Investments HTM Securities by Major Security Type (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	$ 16,538,542	$ 16,832,133
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss	[2]	16,538,542	16,832,133
Held-to-maturity Securities, Unrecognized Holding Gain		11,568	25,283
Held-to-maturity Securities, Unrecognized Holding Loss		(305,325)	(280,803)
Debt Securities, Held-to-maturity, Fair Value		16,244,785	16,576,613
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss		$ 67,243	$ 68,866
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Accrued interest receivable	Accrued interest receivable
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	$ 48,021	$ 49,078
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		48,021	49,078
Held-to-maturity Securities, Unrecognized Holding Gain		0	0
Held-to-maturity Securities, Unrecognized Holding Loss		(34)	(6)
Debt Securities, Held-to-maturity, Fair Value		47,987	49,072
Other Than Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	48,021	49,078
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		48,021	49,078
Held-to-maturity Securities, Unrecognized Holding Gain		0	0
Held-to-maturity Securities, Unrecognized Holding Loss		(34)	(6)
Debt Securities, Held-to-maturity, Fair Value		47,987	49,072
Single Family, Mortgage-backed Securities, Other US Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	1,084,078	1,109,265
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		1,084,078	1,109,265
Held-to-maturity Securities, Unrecognized Holding Gain		0	0
Held-to-maturity Securities, Unrecognized Holding Loss		(147,853)	(129,457)
Debt Securities, Held-to-maturity, Fair Value		936,225	979,808
Collateralized Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	16,490,521	16,783,055
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		16,490,521	16,783,055
Held-to-maturity Securities, Unrecognized Holding Gain		11,568	25,283
Held-to-maturity Securities, Unrecognized Holding Loss		(305,291)	(280,797)
Debt Securities, Held-to-maturity, Fair Value		16,196,798	16,527,541
Single Family [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	3,268,527	3,146,571
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		3,268,527	3,146,571
Held-to-maturity Securities, Unrecognized Holding Gain		7,810	23,124
Held-to-maturity Securities, Unrecognized Holding Loss		(93,208)	(79,336)
Debt Securities, Held-to-maturity, Fair Value		3,183,129	3,090,359
Multifamily [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Total	[1]	12,137,916	12,527,219
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss		12,137,916	12,527,219
Held-to-maturity Securities, Unrecognized Holding Gain		3,758	2,159
Held-to-maturity Securities, Unrecognized Holding Loss		(64,230)	(72,004)
Debt Securities, Held-to-maturity, Fair Value		$ 12,077,444	$ 12,457,374

[1] Carrying value equals amortized cost. Amortized cost of held-to-maturity securities includes adjustments made to the cost basis of an investment for accretion and amortization and excludes accrued interest receivable of (in thousands) $67,243 and $68,866 at March 31, 2024 and December 31, 2023, respectively.

[2] Carrying value equals amortized cost.