Consolidated Statements of Income (Loss) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Statement of Financial Position [Abstract]
Net sales	$ 4,228	$ 4,596	$ 8,386	$ 8,800
Cost of sales	4,031	4,314	8,009	8,317
Gross profit	197	282	377	483
Selling, general and administrative expenses	168	193	346	389
Restructuring and impairment costs	113	315	144	315
Equity income (loss)	62	85	145	181
Earnings (loss) before interest and income taxes	(22)	(141)	32	(40)
Net financing charges	40	37	75	70
Other pension expense (income)	0	(7)	(2)	(8)
Income (loss) before income taxes	(62)	(171)	(41)	(102)
Income tax provision (benefit)	64	(28)	74	237
Net income (loss)	(126)	(143)	(115)	(339)
Income (loss) attributable to noncontrolling interests	23	25	51	45
Net income (loss) attributable to Adient	$ (149)	$ (168)	$ (166)	$ (384)
Earnings per share, Basic (in dollars per share)	$ (1.59)	$ (1.80)	$ (1.78)	$ (4.12)
Earnings per share, Diluted (in dollars per share)	$ (1.59)	$ (1.80)	$ (1.78)	$ (4.12)
Shares used in computing earnings per share, Basic (in shares)	93.5	93.4	93.5	93.3
Shares used in computing earnings per share, Diluted (in shares)	93.5	93.4	93.5	93.3