Here are a few ways to rewrite the title in Swedish, depending on the tone you want:
Most natural news headline (using a colon):
Trump: Stort avtal med Ryssland kan vara på gång – involverar hela Europa
Slightly more formal:
Trump uppger att ett stort avtal med Ryssland kan vara under arbete, med hela Europa inblandat.
More concise/direct:
Trump: Stort Rysslandsavtal på gång – rör hela Europa
If you want to emphasize the ”major” aspect (more dramatic):
Trump: Jätteavtal med Ryssland kan bli verklighet – hela Europa inblandat
The first option is likely the best fit for a typical Swedish news headline, as it is direct and uses the dash to separate the two parts of the statement.