v2.4.0.8
Document and Entity Information (USD $)
12 Months Ended
Sep. 01, 2013
Oct. 09, 2013
Feb. 17, 2013
Document and Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Sep. 01, 2013    
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus FY    
Trading Symbol COST    
Entity Registrant Name COSTCO WHOLESALE CORP /NEW    
Entity Central Index Key 0000909832    
Current Fiscal Year End Date --09-01    
Entity Well-known Seasoned Issuer Yes    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   436,922,037  
Entity Public Float     $ 44,218,428,626