CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Sales	$ 514	$ 1,166	$ 2,286	$ 3,360
Cost of sales	(486)	(987)	(2,017)	(2,866)
GROSS PROFIT	28	179	269	494
Selling, general and administrative	(52)	(73)	(181)	(180)
Income from WABCO distribution termination	0	0	265	0
Other operating expense, net	(17)	(2)	(32)	(1)
OPERATING INCOME (LOSS)	(41)	104	321	313
Other income, net	12	10	36	30
Equity in earnings of affiliates	(1)	9	11	24
Interest expense, net	(17)	(14)	(47)	(43)
INCOME (LOSS) BEFORE INCOME TAXES	(47)	109	321	324
Benefit (provision) for income taxes	13	(21)	(73)	(69)
INCOME (LOSS) FROM CONTINUING OPERATIONS	(34)	88	248	255
INCOME FROM DISCONTINUED OPERATIONS, net of tax	0	1	1	0
NET INCOME (LOSS)	(34)	89	249	255
Less: Net income attributable to noncontrolling interests	(2)	(3)	(5)	(7)
NET INCOME (LOSS) ATTRIBUTABLE TO MERITOR, INC.	(36)	86	244	248
NET INCOME (LOSS) ATTRIBUTABLE TO MERITOR, INC.
Net income (loss) from continuing operations	(36)	85	243	248
Income from discontinued operations	0	1	1	0
Net income (loss)	$ (36)	$ 86	$ 244	$ 248
BASIC EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	$ (0.50)	$ 1.02	$ 3.26	$ 2.96
Discontinued operations (in usd per share)	0	0.01	0.01	0
Basic earnings per share (in usd per share)	(0.50)	1.03	3.27	2.96
DILUTED EARNINGS (LOSS) PER SHARE
Continuing operations (in usd per share)	(0.50)	0.99	3.19	2.86
Discontinued operations (in usd per share)	0	0.01	0.01	0
Diluted earnings per share (in usd per share)	$ (0.50)	$ 1.00	$ 3.20	$ 2.86
Basic average common shares outstanding (in shares)	72.1	83.0	74.6	83.7
Diluted average common shares outstanding (in shares)	72.1	85.6	76.3	86.6