If a normal person has earned a huge amount of money as a gift from another, lets say a billion...

Just taxes need be paid. There are gift taxes and inherited taxes and earned income taxes off the interests earned off the money. . Other than that not much negative financial outcomes. As long as you pay the government there taxes you should be good. You might want to make sure that one billion dollars is insured. Some banks insure only like 100,000 to 250,000. . So you need to make sure it's covered with some kind of insurance. Some could say just leaving that much money in just regular saving account is dumb that you should invest it . But nothing negative should happen. Make sure the bank you using don't got hidden fees or something like that to take your money. I know I had 2000 in bank left it there and years later I came bank and they said they close my account as an inactive account. So if you are not going be adding to the account or using the account make sure they can't just close your accounts out. I wouldn't think one billion dollars would be closed out as easily as a 2000 dollar account. .