v3.25.2
Insurance contracts in the financial services segment - Summary of Underlying Items of Insurance Contracts Measured Under The Variable Fee Approach and their fair values (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach ¥ 2,926,180 ¥ 2,232,501
Cash and cash equivalents [member]    
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach 35,235 19,411
Japanese national/local government bonds and corporate bonds [member]    
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach 34,936 42,349
Foreign national/local government bonds and corporate bonds [member]    
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach 478,751 312,919
Equity securities [member]    
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach 2,375,201 1,855,432
Other [member]    
Disclosure In Tabular Form Of Underlying Items Of Contracts Measured Under The Variable Fee Approach [Line Items]    
Total fair values of the underlying items of insurance contracts measured under the variable fee approach ¥ 2,057 ¥ 2,390