v3.25.4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) | 12 Months Ended
--- | ---
Dec. 31, 2025 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($)
Significant Accounting Policies [Line Items] |  |  |
Compensation costs from retirement savings plan | $ 264,000,000 | $ 240,000,000 | $ 215,000,000
Advertising costs | 999,000,000 | 993,000,000 | 794,000,000
Allowance for credit losses | 212,000,000 | 199,000,000 |
Goodwill impairment charge | 0 | 0 | $ 0
Self-insurance reserve, employee benefits related | 72,000,000 | 74,000,000 |
Self-insurance reserve, current | 178,000,000 | 198,000,000 |
Self-insurance reserve, noncurrent | $ 496,000,000 | 422,000,000 |
Measurement Input, Discount Rate | Valuation Technique, Discounted Cash Flow |  |  |
Significant Accounting Policies [Line Items] |  |  |
Self insurance review, measurement input | 0.0350 |  |
Costs Incurred to Fulfill Contracts |  |  |
Significant Accounting Policies [Line Items] |  |  |
Capitalized costs | $ 439,000,000 | 419,000,000 |
Deferred revenue |  |  |
Significant Accounting Policies [Line Items] |  |  |
Increase (decrease) in deferred revenue | 110,000,000 |  |
Current and noncurrent deferred revenue | 1,409,000,000 | 1,299,000,000 |
Deferred revenue recognized | 242,000,000 |  |
Liability for guest loyalty program |  |  |
Significant Accounting Policies [Line Items] |  |  |
Increase (decrease) in deferred revenue | 473,000,000 |  |
Current and noncurrent deferred revenue | 7,992,000,000 | $ 7,519,000,000 |
Deferred revenue recognized | 3,160,000,000 |  |
Change in customer contract liability from change in estimates | $ 102,000,000 |  |

X
- Definition Self Insurance Reserve, Employee Benefit Related + References No definition available. + Details
Name: | mar_SelfInsuranceReserveEmployeeBenefitRelated
Namespace Prefix: | mar_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Self Insurance Reserve, Measurement Input + References No definition available. + Details
Name: | mar_SelfInsuranceReserveMeasurementInput
Namespace Prefix: | mar_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | mar_SignificantAccountingPoliciesLineItems
Namespace Prefix: | mar_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit loss of accounts and financing receivables. Includes, but is not limited to, notes and loan receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-4 + Details
Name: | us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 720 -SubTopic 35 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483385/720-35-55-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 720 -SubTopic 35 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483406/720-35-50-1 + Details
Name: | us-gaap_AdvertisingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 340 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479483/340-40-50-3 + Details
Name: | us-gaap_CapitalizedContractCostNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-11 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479837/606-10-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-8 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479837/606-10-45-2 + Details
Name: | us-gaap_ContractWithCustomerLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-10 + Details
Name: | us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-8 + Details
Name: | us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480794/715-70-50-1 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of impairment loss from asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 350 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 24 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482548/350-20-55-24 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 350 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482573/350-20-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 350 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482573/350-20-50-6 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 350 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482573/350-20-50-1 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 350 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482598/350-20-45-2 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 805 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479581/805-30-50-4 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 912 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478345/912-310-45-11 + Details
Name: | us-gaap_IncreaseDecreaseInContractWithCustomerLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying amount of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property that are expected to be paid within one year (or the normal operating cycle, if longer). + References No definition available. + Details
Name: | us-gaap_SelfInsuranceReserveCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Carrying amount of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property that are expected to be paid after one year (or the normal operating cycle, if longer). + References No definition available. + Details
Name: | us-gaap_SelfInsuranceReserveNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueDiscountedCashFlowMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CapitalizedContractCostAxis=mar_CostsIncurredtoFulfillContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mar_ContractServicesExcludingLoyaltyProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=mar_LoyaltyProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |