If you win a billion dollars it has to be safely kept somewhere. FDIC only guarantees up to $250,000. One reason why the wealthy have money in multiple banks.
besides, half of it would get invested in some long term, safe EFTs. Or maybe I just take it all out in cash, buy that entire mountain in Montana and build a fortress, or turn it into that place that norad has in Cheyenne Mountain hahahaah yes there is sarcasm here