I was recently surprised to see I own 2 large control fields. Not sure where. Is there a way to use the Intel map to find control fields you own?
Nope. Sure, you can use the intel map. But there is no built-in way to automatically find those fields - or anything else, like portals you own.
Fields and links are not selectable items on the map, so can not be inspected and have no properties. So the only way how to identify your fields would be to search the "All" chat log, which is pretty futile.
But how do you actually know you own two large fields? Of course you can see you own two fields, but the "Mind Unit Control" in the "Now" tab might be misleading here. The units displayed there do not necessarily need to be based on fields you created. The value is based on the number of resonators you have deployed to field anchor portals. For better understanding: A field consists of 3 portals. One portal has 8 resonator slots. That makes 24 resonators for a field. If you own 1 resonator you get 1/24 of the MU for the created field. If you have 12 resonators you get 1/2 (12/24) of MU. Assume you own all 24 resonators and another player creates a field with those 3 portals, you get the full amount of MU - the player who creates the field gets none.
But don't get too excited now. This share does not count towards your all-time-stats or Illuminator badge - it is only added to the "Mind Unit Control" in the "Now" tab.