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Label Element Value
Prospectus: rr_ProspectusTable  
Document Type dei_DocumentType 497
Document Period End Date dei_DocumentPeriodEndDate Oct. 31, 2015
Entity Registrant Name dei_EntityRegistrantName PRINCIPAL FUNDS INC
Central Index Key dei_EntityCentralIndexKey 0000898745
Amendment Flag dei_AmendmentFlag false
Document Creation Date dei_DocumentCreationDate Jul. 01, 2016
Document Effective Date dei_DocumentEffectiveDate Jul. 01, 2016
Prospectus Date rr_ProspectusDate Jun. 28, 2016
PFI Prospectus | Finisterre Unconstrained Emerging Markets Bond Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading FINISTERRE UNCONSTRAINED EMERGING MARKETS BOND FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks to generate total returns from current income and capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Class A Shares of Principal Funds, Inc. More information about these and other discounts is available from your financial professional and in “Choosing a Share Class and The Costs of Investing” beginning on page 103 of the Fund’s prospectus and “Multiple Class Structure” beginning on page 6 of the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. This is a new fund and does not yet have a portfolio turnover rate to disclose.
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Class A Shares of Principal Funds, Inc.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 100,000
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment
purposes, in bonds, debt securities and other fixed-income securities, and in derivatives on such investments, that are issued by emerging market countries. A security is issued by an emerging market country if it is issued by the emerging market country’s government, is issued by a corporate entity that has its principal place of business or principal office in an emerging market country, or whose principal securities trading market is in an emerging market country. Emerging market countries include frontier market countries. The Fund actively trades portfolio securities.
The Fund follows an investment process that focuses primarily on market level analysis of global markets and political developments and their impact on individual countries and companies in emerging markets. The portfolio construction process for the Fund will follow a top-down process, blending both fundamental and technical considerations. The unconstrained nature of the investment strategy provides greater flexibility to identify opportunities across asset classes, capital structures, maturities, and currencies.
The types of fixed-income securities that the Fund can invest in include bonds, asset-backed securities (securitized products), convertible bonds, contingent convertible securities (hybrid bonds that will, when the issuers capital ratio falls below a predetermined trigger level, be converted into an equity security), credit and index linked securities, and non-registered or restricted securities (including those issued in reliance on Rule 144A and Regulation S). These types of securities may be issued by stressed, distressed and bankrupt issuers.
The Fund may invest, without limitation, in high yield securities (also known as “junk bonds”) rated at the time of purchase Ba1 or lower by Moody’s Investors Services, Inc., and BB+ or lower by Standard & Poor’s Rating Services (if the security has been rated by only one of these agencies, that rating will determine whether the security is below investment grade; if the security has not been rated by either of those agencies, the Sub-Advisor will determine whether the security is of a quality comparable to those rated below investment grade). Holdings may range in maturity from overnight to 30 years or more and will not be subject to any minimum credit rating standard. The Fund also utilizes derivatives to enhance return, hedge the value of its assets against adverse movements, and manage certain investment risks. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. Specifically, the Fund expects to use forward contracts, futures, options, and swaps.
The Fund is considered non-diversified, which means it can invest a higher percentage of assets in securities of individual issuers than a diversified fund.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The value of your investment in the Fund changes with the value of the Fund's investments. Many factors affect that value, and it is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund, in alphabetical order, are:
Convertible Securities Risk. Convertible securities are bonds, notes, debentures, preferred stock or other securities which are convertible into common stock. Convertible securities are subject to credit and interest rate risks associated with fixed income securities and to stock market risk associated with equity securities.
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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Credit Default Swaps. Credit default swap agreements involve specific risks because they may be difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). Credit default swaps can increase credit risk because the fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap.
•
Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action through exchange controls that would restrict the ability of the fund to deliver or receive currency.
•
Forward Contracts, Futures and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the forward contract, future or swap; possible lack of a liquid secondary market for a forward contract, future or swap and the resulting inability to close a forward contract, future or swap when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•
Options. Options involve specific risks, including: imperfect correlation between the change in market value of the instruments held by the fund and the price of the options, counterparty risk, difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets), and an insufficient liquid secondary market for particular options.
Distressed Investments Risk. A fund’s investment in instruments involving loans, loan participations, bonds, notes, non-performing and sub-performing mortgage loans, many of which are not publicly traded, may involve a substantial degree of risk for the following reasons. These instruments may become illiquid and the prices of such instruments may be extremely volatile. Valuing such instruments may be difficult and a fund may lose all of its investment, or it may be required to accept cash or securities with a value less than the fund’s original investment. Issuers of distressed securities are typically in a weak financial condition and may default, in which case the fund may lose its entire investment.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
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Frontier Markets Risk. Frontier market countries are emerging market countries, but generally have small economies or less mature capital markets than more developed emerging markets, and, as a result, the risks of investing in emerging market countries are magnified in frontier countries. The markets of frontier countries typically have low trading volumes and the potential for extreme price volatility and illiquidity.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Hedging Risk. A fund that implements a hedging strategy using derivatives and/or securities could expose the fund to the risk that can arise when a change in the value of a hedge does not match a change in the value of the asset it hedges. In other words, the change in value of the hedge could move in a direction that does not match the change in value of the underlying asset, resulting in a risk of loss to the fund.
High Yield Securities Risk. High yield fixed-income securities (commonly referred to as "junk bonds") are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Leverage Risk. Leverage created by borrowing or certain types of transactions or investments may impair the fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the fund’s net asset value, or diminish the fund’s performance.
Non-Diversification Risk. A non-diversified fund may invest a high percentage of its assets in the securities of a small number of issuers and is more likely than diversified funds to be significantly affected by a specific security’s poor performance.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Portfolio Turnover (Active Trading) Risk. A fund that has a portfolio turnover rate over 100% is considered actively traded. Actively trading portfolio securities may accelerate realization of taxable gains and losses, lower fund performance and may result in high portfolio turnover rates and increased brokerage costs.
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Risk Lose Money [Text] rr_RiskLoseMoney The value of your investment in the Fund changes with the value of the Fund's investments. Many factors affect that value, and it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 JPM CEMBI Diversified Index. Performance information provides an 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 by calling 1-800-222-5852 or online at:
•
For Class A and P - www.principalfunds.com.
•
For Institutional Class - www.principal.com.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess No performance information is shown below because the Fund has not yet had a calendar year of performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principalfunds.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.
PFI Prospectus | Finisterre Unconstrained Emerging Markets Bond Fund | Finisterre Unconstrained Emerging Markets Bond Fund, Class A  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PFUEX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 3.75%
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice 1.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 1.02%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.60% [1]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.87%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.40%) [2]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.47%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 519
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 877
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principalfunds.com
PFI Prospectus | Finisterre Unconstrained Emerging Markets Bond Fund | Finisterre Unconstrained Emerging Markets Bond Fund, Class P  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PFUBX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 1.02%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.43% [1]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.45%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.30%) [2]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.15%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 117
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 408
PFI Prospectus | Finisterre Unconstrained Emerging Markets Bond Fund | Finisterre Unconstrained Emerging Markets Bond Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PFUMX
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage of Offering Price) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 1.02%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.43% [1]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.45%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.33%) [2]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.12%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 114
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 403
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
PFI Prospectus | Principal LifeTime Hybrid Income Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID INCOME FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks current income
Objective, Secondary [Text Block] rr_ObjectiveSecondaryTextBlock
and as a secondary objective, capital appreciation
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 116.2% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 116.20%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund invests according to an asset allocation strategy designed for investors primarily seeking current income and secondarily capital appreciation. The Fund's asset allocation is designed for investors who are approximately 15 years beyond the normal retirement age of 65. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund actively trades portfolio securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of large market capitalization companies, fixed-income securities, domestic and foreign securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, mortgage-backed securities (securitized products), and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use futures, options, swaps (including, for example, credit default, interest rate, and currency swaps) and forwards.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, 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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
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Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
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Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Portfolio Turnover (Active Trading) Risk. A fund that has a portfolio turnover rate over 100% is considered actively traded. Actively trading portfolio securities may accelerate realization of taxable gains and losses, lower fund performance and may result in high portfolio turnover rates and increased brokerage costs.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q1 '15
2.37
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(2.03
)%
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid Income Fund | S&P Target Date Retirement Income Index [Member]  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date Retirement Income Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.18%)
Since Inception rr_AverageAnnualReturnSinceInception 1.05%
PFI Prospectus | Principal LifeTime Hybrid Income Fund | Principal LifeTime Hybrid Income Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTFX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [3]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 34.60%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 35.08%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (34.55%) [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.53%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 54
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 4,165
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 7,602
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 10,340
Annual Return 2015 rr_AnnualReturn2015 (0.05%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 2.37%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (2.03%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.05%)
Since Inception rr_AverageAnnualReturnSinceInception 1.08%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid Income Fund | Principal LifeTime Hybrid Income Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.63%)
Since Inception rr_AverageAnnualReturnSinceInception (0.72%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid Income Fund | Principal LifeTime Hybrid Income Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.04%
Since Inception rr_AverageAnnualReturnSinceInception 0.13%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid Income Fund | Principal LifeTime Hybrid Income Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLTYX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [3]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 16.28% [5]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 16.76%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (16.26%) [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.50%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 51
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,301
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 5,014
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 9,451
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.05%)
