Who decides the "reasonableness" of attorney fees — judge or jury?

The Tenth Circuit held that it depends.  If you ask for fees just because you won, the person in the black robe does the work.  But if you seek fees as "damages", the question must go to the jury.

The dispute pitted Chevron against J. R. Simplot.  Chevron owned a phosphate mine, a phosphate processing plant, and a 97-mile pipeline linking the two. 

Another phosphate miner, Ashley Creek, sued Chevron for denying it access to the pipeline.  It alleged antitrust violations. 

Later, Simplot offered to buy Chevron out of the operation but insisted that Chevron agree to defend Simplot if Ashley Creek brought it into the case.  Chevron said fine.  The deal closed. 

Sure enough, after Ashley Creek sued Simplot also, Chevron rejected Simplot's demands that Chevron cover Simplot's defense costs.  Ashley Creek lost the litigation but not until Simplot paid $5.1 million in fees and expenses.

Simplot sued Chevron to get its money back.  The district court granted summary judgment for Simplot and awarded it the $5.1 million it requested.  The Tenth Circuit upheld the summary judgment on liability but reversed the award of fees and costs.  Remanding, the court instructed that the seventh amendment required a jury to decide "any portion of Simplot's damages claim [for attorneys' fees] that cannot be resolved as a matter of law."  J. R. Simplot v. Chevron Pipeline Co., No 07-4074, slip op. at 35 (10th Cir. Apr. 23, 2009).