v3.26.1
Business Developments (Acquisition of TIDLOR Holdings Public Company Limited) (Details) - JPY (¥)
¥ in Millions
1 Months Ended 8 Months Ended 12 Months Ended
Aug. 13, 2025
May 31, 2025
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2025
Aug. 12, 2025
Mar. 31, 2024
Business Developments [Line Items]              
Marketable equity securities included in investment in equity method investees, aggregated market values     ¥ 11,034,755 ¥ 11,034,755 ¥ 7,461,707    
Goodwill (Notes 2 and 6)     566,536 566,536 558,164   ¥ 493,758
Trade names              
Business Developments [Line Items]              
Other     14,050 ¥ 14,050 ¥ 0    
Customer relationships              
Business Developments [Line Items]              
Weighted average amortization period, in years       16 years 16 years    
TIDLOR Holdins Public Company Limited (TIDLOR)              
Business Developments [Line Items]              
Assets acquired ¥ 543,888            
Net loans 464,468            
Liabilities acquired 373,142            
Long-term debt liabilities acquired 346,260            
Noncontrolling interests, recorded on acquisition 125,997            
Marketable equity securities included in investment in equity method investees, aggregated market values 70,304            
Unrealized gain on the contract to purchase equity shares of Shriram Finance Limited (Note 33)     ¥ 12,568        
Business Combination, Achieved in Stages, Preacquisition Equity Interest in Acquiree, Remeasurement, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]     Other non-interest income        
Goodwill (Notes 2 and 6) 62,836            
Intangible assets 17,869            
Revenues     ¥ 74,841        
Earnings or loss of acquiree since acquisition date     7,047        
Acquired loan at fair value at acquisition date 327,795            
Unpaid principal balance 329,474            
Contractual loans not expected to be collected 7,759            
Acquisition related costs     ¥ 151        
Finite-lived intangible assets, purchase accounting adjustments       ¥ 952 ¥ 893    
TIDLOR Holdins Public Company Limited (TIDLOR) | Trade names              
Business Developments [Line Items]              
Intangible asset, indefinite-lived 13,212            
TIDLOR Holdins Public Company Limited (TIDLOR) | Customer relationships              
Business Developments [Line Items]              
Intangible asset, finite-lived ¥ 4,657            
Weighted average amortization period, in years 5 years            
Krungsri | TIDLOR Holdins Public Company Limited (TIDLOR)              
Business Developments [Line Items]              
Ownership percentage           16.33%  
Krungsri | TIDLOR Holdins Public Company Limited (TIDLOR)              
Business Developments [Line Items]              
Number of shares acquired (in shares) 472,914,456            
Consideration transferred ¥ 37,281            
Ngern Tid Lor Public Company Limited (NTL) | Krungsri              
Business Developments [Line Items]              
Conversion of stock, shares converted (in shares)   874,078,998          
Krungsri | TIDLOR Holdins Public Company Limited (TIDLOR)              
Business Developments [Line Items]              
Ownership percentage, parent           46.51%