Ayesha reported,
Her foster brother asked her about how the Prophet ﷺ used to perform the major ablution. She called for a vessel containing about a saa of water, set up a screen for privacy, and bathed. She poured water over her head three times.
Nasai 228
Hasanأخبرنا محمد بن عبد الأعلى قال حدثنا خالد قال حدثنا شعبة عن أبي بكر بن حفص سمعت أبا سلمة يقول دخلت على
عائشة رضي الله عنها
وأخوها من الرضاعة فسألها عن غسل النبي ﷺ فدعت بإناء فيه ماء قدر صاع فسترت سترا فاغتسلت فأفرغت على رأسها ثلاثا
Bukhari narrated it in the Book of Ghusl, chapter on ghusl with a saa or similar amount, no. 251, and Muslim, chapter... etc., no. 320, from the hadith of Shuba with the same wording, and it is in Kubra, in ghusl for janaba, water, and menstruation, the recommended amount, no. 232.Ayesha 
is the maternal aunt of Abu Salama through breastfeeding, her sister Umm Kulthum having nursed him, as Iyad said, (Fath al-Bari 1:365).