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SHARE-BASED COMPENSATION - Narrative (Details) € / shares in Units, € in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
May 31, 2021 shares | Jul. 31, 2020 shares | Dec. 31, 2021 EUR (€) shares € / shares | Dec. 31, 2020 EUR (€) shares € / shares | Dec. 31, 2019 EUR (€) shares
Share Based Payment Plans [line items] |  |  |  |  |
Expense from share-based payment transactions with employees | € |  |  | € 15 | € 15 | € 16
Antidilutive securities (in shares) |  |  |  | 6,402,289 |
PSUs |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Share based compensation, vesting period |  |  | 3 years |  |
Total shareholder return (TSR) percentage achieved | 182.90% | 186.80% |  |  |
Potential additional shares granted (in shares) | 1,161,718 | 1,458,985 |  |  |
Share price at grant date (in EUR per share) | € / shares |  |  | € 13.90 | € 4.64 |
PSUs | Bottom of range |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Percentage of vesting multiplier |  |  | 0.00% |  |
PSUs | Top of range |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Percentage of vesting multiplier |  |  | 200.00% |  |
RSUs |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Potential additional shares granted (in shares) |  |  | 534,499 | 910,047 |
RSUs | Certain Employees And Chief Financial Officer |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Vesting period on the grant date |  |  | 3 years |  |
Share price at grant date (in EUR per share) | € / shares |  |  | € 13.90 |  |
RSUs | Board Members |  |  |  |  |
Share Based Payment Plans [line items] |  |  |  |  |
Potential additional shares granted (in shares) |  |  | 0 | 0 | 2

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