From the Document: "H.R. 3285 would update certain gender-related terms in the definition of the immediate family of a former President who are protected by law from threats. Specifically, the bill would replace the words wife and widow with spouse and surviving spouse in the law. The bill would not affect the total number of persons protected by such laws, so CBO [Congressional Budget Office] estimates that implementing H.R. 3285 would result in no cost to the federal government."
Congressional Budget Office: http://www.cbo.gov/