Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Millions	Total	Total Costco Stockholders' Equity	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests
Common stock at beginning of period (shares) at Sep. 02, 2012			432,350
Equity at beginning of period at Sep. 02, 2012	$ 12,518	$ 12,361	$ 2	$ 4,369	$ 156	$ 7,834	$ 157
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)
Common stock at end of period (shares) at Sep. 01, 2013			436,839
Equity at end of period at Sep. 01, 2013	11,012	10,833	$ 2	4,670	(122)	6,283	179
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
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)
Common stock at end of period (shares) at Aug. 31, 2014	437,683		437,683
Equity at end of period at Aug. 31, 2014	$ 12,515	12,303	$ 2	4,919	(76)	7,458	212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,409	2,377				2,377	32
Foreign-currency translation adjustment and other, net	(1,063)	(1,045)			(1,045)		(18)
Stock-based compensation	394	394		394
Stock options exercised, including tax effects (shares)			989
Stock options exercised, including tax effects	69	69	$ 0	69
Release of vested RSUs, including tax effects (shares)			2,736
Release of vested RSUs, including tax effects	$ (122)	(122)	$ 0	(122)
Repurchases of common stock (shares)	(3,456)		(3,456)
Repurchases of common stock	$ (494)	(494)	$ 0	(42)		(452)
Cash dividends declared	$ (2,865)	(2,865)				(2,865)
Common stock at end of period (shares) at Aug. 30, 2015	437,952		437,952
Equity at end of period at Aug. 30, 2015	$ 10,843	$ 10,617	$ 2	$ 5,218	$ (1,121)	$ 6,518	$ 226