v3.26.3
Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Origination Years of Financial Assets (Detail) - JPY (¥)
¥ in Millions
 6 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Mar. 31, 2026
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) ¥ 2 ¥ 129  
One year ago (Gross write-offs) 372 497  
Two years ago (Gross write-offs) 1,397 1,312  
Three years ago (Gross write-offs) 1,226 821  
Four years ago (Gross write-offs) 500 172  
Prior (Gross write-offs) 9,245 5,428  
Total financing receivables 2,487,406   ¥ 2,527,163
Total financing receivables (Gross write-offs) 12,742 8,359  
Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 552,690   1,023,872
One year ago 781,049   631,829
Two years ago 487,168   318,049
Three years ago 227,709   155,169
Four years ago 132,654   143,750
Prior 223,955   166,633
Total financing receivables 2,405,225   2,439,302
Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 4,309   5,251
One year ago 9,437   12,390
Two years ago 11,304   18,799
Three years ago 17,074   16,270
Four years ago 15,089   16,505
Prior 38,382   32,685
Total financing receivables 95,595   101,900
Consumer borrowers      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 2 9  
One year ago (Gross write-offs) 312 492  
Two years ago (Gross write-offs) 321 549  
Three years ago (Gross write-offs) 126 217  
Four years ago (Gross write-offs) 103 31  
Prior (Gross write-offs) 330 66  
Total financing receivables 72,264   79,093
Total financing receivables (Gross write-offs) 1,194 1,364  
Consumer borrowers | Real estate loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 0  
One year ago (Gross write-offs) 0 0  
Two years ago (Gross write-offs) 0 0  
Three years ago (Gross write-offs) 0 0  
Four years ago (Gross write-offs) 0 14  
Prior (Gross write-offs) 290 64  
Total financing receivables 33,638   38,119
Total financing receivables (Gross write-offs) 290 78  
Consumer borrowers | Other loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 2 9  
One year ago (Gross write-offs) 312 492  
Two years ago (Gross write-offs) 321 549  
Three years ago (Gross write-offs) 126 217  
Four years ago (Gross write-offs) 103 17  
Prior (Gross write-offs) 40 2  
Total financing receivables 38,626   40,974
Total financing receivables (Gross write-offs) 904 1,286  
Consumer borrowers | Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 11,137   21,929
One year ago 16,595   12,499
Two years ago 8,623   7,687
Three years ago 4,840   6,318
Four years ago 4,738   6,619
Prior 14,733   11,391
Total financing receivables 60,666   66,443
Consumer borrowers | Performing | Real estate loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 517   1,441
One year ago 1,375   1,404
Two years ago 1,274   2,243
Three years ago 1,995   3,806
Four years ago 3,379   6,420
Prior 14,583   11,341
Total financing receivables 23,123   26,655
Consumer borrowers | Performing | Other loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 10,620   20,488
One year ago 15,220   11,095
Two years ago 7,349   5,444
Three years ago 2,845   2,512
Four years ago 1,359   199
Prior 150   50
Total financing receivables 37,543   39,788
Consumer borrowers | Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 73   359
One year ago 494   3,314
Two years ago 2,834   2,154
Three years ago 2,215   4,879
Four years ago 4,331   1,235
Prior 1,651   709
Total financing receivables 11,598   12,650
Consumer borrowers | Non-Performing | Real estate loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 28   103
One year ago 108   2,912
Two years ago 2,615   1,858
Three years ago 1,975   4,655
Four years ago 4,142   1,231
Prior 1,647   705
Total financing receivables 10,515   11,464
Consumer borrowers | Non-Performing | Other loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 45   256
One year ago 386   402
Two years ago 219   296
Three years ago 240   224
Four years ago 189   4
Prior 4   4
Total financing receivables 1,083   1,186
Corporate borrowers      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 120  
One year ago (Gross write-offs) 11 1  
Two years ago (Gross write-offs) 496 364  
Three years ago (Gross write-offs) 558 30  
Four years ago (Gross write-offs) 37 28  
Prior (Gross write-offs) 7,578 1,449  
Total financing receivables 1,159,688   1,179,343
Total financing receivables (Gross write-offs) 8,680 1,992  
Corporate borrowers | Non-recourse Loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 0    
Three years ago (Gross write-offs) 0    
Four years ago (Gross write-offs) 0    
Prior (Gross write-offs) 0    
Total financing receivables 48,927   81,084
Total financing receivables (Gross write-offs) 0    
Corporate borrowers | Non-recourse Loans | The Americas      
Financing Receivable, Recorded Investment [Line Items]      
Total financing receivables     200,308
Corporate borrowers | Non-recourse Loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 0    
Three years ago (Gross write-offs) 0    
Four years ago (Gross write-offs) 0    
Prior (Gross write-offs) 0    
Total financing receivables 133,844    
Total financing receivables (Gross write-offs) 0    
Corporate borrowers | Other than non-recourse loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs)   0  
One year ago (Gross write-offs)   0  
Two years ago (Gross write-offs)   0  
