CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Sales	$ 920	$ 841	$ 2,425	$ 2,471
Cost of sales	(778)	(714)	(2,073)	(2,119)
GROSS MARGIN	142	127	352	352
Selling, general and administrative	(73)	(59)	(192)	(175)
Restructuring costs	0	(6)	(4)	(9)
Other operating expense, net	0	0	(5)	(3)
OPERATING INCOME (LOSS)	69	62	151	165
Other income (expense), net	1	0	1	(1)
Equity in earnings of affiliates	14	9	32	26
Interest expense, net	(21)	(20)	(63)	(63)
INCOME (LOSS) BEFORE INCOME TAXES	63	51	121	127
Provision for income taxes	(11)	(8)	(30)	(22)
INCOME FROM CONTINUING OPERATIONS	52	43	91	105
LOSS FROM DISCONTINUED OPERATIONS, net of tax	(1)	(1)	(1)	(4)
NET INCOME	51	42	90	101
Less: Net income attributable to noncontrolling interests	(3)	(1)	(5)	(2)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	48	41	85	99
NET INCOME ATTRIBUTABLE TO MERITOR, INC.
Net income from continuing operations	49	42	86	103
Loss from discontinued operations	(1)	(1)	(1)	(4)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	$ 48	$ 41	$ 85	$ 99
BASIC EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	$ 0.55	$ 0.47	$ 0.98	$ 1.13
Discontinued operations (in usd per share)	(0.01)	(0.01)	(0.01)	(0.04)
Basic earnings per share (in usd per share)	0.54	0.46	0.97	1.09
DILUTED EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	0.52	0.46	0.94	1.10
Discontinued operations (in usd per share)	(0.01)	(0.01)	(0.01)	(0.04)
Diluted earnings per share (in usd per share)	$ 0.51	$ 0.45	$ 0.93	$ 1.06
Basic average common shares outstanding (in shares)	88.4	89.8	87.9	91.2
Diluted average common shares outstanding (in shares)	93.3	92.0	91.4	93.1