Investing primarily in a combination of Fidelity® U.S. equity funds, international equity funds, bond funds, and short-term funds (underlying Fidelity® funds), some of which are actively managed and others of which are passively managed, meaning they seek to provide investment results that correspond to the total return of a specific index. Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity Flex® Freedom Blend Retirement Fund, approximately 15 to 20 years after the year 2020. Fidelity Management & Research Company LLC (FMR) (the Adviser) may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. The Adviser has begun transitioning the neutral asset allocation percentages to achieve the desired allocations.     The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds (including commodity funds), international equity funds, bond funds (including U.S. investment grade bond, international bond, short-term inflation-protected bond, long-term inflation-protected bond, and long-term treasury bond funds), and short-term funds. Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation. The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective. The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds (including commodity funds), bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class. The Adviser may also make active asset allocations within other asset classes (such as high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Designed for investors who retired in or within a few years of 2020 (target retirement date) at or around age 65. When the neutral asset allocation of a fund matches Fidelity Flex ®  Freedom Blend Retirement Fund's neutral asset allocation (approximately 15 to 20 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity Flex ®  Freedom Blend Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity Flex ®  Freedom Blend Retirement Fund.