v3.19.1
DEI Document - shares
3 Months Ended
Mar. 31, 2019
Apr. 30, 2019
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 Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Trading Symbol ns  
Amendment Flag false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Partnership Units Outstanding   107,763,005