Restructuring (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011
Restructuring and Related Cost [Line Items]
Number of stores converted to date	5,843		5,843
Number of new stores opened to date	559		559
Total restructuring program costs related to the Customer Centric Retailing initiative	$ 0	$ 7	$ 33	$ 17
Amount of total restructuring program costs included in selling, general and administrative expenses	0	4	15	10
Amount of total restructuring program costs that were capitalized	0	3	18	7
Restructuring And Restructuring Related Costs [Member] | Selling General And Administrative Expense [Member]
Restructuring and Related Cost [Line Items]
Pre-tax charges associated with Company's restructuring initiatives		$ 6		$ 13