Financial Instruments (Schedule Of Amounts Included In Earnings And Other Comprehensive Income) (Details) lb in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2017 USD ($) lb	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Financial Instruments [Line Items]
Notional value of foreign currency hedge positions	$ 1,800
Derivative, amount of commodities hedged	115
Gain (Loss) to earnings	(44)	$ (103)	$ (22)
Gain (Loss) to other comprehensive income	55	(47)	(104)
Foreign currency [Member] | Other deductions, net [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ (39)	(27)	14
Copper and aluminum [Member]
Financial Instruments [Line Items]
Weight of copper and aluminum for commodity hedges, in pounds | lb	49
Cash Flow Hedging [Member] | Commodity [Member] | Cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	$ 10	(35)	(24)
Cash Flow Hedging [Member] | Foreign currency [Member] | Sales, cost of sales [Member]
Financial Instruments [Line Items]
Gain (Loss) to earnings	(15)	(41)	(12)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Commodity [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	25	(9)	(43)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member] | Foreign currency [Member]
Financial Instruments [Line Items]
Gain (Loss) to other comprehensive income	$ 30	$ (38)	$ (61)