Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Aug. 31, 2014	Sep. 01, 2013	Sep. 02, 2012
CASH FLOWS FROM OPERATING ACTIVITIES
Net income including noncontrolling interests	$ 2,088	$ 2,061	$ 1,767
Adjustments to reconcile net income including noncontrolling interests to net cash provided by operating activities:
Depreciation and amortization	1,029	946	908
Stock-based compensation	327	285	241
Excess tax benefits on stock-based awards	(84)	(61)	(64)
Other non-cash operating activities, net	22	(7)	28
Deferred income taxes	(63)	7	(3)
Changes in operating assets and liabilities:
Increase in merchandise inventories	(563)	(898)	(490)
Increase in accounts payable	529	718	338
Other operating assets and liabilities, net	699	386	332
Net cash provided by operating activities	3,984	3,437	3,057
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(2,503)	(2,572)	(2,048)
Maturities and sales of short-term investments	2,406	2,385	2,303
Additions to property and equipment	(1,993)	(2,083)	(1,480)
Other investing activities, net	(3)	19	(11)
Net cash used in investing activities	(2,093)	(2,251)	(1,236)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in bank checks outstanding	96	(70)	457
Repayments of short-term borrowings	(103)	(287)	(114)
Proceeds from short-term borrowings	68	326	114
Proceeds from issuance of long-term debt	117	3,717	130
Repayments of long-term debt	0	0	(900)
Distribution to noncontrolling interests	0	(22)	(161)
Proceeds from exercise of stock options	38	52	109
Minimum tax withholdings on stock-based awards	(164)	(121)	(107)
Excess tax benefits on stock-based awards	84	61	64
Repurchases of common stock	(334)	(36)	(632)
Cash dividend payments	(584)	(3,560)	(446)
Purchase of noncontrolling interest in Costco Mexico	0	0	(789)
Other financing activities, net	(4)	(16)	(6)
Net cash (used in) provided by financing activities	(786)	44	(2,281)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(11)	(114)	(21)
Net increase (decrease) in cash and cash equivalents	1,094	1,116	(481)
CASH AND CASH EQUIVALENTS BEGINNING OF YEAR	4,644	3,528	4,009
CASH AND CASH EQUIVALENTS END OF YEAR	5,738	4,644	3,528
Cash paid during the year for:
Interest (reduced by $11, $12 and $10, interest capitalized in 2014, 2013 and 2012, respectively)	109	86	112
Income taxes, net	$ 869	$ 1,001	$ 956