v3.26.1
Guarantees - Balance of guaranteed obligations (Detail) - Parent Company [Member] - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Nomura Global Finance Co Ltd [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] ¥ 2,886,321 ¥ 2,695,770
Nomura International Funding Pte Ltd [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1],[2] 2,671,311 1,986,675
Nomura International plc [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] 1,120,427 808,271
Nomura International plc [Member] | Derivative transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1],[3] 743,119 511,264
Nomura Europe Finance NV [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1],[3] 879,724 821,199
Nomura Corporate Funding Americans LLC [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] 567,421 212,617
Nomura Bank International plc [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] 421,515 408,259
Nomura Global Financial Products Inc [Member] | Derivative transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1],[3] 362,242 498,813
Nomura America Finance LLC [Member] | Borrowings/Medium term notes/Repurchase transactions [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] 342,059 179,734
Others [Member]    
Guarantor Obligations [Line Items]    
Guarantor obligations, current carrying value [1] ¥ 320,558 ¥ 280,572 [3]
[1] Items recognized as bearing substantially the same obligation of a guarantee of liabilities are included in this note.
[2] Includes joint guarantees with Nomura International (Hong Kong) Limited.
[3] Includes joint guarantees with Nomura Securities Co., Ltd.