Cleaving damage is done by trying to sever and chop. Hew attacks is a fair name for it too.
Cleaving uses your Strength modifier.
For resistances and vulnerabilities Cleaving counts as 50% Slashing & 50% Bludgeoning
Modifier: Strength
Damage Type: 50% Slashing, 50% Bludgeoning
Penetration: 1
Damage die: High