Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 94	$ 2	$ 267	$ (140)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(35)	(141)	37	(82)
Realized and unrealized gains (losses) on derivatives	(11)	(62)	17	(47)
Other comprehensive income (loss)	(46)	(203)	54	(129)
Total comprehensive income (loss)	48	(201)	321	(269)
Comprehensive income (loss) attributable to noncontrolling interests	16	4	56	38
Comprehensive income (loss) attributable to Adient	$ 32	$ (205)	$ 265	$ (307)