Yes, there is some basic call reporting built into CUCM. You'll want to look for "CAR" - this can be found at:
Cisco Unified Serviceability -> Tools -> Cisco Unified CM CDR Analysis and Reporting
From there you'll want to Go to CDR -> Search.
Having said that, you may find that a third party call reporting tool is more user friendly. I recommend the free reporting tool VoIP Detective. You download the VM, deploy it on VMware or HyperV, and are able to pull a number of call reports. To your question specifically, you can create an outbound report that excludes any internal extensions.
