Rate Matters East Companies (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	$ 61,048.9	$ 60,138.1
AEP Transmission Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	9,775.4	9,490.9
Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	11,156.9	11,081.9
Indiana Michigan Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	6,917.5	6,899.7
Ohio Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	$ 7,034.4	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%
Approved Return on Common Equity	9.42%
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
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
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
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

Amount of increased depreciation expense requested.

No definition available.

Name:	aep_AmountOfIncreasedDepreciationExpenseRequested
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increased depreciation expense approved.

+ References

No definition available.

+ Details

Name:	aep_AmountofIncreaseRelatedtoAnnualDepreciationRates
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase related to annual depreciation rates due to increased depreciation expense requested.

+ References

No definition available.

+ Details

Name:	aep_AmountofIncreaseRelatedtoAnnualDepreciationRatesduetoIncreasedDepreciationExpense
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increased annual depreciation rates due to proposed investments requested.

+ References

No definition available.

+ Details

Name:	aep_AmountofIncreaseRelatedtoAnnualDepreciationRatesduetoProposedInvestments
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase related to calculated shortfall in base rate case.

+ References

No definition available.

+ Details

Name:	aep_AmountofIncreaseRelatedtoCalculatedShortfall
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of approved annual revenue increase.

+ References

No definition available.

+ Details

Name:	aep_ApprovedAnnualRevenueIncrease
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of basis points over the authorized ROE considered Excess Earnings.

+ References

No definition available.

+ Details

Name:	aep_BasisPointsOverAuthorizedReturnonEquityConsideredExcessEarnings
Namespace Prefix:	aep_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This amount represents the impact on pretax earnings due to the loss of a significant contract.

+ References

No definition available.

+ Details

Name:	aep_ImpactonPretaxEarningsduetoLossofSignificantContract
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of approved annual revenue increase that will be phased in initially.

+ References

No definition available.

+ Details

Name:	aep_InitialPhasedinAnnualIncrease
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Net Book Value of Retired Plants, before cost of removal, including materials and supplies.

+ References

No definition available.

+ Details

Name:	aep_NetBookValueofRetiredPlants
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The percent of excess earnings that are subject to refund during the Virginia Trienniel Review

+ References

No definition available.

+ Details

Name:	aep_PercentofExcessEarningsSubjecttoRefund
Namespace Prefix:	aep_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Requested annual increase.

+ References

No definition available.

+ Details

Name:	aep_RequestedAnnualIncrease
Namespace Prefix:	aep_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

Name:	us-gaap_OtherAssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of public utility's requested return on equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=aep_AEPTransmissionCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aep_AppalachianPowerCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aep_IndianaMichiganPowerCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=aep_OhioPowerCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	aep_BaseRateAxis=aep_VirginiaLegislationAffectingBiennialReviewsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	aep_BaseRateAxis=aep_A2019IndianaBaseRateCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=aep_PlantRetirementCostsUnrecoveredPlantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=aep_VirginiaJurisdictionalAMRMetersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: