Loss per share - Summary of Computation of Loss Per Share (Details) - EUR (€) € / shares in Units, € in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic loss per share
Net loss attributable to owners of the parent	€ (581)	€ (186)	€ (78)
Weighted-average ordinary shares outstanding (in shares)	187,583,307	180,960,579	177,154,405
Basic net loss per share attributable to owners of the parent (euro per share)	€ (3.10)	€ (1.03)	€ (0.44)
Diluted loss per share
Net loss attributable to owners of the parent	€ (581)	€ (186)	€ (78)
Fair value gains on dilutive warrants	0	0	(14)
Net loss used in the computation of diluted loss per share	€ (581)	€ (186)	€ (92)
Weighted-average ordinary shares outstanding
Weighted-average ordinary shares outstanding (in shares)	187,583,307	180,960,579	177,154,405
Warrants (in shares)	0	0	4,055,887
Diluted weighted average ordinary shares (in shares)	187,583,307	180,960,579	181,210,292
Diluted (euro per share)	€ (3.10)	€ (1.03)	€ (0.51)

The number of dilutive potential ordinary shares that relate to the exercise of warrants.

No definition available.

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- Definition

The amount of the fair value adjustment on warrants included in the adjustment made to the numerator in the calculation of diluted earnings per share.

+ References

No definition available.

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- Definition

The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

+ References

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- Definition

The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator) divided by the weighted average number of ordinary shares outstanding during the period (the denominator).

+ References

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- Definition

The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator), divided by the weighted average number of ordinary shares outstanding during the period (the denominator), both adjusted for the effects of all dilutive potential ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

+ References

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- Definition

The profit (loss) attributable to ordinary equity holders of the parent entity, adjusted for the effects of all dilutive potential ordinary shares. [Refer: Profit (loss)]

+ References

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- Definition

The profit (loss) from continuing and discontinued operations attributable to owners of the parent. [Refer: Profit (loss)]

+ References

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- Definition

The number of ordinary shares outstanding at the beginning of the period, adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time-weighting factor.

+ References

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