SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impact of Initial Application of IFRS 16 - Leases (Details) - EUR (€) € in Millions	Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of initial application of standards or interpretations [abstract]
Property, plant and equipment	€ 2,084	€ 2,047
Borrowings	€ (1,895)	€ (1,868)	€ (2,056)

The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period. Note that right-of-use assets are not included. [Contrast: Property, plant and equipment including right-of-use assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2023-01-01
-Paragraph 73
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2023-en-r&anchor=para_73_e&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 54
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_54_a&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_PropertyPlantAndEquipment
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant