Derivative Instruments and Hedging Activities - Effects on Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014
Derivatives, Fair Value [Line Items]
Asset derivatives	$ 32	$ 23
Liability derivatives	30	14
Derivatives Designated as Hedging Instruments | Interest rate swaps
Derivatives, Fair Value [Line Items]
Asset derivatives	19	3
Derivatives Designated as Hedging Instruments | Commodity forward contracts
Derivatives, Fair Value [Line Items]
Liability derivatives	10	0
Derivatives Not Designated as Hedging Instruments | Forward exchange contracts
Derivatives, Fair Value [Line Items]
Asset derivatives	13	20
Liability derivatives	$ 21	$ 14