Cover page. Entities [Table] Entities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] AEP Texas Inc. [Member] AEP Texas Inc. [Member] AEP Texas Inc. AEP Transmission Co [Member] AEP Transmission Co [Member] AEP Transmission Company, LLC. Appalachian Power Co [Member] Appalachian Power Co [Member] Appalachian Power Company Member Indiana Michigan Power Co [Member] Indiana Michigan Power Co [Member] Indiana Michigan Power Company Member Ohio Power Co [Member] Ohio Power Co [Member] Ohio Power Company Member Public Service Co Of Oklahoma [Member] Public Service Co Of Oklahoma [Member] Public Service Company Of Oklahoma Member Southwestern Electric Power Co [Member] Southwestern Electric Power Co [Member] Southwestern Electric Power Company Member Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Exchange [Domain] Exchange [Domain] New York Stock Exchange NEW YORK STOCK EXCHANGE, INC. [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock, $6.50 par value Common Stock [Member] 6.125% Corporate Unit Preferred Stock [Member] Entity Information [Line Items] Entity Information [Line Items] Written Communications Written Communications Document Type Document Type Document Period End Date Document Period End Date Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Soliciting Material Soliciting Material Pre-commencement Tender Offer Pre-commencement Tender Offer Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Emerging Growth Company Entity Emerging Growth Company Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag