Stock-Based Compensation - Stock Appreciation Rights (Details) - Stock appreciation rights (SARs) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares
Weighted Average SAR Price
Outstanding, beginning period (in dollars per share)	$ 33.29
Exercised (in dollars per share)	25.84
Forfeited or expired (in dollars per share)	27.50
Outstanding, ending period (in dollars per share)	43.87
Shares exercisable, weighted average exercise price (in dollars per share)	$ 43.87
Shares Subject to SAR
Shares outstanding at beginning of period (In shares) | shares	42,454
Exercised (in shares) | shares	(56,457)
Forfeited or expired (In shares) | shares	(4,973)
Shares outstanding at ending of period (In shares) | shares	103,884
Shares exercisable (in shares) | shares	42,454
Weighted Average Remaining Contractual Life (years)
Outstanding	2 years
Exercisable	2 years
Aggregate Intrinsic Value (in millions)
Outstanding | $	$ 0
Exercisable | $	$ 0
Former Parent plan
Weighted Average SAR Price
Shares exercisable, weighted average exercise price (in dollars per share)	$ 43.94
Shares Subject to SAR
Shares exercisable (in shares) | shares	37,705
Weighted Average Remaining Contractual Life (years)
Exercisable	2 years
Aggregate Intrinsic Value (in millions)
Exercisable | $	$ 0
Adient plan
Weighted Average SAR Price
Shares exercisable, weighted average exercise price (in dollars per share)	$ 43.25
Shares Subject to SAR
Shares exercisable (in shares) | shares	4,749
Weighted Average Remaining Contractual Life (years)
Exercisable	1 year 7 months 6 days
Aggregate Intrinsic Value (in millions)
Exercisable | $	$ 0
Former Parent and Adient plan
Weighted Average SAR Price
Shares exercisable, weighted average exercise price (in dollars per share)	$ 43.87