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
	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
Earnings Per Share [Abstract]
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
Weighted average common shares and common stock units outstanding (for basic calculation)																	1,495.9		1,506.3		1,498.5
Dilutive effect of outstanding common stock options and RSUs																	17.5		20.0		26.0
Weighted average common and common equivalent shares outstanding (for diluted calculation)																	1,513.4		1,526.3		1,524.5
EPS - basic																	$ 1.84		$ 1.37		$ 0.01
EPS - diluted	$ 0.43	[1]	$ 0.41	[1]	$ 0.33	[1]	$ 0.65	[1]	$ 0.39	[1]	$ 0.34	[1]	$ 0.28	[1]	$ 0.35	[1]	$ 1.82	[1]	$ 1.35	[1]	$ 0.01

[1] As discussed in Note 1, Summary of Significant Accounting Policies, on April 9, 2015, we effected a two-for-one stock split of our $0.001 par value common stock for shareholders of record as of March 30, 2015. All per-share data presented in this note has been retroactively adjusted to reflect this stock split.