Statements of Condition (Parenthetical) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Amortized Cost	$ 16,282	$ 16,603
Held-to-Maturity Securities, Fair Value	$ 2,346	$ 2,439
Capital Stock - Class B Putable, Par Value	$ 100	$ 100
Common Class B [Member]
Capital Stock - Class B Putable, Par Value	$ 100	$ 100
Capital Stock - Class B Putable, Issued Shares	47	45
Capital Stock - Class B Putable, Outstanding Shares	47	45
Loans [Member]
Financing Receivable, Allowance for Credit Loss	$ 1	$ 1