v3.26.3
Mortgage Loans - Amortized Cost Basis of Multifamily Held-for-Investment Loans by Credit Quality Indicator by Vintage (Details) - USD ($)
$ in Millions
 9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year, year-to-date write-offs $ 0 $ 1
Fiscal year before current fiscal year, year-to-date write-offs 16 22
Two years before current fiscal Year, year-to-date write-offs 80 44
Three years before current fiscal year, year-to-date write-offs 116 75
Four years before current fiscal year, year-to-date write-offs 126 55
Total 3,356,923 3,291,359
Total current-year gross charge-offs 447 371
Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 41,124 63,205
Current fiscal year, year-to-date write-offs 0 0
One year before current fiscal year 66,795 28,825
Fiscal year before current fiscal year, year-to-date write-offs 0 0
Two years before current fiscal year 28,510 13,813
Two years before current fiscal Year, year-to-date write-offs 0 0
Three years before current fiscal year 13,119 16,490
Three years before current fiscal year, year-to-date write-offs 5 11
Four years before current fiscal year 15,864 7,567
Four years before current fiscal year, year-to-date write-offs 3 0
Five years before current fiscal year 20,124 13,842
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff 54 115
Revolving Loans 1,257 1,851
Financing Receivable, Excluding Accrued Interest, Revolving, Writeoff 0 0
Total 186,793 145,593
Total current-year gross charge-offs 62 126
Pass | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 41,124 63,205
One year before current fiscal year 66,673 28,613
Two years before current fiscal year 27,774 13,374
Three years before current fiscal year 12,337 15,732
Four years before current fiscal year 14,761 7,238
Five years before current fiscal year 18,996 12,947
Revolving Loans 1,257 1,851
Total 182,922 142,960
Special mention | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 0 0
One year before current fiscal year 122 49
Two years before current fiscal year 196 173
Three years before current fiscal year 41 177
Four years before current fiscal year 133 96
Five years before current fiscal year 537 670
Revolving Loans 0 0
Total 1,029 1,165
Substandard | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 0 0
One year before current fiscal year 0 163
Two years before current fiscal year 540 266
Three years before current fiscal year 741 581
Four years before current fiscal year 970 233
Five years before current fiscal year 591 225
Revolving Loans 0 0
Total 2,842 1,468
Doubtful | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 0 0
One year before current fiscal year 0 0
Two years before current fiscal year 0 0
Three years before current fiscal year 0 0
Four years before current fiscal year 0 0
Five years before current fiscal year 0 0
Revolving Loans 0 0
Total $ 0 $ 0