Acquisition of land use rights

No definition available.

Name:	bkng_Acquisitionoflanduserights
Namespace Prefix:	bkng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Estimated possible fine

+ References

No definition available.

+ Details

Name:	bkng_EstimatedPossibleFine
Namespace Prefix:	bkng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Income Taxes, Percent Of Tax And Interest Expected To Be Paid Pending Proceedings

+ References

No definition available.

+ Details

Name:	bkng_IncomeTaxesPercentOfTaxAndInterestExpectedToBePaidPendingProceedings
Namespace Prefix:	bkng_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the tax assessment issued by the tax authority including interest and penalties.

+ References

No definition available.

+ Details

Name:	bkng_LossContingencyTaxInterestandPenaltiesAssessed
Namespace Prefix:	bkng_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the tax assessment amount recommended by the tax authority excluding interest and penalties.

+ References

No definition available.

+ Details

Name:	bkng_LossContingencyTaxRecommendedAssessment
Namespace Prefix:	bkng_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Payment required to appeal a litigation matter

+ References

No definition available.

+ Details

Name:	bkng_Paymentrequiredtoappealalitigationmatter
Namespace Prefix:	bkng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

+ References

No definition available.

+ Details

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

- Definition

Term of lessee's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918701-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

+ Details

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

- Definition

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 05
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99385795&loc=d3e12631-108344

+ Details

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

- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
-URI http://asc.fasb.org/extlink&oid=123427490&loc=SL37586934-109318

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=SL6600010-109319

+ Details

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

- Definition

Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=bkng_Booking.comMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=bkng_HeadquartersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=bkng_VendorsUsedToFitOutAndFurnishOfficeSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bkng_LeaseArrangementAxis=bkng_GroundLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bkng_Rentalcars.comMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=bkng_ManchesterEnglandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bkng_LeaseArrangementAxis=bkng_OperatingLeaseObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_PotentialFineUnderContractualParityAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_FrenchTaxAuditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=bkng_TaxYears2006Through2012Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_AssessmenttransfertaxesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=bkng_TaxYears2011Through2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_ItalianTaxAuditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=bkng_TaxYears2013And2014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=bkng_TaxYears2013Through2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_TurkishTaxAuditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_TravelTransactionRelatedTaxesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=bkng_PensionrelatedlitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_UnfavorableRegulatoryActionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

COMMITMENTS AND CONTINGENCIES (Details) ₺ in Millions, € in Millions, £ in Millions, $ in Millions	1 Months Ended														6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2021 EUR (€)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)	Jan. 31, 2019 USD ($)	Jan. 31, 2019 EUR (€)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 EUR (€)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 EUR (€)	Jun. 30, 2021 TRY (₺)	Jun. 30, 2021 EUR (€)	Jun. 30, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Sep. 30, 2016 EUR (€)
Commitments and Contingencies
Unrecognized tax benefits	$ 102														$ 102					$ 84
Booking.com \| Headquarters
Commitments and Contingencies
Contractual obligation	39										$ 321				39			€ 33				€ 270
Acquisition of land use rights											$ 48	€ 43
Booking.com \| Headquarters \| Headquarters Vendors
Commitments and Contingencies
Contractual obligation	38														38			32
Booking.com \| Headquarters \| Ground Lease
Commitments and Contingencies
Remaining lease payments	$ 82														$ 82			€ 69
Rentalcars.com \| Headquarters \| Manchester, England
Commitments and Contingencies
Lease term of operating leases which have not commenced at period end	13 years														13 years			13 years	13 years
Rentalcars.com \| Headquarters \| Operating Lease Obligations \| Manchester, England
Commitments and Contingencies
Contractual obligation	$ 89														$ 89				£ 65
Potential Fine under Contractual Parity Agreement
Commitments and Contingencies
Accruals for loss contingencies	22														22					23
French Tax Audit
Commitments and Contingencies
Unrecognized tax benefits																				59	€ 50
Estimated reasonably possible loss in excess of amount accrued	$ 24														24			€ 20
French Tax Audit \| Tax Year 2013
Commitments and Contingencies
Assessed taxes including interest and penalties					$ 83	€ 70
French Tax Audit \| Tax Years 2006 Through 2012
Commitments and Contingencies
Assessed taxes including interest and penalties													$ 403	€ 356
Payment required to appeal a litigation matter or avoid collection enforcement							$ 403	€ 356
French Tax Assessment, transfer taxes \| Tax Years 2011 Through 2015
Commitments and Contingencies
Assessed taxes including interest and penalties					47	39
Italian Tax Audit
Commitments and Contingencies
Net unrecognized tax benefit recognized															$ 16	€ 13
Income taxes, percent of tax and interest expected to be paid related to pending proceedings	33.00%														33.00%			33.00%	33.00%
Italian Tax Audit \| Other assets, net
Commitments and Contingencies
Unrecognized tax benefits	$ 6														$ 6			€ 5		6	5
Italian Tax Audit \| Tax Year 2013
Commitments and Contingencies
Assessed taxes including interest and penalties									$ 56	€ 48
Payment required to appeal a litigation matter or avoid collection enforcement					11	10
Italian Tax Audit \| Tax Year 2014
Commitments and Contingencies
Assessed taxes including interest and penalties					$ 69	€ 58
Italian Tax Audit \| Tax Year 2015
Commitments and Contingencies
Assessed taxes including interest and penalties			$ 37	€ 31
Italian Tax Audit \| Tax Years 2013 And 2014
Commitments and Contingencies
Unrecognized tax benefits																				5	€ 4
Italian Tax Audit \| Tax Years 2013 through 2019
Commitments and Contingencies
Loss Contingency, Tax, Recommended Assessment	182	€ 154
Turkish Tax Audit
Commitments and Contingencies
Assessed taxes including interest and penalties															91		₺ 789
Travel Transaction Related Taxes
Commitments and Contingencies
Accruals for loss contingencies	59														59					$ 59
Estimated reasonably possible loss in excess of amount accrued	20														20
Pension-related litigation
Commitments and Contingencies
Estimated reasonably possible loss in excess of amount accrued	316														316
Unfavorable Regulatory Action \| Maximum
Commitments and Contingencies
Estimated possible fine per incident	$ 24														$ 24			€ 20