Equity and Noncontrolling Interests - Schedule of Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	$ 2,679	$ 1,797	$ 2,718	$ 1,535
Net income (loss)	(69)	87	(112)	254
Foreign currency translation adjustments	9	(30)	28	35
Realized and unrealized gains (losses) on derivatives	4	(11)	2	17
Dividends attributable to noncontrolling interests	(8)	(7)	(16)	(11)
Purchase of subsidiary shares from noncontrolling interest			0
Share based compensation and other	10	6	5	12
Stockholders' equity, ending balance	2,625	1,842	2,625	1,842
Adjustments from adoption of a new standard
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance		0		0
Shareholders' Equity Attributable to Adient
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	2,344	1,452	2,376	1,213
Net income (loss)	(81)	69	(135)	219
Foreign currency translation adjustments	8	(26)	25	29
Realized and unrealized gains (losses) on derivatives	4	(11)	2	17
Purchase of subsidiary shares from noncontrolling interest			12
Share based compensation and other	10	5	5	11
Stockholders' equity, ending balance	2,285	1,489	2,285	1,489
Shareholders' Equity Attributable to Adient | Adjustments from adoption of a new standard
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance		0		0
Ordinary Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	0	0	0	0
Stockholders' equity, ending balance	0	0	0	0
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	3,998	3,980	3,991	3,974
Purchase of subsidiary shares from noncontrolling interest			12
Share based compensation and other	10	5	5	11
Stockholders' equity, ending balance	4,008	3,985	4,008	3,985
Additional Paid-in Capital | Adjustments from adoption of a new standard
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance		0		0
Retained Earnings (Accumulated Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	(1,042)	(1,946)	(988)	(2,096)
Net income (loss)	(81)	69	(135)	219
Stockholders' equity, ending balance	(1,123)	(1,877)	(1,123)	(1,877)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	(612)	(582)	(627)	(665)
Foreign currency translation adjustments	8	(26)	25	29
Realized and unrealized gains (losses) on derivatives	4	(11)	2	17
Stockholders' equity, ending balance	(600)	(619)	(600)	(619)
Shareholders' Equity Attributable to Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance	335	345	342	322
Net income (loss)	12	18	23	35
Foreign currency translation adjustments	1	(4)	3	6
Dividends attributable to noncontrolling interests	(8)	(7)	(16)	(11)
Purchase of subsidiary shares from noncontrolling interest			(12)
Share based compensation and other	0	1	0	1
Stockholders' equity, ending balance	$ 340	$ 353	$ 340	$ 353