v3.25.2
Financial instruments - Summary of Changes in Unrealized Gains (Losses) Recognized in Net Income for Level 3 Assets and Liabilities (Detail) - Recurring fair value measurement [member] - Level 3 of fair value hierarchy [member] - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Contingent Considerations [Member] | Financial liabilities required to be measured at FVPL [member]    
Liabilities:    
Financial liabilities required to be measured at FVPL ¥ (1,223) ¥ (1,488)
Redeemable Non Controlling Interests [Member] | Financial liabilities designated to be measured at FVPL [member]    
Liabilities:    
Financial liabilities required to be measured at FVPL 600 3,270
Equity Contracts [Member] | Financial liabilities required to be measured at FVPL [member]    
Liabilities:    
Financial liabilities required to be measured at FVPL (121,082)  
Debt securities [member] | Investment funds [member] | Financial assets required to be measured at FVPL [member]    
Assets:    
Financial assets (1,801) 3,887
Debt securities [member] | Foreign Corporate Bonds [Member] | Financial assets required to be measured at FVPL [member]    
Assets:    
Financial assets (39) 171
Debt securities [member] | Foreign Corporate Bonds [Member] | Financial assets designated to be measured at FVPL [member]    
Assets:    
Financial assets 119 646
Debt securities [member] | Foreign Corporate Bonds [Member] | Financial assets required to be measured at FVOCI [member]    
Assets:    
Financial assets (939) 1,315
Debt securities [member] | Securitized Products [Member] | Financial assets required to be measured at FVOCI [member]    
Assets:    
Financial assets (1,610) 1,509
Debt securities [member] | Japanese Corporate Bonds [Member] | Financial assets required to be measured at FVOCI [member]    
Assets:    
Financial assets 9 8
Equity securities [member] | Financial assets required to be measured at FVPL [member]    
Assets:    
Financial assets ¥ (840) 495
Derivatives [member] | Equity Contracts [Member] | Financial assets required to be measured at FVPL [member]    
Assets:    
Financial assets   ¥ (2,816)