Financial instruments (Details) - EUR (€) € in Millions	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Disclosure of fair value measurement of liabilities [line items]
Short-term deposits with maturity of less than three months	€ 315	€ 14	€ 39
Put option to acquire non-controlling interests in joint venture \| Level 3
Disclosure of fair value measurement of liabilities [line items]
Income statement impact from gains (losses) on fair value measurement liabilities	0	0
Fair value \| Level 2
Disclosure of fair value measurement of liabilities [line items]
Derivative financial liabilities	31		28
Short-term deposits with maturity of less than three months	315		39
Not measured at fair value in statement of financial position but for which fair value is disclosed [member] \| Bonds \| Level 1
Disclosure of fair value measurement of liabilities [line items]
Financial liabilities, at fair value	€ 2,962	€ 0	€ 2,998

The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

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No definition available.

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The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

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A classification of cash equivalents representing short-term deposits. [Refer: Cash equivalents]

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