Changes in Equity Attributes to Costco and the Noncontrolling Interests of Consolidated Subsidiaries (Details) - USD ($) $ in Millions	3 Months Ended		8 Months Ended
	May. 08, 2016	May. 10, 2015	May. 08, 2016	May. 10, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period			$ 10,843	$ 12,515
Comprehensive income:
Net income	$ 549	$ 519	1,591	1,631
Foreign-currency translation adjustment and other, net	224	76	(5)	(656)
COMPREHENSIVE INCOME ATTRIBUTABLE TO COSTCO	763	587	1,566	960
Comprehensive income (loss), net of tax, attributable to noncontrolling interest	10	8	20	15
Comprehensive income	773	595	1,586	975
Stock-based compensation			362	301
Stock options exercised, including tax effects				68
Release of vested restricted stock units (RSUs), including tax effects			(145)	(121)
Repurchases of common stock	(136)	(124)	(346)	(234)
Cash dividends declared			(549)	(2,690)
Distribution to noncontrolling interest			(3)
Equity at end of period	11,748	10,814	11,748	10,814
Attributable to Costco
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period			10,617	12,303
Comprehensive income:
Net income			1,571	1,610
Foreign-currency translation adjustment and other, net			(5)	(650)
Stock-based compensation			362	301
Stock options exercised, including tax effects				68
Release of vested restricted stock units (RSUs), including tax effects			(145)	(121)
Repurchases of common stock			(346)	(234)
Cash dividends declared			(549)	(2,690)
Equity at end of period	11,505	10,587	11,505	10,587
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity at beginning of period			226	212
Comprehensive income:
Net income			20	21
Foreign-currency translation adjustment and other, net			0	(6)
Distribution to noncontrolling interest			(3)
Equity at end of period	$ 243	$ 227	$ 243	$ 227