Earnings Per Share (Calculation of Net Earnings Per Common Share (EPS) - Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Earnings Per Share [Abstract]
Document Period End Date			Jun. 30, 2019
Net earnings attributable to Starbucks	$ 1,372.8	$ 852.5	$ 2,796.4	$ 3,762.8
Weighted average common shares outstanding (for basic calculation)	1,211.0	1,377.1	1,230.8	1,397.7
Dilutive effect of outstanding common stock options and RSUs	12.0	11.4	11.6	12.2
Weighted average common and common equivalent shares outstanding (for diluted calculation)	1,223.0	1,388.5	1,242.4	1,409.9
Earnings per share - basic	$ 1.13	$ 0.62	$ 2.27	$ 2.69
Earnings per share - diluted	$ 1.12	$ 0.61	$ 2.25	$ 2.67