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PENSIONS AND OTHER POST-EMPLOYMENT BENEFIT OBLIGATIONS - Narrative (Details) - EUR (€) € in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of defined benefit plans [line items] |  |  |  |  |  |  |
Gain (loss) recognized due to change in benefits | € 2 | € 2 | € 2 | € 2 |  |  |
Other Benefits |  |  |  |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |  |  |  |
Gain (loss) recognized due to change in benefits | € 2 | € 2 | € 2 | € 2 | € 2 | € 3 | € (36)

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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [Refer: Net defined benefit liability (asset); Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 141 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_141_d&doctype=Standard -URIDate 2020-01-01 + Details
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- Details
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