Net Property (Details) - USD ($) $ in Millions	Dec. 31, 2021	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Property at cost	$ 1,548	$ 1,550
Less: accumulated depreciation	(1,040)	(1,033)
Net property	508	517
Land and land improvements
Property, Plant and Equipment [Line Items]
Property at cost	42	41
Buildings
Property, Plant and Equipment [Line Items]
Property at cost	230	231
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property at cost	1,049	1,051
Company-owned tooling
Property, Plant and Equipment [Line Items]
Property at cost	166	164
Construction in progress
Property, Plant and Equipment [Line Items]
Property at cost	$ 61	$ 63