Revenues, Unbilled Revenue and Deferred Revenue (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Contracts with Customers, Assets and Liabilities [Abstract]
Unbilled revenue	$ 70.5	$ 17.6
Deferred revenue	342.7	$ 314.9
Other Current Assets [Member]
Contracts with Customers, Assets and Liabilities [Abstract]
Unbilled revenue (current amount)	70.5
Other Current Liabilities [Member]
Contracts with Customers, Assets and Liabilities [Abstract]
Deferred revenue (current amount)	134.0
Other Liabilities [Member]
Contracts with Customers, Assets and Liabilities [Abstract]
Deferred revenue (noncurrent)	$ 208.7