v3.26.1
Financial Guarantees (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Jun. 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 95,575 98,370
Maximum exposure 95,575 98,370
Recognized Liability $ 0 $ 0
Maximum Remaining Term 35 years 36 years
Other Guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 59 $ 64
Maximum exposure 368 399
Recognized Liability $ 0 $ 0
Maximum Remaining Term 29 years 30 years
Single-family    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 35,797 $ 37,237
Maximum exposure 30,592 31,816
Recognized Liability 520 549
Single-family | Securitization products    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance 28,936 30,025
Maximum exposure 23,731 24,604
Recognized Liability $ 438 $ 453
Maximum Remaining Term 39 years 40 years
Single-family | Other mortgage-related guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 6,861 $ 7,212
Maximum exposure 6,861 7,212
Recognized Liability $ 82 $ 96
Maximum Remaining Term 26 years 26 years
Multifamily    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 324,383 $ 342,575
Maximum exposure 293,742 309,499
Recognized Liability 3,532 3,961
Multifamily | Securitization products    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance 314,464 332,572
Maximum exposure 283,834 299,507
Recognized Liability $ 3,221 $ 3,629
Maximum Remaining Term 34 years 34 years
Multifamily | Other mortgage-related guarantees    
Guarantor Obligations [Line Items]    
Unpaid Principal Balance $ 9,919 $ 10,003
Maximum exposure 9,908 9,992
Recognized Liability $ 311 $ 332
Maximum Remaining Term 32 years 33 years