Mortgage Loans - Loan Restructuring - Financial Impacts (Details) - Single-family	3 Months Ended		9 Months Ended
	Sep. 30, 2026 USD ($) mo	Sep. 30, 2025 USD ($) mo	Sep. 30, 2026 USD ($) mo	Sep. 30, 2025 USD ($) mo
20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Weighted-Average Interest Rate Reduction	0.83%	0.54%	0.77%	0.58%
Weighted-Average Term Extension (in Months) | mo	144	142	144	148
Average Amount Capitalized as a Result of a Payment Delay | $	$ 14,493	$ 13,469	$ 14,114	$ 13,162
15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Weighted-Average Interest Rate Reduction	0.69%	0.87%	0.84%	1.02%
Weighted-Average Term Extension (in Months) | mo	52	50	53	51
Average Amount Capitalized as a Result of a Payment Delay | $	$ 11,300	$ 10,061	$ 11,062	$ 9,642
Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Weighted-Average Interest Rate Reduction	0.23%	1.19%	0.54%	1.09%
Weighted-Average Term Extension (in Months) | mo			0	0
Average Amount Capitalized as a Result of a Payment Delay | $	$ 8,630	$ 9,970	$ 11,010	$ 10,115
Other
Loans in Mortgage Portfolio [Line Items]
Weighted-Average Interest Rate Reduction	0.53%	0.67%	1.09%	1.05%
Weighted-Average Term Extension (in Months) | mo	125	131	138	150
Average Amount Capitalized as a Result of a Payment Delay | $	$ 10,724	$ 14,735	$ 13,855	$ 13,571