v3.25.3
Concentration of Credit and Other Risks - Concentration of Credit Risk - Single-Family Mortgage Portfolio (Details)
$ in Millions
Sep. 30, 2025
USD ($)
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.57%
West  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.44%
Northeast  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.59%
Southeast  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.64%
Southwest  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.60%
North Central  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.57%
California  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.44%
Texas  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.67%
Florida  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.78%
New York  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.83%
Illinois  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.69%
All Other  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.53%
Geographic Concentration Risk | All Other  
Concentration Risk [Line Items]  
Portfolio UPB $ 1,934,235
Concentration risk percentage 62.00%
Geographic Concentration Risk | Single-family UPB  
Concentration Risk [Line Items]  
Portfolio UPB $ 3,141,003
Concentration risk percentage 100.00%
Geographic Concentration Risk | Single-family UPB | West  
Concentration Risk [Line Items]  
Portfolio UPB $ 920,864
Concentration risk percentage 29.00%
Geographic Concentration Risk | Single-family UPB | Northeast  
Concentration Risk [Line Items]  
Portfolio UPB $ 725,192
Concentration risk percentage 23.00%
Geographic Concentration Risk | Single-family UPB | Southeast  
Concentration Risk [Line Items]  
Portfolio UPB $ 560,111
Concentration risk percentage 18.00%
Geographic Concentration Risk | Single-family UPB | Southwest  
Concentration Risk [Line Items]  
Portfolio UPB $ 474,951
Concentration risk percentage 15.00%
Geographic Concentration Risk | Single-family UPB | North Central  
Concentration Risk [Line Items]  
Portfolio UPB $ 459,885
Concentration risk percentage 15.00%
Geographic Concentration Risk | Single-family UPB | California  
Concentration Risk [Line Items]  
Portfolio UPB $ 511,341
Concentration risk percentage 16.00%
Geographic Concentration Risk | Single-family UPB | Texas  
Concentration Risk [Line Items]  
Portfolio UPB $ 227,931
Concentration risk percentage 7.00%
Geographic Concentration Risk | Single-family UPB | Florida  
Concentration Risk [Line Items]  
Portfolio UPB $ 212,506
Concentration risk percentage 7.00%
Geographic Concentration Risk | Single-family UPB | New York  
Concentration Risk [Line Items]  
Portfolio UPB $ 137,394
Concentration risk percentage 4.00%
Geographic Concentration Risk | Single-family UPB | Illinois  
Concentration Risk [Line Items]  
Portfolio UPB $ 117,596
Concentration risk percentage 4.00%