Affordable Housing Program Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Affordable Housing Program [Roll Forward]
Balance at beginning of year	$ 83,965	$ 81,600
AHP expense for the period	21,302	24,299	$ 21,307
AHP direct grant disbursements	(15,723)	(17,729)	(18,628)
AHP subsidy for AHP advance disbursements	(3,450)	(4,360)
Return of previously disbursed grants and subsidies	37	155
Balance at end of year	$ 86,131	$ 83,965	$ 81,600
FHLBanks [Member]
Affordable Housing Program [Line Items]
Affordable Housing Program Contribution Requirement, Percent	10.00%
Affordable Housing Program Contribution Requirement, Amount	$ 100,000