Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) $ in Millions	3 Months Ended
Feb. 28, 2017 USD ($)
Statement of Comprehensive Income [Abstract]
Changes in instrument specific credit risk, tax benefit	$ 6.3

Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Tax

No definition available.

Name:	jef_OtherComprehensiveIncomeLossChangesinInstrumentSpecificCreditRiskTax
Namespace Prefix:	jef_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration