v3.26.3
Comprehensive Income (Loss) - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period     $ 3,608,975  
OCI before reclassifications     (367,572)  
Amounts reclassified from AOCI     27,445  
Other comprehensive income (loss) $ (266,709) $ 63,326 (340,127) $ 169,529
End of period 3,445,725 3,489,962 3,445,725 3,489,962
Total AOCI        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period (225,078) (230,642) (151,660) (336,845)
Other comprehensive income (loss) (266,709) 63,326 (340,127) 169,529
End of period (491,787) (167,316) (491,787) (167,316)
Investments Subtotal        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period     (69,834)  
OCI before reclassifications     (367,572)  
Amounts reclassified from AOCI     25,533  
Other comprehensive income (loss) (267,347) 62,636 (342,039) 167,461
End of period (411,873)   (411,873)  
Credit Loss Related        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period     (44,973)  
OCI before reclassifications (73,527) 9,585 (84,078) 28,378
Amounts reclassified from AOCI 10,172 (655) 17,605 (1,853)
Other comprehensive income (loss)     (66,473)  
End of period (111,446)   (111,446)  
All Other        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period     (24,861)  
OCI before reclassifications (207,985) 53,248 (283,494) 141,037
Amounts reclassified from AOCI 3,993 458 7,928 (101)
Other comprehensive income (loss)     (275,566)  
End of period (300,427)   (300,427)  
Defined Benefit Pension and Post-Retirement Plans        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning of period     (81,826)  
OCI before reclassifications     0  
Amounts reclassified from AOCI     1,912  
Other comprehensive income (loss) 638 $ 690 1,912 $ 2,068
End of period $ (79,914)   $ (79,914)