Segment information - Summary of Operating Results by Geographical Areas (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of geographical areas [line items]
Turnover	€ 60,761	€ 59,604	€ 60,073
Non-current assets	53,541	51,084	52,201
United Kingdom
Disclosure of geographical areas [line items]
Turnover	2,646	2,523	2,498
Non-current assets	3,830	3,567	3,621
United States
Disclosure of geographical areas [line items]
Turnover	12,515	12,250	12,122
Non-current assets	19,715	18,205	18,109
India
Disclosure of geographical areas [line items]
Turnover	6,677	6,691	6,872
Non-current assets	6,700	6,436	6,500
Others
Disclosure of geographical areas [line items]
Turnover	38,923	38,140	38,581
Non-current assets	€ 23,296	€ 22,876	€ 23,971

The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 28
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 23
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23_a&doctype=Standard
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 32
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_32&doctype=Standard
-URIDate 2024-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 33
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_33_a&doctype=Standard
-URIDate 2024-03-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 34
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_34&doctype=Standard
-URIDate 2024-03-27

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 5
-IssueDate 2024-01-01
-Paragraph 33
-Subparagraph b
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2024-en-r&anchor=para_33_b_i&doctype=Standard
-URIDate 2024-03-27

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B12
-Subparagraph b
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B10
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 82
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_82_a&doctype=Standard
-URIDate 2024-03-27

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 103
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_103&doctype=Standard
-URIDate 2024-03-27

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 102
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_102&doctype=Standard
-URIDate 2024-03-27

+ Details