This bill requires the United States to use its voting power at major international financial institutions, such as the World Bank and regional development banks, to oppose new fossil fuel projects and investments while promoting clean energy instead. It specifically directs U.S. representatives to vote against any loans, investments, or financial assistance that would create or expand fossil fuel capacity, including efforts to extend the life of existing coal, oil, and gas infrastructure. The legislation also establishes a financial enforcement mechanism by requiring the Treasury Department to withhold U.S. contributions to any international financial institution that continues funding fossil fuel projects and hold those funds in escrow until the institution stops such financing. Additionally, the bill prohibits the U.S. government from providing any loans, insurance, guarantees, or technical assistance for fossil fuel activities through any of its own development finance agencies, including the Export-Import Bank and the U.S. International Development Finance Corporation. The Treasury Secretary must submit annual reports to Congress documenting fossil fuel funding by these institutions, though the bill does not specify an implementation deadline.