CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Common stock voting, par value (in dollars per share)	$ 0.0025	$ 0.0025
Common stock voting, shares authorized (in shares)	900,000,000	900,000,000
Common stock voting, shares issued (in shares)	259,046,646	258,840,350
Common stock voting, shares outstanding (in shares)	223,173,055	222,867,408
Treasury stock, shares (in shares)	35,873,591	35,972,942