v3.26.1
Consolidated Statements of Preferred Stock and Common Shareholders' Equity - USD ($)
$ in Millions
Total
Preferred Stock
Common Stock
Additional Paid-in Capital
Retained Earnings
AOCI Attributable to Parent
Unallocated ESSOP Shares
Treasury Stock, Common
Noncontrolling Interest
Balance at Dec. 31, 2024   $ 0.0 $ 248.8 $ 0.0 $ 5,519.7 $ (102.4) $ (47.1) $ 0.0 $ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Dividend reinvestment plan     0.0 2.7          
Net issuance of shares under stock based compensation plans     0.3            
APIC, Share-based Payment Arrangement, Recognition and Exercise       11.2          
ESSOP shares released       6.9     6.4    
Adjustments to Additional Paid in Capital, Other       23.3          
Total net income $ 449.5       449.5        
Dividends on common stock         (140.2)        
Net unrealized gains (losses) on securities, net of tax 183.3         183.3      
Foreign currency translation adjustment and other 10.8         10.8      
Treasury Stock, Value, Acquired, Cost Method               (25.2)  
Treasury Stock, Retired, Cost Method, Amount     (0.7) (12.0) (12.4)     (25.2)  
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest                 5.0
Stockholders' Equity, Other         37.2     0.0 12.9
Balance at Jun. 30, 2025   0.0 248.4 32.1 5,853.8 91.7 (40.6) 0.0 17.9
Balance at Mar. 31, 2025   0.0 248.4 0.0 5,721.2 10.8 (43.8) (19.0) 26.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Dividend reinvestment plan     0.0 0.3          
Net issuance of shares under stock based compensation plans     0.0            
APIC, Share-based Payment Arrangement, Recognition and Exercise       4.8          
ESSOP shares released       3.5     3.2    
Adjustments to Additional Paid in Capital, Other       23.3          
Total net income 204.4       204.4        
Dividends on common stock         (71.8)        
Net unrealized gains (losses) on securities, net of tax 71.6         71.6      
Foreign currency translation adjustment and other 9.2         9.2      
Treasury Stock, Value, Acquired, Cost Method               0.0  
Treasury Stock, Retired, Cost Method, Amount     0.0 0.0 0.0     0.0  
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest                 3.9
Stockholders' Equity, Other         0.0     19.0 (11.9)
Balance at Jun. 30, 2025   0.0 248.4 32.1 5,853.8 91.7 (40.6) 0.0 17.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Stockholders' Equity Attributable to Parent 5,914.0                
Balance at Dec. 31, 2025 5,928.4 0.0 246.3 23.3 5,515.2 163.1 (34.1) 0.0 14.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Dividend reinvestment plan     0.0 2.8          
Net issuance of shares under stock based compensation plans     0.4            
APIC, Share-based Payment Arrangement, Recognition and Exercise       18.0          
ESSOP shares released       8.2     6.5    
Adjustments to Additional Paid in Capital, Other       0.0          
Total net income 652.4       652.4        
Dividends on common stock         (153.3)        
Net unrealized gains (losses) on securities, net of tax (147.2)         (147.2)      
Foreign currency translation adjustment and other (7.4)         (7.4)      
Treasury Stock, Value, Acquired, Cost Method               (221.5)  
Treasury Stock, Retired, Cost Method, Amount     (5.4) (52.3) (163.7)     (221.5)  
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest                 1.5
Stockholders' Equity, Other         0.0     0.0 (1.0)
Balance at Jun. 30, 2026 6,087.8 0.0 241.4 0.0 5,850.5 8.5 (27.6) 0.0 15.0
Balance at Mar. 31, 2026   0.0 242.8 0.0 5,652.4 47.5 (30.8) 0.0 13.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Dividend reinvestment plan     0.0 0.3          
Net issuance of shares under stock based compensation plans     0.0            
APIC, Share-based Payment Arrangement, Recognition and Exercise       7.4          
ESSOP shares released       3.8     3.2    
Adjustments to Additional Paid in Capital, Other       0.0          
Total net income 322.3       322.3        
Dividends on common stock         (76.6)        
Net unrealized gains (losses) on securities, net of tax (34.0)         (34.0)      
Foreign currency translation adjustment and other (4.9)         (4.9)      
Treasury Stock, Value, Acquired, Cost Method               (60.7)  
Treasury Stock, Retired, Cost Method, Amount     (1.4) (11.6) (47.7)     (60.7)  
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest                 2.0
Stockholders' Equity, Other         0.0     0.0 (0.5)
Balance at Jun. 30, 2026 6,087.8 $ 0.0 $ 241.4 $ 0.0 $ 5,850.5 $ 8.5 $ (27.6) $ 0.0 $ 15.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Stockholders' Equity Attributable to Parent $ 6,072.8