Idaho Statutes Title 15. Uniform Probate Code § 15-6-104. Right of survivorship

(a) Sums remaining on deposit at the death of a party to a joint account belong to the surviving party or parties as against the estate of the decedent if an intent to give the account can be shown by the surviving party or parties. If there are two (2) or more surviving parties, their respective ownerships during lifetime shall be in proportion to their previous ownership interests under section 15-6-103 of this Part augmented by an equal share for each survivor of any interest the decedent may have owned in the account immediately before his death; and the right of survivorship continues between the surviving parties.

(b) If the account is a P.O.D. account, on death of the original payee or of the survivor of two (2) or more original payees, any sums remaining on deposit belong to the P.O.D. payee or payees if surviving, or to the survivor of them if one (1) or more die before the original payee; if two (2) or more P.O.D. payees survive, there is no right of survivorship in event of death of a P.O.D. payee thereafter unless the terms of the account or deposit agreement expressly provide for survivorship between them.

(c) If the account is a trust account, on death of the trustee or the survivor of two (2) or more trustees, any sums remaining on deposit belong to the person or persons named as beneficiaries, if surviving, or to the survivor of them if one (1) or more die before the trustee, unless there is clear and convincing evidence of a contrary intent; if two (2) or more beneficiaries survive, there is no right of survivorship in event of death of any beneficiary thereafter unless the terms of the account or deposit agreement expressly provide for survivorship between them.

(d) In other cases, the death of any party to a multiple-party account has no effect on beneficial ownership of the account other than to transfer the rights of the decedent as part of his estate.

(e) A right of survivorship arising from the express terms of the account or under this section, if an intent to give can be shown, a beneficiary designation in a trust account, or a P.O.D. payee designation, cannot be changed by will.