Derivative Instruments and Hedging Activities Location and Amount of Gains and Losses Gross of Tax on Derivative Instruments and Related Hedge Items (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ 82	$ (3)	$ 27
Foreign currency exchange derivatives | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(1)	(8)	4
Foreign currency exchange derivatives | Net financing charges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	87	(60)	42
Foreign currency exchange derivatives | Income tax provision
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	0	(1)	(4)
Foreign currency exchange derivatives | Discontinued Operations
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	0	52	(7)
Equity swap | Selling, general and administrative
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(4)	14	(8)
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	7	(2)	(12)
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(3)	(10)	16
Cash Flow Hedging | Foreign currency exchange derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	1	2	2
Cash Flow Hedging | Foreign currency exchange derivatives | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(5)	4	2
Cash Flow Hedging | Foreign currency exchange derivatives | Discontinued Operations
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	0	0	2
Cash Flow Hedging | Commodity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	6	(4)	(14)
Cash Flow Hedging | Commodity derivatives | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	2	(4)	5
Cash Flow Hedging | Commodity derivatives | Discontinued Operations
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	$ 0	$ (10)	$ 7