Derivative Financial Instruments (Derivative Gains and Losses Included in AOCI and Expected to be Reclassified into Earnings in 12 Months, Net of Tax) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Sep. 30, 2018
Cash Flow Hedging [Member] \| Interest Rate Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ (0.2)	$ 24.7
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 4.3
Outstanding Contract Remaining Maturity (Months)	119 months
Cash Flow Hedging [Member] \| Cross-Currency Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ (6.3)	(12.6)
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 0.0
Outstanding Contract Remaining Maturity (Months)	68 months
Cash Flow Hedging [Member] \| Foreign Currency Contract - Other [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ 10.8	5.8
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 6.2
Outstanding Contract Remaining Maturity (Months)	35 months
Cash Flow Hedging [Member] \| Coffee Contracts [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ 0.0	(0.2)
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 0.0
Outstanding Contract Remaining Maturity (Months)	0 months
Net Investment Hedging [Member] \| Foreign Currency Contract - Other [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ 16.0	16.0
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 0.0
Outstanding Contract Remaining Maturity (Months)	0 months
Net Investment Hedging [Member] \| ForeignExchangeYenDebt [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Gains/(Losses) Included in AOCI	$ (10.5)	$ 3.6
Net Gains/(Losses) Expected to be Reclassified from AOCI into Earnings within 12 Months	$ 0.0
Outstanding Contract Remaining Maturity (Months)	60 months

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e681-108580

+ Details

Name:	us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

+ Details

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeRemainingMaturity1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after tax, of cumulative translation adjustment attributable to gain (loss) on foreign currency derivatives that are designated as, and are effective as, economic hedges of a net investment in a foreign entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section 45
-Paragraph 20
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109240241&loc=d3e32211-110900

+ Details

Name:	us-gaap_TranslationAdjustmentForNetInvestmentHedgeNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CrossCurrencyInterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=sbux_CoffeeContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=sbux_ForeignExchangeYenDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: