Why wait for 2014, when state health insurance exchanges for individuals go into effect, or 2017, when states can establish exchanges for large employers? At least that's what Aon Hewitt decided. The company will begin offering large companies—those with 1,000 or more workers—an exchange as early as next year.

Companies, including those that are self-insured, will select from a group of insurers providing plans that meet standards set by Aon and offer these to employees, with the company providing some portion of the premium.

Ken Sperling, global leader of Aon Hewitt's healthcare practice, says companies will offer sets of five plans, ranging from the most basic, dubbed bronze, to platinum. A company might provide employees with most or all of the cost of a bronze plan, with employees free to add their own funds to move up the ladder to plans that are more comprehensive or have lower deductibles.