Leases - Components of Lease Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating lease income:
Variable lease income	$ 262.1	$ 254.1
Operating Lease, Variable Lease Income	16.8	14.8
Operating Lease, Lease Income	278.9	268.9
Finance lease income	1.7	1.8
Total lease income	280.6	270.7
Total operating lease income	$ 16.8	$ 22.7