Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance of mortgage loans			$ 4,095,019	$ 4,110,196
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance of mortgage loans			$ 501,559	$ 490,358
Multifamily | Adjustable Rate Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loan delinquency period	30 days	30 days
Total unpaid principal balance of mortgage loans	$ 600	$ 600