Contingent Liabilities (Narrative) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2025	Mar. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Allowance for repayment of excess interest	¥ 3,266	¥ 5,439

Allowance for repayment of excess interest established by consumer finance subsidiaries, which was included in Other liabilities.

No definition available.

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