Summary of significant accounting policies - Income Tax Expense (Details) - EUR (€)	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Detailed Information About Income Taxes [Line Items]
Deferred tax expense	€ (958,000,000)	€ (768,000,000)	€ (350,000,000)
Temporary differences subject to GILTI
Disclosure Of Detailed Information About Income Taxes [Line Items]
Deferred tax expense	€ 0

The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2023-01-01
-Paragraph 81
-Subparagraph g
-Clause ii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2023-en-r&anchor=para_81_g_ii&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_DeferredTaxExpenseIncome
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration