You may check CBP web site for detail.
\=7=>x_ ku;nVV http://www.cbp.gov l,u{:JC @'*#]YU8 The following is mentioned in U.S. Customs and Border Protection Declaration Form
y.:- M@g
gLW Money And Other Monetary
JJ
?ri, Instruments
~It+|X=Kx You may bring into or take out of the country, including
M:M>@|) by mail, as much money as you wish. However, if
Z5Ihc%J^ it is more than $10,000, you will need to report it to
XyphQ}\u CBP. Ask the CBP officer for the Currency Reporting
E ZKz-} Form (FinCen 105). The penalties for non-compliance
~Ls I<z can be severe.
-^H5z+"^ “Money” means monetary instruments and includes U.S.
(u&yb!` or foreign coins currently in circulation, currency, travelers’
0NtsFPO checks in any form, money orders, and negotiable
_
-\s[p5 instruments or investment securities in bearer form.