Goodwill and Other Intangibles - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 1,518	$ 1,522
Accumulated amortization	(752)	(712)
Net carrying amount	766	810
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Gross carrying amount	1,796	1,800
Net carrying amount	1,044	1,088
Trademarks and Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	66	66
Accumulated amortization	(30)	(29)
Net carrying amount	36	37
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-lived intangible assets	278	278
Intellectual Property [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	710	712
Accumulated amortization	(413)	(391)
Net carrying amount	297	321
Customer and Supplier Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	742	744
Accumulated amortization	(309)	(292)
Net carrying amount	$ 433	$ 452