Sorry, I should have clarified... This is for a dual USA/Canadian citizen who resides in USA, who is filing USA taxes with IRS. Trying to put in the foreign (Canadian) investment income.
Understand that the U.S. return will NOT ask you for specific boxes or lines on the T3.
You'll enter your foreign earned income under the Personal Income section in Less Common Income >>Foreign Earned Income & Exclusion.
For any and all taxes of any kind withheld from that income and indicated on the T-3, you'll report that under the Deductions & Credits tab in Estimates & Other Taxes Paid >> Foreign Taxes.