CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	9 Months Ended
	May 06, 2012	May 08, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income including noncontrolling interests	$ 1,145	$ 1,042
Adjustments to reconcile net income including noncontrolling interests to net cash provided by operating activities:
Depreciation and amortization	616	582
Stock-based compensation	179	152
Excess tax benefits on stock-based awards	(50)	(43)
Other non-cash operating activities, net	31	16
Deferred income taxes	(7)	(22)
Changes in operating assets and liabilities:
Increase in merchandise inventories	(434)	(357)
Increase in accounts payable	394	518
Other operating assets and liabilities, net	453	369
Net cash provided by operating activities	2,327	2,257
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(1,324)	(2,528)
Maturities of short-term investments	1,414	1,474
Sales of investments	303	465
Additions to property and equipment	(900)	(818)
Proceeds from the sale of property and equipment	10	9
Increase resulting from initial consolidation of Costco Mexico	0	165
Other investing activities, net	(20)	(5)
Net cash used in investing activities	(517)	(1,238)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in bank checks outstanding	412	35
Repayments of short-term borrowings	(114)	(33)
Proceeds from short-term borrowings	114	8
Proceeds from issuance of long-term debt	127	0
Repayments of long-term debt	(900)	0
Proceeds from exercise of stock options	71	273
Minimum tax withholdings on stock-based awards	(107)	(61)
Excess tax benefits on stock-based awards	50	43
Repurchases of common stock	(452)	(347)
Cash dividend payments	(209)	(179)
Other financing activities, net	(3)	(1)
Net cash used in financing activities	(1,011)	(262)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(17)	111
Net increase in cash and cash equivalents	782	868
CASH AND CASH EQUIVALENTS BEGINNING OF YEAR	4,009	3,214
CASH AND CASH EQUIVALENTS END OF PERIOD	4,791	4,082
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Interest (reduced by $6 interest capitalized in both 2012 and 2011)	111	110
Income taxes	495	459
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Decrease in accrued property and equipment	51	53
Cash dividend declared, but not yet paid	0	105
Unsettled repurchases of common stock	$ 13	$ 0