Equity and Noncontrolling Interests - Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	$ 2,546	$ 2,375
Net income	32	26
Foreign currency translation adjustments	134	95
Realized and unrealized gains on derivatives	9	25
Dividends attributable to noncontrolling interests	(4)	(4)
Repurchases of common stock	(100)
Share based compensation and other	(1)	(8)
Stockholders' equity, ending balance	2,616	2,509
Shareholders' Equity Attributable to Adient
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	2,228	2,073
Net income	20	12
Foreign currency translation adjustments	129	90
Realized and unrealized gains on derivatives	9	25
Repurchases of common stock	(100)
Share based compensation and other	(1)	(8)
Stockholders' equity, ending balance	2,285	2,192
Ordinary Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	0	0
Stockholders' equity, ending balance	0	0
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	3,973	4,026
Repurchases of common stock	(100)
Share based compensation and other	(1)	(8)
Stockholders' equity, ending balance	3,872	4,018
Retained Earnings (Accumulated Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	(903)	(1,108)
Net income	20	12
Stockholders' equity, ending balance	(883)	(1,096)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	(842)	(845)
Foreign currency translation adjustments	129	90
Realized and unrealized gains on derivatives	9	25
Stockholders' equity, ending balance	(704)	(730)
Shareholders' Equity Attributable to Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	318	302
Net income	12	14
Foreign currency translation adjustments	5	5
Dividends attributable to noncontrolling interests	(4)	(4)
Share based compensation and other	0	0
Stockholders' equity, ending balance	$ 331	$ 317