Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock, par value	$ 2.5	$ 2.5
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	218,900,000	218,900,000
Treasury stock, shares	45,500,000	44,700,000