Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified				3 Months Ended										3 Months Ended
	Nov. 30, 2012 Corporate Joint Venture [Member]	Aug. 31, 2012 Corporate Joint Venture [Member]	Aug. 31, 2012 Other Affiliates [Member]	Nov. 30, 2012 Immediate Family Member of Management or Principal Owner [Member]	Nov. 30, 2012 Corporate Joint Venture [Member]	Nov. 30, 2011 Corporate Joint Venture [Member]	Nov. 30, 2012 Maximum [Member] Corporate Joint Venture [Member]	Nov. 30, 2011 Maximum [Member] Corporate Joint Venture [Member]	Nov. 30, 2012 Maximum [Member] Minority Shareholder Of Subsidiary [Member]	Aug. 31, 2012 Maximum [Member] Minority Shareholder Of Subsidiary [Member]	Nov. 30, 2012 Maximum [Member] Immediate Family Member of Management or Principal Owner [Member]	Aug. 31, 2012 Maximum [Member] Immediate Family Member of Management or Principal Owner [Member]	Nov. 30, 2012 Partnership Interest [Member] store	Nov. 30, 2012 Partnership Interest [Member] Auto Parts Business Segment President [Member]	Nov. 30, 2011 Partnership Interest [Member] Auto Parts Business Segment President [Member]	Nov. 30, 2012 Partnership Interest [Member] Maximum [Member] Auto Parts Business Segment President [Member]	Nov. 30, 2011 Partnership Interest [Member] Maximum [Member] Auto Parts Business Segment President [Member]	Nov. 30, 2011 Amix Salvage And Sales Ltd [Member] Minority Shareholder Of Subsidiary [Member]	Nov. 30, 2012 Amix Salvage And Sales Ltd [Member] Maximum [Member] Minority Shareholder Of Subsidiary [Member]
Related Party Transaction [Line Items]
Purchases from joint ventures					$ 6	$ 10
Advances to (payments from)							1	1
Due to Affiliate	3	2
Related Party Transaction, Expenses from Transactions with Related Party																		3	1
Accounts Payable, Related Parties									1	1
Related Party Noncontrolling Ownership Percentage By Noncontrolling Owners														25.00%
Related Party Noncontrolling Ownership Percentage By Parent														75.00%
Related Party Number Of Stores													5
Related Party Transaction Related Party Share Of Profit															1	1
Related Party Transaction Rent Expense																1	1
Related Party Transaction Lease Term														5 years
Related Party Transaction Percentage Of Shared Legal And Consulting Costs				50.00%
Accounts Receivable, Related Parties			$ 1								$ 1	$ 1