Acquisition Effect of the change in Starbucks ownership interest in Starbucks Japan on Starbucks equity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net earnings attributable to Starbucks	$ 626.7	$ 512.6	$ 2,104.9	$ 1,480.3
Change from net earnings attributable to Starbucks and transfers (to)/from noncontrolling interest			2,106.6	1,480.3
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			$ 1.7	$ 0.0