Label

Element

Value

Prospectus:

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Document Type

dei_DocumentType

497

Document Period End Date

dei_DocumentPeriodEndDate

Oct. 31, 2019

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. 31, 2020

Document Effective Date

dei_DocumentEffectiveDate

Jul. 31, 2020

Prospectus Date

rr_ProspectusDate

Mar. 01, 2020

PFI Prospectus [Member] | LargeCap Growth Fund I

Prospectus:

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Supplement [Text Block]

ck0000898745_SupplementTextBlock

Principal Funds, Inc.

Supplement dated July 31, 2020

to the Prospectus dated March 1, 2020

(as previously supplemented)

This supplement updates information currently in the Prospectus. Please retain this supplement for future reference.

SUMMARY FOR LARGECAP GROWTH FUND I

On July 30, 2020, the Board of Directors of Principal Funds, Inc. approved a change to the Fund’s diversification classification from “diversified” to “non-diversified” and a change to the related fundamental investment restriction (together, the “Proposed Change”). Fund shareholders of record on August 19, 2020 are entitled to vote on the Proposed Change at a Special Meeting of Shareholders of the Fund tentatively scheduled for October 28, 2020. Additional information about the Proposed Change will be provided in the Proxy Statement that is expected to be sent to record date Fund shareholders on or about September 4, 2020. The Proposed Change, if approved by Fund shareholders, is expected to be effective on or about November 1, 2020 (the “Change Date”). However, the Fund’s officers have the discretion to change these dates.

Risk/Return [Heading]

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SUMMARY FOR LARGECAP GROWTH FUND I

Strategy [Heading]

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On or about the Change Date, under Principal Investment Strategies, add the following after the second paragraph:

Strategy Narrative [Text Block]

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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. As a result, changes in the value of a single investment could cause greater fluctuations in the Fund's share price than would occur in a more diversified fund.

Risk [Heading]

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On or about the Change Date, in the Principal Risks section, add the following to the alphabetical list of risks:

Risk Narrative [Text Block]

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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.