Can't Use Field (Float) in Visualization

[ntwrk80 (Ben Story)]

I've verified that my index is showing the right type for the field I want to make a line graph with, but it does not show up as an option for the Y-Axis if I choose an aggregation type. My data is a simple number groked from a syslog entry. I've tried mapping it both as an integer and a float. I've seen similar questions here and elsewhere, but they generally end up pointing to mapping which I think I'm doing. Pardon my newb ignorance please. authenticated_session_count is the field I'm working with.

{
  "mapping": {
    "_doc": {
      "_meta": {},
      "dynamic_templates": [
        {
          "message_field": {
            "path_match": "message",
            "match_mapping_type": "string",
            "mapping": {
              "norms": false,
              "type": "text"
            }
          }
        },
        {
          "string_fields": {
            "match": "*",
            "match_mapping_type": "string",
            "mapping": {
              "fields": {
                "keyword": {
                  "ignore_above": 256,
                  "type": "keyword"
                }
              },
              "norms": false,
              "type": "text"
            }
          }
        }
      ],
      "properties": {
        "@timestamp": {
          "type": "date"
        },
        "@version": {
          "type": "keyword"
        },
        "authenticated_session_count": {
          "type": "float",
          "ignore_malformed": false,
          "coerce": true
        },
...

[rudolf (Rudolf Meijering)]

Which version of the Elastic stack are you using? Can you share the output of GET <index>/_mapping?pretty=true (the JSON you shared doesn't exactly match the output format I expected)