In the Synodical letter from the Council of Constantinople, the bishops give a short summary of the catholic faith:
This is the faith which ought to be sufficient for you, for us, for all who wrest not the word of the true faith; for it is the ancient faith; it is the faith of our baptism; it is the faith that teaches us to believe in the name of the Father, of the Son, and of the Holy Ghost. According to this faith there is one Godhead, Power and Substance of the Father and of the Son and of the Holy Ghost; the dignity being equal, and the majesty being equal in three perfect hypostases, i.e. three perfect persons.
Godhead, Power, and Substance are all “of the Father and of the Son and of the Holy Ghost.” This is as conservative as it gets.
Important for us moderns, however, is to note that the power is one. Often we think of the Father’s power or the Son’s power or the Holy Ghost’s power as if they were individual powers, but the pro-Nicene’s used power as a means of unity, and thus it is really but another name for the divine essence.
We confess the one Power of the Father and of the Son and of the Holy Ghost.