v3.26.1
Financial Risks - Summary of Value-At-Risk Analysis Measurement Foreign Currency Positions (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Year-end [Member]    
Disclosure of value-at-risk analysis measurement foreign currency positions [Line items]    
Foreign Currency Positions ¥ 497,100 ¥ 465,300
Average [Member]    
Disclosure of value-at-risk analysis measurement foreign currency positions [Line items]    
Foreign Currency Positions 486,275 441,800
Maximum [Member]    
Disclosure of value-at-risk analysis measurement foreign currency positions [Line items]    
Foreign Currency Positions 505,100 465,300
MInimum [Member]    
Disclosure of value-at-risk analysis measurement foreign currency positions [Line items]    
Foreign Currency Positions ¥ 462,700 ¥ 408,500