Three years ago (Gross write-offs)   0  
Four years ago (Gross write-offs)   0  
Prior (Gross write-offs)   0  
Total financing receivables (Gross write-offs)   0  
Corporate borrowers | Real estate companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 0    
Three years ago (Gross write-offs) 0    
Four years ago (Gross write-offs) 0    
Prior (Gross write-offs) 0    
Total financing receivables 128,660   118,727
Total financing receivables (Gross write-offs) 0    
Corporate borrowers | Real estate companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 0    
Three years ago (Gross write-offs) 407    
Four years ago (Gross write-offs) 19    
Prior (Gross write-offs) 648    
Total financing receivables 91,163   61,853
Total financing receivables (Gross write-offs) 1,074    
Corporate borrowers | Commercial, industrial and other companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 393    
Three years ago (Gross write-offs) 0    
Four years ago (Gross write-offs) 0    
Prior (Gross write-offs) 0    
Total financing receivables 197,666   191,880
Total financing receivables (Gross write-offs) 393    
Corporate borrowers | Commercial, industrial and other companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 120  
One year ago (Gross write-offs) 11 1  
Two years ago (Gross write-offs) 103 364  
Three years ago (Gross write-offs) 151 30  
Four years ago (Gross write-offs) 18 28  
Prior (Gross write-offs) 6,930 1,449  
Total financing receivables 559,428   525,491
Total financing receivables (Gross write-offs) 7,213 1,992  
Corporate borrowers | Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 282,502   508,886
One year ago 369,575   290,116
Two years ago 214,994   107,370
Three years ago 73,746   50,657
Four years ago 57,630   89,236
Prior 110,234   71,133
Total financing receivables 1,108,681   1,117,398
Corporate borrowers | Performing | Non-recourse Loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 0   26,423
One year ago 21,747   40,018
Two years ago 23,213   5,391
Three years ago 1,201   0
Four years ago 0   6,394
Prior 2,766   2,858
Total financing receivables 48,927   81,084
Corporate borrowers | Performing | Non-recourse Loans | The Americas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year     89,661
One year ago     61,545
Two years ago     23,222
Three years ago     7,398
Four years ago     2,037
Prior     4,439
Total financing receivables     188,302
Corporate borrowers | Performing | Non-recourse Loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 3,675    
One year ago 34,910    
Two years ago 49,587    
Three years ago 15,359    
Four years ago 14,239    
Prior 5,817    
Total financing receivables 123,587    
Corporate borrowers | Performing | Real estate companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 52,025   76,450
One year ago 45,803   21,982
Two years ago 16,752   9,284
Three years ago 5,578   1,896
Four years ago 935   1,639
Prior 7,567   7,457
Total financing receivables 128,660   118,708
Corporate borrowers | Performing | Real estate companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 39,859   46,394
One year ago 37,664   5,163
Two years ago 5,774   1,147
Three years ago 1,057   1,120
Four years ago 1,069   0
Prior 3,660   5,848
Total financing receivables 89,083   59,672
Corporate borrowers | Performing | Commercial, industrial and other companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 58,916   97,781
One year ago 62,715   41,003
Two years ago 34,571   27,802
Three years ago 22,308   8,018
Four years ago 6,155   8,374
Prior 12,769   8,233
Total financing receivables 197,434   191,211
Corporate borrowers | Performing | Commercial, industrial and other companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 128,027   172,177
One year ago 166,736   120,405
Two years ago 85,097   40,524
Three years ago 28,243   32,225
Four years ago 35,232   70,792
Prior 77,655   42,298
Total financing receivables 520,990   478,421
Corporate borrowers | Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 151   1,276
One year ago 2,691   3,184
Two years ago 2,034   9,835
Three years ago 7,982   7,692
Four years ago 6,984   13,814
Prior 31,165   26,144
Total financing receivables 51,007   61,945
Corporate borrowers | Non-Performing | Non-recourse Loans | The Americas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year     0
One year ago     79
Two years ago     4,656
Three years ago     855
Four years ago     1,065
Prior     5,351
Total financing receivables     12,006
Corporate borrowers | Non-Performing | Non-recourse Loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 37    
One year ago 0    
Two years ago 87    
Three years ago 4,675    
Four years ago 1,332    
Prior 4,126    
Total financing receivables 10,257    
Corporate borrowers | Non-Performing | Real estate companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year     0
One year ago     19
Two years ago     0
Three years ago     0
Four years ago     0
Prior     0
Total financing receivables     19
Corporate borrowers | Non-Performing | Real estate companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 0   0
One year ago 0   0
Two years ago 0   440
Three years ago 0   1,586
Four years ago 782   63
Prior 1,298   92
Total financing receivables 2,080   2,181
