Organization and Going Concern	12 Months Ended
Organization and Going Concern	Dec. 31, 2021
Organization and Going Concern [Abstract]
Organization and Going Concern	Note 1 – Organization and Going Concern AmBase Corporation (the “Company” or “AmBase”) is a Delaware corporation that was incorporated in 1975. AmBase is a holding company. At December 31, 2021, the Company’s assets consisted primarily of cash and cash equivalents. The Company is engaged in the management of its assets and liabilities. In June 2013, the Company purchased an equity interest in a real estate development property through a joint venture agreement to purchase and develop real property located at 105 through 111 West 57^th Street in New York, New York (the “111 West 57^th Property”). The Company is engaged in material disputes and litigation with regard to the 111 West 57^th Property. Despite ongoing litigation challenging the legitimacy of the actions taken in connection with the “Strict Foreclosure”, (as defined and as further discussed herein), the Company recorded an impairment for the full amount of its equity investment in the 111 West 57th Property in 2017. Prior to the Strict Foreclosure, the carrying value of the Company’s equity investment in the 111 West 57^th Property represented a substantial portion of the Company’s assets and net equity value. For additional information regarding the Company’s recording of an impairment of its equity investment in the 111 West 57^th Property in 2017 and the Company’s legal proceedings relating to the 111 West 57^th Property, including the Company’s challenge to the Strict Foreclosure, see Note 3 and Note 8. While the Company’s management is evaluating future courses of action to protect and/or recover the value of the Company’s equity investment in the 111 West 57^th Property, the adverse developments make it uncertain as to whether any such courses of action will be successful. Any such efforts are likely to require sustained effort over a period of time and substantial additional financial resources. Inability to recover all or most of such value would, in all likelihood, have a material adverse effect on the Company’s financial condition and future prospects. The Company can give no assurances with regard if it will prevail with respect to any of its claims. A fundamental principle of the preparation of financial statements in accordance with GAAP is the assumption that an entity will continue in existence as a going concern, which contemplates continuity of operations and the realization of assets and settlement of liabilities occurring in the ordinary course of business. In accordance with this requirement, the Company has prepared its accompanying consolidated financial statements assuming the Company will continue as a going concern. The Company has incurred operating losses for the past several years. The Company has continued to keep operating expenses at a reduced level; however, there can be no assurance that the Company’s current level of operating expenses will not increase or that other uses of cash will not be necessary. The Company believes that based on its current level of operating expenses its existing cash and cash equivalents may not be sufficient to cover operating cash needs through the twelve month period from the financial statement reporting date. Based on the above factors, management determined there is substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. The financial statements do not include adjustments to the carrying value of assets and liabilities which might be necessary should the Company not continue in operation. In order to continue as a going concern, the Company must take steps to manage its current level of cash and cash equivalents, through various ways, including but not limited to, raising additional capital through the sale of assets or long term borrowings, which may include additional borrowings from affiliates of the Company, reducing operating expenses, and seeking recoveries from various sources. There can be no assurance that the Company will be able to adequately implement these cash management measures, in whole or in part or sell any of its assets or raise capital on terms acceptable to the Company, if at all.