Available borrowings under credit facility.

No definition available.

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- Definition

Disclosure of liquidity risk.

+ References

No definition available.

+ Details

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- Definition

Total nominal amount of hedging instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	cstm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Impact of increase or decrease in interest rate in income loss before income tax.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Impact of increase or decrease in market price in gain or loss from derivatives.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Margin Requirement Paid As Collateral To Counterparty

+ References

No definition available.

+ Details

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Namespace Prefix:	cstm_
Data Type:	xbrli:monetaryItemType
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- Definition

Net position hedges related to loans and deposits.

+ References

No definition available.

+ Details

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Namespace Prefix:	cstm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of trade account receivables insured.

+ References

No definition available.

+ Details

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Namespace Prefix:	cstm_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Revolving credit facility outstanding.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2023-01-01
-Paragraph 45
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2023-en-r&anchor=para_45&doctype=Standard
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2023-03-23

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The amount of financial assets held for managing liquidity risk (for example, financial assets that are readily saleable or expected to generate cash inflows to meet cash outflows on financial liabilities). [Refer: Liquidity risk [member]; Financial assets; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph B11E
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_B11E&doctype=Appendix&subtype=B
-URIDate 2023-03-23

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The amount of undrawn borrowing facilities that may be available for future operating activities and to settle capital commitments. [Refer: Capital commitments]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
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-Paragraph 50
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-URIDate 2023-03-23

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ifrs-full_HedgingInstrumentsAxis=cstm_DerivativeClassifiedAsCashFlowHedgeMember
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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=cstm_SecuredPanUSABLMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Name:	ifrs-full_TypesOfRisksAxis=ifrs-full_CurrencyRiskMember
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FINANCIAL RISK MANAGEMENT - Narrative (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 EUR (€)	Dec. 31, 2020 EUR (€)
Disclosure of liquidity risk [line items]
Percentage of trade account receivables insured	80.00%			80.00%
Revolving credit facilities outstanding availability	€ 524
Liquidity value	737		€ 709
Cash and cash equivalents	202		166			€ 147	€ 439
Undrawn facilities	535		543
Derivative classified as cash flow hedge
Disclosure of liquidity risk [line items]
Nominal amount hedging instrument \| $				$ 209	$ 248
Forward purchase contracts versus EURO \| Foreign exchange forward contracts
Disclosure of liquidity risk [line items]
Net position hedges related to loans and deposits \| $		$ 82
U.S. Revolving Facility
Disclosure of liquidity risk [line items]
Borrowing base \| $				$ 439
French Inventory Based Facility
Disclosure of liquidity risk [line items]
Borrowing base	100
Currency risk
Disclosure of liquidity risk [line items]
Margin requirement paid as collateral to counterparties			0
10% increase or decrease in the market price \| Aluminium
Disclosure of liquidity risk [line items]
Impact of increase or decrease in market price in gain or loss from derivatives	38
Top of range \| 50 basis point increase or decrease in the LIBOR or EURIBOR interest rates
Disclosure of liquidity risk [line items]
Impact of increase or decrease in interest rate in income before income tax	€ 3		€ 3