Not quite — that’s for polarized light. For general light that may be unpolarized, you need four parameters. You can use the Stokes parameters, or, if you’re feeling very quantum, you can describe the full polarization state of a photon by a 2x2 density matrix. (I have never personally calculated this, but I’m pretty sure you can straightforwardly translate one formulation to the other — the density matrix captures the polarization distribution of a photon sampled, by whatever means, from any source of incoming light.)