Leases - Lease Maturity (Details) $ in Millions	Mar. 31, 2020 USD ($)
Lease Maturity [Abstract]
Less: current portion of long-term lease liability as of September 30, 2019	$ 83
Long-term lease liability as of September 30, 2019	$ 86

Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

Name:	us-gaap_OperatingLeaseLiabilityNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant