INVESTMENTS IN NON-CONSOLIDATED JOINT VENTURES - Investments In Non-Consolidated Joint Ventures (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Investments in non-consolidated joint ventures	$ 110	$ 102
Commercial Truck
Segment Reporting Information [Line Items]
Investments in non-consolidated joint ventures	110	102
Aftermarket, Industrial and Trailer
Segment Reporting Information [Line Items]
Investments in non-consolidated joint ventures	$ 0	$ 0