Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at beginning of period	$ 97.9	$ 86.7	$ 83.6
Charges to cost and expense	59.2	61.7	42.8
Other additions	0.0	0.0	0.0
(Deductions)	(51.9)	(50.5)	(39.7)
Balance at end of period	105.2	97.9	86.7
Allowance for Credit Losses [Member]
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at beginning of period	10.1	16.3	8.2
Charges to cost and expense	12.1	1.7	8.6
Other additions	0.0	0.0	0.0
(Deductions)	(1.7)	(7.9)	(0.5)
Balance at end of period	20.5	10.1	16.3
Unbilled Receivable Allowance [Member]
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at beginning of period	31.3	22.0	27.2
Charges to cost and expense	38.5	49.7	33.0
Other additions	0.0	0.0	0.0
(Deductions)	(39.4)	(40.4)	(38.2)
Balance at end of period	30.4	31.3	22.0
Valuation Allowance for Inventory [Member]
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at beginning of period	7.7	7.8	7.7
Charges to cost and expense	1.8	2.1	1.1
Other additions	0.0	0.0	0.0
(Deductions)	(1.0)	(2.2)	(1.0)
Balance at end of period	8.5	7.7	7.8
Valuation Allowance for Deferred Tax Assets [Member]
Schedule II - Valuation and Qualifying Accounts [Roll Forward]
Balance at beginning of period	48.8	40.6	40.5
Charges to cost and expense	6.8	8.2	0.1
Other additions	0.0	0.0	0.0
(Deductions)	(9.8)	0.0	0.0
Balance at end of period	$ 45.8	$ 48.8	$ 40.6