Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Consolidated Balance Sheets
Allowance for doubtful accounts	$ 43.5	$ 44.8
Class A Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock shares authorized	2,000,000,000.0	1,000,000,000.0
Class A Common Stock, shares issued	600,700,000	600,700,000
Class A Common Stock, shares outstanding	599,100,000	598,700,000
Treasury stock, shares	1,600,000	2,000,000.0