46% of "households" don't pay according to the Tax Policy Center .
All Fed taxes != Fed income taxes.

http://lifeinc.today.msnbc.msn.com/...be-paying-federal-income-taxes-this-year?liteRoberton Williams, senior fellow with the Tax Policy Center, said more than half of those who pay no federal income tax are still on the hook for payroll taxes, which are used mainly to fund Social Security and Medicare.
In addition, most people end up paying sales taxes as well as federal excise taxes on gasoline, alcohol and other products.
"Almost everyone is going to pay a tax somewhere along the way," he said.
Williams said that the percentage of people who will pay no income taxes this year actually is expected to be slightly lower than in the past two years, when tax credits designed to stimulate the economy allowed even more people to zero out their federal income tax bill.