Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]
Sales	$ 0	$ 7	$ 1	$ 22
Loss before income taxes	(2)	(3)	(1)	(9)
Benefit from income taxes	0	0	0	5
Loss from discontinued operations attributable to Meritor, Inc.	(2)	$ (3)	(1)	$ (4)
Discontinued operations, assets	4		4		$ 8
Discontinued operations, liabilities	$ 11		$ 11		$ 21