v3.26.1
Fixed Maturity Securities In An Unrealized Loss Position (Securities in an Unrealized Loss Position) (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months $ 8,781,912 $ 2,988,258
Gross Unrealized Losses, Less than 12 Months 107,147 28,408
Fair Value, 12 Months or Greater 3,613,413 4,652,566
Gross Unrealized Losses, 12 Months or Greater 410,091 415,924
Fair Value, Total 12,395,325 7,640,824
Gross Unrealized Losses, Total 517,238 444,332
U.S. government and government agency    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 2,154,637 790,077
Gross Unrealized Losses, Less than 12 Months 37,852 8,902
Fair Value, 12 Months or Greater 157,648 183,896
Gross Unrealized Losses, 12 Months or Greater 7,394 6,255
Fair Value, Total 2,312,285 973,973
Gross Unrealized Losses, Total 45,246 15,157
State and municipal    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 224,424 141,680
Gross Unrealized Losses, Less than 12 Months 2,075 1,520
Fair Value, 12 Months or Greater 882,149 1,053,168
Gross Unrealized Losses, 12 Months or Greater 35,362 36,893
Fair Value, Total 1,106,573 1,194,848
Gross Unrealized Losses, Total 37,437 38,413
Mortgage-backed    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 1,332,386 251,861
Gross Unrealized Losses, Less than 12 Months 17,449 2,265
Fair Value, 12 Months or Greater 664,655 839,061
Gross Unrealized Losses, 12 Months or Greater 126,316 130,415
Fair Value, Total 1,997,041 1,090,922
Gross Unrealized Losses, Total 143,765 132,680
Asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 1,377,150 644,346
Gross Unrealized Losses, Less than 12 Months 7,857 1,643
Fair Value, 12 Months or Greater 419,348 503,876
Gross Unrealized Losses, 12 Months or Greater 14,270 15,600
Fair Value, Total 1,796,498 1,148,222
Gross Unrealized Losses, Total 22,127 17,243
Corporate    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 2,663,342 494,240
Gross Unrealized Losses, Less than 12 Months 29,546 4,308
Fair Value, 12 Months or Greater 1,267,870 1,786,925
Gross Unrealized Losses, 12 Months or Greater 48,749 58,671
Fair Value, Total 3,931,212 2,281,165
Gross Unrealized Losses, Total 78,295 62,979
Foreign government    
Debt Securities, Available-for-sale [Line Items]    
Fair Value, Less than 12 Months 1,029,973 666,054
Gross Unrealized Losses, Less than 12 Months 12,368 9,770
Fair Value, 12 Months or Greater 221,743 285,640
Gross Unrealized Losses, 12 Months or Greater 178,000 168,090
Fair Value, Total 1,251,716 951,694
Gross Unrealized Losses, Total $ 190,368 $ 177,860