The phone companies have saved this information for 3 years since the dawn of time. Records are kept of the numbers called, and text messages, and other account activity for 3 years.
Law enforcement has been able to obtain a warrant or go to the phone company and get this information at any time.
Here is an article from the ACLU.. AT&T even keeps recordings indefinitely. »
www.aclu.org/protecting- ··· -requestHere's one that includes info on land-lines.. »
www.privacyrights.org/pr ··· ing-trueI called the phone company about this in 2008; land-lines are fully logged and data is kept for at least 3 years through Qwest.
Articles on land-lines are more difficult to find if you search, just fyi...
This is why the NSAs PRISM program was never necessary, because the phone companies already retained the records. And you know how judge William Pauley whatever found it to be constitutional back in December? He did so saying that the reason it was necessary for meta-data collection was because some phone calls before 9/11 could not be traced, but all they had to do was get a warrant and go to the phone companies (meaning, the NSA had the ability to do look ups the whole time, an error in what the judge reported).