The GDP (Gross Domestic Product) is the final total of goods and services created within a country (in this case, the USA) in a given time period (usually one year). The GNP (Gross National Product) is a little different, in that it includes the value of products and services created under the ownership of persons or companies within the USA, but can include production under their auspices in other countries as well. For purpose of answering your question I am using the GDP.
Interestingly, despite the technical difference between the two terms, the US GDP and GNP in 2010 were about equal at 14.6 Trillion dollars.
It is very difficult to find data on the contribution to the GDP by the entertainment industry alone. Usually the categories include entertainment and accommodation and food services.
The best estimate of the contribution to GDP of arts, entertainment and recreation is found for the year 2005 (reference 2). Here there is a category listed as “arts, entertainment, recreation, accommodation and food services” that accounted for 3.6% of the GDP.
Thus, in today’s economy, we can assume a GDP of around 15 Trillion, of which ¼ to ½ Trillion is produced by arts, entertainment and recreation.