v3.26.1
Available-for-Sale Securities - Schedule of Available-for-sale Securities with Estimated Fair Values Below their Amortized Cost Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]    
Less than 12 months, Estimated Fair Value $ 4,554,541 $ 1,707,834
12 months or more, Estimated Fair Value 5,055,669 6,302,864
Total, Estimated Fair Value 9,610,210 8,010,698
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]    
Less than 12 months, Unrealized Losses (56,877) (3,617)
12 months or more, Unrealized Losses (467,163) (450,841)
Total, Unrealized Losses (524,041) (454,458)
Mortgage-backed securities    
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]    
Less than 12 months, Estimated Fair Value 3,628,201 493,323
12 months or more, Estimated Fair Value 5,055,669 6,302,864
Total, Estimated Fair Value 8,683,870 6,796,187
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]    
Less than 12 months, Unrealized Losses (51,899) (2,353)
12 months or more, Unrealized Losses (467,163) (450,841)
Total, Unrealized Losses (519,063) (453,194)
MBS-Other U.S. Obligations    
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]    
Less than 12 months, Estimated Fair Value 0 0
12 months or more, Estimated Fair Value 2,328 2,481
Total, Estimated Fair Value 2,328 2,481
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]    
Less than 12 months, Unrealized Losses 0 0
12 months or more, Unrealized Losses (11) (19)
Total, Unrealized Losses (11) (19)
MBS-GSE    
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]    
Less than 12 months, Estimated Fair Value 3,628,201 493,323
12 months or more, Estimated Fair Value 5,053,341 6,300,383
Total, Estimated Fair Value 8,681,542 6,793,706
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]    
Less than 12 months, Unrealized Losses (51,899) (2,353)
12 months or more, Unrealized Losses (467,152) (450,822)
Total, Unrealized Losses (519,052) (453,175)
Housing and U.S. obligations    
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]    
Less than 12 months, Estimated Fair Value 926,340 1,214,511
12 months or more, Estimated Fair Value 0 0
Total, Estimated Fair Value 926,340 1,214,511
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]    
Less than 12 months, Unrealized Losses (4,978) (1,264)
12 months or more, Unrealized Losses 0 0
Total, Unrealized Losses $ (4,978) $ (1,264)