While he didn't provide details, McConnell said on the Senate floor, "We've reached an agreement on all of the tax issues."

Multiple congressional sources tell CBS News that the two sides have agreed on a permanent income threshold for the expiration of the Bush-era tax cuts for the wealthiest Americans: $400,000 for individuals and $450,000 for families. For weeks, Democrats have pushed for letting the cuts expire for those making over $200,000 and families making over $250,000 while Republicans have wanted to renew the cuts for all Americans, including the wealthiest.

Additionally, agreement has been reached on the estate tax, which was set to increase from 35 percent to 55 percent in 2013. Instead, the compromise sets the new rate at 40 percent with the first $5 million exempt from being taxed.