v2.3.0.15
Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)
3 Months Ended12 Months Ended
May 08, 2011
Feb. 13, 2011
Aug. 28, 2011
Aug. 28, 2011
Aug. 29, 2010
Aug. 30, 2009
Initial consolidation of noncontrolling interest in the Costco Mexico joint ventures   $ 357,000,000$ 357,000,000 
Credit and debit card receivables  982,000,000982,000,000862,000,000 
Charge (benefit) to merchandise costs49,000,0006,000,00032,000,00087,000,000 32,000,000
Percent of warehouses under fixed-price contracts with counterparties   36.00%  
Increase to total assets and liabilities due to consolidation   3.00%  
Impairment charges   1,000,0002,000,00011,000,000
Equity in earnings of Costco, Mexico    41,000,00032,000,000
Undistributed earnings of Mexico    307,000,000 
Impairment of goodwill   0  
Excess of outstanding checks over cash on deposit  108,000,000108,000,000617,000,000 
Estimated accruals for insurance liabilities  595,000,000595,000,000541,000,000 
Reserve for closing costs  5,000,0005,000,0005,000,000 
Gain (losses) on foreign currency transaction   8,000,00013,000,000 
Reward rate   2.00%  
Maximum reward rebate amount per customer, yearly   500  
Reduction in sales   790,000,000688,000,000610,000,000
Capital leases for warehouse locations  44  
Operating Lease [Member]
      
Year leases expire   2051  
Operating Lease [Member] | United Kingdom [Member]
      
Year leases expire   2151  
Capital Lease [Member]
      
Year leases expire   2040  
Consolidated [Member]
      
Number of warehouses operated   592  
U. S. And Puerto Rico [Member]
      
Number of regions in country   40  
Number of warehouses operated   429  
Canada [Member]
      
Number of regions in country   9  
Number of warehouses operated   82  
United Kingdom [Member]
      
Number of warehouses operated   22  
Japan [Member]
      
Number of warehouses operated   9  
Korea [Member]
      
Number of warehouses operated   7  
Taiwan [Member]
      
Number of warehouses operated   8  
Australia [Member]
      
Number of warehouses operated   3  
Mexico [Member]
      
Number of warehouses operated   32  
Forward Foreign Exchange Contracts [Member]
      
Notional amount of foreign exchange derivatives  $ 247,000,000$ 247,000,000$ 225,000,000