XML 49 R40.htm IDEA: XBRL DOCUMENT v3.7.0.1

Income Taxes Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		8 Months Ended
	May 07, 2017	May 08, 2016	May 07, 2017	May 08, 2016
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, Percent	26.80%	34.20%	32.00%	34.70%
Discrete Income Tax Benefit	$ 82		$ 88
Special Dividend [Member]
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	$ 82
Four Zero One K Plan [Member]
Income Taxes [Line Items]
Shares, Outstanding	30,000,000		30,000,000

X

- Definition

Discrete Income Tax Benefit

+ References

No definition available.

+ Details

Name:	cost_DiscreteIncomeTaxBenefit
Namespace Prefix:	cost_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Income Taxes [Line Items]

+ References

No definition available.

+ Details

Name:	cost_IncomeTaxesLineItems
Namespace Prefix:	cost_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319

+ Details

Name:	us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for dividend.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319

+ Details

Name:	us-gaap_IncomeTaxReconciliationDeductionsDividends
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Number of shares issued which are neither cancelled nor held in the treasury.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	cost_DividendsPaidAxis=cost_SpecialDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=cost_FourZeroOneKPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: