Calulcate Total Time difference between two datetimes

Hi ,

I am working on a measure which calculates the total time difference between datetime columns in power bi.

I am using the below custom column to get this but my issue is that this creates a text type column which will not allow me to sum.

=Duration.ToText([AlarmClearedUTC]-[AlarmSentUTC])

Is there a way to get the time difference between datetimes which will then allow me to sum this up in a measure ?