v3.26.1
Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Origination Years of Financial Assets (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) ¥ 499 ¥ 271
One year ago (Gross write-offs) 1,528 2,410
Two years ago (Gross write-offs) 3,198 2,293
Three years ago (Gross write-offs) 2,789 3,225
Four years ago (Gross write-offs) 687 640
Prior (Gross write-offs) 9,864 10,189
Total financing receivables 5,212,483 5,056,614
Total financing receivables (Gross write-offs) 18,565 19,028
Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 1,699,069 1,673,007
One year ago 1,069,922 829,285
Two years ago 504,326 474,623
Three years ago 314,302 388,324
Four years ago 285,095 319,263
Prior 1,176,356 1,211,160
Total financing receivables 5,049,070 4,895,662
Non-Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 5,343 5,356
One year ago 12,541 15,789
Two years ago 18,829 12,347
Three years ago 16,432 37,016
Four years ago 16,675 9,097
Prior 43,032 34,862
Total financing receivables 112,852 114,467
Consumer borrowers    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 137 206
One year ago (Gross write-offs) 1,046 1,773
Two years ago (Gross write-offs) 1,390 1,136
Three years ago (Gross write-offs) 1,156 106
Four years ago (Gross write-offs) 128 8
Prior (Gross write-offs) 195 70
Total financing receivables 2,133,067 2,067,900
Total financing receivables (Gross write-offs) 4,052 3,299
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) 34 0
Four years ago (Gross write-offs) 105 0
Prior (Gross write-offs) 193 62
Total financing receivables 2,027,493 1,956,816
Total financing receivables (Gross write-offs) 332 62
Consumer borrowers | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 137 206
One year ago (Gross write-offs) 1,046 1,773
Two years ago (Gross write-offs) 1,390 1,136
Three years ago (Gross write-offs) 1,122 106
Four years ago (Gross write-offs) 23 8
Prior (Gross write-offs) 2 8
Total financing receivables 40,974 43,210
Total financing receivables (Gross write-offs) 3,720 3,237
Consumer borrowers | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 392,074 358,952
One year ago 290,820 154,694
Two years ago 136,404 159,847
Three years ago 137,394 143,281
Four years ago 130,105 227,594
Prior 958,672 936,220
Total financing receivables 2,045,469 1,980,588
Consumer borrowers | Performing | Real estate loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 371,586 339,308
One year ago 279,725 142,337
Two years ago 130,960 152,451
Three years ago 134,882 142,224
Four years ago 129,906 227,484
Prior 958,622 935,996
Total financing receivables 2,005,681 1,939,800
Consumer borrowers | Performing | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 20,488 19,644
One year ago 11,095 12,357
Two years ago 5,444 7,396
Three years ago 2,512 1,057
Four years ago 199 110
Prior 50 224
Total financing receivables 39,788 40,788
Consumer borrowers | Non-Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 451 586
One year ago 3,465 1,421
Two years ago 2,184 3,101
Three years ago 5,041 2,086
Four years ago 1,405 668
Prior 10,452 11,576
Total financing receivables 22,998 19,438
Consumer borrowers | Non-Performing | Real estate loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 195 224
One year ago 3,063 472
Two years ago 1,888 2,110
Three years ago 4,817 2,057
Four years ago 1,401 666
Prior 10,448 11,487
Total financing receivables 21,812 17,016
Consumer borrowers | Non-Performing | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 256 362
One year ago 402 949
Two years ago 296 991
Three years ago 224 29
Four years ago 4 2
Prior 4 89
Total financing receivables 1,186 2,422
Corporate borrowers    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 305 65
One year ago (Gross write-offs) 76 181
Two years ago (Gross write-offs) 471 73
Three years ago (Gross write-offs) 74 2,485
Four years ago (Gross write-offs) 143 24
Prior (Gross write-offs) 3,304 1,594
Total financing receivables 1,810,689 1,689,281
Total financing receivables (Gross write-offs) 4,373 4,422
Corporate borrowers | Non-recourse Loans | Japan    
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) 0 0
Total financing receivables 343,121 301,477
Total financing receivables (Gross write-offs) 0 0
Corporate borrowers | Non-recourse Loans | The Americas    
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)   150
Total financing receivables   86,724
Total financing receivables (Gross write-offs)   150
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) 1,264  
Total financing receivables 200,308  
Total financing receivables (Gross write-offs) 1,264  
Corporate borrowers | Real estate companies | Other than non-recourse loans | Japan    
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) 5 0
