Contingent Liabilities (Narrative) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Allowance for repayment of excess interest	¥ 12,113	¥ 21,120
Provision (reversal) for repayment of excess interest recognized on Equity in earnings of equity method investee	¥ 0	¥ 23,332	¥ 0

Amount of provision (reversal) for repayment of excess interest recognized on Equity in earnings (losses) of equity method investee.

No definition available.

Name:	mufg_ProvisionReversalForRepaymentOfExcessInterestRecognizedOnEquityInEarningsLossesOfEquityMethodInvestee
Namespace Prefix:	mufg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration