If you are the account owner, log into your MyVerizon account. On the next screen choose VIEW BILL. Next screen use the drop down menu to choose the month in question. Then choose, 'View Printable Bill"
If you press the "Send" key it should bring up your call log; mine goes back quite a few months so you may be able to see it directly on the phone, unless you have deleted your call logs.
Otherwise, budone's suggestion to view the details online will work. Call information is available for the previous 12 months and even further back (for a fee) if needed.