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		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	$ (34)	$ 50	$ (40)	$ 64
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)	(4)	(6)	(1)
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	(27)	51	(26)	60
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	1	2	(2)
Equity swap | Selling, General And Administrative
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(3)	2	(10)	2
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	165	(105)	29	(77)
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	(2)	9	9
Amount of Gain (Loss) Reclassified from AOCI into Income	4	11	13	31
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	6	(3)	7	3
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	2	24
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	0	1	2	6
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	2	3	11	7
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