Full Idea
Phenomenalism talks about actual and possible experiences, whereas idealism confines itself to the actual experiences.
Gist of Idea
Phenomenalism includes possible experiences, but idealism only refers to actual experiences
Source
Jonathan Dancy (Intro to Contemporary Epistemology [1985], 9.5)
Book Reference
Dancy,Jonathan: 'Introduction to Contemporary Epistemology' [Blackwell 1985], p.136