Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in California municipal obligations (securities issued by or on behalf of state or local governments and other public authorities). Generally, these municipal obligations pay interest that is exempt from State personal income tax and federal income tax. These obligations may include bonds that generate interest payments that are subject to the alternative minimum tax. Under normal circumstances, the Fund maintains an average portfolio duration that is within ±50% of the duration of the Barclays California Municipal Bond Index, which as of December 31, 2012 was 6.50 years. The Fund may invest up to 20% of its assets in below investment grade bonds (sometimes called “high yield bonds” or "junk bonds") which are rated at the time of purchase Ba1 or lower by Moody's and BB+ or lower by S&P (if the bond has been rated by only one of those agencies, that rating will determine whether the bond is below investment grade; if the bond has not been rated by either of those agencies, the Sub-Advisor will determine whether the bond is of a quality comparable to those rated below investment grade). The Fund also invests in inverse floating rate obligations, which are generally more volatile than other types of municipal obligations.

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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.

PFI Prospectus - Class A, B, C, P | High Yield Fund [Member]

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High Yield Fund

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For the periods ended December 31, 2012

PFI Prospectus - Class A, B, C, P | Inflation Protection Fund [Member]

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Inflation Protection Fund

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The Fund invests primarily in inflation-indexed bonds of varying maturities issued by the U.S. and non-U.S. governments, their agencies or instrumentalities, and U.S. and non-U.S. corporations. Inflation-indexed bonds are fixed income securities that are structured to provide protection against inflation. The value of the bond's principal or the interest income paid on the bond is adjusted to track changes in an official inflation measure. The U.S. Treasury uses the Consumer Price Index for Urban Consumers as the inflation measure. Inflation-indexed bonds issued by a foreign government are generally adjusted to reflect a comparable inflation index, calculated by that government. Under normal circumstances, the Fund maintains an average portfolio duration that is within ±20% of the duration of the Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index. The Fund also invests in foreign securities, U.S. Treasuries and agency securities. The Fund utilizes derivative strategies, including financial futures contracts, swaps, currency forwards, and options for purposes of managing or adjusting the risk profile (for example, duration) of the Fund. The Fund actively trades portfolio securities.

PFI Prospectus - Class A, B, C, P | Principal LifeTime Strategic Income Fund [Member]

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Principal LifeTime Strategic Income Fund

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The underlying funds invest in equity securities, growth and value stocks, fixed-income securities (including high yield or “junk” bonds), domestic and foreign securities, investment companies (including index funds), real estate securities, derivatives, mortgage-backed and asset-backed securities, and U.S. government and U.S. government-sponsored securities.

PFI Prospectus - Class A, B, C, P | Principal LifeTime 2010 Fund [Member]

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Principal LifeTime 2010 Fund

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The underlying funds invest in equity securities, growth and value stocks, fixed-income securities (including high yield or “junk” bonds), domestic and foreign securities, securities denominated in foreign currencies, investment companies (including index funds), real estate securities, derivatives, mortgage-backed and asset-backed securities, and U.S. government and U.S. government-sponsored securities.

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PFI Prospectus - Class A, B, C, P | Strategic Asset Management Flexible Income Portfolio [Member]

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Strategic Asset Management ("SAM") Flexible Income Portfolio

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•	Generally invests between 55% and 95% of its assets in fixed-income funds, and less than 40% in any one fixed-income fund (fixed-income funds that generally invest in fixed income instruments such as real estate securities, mortgage-backed securities, government and government-sponsored securities, corporate bonds and preferred securities)

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Real Estate Securities Risk. Real estate securities are subject to the risks associated with direct ownership of real estate, including declines in value, adverse economic conditions, increases in expenses, regulatory changes and environmental problems. Investing in securities of companies in the real estate industry, subjects a fund to the special risks associated with the real estate market including factors such as loss to casualty or condemnation, changes in real estate values, property taxes, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents, and the management skill and creditworthiness of the issuer.

PFI Prospectus - Class A, B, C, P | Strategic Asset Management Conservative Balanced Portfolio [Member]

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Strategic Asset Management ("SAM") Conservative Balanced Portfolio

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Generally invests between 40% and 80% of its assets in fixed-income funds, and less than 40% in any one fixed-income fund (fixed-income funds that generally invest in fixed income instruments such as real estate securities, mortgage-backed securities, government and government-sponsored securities, and corporate bonds)

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PFI Prospectus - Class A, B, C, P | Strategic Asset Management Balanced Portfolio [Member]

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Strategic Asset Management ("SAM") Balanced Portfolio

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•	Generally invests between 20% and 60% of its assets in fixed-income funds, and less than 40% in any one fixed-income fund (fixed-income funds that generally invest in fixed income instruments such as real estate securities, mortgage-backed securities, government and government-sponsored securities, and corporate bonds)

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PFI Prospectus - Class A, B, C, P | Strategic Asset Management Conservative Growth Portfolio [Member]

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Strategic Asset Management ("SAM") Conservative Growth Portfolio

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•	Generally invests between 0% and 40% of its assets in fixed-income funds, and less than 30% in any one fixed-income fund (fixed-income funds that generally invest in fixed-income instruments such as real estate securities, government and government-sponsored securities and corporate bonds)

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PFI Prospectus - Class A, B, C, P | Strategic Asset Management Strategic Growth Portfolio [Member]

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Strategic Asset Management ("SAM") Strategic Growth Portfolio

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•	Could invest between 0% and 25% of its assets in fixed-income funds (most likely between 0% and 10%), and generally less than 25% in any one fixed-income fund (fixed-income funds that generally invest in fixed income instruments such as government and government-sponsored securities)