Income Tax - Summary of Reconciliation of Net Deferred Tax (Details) - EUR (€) € in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Reconciliation Of Changes In Deferred Tax Liability Asset [Abstract] | |||
| At January 1 | € 6 | € 3 | € 4 |
| Movement recognized in consolidated statement of operations | 136 | 5 | 1 |
| Movement recognized in consolidated statement of changes in equity and other comprehensive income | (136) | 2 | (2) |
| Movement due to acquisition | 0 | (4) | 0 |
| At December 31 | € 6 | € 6 | € 3 |