Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Net earnings including noncontrolling interests	$ 2,250.1	$ 751.5
Other comprehensive loss, net of tax:
Other comprehensive income/(loss)	30.3	(133.9)
Comprehensive income including noncontrolling interests	2,280.4	617.6
Comprehensive income/(loss) attributable to noncontrolling interests	(0.1)	(0.3)
Comprehensive income attributable to Starbucks	2,280.5	617.9
Available-for-sale Securities [Member]
Other comprehensive loss, net of tax:
Unrealized holding gains/(losses) on available-for-sale securities, before tax	(2.8)	(13.4)
Unrealized holding gains/(losses) on available-for-sale securities, tax (expense)/benefit	1.0	4.1
Cash Flow Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	(3.7)	113.5
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	0.8	(26.5)
Net Investment Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	(0.3)	41.1
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	0.1	(15.2)
Translation Adjustment [Member]
Other comprehensive loss, net of tax:
Translation adjustment and other, before tax	18.0	(171.8)
Translation adjustment and other, tax (expense)/benefit	2.9	0.0
Other comprehensive income/(loss)	28.1	(171.8)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Other comprehensive loss, net of tax:
Reclassification adjustment for net (gains)/losses realized in net earnings for available-for-sale securities, hedging instruments, and translation adjustment, before tax	15.1	(81.7)
Reclassification adjustment for net (gains)/losses realized in net earnings for available-for-sale securities, hedging instruments, and translation adjustment, tax expense/(benefit)	$ (0.8)	$ 16.0