Equity - Additional Information - Stock Repurchase Programs (Details) - USD ($) $ in Millions	Feb. 12, 2023	Jan. 19, 2023
Equity [Abstract]
Stock repurchase program, remaining authorized repurchase amount	$ 3,955
Stock Repurchase Program, Authorized Amount		$ 4,000
PreviouslyAuthorizedButUnusedShareRepurchaseAmountsRevoked		$ 2,568

Amount revoked from previous authorized but unused share repurchase amounts

No definition available.

Name:	cost_PreviouslyAuthorizedButUnusedShareRepurchaseAmountsRevoked
Namespace Prefix:	cost_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant