Prometheus - Convert cpu_user_seconds to CPU Usage %?

I also found this way to get CPU Usage to be accurate:

100 - (avg by (instance) (irate(node_cpu_seconds_total{job="node",mode="idle"}[5m])) * 100)

From: http://www.robustperception.io/understanding-machine-cpu-usage/

Rate returns a per second value, so multiplying by 100 will give a percentage:

rate(container_cpu_user_seconds_total[30s]) * 100