v3.26.3
Financial Guarantees (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Guarantor Obligations [Line Items]    
Outstanding balance of the guarantor advance $ 300 $ 400
Guarantees of Fannie Mae securities    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance 94,144 98,370
Maximum exposure 94,144 98,370
Recognized Liability $ 0 $ 0
Maximum Remaining Term 30 years 36 years
Other Guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 55 $ 64
Maximum exposure 356 399
Recognized Liability $ 0 $ 0
Maximum Remaining Term 29 years 30 years
Single-family    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 35,062 $ 37,237
Maximum exposure 29,940 31,816
Recognized Liability 506 549
Single-family | Securitization products    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance 28,391 30,025
Maximum exposure 23,269 24,604
Recognized Liability $ 430 $ 453
Maximum Remaining Term 39 years 40 years
Single-family | Other mortgage-related guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 6,671 $ 7,212
Maximum exposure 6,671 7,212
Recognized Liability $ 76 $ 96
Maximum Remaining Term 26 years 26 years
Multifamily    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 315,155 $ 342,575
Maximum exposure 285,692 309,499
Recognized Liability 3,357 3,961
Multifamily | Securitization products    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance 305,165 332,572
Maximum exposure 275,714 299,507
Recognized Liability $ 3,051 $ 3,629
Maximum Remaining Term 34 years 34 years
Multifamily | Other mortgage-related guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 9,990 $ 10,003
Maximum exposure 9,978 9,992
Recognized Liability $ 306 $ 332
Maximum Remaining Term 32 years 33 years