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Equity (Tables) | 3 Months Ended
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Nov. 24, 2019
Equity [Abstract] |
Stock Repurchased During Period | Stock repurchase activity during the first quarter of 2020 and 2019 is summarized below:
| Shares Repurchased (000s) |  | Average Price per Share |  | Total Cost
First quarter of 2020 | 100 |  |  | $ | 295.97 |  |  | $ | 30 |
First quarter of 2019 | 150 |  |  | $ | 229.35 |  |  | $ | 34 |

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- Definition Schedule of Common Stock Repurchased And Average Price Paid Per Share [Table Text Block] + References No definition available. + Details
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Namespace Prefix: | cost_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | na
Period Type: | duration