Organization and Summary of Significant Accounting Policies - Schedule of Computation of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net income attributable to Adient	$ 20	$ 12
Denominator:
Shares outstanding (in shares)	92.9	95.1
Effect of dilutive securities (in shares)	0.7	0.8
Diluted shares (in shares)	93.6	95.9
Earnings per share:
Basic (in usd per share)	$ 0.22	$ 0.13
Diluted (in usd per share)	$ 0.21	$ 0.13