NEW YORK (MainStreet) – If you come under investigation by a law enforcement agency, you might have your cell phone record subpoenaed. How much they’ll actually be able to dig up depends a lot on which carrier you use.

The American Civil Liberties Union managed to get its hands on a Department of Justice document that advised law enforcement agencies on the data retention policies of the major cell phone carriers. The information the ACLU found gives customers a snapshot of how their carrier handles their data.

Here’s how long the three biggest carriers – Verizon, AT&T and Sprint – hold onto your data.

Subscriber information: 3-5 years
Call details (who you call or receive calls from): 1 year (rolling)
Cell towers used (which approximates your location): 1 year (rolling)
Text message detail: 1 year (rolling)
Text message content: Three to five days

TheStreet Recommends

Subscriber information: Depends on length of service
Call details: 5-7 years (varies for prepaid customers)
Cell towers: All towers used since July 2008
Text message detail: 5-7 years
Text message content: Not retained

Subscriber information: Unlimited
Call detail: 18-24 months
Cell towers: 18-24 months
Text message detail: 18 months, depending on device
Text message content: Not retained

For information on T-Mobile, Nextel and Virgin Mobile, as well as Internet browsing data policies, see the full document on the ACLU’s website.

The question this raises, then, is how often law enforcement agencies are actually taking advantage of this stored data -- something the ACLU is trying to answer. The civil liberties organization is in the process of filing more than 381 requests in 32 states to find out when police are obtaining cell phone records, how they’re doing it and what they’re using the information for.

—For the best rates on loans, bank accounts and credit cards, enter your ZIP code at