Changes in Equity Attributes to Costco and the Noncontrolling Interests of Consolidated Subsidiaries (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 22, 2015	Nov. 23, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period	$ 10,843	$ 12,515
Comprehensive income:
Net income	487	505
Foreign-currency translation adjustment and other, net	15	(322)
COMPREHENSIVE INCOME ATTRIBUTABLE TO COSTCO	496	184
Comprehensive income	502	183
Comprehensive income (loss), net of tax, attributable to noncontrolling interest	6	(1)
Stock-based compensation	186	150
Stock options exercised, including tax effects		17
Release of vested restricted stock units (RSUs), including tax effects	(145)	(121)
Repurchases of common stock	(130)	(18)
Cash dividends declared	(176)	(156)
Equity at end of period	11,080	12,570
Attributable to Costco
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period	10,617	12,303
Comprehensive income:
Net income	480	496
Foreign-currency translation adjustment and other, net	16	(312)
Stock-based compensation	186	150
Stock options exercised, including tax effects		17
Release of vested restricted stock units (RSUs), including tax effects	(145)	(121)
Repurchases of common stock	(130)	(18)
Cash dividends declared	(176)	(156)
Equity at end of period	10,848	12,359
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period	226	212
Comprehensive income:
Net income	7	9
Foreign-currency translation adjustment and other, net	(1)	(10)
Equity at end of period	$ 232	$ 211