Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Associated Banc-Corp
Regulatory Capital [Abstract]
Total capital	$ 3,997,205	$ 3,680,227
Total Capital Actual Ratio	12.21%	11.33%
Total Capital for Capital Adequacy Purposes Amount	$ 2,618,596	$ 2,597,589
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 Capital Actual Amount	$ 3,269,050	$ 3,229,690
Tier 1 Capital Actual Ratio	9.99%	9.95%
Tier 1 Capital for Adequacy Purposes Amount	$ 1,963,947	$ 1,948,192
Tier 1 Capital for Adequacy Purposes Ratio	6.00%	6.00%
Common Equity Tier One Capital	$ 3,074,938	$ 3,035,578
Common Equity Tier One Capital to Risk Weighted Assets	9.39%	9.35%
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,472,960	$ 1,461,144
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 Leverage Capital Actual Amount	$ 3,269,050	$ 3,229,690
Tier 1 Leverage Capital Actual Ratio	8.06%	8.59%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,622,053	$ 1,504,035
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Associated Bank, N.A.
Regulatory Capital [Abstract]
Total capital	$ 3,803,052	$ 3,594,845
Total Capital Actual Ratio	11.64%	11.09%
Total Capital for Capital Adequacy Purposes Amount	$ 2,614,469	$ 2,593,728
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Total Capital to be Well Capitalized Amount	$ 3,268,086	$ 3,242,160
Total Capital to be Well Capitalized Ratio	10.00%	10.00%
Tier 1 Capital Actual Amount	$ 3,167,182	$ 3,243,349
Tier 1 Capital Actual Ratio	9.69%	10.00%
Tier 1 Capital for Adequacy Purposes Amount	$ 1,960,852	$ 1,945,296
Tier 1 Capital for Adequacy Purposes Ratio	6.00%	6.00%
Tier 1 Capital To Be Well Capitalized Amount	$ 2,614,469	$ 2,593,728
Tier 1 Capital To Be Well Capitalized Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 3,167,182	$ 3,243,349
Common Equity Tier One Capital to Risk Weighted Assets	9.69%	10.00%
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,470,639	$ 1,458,972
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 Equity Capital to be Well Capitalized Amount	$ 2,124,256	$ 2,107,404
Tier 1 Equity Capital to be Well Capitalized Ratio	6.50%	6.50%
Tier 1 Leverage Capital Actual Amount	$ 3,167,182	$ 3,243,349
Tier 1 Leverage Capital Actual Ratio	7.82%	8.63%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,620,970	$ 1,503,666
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Leverage Capital To Be Well Capitalized Amount	$ 2,026,212	$ 1,879,583
Tier 1 Leverage Capital To Be Well Capitalized Ratio	5.00%	5.00%

Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480696/942-505-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480696/942-505-50-1B

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