Since Inception rr_AverageAnnualReturnSinceInception 1.08%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2015 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 20.9% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 20.90%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, mortgage-backed and asset-backed securities (securitized products), and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use futures, options, swaps (including, for example, credit default, interest rate, and currency swaps) and forwards.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, 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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q1 '15
2.56
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(4.12
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund | S&P Target Date 2015 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2015 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.16%)
Since Inception rr_AverageAnnualReturnSinceInception 1.34%
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund | Principal LifeTime Hybrid 2015 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTMX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [6]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 5.45%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.43%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 5.88%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (5.40%) [7]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.48%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 49
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 920
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,160
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 5,167
Annual Return 2015 rr_AnnualReturn2015 (0.47%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 2.56%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (4.12%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.47%)
Since Inception rr_AverageAnnualReturnSinceInception 1.34%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund | Principal LifeTime Hybrid 2015 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (1.01%)
Since Inception rr_AverageAnnualReturnSinceInception (0.34%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund | Principal LifeTime Hybrid 2015 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.12%)
Since Inception rr_AverageAnnualReturnSinceInception 0.52%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2015 Fund | Principal LifeTime Hybrid 2015 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLRRX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [6]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 2.65% [8]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.43%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 3.08%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (2.63%) [7]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.45%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 46
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 525
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,218
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,072
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.47%)
Since Inception rr_AverageAnnualReturnSinceInception 1.34%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2020 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 40.7% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 40.70%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use futures, options, swaps (including, for example, credit default, interest rate, and currency swaps) and forwards.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, 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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares) [9]
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q1 '15
2.86
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(4.70
)%
 [9]
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. [9]
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. [9]
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes. [9]
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
 [9]
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund | S&P Target Date 2020 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2020 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.19%)
Since Inception rr_AverageAnnualReturnSinceInception 1.41%
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund | Principal LifeTime Hybrid 2020 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [9]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 2.70%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.44%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 3.14%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (2.65%) [10]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.49%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 50
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 540
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,245
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,128
Annual Return 2015 rr_AnnualReturn2015 (0.23%) [9]
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 2.86%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (4.70%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.23%)
Since Inception rr_AverageAnnualReturnSinceInception 1.84%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund | Principal LifeTime Hybrid 2020 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.75%)
Since Inception rr_AverageAnnualReturnSinceInception 0.20%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund | Principal LifeTime Hybrid 2020 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.04%
Since Inception rr_AverageAnnualReturnSinceInception 0.96%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2020 Fund | Principal LifeTime Hybrid 2020 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLTTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [9]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.34% [11]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.44%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.78%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (1.32%) [10]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.46%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 47
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 340
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 753
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,907
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.23%)
Since Inception rr_AverageAnnualReturnSinceInception 1.84%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2025 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 89.0% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 89.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use futures, options, swaps (including, for example, credit default, interest rate, and currency swaps) and forwards.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, 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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q1 '15
3.16
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(5.27
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund | S&P Target Date 2025 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2025 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.25%)
Since Inception rr_AverageAnnualReturnSinceInception 1.31%
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund | Principal LifeTime Hybrid 2025 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTQX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [12]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 6.35%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.46%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 6.81%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (6.30%) [13]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.51%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 52
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,051
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,456
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 5,751
Annual Return 2015 rr_AnnualReturn2015 (0.18%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 3.16%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (5.27%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.18%)
Since Inception rr_AverageAnnualReturnSinceInception 2.14%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund | Principal LifeTime Hybrid 2025 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.94%)
Since Inception rr_AverageAnnualReturnSinceInception 0.32%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund | Principal LifeTime Hybrid 2025 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.10%)
Since Inception rr_AverageAnnualReturnSinceInception 1.06%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2025 Fund | Principal LifeTime Hybrid 2025 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLFTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [12]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 3.07% [14]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.46%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 3.53%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (3.05%) [13]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.48%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 49
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 593
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,380
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,449
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.08%)
Since Inception rr_AverageAnnualReturnSinceInception 2.23%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2030 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 27.3% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 27.30%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use futures, options, swaps (including, for example, credit default, interest rate, and currency swaps) and forwards.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, 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.
