Restructuring Costs (Details Textuals) (USD $)	3 Months Ended		9 Months Ended				9 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended																3 Months Ended	9 Months Ended					3 Months Ended	9 Months Ended			12 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2013 Performance Plus Program [Member]	Sep. 30, 2007 Performance Plus Program [Member]	Jun. 30, 2013 Segment Reorganization [Member]	Jun. 30, 2013 Segment Reorganization [Member]	Jun. 30, 2013 Remanufacturing Consolidation [Member]	Jun. 30, 2013 Remanufacturing Consolidation [Member]	Jun. 30, 2013 Hourly Positions [Member] Segment Reorganization [Member]	Jun. 30, 2013 Hourly Positions [Member] Remanufacturing Consolidation [Member]	Jun. 30, 2013 Hourly Positions [Member] Variable Labor Reductions [Member]	Jun. 30, 2013 Hourly Positions [Member] M2016 Strategy [Member]	Jun. 30, 2013 Hourly Positions Transferred [Member] Remanufacturing Consolidation [Member]	Jun. 30, 2013 High Range [Member] Segment Reorganization [Member]	Jun. 30, 2013 Low Range [Member] Segment Reorganization [Member]	Jun. 30, 2013 Salaried Position [Member] Segment Reorganization [Member]	Jun. 30, 2013 Salaried Position [Member] Variable Labor Reductions [Member]	Jun. 30, 2013 Salaried Position [Member] M2016 Strategy [Member]	Jun. 30, 2013 Corporate [Member] Segment Reorganization [Member]	Jun. 30, 2013 Asset Impairment [Member] Performance Plus Program [Member]	Jun. 30, 2013 Discontinued Operations [Member] Performance Plus Program [Member]	Jun. 30, 2013 Commercial Truck and Industrial [Member] Performance Plus Program [Member]	Jun. 30, 2013 Commercial Truck and Industrial [Member] Variable Labor Reductions [Member]	Jun. 30, 2013 Commercial Truck and Industrial [Member] M2016 Strategy [Member]	Jun. 30, 2013 Commercial Truck and Industrial [Member] M2016 Strategy [Member]	Jun. 30, 2013 Pension Termination Benefits [Member] Performance Plus Program [Member]	Jun. 30, 2013 Aftermarket and Trailer Segment [Member] Performance Plus Program [Member]	Jun. 30, 2013 Aftermarket and Trailer Segment [Member] Segment Reorganization [Member]	Jun. 30, 2013 Employee Severance [Member] Performance Plus Program [Member]	Dec. 31, 2011 Commercial Truck Segment [Member] Performance Plus Program [Member]	Jun. 30, 2012 Commercial Truck Segment [Member] Performance Plus Program [Member]	Jun. 30, 2013 Commercial Truck Segment [Member] Segment Reorganization [Member]	Jun. 30, 2013 Commercial Truck Segment [Member] Variable Labor Reductions [Member]	Sep. 30, 2012 Commercial Truck Segment [Member] Variable Labor Reductions [Member]	Jun. 30, 2012 Commercial Truck Segment [Member] 2012 European Actions [Member]	Jun. 30, 2012 Commercial Truck Segment [Member] 2012 European Actions [Member]	Dec. 31, 2011 St Priest [Member] Performance Plus Program [Member]
Restructuring Reserve	$ 24,000,000	$ 12,000,000	$ 24,000,000	$ 12,000,000	$ 15,000,000	$ 19,000,000
Expected Number Of Positions Eliminated								2,800					0	85,000,000	375,000,000	74,000,000	65,000,000			0	50,000,000	12,000,000
Restructuring and Related Cost, Expected Cost																		5,000,000	3,000,000								9,000,000		2,000,000
Cumulative Costs Incurred to Date							186,000,000			21,000,000													3,000,000	41,000,000	93,000,000	82,000,000		2,000,000		28,000,000	11,000,000	3,000,000	117,000,000			15,000,000	8,000,000
Restructuring Charges	12,000,000	3,000,000	29,000,000	30,000,000					9,000,000		1,000,000	3,000,000																							24,000,000		3,000,000	5,000,000	3,000,000	4,000,000	5,000,000
Restructuring Costs and Asset Impairment Charges			$ 1,000,000	$ 20,000,000																														$ (17,000,000)	$ (19,000,000)