Acquisitions and Divestitures (Effect of the change in Starbucks ownership interest in Starbucks Japan on Starbucks equity) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 29, 2013	Sep. 27, 2015	Sep. 28, 2014	Sep. 29, 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net earnings attributable to Starbucks	$ 652.5	$ 626.7	$ 494.9	$ 983.1	$ 587.9	$ 512.6	$ 427.0	$ 540.7	$ 2,757.4	$ 2,068.1	$ 8.3
Increase/(decrease) in additional paid-in capital for purchase of interest in subsidiary									1.7
Change from net earnings attributable to Starbucks and transfers (to)/from noncontrolling interest									$ 2,759.1	2,068.1
Additional Paid-in Capital [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Increase/(decrease) in additional paid-in capital for purchase of interest in subsidiary										$ 0.0