That is a somewhat sensitive question to answer in absolute terms. From a historical perspective, during the 1990s, debt service costs were eating up roughly a third of federal revenues, if not more. That was an alarming situation. It's much less so now, given that it represents a much smaller proportion of federal revenues. However, we can still consider the other ways we could use that $46 billion if we didn't have to bear the costs of a debt of that size.
So two things can be said: From a global perspective, and from a historical one, that number isn't huge, but, $46.5 billion spent on debt servicing is still more than we allocate to national defence. It's also more than half of what we pay out in benefits to seniors, and it's about the same amount the federal government transfers to provinces for health care, or a little less. These are still significant amounts.