Confusion about storing and accessing variables

[Matt Hickok]

Hello, I'm trying to store a cisco device config in the fact cache, I'm doing it like this: 

    - name: "Get Config"

      register: config

      ios_command:

        commands: show running-config

    - name: "Store config as fact"

      set_fact:

        config: "{{ config.stdout }}"

        cacheable: true

While it's working, the resulting fact being created is the entire output from ios_command, meaning it includes changed, failed, stdout, and stdout_lines. 

I thought I was created a variable with "register: config" and then was storing just the stdout part of the variable by doing: config: "{{ config.stdout }}"

Is that not the proper way of accessing a variable?