v3.26.1
Mortgage Loans - Amortized Cost Basis of Multifamily Held-for-Investment Loans by Credit Quality Indicator by Vintage (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 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 2 22
Two years before current fiscal Year, year-to-date write-offs 17 44
Three years before current fiscal year, year-to-date write-offs 28 75
Four years before current fiscal year, year-to-date write-offs 37 55
Total 3,303,409 3,291,359
Total current-year gross charge-offs 126 371
Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 8,783 63,205
Current fiscal year, year-to-date write-offs 0 0
One year before current fiscal year 66,632 28,825
Fiscal year before current fiscal year, year-to-date write-offs 0 0
Two years before current fiscal year 28,643 13,813
Two years before current fiscal Year, year-to-date write-offs 0 0
Three years before current fiscal year 13,507 16,490
Three years before current fiscal year, year-to-date write-offs 0 11
Four years before current fiscal year 16,169 7,567
Four years before current fiscal year, year-to-date write-offs 0 0
Five years before current fiscal year 21,432 13,842
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff 50 115
Revolving Loans 1,626 1,851
Financing Receivable, Excluding Accrued Interest, Revolving, Writeoff 0 0
Total 156,792 145,593
Total current-year gross charge-offs 50 126
Pass | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 8,783 63,205
One year before current fiscal year 66,396 28,613
Two years before current fiscal year 28,076 13,374
Three years before current fiscal year 12,949 15,732
Four years before current fiscal year 15,233 7,238
Five years before current fiscal year 20,258 12,947
Revolving Loans 1,626 1,851
Total 153,321 142,960
Special mention | Multifamily    
Financing Receivable, Credit Quality Indicator [Line Items]    
Current fiscal year 0 0
One year before current fiscal year 236 49
Two years before current fiscal year 313 173
Three years before current fiscal year 139 177
Four years before current fiscal year 274 96
Five years before current fiscal year 739 670
Revolving Loans 0 0
Total 1,701 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 254 266
Three years before current fiscal year 419 581
Four years before current fiscal year 662 233
Five years before current fiscal year 435 225
Revolving Loans 0 0
Total 1,770 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