Instruments With Potential Future Dilutive Effect Not Included In Calculation Of Diluted Earnings Per Share

No definition available.

Name:	cstm_InstrumentsWithPotentialFutureDilutiveEffectNotIncludedInCalculationOfDilutedEarningsPerShare
Namespace Prefix:	cstm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of sharebased payments vesting multiplier.

+ References

No definition available.

+ Details

Name:	cstm_PercentageOfSharebasedPaymentsVestingMultiplier
Namespace Prefix:	cstm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation vesting period.

+ References

No definition available.

+ Details

Name:	cstm_ShareBasedCompensationVestingPeriod
Namespace Prefix:	cstm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based Payment Arrangement Vesting Period

+ References

No definition available.

+ Details

Name:	cstm_ShareBasedPaymentArrangementVestingPeriod
Namespace Prefix:	cstm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based payment plans.

+ References

No definition available.

+ Details

Name:	cstm_ShareBasedPaymentPlansLineItems
Namespace Prefix:	cstm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Share price at granted date.

+ References

No definition available.

+ Details

Name:	cstm_SharePriceAtGrantedDate
Namespace Prefix:	cstm_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Sharebased Compensation stockholders return percentage.

+ References

No definition available.

+ Details

Name:	cstm_SharebasedCompensationStockholdersReturnPercentage
Namespace Prefix:	cstm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of expense from share-based payment transactions with employees. [Refer: Expense from share-based payment transactions]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2022-03-24
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2022-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 47
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2022-03-24

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2022-03-24
-Paragraph 45
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2022-en-r&anchor=para_45&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=cstm_PerformanceShareUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=cstm_RestrictedStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=cstm_CertainEmployeesAndChiefFinancialOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_KeyManagementPersonnelOfEntityOrParentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SHARE-BASED COMPENSATION - Narrative (Details) € / shares in Units, € in Millions	1 Months Ended						12 Months Ended
	Apr. 30, 2022 shares	Jul. 31, 2020 shares	May 31, 2020 shares	Apr. 30, 2019	May 31, 2018	Jul. 31, 2017	Dec. 31, 2022 EUR (€) shares € / shares	Dec. 31, 2021 EUR (€) shares € / shares	Dec. 31, 2020 EUR (€) shares	Dec. 31, 2019 shares
Share Based Payment Plans [line items]
Expense from share-based payment transactions with employees \| €							€ 18	€ 15	€ 15
Antidilutive securities (in shares)									6,402,289
PSUs
Share Based Payment Plans [line items]
Share based compensation, vesting period							3 years
Total shareholder return (TSR) percentage achieved				200.00%	182.90%	186.80%
Potential additional shares granted (in shares)	1,849,268	1,458,985	1,161,718
Share price at grant date (in EUR per share) \| € / shares							€ 17.11	€ 13.90
PSUs \| Bottom of range
Share Based Payment Plans [line items]
Percentage of vesting multiplier							0.00%
PSUs \| Top of range
Share Based Payment Plans [line items]
Percentage of vesting multiplier							200.00%
RSUs
Share Based Payment Plans [line items]
Potential additional shares granted (in shares)							556,360	534,499
RSUs \| Certain Employees And Chief Financial Officer
Share Based Payment Plans [line items]
Vesting period on the grant date							3 years
Share price at grant date (in EUR per share) \| € / shares							€ 17.11
RSUs \| Board Members
Share Based Payment Plans [line items]
Potential additional shares granted (in shares)							0	0	0	2