Schedule I - Condensed Financial Information of Registrant - Restricted Net Assets (Details) - USD ($) $ in Millions	Nov. 30, 2020	Nov. 30, 2019
Registration Payment Arrangement [Line Items]
Undistributed earnings of unconsolidated subsidiaries	$ 161.0
Parent company
Registration Payment Arrangement [Line Items]
Assets that may be restricted to the payment of cash dividends and advances	6,500.0	$ 5,700.0
Undistributed earnings of unconsolidated subsidiaries	161.0
Restricted assets due to regulatory requirements or regulatory approvals \| Parent company
Registration Payment Arrangement [Line Items]
Assets that may be restricted to the payment of cash dividends and advances	$ 5,700.0	$ 4,900.0

Amount of restricted net assets of consolidated and unconsolidated subsidiaries as of the end of the most recently completed fiscal year.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e)(3)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Name:	us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_RegistrationPaymentArrangementLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50% or less owned persons accounted for by the equity method (equity method investees).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6462270&loc=d3e57205-112772

+ Details

Name:	us-gaap_RetainedEarningsUndistributedEarningsFromEquityMethodInvestees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=jef_RestrictedAssetsduetoregulatoryrequirementsorregulatoryapprovalsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: