Supplemental Guarantor Condensed Consolidating Financial Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	$ 41		$ 41
Sales
Total Sales	962	908	1,869	1,799
Cost of sales	(846)	(813)	(1,650)	(1,621)
GROSS MARGIN	116	95	219	178
Selling, general and administrative	(66)	(65)	(125)	(127)
Restructuring costs	(2)	(11)	(3)	(17)
Other operating expense	0	(1)	(1)	(2)
OPERATING INCOME (LOSS)	48	18	90	32
Other income (loss), net	0	0	0	0
Equity in earnings of affiliates	9	10	17	19
Interest expense, net	(48)	(25)	(75)	(54)
INCOME (LOSS) BEFORE INCOME TAXES	9	3	32	(3)
Provision for income taxes	(9)	(7)	(19)	(17)
Equity income from continuing operations of subsidiaries	0	0	0	0
INCOME (LOSS) FROM CONTINUING OPERATIONS	0	(4)	13	(20)
INCOME FROM DISCONTINUED OPERATIONS, net of tax	3	0	3	(5)
NET INCOME	3	(4)	16	(25)
Less: Net income attributable to noncontrolling interests	(2)	0	(4)	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	1	(4)	12	(25)
External Sales [Member]
Sales
Total Sales	962	908	1,869	1,799
Subsidiaries Sales [Member]
Sales
Total Sales	0	0	0	0
Parent [Member]
Sales
Total Sales	0	0	0	0
Cost of sales	(13)	(14)	(26)	(26)
GROSS MARGIN	(13)	(14)	(26)	(26)
Selling, general and administrative	(23)	(23)	(40)	(44)
Restructuring costs	(1)	(3)	(1)	(3)
Other operating expense		(1)	0	(2)
OPERATING INCOME (LOSS)	(37)	(41)	(67)	(75)
Other income (loss), net	39	39	39	35
Equity in earnings of affiliates	0	0	0	0
Interest expense, net	(54)	(32)	(88)	(69)
INCOME (LOSS) BEFORE INCOME TAXES	(52)	(34)	(116)	(109)
Provision for income taxes	0	0	0	0
Equity income from continuing operations of subsidiaries	50	30	125	89
INCOME (LOSS) FROM CONTINUING OPERATIONS	(2)	(4)	9	(20)
INCOME FROM DISCONTINUED OPERATIONS, net of tax	3	0	3	(5)
NET INCOME	1	(4)	12	(25)
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	1	(4)	12	(25)
Parent [Member] | External Sales [Member]
Sales
Total Sales	0	0	0	0
Parent [Member] | Subsidiaries Sales [Member]
Sales
Total Sales	0	0	0	0
Guarantors [Member]
Sales
Total Sales	387	388	733	776
Cost of sales	(331)	(335)	(632)	(680)
GROSS MARGIN	56	53	101	96
Selling, general and administrative	(22)	(21)	(45)	(41)
Restructuring costs	0	(3)	0	(6)
Other operating expense		0	(1)	0
OPERATING INCOME (LOSS)	34	29	55	49
Other income (loss), net	(8)	(13)	(8)	(13)
Equity in earnings of affiliates	6	5	12	10
Interest expense, net	8	8	17	16
INCOME (LOSS) BEFORE INCOME TAXES	40	29	76	62
Provision for income taxes	0	(1)	(2)	(3)
Equity income from continuing operations of subsidiaries	7	(4)	44	19
INCOME (LOSS) FROM CONTINUING OPERATIONS	47	24	118	78
INCOME FROM DISCONTINUED OPERATIONS, net of tax	3	0	3	(4)
NET INCOME	50	24	121	74
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	50	24	121	74
Guarantors [Member] | External Sales [Member]
Sales
Total Sales	354	355	666	709
Guarantors [Member] | Subsidiaries Sales [Member]
Sales
Total Sales	33	33	67	67
Non-Guarantors [Member]
Sales
Total Sales	624	573	1,233	1,127
Cost of sales	(551)	(517)	(1,089)	(1,019)
GROSS MARGIN	73	56	144	108
Selling, general and administrative	(21)	(21)	(40)	(42)
Restructuring costs	(1)	(5)	(2)	(8)
Other operating expense		0	0	0
OPERATING INCOME (LOSS)	51	30	102	58
Other income (loss), net	(31)	(26)	(31)	(22)
Equity in earnings of affiliates	3	5	5	9
Interest expense, net	(2)	(1)	(4)	(1)
INCOME (LOSS) BEFORE INCOME TAXES	21	8	72	44
Provision for income taxes	(9)	(6)	(17)	(14)
Equity income from continuing operations of subsidiaries	0	0	0	0
INCOME (LOSS) FROM CONTINUING OPERATIONS	12	2	55	30
INCOME FROM DISCONTINUED OPERATIONS, net of tax	3	0	3	(4)
NET INCOME	15	2	58	26
Less: Net income attributable to noncontrolling interests	(2)	0	(4)	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	13	2	54	26
Non-Guarantors [Member] | External Sales [Member]
Sales
Total Sales	608	553	1,203	1,090
Non-Guarantors [Member] | Subsidiaries Sales [Member]
Sales
Total Sales	16	20	30	37
Elims [Member]
Sales
Total Sales	(49)	(53)	(97)	(104)
Cost of sales	49	53	97	104
GROSS MARGIN	0	0	0	0
Selling, general and administrative	0	0	0	0
Restructuring costs	0	0	0	0
Other operating expense		0	0	0
OPERATING INCOME (LOSS)	0	0	0	0
Other income (loss), net	0	0	0	0
Equity in earnings of affiliates	0	0	0	0
Interest expense, net	0	0	0	0
INCOME (LOSS) BEFORE INCOME TAXES	0	0	0	0
Provision for income taxes	0	0	0	0
Equity income from continuing operations of subsidiaries	(57)	(26)	(169)	(108)
INCOME (LOSS) FROM CONTINUING OPERATIONS	(57)	(26)	(169)	(108)
INCOME FROM DISCONTINUED OPERATIONS, net of tax	(6)	0	(6)	8
NET INCOME	(63)	(26)	(175)	(100)
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	(63)	(26)	(175)	(100)
Elims [Member] | External Sales [Member]
Sales
Total Sales	0	0	0	0
Elims [Member] | Subsidiaries Sales [Member]
Sales
Total Sales	$ (49)	$ (53)	$ (97)	$ (104)