Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	683,494,944	683,494,944
Treasury stock, shares	137,281,399	122,524,448