v3.26.3
Available-for-Sale Securities - Schedule of Amortized Cost and Estimated Fair Value of Investments by Contractual Maturity (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Amortized Cost    
Amortized Cost $ 12,937,180 $ 12,377,325
Estimated Fair Value    
Estimated Fair Value 12,799,752 12,345,845
Net unamortized (premium) / discounts 95,800 44,700
Housing and U.S. obligations    
Amortized Cost    
Due in one year or less 251,049 0
Due after one year through five years 205,600 458,799
Due after five years through ten years 99,022 98,886
Due after ten years 1,664,730 1,665,775
Amortized Cost 2,220,401 2,223,460
Estimated Fair Value    
Due in one year or less 250,145 0
Due after one year through five years 197,016 461,229
Due after five year through ten years 93,641 99,043
Due after ten years 1,667,158 1,664,523
Estimated Fair Value 2,207,960 2,224,795
Mortgage-backed securities    
Amortized Cost    
Due in one year or less 199,336 492,677
Due after one year through five years 3,163,268 2,348,575
Due after five years through ten years 6,650,105 6,464,250
Due after ten years 704,070 848,363
Amortized Cost 10,716,779 10,153,865
Estimated Fair Value    
Due in one year or less 198,056 488,360
Due after one year through five years 3,105,601 2,338,486
Due after five year through ten years 6,591,004 6,456,546
Due after ten years 697,131 837,658
Estimated Fair Value $ 10,591,792 $ 10,121,050