| Label | Element | Value |
|---|---|---|
| BNY Mellon Fixed Income Completion Funds (FICS) - CP | ||
| Prospectus [Line Items] | oef_ProspectusLineItems | |
| Risk/Return [Heading] | oef_RiskReturnHeading | BNY Mellon Fixed Income Completion Funds (FICS) — CP |
| Strategy Narrative [Text Block] | oef_StrategyNarrativeTextBlock | The following information supplements and supersedes any contrary information in the sections "BNY Mellon Fixed Income Completion Funds (FICS) — CP – Principal Investment Strategy" in the summary prospectus and "Fund Summary – BNY Mellon Fixed Income Completion Funds (FICS) — CP – Principal Investment Strategy" in the prospectus: The fund may invest in the securities of U.S. and foreign issuers, including up to 40% of its net assets in securities of issuers in emerging market countries, and securities denominated in a currency other than the U.S. dollar. |
| Supplement to Prospectus [Text Block] | oef_SupplementToProspectusTextBlock | BNY MELLON INVESTMENT FUNDS II, INC. Supplement to Current Summary Prospectus and Prospectus |