Note 26 - Components of Deposits (Detail) - EUR (€) € in Millions	Dec. 31, 2023	Dec. 31, 2022
Components of Deposits [Line Items]
Noninterest-bearing demand deposits	€ 187,078	€ 253,989
Interest-bearing deposits [Abstract]
Demand deposits	162,444	131,726
Time deposits	188,468	158,851
Savings deposits	87,496	84,617
Total interest-bearing deposits	438,408	375,195
Total deposits	€ 625,486	€ 629,183

The amount of balances in customers' term deposits held by the entity.

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