Financial Instruments - Fair Values on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ (55)	$ 27
Recurring
Schedule of Investments [Line Items]
Cash	8,900	8,900	$ 10,406
Total Estimated Fair Value
Cash, cash equivalents and marketable securities	43,703	43,703	41,676
Less: Restricted cash, cash equivalents, and marketable securities	(302)	(302)	(426)
Total cash, cash equivalents, and marketable securities	43,401	43,401	41,250
Cost or Amortized Cost
Cash, cash equivalents and marketable securities	43,419	43,419
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	60	60
Debt Securities, Available for Sale, Unrealized Loss	(6)	(6)
Recurring \| Level 1 securities
Total Estimated Fair Value
Equity Securities, FV-NI	225	225	170
Recurring \| Level 1 securities \| Money market funds
Schedule of Investments [Line Items]
Money market funds	9,869	9,869	12,515
Recurring \| Level 2 securities
Total Estimated Fair Value
Equity Securities, FV-NI	5	5	33
Recurring \| Level 2 securities \| Foreign government and agency securities
Total Estimated Fair Value
Debt Securities, Available for Sale, Fair Value	4,170	4,170	815
Cost or Amortized Cost
Debt Securities, Available for Sale, Cost	4,170	4,170
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	0	0
Debt Securities, Available for Sale, Unrealized Loss	0	0
Recurring \| Level 2 securities \| U.S. government and agency securities
Total Estimated Fair Value
Debt Securities, Available for Sale, Fair Value	6,884	6,884	11,667
Cost or Amortized Cost
Debt Securities, Available for Sale, Cost	6,875	6,875
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	13	13
Debt Securities, Available for Sale, Unrealized Loss	(4)	(4)
Recurring \| Level 2 securities \| Corporate debt securities
Total Estimated Fair Value
Debt Securities, Available for Sale, Fair Value	11,168	11,168	4,990
Cost or Amortized Cost
Debt Securities, Available for Sale, Cost	11,132	11,132
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	37	37
Debt Securities, Available for Sale, Unrealized Loss	(1)	(1)
Recurring \| Level 2 securities \| Asset-backed securities
Total Estimated Fair Value
Debt Securities, Available for Sale, Fair Value	2,187	2,187	892
Cost or Amortized Cost
Debt Securities, Available for Sale, Cost	2,180	2,180
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	8	8
Debt Securities, Available for Sale, Unrealized Loss	(1)	(1)
Recurring \| Level 2 securities \| Other fixed income securities
Total Estimated Fair Value
Debt Securities, Available for Sale, Fair Value	295	295	$ 188
Cost or Amortized Cost
Debt Securities, Available for Sale, Cost	293	293
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax
Debt Securities, Available for Sale, Unrealized Gain	2	2
Debt Securities, Available for Sale, Unrealized Loss	$ 0	$ 0

Cash, Cash Equivalents And Debt Available-For-Sale Securities, Amortized Cost Basis [Abstract]

No definition available.

Name:	amzn_CashCashEquivalentsAndDebtAvailableForSaleSecuritiesAmortizedCostBasisAbstract
Namespace Prefix:	amzn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash, Cash Equivalents, And Marketable Securities

+ References

No definition available.

+ Details

Name:	amzn_CashCashEquivalentsAndMarketableSecurities
Namespace Prefix:	amzn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash, Cash Equivalents, And Marketable Securities, Amortized Cost Basis

+ References

No definition available.

+ Details

Name:	amzn_CashCashEquivalentsAndMarketableSecuritiesAmortizedCostBasis
Namespace Prefix:	amzn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash, Cash Equivalents, And Marketable Securities, Excluding Restricted Cash And Investments

+ References

No definition available.

+ Details

Name:	amzn_CashCashEquivalentsAndMarketableSecuritiesExcludingRestrictedCashAndInvestments
Namespace Prefix:	amzn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

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

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118262064&loc=SL116631418-115840

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=118262064&loc=SL116631419-115840

+ Details

Name:	us-gaap_Cash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

+ Details

Name:	us-gaap_EquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

+ Details

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

- Definition

Cash and investments whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

+ References

No definition available.

+ Details

Name:	us-gaap_RestrictedCashAndInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: