Debt Securities Available for Sale - AFS debt securities in a continuous unrealized loss position (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	$ 6,054,222	$ 287,277
Less than 12 months Gross Unrealized Losses	4,810	5,566
12 months or more Fair Value	10,565,546	12,455,131
12 months or more Gross Unrealized Losses	1,417,751	1,367,947
Total Fair Value	16,619,768	12,742,408
Total Gross Unrealized Losses	1,422,561	1,373,513
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	6,003,623	244,925
Less than 12 months Gross Unrealized Losses	4,122	5,126
12 months or more Fair Value	5,111,232	6,550,941
12 months or more Gross Unrealized Losses	192,348	257,662
Total Fair Value	11,114,855	6,795,866
Total Gross Unrealized Losses	196,470	262,788
Collateralized Mortgage Obligations - Federal agencies
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	6,982	5,234
Less than 12 months Gross Unrealized Losses	26	35
12 months or more Fair Value	116,418	124,930
12 months or more Gross Unrealized Losses	11,858	11,992
Total Fair Value	123,400	130,164
Total Gross Unrealized Losses	11,884	12,027
Mortgage Backed Securities - federal agencies
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	43,617	37,118
Less than 12 months Gross Unrealized Losses	662	405
12 months or more Fair Value	5,337,896	5,779,260
12 months or more Gross Unrealized Losses	1,213,545	1,098,293
Total Fair Value	5,381,513	5,816,378
Total Gross Unrealized Losses	$ 1,214,207	$ 1,098,698