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Intervenor calculated revenue surplus for its filed rate year based upon the intervenor’s recommended ROE.

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Rate Matters East Companies (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Aug. 06, 2020	Jun. 30, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		$ 61,926.8	$ 60,138.1
AEP Transmission Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		10,057.1	9,490.9
Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		11,230.5	11,081.9
Indiana Michigan Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		6,992.3	6,899.7
Ohio Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		$ 7,165.7	6,907.0
2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Percent of Excess Earnings Subject to Refund		70.00%
Basis Points Over Authorized Return on Equity Considered Excess Earnings		70.00%
Requested Annual Increase		$ 65.0
Requested Return on Equity		9.90%
Amount Of Increased Depreciation Expense Requested		$ 19.0
Amount of Increase Related to Calculated Shortfall		$ 8.0
Approved Return on Common Equity		9.42%
2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member] \| Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Intervenor Calculated Revenue Surplus	$ 23.0
Intervenor Recommended Return on Common Equity	8.75%
Intervenor Calculated Earned Return during Triennial Period	11.12%
Intervenor Calculated Earnings above ROE Range	$ 59.0
2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member] \| Capital Expenditures Incurred for the Amos and Mountaineer Coal-fired Generating Plants [Member] \| Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Recommended Disallowance	121.0
2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member] \| Prepaid Pension and OPEB Assets [Member] \| Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Recommended Disallowance	$ 114.0
2019 Indiana Base Rate Case [Member] \| Indiana Michigan Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Increase Related to Annual Depreciation Rates		$ 78.0
Requested Annual Increase		$ 172.0
Requested Return on Equity		10.50%
Amount of Increase Related to Annual Depreciation Rates due to Proposed Investments		$ 52.0
Amount of Increase Related to Annual Depreciation Rates due to Increased Depreciation Expense		26.0
Approved Annual Revenue Increase		$ 77.0
Approved Return on Common Equity		9.70%
Initial Phased in Annual Increase		$ 44.0
Impact on Pretax Earnings due to Loss of Significant Contract		20.0
Kentucky Tax Reform [Member]
Public Utilities, General Disclosures [Line Items]
Refund for Excess ADIT Not Subject to Rate Normalization Requirements		11.0
2020 Kentucky Base Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase		$ 65.0
Requested Return on Equity		10.00%
Requested Recovery Amount of Previously Authorized Deferral		$ 50.0
Requested Recovery Period of Previously Authorized Deferral		5 years
2020 Ohio Base Rate Case [Member] \| Ohio Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase		$ 42.0
Requested Return on Equity		10.15%
Requested Number of Days to Delay Rate Case Proceeding		60 days
West Virginia ENEC and Vegetation Management Riders [Member]
Public Utilities, General Disclosures [Line Items]
Increase in Rider Rates related to Expanded Net Energy Cost and Vegetation Management		$ 101.0
Refund for Excess ADIT Not Subject to Rate Normalization Requirements		38.0
West Virginia ENEC and Vegetation Management Riders [Member] \| Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Increase in Rider Rates related to Expanded Net Energy Cost and Vegetation Management		81.0
Refund for Excess ADIT Not Subject to Rate Normalization Requirements		31.0
Plant Retirement Costs - Unrecovered Plant [Member] \| 2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Net Book Value of Retired Plants		93.0
Other Asset Impairment Charges		93.0
Virginia Jurisdictional AMR Meters [Member] \| 2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		52.0	51.0
Virginia Jurisdictional AMI Meters [Member] \| 2017-2019 Virginia Triennial Review [Member] \| Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		$ 83.0	$ 75.0