Leases - Operating lease liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Leases
Current operating lease liabilities	$ 96.4
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current
Long-term operating lease liabilities	$ 2,349.3	$ 2,350.3
Total operating lease liabilities	$ 2,445.7