0000719451 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member fmr:C000014122Member 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member fmr:ReturnBeforeTaxesMember fmr:C000014122Member 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member rr:AfterTaxesOnDistributionsMember fmr:C000014122Member 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member rr:AfterTaxesOnDistributionsAndSalesMember fmr:C000014122Member 2024-01-29 2024-01-29 0000719451 fmr:FidelityLimitedTermGovernmentFund-PROMember fmr:S000005156Member fmr:IndexLB069Member 2024-01-29 2024-01-29 iso4217:USD pure 485BPOS 2023-11-30 false 0000719451 N-1A Fidelity Advisor Series IV Fund Summary Fund: Fidelity® Limited Term Government Fund Investment Objective Fidelity® Limited Term Government Fund seeks a high level of current income in a manner consistent with preserving principal. Fee Table The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. In addition to the fees and expenses described below, your broker may also require you to pay brokerage commissions on purchases and sales of the fund. Shareholder fees 0 Annual Operating Expenses 0.0020 0 0.0010 0.0030 Adjusted to reflect current fees. 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. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated: 31 97 169 381 Portfolio Turnover 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 and may result in higher taxes when fund shares are held in a taxable account. 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 149% of the average value of its portfolio. 1.49 Principal Investment Strategies Normally investing at least 80% of assets in U.S. Government securities and repurchase agreements for those securities.Investing in U.S. Government securities issued by entities that are chartered or sponsored by Congress but whose securities are neither issued nor guaranteed by the U.S. Treasury.Investing in instruments related to U.S. Government securities.Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. 1-5 Year Government Bond Index.Normally maintaining a dollar-weighted average maturity between two and five years.Allocating assets across different market sectors and maturities.Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Principal Investment Risks Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease. Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change. Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. High Portfolio Turnover. High portfolio turnover (more than 100%) may result in increased transaction costs and potentially higher capital gains or losses. The effects of higher than normal portfolio turnover may adversely affect the fund's performance. An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.  You could lose money by investing in the fund. Performance 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 over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information. 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 over various periods of time. Past performance (before and after taxes) is not an indication of future performance. www.fidelity.com Year-by-Year Returns 0.0128 0.0054 0.0058 0.0057 0.0115 0.0375 0.0391 -0.0146 -0.0618 0.0411    Highest Quarter Return 0.0369 2020-03-31    Lowest Quarter Return -0.0348 2022-03-31 Average Annual Returns After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares. Return Before Taxes 0.0411 0.0074 0.0078 Return After Taxes on Distributions 0.0317 0.0019 0.0028 Return After Taxes on Distributions and Sale of Fund Shares 0.0242 0.0033 0.0038 Bloomberg U.S. 1-5 Year Government Bond Index 0.0439 0.0118 0.0113 AAdjusted to reflect current fees.