Musannaf Ibn Abi Shayba 18:723

Abu Bakr narrated to us, he said: Isma'il bin Ibrahim narrated to us, from Ibn Abi Najih, from Mujahid and 'Ata', they both said: The blood money (diyah) of the Mu'ahid (a non-Muslim under a covenant of protection) is like the blood money of the Muslim.