You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information atwww.troweprice.com/prospectus. You can also request this information without charge by contacting T. Rowe Price at 1‑800‑638‑5660 or info@troweprice.com or contacting your intermediary.

Material Fund Change Notice [Text Block]

Additional Information Phone Number

1‑800‑638‑5660

Additional Information Email

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Additional Information Website

www.troweprice.com/prospectus

Expenses [Text Block]

What were the fund costs for the last year? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Equity Index 500 Fund - Investor Class	$21	0.19%

Expenses Paid, Amount

$ 21

Expense Ratio, Percent

0.19%

Factors Affecting Performance [Text Block]

What drove fund performance during the past 12 months?

Major U.S. stock market indexes rose in 2025. After a challenging start to the year stemming from new U.S. tariffs, equities advanced as economic growth and corporate earnings remained favorable, investors favored artificial intelligence-related and other high-growth businesses, and Congress passed tax legislation that should help stimulate the economy. In addition, signs of a weakening labor market prompted the Federal Reserve to resume reducing short-term interest rates in the latter part of the year. The central bank lowered rates in September, October, and December.
Information technology names produced robust results during the period as the sector benefited from strong investor interest in companies expected to benefit from artificial intelligence developments. Semiconductors and semiconductor equipment and software companies performed very well during the year, as NVIDIA and Microsoft were two of the top-performing companies in the portfolio.
No sectors detracted from absolute returns during the reporting period.
The trajectories of the economy, corporate earnings, and interest rates are unpredictable, and investor sentiment toward the broad market and various market segments could change without warning. Our main task is not to determine which stocks or sectors may perform best but, rather, to replicate the structure of the S&P 500 Index and closely track its performance.

Performance Past Does Not Indicate Future [Text]

The fund’s past performance is not a good predictor of the fund’s future performance.

Average Annual Return [Table Text Block]

Average Annual Total Returns

	1 Year	5 Years	10 Years
Equity Index 500 Fund (Investor Class)	17.65%	14.21%	14.59%
S&P 500 Index (Regulatory/Strategy Benchmark)	17.88	14.42	14.82

The preceding line graph shows the value of a hypothetical $10,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The fund’s performance information included in the line graph and table above is compared with a regulatory required index that represents an overall securities market (Regulatory Benchmark). In addition, the line graph and table may also include one or more indexes that more closely aligns to the fund's investment strategy (Strategy Benchmark(s)). The fund's total return figures reflect the reinvestment of dividends and capital gains, if any.Neither the fund’s returns nor the index returns reflect the deduction of taxes that a shareholder would pay on fund distributions or redemptions of fund shares.The fund’s past performance is not a good predictor of the fund’s future performance.Updated performance information can be found at www.troweprice.com.

No Deduction of Taxes [Text Block]

Neither the fund’s returns nor the index returns reflect the deduction of taxes that a shareholder would pay on fund distributions or redemptions of fund shares.

Updated Performance Information Location [Text Block]

Updated performance information can be found at www.troweprice.com.

Distribution of Capital [Text Block]

The fund's total return figures reflect the reinvestment of dividends and capital gains, if any.

AssetsNet

$ 37,898,759,000

Holdings Count | Holding

506

Advisory Fees Paid, Amount

$ 6,207,000

InvestmentCompanyPortfolioTurnover

3.20%

Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Total Net Assets (000s)$37,898,759
Number of Portfolio Holdings506

Holdings [Text Block]

Sector Allocation (as a % of Net Assets)

Information Technology	34.3%
Financials	13.4
Communication Services	10.7
Consumer Discretionary	10.3
Health Care	9.5
Industrials & Business Services	8.2
Consumer Staples	4.7
Energy	2.8
Utilities	2.2
Other	3.9

Largest Holdings [Text Block]

Top Ten Holdings (as a % of Net Assets)

NVIDIA	7.7%
Apple	6.9
Microsoft	6.1
Alphabet	5.6
Amazon.com	3.8
Broadcom	2.8
Meta Platforms	2.5
Tesla	2.2
Berkshire Hathaway	1.6
JPMorgan Chase	1.5

Updated Prospectus Web Address

www.troweprice.com/paperless

C000159677

Shareholder Report [Line Items]

Fund Name

Equity Index 500 Fund

Class Name

I Class

Trading Symbol

PRUIX

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

Material Fund Change Notice [Text Block]

Additional Information Phone Number

1‑800‑638‑5660

Additional Information Email

Additional Information Website

www.troweprice.com/prospectus

Expenses [Text Block]

What were the fund costs for the last year? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Equity Index 500 Fund - I Class	$5	0.05%

Expenses Paid, Amount

$ 5

Expense Ratio, Percent

0.05%

Factors Affecting Performance [Text Block]

What drove fund performance during the past 12 months?

Major U.S. stock market indexes rose in 2025. After a challenging start to the year stemming from new U.S. tariffs, equities advanced as economic growth and corporate earnings remained favorable, investors favored artificial intelligence-related and other high-growth businesses, and Congress passed tax legislation that should help stimulate the economy. In addition, signs of a weakening labor market prompted the Federal Reserve to resume reducing short-term interest rates in the latter part of the year. The central bank lowered rates in September, October, and December.
Information technology names produced robust results during the period as the sector benefited from strong investor interest in companies expected to benefit from artificial intelligence developments. Semiconductors and semiconductor equipment and software companies performed very well during the year, as NVIDIA and Microsoft were two of the top-performing companies in the portfolio.
No sectors detracted from absolute returns during the reporting period.
The trajectories of the economy, corporate earnings, and interest rates are unpredictable, and investor sentiment toward the broad market and various market segments could change without warning. Our main task is not to determine which stocks or sectors may perform best but, rather, to replicate the structure of the S&P 500 Index and closely track its performance.

Performance Past Does Not Indicate Future [Text]

The fund’s past performance is not a good predictor of the fund’s future performance.

Average Annual Return [Table Text Block]

Average Annual Total Returns

	1 Year	5 Years	10 Years
Equity Index 500 Fund (I Class)	17.81%	14.37%	14.75%
S&P 500 Index (Regulatory/Strategy Benchmark)	17.88	14.42	14.82

The preceding line graph shows the value of a hypothetical $500,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The fund’s performance information included in the line graph and table above is compared with a regulatory required index that represents an overall securities market (Regulatory Benchmark). In addition, the line graph and table may also include one or more indexes that more closely aligns to the fund's investment strategy (Strategy Benchmark(s)). The fund's total return figures reflect the reinvestment of dividends and capital gains, if any.Neither the fund’s returns nor the index returns reflect the deduction of taxes that a shareholder would pay on fund distributions or redemptions of fund shares.The fund’s past performance is not a good predictor of the fund’s future performance.Updated performance information can be found at www.troweprice.com.

No Deduction of Taxes [Text Block]

Neither the fund’s returns nor the index returns reflect the deduction of taxes that a shareholder would pay on fund distributions or redemptions of fund shares.

Updated Performance Information Location [Text Block]

Updated performance information can be found at www.troweprice.com.

Distribution of Capital [Text Block]

The fund's total return figures reflect the reinvestment of dividends and capital gains, if any.

AssetsNet

$ 37,898,759,000

Holdings Count | Holding

506

Advisory Fees Paid, Amount

$ 6,207,000

InvestmentCompanyPortfolioTurnover

3.20%

Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Total Net Assets (000s)$37,898,759
Number of Portfolio Holdings506

Holdings [Text Block]

Sector Allocation (as a % of Net Assets)

Information Technology	34.3%
Financials	13.4
Communication Services	10.7
Consumer Discretionary	10.3
Health Care	9.5
Industrials & Business Services	8.2
Consumer Staples	4.7
Energy	2.8
Utilities	2.2
Other	3.9

Largest Holdings [Text Block]

Top Ten Holdings (as a % of Net Assets)

NVIDIA	7.7%
Apple	6.9
Microsoft	6.1
Alphabet	5.6
Amazon.com	3.8
Broadcom	2.8
Meta Platforms	2.5
Tesla	2.2
Berkshire Hathaway	1.6
JPMorgan Chase	1.5

Updated Prospectus Web Address

www.troweprice.com/paperless

C000219327

Shareholder Report [Line Items]

Fund Name

Equity Index 500 Fund

Class Name

Z Class

Trading Symbol

TRHZX

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

Material Fund Change Notice [Text Block]

Additional Information Phone Number

1‑800‑638‑5660

Additional Information Email

Additional Information Website

www.troweprice.com/prospectus

Expenses [Text Block]

What were the fund costs for the last year? (based on a hypothetical $10,000 investment)

	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Equity Index 500 Fund - Z Class	$0	0.00%

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.00%

Factors Affecting Performance [Text Block]

What drove fund performance during the past 12 months?

Major U.S. stock market indexes rose in 2025. After a challenging start to the year stemming from new U.S. tariffs, equities advanced as economic growth and corporate earnings remained favorable, investors favored artificial intelligence-related and other high-growth businesses, and Congress passed tax legislation that should help stimulate the economy. In addition, signs of a weakening labor market prompted the Federal Reserve to resume reducing short-term interest rates in the latter part of the year. The central bank lowered rates in September, October, and December.
Information technology names produced robust results during the period as the sector benefited from strong investor interest in companies expected to benefit from artificial intelligence developments. Semiconductors and semiconductor equipment and software companies performed very well during the year, as NVIDIA and Microsoft were two of the top-performing companies in the portfolio.
No sectors detracted from absolute returns during the reporting period.
The trajectories of the economy, corporate earnings, and interest rates are unpredictable, and investor sentiment toward the broad market and various market segments could change without warning. Our main task is not to determine which stocks or sectors may perform best but, rather, to replicate the structure of the S&P 500 Index and closely track its performance.

Performance Past Does Not Indicate Future [Text]

The fund’s past performance is not a good predictor of the fund’s future performance.

Average Annual Return [Table Text Block]

Average Annual Total Returns

	1 Year	5 Years	Since Inception 3/16/20
Equity Index 500 Fund (Z Class)	17.87%	14.42%	21.77%
S&P 500 Index (Regulatory/Strategy Benchmark)	17.88	14.42	21.77

Performance Inception Date

Mar. 16, 2020

No Deduction of Taxes [Text Block]

Neither the fund’s returns nor the index returns reflect the deduction of taxes that a shareholder would pay on fund distributions or redemptions of fund shares.

Updated Performance Information Location [Text Block]

Updated performance information can be found at www.troweprice.com.

Distribution of Capital [Text Block]

The fund's total return figures reflect the reinvestment of dividends and capital gains, if any.

AssetsNet

$ 37,898,759,000

Holdings Count | Holding

506

Advisory Fees Paid, Amount

$ 6,207,000

InvestmentCompanyPortfolioTurnover

3.20%

Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Total Net Assets (000s)$37,898,759
Number of Portfolio Holdings506

Holdings [Text Block]

Sector Allocation (as a % of Net Assets)

Information Technology	34.3%
Financials	13.4
Communication Services	10.7
Consumer Discretionary	10.3
Health Care	9.5
Industrials & Business Services	8.2
Consumer Staples	4.7
Energy	2.8
Utilities	2.2
Other	3.9

Largest Holdings [Text Block]

Top Ten Holdings (as a % of Net Assets)

NVIDIA	7.7%
Apple	6.9
Microsoft	6.1
Alphabet	5.6
Amazon.com	3.8
Broadcom	2.8
Meta Platforms	2.5
Tesla	2.2
Berkshire Hathaway	1.6
JPMorgan Chase	1.5

Updated Prospectus Web Address