XML 53 R41.htm IDEA: XBRL DOCUMENT v3.24.2.u1
INVESTMENTS - Credit Ratings (Details) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2024
Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 238.9 $ 169.3
Fair Value 235.5 166.8
AAA    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 65.0 53.0
Fair Value $ 64.1 $ 52.1
AAA | AFS securities | Credit rating    
Debt Securities, Available-for-sale [Line Items]    
Concentration percentage (in percent) 27.20% 31.20%
AA+, AA, AA-, A-1    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 102.0 $ 59.4
Fair Value $ 100.8 $ 58.8
AA+, AA, AA-, A-1 | AFS securities | Credit rating    
Debt Securities, Available-for-sale [Line Items]    
Concentration percentage (in percent) 42.80% 35.30%
A+, A, A-    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 55.2 $ 42.1
Fair Value $ 54.0 $ 41.2
A+, A, A- | AFS securities | Credit rating    
Debt Securities, Available-for-sale [Line Items]    
Concentration percentage (in percent) 22.90% 24.70%
BBB+, BBB, BBB-    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 16.7 $ 14.8
Fair Value $ 16.6 $ 14.7
BBB+, BBB, BBB- | AFS securities | Credit rating    
Debt Securities, Available-for-sale [Line Items]    
Concentration percentage (in percent) 7.10% 8.80%
Standard & Poor's Global Rating, Total | AFS securities | Credit rating    
Debt Securities, Available-for-sale [Line Items]    
Concentration percentage (in percent) 100.00% 100.00%