Acquisitions and Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2013	Sep. 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	3	7		14	20
Aftertax costs related to sale of land	$ 2	$ 5		$ 9	$ 15