v3.26.1
Income Taxes (Net Operating Losses Carryforwards by Expiration Date) (Detail)
¥ in Millions
Mar. 31, 2026
JPY (¥)
 [1],[2]
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards ¥ 416,000
2027  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards 0
2028  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards 0
2029  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards 0
2030  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards 0
2031  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards 0
2032 and thereafter  
Operating Loss Carryforwards [Line Items]  
Net operating loss carryforwards ¥ 415 [3]
[1] Net operating loss carryforwards related to Japanese local taxes at MHBK amounted to ¥80 billion (tax-effected ¥3 billion) as of March 31, 2026 and are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034.
[2] Net operating loss carryforwards related to Japanese local taxes at MHFG amounted to ¥518 billion (tax-effected ¥25 billion) as of March 31, 2026 and are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032.
[3] Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom.