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Cover Document
Dec. 07, 2020
Cover Page [Abstract]  
Entity Central Index Key 0000028412
Title of 12(b) Security Common Stock, $5 par value
Entity Incorporation, State or Country Code DE
Document Type 8-K
Document Period End Date Dec. 07, 2020
Entity Registrant Name COMERICA INCORPORATED
Entity Address, Address Line One 1717 Main Street, MC 6404
Entity Address, City or Town Dallas
Entity Address, State or Province TX
Entity Address, Postal Zip Code 75201
City Area Code (214)
Local Phone Number 462-6831
Entity File Number 1-10706
Entity Tax Identification Number 38-1998421
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Trading Symbol CMA
Security Exchange Name NYSE
Amendment Flag false
Entity Emerging Growth Company false