Business Segment Information (Details 1) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Interest expense, net	$ (38)	$ (22)	$ (78)	$ (97)
Provision for income taxes	(6)	(12)	(19)	(31)
Depreciation and amortization			(49)	(50)
Noncontrolling interests	(1)	0	(2)	(4)
Restructuring costs	(9)	0	(15)	(3)
Income from continuing operations attributable to Meritor, Inc.	15	237	86	250
Operating Segments
Segment Reporting Information [Line Items]
Segment EBITDA	89	83	257	238
Operating Segments | Commercial Truck & Industrial
Segment Reporting Information [Line Items]
Segment EBITDA	58	55	171	165
Operating Segments | Aftermarket & Trailer
Segment Reporting Information [Line Items]
Segment EBITDA	31	28	86	73
Segment Reconciling Items
Segment Reporting Information [Line Items]
Unallocated legacy and corporate costs, net	(2)	(1)	(4)	(4)
Antitrust settlement with Eaton, net of tax	0	208	0	208
Interest expense, net	(38)	(22)	(78)	(97)
Provision for income taxes	(6)	(12)	(19)	(31)
Depreciation and amortization	(17)	(17)	(49)	(50)
Noncontrolling interests	(1)	0	(2)	(4)
Loss on sale of receivables	(1)	(2)	(4)	(7)
Restructuring costs	$ (9)	$ 0	$ (15)	$ (3)