Either the amount paid into the plan or the cash value of the plan, whichever is the greater amount. Take note that the amount that will be received by the beneficiaries can be in lump sums or they can also send the amount through streams of payments. It will depend on the insurance company.
There are also different annuity plans available. There are some who feel that a big amount of cash that will be given in one payment will be better for the beneficiary. At times, the stream of payments is better as it can help the beneficiaries manage their finances better.