Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2011
Proceeds from Interest Received	$ (1.1)	$ (0.4)
Accounts Receivable, Allowance for Credit Loss	136.6	129.1	$ 144.3	$ 73.0	$ 144.3
Off-Balance Sheet, Credit Loss, Liability	3.4	$ 2.1	3.7	0.0
Deferred tax liability, net	(19.9)		(27.2)
Retained Earnings (Accumulated Deficit)	$ 988.2		962.1
Cumulative effect, period of adoption, adjusted balance
Off-Balance Sheet, Credit Loss, Liability			$ 0.0	$ 2.3