Do you know what information your wireless carrier hands over to the Fed?

We all have assumed that the government has the ability to spy on us, but are you aware of what specific information your wireless carrier keeps and legally has to hand over to them when requested?  Check out this article from Device Magazine that details, by carrier, what information they keep and how long they keep it for every customer.  The only truly surprising aspect of the information kept is how long they have to keep it.  For a lot, it's YEARS, not months.