Property, Plant and Equipment (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2023	Dec. 31, 2022
Asset Retirement Obligations (ARO)
Beginning Balance	[1],[2],[3],[4],[5],[6]	$ 2,944.9
Accretion Expense	[1],[2],[3],[4],[5],[6]	86.0
Liabilities Incurred	[1],[2],[3],[4],[5],[6]	12.9
Liabilities Settled	[1],[2],[3],[4],[5],[6]	(98.1)
Asset Retirement Obligation, Revision of Estimate	[1],[2],[3],[4],[5],[6]	13.8
Ending Balance	[1],[2],[3],[4],[5],[6]	2,959.5
Competitive Contracted Renewable Portfolio
Asset Retirement Obligations (ARO)
Liabilities Settled		(31.0)
Southwestern Electric Power Co [Member]
Asset Retirement Obligations (ARO)
Beginning Balance	[1],[3],[4],[5]	282.2
Accretion Expense	[1],[3],[4],[5]	10.0
Liabilities Incurred	[1],[3],[4],[5]	7.1
Liabilities Settled	[1],[3],[4],[5]	(37.9)
Asset Retirement Obligation, Revision of Estimate	[1],[3],[4],[5]	0.4
Ending Balance	[1],[3],[4],[5]	261.8
Pirkey Power Plant and Dolet Hills Power Station | Southwestern Electric Power Co [Member]
Asset Retirement Obligations (ARO)
Liabilities Settled		(35.0)
Cook plant | Indiana Michigan Power Co [Member]
Property, Plant and Equipment (Textuals)
Asset Retirement Obligations (ARO) Liability for Nuclear Decommissioning of the Cook Plant		$ 2,050.0	$ 2,000.0

[1] In 2023, SWEPCo settled $35 million of costs related to closure/reclamation work performed due to the recent retirements of the Pirkey Plant and Dolet Hills Power Station. See “Coal-Fired Generation Plants” section of Note 4 for additional information.

[2] In August 2023, AEP completed the sale of its competitive contracted renewables portfolio to a nonaffiliated party and settled ARO liabilities of $31 million. See “Disposition of the Competitive Contracted Renewables Portfolio” section of Note 6 for additional information

[3] Includes ARO related to Sabine and DHLC.

[4] Includes ARO related to asbestos removal.

[5] Includes ARO related to ash disposal facilities.

[6] Includes ARO related to nuclear decommissioning costs for the Cook Plant of $2.05 billion and $2 billion as of September 30, 2023 and December 31, 2022, respectively.