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BENEFIT PLANS - Schedule of Amounts Included in Regulatory Assets, Deferred Income Taxes and AOCI (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Pension Plans |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | $ 1,153.5 | $ 1,063.4
Prior Service Cost | 0.2 | 0.2
Actuarial Gain (Loss) During the Year | 188.0 | 129.2
Amortization of Actuarial Loss | (4.5) | (1.4)
Amounts Recognized Due to Settlement | (93.4) |
Change for the Year | 90.1 | 127.8
Pension Plans | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 1,019.8 | 938.6
Pension Plans | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 28.2 | 26.4
Pension Plans | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 105.7 | 98.6
Pension Plans | AEP TEXAS INC. |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 189.3 | 175.2
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 24.2 | 13.4
Amortization of Actuarial Loss | (0.3) | (0.1)
Amounts Recognized Due to Settlement | (9.8) |
Change for the Year | 14.1 | 13.3
Pension Plans | AEP TEXAS INC. | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 176.7 | 163.4
Pension Plans | AEP TEXAS INC. | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 2.8 | 2.7
Pension Plans | AEP TEXAS INC. | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 9.8 | 9.1
Pension Plans | APPALACHIAN POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 112.1 | 104.9
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 19.4 | 9.3
Amortization of Actuarial Loss | (0.4) | 0.0
Amounts Recognized Due to Settlement | (11.8) |
Change for the Year | 7.2 | 9.3
Pension Plans | APPALACHIAN POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 109.9 | 102.6
Pension Plans | APPALACHIAN POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.4 | 0.4
Pension Plans | APPALACHIAN POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 1.8 | 1.9
Pension Plans | INDIANA MICHIGAN POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 7.5 | (5.8)
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 23.0 | 1.2
Amortization of Actuarial Loss | (0.4) | (0.1)
Amounts Recognized Due to Settlement | (9.3) |
Change for the Year | 13.3 | 1.1
Pension Plans | INDIANA MICHIGAN POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 17.5 | 6.4
Pension Plans | INDIANA MICHIGAN POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (2.2) | (2.6)
Pension Plans | INDIANA MICHIGAN POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (7.8) | (9.6)
Pension Plans | OHIO POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 140.9 | 131.9
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 15.8 | 7.6
Amortization of Actuarial Loss | (0.3) | 0.0
Amounts Recognized Due to Settlement | (6.5) |
Change for the Year | 9.0 | 7.6
Pension Plans | OHIO POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 140.9 | 131.9
Pension Plans | OHIO POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
Pension Plans | OHIO POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
Pension Plans | PUBLIC SERVICE COMPANY OF OKLAHOMA |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 53.8 | 46.7
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 12.5 | 7.9
Amortization of Actuarial Loss | (0.2) | 0.0
Amounts Recognized Due to Settlement | (5.2) |
Change for the Year | 7.1 | 7.9
Pension Plans | PUBLIC SERVICE COMPANY OF OKLAHOMA | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 53.8 | 46.7
Pension Plans | PUBLIC SERVICE COMPANY OF OKLAHOMA | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
Pension Plans | PUBLIC SERVICE COMPANY OF OKLAHOMA | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
Pension Plans | SOUTHWESTERN ELECTRIC POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 82.9 | 89.6
Prior Service Cost | 0.0 | 0.0
Actuarial Gain (Loss) During the Year | 2.7 | 12.1
Amortization of Actuarial Loss | (0.1) | (0.1)
Amounts Recognized Due to Settlement | (9.3) |
Change for the Year | (6.7) | 12.0
Pension Plans | SOUTHWESTERN ELECTRIC POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 83.0 | 89.7
Pension Plans | SOUTHWESTERN ELECTRIC POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
Pension Plans | SOUTHWESTERN ELECTRIC POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (0.1) | (0.1)
OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | (41.6) | 201.5
Prior Service Cost | (14.7) | (27.4)
Actuarial Gain (Loss) During the Year | (240.1) | (83.7)
Amortization of Actuarial Loss | (3.0) | (14.8)
Amortization of Prior Service Credit | 12.7 | 63.1
Change for the Year | (230.4) | (35.4)
OPEB | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (55.4) | 106.1
OPEB | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (0.1) | 14.3
OPEB | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (0.8) | 53.7
OPEB | AEP TEXAS INC. |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 1.6 | 22.1
Prior Service Cost | (1.3) | (2.3)
Actuarial Gain (Loss) During the Year | (20.3) | (6.4)
Amortization of Actuarial Loss | (0.2) | (1.2)
Amortization of Prior Service Credit | 1.0 | 5.3
Change for the Year | (19.5) | (2.3)
OPEB | AEP TEXAS INC. | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.8 | 19.8
OPEB | AEP TEXAS INC. | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
OPEB | AEP TEXAS INC. | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (0.5) | 0.0
OPEB | APPALACHIAN POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | (9.9) | 27.1
Prior Service Cost | (2.3) | (4.2)
Actuarial Gain (Loss) During the Year | (36.6) | (11.1)
Amortization of Actuarial Loss | (0.4) | (2.3)
Amortization of Prior Service Credit | 1.9 | 9.2
Change for the Year | (35.1) | (4.2)
OPEB | APPALACHIAN POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (2.0) | 13.2
OPEB | APPALACHIAN POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (2.2) | 2.0
OPEB | APPALACHIAN POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (8.0) | 7.7
OPEB | INDIANA MICHIGAN POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 2.3 | 28.7
Prior Service Cost | (2.0) | (3.7)
Actuarial Gain (Loss) During the Year | (25.9) | (9.6)
Amortization of Actuarial Loss | (0.5) | (1.9)
Amortization of Prior Service Credit | 1.7 | 8.7
Change for the Year | (24.7) | (2.8)
OPEB | INDIANA MICHIGAN POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (2.9) | 19.0
OPEB | INDIANA MICHIGAN POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.7 | 1.3
OPEB | INDIANA MICHIGAN POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 2.5 | 4.7
OPEB | OHIO POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | (5.3) | 18.1
Prior Service Cost | (1.6) | (2.9)
Actuarial Gain (Loss) During the Year | (23.0) | (7.9)
Amortization of Actuarial Loss | (0.4) | (1.6)
Amortization of Prior Service Credit | 1.3 | 6.3
Change for the Year | (22.1) | (3.2)
OPEB | OHIO POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (6.9) | 15.2
OPEB | OHIO POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
OPEB | OHIO POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
OPEB | PUBLIC SERVICE COMPANY OF OKLAHOMA |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 4.7 | 17.5
Prior Service Cost | (0.9) | (1.6)
Actuarial Gain (Loss) During the Year | (12.6) | (3.7)
Amortization of Actuarial Loss | (0.2) | (0.8)
Amortization of Prior Service Credit | 0.7 | 4.0
Change for the Year | (12.1) | (0.5)
OPEB | PUBLIC SERVICE COMPANY OF OKLAHOMA | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 3.8 | 15.9
OPEB | PUBLIC SERVICE COMPANY OF OKLAHOMA | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
OPEB | PUBLIC SERVICE COMPANY OF OKLAHOMA | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.0 | 0.0
OPEB | SOUTHWESTERN ELECTRIC POWER COMPANY |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net Actuarial (Gain) Loss | 0.0 | 18.4
Prior Service Cost | (1.0) | (2.1)
Actuarial Gain (Loss) During the Year | (18.1) | (5.6)
Amortization of Actuarial Loss | (0.3) | (1.0)
Amortization of Prior Service Credit | 1.1 | 4.9
Change for the Year | (17.3) | (1.7)
OPEB | SOUTHWESTERN ELECTRIC POWER COMPANY | Regulatory Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | 0.5 | 10.2
OPEB | SOUTHWESTERN ELECTRIC POWER COMPANY | Deferred Income Taxes |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | (0.3) | 1.3
OPEB | SOUTHWESTERN ELECTRIC POWER COMPANY | Net of Tax AOCI |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Recorded as | $ (1.2) | $ 4.8

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