Commitments, Contingencies and Guarantees - Guarantees (Detail) $ in Millions	Nov. 30, 2015 USD ($)
Guarantee Obligations [Line Items]
Notional/ Maximum Payout	$ 5,582.2
Derivative contracts - non-credit related [Member]
Guarantee Obligations [Line Items]
2016	11,840.6
2017	584.6
2018 and 2019	142.8
2020 and 2021	0.0
2022 and Later	414.4
Notional/ Maximum Payout	12,982.4
Written derivative contracts - credit related [Member]
Guarantee Obligations [Line Items]
2016	0.0
2017	0.0
2018 and 2019	115.4
2020 and 2021	955.4
2022 and Later	10.0
Notional/ Maximum Payout	1,080.8
Derivatives [Member]
Guarantee Obligations [Line Items]
2016	11,840.6
2017	584.6
2018 and 2019	258.2
2020 and 2021	955.4
2022 and Later	424.4
Notional/ Maximum Payout	$ 14,063.2

Guarantees with a remaining term that matures during the fiscal year. These may include derivative guarantees, etc.

No definition available.

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Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Guarantees expected to be due within 5 to 6 fiscal years. These may include, derivative guarantees, etc.

+ References

No definition available.

+ Details

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Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Guarantees expected to be due within 3 to 4 fiscal years. These may include, derivative guarantees, etc.

+ References

No definition available.

+ Details

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Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Guarantees expected to be due within 2 fiscal years. These may include, derivative guarantees, etc.

+ References

No definition available.

+ Details

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Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Guarantees expected to be due within 7 fiscal years and thereafter. These may include, derivative guarantees, etc

+ References

No definition available.

+ Details

Name:	jef_GuaranteesExpectedToBeDueThereafter
Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=jef_DerivativeContractsCreditRelatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_DerivativeMember
Namespace Prefix:
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Balance Type:
Period Type: