Aon, based in Chicago, finished its acquisition of London's Benfield Group Ltd. Friday for $1.43 billion and said it was starting a "global restructuring plan" expected to eliminate between 500 and 700 jobs worldwide, the Chicago Tribune reported Saturday.

Company officials revealed the restructuring is expected to result in cumulative charges of $185 million spread out over three years but will also generate annual savings projected to reach $122 million per year by 2011, the Tribune said.

An Aon spokesman said the layoffs will happen both in Europe and the United States, primarily affecting back office functions rather than brokers. The spokesman couldn't say how many jobs would be eliminated in the Chicago area.