Fair Value Disclosures - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
Jul. 01, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Net Income	Net Income	Net Income	Net Income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]		Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 7,770,126	$ 7,770,126	$ 6,477,184	$ 7,632,487	$ 6,358,451
Purchases		100,000	1,370,000	1,639,650	2,722,750
Settlements		(7,172)	(628,211)	(1,407,702)	(1,440,110)
Allowance for Losses		134	0	179	(331)
Realized and unrealized (losses)/gains included in Income		(106,203)	(205,206)	(114,431)	(565,190)
Unrealized gains/(losses) included in Other Comprehensive Income		12,206	(13,979)	18,908	(75,782)
Transfers Out		(2,684,096)		(2,684,096)
Ending Balance		5,084,995	6,999,788	5,084,995	6,999,788
Floating rate auction-rate certificates backed by Government guaranteed student loans \| Floating Interest Rate \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,032	19,032	19,061	19,027	19,254
Purchases		0	0	0	0
Settlements		0	0	0	0
Allowance for Losses		1	11	6	14
Realized and unrealized (losses)/gains included in Income		0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income		0	171	0	(25)
Transfers Out		0		0
Ending Balance		19,033	19,243	19,033	19,243
Available-for-sale securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,032	19,032	19,061	19,027	19,254
Purchases		0	0	0	0
Settlements		0	0	0	0
Allowance for Losses		1	11	6	14
Realized and unrealized (losses)/gains included in Income		0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income		0	171	0	(25)
Transfers Out		0		0
Ending Balance		19,033	19,243	19,033	19,243
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,745,415	7,745,415	6,450,212	7,607,226	6,328,559
Purchases		100,000	1,370,000	1,639,650	2,722,750
Settlements		(7,044)	(627,599)	(1,406,717)	(1,436,963)
Allowance for Losses		133	(11)	173	(345)
Realized and unrealized (losses)/gains included in Income		(107,917)	(204,450)	(116,447)	(564,242)
Unrealized gains/(losses) included in Other Comprehensive Income		12,206	(14,150)	18,908	(75,757)
Transfers Out		(2,684,096)		(2,684,096)
Ending Balance		5,058,697	6,974,002	5,058,697	6,974,002
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| AgVantage Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,737,810	7,737,810	6,440,396	7,599,379	6,316,145
Purchases		100,000	1,370,000	1,639,650	2,722,750
Settlements		(6,875)	(627,131)	(1,405,674)	(1,435,758)
Allowance for Losses		133	(11)	173	(345)
Realized and unrealized (losses)/gains included in Income		(107,917)	(204,450)	(116,447)	(564,242)
Unrealized gains/(losses) included in Other Comprehensive Income		9,653	(13,043)	15,723	(72,789)
Transfers Out	(2,700,000)	(2,684,096)		(2,684,096)
Ending Balance		5,048,708	6,965,761	5,048,708	6,965,761
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,605	7,605	9,816	7,847	12,414
Purchases		0	0	0	0
Settlements		(169)	(468)	(1,043)	(1,205)
Allowance for Losses		0	0	0	0
Realized and unrealized (losses)/gains included in Income		0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income		2,553	(1,107)	3,185	(2,968)
Transfers Out		0		0
Ending Balance		9,989	8,241	9,989	8,241
USDA Securities: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,348	1,348	2,275	1,767	4,401
Purchases		0	0	0	0
Settlements		(44)	(383)	(479)	(2,475)
Allowance for Losses		0	0	0	0
Realized and unrealized (losses)/gains included in Income		(2)	(41)	14	(75)
Unrealized gains/(losses) included in Other Comprehensive Income		0	0	0	0
Transfers Out		0		0
Ending Balance		1,302	1,851	1,302	1,851
Guarantee and commitment obligations: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,331	4,331	5,636	4,467	6,237
Purchases		0	0	0	0
Settlements		(84)	(229)	(506)	(672)
Allowance for Losses		0	0	0	0
Realized and unrealized (losses)/gains included in Income		1,716	(715)	2,002	(873)
Unrealized gains/(losses) included in Other Comprehensive Income		0	0	0	0
Transfers Out		0		0
Ending Balance		5,963	4,692	5,963	4,692
Guarantee and commitment obligations: \| Level 3 \| Recurring \| Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 4,331	4,331	5,636	4,467	6,237
Purchases		0	0	0	0
Settlements		(84)	(229)	(506)	(672)
Allowance for Losses		0	0	0	0
Realized and unrealized (losses)/gains included in Income		1,716	(715)	2,002	(873)
Unrealized gains/(losses) included in Other Comprehensive Income		0	0	0	0
Transfers Out		0		0
Ending Balance		$ 5,963	$ 4,692	$ 5,963	$ 4,692

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Allowance for Credit Loss

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

+ References

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-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-SubTopic 10
-Topic 820
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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Indicates line item in statement in which other comprehensive income (OCI) is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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