Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 30, 2018	Dec. 31, 2017
Net earnings including noncontrolling interests	$ 760.4	$ 2,250.1
Other comprehensive loss, net of tax:
Other comprehensive income/(loss)	(12.9)	30.3
Comprehensive income including noncontrolling interests	747.5	2,280.4
Comprehensive income/(loss) attributable to noncontrolling interests	(0.2)	(0.1)
Comprehensive income attributable to Starbucks	747.7	2,280.5
Available-for-sale Securities [Member]
Other comprehensive loss, net of tax:
Unrealized holding gains/(losses) on available-for-sale securities, before tax	2.2	(2.7)
Unrealized holding gains/(losses) on available-for-sale securities, tax (expense)/benefit	(0.5)	1.0
Cash Flow Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	(9.1)	(2.3)
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	1.8	0.4
Net Investment Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	(21.9)	(0.3)
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	5.6	0.0
Translation Adjustment [Member]
Other comprehensive loss, net of tax:
Translation adjustment and other, before tax	1.6	32.4
Translation adjustment and other, tax (expense)/benefit	0.0	2.9
Other comprehensive income/(loss)	1.6	28.1
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	8.1	0.2
Reclassification adjustment for net (gains)/losses realized in net earnings for available-for-sale securities, hedging instruments, and translation adjustment, tax expense/(benefit)	$ (0.7)	$ (1.3)