Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 295	$ (40)	$ 1,190
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(17)	(250)	16
Realized and unrealized gains (losses) on derivatives	21	0	20
Pension and postretirement plans	0	1	1
Other comprehensive income (loss)	4	(249)	37
Total comprehensive income (loss)	299	(289)	1,227
Comprehensive income (loss) attributable to noncontrolling interests	91	49	81
Comprehensive income (loss) attributable to Adient	$ 208	$ (338)	$ 1,146