v3.26.1
Mortgage Loans - Subsequent Defaults of Single-Family Restructured Loans Involving Borrowers Experiencing Financial Difficulty (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Single family    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default $ 2,210 $ 1,637
Single family | payment delay [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 1,091 1,021
Single family | payment delay and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 983 607
Single family | payment delay, interest rate reduction, and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 136 9
20- and 30-year or more, amortizing fixed-rate    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 2,174 1,590
20- and 30-year or more, amortizing fixed-rate | payment delay [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 1,056 975
20- and 30-year or more, amortizing fixed-rate | payment delay and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 982 606
20- and 30-year or more, amortizing fixed-rate | payment delay, interest rate reduction, and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 136 9
15-year or less, amortizing fixed-rate    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 24 35
15-year or less, amortizing fixed-rate | payment delay [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 24 35
15-year or less, amortizing fixed-rate | payment delay and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 0 0
15-year or less, amortizing fixed-rate | payment delay, interest rate reduction, and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 0 0
Adjustable-rate and other    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 12 12
Adjustable-rate and other | payment delay [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 11 11
Adjustable-rate and other | payment delay and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default 1 1
Adjustable-rate and other | payment delay, interest rate reduction, and term extension [Member]    
financing receivable, loan restructuring [Line Items]    
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default $ 0 $ 0