How long does a copyright last?

As the Copyright Website puts it:

Generally, when you think of copyright term, you think in terms of the author's lifespan, plus some bonus years. However, as Congress keeps extending the bonus years in an interminable game of hopscotch to keep Micky Mouse out of the public domain, the calculus for determining copyright term becomes a little more. In fact, as you can see in the flowchart below, the calculus really begins to look like calculus.

Lolly Gasaway of the University of North Carolina provides a useful chart that confirms the above characterization that calculating the duration of a copyright is, to put it mildly, difficult.

The original copyright registration to Que Sera, Sera from 1956 was renewed in 1984.

Ray Evans died in 2007.

Jay Livingston died in 2001.

After their deaths, the copyright to Que Sera, Sera was assigned to Jaylivingston Music and St. Angelo Music.