CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 43us-gaap_ProfitLoss	$ 3us-gaap_ProfitLoss	$ 73us-gaap_ProfitLoss	$ 16us-gaap_ProfitLoss
Foreign currency translation adjustments:
Attributable to Meritor, Inc.	(33)	10	(67)	0
Attributable to noncontrolling interest	0	0	(1)	0
Other reclassification adjustment	0	0	1	0
Pension and other postretirement benefit related adjustments	11	10	23	20
Unrealized gain (loss) on investments and foreign exchange contracts	0	2	(1)	2
Other comprehensive income (loss), net of tax	(22)	22	(45)	22
Total comprehensive income	21	25	28	38
Less: Comprehensive income attributable to noncontrolling interest	0	(2)	0	(4)
Comprehensive income attributable to Meritor, Inc.	$ 21us-gaap_ComprehensiveIncomeNetOfTax	$ 23us-gaap_ComprehensiveIncomeNetOfTax	$ 28us-gaap_ComprehensiveIncomeNetOfTax	$ 34us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to noncontrolling interests.

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