v3.8.0.1
DEI Document - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Jan. 31, 2018
Jun. 30, 2017
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-K    
Document Period End Date Dec. 31, 2017    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
Trading Symbol ns    
Amendment Flag false    
Entity Partnership Units Outstanding   93,182,018  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 3,692