XML 97 R55.htm IDEA: XBRL DOCUMENT
v3.19.1

Inventories (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Text block [abstract] |
Disclosure of Inventories |
(in millions of Euros) |  | At December 31, 2018 |  |  | At December 31, 2017 |
Finished goods |  |  | 165 |  |  |  | 164 |
Work in progress |  |  | 347 |  |  |  | 332 |
Raw materials |  |  | 112 |  |  |  | 111 |
Stores and supplies |  |  | 67 |  |  |  | 64 |
Inventories write down |  |  | (31 | ) |  |  | (28 | )
Total inventories |  |  | 660 |  |  |  | 643 |

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_TextBlockAbstract
Namespace Prefix: | cstm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration