v3.26.1
Debt securities available-for-sale - Schedule of Fair Value and Gross Unrealized Losses of Debt Securities Available-for-Sale Unrealized Loss Position (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]    
Less than 12 months, Fair value $ 17,250,674 $ 1,215,897
Less than 12 months, Gross unrealized losses 62,382 10,060
12 months or more, Fair value 4,696,358 5,496,062
12 months or more, Gross unrealized losses 900,266 892,407
Total, Fair value 21,947,032 6,711,959
Total, Gross unrealized losses 962,648 902,467
U.S. Treasury securities    
Debt Securities, Available-for-Sale [Line Items]    
Less than 12 months, Fair value 17,032,384 992,083
Less than 12 months, Gross unrealized losses 51,923 82
12 months or more, Fair value 440,538 943,699
12 months or more, Gross unrealized losses 21,291 20,752
Total, Fair value 17,472,922 1,935,782
Total, Gross unrealized losses 73,214 20,834
Collateralized mortgage obligations - federal agencies    
Debt Securities, Available-for-Sale [Line Items]    
Less than 12 months, Fair value 9,946 1,481
Less than 12 months, Gross unrealized losses 85 3
12 months or more, Fair value 70,494 83,266
12 months or more, Gross unrealized losses 6,709 6,509
Total, Fair value 80,440 84,747
Total, Gross unrealized losses 6,794 6,512
Mortgage-backed securities - federal agencies    
Debt Securities, Available-for-Sale [Line Items]    
Less than 12 months, Fair value 208,344 222,333
Less than 12 months, Gross unrealized losses 10,374 9,975
12 months or more, Fair value 4,185,326 4,469,097
12 months or more, Gross unrealized losses 872,266 865,146
Total, Fair value 4,393,670 4,691,430
Total, Gross unrealized losses $ 882,640 $ 875,121