v3.26.3
Investments (Narrative) (Details) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]            
Impairments on investments $ 4.1          
Allowance for credit losses 7.0 $ 8.2 $ 9.0 $ 8.1 $ 8.0 $ 5.7
Federal Home Loan Bank of Boston [Member]            
Schedule of Investments [Line Items]            
Securities on loan, fair value 316.5     339.2    
Fixed Maturities [Member]            
Schedule of Investments [Line Items]            
Impairments on investments 3.3          
Mortgage Loans [Member]            
Schedule of Investments [Line Items]            
Impairments on investments 0.8 $ 3.0        
Allowance for credit losses $ 7.0     $ 8.1