Consolidated Balance Sheets Parenthetical (Parentheticals) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 8.2	$ 5.9
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, authorized	100.0	100.0
Preferred stock, issued	0.0	0.0
Preferred stock, outstanding	0.0	0.0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000.0	1,000.0
Common stock, shares issued	158.0	160.3
Common stock, shares outstanding	158.0	160.3