Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative effect, period of adoption, adjustment	Shareholders' Equity Attributable to Adient	Shareholders' Equity Attributable to Adient Cumulative effect, period of adoption, adjustment	Ordinary Shares, par value	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative effect, period of adoption, adjustment	Accumulated Other Comprehensive Income (Loss)	Shareholders' Equity Attributable to Noncontrolling Interests
Beginning balance at Sep. 30, 2018	$ 2,717		$ 2,392		$ 0	$ 3,951	$ (1,028)		$ (531)	$ 325
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(438)		(491)				(491)			53
Foreign currency translation adjustments	(38)		(35)						(35)	(3)
Realized and unrealized gains (losses) on derivatives	(1)		(1)						(1)
Employee retirement plans	(2)		(2)						(2)
Dividends declared	(26)		(26)				(26)
Dividends attributable to noncontrolling interests	(61)									(61)
Change in noncontrolling interest share	28									28
Share based compensation and other	10		11			11				(1)
Ending balance at Sep. 30, 2019	2,189	$ (4)	1,848	$ (4)	0	3,962	(1,545)	$ (4)	(569)	341
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(505)		(547)				(547)			42
Foreign currency translation adjustments	(65)		(76)						(76)	11
Realized and unrealized gains (losses) on derivatives	(20)		(20)						(20)
Employee retirement plans	0
Dividends attributable to noncontrolling interests	(54)									(54)
Change in noncontrolling interest share	(18)									(18)
Share based compensation and other	12		12			12
Ending balance at Sep. 30, 2020	1,535		1,213		0	3,974	(2,096)		(665)	322
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,165		1,108				1,108			57
Foreign currency translation adjustments	24		17						17	7
Realized and unrealized gains (losses) on derivatives	20		20						20
Employee retirement plans	1		1						1
Dividends attributable to noncontrolling interests	(42)									(42)
Change in noncontrolling interest share	(3)
Share based compensation and other	18		17			17				1
Ending balance at Sep. 30, 2021	$ 2,718		$ 2,376		$ 0	$ 3,991	$ (988)		$ (627)	$ 342