v3.26.1
Long-Duration Insurance Contracts Relating to Life Insurance Operations - Schedule of Liability For Future Policy Benefit Expected Future Policy Benefit Undiscounted Before Reinsurance (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Yen-denominated insurance (First Sector)    
Liability for Future Policy Benefit, Activity [Line Items]    
Expected future gross premiums - Undiscounted ¥ 1,567,367 ¥ 1,551,749
Expected future policy benefits and expenses - Undiscounted 2,621,312 2,532,638
Expected future gross premiums - Discounted 1,297,608 1,362,111
Expected future policy benefits and expenses - Discounted 1,370,583 1,511,436
Yen-denominated insurance (Third Sector)    
Liability for Future Policy Benefit, Activity [Line Items]    
Expected future gross premiums - Undiscounted 2,293,632 2,456,942
Expected future policy benefits and expenses - Undiscounted 2,637,437 2,552,133
Expected future gross premiums - Discounted 1,713,873 2,003,392
Expected future policy benefits and expenses - Discounted 1,344,482 1,659,960
Foreign currency denominated insurance    
Liability for Future Policy Benefit, Activity [Line Items]    
Expected future gross premiums - Undiscounted 583,537 617,771
Expected future policy benefits and expenses - Undiscounted 1,340,021 1,288,727
Expected future gross premiums - Discounted 478,421 493,328
Expected future policy benefits and expenses - Discounted ¥ 495,324 ¥ 442,939