Severance and unemployment, do they overlap? (Detroit)

My employer is paying severance in instalments and I am not sure whether to file now. I have a mortgage and need to plan. Who should I ask before signing?

Rules differ by state. I called the claims line and asked directly, then wrote down the answer and the date.

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.