.9
Total	982.7
Fuel Purchase Contracts | PUBLIC SERVICE COMPANY OF OKLAHOMA
Other Commitments [Line Items]
Less Than 1 Year	27.4
2-3 Years	17.0
4-5 Years	0.0
After 5 Years	0.0
Total	44.4
Fuel Purchase Contracts | SOUTHWESTERN ELECTRIC POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	89.4
2-3 Years	46.6
4-5 Years	0.0
After 5 Years	0.0
Total	136.0
Energy and Capacity Purchase Contracts
Other Commitments [Line Items]
Less Than 1 Year	192.8
2-3 Years	384.0
4-5 Years	334.3
After 5 Years	464.0
Total	1,375.1
Energy and Capacity Purchase Contracts | APPALACHIAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	40.4
2-3 Years	79.9
4-5 Years	48.0
After 5 Years	52.2
Total	220.5
Energy and Capacity Purchase Contracts | INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	119.9
2-3 Years	236.2
4-5 Years	231.7
After 5 Years	321.5
Total	909.3
Energy and Capacity Purchase Contracts | OHIO POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	33.2
2-3 Years	64.2
4-5 Years	66.3
After 5 Years	69.5
Total	233.2
Energy and Capacity Purchase Contracts | PUBLIC SERVICE COMPANY OF OKLAHOMA
Other Commitments [Line Items]
Less Than 1 Year	62.9
2-3 Years	123.6
4-5 Years	62.4
After 5 Years	19.7
Total	268.6
Energy and Capacity Purchase Contracts | SOUTHWESTERN ELECTRIC POWER COMPANY
Other Commitments [Line Items]
Less Than 1 Year	11.5
2-3 Years	13.2
4-5 Years	0.0
After 5 Years	0.0
Total	$ 24.7