Held-to-Maturity Securities - Schedule of Major Security Types (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Issued, guaranteed or insured:
Amortized Cost	$ 11,962,094	$ 10,490,243
Allowance for Credit Loss (ACL)	(86)	(76)
OTTI Recognized in AOCI	0	0
Carrying Value	11,962,008	10,490,167
Gross Unrecognized Holding Gains	20,016	17,720
Gross Unrecognized Holding Losses	(156,259)	(123,507)
Fair Value	11,825,765	10,384,380
Pools of Mortgages
Issued, guaranteed or insured:
Amortized Cost	15,463	17,557
Allowance for Credit Loss (ACL)	0	0
OTTI Recognized in AOCI	0	0
Carrying Value	15,463	17,557
Gross Unrecognized Holding Gains	92	334
Gross Unrecognized Holding Losses	(7)	0
Fair Value	15,548	17,891
Collateralized Mortgage Obligations/Real Estate Mortgage Investment Conduits
Issued, guaranteed or insured:
Amortized Cost	4,705,468	2,914,512
Allowance for Credit Loss (ACL)	0	0
OTTI Recognized in AOCI	0	0
Carrying Value	4,705,468	2,914,512
Gross Unrecognized Holding Gains	15,500	9,966
Gross Unrecognized Holding Losses	(14,039)	(6,924)
Fair Value	4,706,929	2,917,554
CMBS
Issued, guaranteed or insured:
Amortized Cost	7,068,448	7,406,494
Allowance for Credit Loss (ACL)	0	0
OTTI Recognized in AOCI	0	0
Carrying Value	7,068,448	7,406,494
Gross Unrecognized Holding Gains	4,414	7,420
Gross Unrecognized Holding Losses	(138,258)	(111,764)
Fair Value	6,934,604	7,302,150
Total MBS
Issued, guaranteed or insured:
Amortized Cost	11,789,379	10,338,563
Allowance for Credit Loss (ACL)	0	0
OTTI Recognized in AOCI	0	0
Carrying Value	11,789,379	10,338,563
Gross Unrecognized Holding Gains	20,006	17,720
Gross Unrecognized Holding Losses	(152,304)	(118,688)
Fair Value	11,657,081	10,237,595
State and local housing finance agency obligations
Issued, guaranteed or insured:
Amortized Cost	172,715	151,680
Allowance for Credit Loss (ACL)	(86)	(76)
OTTI Recognized in AOCI	0	0
Carrying Value	172,629	151,604
Gross Unrecognized Holding Gains	10	0
Gross Unrecognized Holding Losses	(3,955)	(4,819)
Fair Value	$ 168,684	$ 146,785

Other Comprehensive Income (Loss), Other Than Temporary Impairment, Held To Maturity Debt Securities, Net Of Tax

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