XML 48 R41.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Inventories (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2018
Text block1 [abstract] |
Disclosure of Inventories |
(in millions of Euros) |  | At June 30, 2018 |  |  | At December 31, 2017 |
Finished goods |  |  | 182 |  |  |  | 164 |
Work in progress |  |  | 388 |  |  |  | 332 |
Raw materials |  |  | 137 |  |  |  | 111 |
Stores and supplies |  |  | 66 |  |  |  | 64 |
Adjustments(A) |  |  | (28 | ) |  |  | (28 | )
Total inventories |  |  | 745 |  |  |  | 643 |
(A) | Includes Net realizable value adjustments.

X
- Definition Disclosure of information about inventories explanatory. + References No definition available. + Details
Name: | cstm_DisclosureOfInformationAboutInventoriesExplanatory
Namespace Prefix: | cstm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Text Block [Abstract] + References No definition available. + Details
Name: | cstm_TextBlock1Abstract
Namespace Prefix: | cstm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration