Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Nov. 30, 2010	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Related Party Transaction [Line Items]
Business Acquisition, Effective Date of Acquisition		Mar. 31, 2011
Redeemable Noncontrolling Interest Purchase Date		Mar. 08, 2013
Corporate Joint Venture
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party		$ 26	$ 41	$ 48
Advances to joint ventures (Less Than $1 Million For the Year Ended August 31, 2012)		2	1
Payments from joint ventures				2
Due to Affiliate		3	2
Accounts Receivable, Related Parties (MMGL - Immediate Family Member of Management or Principal Owner, Less Than $1 Million as of August 31, 2013 and 2012)		1	1
Investments in and Advances to Affiliates, at Fair Value, Gross Additions	2
Minority Shareholder Of Subsidiary | Amix Salvage And Sales Ltd.
Related Party Transaction [Line Items]
Business Acquisition, Effective Date of Acquisition		Mar. 31, 2011
Redeemable Noncontrolling Interest Purchase Date		Mar. 08, 2013
Related Party Transaction, Expenses from Transactions with Related Party		5	9	3
Accounts Payable, Related Parties (Less Than $1 Million As Of August 31, 2012)			1
Other Affiliates
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties (MMGL - Immediate Family Member of Management or Principal Owner, Less Than $1 Million as of August 31, 2013 and 2012)			1
Auto Parts Business Segment President | Partnership Interest
Related Party Transaction [Line Items]
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	2	2
Lease Expiration Date		Mar. 31, 2016
Related Party Transaction Rent Expense		1	1	1
Immediate Family Member of Management or Principal Owner
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties (MMGL - Immediate Family Member of Management or Principal Owner, Less Than $1 Million as of August 31, 2013 and 2012)		1	1
Related Party Transaction Percentage Of Shared Legal And Consulting Costs		50.00%
Director
Related Party Transaction [Line Items]
Related Party Transaction, Revenues from Transactions with Related Party (Less Than $1 Million For The Year Ended August 31, 2011)				1
Related Parties Amount in Cost of Sales (Less Than $1 Million For The Year Ended August 31, 2011)				$ 1