Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 01, 2013	Sep. 02, 2012	Aug. 28, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income including noncontrolling interests	$ 2,061	$ 1,767	$ 1,542
Adjustments to reconcile net income including noncontrolling interests to net cash provided by operating activities:
Depreciation and amortization	946	908	855
Stock-based compensation	285	241	207
Excess tax benefits on stock-based awards	(61)	(64)	(45)
Other non-cash operating activities, net	(7)	28	23
Deferred income taxes	7	(3)	84
Changes in operating assets and liabilities, net of the initial consolidation of Costco Mexico at the beginning of fiscal 2011:
Increase in merchandise inventories	(898)	(490)	(642)
Increase in accounts payable	718	338	804
Other operating assets and liabilities, net	386	332	370
Net cash provided by operating activities	3,437	3,057	3,198
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(2,572)	(2,048)	(3,276)
Maturities of short-term investments	2,141	1,821	2,614
Sales of investments	244	482	602
Additions to property and equipment	(2,083)	(1,480)	(1,290)
Increase resulting from initial consolidation of Costco Mexico	0	0	165
Other investing activities, net	19	(11)	5
Net cash used in investing activities	(2,251)	(1,236)	(1,180)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in bank checks outstanding	(70)	457	(514)
Repayments of short-term borrowings	(287)	(114)	(105)
Proceeds from short-term borrowings	326	114	79
Proceeds from issuance of long-term debt	3,717	130	0
Repayments of long-term debt	0	(900)	0
(Distribution to) investment by noncontrolling interests	(22)	(161)	9
Proceeds from exercise of stock options	52	109	285
Minimum tax withholdings on stock-based awards	(121)	(107)	(61)
Excess tax benefits on stock-based awards	61	64	45
Repurchases of common stock	(36)	(632)	(624)
Cash dividend payments	(3,560)	(446)	(389)
Purchase of noncontrolling interest in Costco Mexico	0	(789)	0
Other financing activities, net	(16)	(6)	(2)
Net cash provided by (used in) financing activities	44	(2,281)	(1,277)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(114)	(21)	54
Net increase (decrease) in cash and cash equivalents	1,116	(481)	795
CASH AND CASH EQUIVALENTS BEGINNING OF YEAR	3,528	4,009	3,214
CASH AND CASH EQUIVALENTS END OF PERIOD	4,644	3,528	4,009
Cash paid during the first thirty-six weeks of year for:
Interest (reduced by $12, $10 and $9 interest capitalized in 2013, 2012 and 2011, respectively)	86	112	111
Income taxes	1,001	956	742
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Increase in accrued property and equipment	40	0	0
Property acquired under capital lease	11	18	0
Unsettled repurchases of common stock	0	2	17
Cash dividend declared, but not yet paid	0	22	0
Common stock issued upon conversion of 3.5% Zero Coupon Convertible Subordinated Notes	$ 30	$ 2	$ 2