Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets
Non-U.S. net operating loss carryforwards	$ 2	$ 2
State net operating loss carryforwards	19	19
Employee benefit obligations	98	86
Compensation accruals	21	21
Credit carryforwards	19	36
Other (d)	22	9
Valuation allowances	(2)	(7)
Net deferred tax assets	179	166
Deferred tax liabilities
Goodwill and other intangibles	9	3
Property, plant and equipment	46	23
Undistributed earnings	2	2
Total deferred tax liabilities	57	28
Total net deferred tax assets	122	$ 138
Other Noncurrent Liabilities
Operating Loss Carryforwards [Line Items]
Deferred tax liability included in deferred tax asset balance	1
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	4
Expiration Years 2020 Through 2033 | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2
Expiration Years 2022 Through 2037 | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 233