Intangible assets, net - Narrative (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Other intangible assets not yet available for use	€ 37.3	€ 34.0
Impairment charges	€ 11.1	€ 9.2	€ 0.0

The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-SubTopic 30
-Topic 350
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-3

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Name:	us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration