Debt Securities Available for Sale - AFS debt securities in a continuous unrealized loss position (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	$ 699,759	$ 7,907,905
Less than 12 months Gross Unrealized Losses	23,574	437,310
12 months or more Fair Value	13,646,625	7,929,428
12 months or more Gross Unrealized Losses	1,610,844	1,322,381
Total Fair Value	14,346,384	15,837,333
Total Gross Unrealized Losses	1,634,418	1,759,691
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	490,744	6,027,786
Less than 12 months Gross Unrealized Losses	11,327	288,582
12 months or more Fair Value	7,622,733	3,244,572
12 months or more Gross Unrealized Losses	417,296	209,696
Total Fair Value	8,113,477	9,272,358
Total Gross Unrealized Losses	428,623	498,278
Collateralized Mortgage Obligations - Federal agencies
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	37,683	139,845
Less than 12 months Gross Unrealized Losses	2,204	10,655
12 months or more Fair Value	107,840	22,661
12 months or more Gross Unrealized Losses	12,390	3,705
Total Fair Value	145,523	162,506
Total Gross Unrealized Losses	14,594	14,360
Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	171,299	1,740,214
Less than 12 months Gross Unrealized Losses	10,042	138,071
12 months or more Fair Value	5,916,052	4,662,195
12 months or more Gross Unrealized Losses	1,181,158	1,108,980
Total Fair Value	6,087,351	6,402,409
Total Gross Unrealized Losses	1,191,200	1,247,051
Other
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months Fair Value	33	60
Less than 12 months Gross Unrealized Losses	1	2
12 months or more Fair Value	0	0
12 months or more Gross Unrealized Losses	0	0
Total Fair Value	33	60
Total Gross Unrealized Losses	$ 1	$ 2