Securitization Activities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	May 31, 2014	Nov. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Carrying value of assets	$ 20.3	$ 8.7
Carrying value of liabilities	$ 20.3	$ 8.7

Carrying Value Of Liabilities Resulting From Transfers

No definition available.

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