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
3.18
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(5.74
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund | S&P Target Date 2030 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2030 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.30%)
Since Inception rr_AverageAnnualReturnSinceInception 1.32%
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund | Principal LifeTime Hybrid 2030 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTNX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [15]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 3.60%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.45%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 4.05%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (3.55%) [16]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.50%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 51
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 670
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,561
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,864
Annual Return 2015 rr_AnnualReturn2015 (0.18%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 3.18%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (5.74%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.18%)
Since Inception rr_AverageAnnualReturnSinceInception 2.36%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund | Principal LifeTime Hybrid 2030 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.89%)
Since Inception rr_AverageAnnualReturnSinceInception 0.62%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund | Principal LifeTime Hybrid 2030 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.10%)
Since Inception rr_AverageAnnualReturnSinceInception 1.28%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2030 Fund | Principal LifeTime Hybrid 2030 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLZTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [15]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.77% [17]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.45%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 2.22%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (1.75%) [16]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.47%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 48
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 405
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 915
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 2,318
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.18%)
Since Inception rr_AverageAnnualReturnSinceInception 2.36%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2035 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 18.9% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 18.90%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, and U.S. government and U.S. government-sponsored securities. The underlying funds engage in derivative transactions to gain exposure to a variety of securities or asset classes or attempt to reduce risk. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
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 Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
3.49
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(6.21
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund | S&P Target Date 2035 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2035 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.35%)
Since Inception rr_AverageAnnualReturnSinceInception 1.33%
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund | Principal LifeTime Hybrid 2035 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTJX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [18]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 5.36%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 5.84%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (5.31%) [19]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.53%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 54
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 922
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,154
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 5,145
Annual Return 2015 rr_AnnualReturn2015 (0.19%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 3.49%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.21%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.19%)
Since Inception rr_AverageAnnualReturnSinceInception 2.49%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund | Principal LifeTime Hybrid 2035 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.66%)
Since Inception rr_AverageAnnualReturnSinceInception 0.99%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund | Principal LifeTime Hybrid 2035 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.13%
Since Inception rr_AverageAnnualReturnSinceInception 1.61%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2035 Fund | Principal LifeTime Hybrid 2035 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLRTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [18]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 2.61% [20]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 3.09%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (2.59%) [19]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.50%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 51
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 534
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,229
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,087
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.19%)
Since Inception rr_AverageAnnualReturnSinceInception 2.49%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2040 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 36.5% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 36.50%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), and derivatives. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.)currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Risk Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
3.79
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(6.50
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund | S&P Target Date 2040 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2040 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.40%)
Since Inception rr_AverageAnnualReturnSinceInception 1.30%
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund | Principal LifeTime Hybrid 2040 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLTQX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [21]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 6.93%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.44%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 7.37%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (6.88%) [22]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.49%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 50
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,123
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,624
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 6,076
Annual Return 2015 rr_AnnualReturn2015 (0.10%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 3.79%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.50%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.10%)
Since Inception rr_AverageAnnualReturnSinceInception 2.63%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund | Principal LifeTime Hybrid 2040 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.55%)
Since Inception rr_AverageAnnualReturnSinceInception 1.18%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund | Principal LifeTime Hybrid 2040 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.19%
Since Inception rr_AverageAnnualReturnSinceInception 1.77%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2040 Fund | Principal LifeTime Hybrid 2040 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLMTX
Shareholder Fee, Other rr_ShareholderFeeOther
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [21]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 3.35% [23]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.44%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 3.79%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (3.33%) [22]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.46%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 47
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 627
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,466
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 3,656
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.10%)
Since Inception rr_AverageAnnualReturnSinceInception 2.63%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2045 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 19.3% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 19.30%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), and derivatives. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Risk Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
4.02
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(6.89
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund | S&P Target Date 2045 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2045 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.46%)
Since Inception rr_AverageAnnualReturnSinceInception 1.26%
