Segment Information - Other Reconciling Items (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net Sales		$ 16,526	$ 17,439	$ 16,213
Equity Income		275	(13)	522
Total Assets	$ 10,942	10,342	10,942
Depreciation		278	400	337
Amortization		40	47	21
Capital Expenditures		468	536	577
Impairment of nonconsolidated partially owned affiliate		0	358	0
Purchase accounting amortization		4	22	22
Gain on previously-held interest		0	0	151
YFAI
Segment Reporting Information [Line Items]
Impairment of nonconsolidated partially owned affiliate	358		358
Purchase accounting amortization		4	22	22
Restructuring charges		5	10	1
Impact of tax reform		2	8
Gain on previously-held interest				151
Operating segments | Americas
Segment Reporting Information [Line Items]
Net Sales		7,785	7,664	7,290
Equity Income		3	10	10
Total Assets	3,248	3,237	3,248
Depreciation		109	141	118
Amortization		14	12	1
Capital Expenditures		190	233	227
Operating segments | EMEA
Segment Reporting Information [Line Items]
Net Sales		6,675	7,436	7,044
Equity Income		13	12	11
Total Assets	3,066	2,716	3,066
Depreciation		126	204	174
Amortization		5	12	11
Capital Expenditures		237	267	267
Operating segments | Asia
Segment Reporting Information [Line Items]
Net Sales		2,337	2,659	2,129
Equity Income		270	363	373
Total Assets	3,598	3,416	3,598
Depreciation		43	45	36
Amortization		18	20	5
Capital Expenditures		41	36	56
Reconciling Items
Segment Reporting Information [Line Items]
Net Sales		(271)	(320)	(250)
Equity Income		(11)	(398)	128
Total Assets	$ 1,030	973	1,030
Depreciation		0	10	9
Amortization		3	3	4
Capital Expenditures		$ 0	$ 0	$ 27