CHICAGO – Power wholesaler Edison Mission Energy and its Chicago-based subsidiary Midwest Generation filed for Chapter 11 bankruptcy protection Monday to try to restructure about $5 billion in debt.

It wasn’t immediately clear what impact the move would have on Midwest Generation’s almost 1,000 Illinois employees.

In bankruptcy petitions filed in U.S. Bankruptcy Court Chicago, Edison Mission Energy listed $5.13 billion in assets and $5.1 billion in debt. Santa Ana, Calif.-based Edison Mission Energy is owned by the California utility Edison International.