Commitments, Contingencies and Guarantees - Guarantees (Detail) (USD $) In Millions, unless otherwise specified	Feb. 28, 2015
Guarantee Obligations [Line Items]
Notional/Maximum Payout	$ 5,537.0
Derivative contracts - non-credit related [Member]
Guarantee Obligations [Line Items]
2015	37,182.4
2016	2,241.6
2017 and 2018	561.4
2019 and 2020	699.1
2021 and Later	438.9
Notional/Maximum Payout	41,123.4
Written derivative contracts - credit related [Member]
Guarantee Obligations [Line Items]
2015	2.0
2016	0
2017 and 2018	0
2019 and 2020	2,762.2
2021 and Later	84.0
Notional/Maximum Payout	2,848.2
Derivatives [Member]
Guarantee Obligations [Line Items]
2015	37,184.4
2016	2,241.6
2017 and 2018	561.4
2019 and 2020	3,461.3
2021 and Later	522.9
Notional/Maximum Payout	$ 43,971.6

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

No definition available.

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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

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

- Details

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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

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Data Type:	na
Balance Type:
Period Type:

- Details

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Period Type: