146c5814_What_is_an_Ideal_Op_Amp___Ideal_Op_Amp
[Characteristics] Zero Input Voltage Offset [Real Op Amp] A real op amp will have slight offset even if the voltage applied to the pins are the same. To correct this offset, voltage must be applied to the offset pin. [Ideal Op Amp] 
In an ideal op amp, if no voltage is applied to the inverting and noninverting input pins, the op amp will output a voltage of 0, since there is no difference at all of the voltage applied to the 2 input pins.
What is an Ideal Op Amp?
Ideal Op Amp