Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended							4 Months Ended		12 Months Ended
	May 07, 2017		Feb. 12, 2017	Nov. 20, 2016	May 08, 2016	Feb. 14, 2016	Nov. 22, 2015	Sep. 03, 2017	Aug. 28, 2016	Sep. 03, 2017	Aug. 28, 2016	Aug. 30, 2015
REVENUE
Net sales	$ 28,216		$ 29,130	$ 27,469	$ 26,151	$ 27,567	$ 26,627	$ 41,357	$ 35,728	$ 126,172	$ 116,073	$ 113,666
Membership fees	644		636	630	618	603	593	943	832	2,853	2,646	2,533
Total revenue	28,860		29,766	28,099	26,769	28,170	27,220	42,300	36,560	129,025	118,719	116,199
OPERATING EXPENSES
Merchandise costs	24,970		25,927	24,288	23,162	24,469	23,621	36,697	31,649	111,882	102,901	101,065
Selling, general and administrative	2,907		2,980	2,940	2,731	2,835	2,806	4,123	3,696	12,950	12,068	11,445
Preopening expenses	15		15	22	18	10	26	30	24	82	78	65
Operating income	968		844	849	858	856	767	1,450	1,191	4,111	3,672	3,624
OTHER INCOME (EXPENSE)
Interest expense	(21)		(31)	(29)	(30)	(31)	(33)	(53)	(39)	(134)	(133)	(124)
Interest income and other, net	18		(4)	26	7	16	28	22	29	62	80	104
INCOME BEFORE INCOME TAXES	965		809	846	835	841	762	1,419	1,181	4,039	3,619	3,604
Provision for income taxes	259	[1]	288	291	286	286	275	487	396	1,325	1,243	1,195
Net income including noncontrolling interests	706		521	555	549	555	487	932	785	2,714	2,376	2,409
Net income attributable to noncontrolling interests	(6)		(6)	(10)	(4)	(9)	(7)	(13)	(6)	(35)	(26)	(32)
NET INCOME ATTRIBUTABLE TO COSTCO	$ 700		$ 515	$ 545	$ 545	$ 546	$ 480	$ 919	$ 779	$ 2,679	$ 2,350	$ 2,377
NET INCOME PER COMMON SHARE ATTRIBUTABLE TO COSTCO:
Basic (in dollars per share)	$ 1.59		$ 1.17	$ 1.24	$ 1.24	$ 1.24	$ 1.10	$ 2.10	$ 1.78	$ 6.11	$ 5.36	$ 5.41
Diluted (in dollars per share)	$ 1.59		$ 1.17	$ 1.24	$ 1.24	$ 1.24	$ 1.09	$ 2.08	$ 1.77	$ 6.08	$ 5.33	$ 5.37
Shares used in calculation (000's)
Basic (shares)	438,817		439,127	438,007	438,815	439,648	438,342	437,987	437,809	438,437	438,585	439,455
Diluted (shares)	441,056		440,657	440,525	441,066	441,559	441,386	441,036	440,868	440,937	441,263	442,716
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 7.50	[2]	$ 0.45	$ 0.45	$ 0.45	$ 0.40	$ 0.40	$ 0.50	$ 0.45	$ 8.90	$ 1.70	$ 6.51

[1] Includes an $82 tax benefit recorded in the third quarter in connection with the special cash dividend paid to employees through the Company's 401(k) Retirement Plan.

[2] Includes the special cash dividend of $7.00 per share paid in May 2017.