Consolidated Statements of Equity (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Total	Total Costco Stockholders' Equity [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss)	Retained Earnings [Member]	Noncontrolling Interests
Equity at beginning of period at Aug. 28, 2011	$ 12,573	$ 12,002	$ 2	$ 4,516	$ 373	$ 7,111	$ 571
Common stock at beginning of period (shares) at Aug. 28, 2011			434,266
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,767	1,709				1,709	58
Foreign-currency translation adjustment and other, net	(96)	(62)			(62)		(34)
Stock-based compensation	241	241		241
Stock options exercised, including tax effects (shares)			2,756
Stock options exercised, including tax effects	142	142		142
Release of vested RSUs, including tax effects (shares)			2,554
Release of vested RSUs, including tax effects	(76)	(76)	0	(76)
Conversion of convertible notes (shares)			46
Conversion of convertible notes	2	2	0	2
Repurchases of common stock (shares)	(7,272)		(7,272)
Repurchases of common stock	(617)	(617)	0	(77)		(540)
Cash dividends declared	(446)	(446)				(446)
Distributions to noncontrolling interest	(183)						(183)
Purchase of noncontrolling interest in Costco Mexico	(789)	(534)		(379)	(155)		(255)
Equity at end of period at Sep. 02, 2012	12,518	12,361	2	4,369	156	7,834	157
Common stock at end of period (shares) at Sep. 02, 2012			432,350
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,061	2,039				2,039	22
Foreign-currency translation adjustment and other, net	(278)	(278)			(278)		0
Stock-based compensation	285	285		285
Stock options exercised, including tax effects (shares)			1,435
Stock options exercised, including tax effects	75	75	0	75
Release of vested RSUs, including tax effects (shares)			2,609
Release of vested RSUs, including tax effects	(85)	(85)	0	(85)
Conversion of convertible notes (shares)			802
Conversion of convertible notes	30	30	0	30
Repurchases of common stock (shares)	(357)		(357)
Repurchases of common stock	(34)	(34)	0	(4)		(30)
Cash dividends declared	(3,560)	(3,560)				(3,560)
Equity at end of period at Sep. 01, 2013	11,012	10,833	2	4,670	(122)	6,283	179
Common stock at end of period (shares) at Sep. 01, 2013	436,839		436,839
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,088	2,058				2,058	30
Foreign-currency translation adjustment and other, net	49	46			46		3
Stock-based compensation	327	327		327
Stock options exercised, including tax effects (shares)	971		971
Stock options exercised, including tax effects	58	58	0	58
Release of vested RSUs, including tax effects (shares)			2,770
Release of vested RSUs, including tax effects	(102)	(102)	0	(102)
Conversion of convertible notes (shares)			18
Conversion of convertible notes	1	1	0	1
Repurchases of common stock (shares)	(2,915)		(2,915)
Repurchases of common stock	(334)	(334)	0	(35)		(299)
Cash dividends declared	(584)	(584)				(584)
Equity at end of period at Aug. 31, 2014	$ 12,515	$ 12,303	$ 2	$ 4,919	$ (76)	$ 7,458	$ 212
Common stock at end of period (shares) at Aug. 31, 2014	437,683		437,683