Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Intangible Assets [Line Items]
Gross carrying amount, total intangible assets	$ 7,567	$ 7,511
Net, Total Intangible Assets	6,625	6,741
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	4,950	4,885
Accumulated Amortization	(942)	(770)
Net, Total Amortized Intangible Assets	4,008	4,115
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,617	2,626
Patented Technology
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	1,344	1,328
Accumulated Amortization	(205)	(137)
Net, Total Amortized Intangible Assets	1,139	1,191
Customer Relationships
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	3,163	3,168
Accumulated Amortization	(561)	(486)
Net, Total Amortized Intangible Assets	2,602	2,682
Miscellaneous
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	443	389
Accumulated Amortization	(176)	(147)
Net, Total Amortized Intangible Assets	267	242
Trademarks/trade names
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,494	2,483
Miscellaneous
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	$ 123	$ 143