v3.26.1
Business Developments (Acquisition of Link Administration Holdings Limited) (Details) - JPY (¥)
¥ in Millions
10 Months Ended 12 Months Ended
May 16, 2024
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Business Developments [Line Items]          
Goodwill   ¥ 558,164 ¥ 566,536 ¥ 558,164 ¥ 493,758
Intangible assets subject to amortization acquired     370,047 403,938  
Customer relationships          
Business Developments [Line Items]          
Intangible assets subject to amortization acquired     ¥ 20,988 ¥ 68,010  
Weighted average amortization period, in years     16 years 16 years  
Link Administration Holdings Limited          
Business Developments [Line Items]          
Percentage of voting interests acquired 100.00%        
Payments to acquire businesses ¥ 113,524        
Acquisition related costs       ¥ 3,856  
Assets acquired 153,019        
Cash and bank deposits acquired 21,586        
Intangible assets 45,141        
Liabilities acquired 188,316        
Long-term debt liabilities acquired 118,441        
Goodwill ¥ 149,782        
Weighted average amortization period, in years 17 years 9 months 18 days        
Revenues   67,676      
Loss of acquiree since acquisition date   ¥ 3,919      
Finite-lived intangible assets, purchase accounting adjustments       ¥ 2,443 ¥ 2,281
Link Administration Holdings Limited | Customer relationships          
Business Developments [Line Items]          
Intangible assets ¥ 67,283