CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Sales	$ 806	$ 821	$ 1,505	$ 1,630
Cost of sales	(685)	(700)	(1,295)	(1,405)
GROSS MARGIN	121	121	210	225
Selling, general and administrative	(66)	(60)	(119)	(116)
Restructuring costs	(4)	(2)	(4)	(3)
Other operating expense, net	(2)	(3)	(5)	(3)
OPERATING INCOME	49	56	82	103
Other expense, net	0	(2)	0	(1)
Equity in earnings of affiliates	8	7	18	17
Interest expense, net	(21)	(21)	(42)	(43)
INCOME BEFORE INCOME TAXES	36	40	58	76
Provision for income taxes	(13)	(7)	(19)	(14)
INCOME (LOSS) FROM CONTINUING OPERATIONS	23	33	39	62
LOSS FROM DISCONTINUED OPERATIONS, net of tax	0	(1)	0	(3)
NET INCOME	23	32	39	59
Less: Net income attributable to noncontrolling interests	(1)	0	(2)	(1)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	22	32	37	58
NET INCOME ATTRIBUTABLE TO MERITOR, INC.
Net income from continuing operations	22	33	37	61
Loss from discontinued operations	0	(1)	0	(3)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	$ 22	$ 32	$ 37	$ 58
BASIC EARNINGS (LOSS) PER SHARE
Continuing operations (in dollars per share)	$ 0.25	$ 0.36	$ 0.42	$ 0.66
Discontinued operations (in dollars per share)	0.00	(0.01)	0.00	(0.03)
Basic earnings per share (in dollars per share)	0.25	0.35	0.42	0.63
DILUTED EARNINGS (LOSS) PER SHARE
Continuing operations (in dollars per share)	0.24	0.36	0.41	0.65
Discontinued operations (in dollars per share)	0.00	(0.01)	0.00	(0.03)
Diluted earnings per share (in dollars per share)	$ 0.24	$ 0.35	$ 0.41	$ 0.62
Basic average common shares outstanding (in shares)	88.2	91.3	87.7	91.9
Diluted average common shares outstanding (in shares)	92.0	92.5	90.2	93.5