|
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 | ||||||||||||||||||