FDIC

aka Federal Deposit Insurance Corporation

It provides deposit insurance, which guarantees the safety of deposits in member banks, currently up to $250,000 per depositor per bank. Funds in non-interest bearing transaction accounts are fully insured, with no limit, under the temporary Transaction Account Guarantee Program. However, not all banks are participating in the TLGP/TAGP... Insured deposits are backed by the full faith and credit of the United States.

http://en.wikipedia.org/wiki/Federal_Deposit_Insurance_Corporation