Acquisitions and Divestitures - Fair Value Allocation (Details) - USD ($) $ in Millions		1 Months Ended
	Sep. 22, 2017	Jul. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Goodwill			$ 2,150	$ 2,182	$ 2,515
Futuris
Business Acquisition [Line Items]
Cash and cash equivalents	$ 34
Accounts receivable	93
Inventory - net	41
Property, plant and equipment	53
Other assets	22
Goodwill	184
Identifiable intangibles	160
Accounts payable	(86)
Other liabilities	(118)
Total purchase consideration	383
Less: cash acquired	34
Net cash paid	349
Plus: acquired debt	4
Net purchase consideration	$ 353
GAAS
Business Acquisition [Line Items]
Cash and cash equivalents		$ 102
Accounts receivable		46
Inventory - net		2
Property, plant and equipment		17
Other assets		3
Goodwill		79
Identifiable intangibles		276
Accounts payable		(83)
Other liabilities		(88)
Total purchase consideration		354
Noncontrolling interest		(170)
Adient's interest		$ 184