You may bring into or take out of the country, including by mail, as much money as you wish. However, if it is more than $10,000, you will need to report it to CBP. Ask the CBP officer for the Currency Reporting Form (FinCen 105). The penalties for non-compliance can be severe.
“Money” means monetary instruments and includes U.S. or foreign coins currently in circulation, currency, travelers’ checks in any form, money orders, and negotiable instruments or investment securities in bearer form.
“Money” means monetary instruments and includes U.S. or foreign coins currently in circulation, currency, travelers’ checks in any form, money orders, and negotiable instruments or investment securities in bearer form.
http://www.cbp.gov/xp/cgov/travel/vacation/kbyg/money.xml
拉卡,汇票或转账其实也是一样的,申报手续是由银行帮你代劳了。