Derivative Instruments and Hedging Activities - Location and Amount of Gains and Losses on Derivative Instruments and Related Hedge Items (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	$ (12)	$ 7	$ (6)	$ 14
Foreign Currency Exchange Derivatives | Cost of Sales
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(4)	2	(2)	3
Foreign Currency Exchange Derivatives | Discontinued Operations [Domain]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	0	0	0	5
Foreign Currency Exchange Derivatives | Net Financing Charges
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(3)	5	1	9
Foreign Currency Exchange Derivatives | Provision For Income Tax [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	0	0	2	(3)
Equity swap | Selling, General And Administrative
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(5)	0	(7)	0
Net Investment Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(100)	(19)	(136)	28
Cash Flow Hedging
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(6)	1	3	11
Amount of Gain (Loss) Reclassified from AOCI into Income	2	11	9	20
Cash Flow Hedging | Foreign Currency Exchange Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(5)	(2)	1	6
Cash Flow Hedging | Foreign Currency Exchange Derivatives | Cost of Sales
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	(2)	8	0	16
Cash Flow Hedging | Commodity Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(1)	3	2	5
Cash Flow Hedging | Commodity Derivatives | Cost of Sales
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	4	3	9	4
Fair Value Hedging
Fair Value Hedge [Abstract]
Gain (Loss) Recognized in Income, Fair Value Hedge	0	0	0	1
Fair Value Hedging | Interest Rate Swaps | Net Financing Charges
Fair Value Hedge [Abstract]
Gain (Loss) Recognized in Income, Fair Value Hedge	0	0	0	(1)
Fair Value Hedging | Fixed Rate Debt Swapped to Floating | Net Financing Charges
Fair Value Hedge [Abstract]
Gain (Loss) Recognized in Income, Fair Value Hedge	$ 0	$ 0	$ 0	$ 2