Cover - USD ($)	12 Months Ended
	Nov. 30, 2021	May 31, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Nov. 30, 2021
Current Fiscal Year End Date	--11-30
Document Transition Report	false
Entity File Number	1-14947
Entity Registrant Name	JEFFERIES GROUP LLC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-4719745
Entity Address, Address Line One	520 Madison Avenue,
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10022
City Area Code	212
Local Phone Number	284-2550
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float		$ 0
Entity Central Index Key	0001084580
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding	0
4.850% Senior notes
Entity Information [Line Items]
Title of 12(b) Security	4.850% Senior Notes Due 2027
Trading Symbol	JEF/27A
Security Exchange Name	NYSE
2.750% Senior Notes
Entity Information [Line Items]
Title of 12(b) Security	2.750% Senior Notes Due 2032
Trading Symbol	JEF/32A
Security Exchange Name	NYSE