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, 2021	Mar. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance (Liability)	$ (18.6)	$ (60.2)
Revision to purchase price allocation	0.0	5.5
Net unrealized gains and losses included in other gains and losses, net	5.7	8.2
Disposition/settlements	8.5	12.9
Ending balance (Liability)	$ (4.4)	$ (33.6)