Financial Risk Management and Financial Instruments - Summary of Liquidity Position in Terms of Available Cash and Cash Equivalents and Short Term Investments (Details) - EUR (€) € in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Disclosure Of Liquidity Risk [Line Items] | ||
| Short term investments | € 915 | € 1,032 |
| Liquidity Position | ||
| Disclosure Of Liquidity Risk [Line Items] | ||
| Short term investments | 915 | 1,032 |
| Short term deposits | 307 | 122 |
| Cash at bank and on hand | 584 | 355 |
| Total surplus liquidity | 1,806 | 1,509 |
| Liquidity position | € 1,806 | € 1,509 |