Commitments, Contingencies and Guarantees - Guarantees (Detail) (USD $) In Millions, unless otherwise specified	Feb. 28, 2014
Guarantee Obligations [Line Items]
Notional/ Maximum Payout	$ 2,709.7
Derivative contracts - non-credit related [Member]
Guarantee Obligations [Line Items]
2014	46,801.9
2015	708.0
2016 and 2017	15.2
2018 and 2019	1.2
2020 and Later	541.7
Notional/ Maximum Payout	48,068.0
Written derivative contracts - credit related [Member]
Guarantee Obligations [Line Items]
2014	0
2015	5.0
2016 and 2017	0
2018 and 2019	376.0
2020 and Later	5.0
Notional/ Maximum Payout	386.0
Derivatives [Member]
Guarantee Obligations [Line Items]
2014	46,801.9
2015	713.0
2016 and 2017	15.2
2018 and 2019	377.2
2020 and Later	546.7
Notional/ Maximum Payout	$ 48,454.0

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

No definition available.

Name:	jef_GuaranteesExpectedToBeDueCurrent
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

Name:	jef_GuaranteesExpectedToBeDueInFiveAndSixYears
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

Name:	jef_GuaranteesExpectedToBeDueInThreeAndFourYears
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

Name:	jef_GuaranteesExpectedToBeDueInTwoYears
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

- 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 FASB Interpretation (FIN)

-Number 45

-Paragraph 13

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant