| Document and Entity Information | Jul. 06, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 6, 2021 |
| Entity Registrant Name | Assurant, Inc. |
| Entity Central Index Key | 0001267238 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-31978 |
| Entity Tax Identification Number | 39-1126612 |
| Entity Address, Address Line One | 55 Broadway, |
| Entity Address, Address Line Two | Suite 2901 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10006 |
| City Area Code | 212 |
| Local Phone Number | 859-7000 |
| 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] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.01 Par Value |
| Trading Symbol | AIZ |
| Security Exchange Name | NYSE |
| Senior Subordinated Notes | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 5.25% Subordinated Notes due 2061 |
| Trading Symbol | AIZN |
| Security Exchange Name | NYSE |
