Canadian pensions?
Where do I enter foreign pension income?
Where do I enter foreign pension income?
Line 16, just like other pensions.
Convert the Canadian amounts on the 1099R to US dollars; and don't forget to take the foreign tax credit on tax withheld (which also must be converted to US dollars).
You should submit an additional info statement explaining your calculations.

If this is from the Old Age Security or the Canada pension plan then it is treated for tax purposes by a U.S. resident as social security would under the totalization agreement between the U.S. and Canada (See publication 915, page 5). If this is the case I would enter it as if you were entering social security so the computer does the calculations for you.