The cumulative impact to total consolidated assets, liabilities and equity as a result of the adoption of FASB Statement No. 167, Amendments to FASB interpretation No. 46(R), as codified in FASB Accounting Standards Codification Topic 810, Consolidation, effective August 30, 2010 (beginning of fiscal year 2011)

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- Definition

The cumulative impact to noncontrolling interests as a result of the adoption of FASB Statement No. 167, Amendments to FASB Interpretation No. 46(R), as codified in FASB Accounting Standards Codification Topic 810, Consolidation, effective August 30, 2010 (beginning of fiscal year 2011)

+ Details

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- Definition

The change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods, which change has been reflected in the statement of income during the period.

+ Details

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- Definition

Number of states or provinces within a country where Costco has warehouses

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- Definition

Number of warehouses operated by country

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- Definition

The percentage of warehouses, where the entity enters into fixed price derivative contracts to mitigate the risk of price fluctuations for commodities such as electric and natural gas) consumed by the warehouse as part of normal operations.

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- Definition

Aggregate notional amount of foreign currency exchange rate derivatives. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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Summary of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended
	May 08, 2011	May 08, 2011	Aug. 29, 2010
Initial consolidation of noncontrolling interest in the Costco Mexico joint venture		$ 357	$ 357
Charge to merchandise costs	49	55
Percent of warehouses under fixed-price contracts with counterparties		38.00%
Cumulative impact to consolidated assets, liabilities and equity from adoption of new accounting principle		3.00%
Consolidated [Member]
Number of warehouses operated		580
U. S. and Puerto Rico [Member]
Number of regions in country		40
Number of warehouses operated		425
Canada [Member]
Number of regions in country		9
Number of warehouses operated		80
United Kingdom [Member]
Number of warehouses operated		22
Japan [Member]
Number of warehouses operated		7
Korea [Member]
Number of warehouses operated		7
Taiwan [Member]
Number of warehouses operated		6
Australia [Member]
Number of warehouses operated		1
Mexico [Member]
Number of warehouses operated		32
Forward Foreign Exchange Contracts [Member]
Notional amount of derivatives	$ 221	$ 221	$ 225