Selected Quarterly Financial Information (Schedule of Selected Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Jan. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Oct. 02, 2016
Selected Quarterly Financial Information [Abstract]
Revenues	$ 6,303.6	$ 6,310.3	$ 6,031.8	$ 6,073.7	$ 5,698.3	$ 5,661.5	$ 5,294.0	$ 5,732.9	$ 24,719.5	$ 22,386.8	$ 21,315.9
Operating income	956.6	1,038.2	772.5	1,116.1	1,022.5	1,044.2	935.4	1,132.6	3,883.3	4,134.7	4,171.9
Net earnings attributable to Starbucks	$ 755.8	$ 852.5	$ 660.1	$ 2,250.2	$ 788.5	$ 691.6	$ 652.8	$ 751.8	$ 4,518.3	$ 2,884.7	$ 2,817.7
Earnings Per Share, Diluted	$ 0.56	$ 0.61	$ 0.47	$ 1.57	$ 0.54	$ 0.47	$ 0.45	$ 0.51	$ 3.24	$ 1.97	$ 1.90