Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Common Share) (Detail) - JPY (¥) ¥ / shares in Units, shares in Thousands, ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
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| Net income (loss): | |||
| Net income attributable to MHFG common shareholders | ¥ 1,158,031 | ¥ 593,393 | ¥ 912,473 |
| Effect of dilutive securities | |||
| Effect of dilutive securities | 0 | 0 | 0 |
| Net income attributable to common shareholders after assumed conversions | ¥ 1,158,031 | ¥ 593,393 | ¥ 912,473 |
| Shares: | |||
| Weighted average common shares outstanding | 2,484,190 | 2,529,903 | 2,536,775 |
| Effect of dilutive securities: | |||
| Stock options and the common shares of MHFG under the stock compensation programs | 392 | 379 | 325 |
| Weighted average common shares after assumed conversions | 2,484,581 | 2,530,282 | 2,537,100 |
| Earnings per common share: | |||
| Basic net income per common share | ¥ 466.16 | ¥ 234.55 | ¥ 359.7 |
| Diluted net income per common share | ¥ 466.09 | ¥ 234.52 | ¥ 359.65 |
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- Definition Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise stock options, restrictive stock units (RSUs), convertible preferred stock of an employee stock ownership plan (ESOP), and other dilutive convertible securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- References No definition available.
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- Definition Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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