Unaudited Condensed Consolidated Balance Sheet (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Stockholders' Equity:
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	201,520,963	200,859,676
Common stock, shares outstanding	194,147,675	195,772,876