Other Deductions, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Amortization of intangibles (intellectual property and customer relationships)	$ 211	$ 136	$ 84
Restructuring costs	65	78	96
Other	100	72	114
Total	376	286	294
Change in gain (loss) from foreign currency transactions		78
Increase (Decrease) in acquisition and divestiture related costs	$ 18	$ 24
Gain from dumping duties received			$ 21