Shareholder Report |
12 Months Ended | |||||||||
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Apr. 30, 2026
USD ($)
Holding
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| Shareholder Report [Line Items] | ||||||||||
| Document Type | N-CSR | |||||||||
| Amendment Flag | false | |||||||||
| Registrant Name | BlackRock Funds | |||||||||
| Entity Central Index Key | 0000844779 | |||||||||
| Entity Investment Company Type | N-1A | |||||||||
| Document Period End Date | Apr. 30, 2026 | |||||||||
| C000237396 [Member] | ||||||||||
| Shareholder Report [Line Items] | ||||||||||
| Fund Name | Circle Reserve Fund | |||||||||
| Class Name | Institutional Shares | |||||||||
| Trading Symbol | USDXX | |||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Circle Reserve Fund (the “Fund”) for the period of May 1, 2025 to April 30, 2026. | |||||||||
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |||||||||
| Additional Information [Text Block] | You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7450. | |||||||||
| Additional Information Phone Number | (800) 441‑7450 | |||||||||
| Additional Information Website | blackrock.com/fundreports | |||||||||
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
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| Expenses Paid, Amount | $ 9 | |||||||||
| Expense Ratio, Percent | 0.09% | |||||||||
| Performance Past Does Not Indicate Future [Text] | Past performance is not an indication of future results. | |||||||||
| Updated Performance Information Location [Text Block] | Visit blackrock.com for more recent yield information. | |||||||||
| Net Assets | $ 66,367,042,789 | |||||||||
| Holdings Count | Holding | 29 | |||||||||
| Advisory Fees Paid, Amount | $ 30,854,444 | |||||||||
| Additional Fund Statistics [Text Block] | Key Fund statistics
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| Holdings [Text Block] | What did the Fund invest in? (as of April 30, 2026) Portfolio composition
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