Supplemental Guarantor Condensed Consolidating Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	$ 29		$ 29
Sales
Total Sales	909	$ 979	2,652	$ 2,833
Cost of sales	(785)	(855)	(2,298)	(2,486)
GROSS MARGIN	124	124	354	347
Selling, general and administrative	(65)	(53)	(187)	(178)
Restructuring costs	(9)	0	(15)	(3)
Other operating income (expense), net	1	(1)	2	(2)
OPERATING INCOME (LOSS)	51	70	154	164
Other income (expense), net	(1)	0	3	0
Equity in earnings of ZF Meritor	0	190	0	190
Equity in earnings of other affiliates	10	11	28	28
Equity in earnings of affiliates	10		28	28
Interest income (expense), net	(38)	(22)	(78)	(97)
INCOME BEFORE INCOME TAXES	22	249	107	285
Provision for income taxes	(6)	(12)	(19)	(31)
Equity income from continuing operations of subsidiaries	0	0	0	0
INCOME FROM CONTINUING OPERATIONS	16	237	88	254
LOSS FROM DISCONTINUED OPERATIONS, net of tax	(2)	(3)	(1)	(4)
NET INCOME	14	234	87	250
Less: Net income attributable to noncontrolling interests	(1)	0	(2)	(4)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	13	234	85	246
External Sales
Sales
Total Sales	909	979	2,652	2,833
Subsidiaries Sales
Sales
Total Sales	0	0	0	0
Parent
Sales
Total Sales	0	0	0	0
Cost of sales	(14)	(14)	(38)	(40)
GROSS MARGIN	(14)	(14)	(38)	(40)
Selling, general and administrative	(20)	(28)	(54)	(68)
Restructuring costs	0		(1)	(1)
Other operating income (expense), net	(2)	0	(2)	0
OPERATING INCOME (LOSS)	(36)	(42)	(95)	(109)
Other income (expense), net	10	13	47	52
Equity in earnings of ZF Meritor		0		0
Equity in earnings of other affiliates		0		0
Equity in earnings of affiliates	0		0
Interest income (expense), net	(47)	(31)	(105)	(119)
INCOME BEFORE INCOME TAXES	(73)	(60)	(153)	(176)
Provision for income taxes	(1)	(1)	(2)	(1)
Equity income from continuing operations of subsidiaries	89	298	241	427
INCOME FROM CONTINUING OPERATIONS	15	237	86	250
LOSS FROM DISCONTINUED OPERATIONS, net of tax	(2)	(3)	(1)	(4)
NET INCOME	13	234	85	246
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	13	234	85	246
Parent | External Sales
Sales
Total Sales	0	0	0	0
Parent | Subsidiaries Sales
Sales
Total Sales	0	0	0	0
Guarantors
Sales
Total Sales	495	423	1,377	1,146
Cost of sales	(416)	(355)	(1,167)	(978)
GROSS MARGIN	79	68	210	168
Selling, general and administrative	(29)	(4)	(83)	(49)
Restructuring costs	(2)		(5)	0
Other operating income (expense), net	0	0	0	(1)
OPERATING INCOME (LOSS)	48	64	122	118
Other income (expense), net	(6)	(6)	(15)	(14)
Equity in earnings of ZF Meritor		190		190
Equity in earnings of other affiliates		9		21
Equity in earnings of affiliates	9		24
Interest income (expense), net	7	11	20	28
INCOME BEFORE INCOME TAXES	58	268	151	343
Provision for income taxes	0	(1)	0	(2)
Equity income from continuing operations of subsidiaries	28	27	81	75
INCOME FROM CONTINUING OPERATIONS	86	294	232	416
LOSS FROM DISCONTINUED OPERATIONS, net of tax	(1)	(3)	1	(4)
NET INCOME	85	291	233	412
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	85	291	233	412
Guarantors | External Sales
Sales
Total Sales	461	382	1,282	1,039
Guarantors | Subsidiaries Sales
Sales
Total Sales	34	41	95	107
Non-Guarantors
Sales
Total Sales	467	614	1,422	1,840
Cost of sales	(408)	(544)	(1,240)	(1,621)
GROSS MARGIN	59	70	182	219
Selling, general and administrative	(16)	(21)	(50)	(61)
Restructuring costs	(7)		(9)	(2)
Other operating income (expense), net	3	(1)	4	(1)
OPERATING INCOME (LOSS)	39	48	127	155
Other income (expense), net	(5)	(7)	(29)	(38)
Equity in earnings of ZF Meritor		0		0
Equity in earnings of other affiliates		2		7
Equity in earnings of affiliates	1		4
Interest income (expense), net	2	(2)	7	(6)
INCOME BEFORE INCOME TAXES	37	41	109	118
Provision for income taxes	(5)	(10)	(17)	(28)
Equity income from continuing operations of subsidiaries	0	0	0	0
INCOME FROM CONTINUING OPERATIONS	32	31	92	90
LOSS FROM DISCONTINUED OPERATIONS, net of tax	(2)	(1)	(2)	(2)
NET INCOME	30	30	90	88
Less: Net income attributable to noncontrolling interests	(1)	0	(2)	(4)
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	29	30	88	84
Non-Guarantors | External Sales
Sales
Total Sales	448	597	1,370	1,794
Non-Guarantors | Subsidiaries Sales
Sales
Total Sales	19	17	52	46
Elims
Sales
Total Sales	(53)	(58)	(147)	(153)
Cost of sales	53	58	147	153
GROSS MARGIN	0	0	0	0
Selling, general and administrative	0	0	0	0
Restructuring costs	0		0	0
Other operating income (expense), net	0	0	0	0
OPERATING INCOME (LOSS)	0	0	0	0
Other income (expense), net	0	0	0	0
Equity in earnings of ZF Meritor		0		0
Equity in earnings of other affiliates		0		0
Equity in earnings of affiliates	0		0
Interest income (expense), net	0	0	0	0
INCOME BEFORE INCOME TAXES	0	0	0	0
Provision for income taxes	0	0	0	0
Equity income from continuing operations of subsidiaries	(117)	(325)	(322)	(502)
INCOME FROM CONTINUING OPERATIONS	(117)	(325)	(322)	(502)
LOSS FROM DISCONTINUED OPERATIONS, net of tax	3	4	1	6
NET INCOME	(114)	(321)	(321)	(496)
Less: Net income attributable to noncontrolling interests	0	0	0	0
NET INCOME ATTRIBUTABLE TO MERITOR, INC.	(114)	(321)	(321)	(496)
Elims | External Sales
Sales
Total Sales	0	0	0	0
Elims | Subsidiaries Sales
Sales
Total Sales	$ (53)	$ (58)	$ (147)	$ (153)