Financial Risk Management and Financial Instruments - Summary of Changes in Warrants Liability (Details) - Warrants - EUR (€) € in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Disclosure Of Changes In Warrants Liability [Line Items] | |||
| Beginning balance | € 346 | € 34 | |
| Issuance of warrant for cash | 9 | € 27 | |
| Non cash changes in profit or loss | |||
| Changes in fair value | (39) | 313 | 7 |
| Effect of changes in foreign exchange rates | 26 | (10) | |
| Ending balance | € 333 | € 346 | € 34 |