Without it, more than 2 million of the long-term unemployed would have run out of benefits at the end of this year, according to the National Employment Law Project, an advocacy group.

Continuing the benefit extension for one year will cost an estimated $30 billion.

Prevent a cut in Medicare doctors' pay: The Biden-McConnell compromise will prevent a scheduled 27% cut in reimbursement for Medicare services for one year. The so-called "doc fix" will boost the deficit by $31 billion.

Replace sequester for 2 months: The dreaded sequester -- the automatic and blunt spending cuts to defense and nondefense programs -- will be replaced for two months in 2013.

The two months of cuts will be replaced by $12 billion in new revenue and $12 billion in spending cuts.

It's not clear what Congress will decide to do about the sequester after the two months are up. If left in place for the whole year, the sequester would have reduced spending authority in 2013 by roughly $110 billion.