Leases - Other (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Leases
Total undiscounted rent obligations	$ 5,511.6	$ 5,511.6
Sublease rent received	5.7	$ 11.1
Proceeds from sale-leaseback transactions	$ 7.3
Property leases | Minimum
Leases
Initial lease period (in years)	5 years	5 years
Property leases | Maximum
Leases
Initial lease period (in years)	20 years	20 years
Equipment leases | Maximum
Leases
Initial lease period (in years)	5 years	5 years