Fair Value Of Assets And Liabilities - Reconciliation Of Balance, Fair Value Measurement, Level 3 (Details) - Contingent consideration liability - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance (Liability)	$ (60.2)	$ (40.9)
Revision to purchase price allocation	5.5
Net unrealized gains and losses included in other gains and losses, net	8.2	(1.5)
Disposition/settlements	12.9	4.0
Ending balance (Liability)	$ (33.6)	$ (38.4)