BUSINESS SEGMENT INFORMATION - Schedule of Segment Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Total depreciation and amortization	$ 75	$ 67	$ 65
Total capital expenditures	95	93	79
TOTAL ASSETS	2,782	2,494
Commercial Truck & Industrial
Segment Reporting Information [Line Items]
Total depreciation and amortization	66	59	59
Total capital expenditures	85	83	71
Aftermarket & Trailer
Segment Reporting Information [Line Items]
Total depreciation and amortization	9	8	6
Total capital expenditures	10	10	8
Operating Segments
Segment Reporting Information [Line Items]
TOTAL ASSETS	2,174	1,869
Operating Segments | Commercial Truck & Industrial
Segment Reporting Information [Line Items]
TOTAL ASSETS	1,707	1,433
Operating Segments | Aftermarket & Trailer
Segment Reporting Information [Line Items]
TOTAL ASSETS	467	436
Corporate
Segment Reporting Information [Line Items]
TOTAL ASSETS	869	845
Segment Reconciling Items
Segment Reporting Information [Line Items]
Total depreciation and amortization	75	67	$ 65
Less: Accounts receivable sold under off-balance sheet factoring programs (2)	$ (261)	$ (220)