v3.26.1
Income Taxes - Components by Expiry of the Carryforward of Unused Tax Losses for which Deferred Tax Assets are not Recognized (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Unused tax losses ¥ 566,262 ¥ 436,674
Within 1 year [member]    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Unused tax losses 16,853 12,142
Between 1 and 5 years [member]    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Unused tax losses 204,354 92,042
Between 5 and 20 years [member]    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Unused tax losses 49,376 36,115
Indefinite periods [member]    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Unused tax losses ¥ 295,679 ¥ 296,375