CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 89	$ 67	$ 255	$ 93
Foreign currency translation adjustments:
Attributable to Meritor, Inc.	(6)	(52)	(3)	(46)
Attributable to noncontrolling interest	(1)	(2)	0	(1)
Pension and other postretirement benefit related adjustments	1	3	2	9
Unrealized gain (loss) on cash flow hedges	(2)	1	(2)	4
Other comprehensive loss, net of tax	(8)	(50)	(3)	(34)
Total comprehensive income	81	17	252	59
Less: Comprehensive income attributable to noncontrolling interest	(2)	(1)	(7)	(7)
Comprehensive income attributable to Meritor, Inc.	$ 79	$ 16	$ 245	$ 52