Goodwill and Other Intangible Assets Other Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Intangible Assets [Line Items]
Future amortization expense, 2017	$ 465
Gross carrying amount, total intangible assets	8,119	$ 1,904
Net, Total Intangible Assets	7,653	1,516
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	5,414	1,362
Accumulated Amortization	(466)	(388)
Net, Total Amortized Intangible Assets	4,948	974
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,705	542
Patented Technology
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	1,556	80
Accumulated Amortization	(37)	(59)
Net, Total Amortized Intangible Assets	1,519	21
Customer Relationships
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	3,268	975
Accumulated Amortization	(274)	(206)
Net, Total Amortized Intangible Assets	2,994	769
Miscellaneous
Finite-Lived Intangible Assets, Gross [Abstract]
Gross Carrying Amount	590	307
Accumulated Amortization	(155)	(123)
Net, Total Amortized Intangible Assets	435	184
Trademarks
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	2,555	542
Miscellaneous
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Carrying Amount, Gross and Net	150	$ 0
Adient spin-off [Member]
Intangible Assets [Line Items]
Future amortization expense, 2017	$ 430