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 those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. The calculation of costs takes into account any applicable contractual fee waivers and/or expense reimbursements for the period noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

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The Fund will invest at least 99.5% of its total assets in cash, government securities, and/or repurchase agreements that are collateralized fully by cash or government securities (government securities can include shares of other government money market funds). The Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in government securities and repurchase agreements that are collateralized by government securities. Specifically, the Fund will invest in U.S. treasury bills, bonds, and other obligations issued or guaranteed by the U.S. government or its agencies or instrumentalities (which will include instruments with variable or floating interest rates), as well as shares of other government money market funds. The Fund seeks to maintain a stable net asset value of $1.00 per share. The Fund maintains a dollar weighted average portfolio maturity of 60 days or less. As with all mutual funds, the value of the Fund's assets may rise or fall.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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You could lose money by investing in the Fund. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund’s sponsor has no legal obligation to provide financial support to the Fund, and you should not expect that the sponsor will provide financial support to the Fund at any time. The principal risks of investing in the Fund, in alphabetical order, are:

Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.

Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate risk and credit quality risk. The market value of fixed-income securities generally declines when interest rates rise, and an issuer of fixed-income securities could default on its payment obligations.

Floating and Variable Rate Securities Risk. The market prices of securities with variable and floating interest rates are generally less sensitive to interest rate changes than are the market prices of securities of fixed interest rates. Floating and variable rate securities may decline in value if market interest rates or interest rates paid by them do not move as expected. Floating and variable rate securities may be subject to greater liquidity risk than other debt securities, meaning that there may be limitations on the Fund’s ability to sell the securities at any given time.

Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.

Repurchase Agreement Risk. If the other party to a repurchase agreement defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.

U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities.

U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored or -chartered enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. Treasury.

Risk Money Market Fund [Text]

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You could lose money by investing in the Fund.

Risk Not Insured Depository Institution [Text]

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An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

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No performance information is shown below because the Fund has not yet had a calendar year of performance. The

Fund's performance is benchmarked against the Bloomberg Barclays U.S. Treasury Bellwethers 3 Month Index. Performance information provides some indication of the risks of investing in the Fund. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You may get updated performance information, including the 7-day yield, by calling 1-800-222-5852.

Performance One Year or Less [Text]

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No performance information is shown below because the Fund has not yet had a calendar year of performance.

Performance Additional Market Index [Text]

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TheFund's performance is benchmarked against the Bloomberg Barclays U.S. Treasury Bellwethers 3 Month Index.

Performance Availability Phone [Text]

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1-800-222-5852

Performance Availability Website Address [Text]

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www.principal.com

Performance Past Does Not Indicate Future [Text]

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Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

PFI Prospectus | Government Money Market Fund | Government Money Market Fund Institutional

Prospectus:

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Trading Symbol

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PGVXX

Shareholder Fee, Other

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none

Management Fees (as a percentage of Assets)

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0.15%

Other Expenses (as a percentage of Assets):

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0.02%

^[1]

Acquired Fund Fees and Expenses

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0.01%

^[1]

Expenses (as a percentage of Assets)

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0.18%

Fee Waiver or Reimbursement

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(0.03%)

^[2],[3]

Net Expenses (as a percentage of Assets)

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0.15%

Expense Example, with Redemption, 1 Year

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$ 15

Expense Example, with Redemption, 3 Years

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$ 52

[1]	Based on estimated amounts for the current fiscal year.
[2]	Principal Global Investors, LLC ("PGI"), the investment advisor, has contractually agreed to limit the Fund's expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain a total level of operating expenses (expressed as a percent of average net assets on an annualized basis) not to exceed 0.15% for Institutional Class Shares. It is expected that the expense limit will continue through the period ending February 29, 2020; however, Principal Funds, Inc. and PGI, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.
[3]	Principal Global Investors, LLC ("PGI"), the investment advisor, has contractually agreed to reduce the Fund's Management Fees through the period ending February 29, 2020. The fee waiver will reduce the Fund's Management Fees in an amount equal to all Acquired Fund Fees and Expenses. It is expected that the fee waiver will continue through the period disclosed; however, Principal Funds, Inc. and PGI, the parties to the agreement, may mutually agree to terminate the fee waiver prior to the end of the period.