CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Sales	$ 871	$ 1,156	$ 1,772	$ 2,194
Cost of sales	(757)	(982)	(1,531)	(1,879)
GROSS PROFIT	114	174	241	315
Selling, general and administrative	(59)	(73)	(129)	(107)
Income from WABCO distribution termination	265	0	265	0
Other operating income (expense), net	(10)	1	(15)	1
OPERATING INCOME	310	102	362	209
Other income, net	14	9	24	20
Equity in earnings of affiliates	6	6	12	15
Interest expense, net	(16)	(15)	(30)	(29)
INCOME BEFORE INCOME TAXES	314	102	368	215
Provision for income taxes	(73)	(27)	(86)	(48)
INCOME FROM CONTINUING OPERATIONS	241	75	282	167
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, net of tax	1	(1)	1	(1)
NET INCOME	242	74	283	166
Less: Net income attributable to noncontrolling interests	(1)	(2)	(3)	(4)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	241	72	280	162
NET INCOME (LOSS) ATTRIBUTABLE TO MERITOR, INC.
Net income from continuing operations	240	73	279	163
Income (loss) from discontinued operations	1	(1)	1	(1)
Net income	$ 241	$ 72	$ 280	$ 162
BASIC EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	$ 3.27	$ 0.88	$ 3.68	$ 1.94
Discontinued operations (in usd per share)	0.01	(0.01)	0.01	(0.01)
Basic earnings per share (in usd per share)	3.28	0.87	3.69	1.93
DILUTED EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	3.19	0.85	3.58	1.88
Discontinued operations (in usd per share)	0.01	(0.01)	0.01	(0.01)
Diluted earnings per share (in usd per share)	$ 3.20	$ 0.84	$ 3.59	$ 1.87
Basic average common shares outstanding (in shares)	73.4	83.3	75.8	84.0
Diluted average common shares outstanding (in shares)	75.3	85.6	78.0	86.6