What is the input impedance of an ideal voltage op-amp?

To get all the voltage from a source to a target without loss you need voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is more than ten times higher then the output impedance.
An input impedance is called also a load impedance or an external impedance.
An output impedance is called also a source impedance or an internal impedance.