Enron Corp., which helped push California's controversial power-deregulation bill through the Legislature five years ago and now is one of the state's largest energy providers, filed for Chapter 11 on Sunday. The Houston-based firm listed $50 billion in assets and $31 billion in liabilities, making Enron's filing the largest in history.

Enron's bankruptcy filing did not include billions of dollars more in debts from several different partnerships, many of which have soured. Until now, the largest bankruptcy in history was Texaco Inc., which claimed $36 billion in assets when it filed in 1987.

In California, Enron provides enough energy to power as many as 1 million commercial and residential properties a day. It also works as a broker, or middleman, to secure additional power for some utilities in the state.