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PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Net Defined Benefit Obligations by Country (Details) € in Millions, $ in Millions | Dec. 31, 2020 EUR (€) | Dec. 31, 2019 EUR (€) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 EUR (€)
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Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | € 1,122 | € 1,115 |  |
Plan assets | (458) | (445) |  |
Net defined benefit liability | 664 | 670 | $ 670 | € 610
France |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | 168 | 161 |  |
Plan assets | (5) | (3) |  |
Net defined benefit liability | 163 | 158 |  |
Germany |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | 143 | 144 |  |
Plan assets | (1) | (1) |  |
Net defined benefit liability | 142 | 143 |  |
Switzerland |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | 310 | 299 |  |
Plan assets | (223) | (214) |  |
Net defined benefit liability | 87 | 85 |  |
United States |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | 500 | 510 |  |
Plan assets | (229) | (227) |  |
Net defined benefit liability | 271 | 283 |  |
Other |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Defined benefit obligations | 1 | 1 |  |
Plan assets | 0 | 0 |  |
Net defined benefit liability | € 1 | € 1 |  |

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- Definition Defined benefit obligation. + References No definition available. + Details
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- Definition 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. + References No definition available. + Details
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- Definition The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 140 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_140_a&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 57 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_57_a&doctype=Standard -URIDate 2020-01-01 + Details
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