Guarantees and Commitments - Credit Quality Indicators (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Total
(Recovery)/charge-off from the allowance for losses		$ 5,800
Total	$ 8,314,096	7,261,933
Agricultural Finance
Year One
Total	2,224,509	2,021,189
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Two
Total	1,596,563	859,880
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Three
Total	617,576	524,541
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Four
Total	400,104	562,007
Current period charge-offs	0	5,365
Current period recoveries	0	0
Current period, net charge offs	0	5,365
Year Five
Total	351,687	515,561
Current period charge-offs	0	0
Current period recoveries	(1,054)	0
Current period, net charge offs	(1,054)	0
Prior
Total	1,095,135	1,140,603
Current period charge-offs	0	394
Current period recoveries	0	0
Current period, net charge offs	0	394
Revolving Loans - Amortized Cost Basis
Total	561,419	552,657
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total
(Recovery)/charge-off from the allowance for losses	0	5,759	$ 67
Current period recoveries	(1,054)	0
Current period, net charge offs	(1,054)	5,759
Total	6,846,993	6,176,438
Rural Infrastructure Finance
Year One
Total	242,570	667,489
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Two
Total	635,166	809,921
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Three
Total	774,941	8,260
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Four
Total	8,100	89,842
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Five
Total	86,878	31,275
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Prior
Total	628,903	641,145
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Revolving Loans - Amortized Cost Basis
Total	12,578	12,480
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total
(Recovery)/charge-off from the allowance for losses	0	0	$ 0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total	2,389,136	2,260,412
Acceptable | Agricultural Finance
Year One
Total	2,138,060	1,947,618
Year Two
Total	1,541,509	774,315
Year Three
Total	540,139	484,345
Year Four
Total	324,917	500,768
Year Five
Total	303,852	465,277
Prior
Total	1,004,709	1,068,693
Revolving Loans - Amortized Cost Basis
Total	545,370	535,742
Total
Total	6,398,556	5,776,758
Acceptable | Rural Infrastructure Finance
Year One
Total	242,570	667,489
Year Two
Total	612,366	809,921
Year Three
Total	774,941	8,260
Year Four
Total	8,100	89,842
Year Five
Total	86,878	31,275
Prior
Total	628,903	641,145
Revolving Loans - Amortized Cost Basis
Total	12,578	12,480
Total
Total	2,366,336	2,260,412
Special mention | Agricultural Finance
Year One
Total	84,795	70,171
Year Two
Total	50,057	79,744
Year Three
Total	51,200	18,317
Year Four
Total	48,078	8,530
Year Five
Total	9,132	13,111
Prior
Total	14,646	21,328
Revolving Loans - Amortized Cost Basis
Total	4,771	7,656
Total
Total	262,679	218,857
Special mention | Rural Infrastructure Finance
Year One
Total	0	0
Year Two
Total	0	0
Year Three
Total	0	0
Year Four
Total	0	0
Year Five
Total	0	0
Prior
Total	0	0
Revolving Loans - Amortized Cost Basis
Total	0	0
Total
Total	0	0
Substandard | Agricultural Finance
Year One
Total	1,654	3,400
Year Two
Total	4,997	5,821
Year Three
Total	26,237	21,879
Year Four
Total	27,109	52,709
Year Five
Total	38,703	37,173
Prior
Total	75,780	50,582
Revolving Loans - Amortized Cost Basis
Total	11,278	9,259
Total
Total	185,758	180,823
Substandard | Rural Infrastructure Finance
Year One
Total	0	0
Year Two
Total	22,800	0
Year Three
Total	0	0
Year Four
Total	0	0
Year Five
Total	0	0
Prior
Total	0	0
Revolving Loans - Amortized Cost Basis
Total	0	0
Total
Total	22,800	0
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance
Year One
Total	376,027	182,397
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Two
Total	544,098	225,612
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Three
Total	245,089	198,061
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Four
Total	200,298	257,223
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Five
Total	251,812	234,781
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Prior
Total	1,089,305	1,080,466
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Revolving Loans - Amortized Cost Basis
Total	258,127	226,203
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total
(Recovery)/charge-off from the allowance for losses	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total	2,964,756	2,404,743
LTSPCs and Farmer Mac Guaranteed Securities | Acceptable | Agricultural Finance
Year One
Total	376,027	178,213
Year Two
Total	537,521	213,620
Year Three
Total	244,365	183,948
Year Four
Total	188,452	237,042
Year Five
Total	235,865	207,296
Prior
Total	1,013,937	969,860
Revolving Loans - Amortized Cost Basis
Total	252,039	211,620
Total
Total	2,848,206	2,201,599
LTSPCs and Farmer Mac Guaranteed Securities | Special mention | Agricultural Finance
Year One
Total	0	3,920
Year Two
Total	5,270	1,742
Year Three
Total	0	1,502
Year Four
Total	6,808	5,603
Year Five
Total	3,154	19,644
Prior
Total	38,042	50,004
Revolving Loans - Amortized Cost Basis
Total	2,354	10,058
Total
Total	55,628	92,473
LTSPCs and Farmer Mac Guaranteed Securities | Substandard | Agricultural Finance
Year One
Total	0	264
Year Two
Total	1,307	10,250
Year Three
Total	724	12,611
Year Four
Total	5,038	14,578
Year Five
Total	12,793	7,841
Prior
Total	37,326	60,602
Revolving Loans - Amortized Cost Basis
Total	3,734	4,525
Total
Total	60,922	110,671
LTSPCs | Rural Infrastructure Finance
Year One
Total	0	0
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Two
Total	0	0
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Three
Total	0	0
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Four
Total	0	0
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Year Five
Total	0	0
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Prior
Total	499,594	549,405
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Revolving Loans - Amortized Cost Basis
Total	57,243	7,020
Current period charge-offs	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total
(Recovery)/charge-off from the allowance for losses	0	0
Current period recoveries	0	0
Current period, net charge offs	0	0
Total	556,837	556,425
LTSPCs | Acceptable | Rural Infrastructure Finance
Year One
Total	0	0
Year Two
Total	0	0
Year Three
Total	0	0
Year Four
Total	0	0
Year Five
Total	0	0
Prior
Total	499,594	549,405
Revolving Loans - Amortized Cost Basis
Total	57,243	7,020
Total
Total	556,837	556,425
LTSPCs | Special mention | Rural Infrastructure Finance
Year One
Total	0	0
Year Two
Total	0	0
Year Three
Total	0	0
Year Four
Total	0	0
Year Five
Total	0	0
Prior
Total	0	0
Revolving Loans - Amortized Cost Basis
Total	0	0
Total
Total	0	0
LTSPCs | Substandard | Rural Infrastructure Finance
Year One
Total	0	0
Year Two
Total	0	0
Year Three
Total	0	0
Year Four
Total	0	0
Year Five
Total	0	0
Prior
Total	0	0
Revolving Loans - Amortized Cost Basis
Total	0	0
Total
Total	$ 0	$ 0