XML 127 R85.htm IDEA: XBRL DOCUMENT v3.19.1

Operating Segment Information - Summary of Segment Capital Expenditures (Detail) - EUR (€) € in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of operating segments [line items]
Segment capital expenditures	€ (277)	€ (276)	€ (355)
P&ARP [member]
Disclosure of operating segments [line items]
Segment capital expenditures	(97)	(115)	(166)
A&T [member]
Disclosure of operating segments [line items]
Segment capital expenditures	(70)	(73)	(96)
AS&I [member]
Disclosure of operating segments [line items]
Segment capital expenditures	(105)	(83)	(84)
Holdings & Corporate [member]
Disclosure of operating segments [line items]
Segment capital expenditures	€ (5)	€ (5)	€ (9)

X

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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

X

- Definition

The cash outflow for the purchases of property, plant and equipment, classified as investing activities. [Refer: Property, plant and equipment]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2018-01-01
-Paragraph 16
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_16_a&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	ifrs-full_SegmentsAxis=cstm_PackagingAndAutomotiveRolledProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=cstm_AerospaceAndTransportationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=cstm_AutomotiveStructuresAndIndustryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SegmentsAxis=cstm_HoldingsAndCorporateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: