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								12 Months Ended
	Oct. 02, 2016	Jun. 26, 2016	Mar. 27, 2016	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Oct. 02, 2016	Sep. 27, 2015	Sep. 28, 2014
Earnings Per Share [Abstract]
Net earnings attributable to Starbucks	$ 801.0	$ 754.1	$ 575.1	$ 687.6	$ 652.5	$ 626.7	$ 494.9	$ 983.1	$ 2,817.7	$ 2,757.4	$ 2,068.1
Weighted average common shares and common stock units outstanding (for basic calculation)									1,471.6	1,495.9	1,506.3
Dilutive effect of outstanding common stock options and RSUs									15.1	17.5	20.0
Weighted average common and common equivalent shares outstanding (for diluted calculation)									1,486.7	1,513.4	1,526.3
EPS - basic									$ 1.91	$ 1.84	$ 1.37
EPS - diluted	$ 0.54	$ 0.51	$ 0.39	$ 0.46	$ 0.43	$ 0.41	$ 0.33	$ 0.65	$ 1.90	$ 1.82	$ 1.35