Document and Entity Information	Total
Prospectus:
Document Type	485BPOS
Document Period End Date	Dec. 31, 2021
Entity Registrant Name	BNY Mellon Investment Funds III
Entity Central Index Key	0000053808
Entity Inv Company Type	N-1A
Amendment Flag	false
Document Creation Date	Apr. 22, 2022
Document Effective Date	Apr. 29, 2022
Prospectus Date	Apr. 29, 2022
BNY Mellon High Yield Fund \| Class A
Prospectus:
Trading Symbol	DPLTX
BNY Mellon High Yield Fund \| Class C
Prospectus:
Trading Symbol	PTHIX
BNY Mellon High Yield Fund \| Class I
Prospectus:
Trading Symbol	DLHRX

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The date the document was made available and submitted, in YYYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.

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The date when a document, upon receipt and acceptance, becomes officially effective, in YYYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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