Document And Entity Information	9 Months Ended
	Sep. 28, 2013	Oct. 26, 2013 Common Class A [Member]	Oct. 26, 2013 Common Class B [Member]
Document Information [Line Items]
Entity Registrant Name	U. S. Premium Beef, LLC
Entity Central Index Key	0001289237
Current Fiscal Year End Date	--12-29
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		735,385	755,385
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 28, 2013
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2013