Net Property (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Property at cost	$ 1,388	$ 1,382
Less: accumulated depreciation	(907)	(899)
Net property	481	483
Land and land improvements
Property, Plant and Equipment [Line Items]
Property at cost	30	29
Buildings
Property, Plant and Equipment [Line Items]
Property at cost	228	228
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property at cost	928	914
Company-owned tooling
Property, Plant and Equipment [Line Items]
Property at cost	136	130
Construction in progress
Property, Plant and Equipment [Line Items]
Property at cost	$ 66	$ 81

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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