Segment Information - Schedule of Financial Information for Reportable Segments (Details) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	Nov. 30, 2023
Segment Reporting [Abstract]
Number of reportable segments | segment			3
Segment Reporting Information [Line Items]
Net sales	$ 3,750	$ 3,912	$ 7,410	$ 7,611
Adjusted EBITDA	227	215	443	427
Corporate-related costs	1	0	(6)	0
Restructuring and impairment costs	(125)	(17)	(136)	(24)
Purchase accounting amortization	(13)	(14)	(24)	(26)
Restructuring related charges	(2)	0	7	(3)
Impairment of interests in nonconsolidated partially owned affiliates	0	(7)	0	(6)
Depreciation	(70)	(71)	(142)	(140)
Equity based compensation	(10)	(10)	(23)	(18)
Earnings before interest and income taxes	8	96	119	210
Net financing charges	(47)	(59)	(91)	(100)
Other pension income (expense)	(2)	(2)	(4)	(11)
Income (loss) before income taxes	(41)	35	24	99
Gain on contract settlement			3	1
Stock based compensation	10	10	23	18
One-time divestiture related tax impact at an affiliate			2
Net actuarial and settlement/curtailment (gain) loss	0	0	0	8
Adient (Langfang) Seating Co., Ltd | Disposed of By Sale
Segment Reporting Information [Line Items]
Loss on disposal			8
Subsidiary, ownership percentage disposed					51.00%
Restatement Adjustment
Segment Reporting Information [Line Items]
Equity based compensation			(5)
Stock based compensation			5
Americas
Segment Reporting Information [Line Items]
Net sales	1,660	1,761	3,307	3,485
Gain on disposition of property plant equipment			10
Brazil
Segment Reporting Information [Line Items]
One-time gain	1		1
Adjusted EBITDA
Segment Reporting Information [Line Items]
Net actuarial and settlement/curtailment (gain) loss				8
EMEA
Segment Reporting Information [Line Items]
Impairment of nonconsolidated partially owned affiliates		3
Asia
Segment Reporting Information [Line Items]
Impairment of nonconsolidated partially owned affiliates		4
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA	249	238	488	473
Operating Segments | Adjusted EBITDA
Segment Reporting Information [Line Items]
Net sales	1,660	1,761	3,307	3,485
Adjusted EBITDA	80	72	160	141
Operating Segments | EMEA
Segment Reporting Information [Line Items]
Net sales	1,370	1,401	2,638	2,583
Adjusted EBITDA	57	53	102	81
Operating Segments | Asia
Segment Reporting Information [Line Items]
Net sales	742	774	1,512	1,595
Adjusted EBITDA	112	113	226	251
Corporate-related costs
Segment Reporting Information [Line Items]
Net sales	(22)	(24)	(47)	(52)
Adjusted EBITDA		(23)	(45)	(46)
Corporate-related costs	$ (22)	$ (23)	$ (45)	$ (46)