Supplemental answer necessitated by the question of exactly how far Rosetta might have used its ion engines from the Sun found in comments below both of the other answers.
edit: I just found that these distances can also be confirmed in this answer.
I downloaded positions for Rosetta, the Sun, Earth, and comet 67P from JPL's Horizons at 1 day intervals and plotted them below.
Using the dates found in this answer for the beginning and end of hibernation 2011-06-08
and 2014-01-20
corresponding to distances from the Sun of 4.46 and 4.49 AU, there's no question that Juno at Jupiter with it's aphelion of 5.46 AU is unquestionably the winner.
Python plotting script: https://pastebin.com/wqrL3aQr
