Debt Securities Available for Sale - Weighted average yield and contractual maturities of debt securities AFS (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Amortized cost
Amortized Cost	$ 19,965,296	$ 18,101,163
Allowance for credit losses
Allowance for credit losses	500	0
Gross unrealized gains
Gross unrealized gains	544	1,394
Gross unrealized loss
Gross unrealized losses	1,422,561	1,373,513
Fair Value
Debt securities available-for-sale	$ 18,542,779	$ 16,729,044
Weighted average yield
Weighted Average Yield	2.92%	2.35%
US Treasury Securities
Amortized cost
Amortized cost - Within 1 year	$ 10,828,370	$ 7,103,518
Amortized cost - After 1 to 5 years	2,275,875	3,598,209
Amortized cost - After 5 to 10 years	99,526	307,512
Amortized Cost	13,203,771	11,009,239
Allowance for credit losses
Allowance for credit losses - Within 1 year	0
Allowance for credit losses - After 1 to 5 years	0
Allowance for credit losses - After 5 to 10 years	0
Allowance for credit losses	0
Gross unrealized gains
Gross unrealized gain - Within 1 year	34	526
Gross unrealized gain - After 1 to 5 years	51	84
Gross unrealized gain - After 5 to 10 years	0	0
Gross unrealized gains	85	610
Gross unrealized loss
Gross unrealized losses - Within 1 year	61,019	59,415
Gross unrealized losses - After 1 to 5 years	123,554	170,209
Gross unrealized losses - After 5 to 10 years	11,897	33,164
Gross unrealized losses	196,470	262,788
Fair Value
Fair value - Within 1 year	10,767,385	7,044,629
Fair value - After 1 to 5 years	2,152,372	3,428,084
Fair value - After 5 to 10 years	87,629	274,348
Debt securities available-for-sale	$ 13,007,386	$ 10,747,061
Weighted average yield
Weighted average yield - Within 1 year	4.00%	3.51%
Weighted average yield - After 1 to 5 years	1.33%	1.35%
Weighted average yield - After 5 to 10 years	1.72%	1.63%
Weighted Average Yield	3.52%	2.75%
Collateralized Mortgage Obligations - Federal agencies
Amortized cost
Amortized cost - After 1 to 5 years	$ 14,014	$ 17,899
Amortized cost - After 5 to 10 years	17,931	20,503
Amortized cost - After 10 years	111,701	108,280
Amortized Cost	143,646	146,682
Allowance for credit losses
Allowance for credit losses - After 1 to 5 years	0
Allowance for credit losses - After 5 to 10 years	0
Allowance for credit losses - After 10 years	0
Allowance for credit losses	0
Gross unrealized gains
Gross unrealized gain - After 1 to 5 years	0	0
Gross unrealized gain - After 5 to 10 years	0	2
Gross unrealized gain - After 10 years	91	29
Gross unrealized gains	91	31
Gross unrealized loss
Gross unrealized losses - After 1 to 5 years	669	838
Gross unrealized losses - After 5 to 10 years	1,214	1,321
Gross unrealized losses - After 10 years	10,001	9,868
Gross unrealized losses	11,884	12,027
Fair Value
Fair value - After 1 to 5 years	13,345	17,061
Fair value - After 5 to 10 years	16,717	19,184
Fair value - After 10 years	101,791	98,441
Debt securities available-for-sale	$ 131,853	$ 134,686
Weighted average yield
Weighted average yield - After 1 to 5 years	1.54%	1.55%
Weighted average yield - After 5 to 10 years	2.30%	2.28%
Weighted average yield - After 10 years	2.76%	2.54%
Weighted Average Yield	2.59%	2.38%
Mortgage Backed Securities - federal agencies
Amortized cost
Amortized cost - Within 1 year	$ 1,323	$ 637
Amortized cost - After 1 to 5 years	73,250	82,310
Amortized cost - After 5 to 10 years	828,760	792,431
Amortized cost - After 10 years	5,712,046	6,067,353
Amortized Cost	6,615,379	6,942,731
Allowance for credit losses
Allowance for credit losses - Within 1 year	0
Allowance for credit losses - After 1 to 5 years	0
Allowance for credit losses - After 5 to 10 years	0
Allowance for credit losses - After 10 years	0
Allowance for credit losses	0
Gross unrealized gains
Gross unrealized gain - Within 1 year	0	0
Gross unrealized gain - After 1 to 5 years	5	11
Gross unrealized gain - After 5 to 10 years	140	75
Gross unrealized gain - After 10 years	223	667
Gross unrealized gains	368	753
Gross unrealized loss
Gross unrealized losses - Within 1 year	21	3
Gross unrealized losses - After 1 to 5 years	3,403	3,536
Gross unrealized losses - After 5 to 10 years	57,755	48,250
Gross unrealized losses - After 10 years	1,153,028	1,046,909
Gross unrealized losses	1,214,207	1,098,698
Fair Value
Fair value - Within 1 year	1,302	634
Fair value - After 1 to 5 years	69,852	78,785
Fair value - After 5 to 10 years	771,145	744,256
Fair value - After 10 years	4,559,241	5,021,111
Debt securities available-for-sale	$ 5,401,540	$ 5,844,786
Weighted average yield
Weighted average yield - Within 1 year	1.75%	3.72%
Weighted average yield - After 1 to 5 years	2.40%	2.34%
Weighted average yield - After 5 to 10 years	2.35%	2.28%
Weighted average yield - After 10 years	1.64%	1.64%
Weighted Average Yield	1.74%	1.72%
Other
Amortized cost
Amortized cost - Within 1 year	$ 1,000	$ 1,011
Amortized cost - After 1 to 5 years	1,500	1,500
Amortized Cost	2,500	2,511
Allowance for credit losses
Allowance for credit losses - Within 1 year	500
Allowance for credit losses - After 1 to 5 years	0
Allowance for credit losses	500
Gross unrealized gains
Gross unrealized gain - Within 1 year	0	0
Gross unrealized gain - After 1 to 5 years	0	0
Gross unrealized gains	0	0
Gross unrealized loss
Gross unrealized losses - Within 1 year	0	0
Gross unrealized losses - After 1 to 5 years	0	0
Gross unrealized losses	0	0
Fair Value
Fair value - Within 1 year	500	1,011
Fair value - After 1 to 5 years	1,500	1,500
Debt securities available-for-sale	$ 2,000	$ 2,511
Weighted average yield
Weighted average yield - Within 1 year	5.00%	4.00%
Weighted average yield - After 1 to 5 years	8.50%	8.50%
Weighted Average Yield	7.10%	6.69%