Almost every U.S. taxpayer faces a significant increase unless Congress and the White House agree on a plan to extend a huge collection of tax cuts expiring at the end of the year. There's disagreement over whether to extend them for all or to let taxes rise for some part of the wealthiest Americans, such as individuals making more than $200,000 per year.

There's also a big debate over how to overhaul the tax code to make it simpler, with lower rates balanced by fewer deductions. Millions of people count on the mortgage interest deduction, child tax credit and more. So finding agreement on reducing tax breaks is a titanic task, even though most lawmakers say they would like to simplify taxes.