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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income available to shareholders
Net income (loss) attributable to Adient	$ (11)	$ 73	$ (61)	$ 70
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	88.6	94.1	90.7	94.8
Stock options, unvested restricted stock and unvested performance share awards (in shares)	0.0	0.8	0.0	0.8
Diluted weight average shares outstanding (in shares)	88.6	94.9	90.7	95.6
Earnings (loss) per share:
Basic (in usd per share)	$ (0.12)	$ 0.78	$ (0.67)	$ 0.74
Diluted (in usd per share)	$ (0.12)	$ 0.77	$ (0.67)	$ 0.73