The move "reflects Moody's assessment that the federal government debt trajectory is on track to meet the criteria laid out in August 2011 for a return to a stable outlook," the rating service said.
The U.S. budget deficit was expected to decline over the next few years, Moody's said.
"Furthermore, the growth of the U.S. economy, which, while moderate, is currently progressing at a faster rate compared with several Aaa peers and has demonstrated a degree of resilience to major reductions in the growth of government spending," Moody's said in a statement released Thursday.
Moody's warned "without further fiscal consolidation efforts, government deficits are anticipated to increase once again over the long term."
"If left unaddressed, over time this situation could put the rating again under pressure," Moody's said.