"Estate" means a decedent's property, as that property:
(1) exists originally and as the property changes in form by sale, reinvestment, or otherwise;
(2) is augmented by any accretions and other additions to the property, including any property to be distributed to the decedent's representative by the trustee of a trust that terminates on the decedent's death, and substitutions for the property; and
(3) is diminished by any decreases in or distributions from the property.