Analysis of Net Debt - Additional Information (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Apr. 30, 2019
Disclosure of Financial Assets and Liabilities [line items]
Cash and cash equivalents	€ 3,755	€ 2,346
Undrawn committed loan facilities	€ 3,610	€ 3,583	€ 3,500
Euro [member]
Disclosure of Financial Assets and Liabilities [line items]
Percentage of total cash and cash equivalents	52.00%	46.00%
US Dollar [member]
Disclosure of Financial Assets and Liabilities [line items]
Percentage of total cash and cash equivalents	23.00%	27.00%

The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant