Activities with Stockholders (Transactions with Directors' Financial Institutions) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Related Party Transaction [Line Items]
Advances	$ 127,032	$ 110,230
Deposits, Domestic	1,426	1,147
Capital Stock	7,286	6,509
Director [Member]
Related Party Transaction [Line Items]
Advances	$ 414	$ 667
Advances, Percent	0.00%	1.00%
Mortgage Loans, Percent	3.00%	4.00%
Deposits, Domestic	$ 12	$ 15
Deposits, Percent	1.00%	1.00%
Capital Stock	$ 47	$ 65
Capital Stock, Percent	1.00%	1.00%
Director [Member] | Conventional Mortgage Loan [Member]
Related Party Transaction [Line Items]
Financing Receivable, Allowance for Credit Loss, Noncurrent	$ 482	$ 606