Supplemental Balance Sheet Information (Property, Plant And Equipment, net) (Details) - USD ($) $ in Millions	Mar. 28, 2021	Sep. 27, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,187.5	$ 14,155.3
Accumulated depreciation	(8,064.4)	(7,913.9)
Property, plant and equipment, net	6,123.1	6,241.4
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46.2	46.0
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	592.3	586.8
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8,246.4	8,262.6
Store Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,817.1	2,800.3
Roasting Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	807.0	796.6
Furniture, Fixtures and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,288.6	1,285.7
Work in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 389.9	$ 377.3