Selected Quarterly Financial Information (Schedule of Selected Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 29, 2019	Sep. 30, 2018	Oct. 01, 2017
Selected Quarterly Financial Information [Abstract]
Revenues	$ 6,747.0	$ 6,823.0	$ 6,305.9	$ 6,632.7	$ 6,303.6	$ 6,310.3	$ 6,031.8	$ 6,073.7	$ 26,508.6	$ 24,719.5	$ 22,386.8
Operating income	1,083.3	1,121.3	857.7	1,015.7	956.6	1,038.2	772.5	1,116.1	4,077.9	3,883.3	4,134.7
Net earnings attributable to Starbucks	$ 802.9	$ 1,372.8	$ 663.2	$ 760.6	$ 755.8	$ 852.5	$ 660.1	$ 2,250.2	$ 3,599.2	$ 4,518.3	$ 2,884.7
Earnings Per Share, Diluted	$ 0.67	$ 1.12	$ 0.53	$ 0.61	$ 0.56	$ 0.61	$ 0.47	$ 1.57	$ 2.92	$ 3.24	$ 1.97