Other Intangible Assets and Goodwill (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jul. 02, 2017	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Goodwill [Line Items]
Goodwill, Impairment Loss		$ 87.2	$ 0.0	$ 0.0
Goodwill		1,539.2	1,719.6	1,575.4
Other intangible assets		441.4	516.3
Amortization expense for finite-lived intangible assets		57.5	$ 57.3	$ 50.0
Teavana [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 69.3
Goodwill		398.3
Other intangible assets		117.2
Starbucks Coffee Switzerland [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 17.9
Goodwill		$ 37.0