The Milky Way halo is the brightest source of dark matter (DM) annihilation on the sky. Indeed, the strength of the Galactic dark matter signal can be greater than that expected from dwarf galaxies even in regions away from the Inner Galaxy. In this talk, I will demonstrate the promise of the Milky Way halo, until now less focused on in the literature, as a DM annihilation target. I will describe some of the intricacies associated with searching for an annihilation signal in a large-scale object such as the Milky Way halo. Finally, I will show the results of searching for this signal in Fermi gamma-ray data, producing some of the strongest bounds on DM annihilation to-date. I will conclude by describing the implications of these results for the DM interpretation of the Galactic Center excess.