Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Other investments	$ 2,526.6	$ 2,757.8
Class A
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	175,131,403	174,310,558
Common stock, outstanding (in shares)	175,131,403	174,310,558
Class B
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	12,994,000	12,930,839
Common stock, outstanding (in shares)	12,994,000	12,930,839
Class C
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	323,091,916	340,114,729
Common stock, outstanding (in shares)	323,091,916	340,114,729