Derivative Financial Instruments - Summary of Amounts Recorded in Consolidated Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Sep. 30, 2013
Other Current Assets
Derivatives Fair Value [Line Items]
Other current assets			$ 1	[1]
Other Current Liabilities
Derivatives Fair Value [Line Items]
Other current liabilities	$ (2)	[2]	$ (23)	[1]

[1] Includes $5 million and $27 million of foreign exchange derivative contracts in asset and liability positions, respectively.

[2] Includes $1 million and $3 million of foreign exchange derivative contracts in asset and liability positions, respectively