v3.25.2
Employee benefits - Summary of Fair Value of Plan Assets Japanese Plans (Detail) - Japanese Defined Benefit Plans [Member] - JPY (¥)
¥ in Millions
Mar. 31, 2025
Mar. 31, 2024
Disclosure of fair value of plan assets [line items]    
Cash and cash equivalents ¥ 12,192 ¥ 8,390
Equity securities [1] 54,103 56,122
Fixed income:    
Government bonds [2] 11,565 11,211
Corporate bonds [3] 5,241 5,403
Commingled funds [4] 278,892 297,828
Private equity 35,115 40,017
Hedge funds 42,835 45,405
Total 439,943 464,376
Quoted Market Prices in Active Market [Member]    
Disclosure of fair value of plan assets [line items]    
Cash and cash equivalents 12,192 8,390
Equity securities [1] 48,624 50,656
Fixed income:    
Government bonds [2] 382 1
Corporate bonds [3] 18  
Total 61,216 59,047
Unquoted Market Prices in Active Market [Member]    
Disclosure of fair value of plan assets [line items]    
Equity securities [1] 5,479 5,466
Fixed income:    
Government bonds [2] 11,183 11,210
Corporate bonds [3] 5,223 5,403
Commingled funds [4] 278,892 297,828
Private equity 35,115 40,017
Hedge funds 42,835 45,405
Total ¥ 378,727 ¥ 405,329
[1] Represents primarily Japanese equity securities.
[2] Includes approximately 84% and 0% of debt securities issued by Japanese national and local governments, and 16% and 0% of debt securities issued by foreign national and local governments as of the fiscal years ended March 31, 2024 and 2025, respectively.  
[3] Includes debt securities issued by Japanese and foreign corporations and government related agencies.
[4] Commingled funds represent pooled institutional investments, including primarily investment trusts.