Commitments, Guarantees and Contingencies (Details) - USD ($) $ in Millions		1 Months Ended
		Apr. 22, 2021	Mar. 31, 2021
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			$ 48.6
Vertically Integrated Utilities [Member] | Subsequent Event [Member]
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Rockport Plant, Unit 2 Acquisition Price		$ 115.5
AEP Wind Holdings LLC [Member] | Generation And Marketing [Member]
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Maximum Potential Amount of Future Payments Associated with Guarantee			157.0
Guarantor Obligations, Current Carrying Value			30.0
Guarantor Obligations, Current Carrying Value, Contingent Portion			1.0
AEP Texas Inc. [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			11.3
Appalachian Power Co [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			6.3
Indiana Michigan Power Co [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			4.2
Ohio Power Co [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			7.7
Public Service Co Of Oklahoma [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			4.7
Southwestern Electric Power Co [Member]
Maximum Potential Loss [Abstract]
Max Potential Loss on Master Lease Agreements			5.4
Rockport Lease [Member]
Present Value of Future Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity [Abstract]
Minimum Lease Payments, Sale Leaseback Transactions, Next Twelve Months	[1]		147.8
Minimum Lease Payments, Sale Leaseback Transactions, within Two Years	[1]		147.6
Minimum Lease Payments, Sale Leaseback Transactions	[1]		295.4
Rockport Lease [Member] | Indiana Michigan Power Co [Member]
Present Value of Future Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity [Abstract]
Minimum Lease Payments, Sale Leaseback Transactions, Next Twelve Months			73.9
Minimum Lease Payments, Sale Leaseback Transactions, within Two Years			73.8
Minimum Lease Payments, Sale Leaseback Transactions			147.7
Boat and Barge Leases [Member]
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Guarantor Obligations, Current Carrying Value			3.0
Maximum Potential Lease Payments, AEPRO Barge and Boat Leases			47.0
Guarantee Obligations Current Carrying Value Other Liabilities Current			1.0
Guarantee Obligations Current Carrying Value Other Liabilities Noncurrent			2.0
Letters of Credit [Member]
Maximum Future Payments for Letters of Credit [Abstract]
Maximum Future Payments for Letters of Credit Issued Under the Uncommitted Facility			183.2
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Letters of Credit Limit			1,200.0
Uncommitted Facility			425.0
Letters of Credit [Member] | AEP Texas Inc. [Member]
Maximum Future Payments for Letters of Credit [Abstract]
Maximum Future Payments for Letters of Credit Issued Under the Uncommitted Facility			2.2
March 2026 | Letters of Credit [Member]
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Revolving Credit Facilities			4,000.0
March 2023 | Letters of Credit [Member]
Commitments, Guarantees and Contingencies (Textuals) [Abstract]
Revolving Credit Facilities			$ 1,000.0

[1] AEP’s future minimum lease payments include equal shares from AEGCo and I&M.