Segment Information Geographic Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Geographic Area Information [Line Items]
Net Sales	$ 31,400	$ 30,172	$ 20,837
Long-Lived Assets (Year-end)	6,171	6,121	5,632
UNITED STATES
Geographic Area Information [Line Items]
Net Sales	14,625	14,495	9,633
Long-Lived Assets (Year-end)	3,216	3,155	2,880
CHINA
Geographic Area Information [Line Items]
Net Sales	2,166	2,046	1,620
Long-Lived Assets (Year-end)	766	535	484
Germany
Geographic Area Information [Line Items]
Net Sales	1,961	1,779	1,430
Long-Lived Assets (Year-end)	275	290	287
United Kingdom
Geographic Area Information [Line Items]
Net Sales	1,139	928	291
Long-Lived Assets (Year-end)	73	109	103
JAPAN
Geographic Area Information [Line Items]
Net Sales	1,903	1,816	1,805
Long-Lived Assets (Year-end)	209	180	188
Mexico
Geographic Area Information [Line Items]
Net Sales	909	840	639
Long-Lived Assets (Year-end)	531	489	457
Other European Countries
Geographic Area Information [Line Items]
Net Sales	3,005	2,860	1,817
Long-Lived Assets (Year-end)	442	542	448
Other Foreign
Geographic Area Information [Line Items]
Net Sales	5,692	5,408	3,602
Long-Lived Assets (Year-end)	$ 659	$ 821	$ 785