RESTRUCTURING COSTS - Restructuring Expense Recognized By Segment (Details) - USD ($) $ in Millions	3 Months Ended						12 Months Ended			22 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 2	$ 4	$ 7	$ 6	$ 2	$ 1	$ 6	$ 16	$ 16
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2						0	2	2
Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs							2	6	14
Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs							4	8	0
Aftermarket actions
Restructuring Cost and Reserve [Line Items]
Restructuring costs							4	5
Aftermarket actions | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs							0	0
Aftermarket actions | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs							0	0
Aftermarket actions | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs							4	5
Aftermarket actions
Restructuring Cost and Reserve [Line Items]
Restructuring costs								8
Aftermarket actions | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs								2
Aftermarket actions | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs	5							5
Aftermarket actions | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 1							1
South America labor reduction II
Restructuring Cost and Reserve [Line Items]
Restructuring costs									6
South America labor reduction II | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
South America labor reduction II | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs									6
South America labor reduction II | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
M2016 footprint actions
Restructuring Cost and Reserve [Line Items]
Restructuring costs									5
M2016 footprint actions | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
M2016 footprint actions | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs									5	$ 7
M2016 footprint actions | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
Closure of engineering facility
Restructuring Cost and Reserve [Line Items]
Restructuring costs									2
Closure of engineering facility | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs									2
Closure of engineering facility | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
Closure of engineering facility | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
European labor reductions
Restructuring Cost and Reserve [Line Items]
Restructuring costs									2
European labor reductions | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
European labor reductions | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs									2
European labor reductions | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs									0
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs							2	3	1
Other | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs							0	0	0
Other | Commercial Truck & Industrial
Restructuring Cost and Reserve [Line Items]
Restructuring costs							2	1	1
Other | Aftermarket & Trailer
Restructuring Cost and Reserve [Line Items]
Restructuring costs							$ 0	$ 2	$ 0