v3.3.1.900
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2015
Feb. 24, 2016
Jun. 30, 2015
Document and Entity Information [Abstract]      
Entity Registrant Name MEDICINES CO /DE    
Entity Central Index Key 0001113481    
Document Type 10-K    
Document Period End Date Dec. 31, 2015    
Amendment Flag false    
Document Fiscal Year Focus 2015    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 1,907,787,469
Entity Common Stock, Shares Outstanding   69,615,054