BENEFIT PLANS - Schedule of Amounts Included on the Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	$ 0.0	$ 17.3
Other Current Liabilities – Accrued Short-term Benefit Liability	(5.2)	(6.7)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(200.4)	(54.0)
Funded (Underfunded) Status	(205.6)	(43.4)
Pension Plans | AEP TEXAS INC.
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	0.0	0.1
Other Current Liabilities – Accrued Short-term Benefit Liability	(0.3)	(0.3)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(34.3)	(10.2)
Funded (Underfunded) Status	(34.6)	(10.4)
Pension Plans | APPALACHIAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	35.2	46.0
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(0.4)	(0.3)
Funded (Underfunded) Status	34.8	45.7
Pension Plans | INDIANA MICHIGAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	58.2	74.8
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(1.5)	(1.2)
Funded (Underfunded) Status	56.7	73.6
Pension Plans | OHIO POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	30.3	41.4
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(0.3)	(0.3)
Funded (Underfunded) Status	30.0	41.1
Pension Plans | PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	10.9	21.8
Other Current Liabilities – Accrued Short-term Benefit Liability	(0.1)	(0.1)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(1.3)	(1.2)
Funded (Underfunded) Status	9.5	20.5
Pension Plans | SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	0.0	0.0
Other Current Liabilities – Accrued Short-term Benefit Liability	(0.1)	(0.1)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(38.9)	(33.6)
Funded (Underfunded) Status	(39.0)	(33.7)
OPEB
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	1,130.8	838.0
Other Current Liabilities – Accrued Short-term Benefit Liability	(2.2)	(2.4)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.7	(11.8)
Funded (Underfunded) Status	1,129.3	823.8
OPEB | AEP TEXAS INC.
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	96.5	71.1
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.0	0.0
Funded (Underfunded) Status	96.5	71.1
OPEB | APPALACHIAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	168.7	125.6
Other Current Liabilities – Accrued Short-term Benefit Liability	(1.4)	(1.6)
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	(13.0)	(15.6)
Funded (Underfunded) Status	154.3	108.4
OPEB | INDIANA MICHIGAN POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	139.4	105.8
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.0	0.0
Funded (Underfunded) Status	139.4	105.8
OPEB | OHIO POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	121.8	91.9
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.0	0.0
Funded (Underfunded) Status	121.8	91.9
OPEB | PUBLIC SERVICE COMPANY OF OKLAHOMA
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	62.7	46.5
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.0	0.0
Funded (Underfunded) Status	62.7	46.5
OPEB | SOUTHWESTERN ELECTRIC POWER COMPANY
Defined Benefit Plan Disclosure [Line Items]
Other Noncurrent Assets - Employee Benefits and Pension Assets	79.7	57.4
Other Current Liabilities – Accrued Short-term Benefit Liability	0.0	0.0
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability	0.0	0.0
Funded (Underfunded) Status	$ 79.7	$ 57.4