Four years ago (Gross write-offs) 0 0
Prior (Gross write-offs) 13 78
Total financing receivables 461,006 415,666
Total financing receivables (Gross write-offs) 18 78
Corporate borrowers | Real estate companies | Other than non-recourse loans | Overseas    
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) 0 0
Total financing receivables 61,853 82,187
Total financing receivables (Gross write-offs) 0 0
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 0
One year ago (Gross write-offs) 0 0
Two years ago (Gross write-offs) 8 0
Three years ago (Gross write-offs) 7 0
Four years ago (Gross write-offs) 0 6
Prior (Gross write-offs) 9 140
Total financing receivables 218,910 225,900
Total financing receivables (Gross write-offs) 24 146
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) 305 65
One year ago (Gross write-offs) 76 181
Two years ago (Gross write-offs) 463 73
Three years ago (Gross write-offs) 62 2,485
Four years ago (Gross write-offs) 143 18
Prior (Gross write-offs) 2,018 1,226
Total financing receivables 525,491 577,327
Total financing receivables (Gross write-offs) 3,067 4,048
Corporate borrowers | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 813,938 865,495
One year ago 449,888 246,134
Two years ago 164,930 133,623
Three years ago 78,714 154,928
Four years ago 107,095 42,744
Prior 133,575 175,757
Total financing receivables 1,748,140 1,618,681
Corporate borrowers | Performing | Non-recourse Loans | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 181,856 225,394
One year ago 113,115 52,292
Two years ago 30,906 10,487
Three years ago 7,633 6,932
Four years ago 6,753 0
Prior 2,858 6,372
Total financing receivables 343,121 301,477
Corporate borrowers | Performing | Non-recourse Loans | The Americas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year   44,762
One year ago   20,079
Two years ago   7,540
Three years ago   886
Four years ago   135
Prior   9,491
Total financing receivables   82,893
Corporate borrowers | Performing | Non-recourse Loans | Overseas    
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 | Real estate companies | Other than non-recourse loans | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 211,938 205,004
One year ago 96,971 67,092
Two years ago 40,453 33,558
Three years ago 22,320 23,295
Four years ago 19,139 19,072
Prior 69,631 67,088
Total financing receivables 460,452 415,109
Corporate borrowers | Performing | Real estate companies | Other than non-recourse loans | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 46,394 57,678
One year ago 5,163 2,458
Two years ago 1,147 8,833
Three years ago 1,120 2,828
Four years ago 0 504
Prior 5,848 6,469
Total financing receivables 59,672 78,770
Corporate borrowers | Performing | Commercial, industrial and other companies | Other than non-recourse loans | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 111,912 131,439
One year ago 52,689 38,390
Two years ago 28,678 20,382
Three years ago 8,018 10,761
Four years ago 8,374 6,412
Prior 8,501 17,740
Total financing receivables 218,172 225,124
Corporate borrowers | Performing | Commercial, industrial and other companies | Other than non-recourse loans | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 172,177 201,218
One year ago 120,405 65,823
Two years ago 40,524 52,823
Three years ago 32,225 110,226
Four years ago 70,792 16,621
Prior 42,298 68,597
Total financing receivables 478,421 515,308
Corporate borrowers | Non-Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 1,276 2,389
One year ago 3,184 8,970
Two years ago 9,835 4,353
Three years ago 7,692 33,020
Four years ago 13,814 7,593
Prior 26,748 14,275
Total financing receivables 62,549 70,600
Corporate borrowers | Non-Performing | Non-recourse Loans | The Americas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year   0
One year ago   0
Two years ago   67
Three years ago   0
Four years ago   0
Prior   3,764
Total financing receivables   3,831
Corporate borrowers | Non-Performing | Non-recourse Loans | Overseas    
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 | Real estate companies | Other than non-recourse loans | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 0 0
One year ago 19 0
Two years ago 0 0
Three years ago 0 0
Four years ago 0 8
Prior 535 549
Total financing receivables 554 557
Corporate borrowers | Non-Performing | Real estate companies | Other than non-recourse loans | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 0 104
One year ago 0 680
Two years ago 440 1,283
Three years ago 1,586 1,188
Four years ago 63 0
Prior 92 162
Total financing receivables 2,181 3,417
Corporate borrowers | Non-Performing | Commercial, industrial and other companies | Other than non-recourse loans | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 14 415
One year ago 411 58
Two years ago 47 130
Three years ago 116 11
Four years ago 11 76
Prior 139 86
Total financing receivables 738 776
Corporate borrowers | Non-Performing | Commercial, industrial and other companies | Other than non-recourse loans | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 1,262 1,870
One year ago 2,675 8,232
Two years ago 4,692 2,873
Three years ago 5,135 31,821
Four years ago 12,675 7,509
Prior 20,631 9,714
Total financing receivables 47,070 62,019
Loans to Equity Method Investees    
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 55
Three years ago (Gross write-offs) 0 39
Four years ago (Gross write-offs) 0 0
Prior (Gross write-offs) 1,439 161
Total financing receivables 21,236 132,053
Total financing receivables (Gross write-offs) 1,439 255
Loans to Equity Method Investees | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 3,032 515
One year ago 573 111,724
Two years ago 585 2,028
Three years ago 2,005 0
Four years ago 21 1,583
Prior 15,020 14,858
Total financing receivables 21,236 130,708
Loans to Equity Method Investees | 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 0 1,345
Total financing receivables 0 1,345
Purchased loans    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 0 0
One year ago (Gross write-offs) 10 0
Two years ago (Gross write-offs) 0 0
Three years ago (Gross write-offs) 0 57
Four years ago (Gross write-offs) 0 255
Prior (Gross write-offs) 3,753 7,235
Total financing receivables (Gross write-offs) 3,763 7,547
Purchased loans | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 0 0
One year ago 792 52
Two years ago 0 14
Three years ago 0 476
Four years ago 0 86
Prior 13,019 19,497
Total financing receivables 13,811 20,125
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 31
Four years ago 0 0
Prior 228 1,233
Total financing receivables 228 1,264
Net investment in leases    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 57 0
One year ago (Gross write-offs) 396 456
Two years ago (Gross write-offs) 1,337 1,029
Three years ago (Gross write-offs) 1,559 538
Four years ago (Gross write-offs) 416 353
Prior (Gross write-offs) 1,173 1,129
Total financing receivables 1,247,491 1,167,380
Total financing receivables (Gross write-offs) 4,938 3,505
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) 16 34
Two years ago (Gross write-offs) 120 135
Three years ago (Gross write-offs) 223 254
Four years ago (Gross write-offs) 189 256
Prior (Gross write-offs) 586 627
Total financing receivables 619,333 618,963
Total financing receivables (Gross write-offs) 1,134 1,306
Net investment in leases | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year (Gross write-offs) 57 0
One year ago (Gross write-offs) 380 422
Two years ago (Gross write-offs) 1,217 894
Three years ago (Gross write-offs) 1,336 284
Four years ago (Gross write-offs) 227 97
Prior (Gross write-offs) 587 502
Total financing receivables 628,158 548,417
Total financing receivables (Gross write-offs) 3,804 2,199
Net investment in leases | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 490,025 448,045
One year ago 327,849 316,681
Two years ago 202,407 179,111
Three years ago 96,189 89,639
Four years ago 47,874 47,256
Prior 56,070 64,828
Total financing receivables 1,220,414 1,145,560
Net investment in leases | Performing | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 197,362 199,069
One year ago 152,845 145,491
Two years ago 105,743 101,351
Three years ago 66,152 67,720
Four years ago 40,753 40,680
Prior 52,159 60,287
Total financing receivables 615,014 614,598
Net investment in leases | Performing | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 292,663 248,976
One year ago 175,004 171,190
Two years ago 96,664 77,760
Three years ago 30,037 21,919
Four years ago 7,121 6,576
Prior 3,911 4,541
Total financing receivables 605,400 530,962
Net investment in leases | Non-Performing    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 3,616 2,381
One year ago 5,892 5,398
Two years ago 6,810 4,893
Three years ago 3,699 1,879
Four years ago 1,456 836
Prior 5,604 6,433
Total financing receivables 27,077 21,820
Net investment in leases | Non-Performing | Japan    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 146 160
One year ago 517 628
Two years ago 865 763
Three years ago 778 808
Four years ago 668 500
Prior 1,345 1,506
Total financing receivables 4,319 4,365
Net investment in leases | Non-Performing | Overseas    
Financing Receivable, Recorded Investment [Line Items]    
Current fiscal year 3,470 2,221
One year ago 5,375 4,770
Two years ago 5,945 4,130
Three years ago 2,921 1,071
Four years ago 788 336
Prior 4,259 4,927
Total financing receivables ¥ 22,758 ¥ 17,455