v3.26.3
Long-Duration Insurance Contracts Relating to Life Insurance Operations - Schedule of Liability For Future Policy Benefit, Weighted Average Discount Rates (Detail)
Sep. 30, 2026
Mar. 31, 2026
Yen-denominated insurance (First Sector)    
Liability for Future Policy Benefit, Activity [Line Items]    
Weighted average of the original discount rates 2.10% 1.90%
Weighted average of the current discount rates 4.40% 4.00%
Yen-denominated insurance (Third Sector)    
Liability for Future Policy Benefit, Activity [Line Items]    
Weighted average of the original discount rates 1.80% 1.70%
Weighted average of the current discount rates 4.60% 4.20%
Foreign currency denominated insurance    
Liability for Future Policy Benefit, Activity [Line Items]    
Weighted average of the original discount rates 3.50% 3.40%
Weighted average of the current discount rates 6.60% 6.00%