Low-profile High-value Bank Transfer?

Let me describe my question. Basically, there is one individual, with whom I share no blood or have had no previous contact, who needs to transfer a very large amount of money to my account. With "very large", I mean between 50 million and 1 billion USD. This money was acquired by him legally, from honorable origins.

Now here's the problem. Even IF the transfer was done legally, the authorities would no doubt be suspicious of such a large donation, with no goods being shipped in return. I would no doubt come under investigation, and my identity AND the nature of the "goods" must not be revealed. This is of the utmost importance to the continued existence of mankind. If its existence were to become public, I have no way of predicting what would happen next.

So that's the scenario. How would you make a transfer of such a large amount of money, without the authorities and other busybodies being all over you in no time?