Derivative Instruments and Hedging Activities - Effects on Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Sep. 30, 2014
Derivatives, Fair Value [Line Items]
Asset derivatives	$ 17	$ 23
Liability derivatives	19	14
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	9	3
Derivatives Designated as Hedging Instruments [Member] | Commodity Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	6
Derivatives Not Designated as Hedging Instruments [Member] | Forward Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	8	20
Liability derivatives	$ 13	$ 14