Guarantees and Commitments - Credit Quality Indicators (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Total
Total	$ 8,481,310		$ 8,314,096
Agricultural Finance
Year One
Total	407,133		2,224,509
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Two
Total	2,207,958		1,596,563
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Three
Total	1,537,824		617,576
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Four
Total	571,198		400,104
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Five
Total	372,486		351,687
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Prior
Total	1,295,289		1,095,135
Current period charge-offs	84		0
Current period recoveries	0		0
Current period, net charge offs	84		0
Revolving Loans - Amortized Cost Basis
Total	540,341		561,419
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Total
Total	6,932,229		6,846,993
Charge-off from the allowance for losses	84	$ 0	0
Current period recoveries	0		0
Current period, net charge offs	84		0
Rural Infrastructure Finance
Year One
Total	175,976		242,570
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Two
Total	230,729		635,166
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Three
Total	643,667		774,941
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Four
Total	766,559		8,100
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Five
Total	8,017		86,878
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Prior
Total	695,266		628,903
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Revolving Loans - Amortized Cost Basis
Total	31,637		12,578
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Total
Total	2,551,851		2,389,136
Charge-off from the allowance for losses	0	$ 0	0
Current period recoveries	0		0
Current period, net charge offs	0		0
Acceptable | Agricultural Finance
Year One
Total	400,124		2,138,060
Year Two
Total	2,080,013		1,541,509
Year Three
Total	1,473,300		540,139
Year Four
Total	504,767		324,917
Year Five
Total	306,332		303,852
Prior
Total	1,179,889		1,004,709
Revolving Loans - Amortized Cost Basis
Total	512,678		545,370
Total
Total	6,457,103		6,398,556
Acceptable | Rural Infrastructure Finance
Year One
Total	175,976		242,570
Year Two
Total	230,729		612,366
Year Three
Total	643,667		774,941
Year Four
Total	766,559		8,100
Year Five
Total	8,017		86,878
Prior
Total	695,266		628,903
Revolving Loans - Amortized Cost Basis
Total	31,637		12,578
Total
Total	2,551,851		2,366,336
Special mention | Agricultural Finance
Year One
Total	7,009		84,795
Year Two
Total	123,893		50,057
Year Three
Total	38,473		51,200
Year Four
Total	43,697		48,078
Year Five
Total	45,722		9,132
Prior
Total	25,750		14,646
Revolving Loans - Amortized Cost Basis
Total	9,279		4,771
Total
Total	293,823		262,679
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	0		1,654
Year Two
Total	4,052		4,997
Year Three
Total	26,051		26,237
Year Four
Total	22,734		27,109
Year Five
Total	20,432		38,703
Prior
Total	89,650		75,780
Revolving Loans - Amortized Cost Basis
Total	18,384		11,278
Total
Total	181,303		185,758
Substandard | Rural Infrastructure Finance
Year One
Total	0		0
Year Two
Total	0		22,800
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		22,800
LTSPCs and Farmer Mac Guaranteed Securities | Agricultural Finance
Year One
Total	39,991		376,027
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Two
Total	425,698		544,098
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Three
Total	507,304		245,089
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Four
Total	245,879		200,298
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Year Five
Total	193,559		251,812
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Prior
Total	1,264,636		1,089,305
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Revolving Loans - Amortized Cost Basis
Total	270,682		258,127
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Total
Total	2,947,749		2,964,756
Charge-off from the allowance for losses	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
LTSPCs and Farmer Mac Guaranteed Securities | Acceptable | Agricultural Finance
Year One
Total	39,991		376,027
Year Two
Total	425,698		537,521
Year Three
Total	504,636		244,365
Year Four
Total	245,154		188,452
Year Five
Total	182,019		235,865
Prior
Total	1,192,160		1,013,937
Revolving Loans - Amortized Cost Basis
Total	264,675		252,039
Total
Total	2,854,333		2,848,206
LTSPCs and Farmer Mac Guaranteed Securities | Special mention | Agricultural Finance
Year One
Total	0		0
Year Two
Total	0		5,270
Year Three
Total	2,470		0
Year Four
Total	0		6,808
Year Five
Total	6,663		3,154
Prior
Total	47,438		38,042
Revolving Loans - Amortized Cost Basis
Total	2,329		2,354
Total
Total	58,900		55,628
LTSPCs and Farmer Mac Guaranteed Securities | Substandard | Agricultural Finance
Year One
Total	0		0
Year Two
Total	0		1,307
Year Three
Total	198		724
Year Four
Total	725		5,038
Year Five
Total	4,877		12,793
Prior
Total	25,038		37,326
Revolving Loans - Amortized Cost Basis
Total	3,678		3,734
Total
Total	34,516		60,922
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	489,384		499,594
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Revolving Loans - Amortized Cost Basis
Total	73,184		57,243
Current period charge-offs	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
Total
Total	562,568		556,837
Charge-off from the allowance for losses	0		0
Current period recoveries	0		0
Current period, net charge offs	0		0
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	489,384		499,594
Revolving Loans - Amortized Cost Basis
Total	73,184		57,243
Total
Total	562,568		556,837
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