Note 5. Goodwill and Other Intangible Assets Intangible asset amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 656	$ 199
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	49
Finite-Lived Intangible Assets, Amortization Expense, Year Two	49
Finite-Lived Intangible Assets, Amortization Expense, Year Three	47
Finite-Lived Intangible Assets, Amortization Expense, Year Four	46
Finite-Lived Intangible Assets, Amortization Expense, Year Five	41
Finite-Lived Intangible Assets, Accumulated Amortization	113	86
Intangible Assets, Net (Excluding Goodwill)	543	113
Amortization of Intangible Assets	21	17	$ 18
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	30	28
Finite-Lived Intangible Assets, Accumulated Amortization	15	13
Intangible Assets, Net (Excluding Goodwill)	15	15
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	545	100
Finite-Lived Intangible Assets, Accumulated Amortization	64	48
Intangible Assets, Net (Excluding Goodwill)	481	52
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	59	56
Finite-Lived Intangible Assets, Accumulated Amortization	26	19
Intangible Assets, Net (Excluding Goodwill)	33	37
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	22	15
Finite-Lived Intangible Assets, Accumulated Amortization	8	6
Intangible Assets, Net (Excluding Goodwill)	$ 14	$ 9