That is first and foremost the role of the Office of the Superintendent of Financial Institutions. Its mandate is to protect not just depositors and creditors but policyholders on the insurance side as well. One of the key ways in which it does that is by ensuring that federally regulated life and health insurers hold enough regulatory capital against the investments they make, and that the amount of capital held is commensurate with the risk profile of the given investment, the credit risk, the regulatory risk, the operational risk, such that there would be an adequate amount of capital available to that institution to weather an unexpected event.
That being said, I don't work for the superintendent's office. I'm sure it could give you a far more detailed account of how it goes about that, but that is first and foremost the safety net that exists to ensure policyholders can be confident that their life and health insurance companies are investing soundly.