Financial liabilities at fair value through profit or loss - Additional information (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Disclosure of fair value measurement of liabilities [abstract]
Fair value of financial liability, attributable to changes in credit risk of liability	€ (34)	€ (75)
Financial liabilities designated at fair value through profit or loss to pay at maturity to the holders	9,957	8,408
Designated at fair value through profit or loss	€ 55,400	€ 50,883

The increase (decrease) in the fair value of a financial liability that is attributable to changes in the credit risk of that liability. [Refer: Credit risk [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 10A
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_10A_a&doctype=Standard
-URIDate 2023-03-23

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount by which the carrying amount of a financial liability is more (less) than the amount that the entity would be contractually required to pay at maturity to the holder of the obligation. [Refer: Carrying amount [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 10
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_10_b&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 10A
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_10A_b&doctype=Standard
-URIDate 2023-03-23

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of financial liabilities at fair value through profit or loss that were designated as such upon initial recognition or subsequently. [Refer: At fair value [member]; Financial liabilities at fair value through profit or loss]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 8
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_8_e&doctype=Standard
-URIDate 2023-03-23

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant