v3.26.3
Held-to-Maturity 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    
Carrying Value $ 12,276,485 $ 10,490,243
Estimated Fair Value    
Estimated Fair Value 12,002,522 10,384,380
Net unamortized discounts 28,500 22,100
State and local housing finance agency obligations    
Amortized Cost    
Due after one year through five years 25,100 100
Due after five years through ten years 24,235 25,920
Due after ten years 122,810 125,660
Carrying Value 172,145 151,680
Estimated Fair Value    
Due after one year through five years 24,223 100
Due after five years through ten years 23,776 25,648
Due after ten years 119,390 121,037
Estimated Fair Value 167,389 146,785
Total MBS    
Amortized Cost    
Due in one year or less 1,228,849 914,538
Due after one year through five years 3,779,844 4,565,613
Due after five years through ten years 2,360,437 1,766,708
Due after ten years 4,735,210 3,091,704
Carrying Value 12,104,340 10,338,563
Estimated Fair Value    
Due in one year or less 1,220,134 907,705
Due after one year through five years 3,639,458 4,490,399
Due after five years through ten years 2,324,322 1,749,324
Due after ten years 4,651,219 3,090,167
Estimated Fair Value $ 11,835,133 $ 10,237,595