The reserve for guarantee losses is a liability account in the consolidated balance sheets that reflects an estimate of incurred credit losses related to the guaranty of unconsolidated trusts and other credit guarantees

No definition available.

+ Details

Name:	agm_ReserveForLosses
Namespace Prefix:	agm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of writeoff of financing receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922352-210448

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense related to credit loss from transactions other than loan and lease transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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- Details

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Guarantees - Reserve For Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Reserve for losses	$ 3,420			$ 2,164
Provision for/(release of) losses	393	$ (129)
Farm & Ranch
Guarantor Obligations [Line Items]
Reserve for losses	2,020	2,038	$ 2,016	2,164	$ 2,167	$ 2,167
Provision for/(release of) losses	4	(129)
Charge-offs	0	0
Rural Utilities
Guarantor Obligations [Line Items]
Reserve for losses	1,400	0	$ 1,011	0	$ 0	$ 0
Provision for/(release of) losses	389	0
Charge-offs	0	$ 0
LTSPCs and Farmer Mac Guaranteed Securities \| Farm & Ranch
Guarantor Obligations [Line Items]
Reserve for losses	2,020			2,164
Charge-offs	0
LTSPCs \| Rural Utilities
Guarantor Obligations [Line Items]
Reserve for losses	1,400			$ 0
Charge-offs	$ 0