| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BERKSHIRE FUNDS |
| Entity Central Index Key | 0001030979 |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BERKSHIRE FUNDS |
| Entity Central Index Key | 0001030979 |
| Document Period End Date | Jun. 30, 2024 |
| Berkshire Focus Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | BERKSHIRE FOCUS FUND |
| Class Name | Berkshire Focus Fund |
| Trading Symbol | BFOCX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the fund at www.berkshirefunds.com. 1-877-526-0707 |
| Additional Information Phone Number | 1-877-526-0707 |
| Additional Information Website | www.berkshirefunds.com. |
| Expenses [Text Block] | Fund Costs (based on hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Berkshire Focus Fund $112.14 1.97% |
| Expenses Paid, Amount | $ 112.14 |
| Expense Ratio, Percent | 1.97% |
| Factors Affecting Performance [Text Block] | Management’s Discussion of Performance For the six-month period ended June 30, 2024, the Berkshire Focus Fund outperformed its primary benchmark index. The Fund generated a total return of 28.95% while the S&P 500 ® ® U.S. equity markets extended their upward climb in the first half of 2024. The S&P 500 ® Our investments in NVIDIA (NVDA), Broadcom (AVGO), Meta Platforms (META), and Eli Lilly (LLY) were contributors to the Fund’s performance. However, some of our investments detracted from the Fund’s performance—these included DoorDash (DASH), DraftKings (DKNG), Block (SQ) and Tesla (TSLA). New significant additions to the portfolio in the first half were Apple (AAPL), Arista Networks (ANET), Microsoft (MSFT), Palantir (PLTR), and Taiwan Semiconductor (TSM). |
| Line Graph [Table Text Block] | |
| Net Assets | $ 246,800,000 |
| Holdings Count | Holding | 22 |
| Advisory Fees Paid, Amount | $ 1,763,012 |
| Investment Company, Portfolio Turnover | 1,197.10% |
| Additional Fund Statistics [Text Block] | Fund Statistics Net Assets: $ 246.8 Portfolio Holdings: 22 Portfolio Turnover: 1197.1% Total Advisory Fees Paid: $ 1,763,012 |
| Updated Prospectus Web Address | www.berkshirefunds.com. |
| Shareholder Report, Line Graph (Details) - USD ($) | Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2014 | |
| Berkshire Focus Fund | ||||||||||||
| Account Value [Line Items] | ||||||||||||
| Account Value | [1] | $ 30,796 | $ 23,000 | $ 20,000 | $ 45,000 | $ 30,000 | $ 22,000 | $ 19,500 | $ 12,000 | $ 9,500 | $ 10,000 | $ 9,500 |
| S&P 500® Index | ||||||||||||
| Account Value [Line Items] | ||||||||||||
| Account Value | [1] | $ 33,521 | $ 27,150 | $ 22,200 | $ 25,500 | $ 18,000 | $ 16,000 | $ 14,000 | $ 12,300 | $ 10,100 | $ 10,000 | $ 9,400 |
| [1]The Fund’s past performance is not a good predictor of the Fund’s future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. | ||||||||||||
| Shareholder Report, Average Annual Return (Details) | 12 Months Ended | 60 Months Ended | 120 Months Ended | |
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | ||
| Berkshire Focus Fund | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | [1] | 34.62% | 6.49% | 11.90% |
| S&P 500® Index | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | [1] | 24.56% | 15.05% | 12.86% |
| [1]The Fund’s past performance is not a good predictor of the Fund’s future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. | ||||
| Shareholder Report, Holdings (Details) - Berkshire Focus Fund | Jun. 30, 2024 |
| NVIDIA Corp. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 10.92% |
| Amazon.com, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.02% |
| Broadcom, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.15% |
| Arista Networks, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.08% |
| Eli Lilly and Company | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.05% |
| Taiwan Semiconductor Mfg. Co. Ltd. – ADR | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.05% |
| Cloudflare, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.03% |
| The Trade Desk, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.98% |
| Apple, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.92% |
| Meta Platforms, Inc. | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.92% |
| Semiconductors | |
| Holdings [Line Items] | |
| Percent of Total Investments | 29.18% |
| Business Software & Services | |
| Holdings [Line Items] | |
| Percent of Total Investments | 18.48% |
| Communication Equipment | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.60% |
| Computer Hardware | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.99% |
| Internet Services | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.03% |
| Drug Manufacturers | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.05% |
| Semiconductor Equipment | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.92% |
| Consumer Electronics | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.92% |
| Internet Social Media | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.92% |
| Cybersecurity Equipment & Services | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.05% |
| Automobile Manufacturers | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.02% |
| Hotels, Restaurants & Leisure | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.03% |
| Cryptocurrency | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.01% |
