v3.26.1
Mortgage Loans Held for Portfolio (Details) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Unpaid principal balance $ 72 $ 77
Total mortgage loans held for portfolio [1] 72 77
Allowance for credit losses on mortgage loans 0 0
Mortgage loans held for portfolio, net 72 77
Fixed-rate medium-term residential mortgage loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Unpaid principal balance $ 1 $ 1
Mortgage Loans on Real Estate, Original Contractual Terms 15 years 15 years
Fixed-rate long-term residential mortgage loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Unpaid principal balance $ 71 $ 76
Conventional Mortgage Loan [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Unpaid principal balance 66 71
Government-guaranteed or insured mortgage loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Unpaid principal balance $ 6 $ 6
[1] Amortized cost, excluding accrued interest receivable that was not material for the reported periods.