Organization - Organization (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Product Information [Line Items]
On and Off Balance Sheet Program Assets, At Principal Balance	$ 17,399,475	$ 15,898,820	$ 14,597,758
Medium-term Notes [Member]
Product Information [Line Items]
Notes Payable	9,900,000
Discount Notes [Member]
Product Information [Line Items]
Notes Payable	3,800,000
Farm & Ranch [Member]
Product Information [Line Items]
On and Off Balance Sheet Program Assets, At Principal Balance	6,139,304	5,725,299	5,417,174
USDA Guarantees [Member]
Product Information [Line Items]
On and Off Balance Sheet Program Assets, At Principal Balance	2,094,375	1,918,277	1,798,034
Rural Utilities [Member]
Product Information [Line Items]
On and Off Balance Sheet Program Assets, At Principal Balance	1,878,110	1,530,990	985,609
Institutional Credit [Member]
Product Information [Line Items]
On and Off Balance Sheet Program Assets, At Principal Balance	$ 7,287,686	$ 6,724,254	$ 6,396,941