v3.26.1
Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Allowance for Credit Losses for Installment Loans (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance ¥ 56,769 ¥ 58,110 ¥ 65,373
Provision (Reversal) 24,774 13,253 20,963
Allowance for credit losses on acquired financial assets at acquisition 8,124 7,507 47,676
Charge-offs (19,901) (19,304) (63,473)
Recoveries 1,026 712 893
Other 9,402 (3,509) (13,322)
Ending balance 80,194 56,769 58,110
Collective (pool) assessment 35,462 32,890 37,162
Individual assessment 44,732 23,879 20,948
Consumer | Real estate loans | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 2,891 3,203 4,092
Provision (Reversal) 180 (317) (712)
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (130) (62) (218)
Recoveries 36 66 151
Other (153) 1 (110)
Ending balance 2,824 2,891 3,203
Collective (pool) assessment 2,615 2,609 2,893
Individual assessment 209 282 310
Consumer | Real estate loans | Overseas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 1,679 581 446
Provision (Reversal) 262 1,202 94
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (202) 0 (6)
Recoveries 0 1 1
Other 80 (105) 46
Ending balance 1,819 1,679 581
Collective (pool) assessment 367 505 526
Individual assessment 1,452 1,174 55
Consumer | Card loans | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 36 12 9,022
Provision (Reversal) (7) 13 101
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs 0 0 (918)
Recoveries 6 11 10
Other 0 0 (8,203)
Ending balance 35 36 12
Collective (pool) assessment 35 36 12
Individual assessment 0 0 0
Consumer | Other | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 90 91 7,759
Provision (Reversal) (5) (8) 5,313
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs 0 0 (3,856)
Recoveries 2 7 7
Other (84) 0 (9,132)
Ending balance 3 90 91
Collective (pool) assessment 3 6 6
Individual assessment 0 84 85
Consumer | Other | Overseas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 3,048 3,060 1,889
Provision (Reversal) 2,203 2,996 3,166
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (3,720) (3,237) (2,736)
Recoveries 337 453 476
Other 224 (224) 265
Ending balance 2,092 3,048 3,060
Collective (pool) assessment 1,449 1,355 1,762
Individual assessment 643 1,693 1,298
Corporate | Non-recourse Loans | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 462 429 253
Provision (Reversal) 126 33 176
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs 0 0 0
Recoveries 0 0 0
Other (6) 0 0
Ending balance 582 462 429
Collective (pool) assessment 582 462 429
Individual assessment 0 0 0
Corporate | Non-recourse Loans | Overseas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 2,593    
Provision (Reversal) 2,969    
Allowance for credit losses on acquired financial assets at acquisition 0    
Charge-offs (1,264)    
Recoveries 0    
Other 1,337    
Ending balance 5,635 2,593  
Collective (pool) assessment 2,224    
Individual assessment 3,411    
Corporate | Non-recourse Loans | The Americas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 2,593 1,718 1,494
Provision (Reversal)   1,066 74
Allowance for credit losses on acquired financial assets at acquisition   0 0
Charge-offs   (150) (55)
Recoveries   0 0
Other   (41) 205
Ending balance   2,593 1,718
Collective (pool) assessment   1,548 660
Individual assessment   1,045 1,058
Corporate | Other than non-recourse loans | Real estate companies | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 908 975 777
Provision (Reversal) 192 (14) 176
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (18) (78) (4)
Recoveries 25 26 26
Other (84) (1) 0
Ending balance 1,023 908 975
Collective (pool) assessment 1,021 877 889
Individual assessment 2 31 86
Corporate | Other than non-recourse loans | Real estate companies | Overseas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 2,046 1,549 1,007
Provision (Reversal) 320 682 430
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs 0 0 0
Recoveries 0 0 0
Other (876) (185) 112
Ending balance 1,490 2,046 1,549
Collective (pool) assessment 519 764 1,045
Individual assessment 971 1,282 504
Corporate | Other than non-recourse loans | Commercial, industrial and other companies loans | Japan      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 1,078 857 1,152
Provision (Reversal) 167 359 (44)
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (24) (146) (281)
Recoveries 43 7 9
Other (75) 1 21
Ending balance 1,189 1,078 857
Collective (pool) assessment 691 586 722
Individual assessment 498 492 135
Corporate | Other than non-recourse loans | Commercial, industrial and other companies loans | Overseas      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 20,063 25,824 19,132
Provision (Reversal) 11,799 1,094 8,702
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (3,067) (4,048) (4,762)
Recoveries 197 34 176
Other 1,633 (2,841) 2,576
Ending balance 30,625 20,063 25,824
Collective (pool) assessment 11,946 11,919 16,061
Individual assessment 18,679 8,144 9,763
Loans to Equity Method Investees      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 1,512 878 650
Provision (Reversal) (169) 954 99
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (1,439) (255) 0
Recoveries 2 0 0
Other 94 (65) 129
Ending balance 0 1,512 878
Collective (pool) assessment 0 167 422
Individual assessment 0 1,345 456
Purchased loans      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 1,342 1,133 1,148
Provision (Reversal) 322 80 13
Allowance for credit losses on acquired financial assets at acquisition 3,633 7,507 47,676
Charge-offs (3,763) (7,547) (47,722)
Recoveries 11 2 2
Other 5,943 167 16
Ending balance 7,488 1,342 1,133
Collective (pool) assessment 133 521 548
Individual assessment 7,355 821 585
Net investment in leases      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 18,122 16,780 15,719
Provision (Reversal) 4,933 4,934 3,064
Allowance for credit losses on acquired financial assets at acquisition 0 0 0
Charge-offs (4,938) (3,505) (2,635)
Recoveries 365 91 26
Other 1,425 (178) 606
Ending balance 19,907 18,122 16,780
Collective (pool) assessment 13,218 11,236 10,866
Individual assessment 6,689 6,886 5,914
Installment loans and net investment in leases      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 55,870 57,090 64,540
Provision (Reversal) 23,292 13,074 20,652
Allowance for credit losses on acquired financial assets at acquisition 3,633 7,507 47,676
Charge-offs (18,565) (19,028) (63,193)
Recoveries 1,024 698 884
Other 9,458 (3,471) (13,469)
Ending balance 74,712 55,870 57,090
Collective (pool) assessment 34,803 32,591 36,841
Individual assessment 39,909 23,279 20,249
Other financial assets measured at amortized cost      
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning balance 899 1,020 833
Provision (Reversal) 1,482 179 311
Allowance for credit losses on acquired financial assets at acquisition 4,491 0 0
Charge-offs (1,336) (276) (280)
Recoveries 2 14 9
Other (56) (38) 147
Ending balance 5,482 899 1,020
Collective (pool) assessment 659 299 321
Individual assessment ¥ 4,823 ¥ 600 ¥ 699