Equity and Noncontrolling Interests Equity and Noncontrolling Interests - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value					$ 679
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
Parent [Member]
Equity, Class of Treasury Stock [Line Items]
Stockholder's equity, spin-off of Adient	$ 18	$ 0	$ 4,038	$ 0