Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Consolidated Balance Sheets [Abstract]
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	500,000,000	500,000,000	500,000,000
Common stock, shares issued (in shares)	96,755,530	96,254,903	96,046,057