Balance Sheet Parenthetical (Parentheticals) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Apr. 02, 2017	Apr. 01, 2017
Current assets
Accounts Receivable, Allowance for Credit Loss, Current	$ 0.0	$ 4.4
Stockholders' equity
Preferred Stock, shares authorized	100.0
Preferred Stock, shares outstanding (in shares)	0.0	0.0		13.5	13.5		30.0
Common stock, shares outstanding (in shares)	96.9	110.4			105.2		70.9
Treasury Stock, shares	42.3	27.3
Preferred Stock
Stockholders' equity
Preferred Stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized	100.0	50.0
Preferred Stock, shares issued (in shares)	0.0	0.0
Preferred Stock, shares outstanding (in shares)	0.0	0.0
Series Common Stock
Stockholders' equity
Common Stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	50.0	50.0
Common Stock, shares issued (in shares)	0.0	0.0
Common stock, shares outstanding (in shares)	0.0	0.0
Common Stock
Stockholders' equity
Common Stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	450.0	450.0
Common Stock, shares issued (in shares)	139.2	137.7
Common stock, shares outstanding (in shares)	96.9	110.4
Convertible Preferred Stock
Stockholders' equity
Preferred Stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized	0.0	50.0				50.0
Preferred Stock, shares issued (in shares)	0.0	30.0	30.0
Preferred Stock, shares outstanding (in shares)	0.0	13.5