Discontinued Operations Discontinued Operations, Income Statement Disclosures (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Oct. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Adient shares received per 10 shares of Johnson Controls shares							1
Johnson Controls shares converted into one share of Adient							10
Income from discontinued operations attributable to noncontrolling interests	$ 0		$ 0		$ 0	$ 9
Loss from discontinued operations	$ 0		0		$ 0	$ (43)
U.S. federal statutory income tax rate		21.00%				35.00%
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount			$ 8	$ 46
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales						$ 1,434
Income from discontinued operations before income taxes						1
Provision for income taxes on discontinued operations						35
Income from discontinued operations attributable to noncontrolling interests						9
Loss from discontinued operations						(43)
Separation costs						$ 79