Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Non-cancellable Operating Leases (Details) - EUR (€) |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Disclosure Of Finance Leases And Operating Leases By Lessee [Line Items] | ||
| Minimum lease payments under non-cancellable lease | € 833,000,000 | € 769,000,000 |
| Not Later Than One Year | ||
| Disclosure Of Finance Leases And Operating Leases By Lessee [Line Items] | ||
| Minimum lease payments under non-cancellable lease | 62,000,000 | 47,000,000 |
| Later Than One Year But Not More Than 5 Years | ||
| Disclosure Of Finance Leases And Operating Leases By Lessee [Line Items] | ||
| Minimum lease payments under non-cancellable lease | 288,000,000 | 244,000,000 |
| Later Than Five Years | ||
| Disclosure Of Finance Leases And Operating Leases By Lessee [Line Items] | ||
| Minimum lease payments under non-cancellable lease | € 483,000,000 | € 478,000,000 |