Financial Instruments (Schedule Of Amounts Included In Earnings And Other Comprehensive Income) (Details) lb in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($) lb	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Financial Instruments [Line Items]
Notional value of foreign currency hedge positions	$ 2,300
Derivative, amount of commodities hedged	117
Gain (Loss) to earnings	68	$ 0	$ (44)
Gain (Loss) to other comprehensive income	(4)	2	55
Foreign currency [Member] | Other deductions, net [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ 66	(15)	(39)
Copper and aluminum [Member]
Financial Instruments [Line Items]
Weight of copper and aluminum for commodity hedges, in pounds | lb	48
Cash Flow Hedging [Member] | Commodity [Member] | Cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ (11)	13	10
Cash Flow Hedging [Member] | Foreign currency [Member] | Sales, cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	13	2	(15)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Commodity [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	(10)	(7)	25
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Foreign currency [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	$ 6	$ 9	$ 30