What is the voltage at the inverting input terminal of an op-amp, with respect to ground?
If you read the datasheet, Vp-Vn = Vio (input offset voltage), which should be close to ~3mV as the spec says. Ideally, you may think it should be zero.

Ip and In is the input bias current, Iib, which should be ~30pA. Your measurement seems to high, but your equipment may not go that sensitive.