v3.25.4
Net Income (Loss) Per Unrestricted Share - Reconciliation of Numerator and Denominator in Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Earnings Per Share [Abstract]      
Net Income (Loss) attributable to Kemper Corporation $ 143.3 $ 317.8 $ (272.1)
Weighted-average Unrestricted Shares Outstanding (in shares) 62,010,700 64,179,500 64,025,600
Equity-based Compensation Equivalent Shares (in shares) 595,500 596,500 0
Weighted-average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution (in shares) 62,606,200 64,776,000 64,025,600
Basic (in dollars per share) $ 2.31 $ 4.95 $ (4.25)
Diluted (in dollars per share) $ 2.29 $ 4.91 $ (4.25)