The former president, 94, was hospitalised for a lung infection on 8 December (12) and underwent surgery to remove gallstones a week later.
He is expected to continue his recovery at home.
Meanwhile, former U.S. leader George H.W. Bush also spent Christmas in hospital after developing a fever.
The 88 year old was visited by his wife Barbara and his son Neil's family on Christmas Day (25Dec12), while sons George W. Bush and Jeb visited him before Christmas.