The below is taken from Hadith literature Its Origin, Development  and Special Features by M. Zubayr Siddiqi:

According to al-Daarimi, whenever any legal case came before Abu Bakr, he looked into the Quran, and decided the case on its basis. If he found no applicable judegement in the Quran he reffered to the usage of the Prophet. If he failed to find it there, he asked the other Companions, and if they informed him of any decision of the Prophet in the matter, he thanked God and decided the case accordingly. But if the Companions were unable to cite any Prophetic precedent, he gathered the leaders of the people; and after they arrived at an agreed decision, he judged accordingly.”

Sunan, Daarimi