v3.10.0.1
DEI Document - shares
9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Document Information [Abstract]    
Entity Registrant Name NuStar Energy L.P.  
Entity Central Index Key 0001110805  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Trading Symbol ns  
Amendment Flag false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Partnership Units Outstanding   107,045,436