Officials noted the robust improvement in job growth, as well as consumer and business confidence. Several board members said the economy "may end up showing more momentum than anticipated," while others "thought that the boost to domestic spending from lower energy prices could turn out to be quite large," according to the minutes.

While they generally agreed on the direction of the U.S. economy, board members held a spirited debate over how best to word the Fed’s intentions. In the end, they decided to update its policy statement by saying it would be "patient" in moving toward a rate hike.

Officials also indicated that they might be willing to raise rates even if inflation hovers below the Fed’s 2-percent target, especially given that falling energy prices and a stronger dollar would keep prices muted for "some time."

The minutes stressed that the timing of the Fed’s rate hikes would be dependent on incoming economic data, although its choice of the word "patient" suggests that a rate hike is unlikely for at least the next two meetings, the minutes stated. That was a point also made by Fed Chair Janet Yellen at a news conference following the December meeting. The next gatherings are scheduled for later this month and in March.

The minutes were released with the customary three-week delay. At the meeting, the Fed added that its new language was consistent with its previous guidance that it would keep rates low for a "considerable time."

Many economists believe that the Fed will not start raising rates until June.

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