Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserves against accounts receivable:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at beginning of period	$ (8.8)	$ (7.7)	$ (8.2)
(Charges) Income	(2.0)	(3.1)	(0.9)
Deductions from (increase to) reserves and other	1.1	2.0	1.4
Balance at end of period	(9.7)	(8.8)	(7.7)
Valuation allowances against deferred tax assets:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at beginning of period	(219.6)	(475.2)	(391.7)
(Charges) Income	25.2	257.6	(76.1)
Deductions from (increase to) reserves and other	(4.7)	(2.0)	(7.4)
Balance at end of period	$ (199.1)	$ (219.6)	$ (475.2)