Mortgage Loans - Financial Effects of Single-Family Loan Restructurings Involving Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
20- and 30-year or more, amortizing fixed-rate
financing receivable, loan restructuring [Line Items]
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0.70%	0.60%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	144 months	166 months
Weighted average payment deferral or principal forbearance	$ 26	$ 15
15-year or less, amortizing fixed-rate
financing receivable, loan restructuring [Line Items]
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0.00%	0.00%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	33 months
Weighted average payment deferral or principal forbearance	$ 11	$ 10
Adjustable-rate and other
financing receivable, loan restructuring [Line Items]
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification		0.60%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	157 months	224 months
Weighted average payment deferral or principal forbearance	$ 15	$ 11

financing receivable, loan restructuring

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- Definition

Weighted average payment deferral or principal forbearance for loans restructured during the reporting period.

+ References

No definition available.

+ Details

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- Definition

Percentage of decrease in weighted average contractual interest rate of financing receivable modified for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A

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- Definition

Period of increase in weighted average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Details

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