Leases - Lease expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease expense	$ 148.6	$ 140.6
Short-term lease expense	15.4	17.0
Variable lease expense	8.0	6.5
Total lease expense	$ 172.0	$ 164.1