Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 953	$ 847
Accumulated depreciation	(455)	(427)
Net property, plant and equipment	498	420
Non-cash accruals	10	13
Depreciation (includes capital and financing leases)	52	49	$ 42
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	58	51
Buildings
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	348	292
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	475	442
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	72	62
Assets Held under Capital Leases
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	61	54
Accumulated depreciation	$ (11)	$ (7)