Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, shares outstanding	93,100,515	94,704,173	95,997,693