Revenue - Contract Balances (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 250.4	$ 269.3
Short-term contract assets	0.4	1.0
Long-term contract assets	1.3	2.8
Short-term deferred revenue	481.6	467.5
Long-term deferred revenue	$ 13.7	$ 7.8