v3.26.1
Intangible Assets - Changes in Goodwill by Business Segment (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance ¥ 287,514 ¥ 304,564  
Impairment losses 0 (8,032) ¥ 0
Acquisitions 43,898    
Exchange differences (6,321) (7,884)  
Other   (1,134)  
Carrying amount, ending balance 325,091 287,514 304,564
Gross carrying amount [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 332,944 346,962  
Carrying amount, ending balance 370,521 332,944 346,962
Accumulated impairment [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance (45,430) (42,398)  
Carrying amount, ending balance (45,430) (45,430) (42,398)
Retail Business Unit [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 56,952 61,952  
Impairment losses   (5,000)  
Acquisitions 43,898    
Exchange differences    
Other    
Carrying amount, ending balance 100,850 56,952 61,952
Retail Business Unit [member] | Gross carrying amount [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 56,952 61,952  
Carrying amount, ending balance 100,850 56,952 61,952
Retail Business Unit [member] | Accumulated impairment [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance  
Carrying amount, ending balance  
Global Business Unit [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 217,884 229,934  
Impairment losses   (3,032)  
Exchange differences (6,321) (7,884)  
Other   (1,134)  
Carrying amount, ending balance 211,563 217,884 229,934
Global Business Unit [member] | Gross carrying amount [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 220,916 229,934  
Carrying amount, ending balance 214,595 220,916 229,934
Global Business Unit [member] | Accumulated impairment [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance (3,032)  
Carrying amount, ending balance (3,032) (3,032)
Head Office Account and Others [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 12,678 12,678  
Impairment losses    
Exchange differences    
Other    
Carrying amount, ending balance 12,678 12,678 12,678
Head Office Account and Others [member] | Gross carrying amount [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance 55,076 55,076  
Carrying amount, ending balance 55,076 55,076 55,076
Head Office Account and Others [member] | Accumulated impairment [member]      
Disclosure of reconciliation of changes in goodwill [line items]      
Carrying amount, beginning balance (42,398) (42,398)  
Carrying amount, ending balance ¥ (42,398) ¥ (42,398) ¥ (42,398)