Contract Assets and Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Contract assets - current	$ 47.8		$ 47.8		$ 44.3
Contract assets - long-term	14.2		14.2		20.7
Deferred revenue - current	(242.0)		(242.0)		(257.1)
Deferred revenue - long-term	(143.3)		(143.3)		$ (137.9)
Revenue recognized that was included in deferred revenue at the beginning of the period	$ 63.8	$ 68.2	$ 162.9	$ 149.2