Customer deposits - Schedule of customer deposits (Details) - EUR (€) € in Millions	Dec. 31, 2023	Dec. 31, 2022
Deposits from customers [abstract]
Current accounts / Overnight deposits	€ 221,773	€ 260,350
Savings accounts	334,296	329,531
Time deposits	92,154	48,524
Other	2,053	2,395
Customer deposits	€ 650,276	€ 640,799

The amount of balances in customers' deposit accounts held by the entity that the entity does not separately disclose in the same statement or note.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2023-03-23

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