The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the performance of the fund's Class I shares from year to year. The table compares the average annual total returns of the fund's shares to those of the Bloomberg U.S. Aggregate Bond Index, a broad measure of market performance. The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. Performance for each share class will vary due to differences in expenses. More recent performance information may be available at www.bny.com/investments.

Performance Information Illustrates Variability of Returns [Text]

The following bar chart and table provide some indication of the risks of investing in the fund.

Bar Chart [Heading]

Year-by-Year Total Returns as of 12/31 each year (%)

Performance Table Narrative

After-tax performance is shown only for Class I shares. After-tax performance of the fund's other share class will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through U.S. tax-deferred arrangements such as 401(k) plans or individual retirement accounts. Returns after taxes on distributions and

sale of fund shares may be higher than returns before taxes or returns after taxes on distributions due to an assumed tax benefit from losses on a sale of the fund's shares at the end of the period.

Performance Table Not Relevant to Tax Deferred

Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through U.S. tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Performance [Table]

Average Annual Total Returns - BNY Mellon Bond Market Index Fund		12 Months Ended	60 Months Ended	120 Months Ended
	Oct. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Bloomberg U.S. Aggregate Bond Index reflects no deductions for fees, expenses or taxes \| Average Annual Return, Label [Optional Text]	Bloomberg U.S. Aggregate Bond Index
Bloomberg U.S. Aggregate Bond Index reflects no deductions for fees, expenses or taxes \| Average Annual Return, Percent		7.30%	(0.36%)	2.01%
Class I Shares \| Average Annual Return, Label [Optional Text]	returns before taxes
Class I Shares \| Average Annual Return, Percent		7.05%	(0.57%)	1.82%
Class I Shares \| After Taxes on Distributions \| Average Annual Return, Label [Optional Text]	returns after taxes on distributions
Class I Shares \| After Taxes on Distributions \| Average Annual Return, Percent		5.40%	(1.85%)	0.59%
Class I Shares \| After Taxes on Distributions and Sales \| Average Annual Return, Label [Optional Text]	returns after taxes on distributions and sale of fund shares
Class I Shares \| After Taxes on Distributions and Sales \| Average Annual Return, Percent		4.14%	(0.96%)	0.87%
Investor \| Average Annual Return, Label [Optional Text]	returns before taxes
Investor \| Average Annual Return, Percent		6.66%	(0.82%)	1.56%

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

reflects no deductions for fees, expenses or taxes

Highest Quarterly Return, Label [Optional Text]

Best Quarter

Highest Quarterly Return, Date

Dec. 31, 2023

Lowest Quarterly Return

(5.98%)

Bar Chart and Performance Table [Heading]

Performance

Performance Past Does Not Indicate Future [Text]

The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Performance Additional Market Index [Text]

The table compares the average annual total returns of the fund's Class I shares to those of the S&P 500® Index, a broad measure of market performance.

Bar Chart Closing [Text Block]

During the periods shown in the chart:
Best Quarter
2020, Q2: 20.48
Worst Quarter
2020, Q1: (19.63)

Performance Table Uses Highest Federal Rate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes.

Performance Table Explanation after Tax Higher

Returns after taxes on distributions and sale of fund shares may be higher than returns before taxes or returns after taxes on distributions due to an assumed tax benefit from losses on a sale of the fund's shares at the end of the period.

Average Annual Return, Caption [Optional Text]

Average Annual Total Returns (as of 12/31/25)

Performance Availability Website Address [Text]

www.bny.com/investments

Prospectus [Line Items]

Highest Quarterly Return

20.48%

Lowest Quarterly Return, Label [Optional Text]

Worst Quarter

Lowest Quarterly Return, Date

Mar. 31, 2020