Corporate borrowers | Non-Performing | Commercial, industrial and other companies | Other than non-recourse loans | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 15   14
One year ago 4   411
Two years ago 5   47
Three years ago 42   116
Four years ago 85   11
Prior 81   70
Total financing receivables 232   669
Corporate borrowers | Non-Performing | Commercial, industrial and other companies | Other than non-recourse loans | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 99   1,262
One year ago 2,687   2,675
Two years ago 1,942   4,692
Three years ago 3,265   5,135
Four years ago 4,785   12,675
Prior 25,660   20,631
Total financing receivables 38,438   47,070
Loans to Equity Method Investees      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0    
One year ago (Gross write-offs) 0    
Two years ago (Gross write-offs) 0    
Three years ago (Gross write-offs) 0    
Four years ago (Gross write-offs) 0    
Prior (Gross write-offs) 0    
Total financing receivables 24,615   21,236
Total financing receivables (Gross write-offs) 0    
Loans to Equity Method Investees | Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 3,543   3,032
One year ago 3,053   573
Two years ago 573   585
Three years ago 588   2,005
Four years ago 1,970   21
Prior 14,888   15,020
Total financing receivables 24,615   21,236
Loans to Equity Method Investees | Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year     0
One year ago     0
Two years ago     0
Three years ago     0
Four years ago     0
Prior     0
Total financing receivables     0
Purchased loans      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 0  
One year ago (Gross write-offs) 0 0  
Two years ago (Gross write-offs) 0 0  
Three years ago (Gross write-offs) 0 0  
Four years ago (Gross write-offs) 0 0  
Prior (Gross write-offs) 326 3,659  
Total financing receivables (Gross write-offs) 326 3,659  
Purchased loans | Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 0   0
One year ago 0   792
Two years ago 763   0
Three years ago 0   0
Four years ago 0   0
Prior 12,428   13,019
Total financing receivables 13,191   13,811
Purchased loans | Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 0   0
One year ago 0   0
Two years ago 0   0
Three years ago 0   0
Four years ago 0   0
Prior 223   228
Total financing receivables 223   228
Net investment in leases      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 0  
One year ago (Gross write-offs) 49 4  
Two years ago (Gross write-offs) 580 399  
Three years ago (Gross write-offs) 542 574  
Four years ago (Gross write-offs) 360 113  
Prior (Gross write-offs) 1,011 254  
Total financing receivables 1,230,839   1,247,491
Total financing receivables (Gross write-offs) 2,542 1,344  
Net investment in leases | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 0  
One year ago (Gross write-offs) 8 2  
Two years ago (Gross write-offs) 36 39  
Three years ago (Gross write-offs) 72 117  
Four years ago (Gross write-offs) 92 93  
Prior (Gross write-offs) 184 238  
Total financing receivables 610,041   619,333
Total financing receivables (Gross write-offs) 392 489  
Net investment in leases | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year (Gross write-offs) 0 0  
One year ago (Gross write-offs) 41 2  
Two years ago (Gross write-offs) 544 360  
Three years ago (Gross write-offs) 470 457  
Four years ago (Gross write-offs) 268 20  
Prior (Gross write-offs) 827 16  
Total financing receivables 620,798   628,158
Total financing receivables (Gross write-offs) 2,150 ¥ 855  
Net investment in leases | Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 255,508   490,025
One year ago 391,826   327,849
Two years ago 262,215   202,407
Three years ago 148,535   96,189
Four years ago 68,316   47,874
Prior 71,672   56,070
Total financing receivables 1,198,072   1,220,414
Net investment in leases | Performing | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 100,573   197,362
One year ago 170,373   152,845
Two years ago 131,575   105,743
Three years ago 86,457   66,152
Four years ago 50,782   40,753
Prior 66,011   52,159
Total financing receivables 605,771   615,014
Net investment in leases | Performing | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 154,935   292,663
One year ago 221,453   175,004
Two years ago 130,640   96,664
Three years ago 62,078   30,037
Four years ago 17,534   7,121
Prior 5,661   3,911
Total financing receivables 592,301   605,400
Net investment in leases | Non-Performing      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 4,085   3,616
One year ago 6,252   5,892
Two years ago 6,436   6,810
Three years ago 6,877   3,699
Four years ago 3,774   1,456
Prior 5,343   5,604
Total financing receivables 32,767   27,077
Net investment in leases | Non-Performing | Japan      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 46   146
One year ago 280   517
Two years ago 644   865
Three years ago 792   778
Four years ago 728   668
Prior 1,780   1,345
Total financing receivables 4,270   4,319
Net investment in leases | Non-Performing | Overseas      
Financing Receivable, Recorded Investment [Line Items]      
Current fiscal year 4,039   3,470
One year ago 5,972   5,375
Two years ago 5,792   5,945
Three years ago 6,085   2,921
Four years ago 3,046   788
Prior 3,563   4,259
Total financing receivables ¥ 28,497   ¥ 22,758