Securitization Activities - Additional Information (Detail) - USD ($) $ in Millions	May. 31, 2015	Nov. 30, 2014
Transfers and Servicing [Abstract]
Carrying value of assets	$ 3.9	$ 7.8
Carrying value of liabilities	$ 3.9	$ 7.8

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