v3.25.2
Insurance contracts in the financial services segment - Summary of insurance revenue explanatory (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Disclosure In Tabular Form Of Insurance Revenue And Changes In Contractual Service Margin By Transition Approach [Line Items]      
Insurance revenue ¥ 622,959 ¥ 586,115 ¥ 554,570
Contractual service margin related to contracts that existed at transition date to which modified retrospective approach has been applied [member]      
Disclosure In Tabular Form Of Insurance Revenue And Changes In Contractual Service Margin By Transition Approach [Line Items]      
Insurance revenue 172,003 185,731 190,199
Contractual service margin related to contracts that existed at transition date to which fair value approach has been applied [member]      
Disclosure In Tabular Form Of Insurance Revenue And Changes In Contractual Service Margin By Transition Approach [Line Items]      
Insurance revenue 29,206 27,079 26,988
Contractual service margin not related to contracts that existed at transition date to which modified retrospective approach or fair value approach has been applied [member]      
Disclosure In Tabular Form Of Insurance Revenue And Changes In Contractual Service Margin By Transition Approach [Line Items]      
Insurance revenue ¥ 421,750 ¥ 373,305 ¥ 337,383