Goodwill (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Mar. 31, 2012
Balance at September 30, 2011	$ 431
Foreign currency translation	2
Balance at March 31, 2012	433
Commercial Truck [Member]
Balance at September 30, 2011	150
Foreign currency translation	2
Balance at March 31, 2012	152
Industrial [Member]
Balance at September 30, 2011	109
Foreign currency translation	0
Balance at March 31, 2012	109
Aftermarket and Trailer [Member]
Balance at September 30, 2011	172
Foreign currency translation	0
Balance at March 31, 2012	$ 172