Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Land	$ 192.7	$ 197.6
Buildings	7,425.6	6,917.8
Equipment	8,689.0	7,864.7
Construction in progress	1,783.8	1,797.5
Property and equipment, gross	18,091.1	16,777.6
Less accumulated depreciation	(9,264.6)	(8,525.0)
Property and equipment, net	8,826.5	8,252.6
Depreciation expense	763.1	716.2	$ 717.6
Rental expense	224.5	$ 221.0	$ 225.7
Property, Plant and Equipment [Line Items]
2018	130.8
2019	119.2
2020	105.7
2021	94.7
2022	77.1
After 2022	$ 245.7
Building | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years
Building | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	50 years
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years