Appearing as part of a series of ten sales in New York and Europe, the collection comes from Williams' two houses in California and Missouri, as well as his own Moon River Theate.
The sales will start at Christie's New York with Impressionist and Modern art works from the collection in their May 8-9 auction followed by post-War and Contemporary art in their day and evening sales on May 15-16.
Other works will be included in sales of American art, Latin American art, prints and multiples, African and Oceanic art and 20th Century decorative art and design, split between New York, London and Paris.
Christie's expect to raise more than $30m from the first post-War and Contemporary art offering alone.
Williams - who said that his alternative career would have been as an art dealer - was noted as a collector for his breadth of knowledge, enthusiasm and discernment.
Most prominently, the sales will include works by Willem de Kooning, Hans Hofmann, Richard Diebenkorn, Franz Kline, Jean-Michel Basquiat and Pablo Picasso.
Indeed, Williams was a particularly admirer of Willem de Kooning's art, amassing numerous paintings and bronze sculptures by the artist.
One of the highlights of the collection is Untitled XVII, produced during the artist's final years of painting. Executed in 1984, the auctioneers said it "possesses the dynamism and immediacy of the artist's best works".