CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Current assets
Allowance for credit losses	$ 0.0	$ 0.0
Stockholders' equity
Treasury stock, shares (in shares)	42,700,000	42,300,000
Preferred Stock
Stockholders' equity
Preferred stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000.0	100,000,000.0
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	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 (in shares)	50,000,000.0	50,000,000.0
Common stock, shares issued (in shares)	0	0
Common stock, shares outstanding (in shares)	0	0
Common Stock
Stockholders' equity
Common stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	450,000,000.0	450,000,000.0
Common stock, shares issued (in shares)	140,500,000	139,200,000
Common stock, shares outstanding (in shares)	97,800,000	96,900,000