v3.25.2
Basis of Presentation and Significant Accounting Policies (Details)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
segment
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Number of reportable segments | segment     4      
Net income $ (29.4) $ (3.8) $ (67.6) $ (30.3)    
Net investment income, pre-tax (110.8) (108.4) (226.7) (213.8)    
Life & Retirement            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Net income (20.0) (12.3) (26.8) (24.0)    
Supplemental & Group Benefits            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Net income (7.9) (14.1) $ (19.1) (25.1)    
Revision of Prior Period, Error Correction, Adjustment            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Net income 8.1 $ 0.8   $ 2.5 $ 4.4 $ 1.3
Net investment income, pre-tax 10.2          
Revision of Prior Period, Error Correction, Adjustment | Life & Retirement            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Net income 5.3          
Revision of Prior Period, Error Correction, Adjustment | Supplemental & Group Benefits            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Net income $ 2.8