Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified		6 Months Ended		0 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Roxarsone (3-Nitro) [Member] plaintiffs claims	Jun. 30, 2013 PregSure [Member] claims	Aug. 13, 2013 Ulianopolis, Brazil [Member] plaintiffs defendant	Feb. 29, 2012 Ulianopolis, Brazil [Member] defendant	Jun. 30, 2013 Mary Green [Member] Roxarsone (3-Nitro) [Member] claims	Jun. 30, 2013 Euro Member Countries, Euro	Jun. 30, 2013 United States of America, Dollars
Loss Contingencies [Line Items]
Number of claims seeking damages		9	80		6	1
Number of plaintiffs		140		30
Number of claims settled			20
Number of additional defendants				57	5
Loss Contingency Accrual, Period Increase (Decrease)	$ 14						$ 11	$ 14
Loss Contingency, Receivable, Current	$ 14