Supplemental Equity and Comprehensive Income Information (Details 1) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Supplemental Equity and Comprehensive Income Information    
Common stock, par value per share (in dollars per share) $ 0.01 $ 0.01
Common stock, shares issued (in shares) 944,033,056 944,033,056
Treasury stock (in shares) 309,692,081 308,898,462