Derivative Instruments and Hedging Activities - Location and Amount of Gains and Losses Gross of Tax on Derivative Instruments and Related Hedge Items (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ 21	$ 0	$ 39	$ 19
Foreign Currency Exchange Derivatives | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(3)	0	(3)	23
Foreign Currency Exchange Derivatives | Net Financing Charges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	11	(1)	10	(30)
Foreign Currency Exchange Derivatives | Provision For Income Taxes
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(8)	(4)	(4)	0
Equity swap | Selling, General And Administrative
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	21	5	36	26
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	5	(6)	11	(25)
Amount of Gain (Loss) Recognized in AOCI on Derivative	4	2	4	2	12
Cash Flow Hedging | Foreign Currency Exchange Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative	0	(4)	0	(4)	(3)
Cash Flow Hedging | Foreign Currency Exchange Derivatives | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	0	(4)	1	(10)
Cash Flow Hedging | Commodity Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative	(3)	(2)	(3)	(2)	7
Cash Flow Hedging | Commodity Derivatives | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	4	(3)	9	(16)
Cash Flow Hedging | Forward Treasury Locks
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative	7	8	7	8	8
Cash Flow Hedging | Forward Treasury Locks | Net Financing Charges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	1	1	1	1
Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	0	0	0	0
Fair Value Hedging | Interest Rate Swaps | Net Financing Charges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(2)	2	(3)	(6)
Fair Value Hedging | Fixed Rate Debt Swapped to Floating | Net Financing Charges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ 2	$ (2)	$ 3	$ 6