rr_RiskReturnAbstract

Document Type

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Other

Document Period End Date

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Jun. 16, 2014

Registrant Name

dei_EntityRegistrantName

PRINCIPAL FUNDS INC

Central Index Key

dei_EntityCentralIndexKey

0000898745

Amendment Flag

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false

Document Creation Date

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Jun. 16, 2014

Document Effective Date

dei_DocumentEffectiveDate

Jun. 16, 2014

Prospectus Date

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Dec. 30, 2013

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member]

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Supplement [Text Block]

ck0000898745_SupplementTextBlock

Supplement dated June 16, 2014

to the Classes Institutional, R-1, R-2, R-3, R-4, R-5 and S Shares Prospectus

for Principal Funds, Inc.

dated December 30, 2013

(As supplemented on January 2, 2014, February 7, 2014, March 7, 2014,

March 14, 2014, and April 28, 2014)

This supplement updates information currently in the Prospectus. Retain this supplement with the Prospectus.

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member]

Bar Chart and Performance Table [Heading]

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Risk/Return [Heading]

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DIVERSIFIED REAL ASSET FUND

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Performance Delete the index information in the Average Annual Total Returns table and substitute:

Performance Table Closing [Text Block]

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Delete the last paragraph in the Performance section and substitute:

Performance of a blended index shows how the Fund’s performance compares to a blend of indices with similar investment objectives. Performance of the components of the blended index are also shown. Effective March 1, 2014, the components of the Diversified Real Asset Custom Index changed to the following: 15% Barclays U.S. Treasury TIPS Index, 20% S&P Leveraged Loan 100 Index, 17% Dow Jones Brookfield Global Infrastructure Index, 15% Dow Jones UBS Commodity Index (will be renamed the “Bloomberg Commodity Index” on July 1, 2014), 14% Tortoise MLP Index, 8% FTSE EPRA/NAREIT Developed Index, 4% S&P Global Timber and Forestry Index, 4% S&P Commodity Producers Agribusiness Index and 3% blend of 60% MSCI World Energy Sector Index and 40% MSCI World Materials Sector Index. The custom or blended index returns reflect the allocation in effect for the time period(s) for which fund returns are disclosed. Previous weightings or allocations of the custom or blended index are not restated.

Caption

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Average Annual Total Returns For the periods ended 12/31/2012

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | Barclays US Treasury Tips Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

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rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

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Barclays U.S. Treasury TIPS Index (reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnYear01

6.98%

rr_AverageAnnualReturnSinceInception

9.17%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | S&P Leveraged Loan 100 Index

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rr_AverageAnnualReturnLabel

S&P Leveraged Loan 100 Index

rr_AverageAnnualReturnYear01

10.51%

rr_AverageAnnualReturnSinceInception

6.20%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | Dow Jones Brookfield Global Infrastructure Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

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rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnLabel

Dow Jones Brookfield Global Infrastructure Index (reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnYear01

16.01%

rr_AverageAnnualReturnSinceInception

14.75%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | Dow Jones UBS Commodity Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_RiskReturnAbstract

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

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Dow Jones UBS Commodity Index (reflects no deduction for fees, expenses, or taxes)

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(1.06%)

rr_AverageAnnualReturnSinceInception

1.73%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | Tortoise MLP Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

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rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnLabel

Tortoise MLP Index (reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnYear01

5.45%

rr_AverageAnnualReturnSinceInception

16.00%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | FTSE EPRA/NAREIT Developed Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_RiskReturnAbstract

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnLabel

FTSE EPRA/NAREIT Developed Index (reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnYear01

28.65%

rr_AverageAnnualReturnSinceInception

13.10%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | S&P Global Timber and Forestry Index

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rr_AverageAnnualReturnLabel

S&P Global Timber and Forestry Index

rr_AverageAnnualReturnYear01

22.95%

rr_AverageAnnualReturnSinceInception

5.31%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | S&P Commodity Producers Agribusiness Index

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S&P Commodity Producers Agribusiness Index

rr_AverageAnnualReturnYear01

18.18%

rr_AverageAnnualReturnSinceInception

8.56%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | MSCI World (Energy Sector) Index

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rr_AverageAnnualReturnLabel

MSCI World (Energy Sector) Index

rr_AverageAnnualReturnYear01

1.87%

rr_AverageAnnualReturnSinceInception

5.00%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | MSCI World (Materials Sector) Index

rr_RiskReturnAbstract

rr_AverageAnnualReturnLabel

MSCI World (Materials Sector) Index

rr_AverageAnnualReturnYear01

11.30%

rr_AverageAnnualReturnSinceInception

2.52%

PFI Prospectus - Institutional, R-1, R-2, R-3, R-4, R-5 and S Class Shares [Member] | Diversified Real Asset Fund [Member] | Diversified Real Asset Custom Index [Member]

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_RiskReturnAbstract

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnLabel

Diversified Real Asset Custom Index (reflects no deduction for fees, expenses, or taxes)

rr_AverageAnnualReturnYear01

8.68%