Capital Requirements (Details) $ in Thousands	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Capital [Abstract]
Capital-to-asset ratio, Required	4.00%	4.00%
Leverage capital-to-assets ratio, Required	5.00%	5.00%
Multiplier for Determining Permanent Capital in Leverage Capital Calculation	1.5
Class B capital stock	$ 2,266,329	$ 1,869,130
Mandatorily redeemable capital stock	6,112	5,806
Retained earnings	1,473,149	1,463,154
Total permanent capital	3,745,590	3,338,090
Credit-risk capital	212,510	235,213
Market-risk capital	155,678	207,426
Operations-risk capital	110,456	132,792
Total risk-based capital requirement	478,644	575,431
Permanent capital in excess of risk-based capital requirement	3,266,946	2,762,659
Risk-based capital, Actual	3,745,590	3,338,090
Regulatory capital, Required	2,756,035	2,226,512
Regulatory capital, Actual	$ 3,745,590	$ 3,338,090
Capital-to-asset ratio, Actual	5.40%	6.00%
Leverage capital, Actual	$ 5,618,385	$ 5,007,135
Leverage capital, Required	$ 3,445,043	$ 2,783,141
Leverage capital-to-assets ratio, Actual	8.20%	9.00%