v3.26.3
Fees and Expenses - Prospectus Summary - Franklin Institutional U.S. Government Money Market Fund
Jun. 30, 2026
Prospectus [Line Items]  
Expense Heading [Optional Text] Fees and Expenses of the Fund
Expense Narrative [Text Block]

These tables describe the fees and expenses that you may pay if you buy, hold and sell shares of the Fund.
Shareholder Fees Caption [Optional Text] Shareholder Fees
Shareholder Fees [Table]
Shareholder Fees
Class A
Prospectus Summary | Franklin Institutional U.S. Government Money Market Fund | Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
Annual Fund Operating Expenses - Prospectus Summary - Franklin Institutional U.S. Government Money Market Fund
Class A
Management Fees (as a percentage of Assets) 0.15%
Distribution and Service (12b-1) Fees 0.00%
Other Expenses (as a percentage of Assets): 0.20%
Expenses (as a percentage of Assets) 0.35% [1]
Fee Waiver or Reimbursement (0.18%) [2]
Net Expenses (as a percentage of Assets) 0.17% [1]
Fee Waiver or Reimbursement over Assets, Date of Termination October 31, 2027
[1] The fees and expenses shown in the table and included in the example below reflect the fees and expenses of both the Fund and The U.S. Government Money Market Portfolio (Master Portfolio), in which the Fund seeks to invest all of its assets in order to pursue its investment goal.
[2] The investment manager has agreed to waive fees and/or reimburse operating expenses (excluding acquired fund fees and expenses, interest and certain non-routine expenses or costs, such as those relating to litigation, indemnification, reorganizations and liquidations) for the Fund so that the ratio of total annual fund operating expenses will not exceed 0.17% until October 31, 2027. During the term, the fee waiver and expense reimbursement agreement may not be terminated or amended without approval of the board of trustees except to add series or classes, to reflect the extension of the termination date or to lower the waiver and expense limitation (which would result in lower fees for shareholders).
Expense Example [Heading] Example
Expense Example Narrative [Text Block]

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects adjustments made to the Fund's operating expenses due to the fee waivers and/or expense reimbursements by management

for the 1 Year numbers only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, With Redemption [Table]
Expense Example - Prospectus Summary - Franklin Institutional U.S. Government Money Market Fund
Class A
USD ($)
Expense Example, with Redemption, 1 Year $ 17
Expense Example, with Redemption, 3 Years 94
Expense Example, with Redemption, 5 Years 178
Expense Example, with Redemption, 10 Years $ 425
Expense Heading [Optional Text] Fees and Expenses of the Fund
Expense Narrative [Text Block]

These tables describe the fees and expenses that you may pay if you buy, hold and sell shares of the Fund.
Shareholder Fees Caption [Optional Text] Shareholder Fees
Shareholder Fees [Table]
Shareholder Fees
Class A
Prospectus Summary | Franklin Institutional U.S. Government Money Market Fund | Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Operating Expenses Caption [Optional Text] Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses [Table]
Annual Fund Operating Expenses - Prospectus Summary - Franklin Institutional U.S. Government Money Market Fund
Class A
Management Fees (as a percentage of Assets) 0.15%
Distribution and Service (12b-1) Fees 0.00%
Other Expenses (as a percentage of Assets): 0.20%
Expenses (as a percentage of Assets) 0.35% [1]
Fee Waiver or Reimbursement (0.18%) [2]
Net Expenses (as a percentage of Assets) 0.17% [1]
Fee Waiver or Reimbursement over Assets, Date of Termination October 31, 2027
[1] The fees and expenses shown in the table and included in the example below reflect the fees and expenses of both the Fund and The U.S. Government Money Market Portfolio (Master Portfolio), in which the Fund seeks to invest all of its assets in order to pursue its investment goal.
[2] The investment manager has agreed to waive fees and/or reimburse operating expenses (excluding acquired fund fees and expenses, interest and certain non-routine expenses or costs, such as those relating to litigation, indemnification, reorganizations and liquidations) for the Fund so that the ratio of total annual fund operating expenses will not exceed 0.17% until October 31, 2027. During the term, the fee waiver and expense reimbursement agreement may not be terminated or amended without approval of the board of trustees except to add series or classes, to reflect the extension of the termination date or to lower the waiver and expense limitation (which would result in lower fees for shareholders).
Expense Example [Heading] Example
Expense Example Narrative [Text Block]

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects adjustments made to the Fund's operating expenses due to the fee waivers and/or expense reimbursements by management

for the 1 Year numbers only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, With Redemption [Table]
Expense Example - Prospectus Summary - Franklin Institutional U.S. Government Money Market Fund
Class A
USD ($)
Expense Example, with Redemption, 1 Year $ 17
Expense Example, with Redemption, 3 Years 94
Expense Example, with Redemption, 5 Years 178
Expense Example, with Redemption, 10 Years $ 425