Fair Value (Differences between Aggregate Fair Value and Aggregate Remaining Contractual Principal Balance Outstanding) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Option, Quantitative Disclosures [Line Items]
Remaining aggregate contractual amounts outstanding, Financial liabilities	¥ 246,153	¥ 501,982
Fair value	234,909	431,338
Fair value over (under) remaining aggregate contractual amounts outstanding, Financial liabilities	(11,244)	(70,644)
Long-term debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Remaining aggregate contractual amounts outstanding, Financial liabilities	246,153	501,982
Fair value	234,909	431,338
Fair value over (under) remaining aggregate contractual amounts outstanding, Financial liabilities	¥ (11,244)	¥ (70,644)

Aggregate fair value of long-term debt instruments for which the fair value option has been elected.

No definition available.

Name:	mufg_FairValueOptionAggregateFairValueAmountsOutstandingLongTermDebtInstruments
Namespace Prefix:	mufg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Remaining aggregate contractual amount of long-term debt instruments for which the fair value option has been elected.

+ References

No definition available.

+ Details

Name:	mufg_FairValueOptionRemainingAggregateContractualAmountsOutstandingLiabilities
Namespace Prefix:	mufg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of long-term debt instruments that have contractual principal amounts and for which the fair value option has been elected.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

+ Details

Name:	us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-30

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-31

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-32

+ Details

Name:	us-gaap_FairValueOptionQuantitativeDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_LongTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: