Equity and Noncontrolling Interests Equity and Noncontrolling Interests - Additional Information (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	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value						$ 679
Treasury Stock, Value, Acquired, Cost Method	$ 307	$ 475	$ 426	$ 475
Stock repurchase program, amount estimated to be utilized	750
Post Merger Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount	1,000		1,000		$ 1,000
Parent [Member]
Equity, Class of Treasury Stock [Line Items]
Stockholder's equity, spin-off of Adient			4,038	0
Treasury Stock, Value, Acquired, Cost Method	$ 307	$ 475	$ 426	$ 475