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Financial Risk Management - Summary of Undiscounted Contractual Values by Relevant Maturity Groupings (Detail) - EUR (€) € in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Less than 1 year [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | € 65 | € 54
Financial liabilities | 1,110 | 1,084
Less than 1 year [member] | Borrowings [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 67 | 54
Less than 1 year [member] | Interests [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 103 | 170
Less than 1 year [member] | Net debt derivative liabilities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 3 |
Less than 1 year [member] | Net cash flows from derivatives liabilities related to currencies and commodities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 17 | 35
Less than 1 year [member] | Trade payables and other (excluding deferred revenue) [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 920 | 825
Less than 1 year [member] | Net debt derivative assets [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | 6 | 32
Less than 1 year [member] | Net cash flows from derivative assets related to currencies and commodities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | 59 | 22
Between 1 and 5 years [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | 18 | 85
Financial liabilities | 780 | 1,901
Between 1 and 5 years [member] | Borrowings [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 318 | 1,329
Between 1 and 5 years [member] | Interests [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 421 | 490
Between 1 and 5 years [member] | Net debt derivative liabilities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 10 |
Between 1 and 5 years [member] | Net cash flows from derivatives liabilities related to currencies and commodities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 11 | 63
Between 1 and 5 years [member] | Trade payables and other (excluding deferred revenue) [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 20 | 19
Between 1 and 5 years [member] | Net debt derivative assets [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | 3 | 82
Between 1 and 5 years [member] | Net cash flows from derivative assets related to currencies and commodities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial assets | 15 | 3
More than 5 years [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 1,956 | 1,127
More than 5 years [member] | Borrowings [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | 1,692 | 999
More than 5 years [member] | Interests [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities | € 264 | 125
More than 5 years [member] | Net cash flows from derivatives liabilities related to currencies and commodities [member] |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities |  | € 3

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