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INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) - EUR (€) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Goodwill | € 417,000,000 | € 455,000,000 | € 422,000,000
P&ARP |  |  |
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Goodwill | 410,000,000 |  |
Carrying value | 1,203,000,000 |  |
Recoverable value | 2,290,000,000 |  |
Goodwill impairment | € 0 |  |
Increase discount rate | 7.00% |  |
Decrease in the perpetual growth | 9.00% |  |
Decrease in cash flows | 40.00% |  |
P&ARP | Bottom of range |  |  |
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Discount rate to estimate normative cash flows | 9.00% |  |
P&ARP | Top of range |  |  |
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Long term growth rate used to estimate normative cash flow | 1.50% |  |
A&T |  |  |
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Goodwill | € 5,000,000 |  |
Long term growth rate used to estimate normative cash flow | 1.50% |  |
Discount rate to estimate normative cash flows | 9.00% |  |
AS&I |  |  |
Disclosure of reconciliation of changes in intangible assets and goodwill [line items] |  |  |
Goodwill | € 2,000,000 |  |
Discount rate to estimate normative cash flows | 9.00% |  |

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