v3.26.1
Document and Entity Information
Apr. 01, 2026
Document And Entity Information [Line Items]  
Amendment Flag false
Entity Central Index Key 0000007789
Document Type 8-K
Document Period End Date Apr. 01, 2026
Entity Registrant Name ASSOCIATED BANC-CORP
Entity Incorporation State Country Code WI
Entity File Number 001-31343
Entity Tax Identification Number 39-1098068
Entity Address, Address Line One 433 Main Street
Entity Address, City or Town Green Bay
Entity Address, State or Province WI
Entity Address, Postal Zip Code 54301
City Area Code 920
Local Phone Number 491-7500
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Common Stock [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Common stock, par value $0.01 per share
Trading Symbol ASB
Security Exchange Name NYSE
Series E Preferred Stock [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Depositary Shrs, each representing 1/40th intrst in a shr of 5.875% Non-Cum. Perp Pref Stock, Srs E
Trading Symbol ASB PrE
Security Exchange Name NYSE
Series F Preferred Stock [Member]  
Document And Entity Information [Line Items]  
Security 12b Title Depositary Shrs, each representing 1/40th intrst in a shr of 5.625% Non-Cum. Perp Pref Stock, Srs F
Trading Symbol ASB PrF
Security Exchange Name NYSE
Senior Subordinated Notes [Member]  
Document And Entity Information [Line Items]  
Security 12b Title 6.625% Fixed-Rate Reset Subordinated Notes due 2033
Trading Symbol ASBA
Security Exchange Name NYSE