XML 101 R93.htm IDEA: XBRL DOCUMENT
v3.20.2

FINANCIAL RISK MANAGEMENT - Additional Information (Details) € in Millions, SFr in Millions, $ in Millions | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Dec. 31, 2019 EUR (€) | Jun. 30, 2020 EUR (€) | Jun. 30, 2020 USD ($) | Dec. 31, 2019 USD ($) | Jun. 30, 2019 EUR (€) | Jun. 30, 2019 CHF (SFr) | Dec. 31, 2018 EUR (€)
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Revolving credit facilities outstanding | € 281 | € 506 |  |  |  |  |
Liquidity value | 516 | 949 |  |  |  |  |
Cash and cash equivalents | 184 | 378 |  |  | € 213 |  | € 164
Undrawn facilities | 332 | 571 |  |  |  |  |
Secured Pan-U.S. ABL (due 2022) |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Borrowing base | $ |  |  | $ 322 | $ 375 |  |  |
Secured U.S. DDTL (due 2022) |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Borrowing base | $ |  |  | 166 |  |  |  |
French inventory facility |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Borrowing base | 82 | € 78 |  |  |  |  |
Forward contract |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Total nominal amount forward contracts | SFr |  |  |  |  |  | SFr 174 |
Unrealized loss of the net investment hedge | € 3 |  |  |  |  |  |
Derivative classified as cash flow hedge |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Nominal amount hedging instrument | $ |  |  | 109 | $ 233 |  |  |
Derivative classified as cash flow hedge | Foreign exchange forward contracts |  |  |  |  |  |  |
Disclosure of liquidity risk [line items] |  |  |  |  |  |  |
Nominal amount hedging instrument | $ |  |  | $ 255 |  |  |  |

X
- Definition Available borrowings under credit facility. + References No definition available. + Details
Name: | cstm_BorrowingFacility
Namespace Prefix: | cstm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disclosure of liquidity risk. + References No definition available. + Details
Name: | cstm_DisclosureOfLiquidityRiskLineItems
Namespace Prefix: | cstm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total nominal amount of hedging instrument. + References No definition available. + Details
Name: | cstm_FullNominalAmountOfHedgingInstrument
Namespace Prefix: | cstm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Nominal amount of hedging instruments. + References No definition available. + Details
Name: | cstm_NominalAmountOfHedgingInstruments
Namespace Prefix: | cstm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Revolving credit facility outstanding. + References No definition available. + Details
Name: | cstm_RevolvingCreditFacilityOutstanding
Namespace Prefix: | cstm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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 2019-01-01 -Paragraph 45 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2019-en-r&anchor=para_45&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph B13 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_B13_a&doctype=Appendix&subtype=B -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 54 -Subparagraph i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_i&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_CashAndCashEquivalents
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 2019-01-01 -Paragraph B11E -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_B11E&doctype=Appendix&subtype=B -URIDate 2019-03-27 + Details
Name: | ifrs-full_FinancialAssetsHeldForManagingLiquidityRisk
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The gains (losses) recognised in other comprehensive income on hedges of net investments in foreign operations, before tax. [Refer: Other comprehensive income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 39 -IssueDate 2019-01-01 -Paragraph 102 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=39&code=ifrs-tx-2019-en-r&anchor=para_102_a&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 91 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_91_b&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 9 -IssueDate 2019-01-01 -Paragraph 6.5.13 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2019-en-r&anchor=para_6.5.13_a&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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 -IssueDate 2019-01-01 -Paragraph 50 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2019-en-r&anchor=para_50_a&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_UndrawnBorrowingFacilities
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=cstm_PanUsAblFacilityDueTwoThousandTwentyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=cstm_U.S.DDTLMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=cstm_FrenchInventoryFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_ForwardContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_HedgingInstrumentsAxis=cstm_DerivativeClassifiedAsCashFlowHedgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=cstm_ForeignExchangeForwardContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |