Unaudited Condensed Consolidated Balance Sheet (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	225,571,921	224,665,395
Common stock, shares outstanding	217,097,274	222,955,853