Business Segment Information (Details 1) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Segment Reporting Information [Line Items]        
Segment EBITDA $ 87 $ 81 [1] $ 168 $ 155
Unallocated legacy and corporate costs, net 0 [2] (1) [1],[2] (2) [2] (3) [2]
Interest expense, net (21) (48) [1] (40) (75)
Provision for income taxes (6) (8) [1] (13) (19)
Depreciation and amortization (17) (17) [1] (32) (33)
Noncontrolling interests 0 (2) [1] (1) (4)
Loss on sale of receivables (1) (2) [1] (3) (5)
Restructuring costs (3) (2) [1] (6) (3)
Income (loss) from continuing operations attributable to Meritor, Inc. 39 1 [1] 71 13
Commercial Truck & Industrial        
Segment Reporting Information [Line Items]        
Segment EBITDA 57 57 [1] 113 110
Aftermarket & Trailer        
Segment Reporting Information [Line Items]        
Segment EBITDA $ 30 $ 24 [1] $ 55 $ 45
[1] Amounts for prior periods have been recast for discontinued operations.
[2] Unallocated legacy and corporate costs, net represents items that are not directly related to the company's business segments. These costs primarily include asbestos-related charges, pension and retiree medical costs associated with sold businesses and other legacy costs for environmental and product liability.