Sandy Ingram
You cannot exchange foreign currency without your passport [at an international airport]. The amount determines reporting requirements.
The limit is $10,000 per transaction per day. Therefore to exchange $100,000 you would need to exchange currency for approximately 10 days.
The same hold true when activating transaction over $10,000 at your local bank. Many time small foreign currency exchange services will report the transaction [to the IRS] even if it's under $10,000...