CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance for doubtful accounts	$ 7.8	$ 7.5
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares (in shares)	10,000,000.0	10,000,000.0
Preferred stock, issued shares (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1.25	$ 1.25
Common stock, authorized shares (in shares)	300,000,000.0	300,000,000.0
Common stock, issued shares (in shares)	189,300,000	189,300,000
Common stock, outstanding shares (in shares)	119,900,000	118,700,000
Treasury stock, shares (in shares)	68,800,000	70,000,000
Stock held by employee benefits trusts, shares (in shares)	600,000	600,000.0