Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Condensed Consolidated Balance Sheets
Common stock, par value	$ 0.5	$ 0.5
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	530,126,658	525,817,549
Treasury stock, shares	103,641,547	89,707,087