Derivatives (Schedule of Derivative Instruments in Statement of Financial Position, Fair Value) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Sep. 30, 2012
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	$ 1		$ 3
Total Liability Derivatives	29		29
Designated as Hedging Instrument [Member] | Accounts Payable And Accrued Liabilities [Member] | Interest Rate Risk Management [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives			2	[1]
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	29		29
Not Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets And Other Assets [Member] | Other [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	1	[2]	1	[2]
Total Liability Derivatives			1	[2]
Not Designated as Hedging Instrument [Member] | Accounts Payable And Accrued Liabilities And Other Liabilities [Member] | Foreign Currency Risk Management [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	$ 29	[1]	$ 28	[1]

[1] (1) Contracts of less than a million and $2 million presented on a gross basis in this table at June 30, 2013 and September 30, 2012, respectively, have the legal right to offset against other types of contracts with a common counterparty and, therefore, are presented on a net basis in "Accounts payable and accrued liabilities" in the Consolidated Balance Sheet.

[2] (2) Contracts in an asset and liability position presented on a gross basis in this table have the legal right of offset and, therefore, are presented on a net basis in "Prepaid expenses and other current assets" in the Consolidated Balance Sheet.