Advances (Earlier of Contractual Maturity or Next Call/Put Date) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Call Date, Rolling Year, Par Value [Abstract]
Within 1 year	$ 39,075	$ 46,740
After 1 year through 2 years	15,731	14,762
After 2 years through 3 years	4,800	5,688
After 3 years through 4 years	2,895	2,409
After 4 years through 5 years	1,447	2,812
After 5 years	1,140	1,084
Federal Home Loan Bank, Advances, Earlier of Contractual Maturity or Next Put or Convert Date, Rolling Year, Par Value [Abstract]
Within 1 year	32,371	42,295
After 1 year through 2 years	22,380	13,672
After 2 years through 3 years	4,847	11,238
After 3 years through 4 years	2,909	2,409
After 4 years through 5 years	1,461	2,815
After 5 years	1,120	1,066
Total par value	$ 65,088	$ 73,495