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund | Principal LifeTime Hybrid 2045 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTYX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [24]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 9.13%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 9.61%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (9.08%) [25]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.53%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 54
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,424
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 3,278
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 7,216
Annual Return 2015 rr_AnnualReturn2015 (0.40%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.02%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.89%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.40%)
Since Inception rr_AverageAnnualReturnSinceInception 2.45%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund | Principal LifeTime Hybrid 2045 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.85%)
Since Inception rr_AverageAnnualReturnSinceInception 1.04%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund | Principal LifeTime Hybrid 2045 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.03%
Since Inception rr_AverageAnnualReturnSinceInception 1.67%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2045 Fund | Principal LifeTime Hybrid 2045 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLNTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [24]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 4.39% [26]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 4.87%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (4.37%) [25]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.50%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 51
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 784
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,835
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 4,476
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.40%)
Since Inception rr_AverageAnnualReturnSinceInception 2.45%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2050 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 9.6% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 9.60%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), and derivatives. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Risk Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
4.22
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(7.07
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund | S&P Target Date 2050 Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2050 Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.47%)
Since Inception rr_AverageAnnualReturnSinceInception 1.29%
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund | Principal LifeTime Hybrid 2050 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PHTUX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [27]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 12.41%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.47%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 12.88%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (12.36%) [28]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.52%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 53
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,837
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 4,133
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 8,465
Annual Return 2015 rr_AnnualReturn2015 (0.11%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.22%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (7.07%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.11%)
Since Inception rr_AverageAnnualReturnSinceInception 2.68%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund | Principal LifeTime Hybrid 2050 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.54%)
Since Inception rr_AverageAnnualReturnSinceInception 1.31%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund | Principal LifeTime Hybrid 2050 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.21%
Since Inception rr_AverageAnnualReturnSinceInception 1.88%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2050 Fund | Principal LifeTime Hybrid 2050 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLJTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [27]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 5.93% [29]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.47%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 6.40%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (5.91%) [28]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.49%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 50
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 992
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,326
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 5,500
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.11%)
Since Inception rr_AverageAnnualReturnSinceInception 2.68%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2055 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund. During its most recent fiscal year, the Fund's portfolio turnover rate was 49.9% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 49.90%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), and derivatives. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Risk Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
4.43
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(7.35
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund | S&P Target Date 2055 Plus Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2055+ Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.54%)
Since Inception rr_AverageAnnualReturnSinceInception 1.22%
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund | Principal LifeTime Hybrid 2055 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLTNX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [30]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 45.67%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 46.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (45.62%) [31]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.53%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 54
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 5,030
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 8,224
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 9,797
Annual Return 2015 rr_AnnualReturn2015 (0.22%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.43%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (7.35%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.22%)
Since Inception rr_AverageAnnualReturnSinceInception 2.66%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund | Principal LifeTime Hybrid 2055 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.64%)
Since Inception rr_AverageAnnualReturnSinceInception 1.30%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund | Principal LifeTime Hybrid 2055 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.15%
Since Inception rr_AverageAnnualReturnSinceInception 1.88%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2055 Fund | Principal LifeTime Hybrid 2055 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLHTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [30]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 21.36% [32]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.48%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 21.84%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (21.34%) [31]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.50%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 51
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,873
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 5,973
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 10,159
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.22%)
Since Inception rr_AverageAnnualReturnSinceInception 2.66%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund  
Prospectus: rr_ProspectusTable  
Risk/Return [Heading] rr_RiskReturnHeading PRINCIPAL LIFETIME HYBRID 2060 FUND
Objective [Heading] rr_ObjectiveHeading Objective:
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Fund seeks a total return consisting of long-term growth of capital and current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment):
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
As a fund of funds, the Fund does not pay transaction costs, such as commissions, when it buys and sells shares of underlying funds (or “turns over” its portfolio). An underlying fund does pay transaction costs when it buys and sells portfolio securities, and a higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the examples, affect the performance of the underlying fund and the Fund.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 70.50%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund operates as a “target date fund” that invests according to an asset allocation strategy designed for investors having a retirement investment goal close to the year in the Fund’s name. The Fund's asset allocation will become more conservative over time as investment goals near (for example, retirement, which is assumed to begin at age 65) and investors become more risk-averse. The Fund is a fund of funds that invests in Institutional Class shares of Principal Funds, Inc. (“PFI”), with a majority of the Fund's assets invested in index funds. Its underlying funds consist of domestic and foreign equity funds, fixed-income funds, real asset funds, and other funds that aim to offer diversification beyond traditional equity and fixed-income securities. The Fund is managed by Principal Management Corporation (“Principal”).
