Acquisition of Business - Pro Forma Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Combination and Asset Acquisition [Abstract]
Total Revenues	$ 1,455.4	$ 1,449.9	$ 4,406.3	$ 4,094.0
Total Expenses	1,583.6	1,293.5	4,484.9	3,685.9
Net Income	(128.2)	156.4	(78.6)	408.1
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations, Net of Tax	$ (74.1)	$ 127.4	$ 0.1	$ 331.6