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Expenses by Nature | 12 Months Ended
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Dec. 31, 2017
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Expenses by Nature | NOTE 5—EXPENSES BY NATURE
(in millions of Euros) |  | Notes |  | Year ended December 31, 2017 |  |  | Year ended December 31, 2016 |  |  | Year ended December 31, 2015 |
Raw materials and consumables used |  |  |  |  | (3,197 | ) |  |  | (2,792 | ) |  |  | (3,176 | )
Employee benefit expenses |  | 6 |  |  | (924 | ) |  |  | (897 | ) |  |  | (887 | )
Energy costs |  |  |  |  | (138 | ) |  |  | (140 | ) |  |  | (168 | )
Sub-contractors |  |  |  |  | (99 | ) |  |  | (108 | ) |  |  | (86 | )
Freight out costs |  |  |  |  | (124 | ) |  |  | (128 | ) |  |  | (130 | )
Professional fees |  |  |  |  | (77 | ) |  |  | (85 | ) |  |  | (75 | )
Operating lease expenses |  |  |  |  | (27 | ) |  |  | (27 | ) |  |  | (29 | )
Depreciation and amortization |  | 15,16 |  |  | (171 | ) |  |  | (155 | ) |  |  | (140 | )
Impairment |  | 15 |  |  | — |  |  |  | — |  |  |  | (457 | )
Other operating expenses |  |  |  |  | (229 | ) |  |  | (186 | ) |  |  | (300 | )
Other gains / (losses)—net |  | 7 |  |  | 70 |  |  |  | 21 |  |  |  | (131 | )
Total Operating expenses |  |  |  |  | (4,916 | ) |  |  | (4,497 | ) |  |  | (5,579 | )

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- Definition The disclosure of expenses by nature. [Refer: Expenses, by nature] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 10 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_10_e&doctype=Standard -URIDate 2017-03-09 + Details
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