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Estimated Fair Value of Financial Instruments (Information about Carrying Amount of Financial Instruments Reported in Consolidated Balance Sheets and Related Market or Fair Value) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2025	Mar. 31, 2025
Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment funds	¥ 140,587	¥ 118,666

X

- Definition

Investment funds measured at net assets value per share not included in equity securities.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

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- 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

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