Consolidated Obligations (Bonds by Maturity or Call Date) (Details) - Consolidated Obligation Bonds [Member] - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Bonds, Due in one year or less	$ 56,814	$ 55,386
Bonds, Due after one year through two years	7,072	13,292
Bonds, Due after two years through three years	3,704	3,387
Bonds, Due after three years through four years	3,804	3,884
Bonds, Due after four years through five years	2,295	1,429
Bonds, Due after five years	1,768	1,888
Bonds par value	75,457	79,266
Earlier of Contractual Maturity or Next Call Date [Member]
Debt Instrument [Line Items]
Bonds, Due in one year or less	65,979	65,560
Bonds, Due after one year through two years	5,478	10,874
Bonds, Due after two years through three years	1,149	982
Bonds, Due after three years through four years	309	429
Bonds, Due after four years through five years	1,289	168
Bonds, Due after five years	$ 1,253	$ 1,253