The cost of providing health care for employees continues to increase, especially for large multinational firms. While the increases aren't as steep as they were a few years back, a study by Aon Hewitt shows that the increases still outstrip annual inflation and are costing big employers plenty.

Aon surveyed professionals, clients and carriers that participate in its portfolio of medical plans, and found that the expected 2015 increase, before plan design changes and vendor renegotiations, will be about 10.15 percent. In 2014, overall plan costs for this group rose 10.34 percent.

"Employer-sponsored medical plans globally will dip slightly in 2015, but continue to significantly exceed general inflation levels," the report stated, noting that the anticipated increase would be 6 percent higher than the inflation rate.