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Financial Risk Management - Summary of Effect of Foreign Currency Derivatives Impacts and Financing Transaction Exposures (Detail) - EUR (€) € in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of nature and extent of risks arising from financial instruments [line items]
Realized gain / (loss) on foreign currency derivatives-net	€ (15)	€ (46)	€ (37)
Unrealized gain / (loss) on foreign currency derivatives-net	17	40	(10)
Total	(79)	45	€ 50
Currency risk [member] | Finance costs [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Realized gain / (loss) on foreign currency derivatives-net	31	15
Unrealized gain / (loss) on foreign currency derivatives-net	(110)	30
Total	€ (79)	€ 45

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Realized gains (losses) on foreign currency derivatives - net.

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The gains (losses) resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 85
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_85&doctype=Standard
-URIDate 2017-03-09

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