It was narrated from Makhramah bin Sulaiman that Kuraib - the freed slave of Ibn 'Abbas - told him:
"I asked Ibn 'Abbas: 'How did the Messenger of Allah (ﷺ) pray at night?' He said: 'He prayed eleven Rak'ahs including Witr, then he slept deeply until I could hear him snoring, then Bilal came to him and said: "The prayer, O Messenger of Allah!" Then he got up and prayed two brief Rak'ahs then led the people in prayer, and hedid not perform Wudu'.'" (FR)
English reference (FR): Vol. 1, Book 7, Hadith 687 (FR)
Arabic reference (FR): Book 7, Hadith 694 (FR)