Supplemental Guarantor Condensed Consolidating Financial Statements (Details 1) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Statement Of Income Captions [Line Items]
Net income	$ 14	$ 234	$ 87	$ 250
Other comprehensive income (loss)	23	19	(22)	41
Total comprehensive income	37	253	65	291
Less: Comprehensive income attributable to noncontrolling interests	(1)	0	(1)	(4)
Comprehensive income attributable to Meritor, Inc.	36	253	64	287
Parent
Condensed Statement Of Income Captions [Line Items]
Net income	13	234	85	246
Other comprehensive income (loss)	23	19	(21)	41
Total comprehensive income	36	253	64	287
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Meritor, Inc.	36	253	64	287
Guarantors
Condensed Statement Of Income Captions [Line Items]
Net income	85	291	233	412
Other comprehensive income (loss)	30	(10)	(62)	0
Total comprehensive income	115	281	171	412
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Meritor, Inc.	115	281	171	412
Non-Guarantors
Condensed Statement Of Income Captions [Line Items]
Net income	30	30	90	88
Other comprehensive income (loss)	(15)	19	3	19
Total comprehensive income	15	49	93	107
Less: Comprehensive income attributable to noncontrolling interests	(1)	0	(1)	(4)
Comprehensive income attributable to Meritor, Inc.	14	49	92	103
Elims
Condensed Statement Of Income Captions [Line Items]
Net income	(114)	(321)	(321)	(496)
Other comprehensive income (loss)	(15)	(9)	58	(19)
Total comprehensive income	(129)	(330)	(263)	(515)
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to Meritor, Inc.	$ (129)	$ (330)	$ (263)	$ (515)