DOCUMENT AND ENTITY INFORMATION	6 Months Ended
	Mar. 31, 2012	Apr. 01, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	MERITOR INC
Entity Central Index Key	0001113256
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Trading Symbol	mtor
Entity Common Stock, Shares Outstanding		96,487,135
Document Period End Date	Mar. 31, 2012
Document Type	10-Q
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2012
Amendment Flag	false