v3.25.2
Subsequent events - Additional Information (Detail) - JPY (¥)
¥ in Millions, shares in Millions
May 14, 2025
Mar. 31, 2025
Mar. 31, 2024
Disclosure of non-adjusting events after reporting period [line items]      
Accumulated other comprehensive income   ¥ (566,447) ¥ (376,063)
Shares Repurchased [Member]      
Disclosure of non-adjusting events after reporting period [line items]      
Number of shares for repurchase 100    
Total purchase price for repurchase ¥ 250,000    
Period of repurchase start date May 15, 2025    
Period of repurchase end date May 14, 2026    
Major ordinary share transactions [member]      
Disclosure of non-adjusting events after reporting period [line items]      
Percentage of distribution of common share 80.00%    
Disposal of major subsidiary [member]      
Disclosure of non-adjusting events after reporting period [line items]      
Accumulated other comprehensive income ¥ (1,400,000)    
Subsidiary Holding [Member]      
Disclosure of non-adjusting events after reporting period [line items]      
Proportion of ownership interest in subsidiary 20.00%