Basis of Presentation (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Proceeds from Interest Received	$ 1.8	$ 10.0
Accounts Receivable, Allowance for Credit Loss	135.1	145.5	$ 135.5	$ 144.3	$ 146.1		$ 73.0
Off-Balance Sheet, Credit Loss, Liability	3.2	3.5	$ 3.4	3.7	$ 2.3		$ 0.0
Deferred tax liability, net	(17.4)			(27.2)
Retained Earnings (Accumulated Deficit)	$ 1,026.9			962.1
Cumulative effect, period of adoption, adjusted balance
Off-Balance Sheet, Credit Loss, Liability		$ 2.3		$ 0.0		$ 0.0