Leases - Cash flow information, weighted average remaining term and discount rate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 62.0	$ 56.5
Right-of-use assets obtained in exchange for operating lease liabilities	$ 47.5	$ 1.1
Weighted-average remaining lease term - operating leases	25 years		25 years
Weighted-average discount rate - operating leases	6.50%		6.40%