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REVENUE - Disaggregation of Revenue by Destination of Shipment (Details) - EUR (€) € in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | € 4,883 | € 5,907 | € 5,686
Germany |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 1,014 | 1,260 | 1,339
France |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 362 | 563 | 554
United Kingdom |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 192 | 194 | 175
Switzerland |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 52 | 68 | 77
Other Europe |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 923 | 1,078 | 1,038
Total Europe |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 2,543 | 3,163 | 3,183
United States |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 1,941 | 2,175 | 1,897
Asia and Other Pacific |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | 211 | 277 | 300
All Other |  |  |
Disclosure of geographical areas [line items] |  |  |
Total Revenue by product line | € 188 | € 292 | € 306

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- Definition The amount of revenue from contracts with customers. A customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 113 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_113_a&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 114 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_114&doctype=Standard -URIDate 2020-01-01 + Details
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