Unaudited Condensed Consolidated Balance Sheet (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	211,785,586	211,056,501
Common stock, shares outstanding	211,663,639	211,046,501