It does not necessarily mean that you made a call. Com.android.phone is a package that includes many applications that control many different things, from system time to system settings to the Bluetooth adapter. It also includes the software that controls the actual phone functions, but, as I said, it does not necessarily mean there was a call made.
Unfortunately, all I can tell you it means is that your phone was doing something at that point. It may have been updating...although I'm not sure if that would show up. It's nothing to worry about, though.