v2.4.0.8
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended 1 Months Ended 12 Months Ended
Sep. 01, 2013
warehouse
Sep. 02, 2012
Aug. 28, 2011
Sep. 01, 2013
Forward Foreign Exchange Contracts
Sep. 02, 2012
Forward Foreign Exchange Contracts
Jul. 31, 2012
Costco Mexico
Sep. 01, 2013
UNITED STATES
warehouse
regions
Sep. 01, 2013
CANADA
warehouse
Sep. 01, 2013
MEXICO
warehouse
Sep. 01, 2013
UNITED KINGDOM
warehouse
Sep. 01, 2013
JAPAN
warehouse
Sep. 01, 2013
TAIWAN, PROVINCE OF CHINA
warehouse
Sep. 01, 2013
KOREA, REPUBLIC OF
warehouse
Sep. 01, 2013
AUSTRALIA
warehouse
Sep. 01, 2013
Building and Building Improvements [Member]
Minimum [Member]
Sep. 01, 2013
Building and Building Improvements [Member]
Maximum [Member]
Sep. 01, 2013
Furniture and Fixtures [Member]
Minimum [Member]
Sep. 01, 2013
Furniture and Fixtures [Member]
Maximum [Member]
Sep. 01, 2013
Software [Member]
Minimum [Member]
Sep. 01, 2013
Software [Member]
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]                                        
Asset Retirement Obligations, Noncurrent $ 50 $ 44                                    
Maximum Reward Rebate Amount Per Customer Yearly 2.00%                                      
Property, Plant and Equipment, Useful Life                             5 years 50 years 3 years 20 years 3 years 7 years
Payments To Acquire Minority Interest 0 789 0                                  
Reduction In Sales 970 900 790                                  
Accrued Insurance 727 688                                    
Outstanding Checks Unpresented For Payment 493 565                                    
Credit and Debit Card Receivables, at Carrying Value 1,254 1,161                                    
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets     357                                  
Number of warehouses operated 634           451 85 33 25 18 10 9 3            
Number of regions in country             41                          
Purchase of equity interest           50.00%                            
Cumulative Impact To Consolidated Assets Liabilities And Equity From Adoption Of New Accounting Principle     3.00%                                  
Inventory, LIFO Reserve, Period Charge 27 21 87                                  
Inventory LIFO reserve cumulative impact 81 108                                    
Notional amount of forward foreign - exchange derivative       $ 458 $ 284