Property, Plant and Equipment - Leases (Details) - Buildings and improvements - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Property Subject to or Available for Operating Lease [Line Items]
Properties in gross building and improvements	$ 15	$ 36
Accumulated depreciation in gross buildings and improvements	$ 9	$ 28

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration