The feds take 25% up front before you ever get any money from a jackpot. You might need to pay more when you file your taxes depending on what kind of measures you take to avoid paying taxes ( avoiding taxes is legal, evading taxes is illegal). Another good reason to have a good accountant working with you. Accountants and lawyers are licensed by the state and you can check them out with the state licensing board. They also are required to state their fees up front - and give you a written contract stating any and all fees if you choose to hire them- most of them charge by the hour though some will charge by the job. And for accountants or financial advisors you might be able to hire one on retainer (a yearly fee for them to do periodic work for you) If you win a big jackpot the state lottery office can provide you with a list of attorneys and accountants in your area. As for a family member or friend paying taxes on money you give them - it depends on how you set it up - the IRS limits gifts to individuals to $12,000 per year. Above that the recipient has to pay gift taxes. BUT if you engage and attorney and set up a family trust (or some other legal entity) so that the trust collects the jackpot then disperses the money as per your instructions - then the recipient(s) are responsible for taxes on what they receive - and you are responsible for taxes on the money you keep for your self. IF you collected the jackpot by yourself first then you would be responsible for taxes on the whole amount. So just for example say you won 20,000,000 in a lottery. And you set up a family trust and give 2,000,000 to a brother, 2,000,000 to a sister, and 2,000,000 to a son or daughter. And you keep 14,000,000 for your self. Each person receiving 2,000,000 would pay 25% to the IRS plus any state tax in the state where they live. And you would pay 25% on the 14,000,000.
However if you collected the 20,000,000 first and then give each person 2,000,000 - you'd pay 25% of the 20,000,000 to the IRS and then each person would have to pay gift tax on what they receive over $12,000 - and gift taxes can be really high - up to 35% or so. So yes the money would be taxed twice -
It really is in your best interests to hire compentent advisors BEFORE collecting a jackpot!