Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 38.5	$ 34.7
Stockholders’ equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	319,600,000	318,800,000
Treasury stock, shares (in shares)	2,400,000	0