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Investments Accounted for Under Equity Method - Additional Information (Detail) - EUR (€) € in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Share of profit (loss) of associates and joint ventures accounted for using equity method [abstract]
Cumulative share of losses of joint-ventures in excess of initial investment			€ 28
Share of losses of joint-ventures in excess of initial investment	€ 9	€ 7	€ 12	€ 13	€ 29

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- Definition

Cumulative share of profit (loss) of joint ventures accounted for using equity method.

+ References

No definition available.

+ Details

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- References

No definition available.

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- Definition

The entity's share of the profit (loss) of joint ventures accounted for using the equity method. [Refer: Investments accounted for using equity method; Joint ventures [member]; Profit (loss)]

+ 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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