Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 30, 2017
Intangible Assets [Line Items]
Gross carrying amount, total intangible assets	$ 7,443	$ 7,511
Net, Total Intangible Assets	6,424	6,741
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	4,874	4,885
Accumulated Amortization	(1,019)	(770)
Net, Total Amortized Intangible Assets	3,855	4,115
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,569	2,626
Patented Technology
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	1,326	1,328
Accumulated Amortization	(233)	(137)
Net, Total Amortized Intangible Assets	1,093	1,191
Customer Relationships
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	3,091	3,168
Accumulated Amortization	(605)	(486)
Net, Total Amortized Intangible Assets	2,486	2,682
Miscellaneous
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	457	389
Accumulated Amortization	(181)	(147)
Net, Total Amortized Intangible Assets	276	242
Trademarks/trade names
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,447	2,483
Miscellaneous
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	$ 122	$ 143