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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	$ 27	$ (16)	$ 56	$ 11
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	(2)	(3)	2	(9)
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	19	(18)	68	(42)
Foreign Currency Exchange Derivatives | Discontinued Operations
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	0	(2)	0	52
Equity swap | Selling, General And Administrative
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	10	7	(14)	10
Cash Flow Hedging
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	5	(7)	4	5
Amount of Gain (Loss) Reclassified from AOCI into Income	(2)	1	0	(9)
Cash Flow Hedging | Foreign Currency Exchange Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	0	(2)	2	7
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	(4)	2	(1)	4
Cash Flow Hedging | Commodity Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	5	(5)	2	(2)
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	0	1	(3)
Cash Flow Hedging | Commodity Derivatives | Discontinued Operations
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	0	(1)	0	(10)
Net Investment Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	$ 46	$ 36	$ (58)	$ 48