Business Segment Information - Schedule of Segment Assets (Details) - USD ($) $ in Millions	Mar. 31, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Total assets	$ 2,536	$ 2,494
Operating Segments
Segment Reporting Information [Line Items]
Total assets	1,946	1,869
Operating Segments | Commercial Truck & Industrial
Segment Reporting Information [Line Items]
Total assets	1,506	1,433
Operating Segments | Aftermarket & Trailer
Segment Reporting Information [Line Items]
Total assets	440	436
Corporate
Segment Reporting Information [Line Items]
Total assets	825	845
Segment Reconciling Items
Segment Reporting Information [Line Items]
Less: Accounts receivable sold under off-balance sheet factoring programs	$ (235)	$ (220)