Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2012
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 Joint Ventures	$ 30	$ 26	$ 41
Net advances to joint ventures (Less Than $1 Million For the Year Ended August 31, 2012)	3	2	1
Due to Affiliate		3
Accounts Receivable, Related Parties (MMGL - Immediate Family Member of Management or Principal Owner, Less Than $1 Million as of August 31, 2013)	1	1
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
Other Affiliates [Member]
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)			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	2	1	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)	$ 1	$ 1
Related Party Transaction Percentage Of Shared Legal And Consulting Costs	50.00%