Basis of Presentation and Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income (loss) attributable to Adient	$ (149)	$ (168)	$ (166)	$ (384)
Denominator:
Weighted average shares outstanding (in shares)	93.5	93.4	93.5	93.3
Effect of dilutive securities (in shares)	0.0	0.0	0.0	0.0
Diluted shares (in shares)	93.5	93.4	93.5	93.3
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)