Leases Maturities of lease liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2019		Jan. 01, 2019	Dec. 31, 2018
Maturities of lease liabilities [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		$ 305.3
Operating Leases, Future Minimum Payments Due, Next Twelve Months					$ 329.8
Operating Leases, Future Minimum Payments, Due in Two Years					286.1
Operating Leases, Future Minimum Payments, Due in Three Years					192.3
Operating Leases, Future Minimum Payments, Due in Four Years					123.8
Operating Leases, Future Minimum Payments, Due in Five Years					102.1
Lessee, Operating Lease, Liability, Payments, Due Year Two		184.6
Lessee, Operating Lease, Liability, Payments, Due Year Three		128.0
Lessee, Operating Lease, Liability, Payments, Due Year Four		101.9
Lessee, Operating Lease, Liability, Payments, Due Year Five		89.7
Lessee, Operating Lease, Liability, Payments, Due after Year Five		330.4
Lessee, Operating Lease, Liability, Payments, Due		1,139.9
Lessee, Operating Lease, Imputed Interest	[1]	183.1
Operating Lease, Liability		$ 956.8	[2]	$ 1,189.6
Operating Leases, Future Minimum Payments, Due Thereafter					485.6
Operating Leases, Future Minimum Payments Due					1,519.7
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals					25.6
Operating Leases, Future Minimum Payments Due, Net of Future Sublease Rental Income					$ 1,494.1
Maximum
Maturities of lease liabilities [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		10 years

[1] (a) Calculated using the interest rate for each lease.

[2] (b) Includes the current portion of 275.1 million for operating leases.