Principal develops, implements and monitors the Fund's strategic or long-term asset class targets and target ranges, is responsible for an active rebalancing strategy designed to identify asset classes that appear attractive over the short term, and sets the percentage of Fund assets to be allocated to a particular asset class. Principal selects the underlying funds for each asset class and the target weights for each underlying fund and may shift asset class targets in response to normal evaluative processes, the shortening time horizon of the Fund or changes in market forces or Fund circumstances. Principal may add, remove, or substitute underlying funds at any time.
In selecting underlying funds and target weights, Principal considers both quantitative measures (e.g., past performance, expected levels of risk and returns, expense levels, diversification and style consistency) and qualitative factors (e.g., organizational stability, investment experience, investment and risk management processes, and information, trading, and compliance systems). There are no minimum or maximum percentages of assets that the Fund must invest in a specific asset class or underlying fund.
The underlying funds invest in growth and value stocks of small, medium, and large market capitalization companies, fixed-income securities, domestic and foreign (including those in emerging markets) securities, securities denominated in foreign currencies, investment companies (including index funds), and derivatives. A derivative is a financial arrangement, the value of which is derived from, or based on, a traditional security, asset, or market index. The underlying funds principally use equity index futures and options to manage equity exposure.
Approximately 15 years after its target year, the Fund's underlying fund allocation is expected to match that of the Principal LifeTime Hybrid Income Fund. At that time, the Fund may be combined with the Principal LifeTime Hybrid Income Fund if the Board of Directors determines that the combination is in the best interests of Fund shareholders. It is expected that at the target date in the Fund’s name, the shareholder will begin gradually withdrawing the account's value.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
The broad diversification of the Fund is designed to cushion severe losses in any one investment sector and moderate overall price volatility. However, the Fund is subject to the particular risks of the underlying funds in the proportions in which the Fund invests in them, and its share prices will fluctuate as the prices of underlying fund shares rise or fall with changing market conditions. If you sell your shares when their value is less than the price you paid, you will lose money. The Fund operates as a fund of funds and thus bears both its own expenses and, indirectly, its proportionate share of the expenses of the underlying funds in which it invests. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund that are inherent in the fund of funds, in alphabetical order, are:
Asset Allocation Risk. A fund's selection and weighting of asset classes may cause it to underperform other funds with a similar investment objective.
Conflict of Interest Risk. The Advisor and its affiliates earn different fees from different underlying funds and may have an incentive to allocate more fund-of-fund assets to underlying funds from which they receive higher fees.
Fund of Funds Risk. The performance and risks of a fund of funds directly correspond to the performance and risks of the underlying funds in which the fund invests. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this fund will provide adequate income at or through retirement.
The principal risks of investing in the Fund that are inherent in the underlying funds, in alphabetical order, are:
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and result in disproportionate losses that may be substantially greater than a fund's initial investment.
•
Futures. Futures involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the future,; possible lack of a liquid secondary market for a future and the resulting inability to close a future when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Emerging Markets Risk. Investments in emerging market countries may have more risk than those in developed market countries because the emerging markets are less developed and more illiquid. Emerging market countries can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile.
Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•
Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•
Small and Medium Market Capitalization Companies. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.
•
Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.
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.
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Index Fund Risk. More likely than not, an index fund will underperform the index due to cashflows and the fees and expenses of the fund. The correlation between fund performance and index performance may also be affected by changes in securities markets, changes in the composition of the index and the timing of purchases and sales of fund shares.
Investment Company Securities Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies in which the fund invests.
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates.
Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.
Risk Lose Money [Text] rr_RiskLoseMoney If you sell your shares when their value is less than the price you paid, you will lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The following 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 by calling 1-800-222-5852 or online at:
•
For Institutional Class and Class R-6 - www.principal.com.
The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Life of Fund results are measured from the date the Fund's shares were first sold (September 30, 2014).
