Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended						4 Months Ended		12 Months Ended
	May 10, 2020	Feb. 16, 2020	Nov. 24, 2019	May 12, 2019	Feb. 17, 2019	Nov. 25, 2018	Aug. 30, 2020	Sep. 01, 2019	Aug. 30, 2020	Sep. 01, 2019	Sep. 02, 2018
REVENUE
Total revenue	$ 37,266	$ 39,072	$ 37,040	$ 34,740	$ 35,396	$ 35,069	$ 53,383	$ 47,498	$ 166,761	$ 152,703	$ 141,576
OPERATING EXPENSES
Merchandise costs	32,249	34,056	32,233	30,233	30,720	30,623	46,401	41,310	144,939	132,886	123,152
Selling, general and administrative	3,830	3,743	3,732	3,371	3,464	3,475	5,027	4,684	16,332	14,994	13,876
Preopening expenses	8	7	14	14	9	22	26	41	55	86	68
Operating Income	1,179	1,266	1,061	1,122	1,203	949	1,929	1,463	5,435	4,737	4,480
OTHER INCOME (EXPENSE)
Interest expense	(37)	(34)	(38)	(35)	(34)	(36)	(51)	(45)	(160)	(150)	(159)
Interest income and other, net	21	45	35	36	46	22	(9)	74	92	178	121
INCOME BEFORE INCOME TAXES	1,163	1,277	1,058	1,123	1,215	935	1,869	1,492	5,367	4,765	4,442
Provision for income taxes	311	330	202	207	314	158	465	382	1,308	1,061	1,263
Net income including noncontrolling interests	852	947	856	916	901	777	1,404	1,110	4,059	3,704	3,179
Net income attributable to noncontrolling interests	(14)	(16)	(12)	(10)	(12)	(10)	(15)	(13)	(57)	(45)	(45)
NET INCOME ATTRIBUTABLE TO COSTCO	$ 838	$ 931	$ 844	$ 906	$ 889	$ 767	$ 1,389	$ 1,097	$ 4,002	$ 3,659	$ 3,134
NET INCOME PER COMMON SHARE ATTRIBUTABLE TO COSTCO:
Basic (in dollars per share)	$ 1.90	$ 2.10	$ 1.91	$ 2.06	$ 2.02	$ 1.75	$ 3.14	$ 2.49	$ 9.05	$ 8.32	$ 7.15
Diluted (in dollars per share)	$ 1.89	$ 2.10	$ 1.90	$ 2.05	$ 2.01	$ 1.73	$ 3.13	$ 2.47	$ 9.02	$ 8.26	$ 7.09
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic (shares)	442,322	442,021	441,818	439,859	440,284	439,157	442,843	439,727	442,297	439,755	438,515
Diluted (shares)	443,855	443,727	443,680	442,642	442,337	442,749	444,231	443,400	443,901	442,923	441,834
Net sales
REVENUE
Total revenue	$ 36,451	$ 38,256	$ 36,236	$ 33,964	$ 34,628	$ 34,311	$ 52,277	$ 46,448	$ 163,220	$ 149,351	$ 138,434
Membership fees
REVENUE
Total revenue	$ 815	$ 816	$ 804	$ 776	$ 768	$ 758	$ 1,106	$ 1,050	$ 3,541	$ 3,352	$ 3,142