Risk/Return Detail Data - VIPSectorFunds-InitialComboPRO	Apr. 30, 2025 USD ($)
Risk/Return:
Registrant Name	Variable Insurance Products Fund IV
VIPSectorFunds-InitialComboPRO | VIP Financials Portfolio
Risk/Return:
Risk/Return [Heading]	Fund Summary Fund /Class: VIP Financials Portfolio /Initial Class
Objective [Heading]	Investment Objective
Objective, Primary [Text Block]	VIP Financials Portfolio seeks capital appreciation.
Expense [Heading]	Fee Table
Expense Narrative [Text Block]	The following table describes the fees and expenses that may be incurred, directly or indirectly, when you, as a variable product owner, buy, hold, and sell interests in a separate account that invests in shares of the fund. The table does not include any fees or other expenses of any variable annuity or variable life insurance product; if it did, overall fees and expenses would be higher.
Shareholder Fees Caption [Text]	Fees
(fees paid directly from your investment)
Operating Expenses Caption [Text]	Annual Operating Expenses
Portfolio Turnover [Heading]	Portfolio Turnover
Portfolio Turnover [Text Block]	The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 37 % of the average value of its portfolio.
Portfolio Turnover, Rate	37.00%
Expenses Restated to Reflect Current [Text]	Adjusted to reflect current fees.
Expense Example Narrative [Text Block]	This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. This example does not include any fees or other expenses of any variable annuity or variable life insurance product; if it did, overall expenses would be higher. For every $10,000 invested, here's how much you, as a variable product owner, would pay in total expenses if all interests in a separate account that invests in shares of the fund were redeemed at the end of each time period indicated:
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	Normally investing primarily in common stocks. Normally investing at least 80% of assets in securities of companies principally engaged in providing financial services to consumers and industry. These companies may include, for example, investment banks; brokerage and asset management firms; companies providing life, health, and/or property and casualty insurance; commercial banks; financial institutions providing mortgages and mortgage-related services, including mortgage real estate investment trusts (REITs); providers of personal loans and other consumer payment and finance services; credit agencies; stock exchanges; investment management firms; institutions providing custody services; and reinsurance companies. For purposes of the fund's policy to normally invest at least 80% of its assets in securities of companies principally engaged in the business activity or activities identified for the fund, Fidelity may consider a company to be principally engaged in the designated business activity or activities based on: (i) the level of a company's assets, income, sales, or profits that are committed to, derived from, or related to the designated business activity or activities, or (ii) whether a third party has given the company an industry or sector classification consistent with the designated business activity or activities. Whether a company is principally engaged in the designated business activity or activities can be determined under any of these factors. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives. Investing in domestic and foreign issuers. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.
Strategy Portfolio Concentration [Text]	Normally investing at least 80% of assets in securities of companies principally engaged in providing financial services to consumers and industry.
Risk [Heading]	Principal Investment Risks
Bar Chart and Performance Table [Heading]	Performance
Performance Narrative [Text Block]	The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance is not an indication of future performance. Returns for shares of the fund do not include the effect of any sales charges or other expenses of any variable annuity or variable life insurance product; if they did, returns for shares of the fund would be lower.
Performance Information Illustrates Variability of Returns [Text]	The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Past Does Not Indicate Future [Text]	Past performance is not an indication of future performance.
Bar Chart [Heading]	Year-by-Year Returns
Bar Chart Does Not Reflect Sales Loads [Text]	Returns for shares of the fund do not include the effect of any sales charges or other expenses of any variable annuity or variable life insurance product; if they did, returns for shares of the fund would be lower.
Highest Quarterly Return, Label	Highest Quarter Return
Highest Quarterly Return, Date	Dec. 31, 2020
Highest Quarterly Return	30.69%
Lowest Quarterly Return, Label	Lowest Quarter Return
Lowest Quarterly Return, Date	Mar. 31, 2020
Lowest Quarterly Return	(35.04%)
Performance Table Heading	Average Annual Returns
VIPSectorFunds-InitialComboPRO | VIP Financials Portfolio | VIP Financials Portfolio - Initial Class
Risk/Return:
Management fee	0.58%	[1]
Distribution and/or Service (12b-1) fees	none
Other expenses	0.03%	[1]
Total annual operating expenses	0.61%
1 year	$ 62
3 years	195
5 years	340
10 years	$ 762
2015	(3.69%)
2016	18.72%
2017	21.25%
2018	(15.73%)
2019	34.33%
2020	0.77%
2021	33.19%
2022	(8.33%)
2023	14.73%
2024	32.73%
VIPSectorFunds-InitialComboPRO | VIP Financials Portfolio | Return Before Taxes | VIP Financials Portfolio - Initial Class
Risk/Return:
Label	Initial Class
Past 1 year	32.73%
Past 5 years	13.38%
Past 10 years	11.39%
VIPSectorFunds-InitialComboPRO | VIP Financials Portfolio | SP001
Risk/Return:
Label	S&P 500® Index
Past 1 year	25.02%
Past 5 years	14.53%
Past 10 years	13.10%
VIPSectorFunds-InitialComboPRO | VIP Financials Portfolio | IXZ92
Risk/Return:
Label	MSCI U.S. IMI Financials 5% Capped Linked Index
Past 1 year	30.21%
Past 5 years	11.96%
Past 10 years	11.40%

[1] A Adjusted to reflect current fees.