In most of the lists that show instances or messages you can right-click the column headings and get a menu to select additional columns to display. Elapsed Time is available in the Job Monitor and History views and does what you want.
I have written this up for possible addition to the Job History report. We are also looking to add a new tool to make it easier to export data like that to a spreadsheet. In the meantime you might want to look at the report designer to add this: