Employees have some new information on their W-2 forms for 2012 - the cost of their employer-provided health insurance.

This amount shows up in box 12 with the code DD. It includes what the employer and employee paid in premiums last year. To find out what your employer paid, subtract what you paid (look at your last pay stub for 2012) from the DD amount.

The amount in this box is not taxable, although many fear that could change as Congress looks for ways to raise revenues.

The cost of health coverage paid by your employer is not included in your income, but your employer can deduct it as a business expense. The share you pay is also excluded from your income; it's paid with pre-tax dollars.

The Affordable Care Act (Obamacare) required employers that provide group health coverage to report this cost to employees and the Internal Revenue Services on W-2s starting with 2012 forms. (The military and Indian tribal governments are exempt.)

The requirement is supposed to make employees more aware of health care costs. But it also "establishes the infrastructure for the tax treatment to change on employer-provided health care," says Christopher Renz, a partner with consulting firm Mercer.

The exclusion for group health care is the single biggest tax break. It will cost the government $164.2 billion in fiscal 2014, surpassing the exclusion on employer-provided pensions ($162.7 billion) and the mortgage-interest deduction ($99.8 billion), according to the Congressional Research Service.

Critics say this tax break encourages the over-consumption of health care. Various proposals have called for limiting it or phasing it out.

"I think it is a matter of time before it erodes in some fashion," Renz says. But he doubts that Congress will do away with it entirely. "Policymakers would have some concern that would cause more employers to stop providing health care and that's not what they want to do."

Employers had until Thursday to distribute 2012 W-2 forms.

Read the original:

W-2 forms now listing health care costs