Shareholders' Equity and Noncontrolling Interests, Stock Repurchase (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 24, 2018	Jul. 21, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Shareholders' Equity
Treasury stock retired (in dollars)			$ 0.0	$ 0.0	$ 0.0	$ 0.0
Payments for shares repurchased (in dollars)			$ 0.0	$ 248.7	$ 257.2	$ 408.7
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			0	2,600,000	2,700,000	4,400,000
Payments for shares repurchased (in dollars)				$ 248.7	$ 257.2	$ 408.7
Number of treasury shares retired					2,700,000	3,400,000
Treasury stock retired (in dollars)					$ 257.2	$ 321.1
Number of shares repurchased and retained in treasury						1,000,000.0
Payments for shares repurchased (in dollars)						$ 87.6
Subsequent Event | 2018 Stock Repurchase Program
Shareholders' Equity
Number of shares repurchased and retained in treasury		0
Value of shares remaining that may be repurchased under the stock repurchase program (in dollars)		$ 587.9