For periods prior to the inception date of Class R-6 shares (August 24, 2015), the performance shown in the table for Class R-6 shares is based on the performance of the Fund's Institutional Class shares, adjusted to reflect the fees and expenses of Class R-6 shares. These adjustments for Class R-6 shares result in performance for such periods that is no higher than the historical performance of the Institutional Class shares, which were first sold on September 30, 2014.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following 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 by calling 1-800-222-5852 or online at: •For Institutional Class and Class R-6 - www.principal.com.The bar chart shows the investment returns of the Fund’s Institutional Class shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-222-5852
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.principal.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Total Returns as of December 31 (Institutional Class shares)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Highest return for a quarter during the period of the bar chart above:
Q4 '15
4.34
 %
Lowest return for a quarter during the period of the bar chart above:
Q3 ‘15
(7.25
)%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the periods ended December 31, 2015
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only and would be different for the other share classes.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns For the periods ended December 31, 2015
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund | S&P Target Date 2055 Plus Index  
Prospectus: rr_ProspectusTable  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses, or taxes)
Label rr_AverageAnnualReturnLabel S&P Target Date 2055+ Index (reflects no deduction for fees, expenses, or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.54%)
Since Inception rr_AverageAnnualReturnSinceInception 1.22%
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund | Principal LifeTime Hybrid 2060 Fund, Institutional Class  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLTHX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [33]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 319.03%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.51%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 319.54%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (318.98%) [34]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.56%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 57
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 5,948
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 $ 6,971
Annual Return 2015 rr_AnnualReturn2015 (0.20%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest return for a quarter during the period of the bar chart above:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2015
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.34%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest return for a quarter during the period of the bar chart above:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2015
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (7.25%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.20%)
Since Inception rr_AverageAnnualReturnSinceInception 2.68%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund | Principal LifeTime Hybrid 2060 Fund, Institutional Class | After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (0.90%)
Since Inception rr_AverageAnnualReturnSinceInception 1.10%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund | Principal LifeTime Hybrid 2060 Fund, Institutional Class | After Taxes on Distributions and Sales  
Prospectus: rr_ProspectusTable  
Label rr_AverageAnnualReturnLabel Institutional Class Return After Taxes on Distribution and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.11%)
Since Inception rr_AverageAnnualReturnSinceInception 1.67%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
PFI Prospectus | Principal LifeTime Hybrid 2060 Fund | Principal LifeTime Hybrid 2060 Fund, R-6  
Prospectus: rr_ProspectusTable  
Trading Symbol dei_TradingSymbol PLKTX
Shareholder Fee, Other rr_ShareholderFeeOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets none [33]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 134.38% [35]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.51%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 134.89%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (134.36%) [34]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.53%
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination February 28, 2018
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 54
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 6,784
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 6,167
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 6,106
Label rr_AverageAnnualReturnLabel Class R-6 Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.10%)
Since Inception rr_AverageAnnualReturnSinceInception 2.76%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 30, 2014
[1] Based on estimated expenses for the current fiscal year.
[2] Principal Management Corporation ("Principal"), 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 1.47% for Class A, 1.15% for Class P and 1.12% for Institutional Class shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[3] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[4] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[5] Based on estimated amounts for the current fiscal year (Class R-6).
[6] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[7] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[8] Based on estimated amounts for the current fiscal year (Class R-6).
[9] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[10] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[11] Based on estimated amounts for the current fiscal year (Class R-6).
[12] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[13] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[14] Based on estimated amounts for the current fiscal year (Class R-6).
[15] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[16] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[17] Based on estimated amounts for the current fiscal year (Class R-6).
[18] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[19] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[20] Based on estimated amounts for the current fiscal year (Class R-6).
[21] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[22] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[23] Based on estimated amounts for the current fiscal year (Class R-6).
[24] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[25] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[26] Based on estimated amounts for the current fiscal year (Class R-6).
[27] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[28] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[29] Based on estimated amounts for the current fiscal year (Class R-6).
[30] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced.
[31] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[32] Based on estimated amounts for the current fiscal year (Class R-6).
[33] Management Fees in the table have been restated to reflect current fees. Effective March 1, 2016, the Management Fees were reduced
[34] Principal Management Corporation ("Principal"), 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 0.05% for Institutional and 0.02% for R-6 shares. It is expected that the expense limits will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limits prior to the end of the period.
[35] Based on estimated amounts for the current fiscal year (Class R-6)