Massive tax break package unveiled just before midnight

Congressional negotiators unveiled a massive legislative of tax breaks just before midnight Tuesday, part of talks over year-end spending legislation that could end a decades-long routine of extending temporary tax breaks and reshape the tax code

The proposed "extenders" legislation, hammered out between congressional negotiators in both parties, would make permanent many business tax breaks prized by Republicans that had previously been extended on a temporary basis. It would also make permanent low-income tax credits favored by the White House and Democrats.

The bill also includes a two-year delay of the medical device tax included in the Obamacare legislation, one of the sources of revenue used to pay for the expansion of health insurance coverage of the bill.

No estimate for the budgetary cost of the legislation was immediately available. Based on outside estimates of a similar package of tax breaks, however, the cost to the Treasury over 10 years could be around $800 billion on paper.