XML 34 R25.htm IDEA: XBRL DOCUMENT
v3.21.4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions | 3 Months Ended
--- | ---
Nov. 21, 2021 USD ($) warehouse states
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 823
Impairment of Intangible Assets (Excluding Goodwill) | $ | $ 118
UNITED STATES |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 571
Number of states in country | states | 46
CANADA |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 105
MEXICO |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 39
UNITED KINGDOM |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 29
JAPAN |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 30
KOREA |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 16
TAIWAN |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 14
AUSTRALIA |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 13
SPAIN |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 3
ICELAND |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 1
FRANCE |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 1
CHINA |
Summary Of Significant Accounting Policies [Line Items] |
Number of warehouses operated | 1

X
- Definition Summary Of Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | cost_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | cost_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275 + Details
Name: | us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The number of states the entity operates in as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of stores. + References No definition available. + Details
Name: | us-gaap_NumberOfStores
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_MX
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_GB
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_JP
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_KR
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_TW
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_AU
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_ES
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_IS
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_FR
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CN
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |