v3.26.1
Loans - Credit Quality Information of Loans Based on MHFG Group's Internal Rating System (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Normal obligors | Domestic | Retail | Housing Loan    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 [1] ¥ 508 ¥ 342,000
2024 [1] 279 289,000
2023 [1] 273 370,000
2022 [1] 348 405,000
2021 [1] 381 320,000
Prior to 2021 [1] 4,784 5,026,000
Total [1] 6,573 6,753,000
Normal obligors | Domestic | Retail | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 [1] 202 149,000
2024 [1] 59 105,000
2023 [1] 74 54,000
2022 [1] 35 38,000
2021 [1] 24 77,000
Prior to 2021 [1] 269 306,000
Revolving Loans [1],[2] 445 449,000
Total [1] 1,109 1,179,000
Watch obligors | Domestic | Retail | Housing Loan    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2021 [1]   1,000
Prior to 2021 [1] 28 37,000
Total [1] 29 39,000
Watch obligors | Domestic | Retail | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 [1] 14 15,000
2024 [1] 5 10,000
2023 [1] 6 5,000
2022 [1] 3 3,000
2021 [1] 2 8,000
Prior to 2021 [1] 8 6,000
Revolving Loans [1],[2] 7 7,000
Total [1] 45 53,000
Non Accrual Loans | Domestic | Retail | Housing Loan    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 [1] 1  
2021 [1]   1,000
Prior to 2021 [1] 27 29,000
Total [1] 28 30,000
Non Accrual Loans | Domestic | Retail | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 [1] 5 4,000
2024 [1] 2 3,000
2023 [1] 3 1,000
2022 [1] 2 2,000
2021 [1] 2 5,000
Prior to 2021 [1] 20 19,000
Revolving Loans [1],[2] 7 8,000
Total [1] 41 43,000
Financing Receivables Not Impaired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 37,395 34,872,000
2024 14,137 12,502,000
2023 8,960 9,205,000
2022 6,250 5,801,000
2021 4,134 4,850,000
Prior to 2021 13,407 13,553,000
Revolving Loans [2] 21,553 18,475,000
Total 105,836 99,257,000
Financing Receivables Not Impaired | Domestic    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 18,872 19,091,000
2024 8,088 6,857,000
2023 5,456 5,322,000
2022 4,171 4,390,000
2021 3,267 4,122,000
Prior to 2021 12,020 11,979,000
Revolving Loans [2] 10,868 9,521,000
Total 62,742 61,282,000
Financing Receivables Not Impaired | Foreign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 18,523 15,781,000
2024 6,049 5,645,000
2023 3,504 3,883,000
2022 2,079 1,411,000
2021 867 728,000
Prior to 2021 1,387 1,574,000
Revolving Loans [2] 10,685 8,954,000
Total 43,094 37,975,000
Financing Receivables Not Impaired | Normal obligors | Domestic | Soverign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 128 3,212,000
2024 41 55,000
2023 46 47,000
2022 47 44,000
2021 46 86,000
Prior to 2021 237 239,000
Revolving Loans [2] 3 4,000
Total 548 3,687,000
Financing Receivables Not Impaired | Normal obligors | Domestic | Banks and other financial institutions    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 257 160,000
2024 80 81,000
2023 76 71,000
2022 9 252,000
2021 252 1,000
Prior to 2021 21 80,000
Revolving Loans [2] 315 221,000
Total 1,009 867,000
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Large Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 16,827 14,418,000
2024 7,098 5,880,000
2023 4,561 4,464,000
2022 3,462 3,358,000
2021 2,377 3,391,000
Prior to 2021 5,846 5,256,000
Revolving Loans [2] 8,981 7,775,000
Total 49,151 44,542,000
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Small And Medium Sized Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 534 489,000
2024 295 313,000
2023 229 236,000
2022 173 164,000
2021 124 146,000
Prior to 2021 569 621,000
Revolving Loans [2] 546 536,000
Total 2,472 2,506,000
Financing Receivables Not Impaired | Normal obligors | Foreign | Soverign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 558 318,000
2024 98 220,000
2023 119 194,000
2022 58 7,000
2021 4 2,000
Prior to 2021 8 3,000
Revolving Loans [2] 100 35,000
Total 945 778,000
Financing Receivables Not Impaired | Normal obligors | Foreign | Banks and other financial institutions    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 1,701 1,333,000
2024 643 631,000
2023 354 485,000
2022 146 112,000
2021 10 27,000
Prior to 2021 193 193,000
Revolving Loans [2] 533 454,000
Total 3,579 3,235,000
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 15,947 [3] 13,891,000 [4]
2024 5,187 [3] 4,670,000 [4]
2023 2,892 [3] 3,086,000 [4]
2022 1,826 [3] 1,254,000 [4]
2021 823 [3] 580,000 [4]
Prior to 2021 1,087 [3] 1,268,000 [4]
Revolving Loans [2] 9,884 [3] 8,360,000 [4]
Total 37,646 [3] 33,108,000 [4]
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 3 2,000
2024 1 1,000
2023 1 1,000
2022 1 1,000
2021 1 1,000
Prior to 2021 4 4,000
Total 13 10,000
Financing Receivables Not Impaired | Watch obligors | Domestic | Soverign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 2 2,000
2024   2,000
2023 2 1,000
Total 4 5,000
Financing Receivables Not Impaired | Watch obligors | Domestic | Banks and other financial institutions    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revolving Loans [2] 56  
Total 56  
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Large Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 226 153,000
2024 149 47,000
2023 128 29,000
2022 57 76,000
2021 33 21,000
Prior to 2021 72 49,000
Revolving Loans [2] 197 162,000
Total 864 537,000
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Small And Medium Sized Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 55 41,000
2024 20 18,000
2023 14 12,000
2022 10 9,000
2021 8 7,000
Prior to 2021 35 37,000
Revolving Loans [2] 28 24,000
Total 170 148,000
Financing Receivables Not Impaired | Watch obligors | Foreign | Soverign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2024   3,000
Total   3,000
Financing Receivables Not Impaired | Watch obligors | Foreign | Banks and other financial institutions    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2023   4,000
Prior to 2021 8 11,000
Revolving Loans [2] 2  
Total 11 16,000
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 278 [3] 220,000 [4]
2024 99 [3] 96,000 [4]
2023 109 [3] 95,000 [4]
2022 47 [3] 36,000 [4]
2021 16 [3] 113,000 [4]
Prior to 2021 67 [3] 76,000 [4]
Revolving Loans [2] 97 [3] 95,000 [4]
Total 714 [3] 730,000 [4]
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Corporate | Large Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 103 97,000
2024 54 49,000
2023 39 27,000
2022 20 31,000
2021 13 46,000
Prior to 2021 70 239,000
Revolving Loans [2] 259 309,000
Total 558 800,000
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Corporate | Small And Medium Sized Companies    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 9 8,000
2024 5 5,000
2023 5 6,000
2022 5 5,000
2021 3 10,000
Prior to 2021 34 34,000
Revolving Loans [2] 24 24,000
Total 86 92,000
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Soverign    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025   0
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Corporate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
2025 36 [3] 17,000 [4]
2024 21 [3] 25,000 [4]
2023 28 [3] 19,000 [4]
2022 [4]   1,000
2021 14 [3] 4,000 [4]
Prior to 2021 19 [3] 19,000 [4]
Revolving Loans [2] 69 [3] 10,000 [4]
Total ¥ 187 [3] ¥ 96,000 [4]
[1] The primary component of the retail portfolio segment is housing loans to individuals which obligor category is classified based on past due status. The trigger to reclassify obligors from normal obligors to watch obligors excluding special attention obligors is when the past due status is more than 30 days.
[2] There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2025 and 2026.
[3] Corporate of foreign included ¥166 billion and ¥169 billion of lease receivables that were receivables arising from direct financing leasing at March 31, 2025 and 2026, respectively.
[4] Corporate of foreign included ¥166 billion and ¥169 billion of lease receivables that were receivables arising from direct financing leasing at March 31, 2025 and 2026, respectively.