Supplemental Balance Sheet Information (Property, Plant and Equipment, net) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Oct. 01, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 13,197.1	$ 11,584.0
Accumulated depreciation	(7,268.0)	(6,664.5)
Property, plant and equipment, net	5,929.1	4,919.5
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46.8	46.9
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	557.3	481.7
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,372.8	6,401.0
Store equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,400.2	2,110.7
Roasting equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	658.8	619.8
Furniture, fixtures and other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,659.3	1,514.1
Work in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 501.9	$ 409.8