v3.26.3
Income and Expenses Relating to Life Insurance Operations - Life Insurance Premiums and Related Investment Income (Detail) - JPY (¥)
¥ in Millions
6 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Net Investment Income [Line Items]    
Total revenue ¥ 1,673,875 ¥ 1,527,599
Life insurance premiums    
Net Investment Income [Line Items]    
Total revenue 253,595 241,599
Life insurance related investment income    
Net Investment Income [Line Items]    
Total revenue [1] 59,146 58,109
Life insurance premiums and related investment income    
Net Investment Income [Line Items]    
Total revenue ¥ 312,741 ¥ 299,708
[1] Life insurance related investment income for the six months ended September 30, 2025 and 2026 include net unrealized holding of a gain of ¥30,360 million and a gain of ¥25,692 million on equity securities held as of September 30, 2025 and 2026, respectively.