v3.26.1
Income and Expenses Relating to Life Insurance Operations - Gains or Losses Relating to Variable Annuity and Variable Life Insurance Contracts (Detail) - Variable Annuity and Variable Life Insurance Contracts - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Life insurance premiums and related investment income      
Net realized and unrealized gains or losses from investment assets ¥ 33,290 ¥ (3,496) ¥ 40,821
Net gains or losses from derivative contracts ¥ (1,559) ¥ (372) ¥ (3,568)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Unrealized Gains Loss On Derivative Instruments Unrealized Gains Loss On Derivative Instruments Unrealized Gains Loss On Derivative Instruments
Life insurance costs      
Changes in the fair value of the policy liabilities and policy account balances ¥ 2,041 ¥ (30,998) ¥ 3,208
Insurance costs recognized for insurance and annuity payouts as a result of insured events 23,553 23,706 26,997
Changes in the fair value of the reinsurance contracts 1,423 200 1,890
Futures      
Life insurance premiums and related investment income      
Net gains or losses from derivative contracts (1,433) (262) (3,046)
Foreign exchange contracts      
Life insurance premiums and related investment income      
Net gains or losses from derivative contracts ¥ (126) ¥ (110) ¥ (522)