Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Condensed Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.5	$ 0.5
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	531,553,003	530,315,453
Treasury stock, shares	103,120,961	103,637,016