Acquisitions and Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2011
Sale of Land in Mexico [Abstract]
First Installment received from the sale of land in Mexico				$ 24
Second Installment received from the sale of land in Mexico		36
Pretax costs related to sale of land	5		7
Aftertax costs related to sale of land	$ 3		$ 5