Cash and due from banks at amortized cost - Restricted due from banks at amortized cost (Details) - KRW (₩) ₩ in Millions	Dec. 31, 2025	Dec. 31, 2024
Restricted due from banks at amortized cost [Line Items]
Restricted due from banks at amortized cost, total	₩ 18,259,001	₩ 24,618,870
Denominated in Korean won
Restricted due from banks at amortized cost [Line Items]
Reserve deposits	8,164,072	11,594,266
Other	1,727,588	1,978,415
Restricted due from banks at amortized cost, total	9,891,660	13,572,681
Denominated in foreign currency
Restricted due from banks at amortized cost [Line Items]
Deposits	₩ 8,367,341	₩ 11,046,189

The amount of reserve that is kept in deposit at a central bank to fulfil regulatory reserve requirements.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_112_c&doctype=Standard
-URIDate 2025-03-27

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