Changes in Equity Attributes to Costco and the Noncontrolling Interests of Consolidated Subsidiaries (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Nov. 25, 2012	Nov. 20, 2011
Equity And Comprehensive Income [Line Items]
Beginning Balance	$ 12,518	$ 12,573
Comprehensive income:
Net income	421	328
Foreign-currency translation adjustment and other, net	22	(209)
Comprehensive income	443	119
Stock-based compensation	93	76
Stock options exercised, including tax effects	14	60
Release of vested restricted stock units (RSUs), including tax effects	(83)	(104)
Conversion of convertible notes	1	1
Repurchases of common stock	(34)	(173)
Cash dividends declared	(120)	(105)
Ending Balance	12,832	12,447
Attributable to Costco
Equity And Comprehensive Income [Line Items]
Beginning Balance	12,361	12,002
Comprehensive income:
Net income	416	320
Foreign-currency translation adjustment and other, net	17	(168)
Comprehensive income	433	152
Stock-based compensation	93	76
Stock options exercised, including tax effects	14	60
Release of vested restricted stock units (RSUs), including tax effects	(83)	(104)
Conversion of convertible notes	1	1
Repurchases of common stock	(34)	(173)
Cash dividends declared	(120)	(105)
Ending Balance	12,665	11,909
Noncontrolling Interest
Equity And Comprehensive Income [Line Items]
Beginning Balance	157	571
Comprehensive income:
Net income	5	8
Foreign-currency translation adjustment and other, net	5	(41)
Comprehensive income	10	(33)
Stock-based compensation	0	0
Stock options exercised, including tax effects	0	0
Release of vested restricted stock units (RSUs), including tax effects	0	0
Conversion of convertible notes	0	0
Repurchases of common stock	0	0
Cash dividends declared	0	0
Ending Balance	$ 167	$ 538