Equity and Noncontrolling Interests - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Realized and unrealized gains (losses) on derivatives
Current period changes in fair value		$ (9)	$ 4	$ (13)	$ 6
Pension and postretirement plans
Other changes				0	1
Accumulated other comprehensive loss		(729)	(1,174)	(729)	(1,174)	$ (1,153)
Foreign Currency Translation Adjustments
Foreign currency translation adjustments
Balance at beginning of period		(1,007)	(1,032)	(1,152)	(1,047)
Aggregate adjustment for the period		268	(141)	(150)	(126)
Adient spin-off impact				563	0
Balance at end of period		(739)	(1,173)	(739)	(1,173)
Aggregate adjustment for period, tax effect		(5)	(5)	0	(4)
Adient spin-off impact, tax effect				0	0
Realized and Unrealized Gains (Losses) on Derivatives
Realized and unrealized gains (losses) on derivatives
Balance at beginning of period		14	(4)	4	(7)
Current period changes in fair value		(1)	(3)	6	(9)
Reclassification to income		(6)	9	(19)	18
Adient spin-off impact				16	0
Balance at end of period		7	2	7	2
Current period changes in fair value, tax effect		(1)	(1)	3	(2)
Reclassifcation to income, tax effect	[1]	(5)	1	(12)	5
Adient spin-off, tax effect				6	0
Realized and unrealized gains (losses) on marketable securities
Realized and unrealized gains (losses) on marketable securities
Balance at beginning of period		8	0	(1)	0
Current period changes in fair value		(3)	0	6	0
Balance at end of period		5	0	5	0
Current period changes in fair value, tax effect		1	0	1	0
Pension And Postretirement Plans
Pension and postretirement plans
Balance at beginning of period		(2)	(3)	(4)	(3)
Reclassification to income		0	0	0	(1)
Adient spin-off impact				2	0
Balance at end of period		(2)	(3)	(2)	(3)
Reclassification to income, tax effect	[2]	$ 0	$ 0	0	(1)
Adient spin-off, tax effect				0	0
Other changes, tax effect				$ 0	$ 0

[1] Refer to Note 16, "Derivative Instruments and Hedging Activities," of the notes to consolidated financial statements for disclosure of the line items on the consolidated statements of income affected by reclassifications from AOCI into income related to derivatives

[2] ** Refer to Note 11, "Pension and Postretirement Plans," of the notes to consolidated financial statements for disclosure of the components of the Company's net periodic benefit costs associated with its defined benefit pension and postretirement plans. For the three and nine months ended June 30, 2016, the amounts reclassified from AOCI into income for pension and postretirement plans were primarily recorded in selling, general and administrative expenses on the consolidated statements of income.