His shock death comes after a 30-year-rule in an oil-rich nation long rocked by various insurgencies, which will now be ruled by Deby's son, the four-star general Mahamat Idriss Deby Itno.
Chad's army dissolved government and parliament after announcing the death of President Deby on Tuesday, but vowed "free and democratic" elections following an 18-month transition period.
The army had earlier announced that one of Deby's sons would replace him as the head of a military council following the death of the leader who had ruled the country with an iron fist for three decades.