v3.26.1
Financing receivables - Summary of loans receivable reported within Loans receivable or Investments in and advances to affiliated companies (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost ¥ 4,961,518 ¥ 3,846,632
Carried at fair value [1] 2,783,696 2,178,376
Total 7,745,214 6,025,008
Advances to affiliated companies [Member]    
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost 4,000 4,008
Carried at fair value [1] 15,554 4,946
Total 19,554 8,954
Total [Member]    
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost 4,965,518 3,850,640
Carried at fair value [1] 2,799,250 2,183,322
Total 7,764,768 6,033,962
Loans at banks [Member]    
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost 1,177,435 1,045,787
Carried at fair value [1]
Total 1,177,435 1,045,787
Short-term secured margin loans [Member]    
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost 1,134,393 796,936
Carried at fair value [1]
Total 1,134,393 796,936
Corporate loans [Member]    
Schedule of Financing Receivables [Line Items]    
Carried at amortized cost 2,649,690 2,003,909
Carried at fair value [1] 2,783,696 2,178,376
Total ¥ 5,433,386 ¥ 4,182,285
[1] Includes loans receivable and loan commitments carried at fair value through election of the fair value option.