Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 16.9	$ 12.3	$ 7.3
Charged/ (credited) to expense	7.1	9.5	2.6
Charged/(credited) to other accounts	0.2	(0.4)	5.0
Deductions from reserves	4.5	4.5	2.6
Balance at end of period	19.9	16.9	12.3
Valuation allowance-taxes
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	41.8	25.7	21.4
Charged/ (credited) to expense	16.2	27.4	4.3
Charged/(credited) to other accounts	0.0	0.0	0.0
Deductions from reserves	0.0	11.3	0.0
Balance at end of period	$ 58.0	$ 41.8	$ 25.7