Supplemental Balance Sheet Information (Property, Plant And Equipment, net) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 13,855.0	$ 13,197.1
Accumulated depreciation	(7,667.2)	(7,268.0)
Property, plant and equipment, net	6,187.8	5,929.1
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46.8	46.8
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	679.6	557.3
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,702.6	7,372.8
Store Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,533.9	2,400.2
Roasting Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	763.0	658.8
Furniture, Fixtures and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,786.5	1,659.3
Work in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 342.6	$ 501.9