v3.26.3
Concentration of Credit and Other Risks - Concentration of Credit Risk - Single-Family Mortgage Portfolio (Details)
$ in Millions
Sep. 30, 2026
USD ($)
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.61%
West  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.48%
Northeast  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.62%
Southeast  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.71%
Southwest  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.67%
North Central  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.61%
California  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.46%
Texas  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.75%
Florida  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.85%
New York  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.81%
Illinois  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.72%
All Other  
Concentration Risk [Line Items]  
Single-Family serious delinquency rate 0.58%
Geographic Concentration Risk | All Other  
Concentration Risk [Line Items]  
Portfolio UPB $ 1,972,001
Concentration risk percentage 62.00%
Geographic Concentration Risk | Single-family UPB  
Concentration Risk [Line Items]  
Portfolio UPB $ 3,185,859
Concentration risk percentage 100.00%
Geographic Concentration Risk | Single-family UPB | West  
Concentration Risk [Line Items]  
Portfolio UPB $ 921,513
Concentration risk percentage 29.00%
Geographic Concentration Risk | Single-family UPB | Northeast  
Concentration Risk [Line Items]  
Portfolio UPB $ 735,571
Concentration risk percentage 23.00%
Geographic Concentration Risk | Single-family UPB | Southeast  
Concentration Risk [Line Items]  
Portfolio UPB $ 572,643
Concentration risk percentage 18.00%
Geographic Concentration Risk | Single-family UPB | Southwest  
Concentration Risk [Line Items]  
Portfolio UPB $ 485,058
Concentration risk percentage 15.00%
Geographic Concentration Risk | Single-family UPB | North Central  
Concentration Risk [Line Items]  
Portfolio UPB $ 471,074
Concentration risk percentage 15.00%
Geographic Concentration Risk | Single-family UPB | California  
Concentration Risk [Line Items]  
Portfolio UPB $ 505,315
Concentration risk percentage 16.00%
Geographic Concentration Risk | Single-family UPB | Texas  
Concentration Risk [Line Items]  
Portfolio UPB $ 232,626
Concentration risk percentage 7.00%
Geographic Concentration Risk | Single-family UPB | Florida  
Concentration Risk [Line Items]  
Portfolio UPB $ 215,690
Concentration risk percentage 7.00%
Geographic Concentration Risk | Single-family UPB | New York  
Concentration Risk [Line Items]  
Portfolio UPB $ 140,516
Concentration risk percentage 4.00%
Geographic Concentration Risk | Single-family UPB | Illinois  
Concentration Risk [Line Items]  
Portfolio UPB $ 119,711
Concentration risk percentage 4.00%