Derivative Financial Instruments (Unrealized and Realized Gains (Losses) on Derivative Contracts (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in Interest expense of Jefferies Group	$ (302)	$ (1,009)	$ (704)	$ (1,978)
Unrealized and realized gains (losses)	62,231	(97,982)	214,132	(211,648)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	(4,079)	(34,020)	(5,168)	(103,851)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	437	2,284	(1,884)	2,108
Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	9,147	(92,109)	146,035	(120,590)
Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	44,172	21,045	60,765	1,772
Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	12,554	4,818	14,384	8,913
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in Interest expense of Jefferies Group	22,004	27,204	46,469	41,791
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in Interest expense of Jefferies Group	$ (22,306)	$ (28,213)	$ (47,173)	$ (43,769)

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.

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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