You may check CBP web site for detail.
(m04Z2# mZ/B:)_ http://www.cbp.gov Bf'jXM{- ;xB"D0~,1 The following is mentioned in U.S. Customs and Border Protection Declaration Form
c_ygwO3.Q <u2*(BM4 Money And Other Monetary
6-KC[J^Xo Instruments
[p o+a@ % You may bring into or take out of the country, including
#Z$
6>
Xt by mail, as much money as you wish. However, if
0^E!P> it is more than $10,000, you will need to report it to
@z/]!n\~ CBP. Ask the CBP officer for the Currency Reporting
p6Z]oL q Form (FinCen 105). The penalties for non-compliance
qZ\zsOnp can be severe.
\|62E):i1 “Money” means monetary instruments and includes U.S.
/=e[(5X|O or foreign coins currently in circulation, currency, travelers’
_\]D<\St checks in any form, money orders, and negotiable
mnmwO(. instruments or investment securities in bearer form.