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Information by Geographic Area - Summary of Revenue Reported Based on Destination of Shipments (Detail) - EUR (€) € in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of geographical areas [line items]
Revenue	€ 5,237	€ 4,743	€ 5,153
France [member]
Disclosure of geographical areas [line items]
Revenue	557	493	564
Germany [member]
Disclosure of geographical areas [line items]
Revenue	1,217	1,042	1,112
United Kingdom [member]
Disclosure of geographical areas [line items]
Revenue	188	203	243
Switzerland [member]
Disclosure of geographical areas [line items]
Revenue	123	86	72
Other Europe [member]
Disclosure of geographical areas [line items]
Revenue	940	798	849
United States [member]
Disclosure of geographical areas [line items]
Revenue	1,691	1,511	1,677
Canada [member]
Disclosure of geographical areas [line items]
Revenue	78	68	91
Asia and Other Pacific [member]
Disclosure of geographical areas [line items]
Revenue	270	292	266
Other countries [member]
Disclosure of geographical areas [line items]
Revenue	€ 173	€ 250	€ 279

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants.

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