Name:	ifrs-full_DisclosureOfBusinessCombinationsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of non-current derivative financial liabilities. [Refer: Derivative financial liabilities]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard
-URIDate 2025-03-27

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of non-current liabilities that the entity does not separately disclose in the same statement or note. [Refer: Non-current liabilities]

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Consideration Payable, Non-Current

No definition available.

Name:	mt_ConsiderationPayableNonCurrent
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Joint Venture Portion Included In Accrued Expenses and Liabilities

No definition available.

Name:	mt_JointVenturePortionIncludedInAccruedExpensesAndLiabilities
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Loss Contingency, Settlement Payment

No definition available.

Name:	mt_LossContingencySettlementPayment
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Non-cash Acquisition of Joint Venture Equity

No definition available.

Name:	mt_NonCashAcquisitionOfJointVentureEquity
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Other Non-Current Liabilities, Income Taxes Payable

No definition available.

Name:	mt_OtherNonCurrentLiabilitiesIncomeTaxesPayable
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Other Non-Current Liabilities, Other

No definition available.

Name:	mt_OtherNonCurrentLiabilitiesOther
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Other Non-Current Liabilities, Unfavorable Contracts

No definition available.

Name:	mt_OtherNonCurrentLiabilitiesUnfavorableContracts
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Payable For Put Option Liability

No definition available.

Name:	mt_PayableForPutOptionLiability
Namespace Prefix:	mt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_BusinessCombinationsAxis=mt_SonasidMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_BusinessCombinationsAxis=mt_ArcelorMittalSulFluminenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_FinancialGuaranteeContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: