The taxes imposed by foreign countries or possessions of the United States shall be allowed as a credit against the tax of a domestic insurance company subject to the tax imposed by section 801 or 831, to the extent provided in the case of a domestic corporation in section 901 (relating to foreign tax credit). For purposes of the preceding sentence (and for purposes of applying section 906 with respect to a foreign corporation subject to tax under this subchapter), the term “taxable income” as used in section 904 means—