Acquisitions and Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2011	Jun. 30, 2013	Jun. 30, 2012
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	6		6		11	13
Aftertax costs related to sale of land	$ 4		$ 5		$ 7	$ 10