Guarantees and Commitments - Unpaid Principal Balances by Delinquency Status (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Guarantor Obligations [Line Items]
Total	$ 8,481,310	$ 8,314,096
Current
Guarantor Obligations [Line Items]
Total	9,349,595	9,104,206
Total Past Due
Guarantor Obligations [Line Items]
Total	13,780	5,116
30-59 Days
Guarantor Obligations [Line Items]
Total	4,624	4,548
60-89 Days
Guarantor Obligations [Line Items]
Total	639	568
90 Days and Greater
Guarantor Obligations [Line Items]
Total	8,517	0
Agricultural Finance
Guarantor Obligations [Line Items]
Total	6,932,229	6,846,993
Agricultural Finance | Current
Guarantor Obligations [Line Items]
Total	6,797,744	6,715,070
Agricultural Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	13,780	5,116
Agricultural Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	4,624	4,548
Agricultural Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	639	568
Agricultural Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	8,517	0
Rural Infrastructure Finance
Guarantor Obligations [Line Items]
Total	2,551,851	2,389,136
Rural Infrastructure Finance | Current
Guarantor Obligations [Line Items]
Total	2,551,851	2,389,136
Rural Infrastructure Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	0	0
Rural Infrastructure Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	0	0
Rural Infrastructure Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	0	0
Rural Infrastructure Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	0	0
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance
Guarantor Obligations [Line Items]
Total	2,947,749	2,964,756
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | Current
Guarantor Obligations [Line Items]
Total	2,942,666	2,953,091
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	5,083	11,665
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	1,578	8,068
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	1,618	0
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	1,887	3,597
LTSPCs | Rural Infrastructure Finance
Guarantor Obligations [Line Items]
Total	562,568	556,837
LTSPCs | Rural Infrastructure Finance | Current
Guarantor Obligations [Line Items]
Total	562,568	556,837
LTSPCs | Rural Infrastructure Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	0	0
LTSPCs | Rural Infrastructure Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	0	0
LTSPCs | Rural Infrastructure Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	0	0
LTSPCs | Rural Infrastructure Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	$ 0	$ 0