The Estate Tax rules are a complex set of rules in the tax code, which taxes the “taxable estate” of a decedent. The “taxable estate” is defined throughout the US Tax Code. An individual may pass a certain amount of money free from tax ($5.34 million in 2014). Due to portability rules, a married couple may transfer $10.68 million free from tax. If your estate is in excess of these amounts, you should consult with your lawyer as to a comprehensive estate plan, which may involve trusts, gifts, and other transfers to minimize your tax liability (40% for estates in excess of the exemption).