The claim that the bill rescues over 2 billion family farms from the estate tax is false, as the number of family farms in the U.S. Is far less than 2 billion, with credible sources indicating the correct figure is around 2 million.
Trump: "Very importantly for Iowa, this bill rescues over 2 billion family farms from the so-called estate tax or the death tax."

FactVerify
Source: factverify.com
What the Evidence Shows
The claim made by Trump states that the bill rescues over 2 billion family farms from the so-called estate tax or death tax. This figure is factually incorrect because the total number of family farms in the United States is nowhere near 2 billion. According to multiple sources, including video and news reports from Trump's rally in Iowa, he misstated the number as 'over 2 billion' when the accurate estimate is closer to 'over 2 million' family farms.
The exaggeration by a factor of about 1,000 times makes the claim false. The estate tax provisions in recent legislation do provide relief to family farms, but not on a scale involving billions of farms, which is an impossible number given the U.S. Population and agricultural statistics.
Therefore, while there may be some truth that the bill helps family farms with estate tax issues, the specific claim about 'over 2 billion' farms rescued is demonstrably false and appears to be a verbal slip or exaggeration by Trump.