v3.26.1
Business Developments (Acquisition of AlbaCore Capital Group) (Details) - JPY (¥)
¥ in Millions
5 Months Ended 12 Months Ended
Nov. 14, 2023
Mar. 31, 2024
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Business Developments [Line Items]          
Goodwill   ¥ 493,758 ¥ 566,536 ¥ 558,164 ¥ 493,758
Customer relationships          
Business Developments [Line Items]          
Weighted average amortization period, in years     16 years 16 years  
Albacore Capital Group          
Business Developments [Line Items]          
Percentage of voting interests acquired 75.00%        
Consideration transferred ¥ 49,266        
Contingent consideration 17,979        
Acquisition related costs         2,599
Assets acquired 33,583        
Cash and bank deposits acquired 6,448        
Intangible assets 23,709        
Liabilities acquired 12,187        
Deferred tax liabilities acquired 5,927        
Goodwill ¥ 63,063        
Weighted average amortization period, in years 15 years 8 months 12 days        
Noncontrolling interests, recorded on acquisition ¥ 17,214        
Revenues   1,107      
Earnings or loss of acquiree since acquisition date   ¥ (155)      
Finite-lived intangible assets, purchase accounting adjustments         ¥ 1,426
Albacore Capital Group | Customer relationships          
Business Developments [Line Items]          
Intangible assets ¥ 22,478        
Weighted average amortization period, in years 16 years