You may check CBP web site for detail.
6q>iPK Jt jmq^98jB http://www.cbp.gov [&&#~gz }\8-&VoY#X The following is mentioned in U.S. Customs and Border Protection Declaration Form
iC iKr aW !L9|iC:8 Money And Other Monetary
fI0"#iv} Instruments
iY@}Q " You may bring into or take out of the country, including
m)<+?Bv y by mail, as much money as you wish. However, if
;7qzQ{Km it is more than $10,000, you will need to report it to
_7:Bxx4B CBP. Ask the CBP officer for the Currency Reporting
aDX&j2/ Form (FinCen 105). The penalties for non-compliance
%4x0^<k~ can be severe.
LNk :PD0m “Money” means monetary instruments and includes U.S.
~x'8T!M{ or foreign coins currently in circulation, currency, travelers’
!F}GSDDV* checks in any form, money orders, and negotiable
Z*q&^/N instruments or investment securities in bearer form.