Financial Instruments (Schedule Of Derivative Instruments) (Details) lb in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018 USD ($) lb	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) lb	Jun. 30, 2017 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified to earnings	$ 29	$ (18)	$ 28	$ (33)
Gain (loss) to other comprehensive income	(18)	12	(18)	49
Commodity Contract [Member] | Cash Flow Hedging [Member] | Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to other comprehensive income	(3)	2	1	17
Commodity Contract [Member] | Cash Flow Hedging [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified to earnings	2	4	13	6
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of foreign currency hedge positions	2,300		2,300
Foreign Exchange Contract [Member] | Other deductions, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified to earnings	28	(22)	16	(22)
Foreign Exchange Contract [Member] | Cash Flow Hedging [Member] | Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to other comprehensive income	(15)	10	(19)	32
Foreign Exchange Contract [Member] | Cash Flow Hedging [Member] | Sales, Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified to earnings	(1)	$ 0	(1)	$ (17)
All Commodity Hedges [Member] [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of commodities hedged	$ 142		$ 142
Copper and Aluminum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weight in pounds of copper and aluminum commodity hedges | lb	53		53