v3.26.3
Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Non-Accrual of Financial Assets (Detail) - JPY (¥)
¥ in Millions
 6 Months Ended 12 Months Ended
Sep. 30, 2026
Mar. 31, 2026
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance ¥ 97,138 ¥ 98,052
Ending balance 93,454 97,138
Interest income recognized during the reporting period 4 13
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 2,508 2,539
Consumer borrowers | Real estate loans | Japan    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 0 249
Ending balance   0
Interest income recognized during the reporting period   4
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income   0
Consumer borrowers | Real estate loans | Overseas    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 8,895 4,976
Ending balance 10,486 8,895
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 132 137
Consumer borrowers | Other | Japan    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 0 86
Ending balance 0 0
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 0 0
Consumer borrowers | Other | Overseas    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 982 2,373
Ending balance 1,048 982
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 7 3
Corporate borrowers | Non-recourse Loans | Overseas    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 11,477 3,831
Ending balance 9,637 11,477
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 0 0
Corporate borrowers | Other than non-recourse loans | Real estate companies | Japan    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 0 29
Ending balance 0 0
Interest income recognized during the reporting period 4 9
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 0 0
Corporate borrowers | Other than non-recourse loans | Real estate companies | Overseas    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 2,181 3,417
Ending balance 2,080 2,181
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 0 0
Corporate borrowers | Other than non-recourse loans | Commercial, industrial and other companies | Japan    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 541 520
Ending balance 156 541
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 0 0
Corporate borrowers | Other than non-recourse loans | Commercial, industrial and other companies | Overseas    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 46,642 60,629
Ending balance 38,086 46,642
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income 2,369 2,399
Loans to Equity Method Investees    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 0 1,345
Ending balance   0
Interest income recognized during the reporting period   0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income   0
Net investment in leases    
Disclosure Detail Of Non Accrual Of Financial Assets [Line Items]    
Beginning balance 26,420 20,597
Ending balance 31,961 26,420
Interest income recognized during the reporting period 0 0
Balance not associated allowance for credit losses among financial assets measured at amortized cost, which is suspending recognition of income ¥ 0 ¥ 0