Shareholders' Equity and Noncontrolling Interests, Stock Repurchase (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 27, 2021	Apr. 24, 2018	Oct. 26, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	May 21, 2021
Shareholders' Equity
Treasury stock retired (in dollars)				$ 0.0	$ 0.0	$ 0.0	$ 0.0
Payments for shares repurchased and retained in treasury (in dollars)				$ 170.9	$ 201.9	$ 491.0	$ 459.2
Class A Common Stock, par value (in dollars per share)				$ 0.001		$ 0.001
Class A Common Stock, shares authorized								2,000,000,000
Increase in common stock shares authorized								1,000,000,000
2021 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased (in dollars)	$ 2,000.0
Repurchase of stock program, period	3 years
Number of shares repurchased and retired				2,300,000		4,100,000
Payments for shares repurchased and retired (in dollars)				$ 170.9		$ 287.2
2018 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased (in dollars)		$ 2,000.0
Repurchase of stock program, period		3 years
Number of shares repurchased					3,700,000	3,100,000	9,100,000
Payments for shares repurchased (in dollars)					$ 201.9	$ 203.8	$ 459.2
Number of shares repurchased and retained in treasury						300,000	2,000,000.0
Payments for shares repurchased and retained in treasury (in dollars)						$ 19.8	$ 110.3
Number of shares repurchased and retired						2,800,000	7,100,000
Payments for shares repurchased and retired (in dollars)						$ 184.0	$ 348.9
Subsequent Event | 2021 Stock Repurchase Program
Shareholders' Equity
Number of shares repurchased and retained in treasury			600,000
Payments for shares repurchased and retained in treasury (in dollars)			$ 46.1
Value of shares remaining that may be repurchased under the stock repurchase program (in dollars)			$ 1,666.6