Reportable Segment Information - Sales and Property, Plant and Equipment by Geographical Area (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Sales	$ 2,981	$ 2,353	$ 2,390
Property, plant and equipment, net	817	613
United States
Segment Reporting Information [Line Items]
Sales	2,209	1,775	1,766
Property, plant and equipment, net	700	512
Non-US [Member]
Segment Reporting Information [Line Items]
Sales	772	578	$ 624
Property, plant and equipment, net	$ 117	$ 101