Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	533,797,490	530,315,453
Treasury stock, shares	126,451,604	103,637,016