Shareholder Report, Holdings (Details) - Fidelity Government Cash Reserves |
May 31, 2026 |
|---|---|
| EMD0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 61.10% |
| EMD1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.50% |
| EMD2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.80% |
| EMD3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.50% |
| EMD4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.50% |
| EMD5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.70% |
| AARepurchaseAgreementsMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 41.60% |
| AAUSTreasuryObligationsMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 30.90% |
| AAUSGovernmentAgencyDebtMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 29.90% |