Aon Corp. agreed to buy Hewitt Associates, Inc. for $4.9 billion in cash and stock, according to an announcement Monday. The merger will integrate Hewitt with Aon's existing consulting and outsourcing operations (Aon Consulting) and operate the segment globally under the newly created Aon Hewitt brand.

Hewitt helps more than 3,000 clients and their employees around the world anticipate and solve benefits, talent, and related financial challenges through three primary business lines: consulting, benefits outsourcing and HR business process outsourcing.

According to a news release, "Hewitt, combined with Aon Consulting, will build upon those strengths, creating a global leader in human capital solutions, with diverse product and service capabilities and world-class associates to effectively serve clients' evolving needs."