The more money you have the more time it takes to manage it.
The GOVERNMENT insures people's deposits up to $100,000 to prevent your average person from losing everything if their bank goes under. This also creates CONFIDENCE in the banking system, so that people will not do a run on the banks of times are tough, making them worse, and crashing the financial system.
There is no reasonable reason for them to insure $100,000,000.
1. You would be perfectly fine even if you lost 90% of your money.
2. Wealthy people usually know to split their money up, so they will be protected by the fact that if one bank fails, they will only lose a small portion of their money.
3. Wealthy people usually have a better understanding of the economy and are less likely to see a story on the news about AIG or LEH and irrationally go down to the banks and start pulling all their money out.
4. Banks are a poor investment vehicle. Most people with money put some of it in the bank for the banks security (they rarely fail and are insured).
5. When banks fail they rarely went from having 100% of their deposits covered to having 0% covered in modern times with strict regulation. If you had $2,000,000 in a bank account and it got shut down, your bank would most probably be taken over by another bank, who would assume any uncovered bank accounts with the assistance of the FDIC if necessary, and you will probably automatically keep all your money. It would be very rare for you to lose much.
I do not know a single person who has more than $100,000 in assets outside of the value of their home, car, and business that does not invest.
My grandfather for example, who recently passed. He had lived through the great depression, and was very careful. He had it split into bank accounts of $75,000 each, but he also bought mutual funds, and left money in them for decades. It is pretty amazing seeing the starting and ending balances on investment vehicles that were purchased 20-30 years ago and just left to accrue value.
Investing is a very normal thing to do, and not a bad idea as long as risk is managed.
Every 10-20 years there will be a major financial crisis. Those who diversify their assets will only suffer a little bit. Those who put it all in one place may come through fine or may really take a hard hit.
If you want to invest and not worry about it, hire a financial consultant. Talk to him about your goals, and make sure he is someone who can get them done for you. If you talk to him and it sounds like he wants to be a lot more aggresive with your money then you want, find a different financial advisor. Once you find a consultant that matches your needs, make sure he understand that you want to be a good steward to the money, so that it will last for generations. You want to diversify your interests as much as possible, and invest in low risk reasonable yield investments for maximum safety. He should be able to help pick your investments for you, and give you a profile where the risk is distributed in such a way where you have a decent yield, but is very safe.
Also, remember that with that much money, you can always take $1,000,000 put it in Euros, fly to Switzerland, and put it in a safe deposit box deep in the Alps, incase your luck really goes south.