FIG. 1 is a perspective view of a lid for a container embodying our new design; FIG. 2 is a front view of a lid for a container; FIG. 3 is a back view of a lid for a container; FIG. 4 is a left side view of a lid for a container; FIG. 5 is a right side view of a lid for a container; FIG. 6 is a top view of a lid for a container; and, FIG. 7 is a bottom view of a lid for a container;