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Investments Accounted for Under Equity Method - Summary of Investments Accounted for Under Equity Method (Detail) - EUR (€) € in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
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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] |  |  |  |  |
At January 1, |  |  | € 1 | € 16 | € 16
Joint venture's profit / (loss) | € (9) | € (7) | (12) | € (13) | (29)
Additions |  |  | 0 |  | 0
Reclassified to non-current other financial assets |  |  | 12 |  | 14
Effects of changes in foreign exchange rates |  |  | 0 |  | 0
Ending Balance | € 1 |  | € 1 |  | € 1

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- Definition Effect of foreign exchange rate. + References No definition available. + Details
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- Definition Investment accounted for using equity method reclassified to non-current other financial assets. + References No definition available. + Details
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- Definition Investment accounted for using equity methods additions. + References No definition available. + Details
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- Definition The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2017-01-01 -Paragraph 24 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_24_a&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2017-01-01 -Paragraph B16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_B16&doctype=Appendix&seq=2 -URIDate 2017-03-09 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 54 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_54_e&doctype=Standard -URIDate 2017-03-09 + Details
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- References No definition available. + Details
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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 + Details
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