Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance of mortgage loans	$ 4,098,304	$ 4,098,304	$ 4,102,632
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance of mortgage loans	470,928	470,928	$ 461,247
Multifamily | Adjustable Rate Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance of mortgage loans	$ 600	$ 600
Loan delinquency period	30 days	30 days