Guarantees and Commitments - Unpaid Principal Balances by Delinquency Status (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Guarantor Obligations [Line Items]
Total	$ 8,314,096	$ 7,261,933
Current
Guarantor Obligations [Line Items]
Total	9,104,206	8,315,566
Total Past Due
Guarantor Obligations [Line Items]
Total	5,116	6,286
30-59 Days
Guarantor Obligations [Line Items]
Total	4,548	4,582
60-89 Days
Guarantor Obligations [Line Items]
Total	568	632
90 Days and Greater
Guarantor Obligations [Line Items]
Total	0	1,072
Agricultural Finance
Guarantor Obligations [Line Items]
Total	6,846,993	6,176,438
Agricultural Finance | Current
Guarantor Obligations [Line Items]
Total	6,715,070	6,055,154
Agricultural Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	5,116	6,286
Agricultural Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	4,548	4,582
Agricultural Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	568	632
Agricultural Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	0	1,072
Rural Infrastructure Finance
Guarantor Obligations [Line Items]
Total	2,389,136	2,260,412
Rural Infrastructure Finance | Current
Guarantor Obligations [Line Items]
Total	2,389,136	2,260,412
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	2,964,756	2,404,743
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | Current
Guarantor Obligations [Line Items]
Total	2,953,091	2,389,777
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | Total Past Due
Guarantor Obligations [Line Items]
Total	11,665	14,966
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 30-59 Days
Guarantor Obligations [Line Items]
Total	8,068	2,189
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 60-89 Days
Guarantor Obligations [Line Items]
Total	0	1,344
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance | 90 Days and Greater
Guarantor Obligations [Line Items]
Total	3,597	11,433
LTSPCs | Rural Infrastructure Finance
Guarantor Obligations [Line Items]
Total	556,837	556,425
LTSPCs | Rural Infrastructure Finance | Current
Guarantor Obligations [Line Items]
Total	556,837	556,425
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