I hope that I don't upset anybody, but that sort of information has been on file with major telephone companies for over a dozen years. Telephone switches are now computers. All of the call info such as start and end times and the header are logged. How else could you get billed for your long-distance calls etc... That info goes to tape and gets backed up regularly. From there, it is just a matter of how long the phone company wants to hold on to those tapes. They are NOT recording the content of your calls, just the start and stop times and phone numbers involved etc...
Those tapes DO get kept and used. A company that I used to work for used them to convict a guy of placing over 750 obscene phone calls. As cheap as memory has become don't count on ANYTHING being deleted anymore. Some day, forensic anthrologists might reconstruct today's society from our data tapes instead of our pot shards.