Cash and Deposits with Banks - Summary of Cash and Deposits with Banks (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Cash [abstract]
Cash	¥ 738,248	¥ 915,155
Deposits with banks	73,623,887	75,754,246
Total cash and deposits with banks	¥ 74,362,135	¥ 76,669,401	¥ 78,750,443

The amount of cash balances held at banks.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2025-01-01
-Paragraph 45
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_45&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- Definition

The amount of cash on hand and demand deposits. [Refer: Cash on hand]

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The amount of cash held by the entity. This does not include demand deposits.

+ References

+ Details

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