Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (191)	$ 101	$ 295
Other comprehensive income, net of tax:
Foreign currency translation adjustments	(14)	204	(17)
Realized and unrealized gains (losses) on derivatives	37	(32)	21
Other comprehensive income	23	172	4
Total comprehensive income (loss)	(168)	273	299
Comprehensive income attributable to noncontrolling interests	88	106	91
Comprehensive income (loss) attributable to Adient	$ (256)	$ 167	$ 208