DOCUMENT AND ENTITY INFORMATION - shares	6 Months Ended
	Mar. 31, 2017	May 02, 2017
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		88,570,671
Document period end date	Mar. 31, 2017
Document fiscal year focus	2017
Document type	10-Q
Document fiscal period focus	Q2
Amendment flag	false