COMMITMENTS, GUARANTEES AND CONTINGENCIES - Narrative (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) site unit millsPerKWh MW	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2024 USD ($)	Mar. 30, 2024 USD ($)
Other Commitments [Line Items]
Litigation settlement	$ 450,000
Loss contingency, loss in period		$ 19,000,000
Cook Plant
Other Commitments [Line Items]
Nuclear contingencies, producing power | MW			2,296
INDIANA MICHIGAN POWER COMPANY | Cook Plant
Other Commitments [Line Items]
Nuclear contingencies, number of units | unit			2
Environmental Response Compensation and Liability Act (Superfund) and State Remediation
Other Commitments [Line Items]
Number of additional sites for which could lead to potentially responsible party designation | site			11
Environmental Response Compensation and Liability Act (Superfund) and State Remediation | AEP Generation Resources Inc.
Other Commitments [Line Items]
Number of sites for which potentially responsible party designation was named | site			1
Environmental Response Compensation and Liability Act (Superfund) and State Remediation | SOUTHWESTERN ELECTRIC POWER COMPANY
Other Commitments [Line Items]
Number of sites for which potentially responsible party designation was named | site			1
Environmental Response Compensation and Liability Act (Superfund) and State Remediation | OHIO POWER COMPANY
Other Commitments [Line Items]
Number of sites for which potentially responsible party designation was named | site			2
Environmental Response Compensation and Liability Act (Superfund) and State Remediation | APPALACHIAN POWER COMPANY
Other Commitments [Line Items]
Number of sites for which potentially responsible party designation was named | site			1
Decommissioning and Low Level Waste Accumulation Disposal
Other Commitments [Line Items]
Cost of decommissioning and disposal of radioactive waste			$ 2,400,000,000
Additional ongoing costs for post decommissioning storage of SNF			7,000,000
Subsequent decommissioning of the spent fuel storage facility			45,000,000
Amount recovered in rates for decommissioning costs			1,000,000	$ 2,000,000	$ 2,000,000
Decommissioning trust assets amount			4,000,000,000	3,500,000,000
Decommissioning and Low Level Waste Accumulation Disposal | INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Cost of decommissioning and disposal of radioactive waste			2,400,000,000
Additional ongoing costs for post decommissioning storage of SNF			7,000,000
Subsequent decommissioning of the spent fuel storage facility			45,000,000
Amount recovered in rates for decommissioning costs			1,000,000	2,000,000	2,000,000
Decommissioning trust assets amount			4,000,000,000	3,500,000,000
Spent Nuclear Fuel Disposal
Other Commitments [Line Items]
DOE SNF disposal fee			0
Disposal, assessed fees and related interest			316,000,000	300,000,000
Trust fund assets one time fee obligation for nuclear fuel disposition			367,000,000	348,000,000
Spent nuclear fuel storage costs recovery			12,000,000	21,000,000	3,000,000
Settlement amount recoverable for dry cask current			11,000,000	12,000,000
Settlement amount recoverable for dry cask noncurrent			$ 15,000,000	9,000,000
Spent Nuclear Fuel Disposal | INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Spent nuclear fuel obligation, fee charged | millsPerKWh			1,000,000
DOE SNF disposal fee			$ 0
Disposal, assessed fees and related interest			316,000,000	300,000,000
Trust fund assets one time fee obligation for nuclear fuel disposition			367,000,000	348,000,000
Spent nuclear fuel storage costs recovery			12,000,000	21,000,000	$ 3,000,000
Settlement amount recoverable for dry cask current			11,000,000	12,000,000
Settlement amount recoverable for dry cask noncurrent			15,000,000	$ 9,000,000
Nuclear Incident Liability
Other Commitments [Line Items]
Insurance coverage for property damage decommissioning and decontamination			2,700,000,000
Nonnuclear incident coverage for property damage decommissioning and decontamination			750,000,000
Contingent financial obligation for mutual insurance			47,000,000
Insurance protection for public liability arising from nuclear incident			16,300,000,000
Commercially available insurance			500,000,000
Assessed amount per nuclear incident			332,000,000
Deferred premium assessment annual payment			49,000,000
Commercially available insurance for catastrophic nature			500,000,000
Liability coverage under Price Anderson Act			15,800,000,000
Nuclear Incident Liability | INDIANA MICHIGAN POWER COMPANY
Other Commitments [Line Items]
Insurance coverage for property damage decommissioning and decontamination			2,700,000,000
Nonnuclear incident coverage for property damage decommissioning and decontamination			750,000,000
Contingent financial obligation for mutual insurance			47,000,000
Insurance protection for public liability arising from nuclear incident			16,300,000,000
Commercially available insurance			500,000,000
Assessed amount per nuclear incident			332,000,000
Deferred premium assessment annual payment			49,000,000
Commercially available insurance for catastrophic nature			500,000,000
Liability coverage under Price Anderson Act			15,800,000,000
Letter of Credit
Other Commitments [Line Items]
Debt instrument, face amount			450,000,000
Letter of Credit | Revolving Credit Facility
Other Commitments [Line Items]
Line of credit facility, borrowing capacity			$ 0
Letter of Credit | Revolving Credit Facility | Subsidiaries
Other Commitments [Line Items]
Line of credit facility, borrowing capacity						$ 1,200,000,000
Letter of Credit | Revolving Credit Facility | Letter Of Credit, Due March 2029
Other Commitments [Line Items]
Line of credit facility, borrowing capacity						5,000,000,000
Letter of Credit | Revolving Credit Facility | Letter Of Credit, Due March 2027
Other Commitments [Line Items]
Line of credit facility, borrowing capacity						$ 1,000,000,000	$ 4,000,000,000