Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Apr. 01, 2018	Mar. 31, 2019	Apr. 01, 2018
Net earnings including noncontrolling interests	$ 658.8	$ 659.8	$ 1,419.0	$ 2,909.9
Other comprehensive loss, net of tax:
Other comprehensive income/(loss)	71.7	158.2	58.8	188.5
Comprehensive income including noncontrolling interests	730.5	818.0	1,477.8	3,098.4
Comprehensive income/(loss) attributable to noncontrolling interests	(4.4)	(0.3)	(4.6)	(0.4)
Comprehensive income attributable to Starbucks	734.9	818.3	1,482.4	3,098.8
Available-for-sale Securities [Member]
Other comprehensive loss, net of tax:
Unrealized holding gains/(losses) on available-for-sale securities, before tax	3.7	(3.3)	5.9	(6.0)
Unrealized holding gains/(losses) on available-for-sale securities, tax (expense)/benefit	(0.8)	0.7	(1.3)	1.7
Cash Flow Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	(12.4)	(43.1)	(21.5)	(45.4)
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	3.5	8.8	5.3	9.2
Net Investment Hedging [Member]
Other comprehensive loss, net of tax:
Unrealized gains/(losses) on hedging instruments, before tax	2.9	(43.9)	(19.0)	(44.2)
Unrealized gains/(losses) on hedging instruments, tax (expense)/benefit	(0.7)	11.1	4.9	11.1
Translation Adjustment [Member]
Other comprehensive loss, net of tax:
Translation adjustment and other, before tax	78.3	179.2	79.9	211.6
Translation adjustment and other, tax (expense)/benefit	1.4	(0.7)	1.4	2.2
Other comprehensive income/(loss)	79.7	202.6	81.3	230.7
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	(5.8)	55.3	2.3	55.5
Reclassification adjustment for net (gains)/losses realized in net earnings for available-for-sale securities, hedging instruments, and translation adjustment, tax expense/(benefit)	$ 1.6	$ (5.9)	$ 0.9	$ (7.2)