Leases - Operating lease liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 02, 2019
Leases
Current operating lease liabilities	$ 91.0
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current
Long-term operating lease liabilities	$ 2,301.2	$ 2,387.5
Total operating lease liabilities	$ 2,392.2
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent us-gaap:OperatingLeaseLiabilityNoncurrent