Document and Entity Information (USD $)
 12 Months Ended
Oct. 31, 2011
Apr. 30, 2011
Document and Entity Information    
Entity registrant name Eaton Vance Corp.  
Entity central index key 0000350797  
Document type 10-K  
Document period end date Oct. 31, 2011  
Document Fiscal Year Focus 2011  
Document Fiscal Period Focus FY  
Amendment flag false  
Entity current reporting status Yes  
Entity voluntary filers No  
Current fiscal year end date --10-31  
Entity filer category Large Accelerated Filer  
Entity well known seasoned issuer Yes  
Entity common stock shares outstanding 115,623,067  
Entity public float   $ 3,885,082,674