Acquisitions and Dispositions (Details) $ in Millions		1 Months Ended			3 Months Ended					6 Months Ended	7 Months Ended	13 Months Ended
		May 31, 2021 USD ($)	Apr. 22, 2021 MW	Jun. 30, 2020 USD ($)	Mar. 31, 2022 MW	Dec. 31, 2021 MW	Jun. 30, 2021 USD ($) MW	Mar. 31, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Apr. 30, 2021 USD ($)	Jul. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)
Obligations Under Operating Leases							$ 568.4			$ 568.4			$ 638.4
Asset Retirement Obligation, Liabilities Settled	[1],[2],[3],[4]									$ 18.1
Dry Lake Solar Project
Noncash or Part Noncash Acquisition, Other Assets Acquired								$ 18.9
Dry Lake Solar Project | Noncontrolling Interest [Member]
Noncash or Part Noncash Acquisition, Other Assets Acquired								$ 18.9
Generation And Marketing [Member] | Conesville Generating Station [Member]
Payments for (Proceeds from) Removal Costs				$ 26.0					$ 98.0		$ 28.0
Asset Retirement Obligation, Liabilities Settled									$ 106.0
Generation And Marketing [Member] | Forecast [Member] | Conesville Generating Station [Member]
Payments for (Proceeds from) Removal Costs												$ 44.0
Generation And Marketing [Member] | Dry Lake Solar Project
Percentage of an Asset Acquired							75.00%			75.00%
Wind Generation MWs | MW							100
Noncash or Part Noncash Acquisition, Value of Assets Acquired							$ 114.0
Payments to Acquire Businesses, Gross		$ 11.0					103.0
Generation And Marketing [Member] | Dry Lake Solar Project | Noncontrolling Interest [Member]
Noncash or Part Noncash Acquisition, Other Assets Acquired		$ 14.0					$ 33.0
Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Wind Generation MWs | MW			199				1,485
Noncash or Part Noncash Acquisition, Value of Assets Acquired							$ 2,000.0
Payments to Acquire Businesses, Gross							270.0
Noncash or Part Noncash Acquisition, Investments Acquired							291.0
Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Subsequent Event [Member]
Wind Generation MWs | MW					999	287
Property, Plant and Equipment | Generation And Marketing [Member] | Dry Lake Solar Project
Noncash or Part Noncash Acquisition, Other Assets Acquired							146.0
AEP Texas Inc. [Member]
Obligations Under Operating Leases							67.7			$ 67.7			71.0
AEP Transmission Co [Member]
Obligations Under Operating Leases							0.7			0.7			0.4
Appalachian Power Co [Member]
Obligations Under Operating Leases							59.5			59.5			64.4
Asset Retirement Obligation, Liabilities Settled	[2],[3]									3.7
Indiana Michigan Power Co [Member]
Obligations Under Operating Leases							91.9			91.9			135.9
Ohio Power Co [Member]
Obligations Under Operating Leases							74.1			74.1			79.5
Public Service Co Of Oklahoma [Member]
Obligations Under Operating Leases							$ 47.5			$ 47.5			36.2
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Percentage of an Asset Acquired							45.50%			45.50%
Payments to Acquire Businesses, Gross							$ 123.0
Obligations Under Operating Leases							13.0			$ 13.0
Southwestern Electric Power Co [Member]
Obligations Under Operating Leases							$ 58.5			$ 58.5			$ 44.1
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Percentage of an Asset Acquired							54.50%			54.50%
Payments to Acquire Businesses, Gross							$ 147.0
Obligations Under Operating Leases							$ 15.0			$ 15.0

[1] Includes ARO related to Sabine and DHLC.

[2] Includes ARO related to asbestos removal.

[3] Includes ARO related to ash disposal facilities.

[4] Includes ARO related to nuclear decommissioning costs for the Cook Plant of $1.83 billion and $1.80 billion as of June 30, 2021 and December 31, 2020, respectively.