Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 101	$ 295	$ (40)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	204	(17)	(250)
Realized and unrealized gains (losses) on derivatives	(32)	21	0
Pension and postretirement plans	0	0	1
Other comprehensive income (loss)	172	4	(249)
Total comprehensive income (loss)	273	299	(289)
Comprehensive income (loss) attributable to noncontrolling interests	106	91	49
Comprehensive income (loss) attributable to Adient	$ 167	$ 208	$ (338)