Financial Instruments (Schedule Of Amounts Included In Earnings And Other Comprehensive Income) (Details) lb in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2018 USD ($) lb	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Financial Instruments [Line Items]
Notional value of foreign currency hedge positions	$ 1,900
Derivative, amount of commodities hedged	140
Gain (Loss) to earnings	0	$ (44)	$ (103)
Gain (Loss) to other comprehensive income	2	55	(47)
Foreign currency [Member] | Other deductions, net [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ (15)	(39)	(27)
Copper and aluminum [Member]
Financial Instruments [Line Items]
Weight of copper and aluminum for commodity hedges, in pounds | lb	52
Cash Flow Hedging [Member] | Commodity [Member] | Cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ 13	10	(35)
Cash Flow Hedging [Member] | Foreign currency [Member] | Sales, cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	2	(15)	(41)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Commodity [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	(7)	25	(9)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Foreign currency [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	$ 9	$ 30	$ (38)